WorldWideScience

Sample records for strongly lensed lyman

  1. Weak lensing of the Lyman α forest

    Science.gov (United States)

    Croft, Rupert A. C.; Romeo, Alessandro; Metcalf, R. Benton

    2018-06-01

    The angular positions of quasars are deflected by the gravitational lensing effect of foreground matter. The Lyman α (Lyα) forest seen in the spectra of these quasars is therefore also lensed. We propose that the signature of weak gravitational lensing of the Lyα forest could be measured using similar techniques that have been applied to the lensed cosmic microwave background (CMB), and which have also been proposed for application to spectral data from 21-cm radio telescopes. As with 21-cm data, the forest has the advantage of spectral information, potentially yielding many lensed `slices' at different redshifts. We perform an illustrative idealized test, generating a high-resolution angular grid of quasars (of order arcminute separation), and lensing the Lyα forest spectra at redshifts z = 2-3 using a foreground density field. We find that standard quadratic estimators can be used to reconstruct images of the foreground mass distribution at z ˜ 1. There currently exists a wealth of Lyα forest data from quasar and galaxy spectral surveys, with smaller sightline separations expected in the future. Lyα forest lensing is sensitive to the foreground mass distribution at redshifts intermediate between CMB lensing and galaxy shear, and avoids the difficulties of shape measurement associated with the latter. With further refinement and application of mass reconstruction techniques, weak gravitational lensing of the high-redshift Lyα forest may become a useful new cosmological probe.

  2. SPITZER ULTRA FAINT SURVEY PROGRAM (SURFS UP). II. IRAC-DETECTED LYMAN-BREAK GALAXIES AT 6 ≲ z ≲ 10 BEHIND STRONG-LENSING CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Kuang-Han; Bradač, Maruša; Hoag, Austin; Cain, Benjamin; Lubin, L. M.; Knight, Robert I. [University of California Davis, 1 Shields Avenue, Davis, CA 95616 (United States); Lemaux, Brian C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Ryan, R. E. Jr.; Brammer, Gabriel B. [Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Castellano, Marco; Amorin, Ricardo; Fontana, Adriano; Merlin, Emiliano [INAF—Osservatorio Astronomico di Roma Via Frascati 33, I-00040 Monte Porzio Catone (Italy); Schmidt, Kasper B. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Schrabback, Tim [Argelander-Institut für Astronomie, Auf Dem Hügel 71, D-53121 Bonn (Germany); Treu, Tommaso [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095 (United States); Gonzalez, Anthony H. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Linden, Anja von der, E-mail: khhuang@ucdavis.edu, E-mail: astrokuang@gmail.com [Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305 (United States)

    2016-01-20

    We study the stellar population properties of the IRAC-detected 6 ≲ z ≲ 10 galaxy candidates from the Spitzer UltRa Faint SUrvey Program. Using the Lyman Break selection technique, we find a total of 17 galaxy candidates at 6 ≲ z ≲ 10 from Hubble Space Telescope images (including the full-depth images from the Hubble Frontier Fields program for MACS 1149 and MACS 0717) that have detections at signal-to-noise ratios  ≥ 3 in at least one of the IRAC 3.6 and 4.5 μm channels. According to the best mass models available for the surveyed galaxy clusters, these IRAC-detected galaxy candidates are magnified by factors of ∼1.2–5.5. Due to the magnification of the foreground galaxy clusters, the rest-frame UV absolute magnitudes M{sub 1600} are between −21.2 and −18.9 mag, while their intrinsic stellar masses are between 2 × 10{sup 8}M{sub ⊙} and 2.9 × 10{sup 9}M{sub ⊙}. We identify two Lyα emitters in our sample from the Keck DEIMOS spectra, one at z{sub Lyα} = 6.76 (in RXJ 1347) and one at z{sub Lyα} = 6.32 (in MACS 0454). We find that 4 out of 17 z ≳ 6 galaxy candidates are favored by z ≲ 1 solutions when IRAC fluxes are included in photometric redshift fitting. We also show that IRAC [3.6]–[4.5] color, when combined with photometric redshift, can be used to identify galaxies which likely have strong nebular emission lines or obscured active galactic nucleus contributions within certain redshift windows.

  3. The Sunburst Arc: Direct Lyman α escape observed in the brightest known lensed galaxy

    Science.gov (United States)

    Rivera-Thorsen, T. E.; Dahle, H.; Gronke, M.; Bayliss, M.; Rigby, J. R.; Simcoe, R.; Bordoloi, R.; Turner, M.; Furesz, G.

    2017-11-01

    We present rest-frame ultraviolet and optical spectroscopy of the brightest lensed galaxy yet discovered, at redshift z = 2.4. The source reveals a characteristic triple-peaked Lyman α profile that has been predicted in various theoretical works, but to our knowledge has not been unambiguously observed previously. The feature is well fit by a superposition of two components: a double-peak profile emerging from substantial radiative transfer, and a narrow, central component resulting from directly escaping Lyman α photons, but it is poorly fit by either component alone. We demonstrate that the feature is unlikely to contain contamination from nearby sources, and that the central peak is unaffected by radiative transfer effects except for very slight absorption. The feature is detected at signal-to-noise ratios exceeding 80 per pixel at line center, and bears strong resemblance to synthetic profiles predicted by numerical models. Based on observations obtained at the Magellan-I (Baade) Telescope at Las Campanas Observatory, Chile.

  4. TWO LENSED z ≅ 3 LYMAN BREAK GALAXIES DISCOVERED IN THE SDSS GIANT ARCS SURVEY

    International Nuclear Information System (INIS)

    Koester, Benjamin P.; Gladders, Michael D.; Sharon, Keren; Wuyts, Eva; Bayliss, Matthew B.; Hennawi, Joseph F.; Rigby, J. R.; Dahle, Hakon

    2010-01-01

    We report the discovery of two strongly lensed z ∼ 3 Lyman break galaxies (LBGs) discovered as u-band dropouts as part of the SDSS Giant Arcs Survey (SGAS). The first, SGAS J122651.3+215220 at z = 2.9233, is lensed by one of several sub-clusters, SDSS J1226+2152, in a complex massive cluster at z = 0.43. Its (g, r, i) magnitudes are (21.14, 20.60, 20.51) which translate to surface brightnesses, μ g,r,i , of (23.78, 23.11, 22.81). The second, SGAS J152745.1+065219, is an LBG at z = 2.7593 lensed by the foreground SDSS J1527+0652 at z = 0.39, with (g, r, z) = (20.90, 20.52, 20.58) and μ g,r,z = (25.15, 24.52, 24.12). Moderate resolution spectroscopy confirms the redshifts suggested by photometric breaks and shows both absorption and emission features typical of LBGs. Lens mass models derived from combined imaging and spectroscopy reveal that SGAS J122651.3+215220 is a highly magnified source (M ≅ 40), while SGAS J152745.1+065219 is magnified by no more than M ≅ 15. Compared with LBG survey results, the luminosities and lensing-corrected magnitudes suggest that SGAS J122651.3+215220 is among the faintest ≅20% of LBGs in that sample. SGAS J152745.1+065219, on the other hand, has an unlensed r-band apparent magnitude similar to that of the 'Cosmic Eye', which places it near the mean of LBG survey results over similar redshifts.

  5. Subaru Weak Lensing Measurements of Four Strong Lensing Clusters: Are Lensing Clusters Over-Concentrated?

    Energy Technology Data Exchange (ETDEWEB)

    Oguri, Masamune; Hennawi, Joseph F.; Gladders, Michael D.; Dahle, Haakon; Natarajan, Priyamvada; Dalal, Neal; Koester, Benjamin P.; Sharon, Keren; Bayliss, Matthew

    2009-01-29

    We derive radial mass profiles of four strong lensing selected clusters which show prominent giant arcs (Abell 1703, SDSS J1446+3032, SDSS J1531+3414, and SDSS J2111-0115), by combining detailed strong lens modeling with weak lensing shear measured from deep Subaru Suprime-cam images. Weak lensing signals are detected at high significance for all four clusters, whose redshifts range from z = 0.28 to 0.64. We demonstrate that adding strong lensing information with known arc redshifts significantly improves constraints on the mass density profile, compared to those obtained from weak lensing alone. While the mass profiles are well fitted by the universal form predicted in N-body simulations of the {Lambda}-dominated cold dark matter model, all four clusters appear to be slightly more centrally concentrated (the concentration parameters c{sub vir} {approx} 8) than theoretical predictions, even after accounting for the bias toward higher concentrations inherent in lensing selected samples. Our results are consistent with previous studies which similarly detected a concentration excess, and increases the total number of clusters studied with the combined strong and weak lensing technique to ten. Combining our sample with previous work, we find that clusters with larger Einstein radii are more anomalously concentrated. We also present a detailed model of the lensing cluster Abell 1703 with constraints from multiple image families, and find the dark matter inner density profile to be cuspy with the slope consistent with -1, in agreement with expectations.

  6. Cosmological applications of strong gravitational lensing

    DEFF Research Database (Denmark)

    Paraficz, Danuta

    value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown...

  7. Bias of damped Lyman-α systems from their cross-correlation with CMB lensing

    Science.gov (United States)

    Alonso, D.; Colosimo, J.; Font-Ribera, A.; Slosar, A.

    2018-04-01

    We cross-correlate the positions of damped Lyman-α systems (DLAs) and their parent quasar catalog with a convergence map derived from the Planck cosmic microwave background (CMB) temperature data. We make consistent measurements of the lensing signal of both samples in both Fourier and configuration space. By interpreting the excess signal present in the DLA catalog with respect to the parent quasar catalog as caused by the large scale structure traced by DLAs, we are able to infer the bias of these objects: bDLA=2.6±0.9. These results are consistent with previous measurements made in cross-correlation with the Lyman-α forest, although the current noise in the lensing data and the low number density of DLAs limits the constraining power of this measurement. We discuss the robustness of the analysis with respect to a number different systematic effects and forecast prospects of carrying out this measurement with data from future experiments.

  8. Strong gravitational lensing by Sgr A*

    International Nuclear Information System (INIS)

    Bin-Nun, Amitai Y

    2011-01-01

    In recent years, there has been increasing recognition of the potential to use the galactic center as a probe of general relativity in the strong field. There is almost certainly a black hole at Sgr A* in the galactic center, and this would allow us to have the opportunity to probe dynamics near the exterior of the black hole. In the last decade, there has been theoretical research into extreme gravitational lensing in the galactic center. Unlike in most applications of gravitational lensing, where the bending angle is of the order of, at most, an arc minute, very large bending angles are possible for light that closely approaches a black hole. Photons may even loop multiple times around a black hole before reaching the observer. There have been many proposals to use light's close approach to the black hole as a probe of the black hole metric. Of particular interest are the properties of images formed from the light of S stars orbiting in the galactic center. This paper will review some of the attempts made to study extreme lensing as well as extend the analysis of S star lensing. In particular, we are interested in the effect of a Reissner-Nordstrom like 1/r 2 term in the metric and how this would affect the properties of relativistic images.

  9. Can strong gravitational lensing constrain dark energy?

    International Nuclear Information System (INIS)

    Lee, Seokcheon; Ng, K.-W.

    2007-01-01

    We discuss the ratio of the angular diameter distances from the source to the lens, D ds , and to the observer at present, D s , for various dark energy models. It is well known that the difference of D s s between the models is apparent and this quantity is used for the analysis of Type Ia supernovae. However we investigate the difference between the ratio of the angular diameter distances for a cosmological constant, (D ds /D s ) Λ , and that for other dark energy models, (D ds /D s ) other , in this paper. It has been known that there is lens model degeneracy in using strong gravitational lensing. Thus, we investigate the model independent observable quantity, Einstein radius (θ E ), which is proportional to both D ds /D s and velocity dispersion squared, σ v 2 . D ds /D s values depend on the parameters of each dark energy model individually. However, (D ds /D s ) Λ -(D ds /D s ) other for the various dark energy models, is well within the error of σ v for most of the parameter spaces of the dark energy models. Thus, a single strong gravitational lensing by use of the Einstein radius may not be a proper method to investigate the property of dark energy. However, better understanding to the mass profile of clusters in the future or other methods related to arc statistics rather than the distances may be used for constraints on dark energy

  10. The Strong Lensing Time Delay Challenge (2014)

    Science.gov (United States)

    Liao, Kai; Dobler, G.; Fassnacht, C. D.; Treu, T.; Marshall, P. J.; Rumbaugh, N.; Linder, E.; Hojjati, A.

    2014-01-01

    Time delays between multiple images in strong lensing systems are a powerful probe of cosmology. At the moment the application of this technique is limited by the number of lensed quasars with measured time delays. However, the number of such systems is expected to increase dramatically in the next few years. Hundred such systems are expected within this decade, while the Large Synoptic Survey Telescope (LSST) is expected to deliver of order 1000 time delays in the 2020 decade. In order to exploit this bounty of lenses we needed to make sure the time delay determination algorithms have sufficiently high precision and accuracy. As a first step to test current algorithms and identify potential areas for improvement we have started a "Time Delay Challenge" (TDC). An "evil" team has created realistic simulated light curves, to be analyzed blindly by "good" teams. The challenge is open to all interested parties. The initial challenge consists of two steps (TDC0 and TDC1). TDC0 consists of a small number of datasets to be used as a training template. The non-mandatory deadline is December 1 2013. The "good" teams that complete TDC0 will be given access to TDC1. TDC1 consists of thousands of lightcurves, a number sufficient to test precision and accuracy at the subpercent level, necessary for time-delay cosmography. The deadline for responding to TDC1 is July 1 2014. Submissions will be analyzed and compared in terms of predefined metrics to establish the goodness-of-fit, efficiency, precision and accuracy of current algorithms. This poster describes the challenge in detail and gives instructions for participation.

  11. Using Strong Gravitational Lensing to Identify Fossil Group Progenitors

    Science.gov (United States)

    Johnson, Lucas E.; Irwin, Jimmy A.; White, Raymond E., III; Wong, Ka-Wah; Maksym, W. Peter; Dupke, Renato A.; Miller, Eric D.; Carrasco, Eleazar R.

    2018-04-01

    Fossil galaxy systems are classically thought to be the end result of galaxy group/cluster evolution, as galaxies experiencing dynamical friction sink to the center of the group potential and merge into a single, giant elliptical that dominates the rest of the members in both mass and luminosity. Most fossil systems discovered lie within z fossil criteria within the look forward time. Since strong gravitational lensing preferentially selects groups merging along the line of sight, or systems with a high mass concentration like fossil systems, we searched the CASSOWARY survey of strong-lensing events with the goal of determining whether lensing systems have any predisposition to being fossil systems or progenitors. We find that ∼13% of lensing groups are identified as traditional fossils while only ∼3% of nonlensing control groups are. We also find that ∼23% of lensing systems are traditional fossil progenitors compared to ∼17% for the control sample. Our findings show that strong-lensing systems are more likely to be fossil/pre-fossil systems than comparable nonlensing systems. Cumulative galaxy luminosity functions of the lensing and nonlensing groups also indicate a possible, fundamental difference between strong-lensing and nonlensing systems’ galaxy populations, with lensing systems housing a greater number of bright galaxies even in the outskirts of groups.

  12. Strong deflection lensing by a Lee–Wick black hole

    Directory of Open Access Journals (Sweden)

    Shan-Shan Zhao

    2017-11-01

    Full Text Available We study strong deflection gravitational lensing by a Lee–Wick black hole, which is a non-singular black hole generated by a high derivative modification of Einstein–Hilbert action. The strong deflection lensing is expected to produce a set of relativistic images very closed to the event horizon of the black hole. We estimate its observables for the supermassive black hole in our Galactic center. It is found that the Lee–Wick black hole can be distinguished from the Schwarzschild black hole via such lensing effects when the UV scale is not very large, but the requiring resolution is much higher than current capability.

  13. Constraints on cosmological models from strong gravitational lensing systems

    International Nuclear Information System (INIS)

    Cao, Shuo; Pan, Yu; Zhu, Zong-Hong; Biesiada, Marek; Godlowski, Wlodzimierz

    2012-01-01

    Strong lensing has developed into an important astrophysical tool for probing both cosmology and galaxies (their structure, formation, and evolution). Using the gravitational lensing theory and cluster mass distribution model, we try to collect a relatively complete observational data concerning the Hubble constant independent ratio between two angular diameter distances D ds /D s from various large systematic gravitational lens surveys and lensing by galaxy clusters combined with X-ray observations, and check the possibility to use it in the future as complementary to other cosmological probes. On one hand, strongly gravitationally lensed quasar-galaxy systems create such a new opportunity by combining stellar kinematics (central velocity dispersion measurements) with lensing geometry (Einstein radius determination from position of images). We apply such a method to a combined gravitational lens data set including 70 data points from Sloan Lens ACS (SLACS) and Lens Structure and Dynamics survey (LSD). On the other hand, a new sample of 10 lensing galaxy clusters with redshifts ranging from 0.1 to 0.6 carefully selected from strong gravitational lensing systems with both X-ray satellite observations and optical giant luminous arcs, is also used to constrain three dark energy models (ΛCDM, constant w and CPL) under a flat universe assumption. For the full sample (n = 80) and the restricted sample (n = 46) including 36 two-image lenses and 10 strong lensing arcs, we obtain relatively good fitting values of basic cosmological parameters, which generally agree with the results already known in the literature. This results encourages further development of this method and its use on larger samples obtained in the future

  14. Constraints on cosmological models from strong gravitational lensing systems

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Shuo; Pan, Yu; Zhu, Zong-Hong [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Biesiada, Marek [Department of Astrophysics and Cosmology, Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Godlowski, Wlodzimierz, E-mail: baodingcaoshuo@163.com, E-mail: panyu@cqupt.edu.cn, E-mail: biesiada@us.edu.pl, E-mail: godlowski@uni.opole.pl, E-mail: zhuzh@bnu.edu.cn [Institute of Physics, Opole University, Oleska 48, 45-052 Opole (Poland)

    2012-03-01

    Strong lensing has developed into an important astrophysical tool for probing both cosmology and galaxies (their structure, formation, and evolution). Using the gravitational lensing theory and cluster mass distribution model, we try to collect a relatively complete observational data concerning the Hubble constant independent ratio between two angular diameter distances D{sub ds}/D{sub s} from various large systematic gravitational lens surveys and lensing by galaxy clusters combined with X-ray observations, and check the possibility to use it in the future as complementary to other cosmological probes. On one hand, strongly gravitationally lensed quasar-galaxy systems create such a new opportunity by combining stellar kinematics (central velocity dispersion measurements) with lensing geometry (Einstein radius determination from position of images). We apply such a method to a combined gravitational lens data set including 70 data points from Sloan Lens ACS (SLACS) and Lens Structure and Dynamics survey (LSD). On the other hand, a new sample of 10 lensing galaxy clusters with redshifts ranging from 0.1 to 0.6 carefully selected from strong gravitational lensing systems with both X-ray satellite observations and optical giant luminous arcs, is also used to constrain three dark energy models (ΛCDM, constant w and CPL) under a flat universe assumption. For the full sample (n = 80) and the restricted sample (n = 46) including 36 two-image lenses and 10 strong lensing arcs, we obtain relatively good fitting values of basic cosmological parameters, which generally agree with the results already known in the literature. This results encourages further development of this method and its use on larger samples obtained in the future.

  15. Lenses in the forest: cross correlation of the Lyman-alpha flux with cosmic microwave background lensing.

    Science.gov (United States)

    Vallinotto, Alberto; Das, Sudeep; Spergel, David N; Viel, Matteo

    2009-08-28

    We present a theoretical estimate for a new observable: the cross correlation between the Lyman-alpha flux fluctuations in quasar spectra and the convergence of the cosmic microwave background as measured along the same line of sight. As a first step toward the assessment of its detectability, we estimate the signal-to-noise ratio using linear theory. Although the signal-to-noise is small for a single line of sight and peaks at somewhat smaller redshifts than those probed by the Lyman-alpha forest, we estimate a total signal-to-noise of 9 for cross correlating quasar spectra of SDSS-III with Planck and 20 for cross correlating with a future polarization based cosmic microwave background experiment. The detection of this effect would be a direct measure of the neutral hydrogen-matter cross correlation and could provide important information on the growth of structures at large scales in a redshift range which is still poorly probed.

  16. Finding strong lenses in CFHTLS using convolutional neural networks

    Science.gov (United States)

    Jacobs, C.; Glazebrook, K.; Collett, T.; More, A.; McCarthy, C.

    2017-10-01

    We train and apply convolutional neural networks, a machine learning technique developed to learn from and classify image data, to Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) imaging for the identification of potential strong lensing systems. An ensemble of four convolutional neural networks was trained on images of simulated galaxy-galaxy lenses. The training sets consisted of a total of 62 406 simulated lenses and 64 673 non-lens negative examples generated with two different methodologies. An ensemble of trained networks was applied to all of the 171 deg2 of the CFHTLS wide field image data, identifying 18 861 candidates including 63 known and 139 other potential lens candidates. A second search of 1.4 million early-type galaxies selected from the survey catalogue as potential deflectors, identified 2465 candidates including 117 previously known lens candidates, 29 confirmed lenses/high-quality lens candidates, 266 novel probable or potential lenses and 2097 candidates we classify as false positives. For the catalogue-based search we estimate a completeness of 21-28 per cent with respect to detectable lenses and a purity of 15 per cent, with a false-positive rate of 1 in 671 images tested. We predict a human astronomer reviewing candidates produced by the system would identify 20 probable lenses and 100 possible lenses per hour in a sample selected by the robot. Convolutional neural networks are therefore a promising tool for use in the search for lenses in current and forthcoming surveys such as the Dark Energy Survey and the Large Synoptic Survey Telescope.

  17. Analysis of luminosity distributions of strong lensing galaxies: subtraction of diffuse lensed signal

    Science.gov (United States)

    Biernaux, J.; Magain, P.; Hauret, C.

    2017-08-01

    Context. Strong gravitational lensing gives access to the total mass distribution of galaxies. It can unveil a great deal of information about the lenses' dark matter content when combined with the study of the lenses' light profile. However, gravitational lensing galaxies, by definition, appear surrounded by lensed signal, both point-like and diffuse, that is irrelevant to the lens flux. Therefore, the observer is most often restricted to studying the innermost portions of the galaxy, where classical fitting methods show some instabilities. Aims: We aim at subtracting that lensed signal and at characterising some lenses' light profile by computing their shape parameters (half-light radius, ellipticity, and position angle). Our objective is to evaluate the total integrated flux in an aperture the size of the Einstein ring in order to obtain a robust estimate of the quantity of ordinary (luminous) matter in each system. Methods: We are expanding the work we started in a previous paper that consisted in subtracting point-like lensed images and in independently measuring each shape parameter. We improve it by designing a subtraction of the diffuse lensed signal, based only on one simple hypothesis of symmetry. We apply it to the cases where it proves to be necessary. This extra step improves our study of the shape parameters and we refine it even more by upgrading our half-light radius measurement method. We also calculate the impact of our specific image processing on the error bars. Results: The diffuse lensed signal subtraction makes it possible to study a larger portion of relevant galactic flux, as the radius of the fitting region increases by on average 17%. We retrieve new half-light radii values that are on average 11% smaller than in our previous work, although the uncertainties overlap in most cases. This shows that not taking the diffuse lensed signal into account may lead to a significant overestimate of the half-light radius. We are also able to measure

  18. Strong lensing of gravitational waves as seen by LISA.

    Science.gov (United States)

    Sereno, M; Sesana, A; Bleuler, A; Jetzer, Ph; Volonteri, M; Begelman, M C

    2010-12-17

    We discuss strong gravitational lensing of gravitational waves from the merging of massive black hole binaries in the context of the LISA mission. Detection of multiple events would provide invaluable information on competing theories of gravity, evolution and formation of structures and, possibly, constraints on H0 and other cosmological parameters. Most of the optical depth for lensing is provided by intervening massive galactic halos, for which wave optics effects are negligible. Probabilities to observe multiple events are sizable for a broad range of formation histories. For the most optimistic models, up to ≲ 4 multiple events with a signal to noise ratio ≳ 8 are expected in a 5-year mission. Chances are significant even for conservative models with either light (≲ 60%) or heavy (≲ 40%) seeds. Because of lensing amplification, some intrinsically too faint signals are brought over threshold (≲ 2 per year).

  19. Strong deflection gravitational lensing by a modified Hayward black hole

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Shan-Shan; Xie, Yi [Nanjing University, School of Astronomy and Space Science, Nanjing (China); Nanjing University, Ministry of Education, Key Laboratory of Modern Astronomy and Astrophysics, Nanjing (China)

    2017-05-15

    A modified Hayward black hole is a nonsingular black hole. It is proposed that it would form when the pressure generated by quantum gravity can stop matter's collapse as the matter reaches the Planck density. Strong deflection gravitational lensing occurring nearby its event horizon might provide some clues of these quantum effects in its central core. We investigate observables of the strong deflection lensing, including angular separations, brightness differences and time delays between its relativistic images, and we estimate their values for the supermassive black hole in the Galactic center. We find that it is possible to distinguish the modified Hayward black hole from a Schwarzschild one, but it demands a very high resolution, beyond current stage. (orig.)

  20. Strong field gravitational lensing by a charged Galileon black hole

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Shan-Shan; Xie, Yi, E-mail: clefairy035@163.com, E-mail: yixie@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China)

    2016-07-01

    Strong field gravitational lensings are dramatically disparate from those in the weak field by representing relativistic images due to light winds one to infinity loops around a lens before escaping. We study such a lensing caused by a charged Galileon black hole, which is expected to have possibility to evade no-hair theorem. We calculate the angular separations and time delays between different relativistic images of the charged Galileon black hole. All these observables can potentially be used to discriminate a charged Galileon black hole from others. We estimate the magnitudes of these observables for the closest supermassive black hole Sgr A*. The strong field lensing observables of the charged Galileon black hole can be close to those of a tidal Reissner-Nordström black hole or those of a Reissner-Nordström black hole. It will be helpful to distinguish these black holes if we can separate the outermost relativistic images and determine their angular separation, brightness difference and time delay, although it requires techniques beyond the current limit.

  1. Discovery of a Very Bright Strongly Lensed Galaxy Candidate at z ≈ 7.6

    Science.gov (United States)

    Bradley, L. D.; Bouwens, R. J.; Ford, H. C.; Illingworth, G. D.; Jee, M. J.; Benítez, N.; Broadhurst, T. J.; Franx, M.; Frye, B. L.; Infante, L.; Motta, V.; Rosati, P.; White, R. L.; Zheng, W.

    2008-05-01

    Using Hubble Space Telescope (HST) and Spitzer IRAC imaging, we report the discovery of a very bright strongly lensed Lyman break galaxy (LBG) candidate at z ~ 7.6 in the field of the massive galaxy cluster Abell 1689 (z = 0.18). The galaxy candidate, which we refer to as A1689-zD1, shows a strong z850 - J110 break of at least 2.2 mag and is completely undetected (= 25). A1689-zD1 has an observed (lensed) magnitude of 24.7 AB (8 σ) in the NICMOS H160 band and is ~1.3 mag brighter than the brightest known z850-dropout galaxy. When corrected for the cluster magnification of ~9.3 at z ~ 7.6, the candidate has an intrinsic magnitude of H160 = 27.1 AB, or about an L* galaxy at z ~ 7.6. The source-plane deprojection shows that the star formation is occurring in compact knots of size lesssim300 pc. The best-fit stellar population synthesis models yield a median redshift of 7.6, stellar masses (1.6-3.9) × 109 M⊙, stellar ages 45-320 Myr, star formation rates lesssim7.6 M⊙ yr-1, and low reddening with AV 7.0 galaxy candidate found to date. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy under NASA contract NAS5-26555. Based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407.

  2. Simulation-based marginal likelihood for cluster strong lensing cosmology

    Science.gov (United States)

    Killedar, M.; Borgani, S.; Fabjan, D.; Dolag, K.; Granato, G.; Meneghetti, M.; Planelles, S.; Ragone-Figueroa, C.

    2018-01-01

    Comparisons between observed and predicted strong lensing properties of galaxy clusters have been routinely used to claim either tension or consistency with Λ cold dark matter cosmology. However, standard approaches to such cosmological tests are unable to quantify the preference for one cosmology over another. We advocate approximating the relevant Bayes factor using a marginal likelihood that is based on the following summary statistic: the posterior probability distribution function for the parameters of the scaling relation between Einstein radii and cluster mass, α and β. We demonstrate, for the first time, a method of estimating the marginal likelihood using the X-ray selected z > 0.5 Massive Cluster Survey clusters as a case in point and employing both N-body and hydrodynamic simulations of clusters. We investigate the uncertainty in this estimate and consequential ability to compare competing cosmologies, which arises from incomplete descriptions of baryonic processes, discrepancies in cluster selection criteria, redshift distribution and dynamical state. The relation between triaxial cluster masses at various overdensities provides a promising alternative to the strong lensing test.

  3. Cusp-core problem and strong gravitational lensing

    International Nuclear Information System (INIS)

    Li Nan; Chen Daming

    2009-01-01

    Cosmological numerical simulations of galaxy formation have led to the cuspy density profile of a pure cold dark matter halo toward the center, which is in sharp contradiction with the observations of the rotation curves of cold dark matter-dominated dwarf and low surface brightness disk galaxies, with the latter tending to favor mass profiles with a flat central core. Many efforts have been devoted to resolving this cusp-core problem in recent years, among them, baryon-cold dark matter interactions are considered to be the main physical mechanisms erasing the cold dark matter (CDM) cusp into a flat core in the centers of all CDM halos. Clearly, baryon-cold dark matter interactions are not customized only for CDM-dominated disk galaxies, but for all types, including giant ellipticals. We first fit the most recent high resolution observations of rotation curves with the Burkert profile, then use the constrained core size-halo mass relation to calculate the lensing frequency, and compare the predicted results with strong lensing observations. Unfortunately, it turns out that the core size constrained from rotation curves of disk galaxies cannot be extrapolated to giant ellipticals. We conclude that, in the standard cosmological paradigm, baryon-cold dark matter interactions are not universal mechanisms for galaxy formation, and therefore, they cannot be true solutions to the cusp-core problem.

  4. CLASH: THREE STRONGLY LENSED IMAGES OF A CANDIDATE z Almost-Equal-To 11 GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Coe, Dan; Postman, Marc; Bradley, Larry; Koekemoer, Anton [Space Telescope Science Institute, Baltimore, MD (United States); Zitrin, Adi; Carrasco, Mauricio [Institut fuer Theoretische Astrophysik, Zentrum fuer Astronomie, Institut fuer Theoretische Astrophysik, Albert-Ueberle-Str. 2, D-29120 Heidelberg (Germany); Shu, Xinwen [Department of Astronomy, University of Science and Technology of China, Hefei (China); Zheng, Wei; Ford, Holland; Rodney, Steven A. [Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD (United States); Bouwens, Rychard [Leiden Observatory, Leiden University, NL-2333 Leiden (Netherlands); Broadhurst, Tom [Department of Theoretical Physics, University of the Basque Country UPV/EHU, E-48080 Bilbao (Spain); Monna, Anna [Instituts fuer Astronomie und Astrophysik, Universitaes-Sternwarte Muenchen, D-81679 Muenchen (Germany); Host, Ole; Jouvel, Stephanie [Department of Physics and Astronomy, University College London, London (United Kingdom); Moustakas, Leonidas A. [Jet Propulsion Laboratory, California Institute of Technology, La Canada Flintridge, CA (United States); Moustakas, John [Department of Physics and Astronomy, Siena College, Loudonville, NY (United States); Van der Wel, Arjen [Max-Planck-Institut fuer Astronomie (MPIA), D-69117 Heidelberg (Germany); Donahue, Megan [Department of Physics and Astronomy, Michigan State University, East Lansing, MI (United States); Benitez, Narciso, E-mail: DCoe@STScI.edu [Instituto de Astrofisica de Andalucia (IAA-CSIC), E-18008 Granada (Spain); and others

    2013-01-01

    We present a candidate for the most distant galaxy known to date with a photometric redshift of z = 10.7{sup +0.6} {sub -0.4} (95% confidence limits; with z < 9.5 galaxies of known types ruled out at 7.2{sigma}). This J-dropout Lyman break galaxy, named MACS0647-JD, was discovered as part of the Cluster Lensing and Supernova survey with Hubble (CLASH). We observe three magnified images of this galaxy due to strong gravitational lensing by the galaxy cluster MACSJ0647.7+7015 at z = 0.591. The images are magnified by factors of {approx}80, 7, and 2, with the brighter two observed at {approx}26th magnitude AB ({approx}0.15 {mu}Jy) in the WFC3/IR F160W filter ({approx}1.4-1.7 {mu}m) where they are detected at {approx}>12{sigma}. All three images are also confidently detected at {approx}>6{sigma} in F140W ({approx}1.2-1.6 {mu}m), dropping out of detection from 15 lower wavelength Hubble Space Telescope filters ({approx}0.2-1.4 {mu}m), and lacking bright detections in Spitzer/IRAC 3.6 {mu}m and 4.5 {mu}m imaging ({approx}3.2-5.0 {mu}m). We rule out a broad range of possible lower redshift interlopers, including some previously published as high-redshift candidates. Our high-redshift conclusion is more conservative than if we had neglected a Bayesian photometric redshift prior. Given CLASH observations of 17 high-mass clusters to date, our discoveries of MACS0647-JD at z {approx} 10.8 and MACS1149-JD at z {approx} 9.6 are consistent with a lensed luminosity function extrapolated from lower redshifts. This would suggest that low-luminosity galaxies could have reionized the universe. However, given the significant uncertainties based on only two galaxies, we cannot yet rule out the sharp drop-off in number counts at z {approx}> 10 suggested by field searches.

  5. Power spectrum of dark matter substructure in strong gravitational lenses

    Science.gov (United States)

    Diaz Rivero, Ana; Cyr-Racine, Francis-Yan; Dvorkin, Cora

    2018-01-01

    Studying the smallest self-bound dark matter structure in our Universe can yield important clues about the fundamental particle nature of dark matter. Galaxy-scale strong gravitational lensing provides a unique way to detect and characterize dark matter substructures at cosmological distances from the Milky Way. Within the cold dark matter (CDM) paradigm, the number of low-mass subhalos within lens galaxies is expected to be large, implying that their contribution to the lensing convergence field is approximately Gaussian and could thus be described by their power spectrum. We develop here a general formalism to compute from first principles the substructure convergence power spectrum for different populations of dark matter subhalos. As an example, we apply our framework to two distinct subhalo populations: a truncated Navarro-Frenk-White subhalo population motivated by standard CDM, and a truncated cored subhalo population motivated by self-interacting dark matter (SIDM). We study in detail how the subhalo abundance, mass function, internal density profile, and concentration affect the amplitude and shape of the substructure power spectrum. We determine that the power spectrum is mostly sensitive to a specific combination of the subhalo abundance and moments of the mass function, as well as to the average tidal truncation scale of the largest subhalos included in the analysis. Interestingly, we show that the asymptotic slope of the substructure power spectrum at large wave number reflects the internal density profile of the subhalos. In particular, the SIDM power spectrum exhibits a characteristic steepening at large wave number absent in the CDM power spectrum, opening the possibility of using this observable, if at all measurable, to discern between these two scenarios.

  6. Strong gravitational lensing by a charged Kiselev black hole

    Energy Technology Data Exchange (ETDEWEB)

    Azreg-Ainou, Mustapha [Baskent University, Engineering Faculty, Ankara (Turkey); Bahamonde, Sebastian [University College London, Department of Mathematics, London (United Kingdom); Jamil, Mubasher [National University of Sciences and Technology (NUST), Department of Mathematics, School of Natural Sciences (SNS), Islamabad (Pakistan)

    2017-06-15

    We study the gravitational lensing scenario where the lens is a spherically symmetric charged black hole (BH) surrounded by quintessence matter. The null geodesic equations in the curved background of the black hole are derived. The resulting trajectory equation is solved analytically via perturbation and series methods for a special choice of parameters, and the distance of the closest approach to black hole is calculated. We also derive the lens equation giving the bending angle of light in the curved background. In the strong field approximation, the solution of the lens equation is also obtained for all values of the quintessence parameter w{sub q}. For all w{sub q}, we show that there are no stable closed null orbits and that corrections to the deflection angle for the Reissner-Nordstroem black hole when the observer and the source are at large, but finite, distances from the lens do not depend on the charge up to the inverse of the distances squared. A part of the present work, analyzed, however, with a different approach, is the extension of Younas et al. (Phys Rev D 92:084042, 2015) where the uncharged case has been treated. (orig.)

  7. THE EFFECT OF ENVIRONMENT ON SHEAR IN STRONG GRAVITATIONAL LENSES

    International Nuclear Information System (INIS)

    Wong, Kenneth C.; Zabludoff, Ann I.; Keeton, Charles R.; Williams, Kurtis A.; Momcheva, Ivelina G.

    2011-01-01

    Using new photometric and spectroscopic data in the fields of nine strong gravitational lenses that lie in galaxy groups, we analyze the effects of both the local group environment and line-of-sight (LOS) galaxies on the lens potential. We use Monte Carlo simulations to derive the shear directly from measurements of the complex lens environment, providing the first detailed independent check of the shear obtained from lens modeling. We account for possible tidal stripping of the group galaxies by varying the fraction of total mass apportioned between the group dark matter halo and individual group galaxies. The environment produces an average shear of γ = 0.08 (ranging from 0.02 to 0.17), significant enough to affect quantities derived from lens observables. However, the direction and magnitude of the shears do not match those obtained from lens modeling in three of the six four-image systems in our sample (B1422, RXJ1131, and WFI2033). The source of this disagreement is not clear, implying that the assumptions inherent in both the environment and lens model approaches must be reconsidered. If only the local group environment of the lens is included, the average shear is γ = 0.05 (ranging from 0.01 to 0.14), indicating that LOS contributions to the lens potential are not negligible. We isolate the effects of various theoretical and observational uncertainties on our results. Of those uncertainties, the scatter in the Faber-Jackson relation and error in the group centroid position dominate. Future surveys of lens environments should prioritize spectroscopic sampling of both the local lens environment and objects along the LOS, particularly those bright (I< 21.5) galaxies projected within 5' of the lens.

  8. The Initial Mass Function in the Nearest Strong Lenses from SNELLS: Assessing the Consistency of Lensing, Dynamical, and Spectroscopic Constraints

    Energy Technology Data Exchange (ETDEWEB)

    Newman, Andrew B. [The Observatories of the Carnegie Institution for Science, Pasadena, CA (United States); Smith, Russell J. [Centre for Extragalactic Astronomy, University of Durham, South Road, Durham (United Kingdom); Conroy, Charlie [Department of Astronomy, Harvard University, Cambridge, MA (United States); Villaume, Alexa [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA (United States); Van Dokkum, Pieter, E-mail: anewman@obs.carnegiescience.edu [Department of Astrophysical Sciences, Yale University, New Haven, CT (United States)

    2017-08-20

    We present new observations of the three nearest early-type galaxy (ETG) strong lenses discovered in the SINFONI Nearby Elliptical Lens Locator Survey (SNELLS). Based on their lensing masses, these ETGs were inferred to have a stellar initial mass function (IMF) consistent with that of the Milky Way, not the bottom-heavy IMF that has been reported as typical for high- σ ETGs based on lensing, dynamical, and stellar population synthesis techniques. We use these unique systems to test the consistency of IMF estimates derived from different methods. We first estimate the stellar M {sub *}/ L using lensing and stellar dynamics. We then fit high-quality optical spectra of the lenses using an updated version of the stellar population synthesis models developed by Conroy and van Dokkum. When examined individually, we find good agreement among these methods for one galaxy. The other two galaxies show 2–3 σ tension with lensing estimates, depending on the dark matter contribution, when considering IMFs that extend to 0.08 M {sub ⊙}. Allowing a variable low-mass cutoff or a nonparametric form of the IMF reduces the tension among the IMF estimates to <2 σ . There is moderate evidence for a reduced number of low-mass stars in the SNELLS spectra, but no such evidence in a composite spectrum of matched- σ ETGs drawn from the SDSS. Such variation in the form of the IMF at low stellar masses ( m ≲ 0.3 M {sub ⊙}), if present, could reconcile lensing/dynamical and spectroscopic IMF estimates for the SNELLS lenses and account for their lighter M {sub *}/ L relative to the mean matched- σ ETG. We provide the spectra used in this study to facilitate future comparisons.

  9. The SDSS Discovery of a Strongly Lensed Post-Starburst Galaxy at z=0.766

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Min-Su; Strauss, Michael A.; Oguri, Masamune; Inada, Naohisa; Falco, Emilio E.; Broadhurst, Tom; Gunn, James E.

    2008-09-30

    We present the first result of a survey for strong galaxy-galaxy lenses in Sloan Digital Sky Survey (SDSS) images. SDSS J082728.70+223256.4 was selected as a lensing candidate using selection criteria based on the color and positions of objects in the SDSS photometric catalog. Follow-up imaging and spectroscopy showed this object to be a lensing system. The lensing galaxy is an elliptical at z = 0.349 in a galaxy cluster. The lensed galaxy has the spectrum of a post-starburst galaxy at z = 0.766. The lensing galaxy has an estimated mass of {approx} 1.2 x 10{sup 12} M{sub {circle_dot}} and the corresponding mass to light ratio in the B-band is {approx} 26 M{sub {circle_dot}}/L{sub {circle_dot}} inside 1.1 effective radii of the lensing galaxy. Our study shows how catalogs drawn from multi-band surveys can be used to find strong galaxy-galaxy lenses having multiple lens images. Our strong lensing candidate selection based on photometry-only catalogs will be useful in future multi-band imaging surveys such as SNAP and LSST.

  10. GEMINI/GMOS SPECTROSCOPY OF 26 STRONG-LENSING-SELECTED GALAXY CLUSTER CORES

    International Nuclear Information System (INIS)

    Bayliss, Matthew B.; Gladders, Michael D.; Koester, Benjamin P.; Hennawi, Joseph F.; Sharon, Keren; Dahle, Haakon; Oguri, Masamune

    2011-01-01

    We present results from a spectroscopic program targeting 26 strong-lensing cluster cores that were visually identified in the Sloan Digital Sky Survey (SDSS) and the Second Red-Sequence Cluster Survey (RCS-2). The 26 galaxy cluster lenses span a redshift range of 0.2 Vir = 7.84 x 10 14 M sun h -1 0.7 , which is somewhat higher than predictions for strong-lensing-selected clusters in simulations. The disagreement is not significant considering the large uncertainty in our dynamical data, systematic uncertainties in the velocity dispersion calibration, and limitations of the theoretical modeling. Nevertheless our study represents an important first step toward characterizing large samples of clusters that are identified in a systematic way as systems exhibiting dramatic strong-lensing features.

  11. On the Contribution of Large-Scale Structure to Strong Gravitational Lensing

    Science.gov (United States)

    Faure, C.; Kneib, J.-P.; Hilbert, S.; Massey, R.; Covone, G.; Finoguenov, A.; Leauthaud, A.; Taylor, J. E.; Pires, S.; Scoville, N.; Koekemoer, Anton M.

    2009-04-01

    We study the correlation between the locations of galaxy-galaxy strong-lensing candidates and tracers of large-scale structure from both weak lensing (WL) or X-ray emission. The Cosmological Evolution Survey (COSMOS) is a unique data set, combining deep, high resolution and contiguous imaging in which strong lenses have been discovered, plus unparalleled multiwavelength coverage. To help interpret the COSMOS data, we have also produced mock COSMOS strong- and WL observations, based on ray-tracing through the Millennium Simulation. In agreement with the simulations, we find that strongly lensed images with the largest angular separations are found in the densest regions of the COSMOS field. This is explained by a prevalence among the lens population in dense environments of elliptical galaxies with high total-to-stellar mass ratios, which can deflect light through larger angles. However, we also find that the overall fraction of elliptical galaxies with strong gravitational lensing is independent of the local mass density; this observation is not true of the simulations, which predict an increasing fraction of strong lenses in dense environments. The discrepancy may be a real effect, but could also be explained by various limitations of our analysis. For example, our visual search of strong lens systems could be incomplete and suffer from selection bias; the luminosity function of elliptical galaxies may differ between our real and simulated data; or the simplifying assumptions and approximations used in our lensing simulations may be inadequate. Work is therefore ongoing. Automated searches for strong lens systems will be particularly important in better constraining the selection function.

  12. Relationship between high-energy absorption cross section and strong gravitational lensing for black hole

    International Nuclear Information System (INIS)

    Wei Shaowen; Liu Yuxiao; Guo Heng

    2011-01-01

    In this paper, we obtain a relation between the high-energy absorption cross section and the strong gravitational lensing for a static and spherically symmetric black hole. It provides us a possible way to measure the high-energy absorption cross section for a black hole from strong gravitational lensing through astronomical observation. More importantly, it allows us to compute the total energy emission rate for high-energy particles emitted from the black hole acting as a gravitational lens. It could tell us the range of the frequency, among which the black hole emits the most of its energy and the gravitational waves are most likely to be observed. We also apply it to the Janis-Newman-Winicour solution. The results suggest that we can test the cosmic censorship hypothesis through the observation of gravitational lensing by the weakly naked singularities acting as gravitational lenses.

  13. Speed of Gravitational Waves from Strongly Lensed Gravitational Waves and Electromagnetic Signals.

    Science.gov (United States)

    Fan, Xi-Long; Liao, Kai; Biesiada, Marek; Piórkowska-Kurpas, Aleksandra; Zhu, Zong-Hong

    2017-03-03

    We propose a new model-independent measurement strategy for the propagation speed of gravitational waves (GWs) based on strongly lensed GWs and their electromagnetic (EM) counterparts. This can be done in two ways: by comparing arrival times of GWs and their EM counterparts and by comparing the time delays between images seen in GWs and their EM counterparts. The lensed GW-EM event is perhaps the best way to identify an EM counterpart. Conceptually, this method does not rely on any specific theory of massive gravitons or modified gravity. Its differential setting (i.e., measuring the difference between time delays in GW and EM domains) makes it robust against lens modeling details (photons and GWs travel in the same lensing potential) and against internal time delays between GW and EM emission acts. It requires, however, that the theory of gravity is metric and predicts gravitational lensing similar to general relativity. We expect that such a test will become possible in the era of third-generation gravitational-wave detectors, when about 10 lensed GW events would be observed each year. The power of this method is mainly limited by the timing accuracy of the EM counterpart, which for kilonovae is around 10^{4}  s. This uncertainty can be suppressed by a factor of ∼10^{10}, if strongly lensed transients of much shorter duration associated with the GW event can be identified. Candidates for such short transients include short γ-ray bursts and fast radio bursts.

  14. Strong gravitational lensing in f (χ) = χ{sup 3/2} gravity

    Energy Technology Data Exchange (ETDEWEB)

    Campigotto, M.C.; Diaferio, A. [Dipartimento di Fisica, Università di Torino, Via P. Giuria 1, 10125, Torino (Italy); Hernandez, X. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Ciudad de Mexico 04510 (Mexico); Fatibene, L., E-mail: martacostanza.campigotto@to.infn.it, E-mail: antonaldo.diaferio@unito.it, E-mail: xavier@astro.unam.mx, E-mail: lorenzo.fatibene@unito.it [Dipartimento di Matematica, Università di Torino, Via C. Alberto 10, 10123, Torino (Italy)

    2017-06-01

    We discuss the phenomenology of gravitational lensing in the purely metric f (χ) gravity, an f ( R ) gravity where the action of the gravitational field depends on the source mass. We focus on the strong lensing regime in galaxy-galaxy lens systems and in clusters of galaxies. By adopting point-like lenses and using an approximate metric solution accurate to second order of the velocity field v / c , we show how, in the f (χ) = χ{sup 3/2} gravity, the same light deflection can be produced by lenses with masses smaller than in General Relativity (GR); this mass difference increases with increasing impact parameter and decreasing lens mass. However, for sufficiently massive point-like lenses and small impact parameters, f (χ) = χ{sup 3/2} and GR yield indistinguishable light deflection angles: this regime occurs both in observed galaxy-galaxy lens systems and in the central regions of galaxy clusters. In the former systems, the GR and f (χ) masses are compatible with the mass of standard stellar populations and little or no dark matter, whereas, on the scales of the core of galaxy clusters, the presence of substantial dark matter is required by our point-like lenses both in GR and in our approximate f (χ) = χ{sup 3/2} solution. We thus conclude that our approximate metric solution of f (χ) = χ{sup 3/2} is unable to describe the observed phenomenology of the strong lensing regime without the aid of dark matter.

  15. Radio and Gamma-Ray Monitoring of Strongly Lensed Quasars and Blazars

    NARCIS (Netherlands)

    Rumbaugh, Nick; Fassnacht, Chris; McKean, John; Koopmans, Leon; Auger, Matthew; Suyu, Sherry; Marshall, Philip J.

    2015-01-01

    We observed six strongly lensed, radio-loud quasars (MG 0414+0534, CLASS B0712+472, JVAS B1030+074, CLASS B1127+385, CLASS B1152+199, and JVAS B1938+666) in order to identify systems suitable for measuring cosmological parameters using time delays between their multiple images. Two separate

  16. Serendipitous discovery of a strong-lensed galaxy in integral field spectroscopy from MUSE

    Science.gov (United States)

    Galbany, Lluís; Collett, Thomas E.; Méndez-Abreu, Jairo; Sánchez, Sebastián F.; Anderson, Joseph P.; Kuncarayakti, Hanindyo

    2018-06-01

    2MASX J04035024-0239275 is a bright red elliptical galaxy at redshift 0.0661 that presents two extended sources at 2″ to the north-east and 1″ to the south-west. The sizes and surface brightnesses of the two blue sources are consistent with a gravitationally-lensed background galaxy. In this paper we present MUSE observations of this galaxy from the All-weather MUse Supernova Integral-field Nearby Galaxies (AMUSING) survey, and report the discovery of a background lensed galaxy at redshift 0.1915, together with other 15 background galaxies at redshifts ranging from 0.09 to 0.9, that are not multiply imaged. We have extracted aperture spectra of the lens and all the sources and fit the stellar continuum with STARLIGHT to estimate their stellar and emission line properties. A trace of past merger and active nucleus activity is found in the lensing galaxy, while the background lensed galaxy is found to be star-forming. Modeling the lensing potential with a singular isothermal ellipsoid, we find an Einstein radius of 1."45±0."04, which corresponds to 1.9 kpc at the redshift of the lens and it is much smaller than its effective radius (reff ˜ 9″"). Comparing the Einstein mass and the STARLIGHT stellar mass within the same aperture yields a dark matter fraction of 18% ± 8 % within the Einstein radius. The advent of large surveys such as the Large Synoptic Survey Telescope (LSST) will discover a number of strong-lensed systems, and here we demonstrate how wide-field integral field spectroscopy offers an excellent approach to study them and to precisely model lensing effects.

  17. HERSCHEL-ATLAS: TOWARD A SAMPLE OF {approx}1000 STRONGLY LENSED GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Nuevo, J.; Lapi, A.; Bressan, S.; Danese, L.; De Zotti, G.; Cai, Z.-Y.; Fan, L. [SISSA, Via Bonomea 265, I-34136 Trieste (Italy); Fleuren, S.; Sutherland, W. [School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Negrello, M. [Department of Physical Sciences, Open University, Milton Keynes MK7 6AA (United Kingdom); Baes, M. [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Baker, A. J. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854-8019 (United States); Clements, D. L. [Astrophysics Group, Imperial College, Blackett Lab, Prince Consort Road, London SW7 2AZ (United Kingdom); Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Dannerbauer, H. [Institut fuer Astronomie, Universitaet Wien, Tuerkenschanzstrasse 17, 1180 Wien, Oesterreich (Austria); Dunne, L.; Dye, S. [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Eales, S. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA (United Kingdom); Frayer, D. T. [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States); Harris, A. I., E-mail: gnuevo@sissa.it [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); and others

    2012-04-10

    While the selection of strongly lensed galaxies (SLGs) with 500 {mu}m flux density S{sub 500} > 100 mJy has proven to be rather straightforward, for many applications it is important to analyze samples larger than the ones obtained when confining ourselves to such a bright limit. Moreover, only by probing to fainter flux densities is it possible to exploit strong lensing to investigate the bulk of the high-z star-forming galaxy population. We describe HALOS (the Herschel-ATLAS Lensed Objects Selection), a method for efficiently selecting fainter candidate SLGs, reaching a surface density of {approx_equal} 1.5-2 deg{sup -2}, i.e., a factor of about 4-6 higher than that at the 100 mJy flux limit. HALOS will allow the selection of up to {approx}1000 candidate SLGs (with amplifications {mu} {approx}> 2) over the full H-ATLAS survey area. Applying HALOS to the H-ATLAS Science Demonstration Phase field ({approx_equal} 14.4 deg{sup 2}) we find 31 candidate SLGs, whose candidate lenses are identified in the VIKING near-infrared catalog. Using the available information on candidate sources and candidate lenses we tentatively estimate a {approx_equal} 72% purity of the sample. As expected, the purity decreases with decreasing flux density of the sources and with increasing angular separation between candidate sources and lenses. The redshift distribution of the candidate lensed sources is close to that reported for most previous surveys for lensed galaxies, while that of candidate lenses extends to redshifts substantially higher than found in the other surveys. The counts of candidate SLGs are also in good agreement with model predictions. Even though a key ingredient of the method is the deep near-infrared VIKING photometry, we show that H-ATLAS data alone allow the selection of a similarly deep sample of candidate SLGs with an efficiency close to 50%; a slightly lower surface density ({approx_equal} 1.45 deg{sup -2}) can be reached with a {approx}70% efficiency.

  18. A Robust Mass Estimator for Dark Matter Subhalo Perturbations in Strong Gravitational Lenses

    Energy Technology Data Exchange (ETDEWEB)

    Minor, Quinn E. [Department of Science, Borough of Manhattan Community College, City University of New York, New York, NY 10007 (United States); Kaplinghat, Manoj [Department of Physics and Astronomy, University of California, Irvine CA 92697 (United States); Li, Nan [Department of Astronomy and Astrophysics, The University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States)

    2017-08-20

    A few dark matter substructures have recently been detected in strong gravitational lenses through their perturbations of highly magnified images. We derive a characteristic scale for lensing perturbations and show that they are significantly larger than the perturber’s Einstein radius. We show that the perturber’s projected mass enclosed within this radius, scaled by the log-slope of the host galaxy’s density profile, can be robustly inferred even if the inferred density profile and tidal radius of the perturber are biased. We demonstrate the validity of our analytic derivation using several gravitational lens simulations where the tidal radii and the inner log-slopes of the density profile of the perturbing subhalo are allowed to vary. By modeling these simulated data, we find that our mass estimator, which we call the effective subhalo lensing mass, is accurate to within about 10% or smaller in each case, whereas the inferred total subhalo mass can potentially be biased by nearly an order of magnitude. We therefore recommend that the effective subhalo lensing mass be reported in future lensing reconstructions, as this will allow for a more accurate comparison with the results of dark matter simulations.

  19. Strongly lensed neutral hydrogen emission: detection predictions with current and future radio interferometers

    Science.gov (United States)

    Deane, R. P.; Obreschkow, D.; Heywood, I.

    2015-09-01

    Strong gravitational lensing provides some of the deepest views of the Universe, enabling studies of high-redshift galaxies only possible with next-generation facilities without the lensing phenomenon. To date, 21-cm radio emission from neutral hydrogen has only been detected directly out to z ˜ 0.2, limited by the sensitivity and instantaneous bandwidth of current radio telescopes. We discuss how current and future radio interferometers such as the Square Kilometre Array (SKA) will detect lensed H I emission in individual galaxies at high redshift. Our calculations rely on a semi-analytic galaxy simulation with realistic H I discs (by size, density profile and rotation), in a cosmological context, combined with general relativistic ray tracing. Wide-field, blind H I surveys with the SKA are predicted to be efficient at discovering lensed H I systems, increasingly so at z ≳ 2. This will be enabled by the combination of the magnification boosts, the steepness of the H I luminosity function at the high-mass end, and the fact that the H I spectral line is relatively isolated in frequency. These surveys will simultaneously provide a new technique for foreground lens selection and yield the highest redshift H I emission detections. More near term (and existing) cm-wave facilities will push the high-redshift H I envelope through targeted surveys of known lenses.

  20. What if LIGO's gravitational wave detections are strongly lensed by massive galaxy clusters?

    Science.gov (United States)

    Smith, Graham P.; Jauzac, Mathilde; Veitch, John; Farr, Will M.; Massey, Richard; Richard, Johan

    2018-04-01

    Motivated by the preponderance of so-called `heavy black holes' in the binary black hole (BBH) gravitational wave (GW) detections to date, and the role that gravitational lensing continues to play in discovering new galaxy populations, we explore the possibility that the GWs are strongly lensed by massive galaxy clusters. For example, if one of the GW sources were actually located at z = 1, then the rest-frame mass of the associated BHs would be reduced by a factor of ˜2. Based on the known populations of BBH GW sources and strong-lensing clusters, we estimate a conservative lower limit on the number of BBH mergers detected per detector year at LIGO/Virgo's current sensitivity that are multiply-imaged, of Rdetect ≃ 10-5 yr-1. This is equivalent to rejecting the hypothesis that one of the BBH GWs detected to date was multiply-imaged at ≲4σ. It is therefore unlikely, but not impossible, that one of the GWs is multiply-imaged. We identify three spectroscopically confirmed strong-lensing clusters with well-constrained mass models within the 90 per cent credible sky localizations of the BBH GWs from LIGO's first observing run. In the event that one of these clusters multiply-imaged one of the BBH GWs, we predict that 20-60 per cent of the putative next appearances of the GWs would be detectable by LIGO, and that they would arrive at Earth within 3yr of first detection.

  1. RELICS: Strong Lens Models for Five Galaxy Clusters from the Reionization Lensing Cluster Survey

    Science.gov (United States)

    Cerny, Catherine; Sharon, Keren; Andrade-Santos, Felipe; Avila, Roberto J.; Bradač, Maruša; Bradley, Larry D.; Carrasco, Daniela; Coe, Dan; Czakon, Nicole G.; Dawson, William A.; Frye, Brenda L.; Hoag, Austin; Huang, Kuang-Han; Johnson, Traci L.; Jones, Christine; Lam, Daniel; Lovisari, Lorenzo; Mainali, Ramesh; Oesch, Pascal A.; Ogaz, Sara; Past, Matthew; Paterno-Mahler, Rachel; Peterson, Avery; Riess, Adam G.; Rodney, Steven A.; Ryan, Russell E.; Salmon, Brett; Sendra-Server, Irene; Stark, Daniel P.; Strolger, Louis-Gregory; Trenti, Michele; Umetsu, Keiichi; Vulcani, Benedetta; Zitrin, Adi

    2018-06-01

    Strong gravitational lensing by galaxy clusters magnifies background galaxies, enhancing our ability to discover statistically significant samples of galaxies at {\\boldsymbol{z}}> 6, in order to constrain the high-redshift galaxy luminosity functions. Here, we present the first five lens models out of the Reionization Lensing Cluster Survey (RELICS) Hubble Treasury Program, based on new HST WFC3/IR and ACS imaging of the clusters RXC J0142.9+4438, Abell 2537, Abell 2163, RXC J2211.7–0349, and ACT-CLJ0102–49151. The derived lensing magnification is essential for estimating the intrinsic properties of high-redshift galaxy candidates, and properly accounting for the survey volume. We report on new spectroscopic redshifts of multiply imaged lensed galaxies behind these clusters, which are used as constraints, and detail our strategy to reduce systematic uncertainties due to lack of spectroscopic information. In addition, we quantify the uncertainty on the lensing magnification due to statistical and systematic errors related to the lens modeling process, and find that in all but one cluster, the magnification is constrained to better than 20% in at least 80% of the field of view, including statistical and systematic uncertainties. The five clusters presented in this paper span the range of masses and redshifts of the clusters in the RELICS program. We find that they exhibit similar strong lensing efficiencies to the clusters targeted by the Hubble Frontier Fields within the WFC3/IR field of view. Outputs of the lens models are made available to the community through the Mikulski Archive for Space Telescopes.

  2. Line-of-sight effects in strong lensing: putting theory into practice

    Energy Technology Data Exchange (ETDEWEB)

    Birrer, Simon; Welschen, Cyril; Amara, Adam; Refregier, Alexandre, E-mail: simon.birrer@phys.ethz.ch, E-mail: cyril.welschen@student.ethz.ch, E-mail: adam.amara@phys.ethz.ch, E-mail: alexandre.refregier@phys.ethz.ch [Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093, Zurich (Switzerland)

    2017-04-01

    We present a simple method to accurately infer line of sight (LOS) integrated lensing effects for galaxy scale strong lens systems through image reconstruction. Our approach enables us to separate weak lensing LOS effects from the main strong lens deflector. We test our method using mock data and show that strong lens systems can be accurate probes of cosmic shear with a precision on the shear terms of ± 0.003 (statistical error) for an HST-like dataset. We apply our formalism to reconstruct the lens COSMOS 0038+4133 and its LOS. In addition, we estimate the LOS properties with a halo-rendering estimate based on the COSMOS field galaxies and a galaxy-halo connection. The two approaches are independent and complementary in their information content. We find that when estimating the convergence at the strong lens system, performing a joint analysis improves the measure by a factor of two compared to a halo model only analysis. Furthermore the constraints of the strong lens reconstruction lead to tighter constraints on the halo masses of the LOS galaxies. Joint constraints of multiple strong lens systems may add valuable information to the galaxy-halo connection and may allow independent weak lensing shear measurement calibrations.

  3. The Sloan Lens ACS Survey. XIII. Discovery of 40 New Galaxy-scale Strong Lenses

    Science.gov (United States)

    Shu, Yiping; Brownstein, Joel R.; Bolton, Adam S.; Koopmans, Léon V. E.; Treu, Tommaso; Montero-Dorta, Antonio D.; Auger, Matthew W.; Czoske, Oliver; Gavazzi, Raphaël; Marshall, Philip J.; Moustakas, Leonidas A.

    2017-12-01

    We present the full sample of 118 galaxy-scale strong-lens candidates in the Sloan Lens ACS (SLACS) Survey for the Masses (S4TM) Survey, which are spectroscopically selected from the final data release of the Sloan Digital Sky Survey. Follow-up Hubble Space Telescope (HST) imaging observations confirm that 40 candidates are definite strong lenses with multiple lensed images. The foreground-lens galaxies are found to be early-type galaxies (ETGs) at redshifts 0.06–0.44, and background sources are emission-line galaxies at redshifts 0.22–1.29. As an extension of the SLACS Survey, the S4TM Survey is the first attempt to preferentially search for strong-lens systems with relatively lower lens masses than those in the pre-existing strong-lens samples. By fitting HST data with a singular isothermal ellipsoid model, we find that the total projected mass within the Einstein radius of the S4TM strong-lens sample ranges from 3 × 1010 M ⊙ to 2 × 1011 M ⊙. In Shu et al., we have derived the total stellar mass of the S4TM lenses to be 5 × 1010 M ⊙ to 1 × 1012 M ⊙. Both the total enclosed mass and stellar mass of the S4TM lenses are on average almost a factor of 2 smaller than those of the SLACS lenses, which also represent the typical mass scales of the current strong-lens samples. The extended mass coverage provided by the S4TM sample can enable a direct test, with the aid of strong lensing, for transitions in scaling relations, kinematic properties, mass structure, and dark-matter content trends of ETGs at intermediate-mass scales as noted in previous studies. Based on observations made with the NASA/ESA Hubble Space Telescope (HST), obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. These observations are associated with HST program #12210.

  4. The Impact of Microlensing on the Standardisation of Strongly Lensed Type Ia Supernovae

    Science.gov (United States)

    Foxley-Marrable, Max; Collett, Thomas E.; Vernardos, Georgios; Goldstein, Daniel A.; Bacon, David

    2018-05-01

    We investigate the effect of microlensing on the standardisation of strongly lensed Type Ia supernovae (GLSNe Ia). We present predictions for the amount of scatter induced by microlensing across a range of plausible strong lens macromodels. We find that lensed images in regions of low convergence, shear and stellar density are standardisable, where the microlensing scatter is ≲ 0.15 magnitudes, comparable to the intrinsic dispersion of for a typical SN Ia. These standardisable configurations correspond to asymmetric lenses with an image located far outside the Einstein radius of the lens. Symmetric and small Einstein radius lenses (≲ 0.5 arcsec) are not standardisable. We apply our model to the recently discovered GLSN Ia iPTF16geu and find that the large discrepancy between the observed flux and the macromodel predictions from More et al. (2017) cannot be explained by microlensing alone. Using the mock GLSNe Ia catalogue of Goldstein et al. (2017), we predict that ˜ 22% of GLSNe Ia discovered by LSST will be standardisable, with a median Einstein radius of 0.9 arcseconds and a median time-delay of 41 days. By breaking the mass-sheet degeneracy the full LSST GLSNe Ia sample will be able to detect systematics in H0 at the 0.5% level.

  5. Strong gravitational lensing by a Konoplya-Zhidenko rotating non-Kerr compact object

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shangyun; Chen, Songbai; Jing, Jiliang, E-mail: shangyun_wang@163.com, E-mail: csb3752@hunnu.edu.cn, E-mail: jljing@hunnu.edu.cn [Institute of Physics and Department of Physics, Hunan Normal University, Changsha, Hunan 410081 (China)

    2016-11-01

    Konoplya and Zhidenko have proposed recently a rotating non-Kerr black hole metric beyond General Relativity and make an estimate for the possible deviations from the Kerr solution with the data of GW 150914. We here study the strong gravitational lensing in such a rotating non-Kerr spacetime with an extra deformation parameter. We find that the condition of existence of horizons is not inconsistent with that of the marginally circular photon orbit. Moreover, the deflection angle of the light ray near the weakly naked singularity covered by the marginally circular orbit diverges logarithmically in the strong-field limit. In the case of the completely naked singularity, the deflection angle near the singularity tends to a certain finite value, whose sign depends on the rotation parameter and the deformation parameter. These properties of strong gravitational lensing are different from those in the Johannsen-Psaltis rotating non-Kerr spacetime and in the Janis-Newman-Winicour spacetime. Modeling the supermassive central object of the Milk Way Galaxy as a Konoplya-Zhidenko rotating non-Kerr compact object, we estimated the numerical values of observables for the strong gravitational lensing including the time delay between two relativistic images.

  6. Strong deflection lensing by charged black holes in scalar-tensor gravity

    Energy Technology Data Exchange (ETDEWEB)

    Eiroa, Ernesto F.; Sendra, Carlos M. [Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Universidad de Buenos Aires, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina)

    2014-11-15

    We examine a class of charged black holes in scalar-tensor gravity as gravitational lenses. We find the deflection angle in the strong deflection limit, from which we obtain the positions and the magnifications of the relativistic images. We compare our results with those corresponding to the Reissner-Norstroem spacetime and we analyze the observational aspects in the case of the Galactic supermassive black hole. (orig.)

  7. Null Geodesics and Strong Field Gravitational Lensing in a String Cloud Background

    International Nuclear Information System (INIS)

    Iftikhar, Sehrish; Sharif, M.

    2015-01-01

    This paper is devoted to studying two interesting issues of a black hole with string cloud background. Firstly, we investigate null geodesics and find unstable orbital motion of particles. Secondly, we calculate deflection angle in strong field limit. We then find positions, magnifications, and observables of relativistic images for supermassive black hole at the galactic center. We conclude that string parameter highly affects the lensing process and results turn out to be quite different from the Schwarzschild black hole

  8. OBSERVED SCALING RELATIONS FOR STRONG LENSING CLUSTERS: CONSEQUENCES FOR COSMOLOGY AND CLUSTER ASSEMBLY

    International Nuclear Information System (INIS)

    Comerford, Julia M.; Moustakas, Leonidas A.; Natarajan, Priyamvada

    2010-01-01

    Scaling relations of observed galaxy cluster properties are useful tools for constraining cosmological parameters as well as cluster formation histories. One of the key cosmological parameters, σ 8 , is constrained using observed clusters of galaxies, although current estimates of σ 8 from the scaling relations of dynamically relaxed galaxy clusters are limited by the large scatter in the observed cluster mass-temperature (M-T) relation. With a sample of eight strong lensing clusters at 0.3 8 , but combining the cluster concentration-mass relation with the M-T relation enables the inclusion of unrelaxed clusters as well. Thus, the resultant gains in the accuracy of σ 8 measurements from clusters are twofold: the errors on σ 8 are reduced and the cluster sample size is increased. Therefore, the statistics on σ 8 determination from clusters are greatly improved by the inclusion of unrelaxed clusters. Exploring cluster scaling relations further, we find that the correlation between brightest cluster galaxy (BCG) luminosity and cluster mass offers insight into the assembly histories of clusters. We find preliminary evidence for a steeper BCG luminosity-cluster mass relation for strong lensing clusters than the general cluster population, hinting that strong lensing clusters may have had more active merging histories.

  9. Testing the Speed of Gravitational Waves over Cosmological Distances with Strong Gravitational Lensing.

    Science.gov (United States)

    Collett, Thomas E; Bacon, David

    2017-03-03

    Probing the relative speeds of gravitational waves and light acts as an important test of general relativity and alternative theories of gravity. Measuring the arrival time of gravitational waves (GWs) and electromagnetic (EM) counterparts can be used to measure the relative speeds, but only if the intrinsic time lag between emission of the photons and gravitational waves is well understood. Here we suggest a method that does not make such an assumption, using future strongly lensed GW events and EM counterparts; Biesiada et al. [J. Cosmol. Astropart. Phys.10 (2014) 080JCAPBP1475-751610.1088/1475-7516/2014/10/080] forecast that 50-100 strongly lensed GW events will be observed each year with the Einstein Telescope. A single strongly lensed GW event would produce robust constraints on c_{GW}/c_{γ} at the 10^{-7} level, if a high-energy EM counterpart is observed within the field of view of an observing γ-ray burst monitor.

  10. STRONG GRAVITATIONAL LENSING BY THE SUPER-MASSIVE cD GALAXY IN ABELL 3827

    International Nuclear Information System (INIS)

    Carrasco, E. R.; Gomez, P. L.; Lee, H.; Diaz, R.; Bergmann, M.; Turner, J. E. H.; Miller, B. W.; West, M. J.; Verdugo, T.

    2010-01-01

    We have discovered strong gravitational lensing features in the core of the nearby cluster Abell 3827 by analyzing Gemini South GMOS images. The most prominent strong lensing feature is a highly magnified, ring-shaped configuration of four images around the central cD galaxy. GMOS spectroscopic analysis puts this source at z ∼ 0.2. Located ∼20'' away from the central galaxy is a secondary tangential arc feature which has been identified as a background galaxy with z ∼ 0.4. We have modeled the gravitational potential of the cluster core, taking into account the mass from the cluster, the brightest cluster galaxy (BCG), and other galaxies. We derive a total mass of (2.7 ± 0.4) x 10 13 M sun within 37 h -1 kpc. This mass is an order of magnitude larger than that derived from X-ray observations. The total mass derived from lensing data suggests that the BCG in this cluster is perhaps the most massive galaxy in the nearby universe.

  11. ALGORITHMS AND PROGRAMS FOR STRONG GRAVITATIONAL LENSING IN KERR SPACE-TIME INCLUDING POLARIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Bin; Maddumage, Prasad [Research Computing Center, Department of Scientific Computing, Florida State University, Tallahassee, FL 32306 (United States); Kantowski, Ronald; Dai, Xinyu; Baron, Eddie, E-mail: bchen3@fsu.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)

    2015-05-15

    Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), then a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravity field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing the strong lensing effects of Kerr black holes, including the effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using the “mpi4py” package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity related computations using interpreted languages such as MATLAB and Python.

  12. ALGORITHMS AND PROGRAMS FOR STRONG GRAVITATIONAL LENSING IN KERR SPACE-TIME INCLUDING POLARIZATION

    International Nuclear Information System (INIS)

    Chen, Bin; Maddumage, Prasad; Kantowski, Ronald; Dai, Xinyu; Baron, Eddie

    2015-01-01

    Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), then a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravity field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing the strong lensing effects of Kerr black holes, including the effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using the “mpi4py” package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity related computations using interpreted languages such as MATLAB and Python

  13. Herschel extreme lensing line observations: Dynamics of two strongly lensed star-forming galaxies near redshift z = 2

    International Nuclear Information System (INIS)

    Rhoads, James E.; Malhotra, Sangeeta; Allam, Sahar; Carilli, Chris; Combes, Françoise; Finkelstein, Keely; Finkelstein, Steven; Frye, Brenda; Gerin, Maryvonne; Guillard, Pierre; Nesvadba, Nicole; Rigby, Jane; Spaans, Marco; Strauss, Michael A.

    2014-01-01

    We report on two regularly rotating galaxies at redshift z ≈ 2, using high-resolution spectra of the bright [C II] 158 μm emission line from the HIFI instrument on the Herschel Space Observatory. Both SDSS090122.37+181432.3 ( S 0901 ) and SDSSJ120602.09+514229.5 ( t he Clone ) are strongly lensed and show the double-horned line profile that is typical of rotating gas disks. Using a parametric disk model to fit the emission line profiles, we find that S0901 has a rotation speed of vsin (i) ≈ 120 ± 7 km s –1 and a gas velocity dispersion of σ g < 23 km s –1 (1σ). The best-fitting model for the Clone is a rotationally supported disk having vsin (i) ≈ 79 ± 11 km s –1 and σ g ≲ 4 km s –1 (1σ). However, the Clone is also consistent with a family of dispersion-dominated models having σ g = 92 ± 20 km s –1 . Our results showcase the potential of the [C II] line as a kinematic probe of high-redshift galaxy dynamics: [C II] is bright, accessible to heterodyne receivers with exquisite velocity resolution, and traces dense star-forming interstellar gas. Future [C II] line observations with ALMA would offer the further advantage of spatial resolution, allowing a clearer separation between rotation and velocity dispersion.

  14. Dark matter distributions in early-type galaxies from strong gravitational lensing

    International Nuclear Information System (INIS)

    Eichner, Thomas Martin

    2013-01-01

    Dark matter constitutes a large fraction of the mass of early-type galaxies. However, the exact amount and spatial distribution of the dark matter, especially in the galaxies' center is still unclear. Furthermore, galaxies in dense environments such as the centers of galaxy clusters shrink in size, since parts of their outer dark matter halo is stripped away. The aim of this thesis is to measure the dark matter content in the centers and outskirts of elliptical galaxies by analyzing the strong gravitational lensing effect they produce. Gravitational lensing is well-suited for investigating dark matter, since it is sensitive to all forms of matter, regardless of its dynamical or evolutionary state. We present gravitational lensing studies of the exceptional strong lensing systems SDSS J1538+5817 and SDSS J1430+4105, identified by the Sloan Lens ACS survey. The lenses are elliptical galaxies at z l =0.143 and z l =0.285, respectively. For SDSS J1538+5817 we show that both multiple imaged sources are located at the same redshift z s =0.531. Its multiple images span a range from 1 to 4 kpc in the plane of the lens. For SDSS J1430+4105, the source at redshift z s =0.575 is imaged into a broad Einstein ring, covering radii from 4 kpc to 10 kpc in the plane of the lens. In both cases, the lensed images can be accurately and consistently reproduced with different modeling approaches. We get projected total masses of 8.11 +0.27 -0.59 x 10 10 M s un within the Einstein radius of 2.5 kpc for SDSS J1538+5817 and 5.37±0.06 x 10 11 M s un within 6.5 kpc for SDSS J1430+4105. The luminous and dark matter were traced separately, resulting in dark matter fractions within the Einstein radius of 0.1 +0.2 -0.1 and 0.40 +0.14 -0.10 for SDSS J1538+5817 and SDSS J1430+4105, respectively. We assume a de Vaucouleurs profile to trace the light distribution of both galaxies. From the stellar mass associated with this light, we can explicitly derive a stellar mass-to-light ratio of (M de

  15. Strong lensing of a regular black hole with an electrodynamics source

    Science.gov (United States)

    Manna, Tuhina; Rahaman, Farook; Molla, Sabiruddin; Bhadra, Jhumpa; Shah, Hasrat Hussain

    2018-05-01

    In this paper we have investigated the gravitational lensing phenomenon in the strong field regime for a regular, charged, static black holes with non-linear electrodynamics source. We have obtained the angle of deflection and compared it to a Schwarzschild black hole and Reissner Nordström black hole with similar properties. We have also done a graphical study of the relativistic image positions and magnifications. We hope that this method may be useful in the detection of non-luminous bodies like this current black hole.

  16. Reducing biases on H0 measurements using strong lensing and galaxy dynamics: results from the EAGLE simulation

    Science.gov (United States)

    Tagore, Amitpal S.; Barnes, David J.; Jackson, Neal; Kay, Scott T.; Schaller, Matthieu; Schaye, Joop; Theuns, Tom

    2018-03-01

    Cosmological parameter constraints from observations of time-delay lenses are becoming increasingly precise. However, there may be significant bias and scatter in these measurements due to, among other things, the so-called mass-sheet degeneracy. To estimate these uncertainties, we analyse strong lenses from the largest EAGLE hydrodynamical simulation. We apply a mass-sheet transformation to the radial density profiles of lenses, and by selecting lenses near isothermality, we find that the bias on H0 can be reduced to 5 per cent with an intrinsic scatter of 10 per cent, confirming previous results performed on a different simulation data set. We further investigate whether combining lensing observables with kinematic constraints helps to minimize this bias. We do not detect any significant dependence of the bias on lens model parameters or observational properties of the galaxy, but depending on the source-lens configuration, a bias may still exist. Cross lenses provide an accurate estimate of the Hubble constant, while fold (double) lenses tend to be biased low (high). With kinematic constraints, double lenses show bias and intrinsic scatter of 6 per cent and 10 per cent, respectively, while quad lenses show bias and intrinsic scatter of 0.5 per cent and 10 per cent, respectively. For lenses with a reduced χ2 > 1, a power-law dependence of the χ2 on the lens environment (number of nearby galaxies) is seen. Lastly, we model, in greater detail, the cases of two double lenses that are significantly biased. We are able to remove the bias, suggesting that the remaining biases could also be reduced by carefully taking into account additional sources of systematic uncertainty.

  17. Probing the Small-scale Structure in Strongly Lensed Systems via Transdimensional Inference

    Science.gov (United States)

    Daylan, Tansu; Cyr-Racine, Francis-Yan; Diaz Rivero, Ana; Dvorkin, Cora; Finkbeiner, Douglas P.

    2018-02-01

    Strong lensing is a sensitive probe of the small-scale density fluctuations in the Universe. We implement a pipeline to model strongly lensed systems using probabilistic cataloging, which is a transdimensional, hierarchical, and Bayesian framework to sample from a metamodel (union of models with different dimensionality) consistent with observed photon count maps. Probabilistic cataloging allows one to robustly characterize modeling covariances within and across lens models with different numbers of subhalos. Unlike traditional cataloging of subhalos, it does not require model subhalos to improve the goodness of fit above the detection threshold. Instead, it allows the exploitation of all information contained in the photon count maps—for instance, when constraining the subhalo mass function. We further show that, by not including these small subhalos in the lens model, fixed-dimensional inference methods can significantly mismodel the data. Using a simulated Hubble Space Telescope data set, we show that the subhalo mass function can be probed even when many subhalos in the sample catalogs are individually below the detection threshold and would be absent in a traditional catalog. The implemented software, Probabilistic Cataloger (PCAT) is made publicly available at https://github.com/tdaylan/pcat.

  18. Probing Motion of Fast Radio Burst Sources by Timing Strongly Lensed Repeaters

    Science.gov (United States)

    Dai, Liang; Lu, Wenbin

    2017-09-01

    Given the possible repetitive nature of fast radio bursts (FRBs), their cosmological origin, and their high occurrence, detection of strongly lensed sources due to intervening galaxy lenses is possible with forthcoming radio surveys. We show that if multiple images of a repeating source are resolved with VLBI, using a method independent of lens modeling, accurate timing could reveal non-uniform motion, either physical or apparent, of the emission spot. This can probe the physical nature of FRBs and their surrounding environments, constraining scenarios including orbital motion around a stellar companion if FRBs require a compact star in a special system, and jet-medium interactions for which the location of the emission spot may randomly vary. The high timing precision possible for FRBs (˜ms) compared with the typical time delays between images in galaxy lensing (≳10 days) enables the measurement of tiny fractional changes in the delays (˜ {10}-9) and hence the detection of time-delay variations induced by relative motions between the source, the lens, and the Earth. We show that uniform cosmic peculiar velocities only cause the delay time to drift linearly, and that the effect from the Earth’s orbital motion can be accurately subtracted, thus enabling a search for non-trivial source motion. For a timing accuracy of ˜1 ms and a repetition rate (of detected bursts) of ˜0.05 per day of a single FRB source, non-uniform displacement ≳0.1-1 au of the emission spot perpendicular to the line of sight is detectable if repetitions are seen over a period of hundreds of days.

  19. Cosmological Studies with Galaxy Clusters, Active Galactic Nuclei, and Strongly Lensed Quasars

    Science.gov (United States)

    Rumbaugh, Nicholas Andrew

    transitional `green valley' on a color-magnitude diagram. Spectral analysis of the AGN hosts showed that the average host galaxy had either on-going or recent star formation, and was younger than the average galaxy, across all LSS in our sample. We further subdivided our sample in two based on the average evolutionary state of the LSS. The AGN in the more evolved structures had lower X-ray luminosities and longer times since last starburst. These results provide some evidence for merger-based AGN triggering, although other mechanisms, and possibly more than one, could be responsible. In the third study, we probed LambdaCDM cosmology from a different angle. An important part of the model is the cosmological parameters that define our universe. As such, probes that can more accurately and precisely measure these parameters, such as H0 and the dark energy equation of state, w, can allow us to more closely inspect the model. Strongly-lensed quasars provide one such probe, and we sought to perform the first step in using them for cosmological inference, which is to measure the time delays between strongly lensed images. We performed radio monitoring campaigns on six strongly lensed quasars using the Very Large Array. Lightcurves were extracted for each lensed image and analyzed for intrinsic variability. Two lensed quasars showed strong time variations, but the variations were linear in time, preventing precise time delay measurements due to a degeneracy with the magnifications. These results suggest most of the systems should be targeted for followup monitoring, and we estimate that time delays can be measured for the most variable systems with precision of 0.5 to 3.5 days with two more seasons of monitoring. In a joint fit with previously studied systems, these measurements could tighten constraints on H 0 by up to ~1.4.

  20. CENTRAL DARK MATTER TRENDS IN EARLY-TYPE GALAXIES FROM STRONG LENSING, DYNAMICS, AND STELLAR POPULATIONS

    International Nuclear Information System (INIS)

    Tortora, C.; Jetzer, P.; Napolitano, N. R.; Romanowsky, A. J.

    2010-01-01

    We analyze the correlations between central dark matter (DM) content of early-type galaxies and their sizes and ages, using a sample of intermediate-redshift (z ∼ 0.2) gravitational lenses from the SLACS survey, and by comparing them to a larger sample of z ∼ 0 galaxies. We decompose the deprojected galaxy masses into DM and stellar components using combinations of strong lensing, stellar dynamics, and stellar populations modeling. For a given stellar mass, we find that for galaxies with larger sizes, the DM fraction increases and the mean DM density decreases, consistently with the cuspy halos expected in cosmological formation scenarios. The DM fraction also decreases with stellar age, which can be partially explained by the inverse correlation between size and age. The residual trend may point to systematic dependencies on formation epoch of halo contraction or stellar initial mass functions. These results are in agreement with recent findings based on local galaxies by Napolitano et al. and suggest negligible evidence of galaxy evolution over the last ∼2.5 Gyr other than passive stellar aging.

  1. Strong lensing probability in TeVeS (tensor–vector–scalar) theory

    International Nuclear Information System (INIS)

    Chen Daming

    2008-01-01

    We recalculate the strong lensing probability as a function of the image separation in TeVeS (tensor–vector–scalar) cosmology, which is a relativistic version of MOND (MOdified Newtonian Dynamics). The lens is modeled by the Hernquist profile. We assume an open cosmology with Ω b = 0.04 and Ω Λ = 0.5 and three different kinds of interpolating functions. Two different galaxy stellar mass functions (GSMF) are adopted: PHJ (Panter, Heavens and Jimenez 2004 Mon. Not. R. Astron. Soc. 355 764) determined from SDSS data release 1 and Fontana (Fontana et al 2006 Astron. Astrophys. 459 745) from GOODS-MUSIC catalog. We compare our results with both the predicted probabilities for lenses from singular isothermal sphere galaxy halos in LCDM (Lambda cold dark matter) with a Schechter-fit velocity function, and the observational results for the well defined combined sample of the Cosmic Lens All-Sky Survey (CLASS) and Jodrell Bank/Very Large Array Astrometric Survey (JVAS). It turns out that the interpolating function μ(x) = x/(1+x) combined with Fontana GSMF matches the results from CLASS/JVAS quite well

  2. Strong lensing probability in TeVeS (tensor-vector-scalar) theory

    Science.gov (United States)

    Chen, Da-Ming

    2008-01-01

    We recalculate the strong lensing probability as a function of the image separation in TeVeS (tensor-vector-scalar) cosmology, which is a relativistic version of MOND (MOdified Newtonian Dynamics). The lens is modeled by the Hernquist profile. We assume an open cosmology with Ωb = 0.04 and ΩΛ = 0.5 and three different kinds of interpolating functions. Two different galaxy stellar mass functions (GSMF) are adopted: PHJ (Panter, Heavens and Jimenez 2004 Mon. Not. R. Astron. Soc. 355 764) determined from SDSS data release 1 and Fontana (Fontana et al 2006 Astron. Astrophys. 459 745) from GOODS-MUSIC catalog. We compare our results with both the predicted probabilities for lenses from singular isothermal sphere galaxy halos in LCDM (Lambda cold dark matter) with a Schechter-fit velocity function, and the observational results for the well defined combined sample of the Cosmic Lens All-Sky Survey (CLASS) and Jodrell Bank/Very Large Array Astrometric Survey (JVAS). It turns out that the interpolating function μ(x) = x/(1+x) combined with Fontana GSMF matches the results from CLASS/JVAS quite well.

  3. Mass density slope of elliptical galaxies from strong lensing and resolved stellar kinematics

    Science.gov (United States)

    Lyskova, N.; Churazov, E.; Naab, T.

    2018-04-01

    We discuss constraints on the mass density distribution (parametrized as ρ ∝ r-γ) in early-type galaxies provided by strong lensing and stellar kinematics data. The constraints come from mass measurements at two `pinch' radii. One `pinch' radius r1 = 2.2REinst is defined such that the Einstein (i.e. aperture) mass can be converted into the spherical mass almost independently of the mass-model. Another `pinch' radius r2 = Ropt is chosen so that the dynamical mass, derived from the line-of-sight velocity dispersion, is least sensitive to the anisotropy of stellar orbits. We verified the performance of this approach on a sample of simulated elliptical galaxies and on a sample of 15 SLACS lens galaxies at 0.01 ≤ z ≤ 0.35, which have already been analysed in Barnabè et al. by the self-consistent joint lensing and kinematic code. For massive simulated galaxies, the density slope γ is recovered with an accuracy of ˜13 per cent, unless r1 and r2 happen to be close to each other. For SLACS galaxies, we found good overall agreement with the results of Barnabè et al. with a sample-averaged slope γ = 2.1 ± 0.05. Although the two-pinch-radii approach has larger statistical uncertainties, it is much simpler and uses only few arithmetic operations with directly observable quantities.

  4. Interpreting the Strongly Lensed Supernova iPTF16geu: Time Delay Predictions, Microlensing, and Lensing Rates

    Energy Technology Data Exchange (ETDEWEB)

    More, Anupreeta; Oguri, Masamune; More, Surhud [Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), University of Tokyo, Chiba 277-8583 (Japan); Suyu, Sherry H. [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Lee, Chien-Hsiu, E-mail: anupreeta.more@ipmu.jp [Subaru Telescope, National Astronomical Observatory of Japan, 650 North Aohoku Place, Hilo, HI 96720 (United States)

    2017-02-01

    We present predictions for time delays between multiple images of the gravitationally lensed supernova, iPTF16geu, which was recently discovered from the intermediate Palomar Transient Factory (iPTF). As the supernova is of Type Ia where the intrinsic luminosity is usually well known, accurately measured time delays of the multiple images could provide tight constraints on the Hubble constant. According to our lens mass models constrained by the Hubble Space Telescope F814W image, we expect the maximum relative time delay to be less than a day, which is consistent with the maximum of 100 hr reported by Goobar et al. but places a stringent upper limit. Furthermore, the fluxes of most of the supernova images depart from expected values suggesting that they are affected by microlensing. The microlensing timescales are small enough that they may pose significant problems to measure the time delays reliably. Our lensing rate calculation indicates that the occurrence of a lensed SN in iPTF is likely. However, the observed total magnification of iPTF16geu is larger than expected, given its redshift. This may be a further indication of ongoing microlensing in this system.

  5. EVIDENCE OF VERY LOW METALLICITY AND HIGH IONIZATION STATE IN A STRONGLY LENSED, STAR-FORMING DWARF GALAXY AT z = 3.417

    International Nuclear Information System (INIS)

    Amorín, R.; Grazian, A.; Castellano, M.; Pentericci, L.; Fontana, A.; Sommariva, V.; Merlin, E.; Van der Wel, A.; Maseda, M.

    2014-01-01

    We investigate the gas-phase metallicity and Lyman continuum (LyC) escape fraction of a strongly gravitationally lensed, extreme emission-line galaxy at z = 3.417, J1000+0221S, recently discovered by the CANDELS team. We derive ionization- and metallicity-sensitive emission-line ratios from H+K band Large Binocular Telescope (LBT)/LUCI medium resolution spectroscopy. J1000+0221S shows high ionization conditions, as evidenced by its enhanced [O III]/[O II] and [O III]/Hβ ratios. Strong-line methods based on the available line ratios suggest that J1000+0221S is an extremely metal-poor galaxy, with a metallicity of 12+log (O/H) < 7.44 (Z < 0.05 Z ☉ ), placing it among the most metal-poor star-forming galaxies at z ≳ 3 discovered so far. In combination with its low stellar mass (2 × 10 8  M ☉ ) and high star formation rate (5 M ☉  yr –1 ), the metallicity of J1000+0221S is consistent with the extrapolation of the mass-metallicity relation traced by Lyman-break galaxies at z ≳ 3 to low masses, but it is 0.55 dex lower than predicted by the fundamental metallicity relation at z ≲ 2.5. These observations suggest a rapidly growing galaxy, possibly fed by massive accretion of pristine gas. Additionally, deep LBT/LBC photometry in the UGR bands are used to derive a limit to the LyC escape fraction, thus allowing us to explore for the first time the regime of sub-L* galaxies at z > 3. We find a 1σ upper limit to the escape fraction of 23%, which adds a new observational constraint to recent theoretical models predicting that sub-L* galaxies at high-z have high escape fractions and thus are the responsible for the reionization of the universe

  6. A COMPREHENSIVE VIEW OF A STRONGLY LENSED PLANCK-ASSOCIATED SUBMILLIMETER GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Fu Hai; Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Jullo, E. [Observatoire d' Astrophysique de Marseille-Provence, 38 rue Frederic Joliot-Curie, F-13388 Marseille (France); Bussmann, R. S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ivison, R. J. [UK Astronomy Technology Centre, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom); Perez-Fournon, I. [Instituto de Astrofisica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Djorgovski, S. G.; Scoville, N.; Yan, L.; Riechers, D. A.; Bradford, M. [Department of Astronomy, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Aguirre, J. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Auld, R. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA (United Kingdom); Baes, M. [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Baker, A. J. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Rd., Piscataway, NJ 08854 (United States); Cava, A. [Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Dannerbauer, H. [Institut fuer Astronomie, Universitaet Wien, Tuerkenschanzstrasse 17, A-1160 Wien (Austria); Dariush, A. [Physics Department, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); De Zotti, G., E-mail: haif@uci.edu [INAF-Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); and others

    2012-07-10

    We present high-resolution maps of stars, dust, and molecular gas in a strongly lensed submillimeter galaxy (SMG) at z = 3.259. HATLAS J114637.9-001132 is selected from the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) as a strong lens candidate mainly based on its unusually high 500 {mu}m flux density ({approx}300 mJy). It is the only high-redshift Planck detection in the 130 deg{sup 2} H-ATLAS Phase-I area. Keck Adaptive Optics images reveal a quadruply imaged galaxy in the K band while the Submillimeter Array and the Jansky Very Large Array show doubly imaged 880 {mu}m and CO(1{yields}0) sources, indicating differentiated distributions of the various components in the galaxy. In the source plane, the stars reside in three major kpc-scale clumps extended over {approx}1.6 kpc, the dust in a compact ({approx}1 kpc) region {approx}3 kpc north of the stars, and the cold molecular gas in an extended ({approx}7 kpc) disk {approx}5 kpc northeast of the stars. The emissions from the stars, dust, and gas are magnified by {approx}17, {approx}8, and {approx}7 times, respectively, by four lensing galaxies at z {approx} 1. Intrinsically, the lensed galaxy is a warm (T{sub dust} {approx} 40-65 K), hyper-luminous (L{sub IR} {approx} 1.7 Multiplication-Sign 10{sup 13} L{sub Sun }; star formation rate (SFR) {approx}2000 M{sub Sun} yr{sup -1}), gas-rich (M{sub gas}/M{sub baryon} {approx} 70%), young (M{sub stellar}/SFR {approx} 20 Myr), and short-lived (M{sub gas}/SFR {approx} 40 Myr) starburst. With physical properties similar to unlensed z > 2 SMGs, HATLAS J114637.9-001132 offers a detailed view of a typical SMG through a powerful cosmic microscope.

  7. DISCOVERY OF A STRONG LENSING GALAXY EMBEDDED IN A CLUSTER AT z = 1.62

    International Nuclear Information System (INIS)

    Wong, Kenneth C.; Suyu, Sherry H.; Tran, Kim-Vy H.; Papovich, Casey J.; Momcheva, Ivelina G.; Brammer, Gabriel B.; Koekemoer, Anton M.; Brodwin, Mark; Gonzalez, Anthony H.; Kacprzak, Glenn G.; Rudnick, Gregory H.; Halkola, Aleksi

    2014-01-01

    We identify a strong lensing galaxy in the cluster IRC 0218 (also known as XMM-LSS J02182–05102) that is spectroscopically confirmed to be at z = 1.62, making it the highest-redshift strong lens galaxy known. The lens is one of the two brightest cluster galaxies and lenses a background source galaxy into an arc and a counterimage. With Hubble Space Telescope (HST) grism and Keck/LRIS spectroscopy, we measure the source redshift to be z S = 2.26. Using HST imaging in ACS/F475W, ACS/F814W, WFC3/F125W, and WFC3/F160W, we model the lens mass distribution with an elliptical power-law profile and account for the effects of the cluster halo and nearby galaxies. The Einstein radius is θ E =0.38 −0.01 +0.02 arcsec (3.2 −0.1 +0.2 kpc) and the total enclosed mass is M tot (<θ E )=1.8 −0.1 +0.2 ×10 11 M ⊙ . We estimate that the cluster environment contributes ∼10% of this total mass. Assuming a Chabrier initial mass function (IMF), the dark matter fraction within θ E is f DM Chab =0.3 −0.3 +0.1 , while a Salpeter IMF is marginally inconsistent with the enclosed mass (f DM Salp =−0.3 −0.5 +0.2 ). The total magnification of the source is μ tot =2.1 −0.3 +0.4 . The source has at least one bright compact region offset from the source center. Emission from Lyα and [O III] are likely to probe different regions in the source

  8. Strong gravitational lensing and the stellar IMF of early-type galaxies

    Science.gov (United States)

    Leier, Dominik; Ferreras, Ignacio; Saha, Prasenjit; Charlot, Stéphane; Bruzual, Gustavo; La Barbera, Francesco

    2016-07-01

    Systematic variations of the initial mass function (IMF) in early-type galaxies, and their connection with possible drivers such as velocity dispersion or metallicity, have been much debated in recent years. Strong lensing over galaxy scales combined with photometric and spectroscopic data provides a powerful method to constrain the stellar mass-to-light ratio and hence the functional form of the IMF. We combine photometric and spectroscopic constraints from the latest set of population synthesis models of Charlot & Bruzual, including a varying IMF, with a non-parametric analysis of the lens masses of 18 ETGs from the SLACS survey, with velocity dispersions in the range 200-300 km s-1. We find that very bottom-heavy IMFs are excluded. However, the upper limit to the bimodal IMF slope (μ ≲ 2.2, accounting for a dark matter fraction of 20-30 per cent, where μ = 1.3 corresponds to a Kroupa-like IMF) is compatible at the 1σ level with constraints imposed by gravity-sensitive line strengths. A two-segment power-law parametrization of the IMF (Salpeter-like for high masses) is more constrained (Γ ≲ 1.5, where Γ is the power index at low masses) but requires a dark matter contribution of ≳25 per cent to reconcile the results with a Salpeter IMF. For a standard Milky Way-like IMF to be applicable, a significant dark matter contribution is required within 1Re. Our results reveal a large range of allowed IMF slopes, which, when interpreted as intrinsic scatter in the IMF properties of ETGs, could explain the recent results of Smith et al., who find Milky Way-like IMF normalizations in a few massive lensing ETGs.

  9. THE SLOAN BRIGHT ARCS SURVEY: TEN STRONG GRAVITATIONAL LENSING CLUSTERS AND EVIDENCE OF OVERCONCENTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Wiesner, Matthew P. [Department of Physics, Northern Illinois University, DeKalb, IL 60115 (United States); Lin, Huan; Allam, Sahar S.; Annis, James; Buckley-Geer, Elizabeth J.; Diehl, H. Thomas; Kubik, Donna; Kubo, Jeffrey M.; Tucker, Douglas [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)

    2012-12-10

    We describe 10 strong lensing galaxy clusters of redshift 0.26 {<=} z {<=} 0.56 that were found in the Sloan Digital Sky Survey. We present measurements of richness (N{sub 200}), mass (M{sub 200}), and velocity dispersion for the clusters. We find that in order to use the mass-richness relation from Johnston et al., which was established at mean redshift of 0.25, it is necessary to scale measured richness values up by 1.47. Using this scaling, we find richness values for these clusters to be in the range of 22 {<=} N{sub 200} {<=} 317 and mass values to be in the range of 1 Multiplication-Sign 10{sup 14} h {sup -1} M{sub Sun} {<=} M{sub 200} {<=} 30 Multiplication-Sign 10{sup 14} h {sup -1} M{sub Sun }. We also present measurements of Einstein radius, mass, and velocity dispersion for the lensing systems. The Einstein radii ({theta}{sub E}) are all relatively small, with 5.''4 {<=} {theta}{sub E} {<=} 13''. Finally, we consider if there is evidence that our clusters are more concentrated than {Lambda}CDM would predict. We find that six of our clusters do not show evidence of overconcentration, while four of our clusters do. We note a correlation between overconcentration and mass, as the four clusters showing evidence of overconcentration are all lower-mass clusters. For the four lowest mass clusters the average value of the concentration parameter c{sub 200} is 11.6, while for the six higher-mass clusters the average value of c{sub 200} is 4.4. {Lambda}CDM would place c{sub 200} between 3.4 and 5.7.

  10. SDSS-IV MaNGA: the spectroscopic discovery of strongly lensed galaxies

    Science.gov (United States)

    Talbot, Michael S.; Brownstein, Joel R.; Bolton, Adam S.; Bundy, Kevin; Andrews, Brett H.; Cherinka, Brian; Collett, Thomas E.; More, Anupreeta; More, Surhud; Sonnenfeld, Alessandro; Vegetti, Simona; Wake, David A.; Weijmans, Anne-Marie; Westfall, Kyle B.

    2018-06-01

    We present a catalogue of 38 spectroscopically detected strong galaxy-galaxy gravitational lens candidates identified in the Sloan Digital Sky Survey IV (SDSS-IV). We were able to simulate narrow-band images for eight of them demonstrating evidence of multiple images. Two of our systems are compound lens candidates, each with two background source-planes. One of these compound systems shows clear lensing features in the narrow-band image. Our sample is based on 2812 galaxies observed by the Mapping Nearby Galaxies at APO (MaNGA) integral field unit (IFU). This Spectroscopic Identification of Lensing Objects (SILO) survey extends the methodology of the Sloan Lens ACS Survey (SLACS) and BOSS Emission-Line Survey (BELLS) to lower redshift and multiple IFU spectra. We searched ˜1.5 million spectra, of which 3065 contained multiple high signal-to-noise ratio background emission-lines or a resolved [O II] doublet, that are included in this catalogue. Upon manual inspection, we discovered regions with multiple spectra containing background emission-lines at the same redshift, providing evidence of a common source-plane geometry which was not possible in previous SLACS and BELLS discovery programs. We estimate more than half of our candidates have an Einstein radius ≳ 1.7 arcsec, which is significantly greater than seen in SLACS and BELLS. These larger Einstein radii produce more extended images of the background galaxy increasing the probability that a background emission-line will enter one of the IFU spectroscopic fibres, making detection more likely.

  11. Chandra and ALMA observations of the nuclear activity in two strongly lensed star-forming galaxies

    Science.gov (United States)

    Massardi, M.; Enia, A. F. M.; Negrello, M.; Mancuso, C.; Lapi, A.; Vignali, C.; Gilli, R.; Burkutean, S.; Danese, L.; Zotti, G. De

    2018-02-01

    Aim. According to coevolutionary scenarios, nuclear activity and star formation play relevant roles in the early stages of galaxy formation. We aim at identifying them in high-redshift galaxies by exploiting high-resolution and high-sensitivity X-ray and millimeter-wavelength data to confirm the presence or absence of star formation and nuclear activity and describe their relative roles in shaping the spectral energy distributions and in contributing to the energy budgets of the galaxies. Methods: We present the data, model, and analysis in the X-ray and millimeter (mm) bands for two strongly lensed galaxies, SDP.9 (HATLAS J090740.0-004200) and SDP.11 (HATLAS J091043.1-000322), which we selected in the Herschel-ATLAS catalogs for their excess emission in the mid-IR regime at redshift ≳1.5. This emission suggests nuclear activity in the early stages of galaxy formation. We observed both of them with Chandra ACIS-S in the X-ray regime and analyzed the high-resolution mm data that are available in the ALMA Science Archive for SDP.9. By combining the information available in mm, optical, and X-ray bands, we reconstructed the source morphology. Results: Both targets were detected in the X-ray, which strongly indicates highly obscured nuclear activity. ALMA observations for SDP.9 for the continuum and CO(6-5) spectral line with high resolution (0.02 arcsec corresponding to 65 pc at the distance of the galaxy) allowed us to estimate the lensed galaxy redshift to a better accuracy than pre-ALMA estimates (1.5753 ± 0.0003) and to model the emission of the optical, millimetric, and X-ray band for this galaxy. We demonstrate that the X-ray emission is generated in the nuclear environment, which strongly supports that this object has nuclear activity. On the basis of the X-ray data, we attempt an estimate of the black hole properties in these galaxies. Conclusions: By taking advantage of the lensing magnification, we identify weak nuclear activity associated with high

  12. DISCOVERY OF A STRONG LENSING GALAXY EMBEDDED IN A CLUSTER AT z = 1.62

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Kenneth C.; Suyu, Sherry H. [Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), P.O. Box 23-141, Taipei 10617, Taiwan (China); Tran, Kim-Vy H.; Papovich, Casey J. [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Momcheva, Ivelina G. [Astronomy Department, Yale University, New Haven, CT 06511 (United States); Brammer, Gabriel B.; Koekemoer, Anton M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Brodwin, Mark [Department of Physics and Astronomy, University of Missouri, 5110 Rockhill Road, Kansas City, MO 64110 (United States); Gonzalez, Anthony H. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Kacprzak, Glenn G. [Swinburne University of Technology, Victoria 3122 (Australia); Rudnick, Gregory H. [Department of Physics and Astronomy, The University of Kansas, Malott Room 1082, 1251 Wescoe Hall Drive, Lawrence, KS 66045 (United States); Halkola, Aleksi

    2014-07-10

    We identify a strong lensing galaxy in the cluster IRC 0218 (also known as XMM-LSS J02182–05102) that is spectroscopically confirmed to be at z = 1.62, making it the highest-redshift strong lens galaxy known. The lens is one of the two brightest cluster galaxies and lenses a background source galaxy into an arc and a counterimage. With Hubble Space Telescope (HST) grism and Keck/LRIS spectroscopy, we measure the source redshift to be z {sub S} = 2.26. Using HST imaging in ACS/F475W, ACS/F814W, WFC3/F125W, and WFC3/F160W, we model the lens mass distribution with an elliptical power-law profile and account for the effects of the cluster halo and nearby galaxies. The Einstein radius is θ{sub E}=0.38{sub −0.01}{sup +0.02} arcsec (3.2{sub −0.1}{sup +0.2} kpc) and the total enclosed mass is M {sub tot}(<θ{sub E})=1.8{sub −0.1}{sup +0.2}×10{sup 11} M{sub ⊙}. We estimate that the cluster environment contributes ∼10% of this total mass. Assuming a Chabrier initial mass function (IMF), the dark matter fraction within θ{sub E} is f{sub DM}{sup Chab}=0.3{sub −0.3}{sup +0.1}, while a Salpeter IMF is marginally inconsistent with the enclosed mass (f{sub DM}{sup Salp}=−0.3{sub −0.5}{sup +0.2}). The total magnification of the source is μ{sub tot}=2.1{sub −0.3}{sup +0.4}. The source has at least one bright compact region offset from the source center. Emission from Lyα and [O III] are likely to probe different regions in the source.

  13. OBSERVATION AND CONFIRMATION OF SIX STRONG-LENSING SYSTEMS IN THE DARK ENERGY SURVEY SCIENCE VERIFICATION DATA

    International Nuclear Information System (INIS)

    Nord, B.; Buckley-Geer, E.; Lin, H.; Diehl, H. T.; Kuropatkin, N.; Allam, S.; Finley, D. A.; Flaugher, B.; Gaitsch, H.; Merritt, K. W.; Helsby, J.; Amara, A.; Collett, T.; Caminha, G. B.; De Bom, C.; Da Pereira, M. Elidaiana S.; Desai, S.; Dúmet-Montoya, H.; Furlanetto, C.; Gill, M.

    2016-01-01

    We report the observation and confirmation of the first group- and cluster-scale strong gravitational lensing systems found in Dark Energy Survey data. Through visual inspection of data from the Science Verification season, we identified 53 candidate systems. We then obtained spectroscopic follow-up of 21 candidates using the Gemini Multi-object Spectrograph at the Gemini South telescope and the Inamori-Magellan Areal Camera and Spectrograph at the Magellan/Baade telescope. With this follow-up, we confirmed six candidates as gravitational lenses: three of the systems are newly discovered, and the remaining three were previously known. Of the 21 observed candidates, the remaining 15 either were not detected in spectroscopic observations, were observed and did not exhibit continuum emission (or spectral features), or were ruled out as lensing systems. The confirmed sample consists of one group-scale and five galaxy-cluster-scale lenses. The lensed sources range in redshift z ∼ 0.80–3.2 and in i -band surface brightness i SB ∼ 23–25 mag arcsec −2 (2″ aperture). For each of the six systems, we estimate the Einstein radius θ E and the enclosed mass M enc , which have ranges θ E ∼ 5″–9″ and M enc ∼ 8 × 10 12 to 6 × 10 13 M ⊙ , respectively.

  14. OBSERVATION AND CONFIRMATION OF SIX STRONG-LENSING SYSTEMS IN THE DARK ENERGY SURVEY SCIENCE VERIFICATION DATA

    Energy Technology Data Exchange (ETDEWEB)

    Nord, B.; Buckley-Geer, E.; Lin, H.; Diehl, H. T.; Kuropatkin, N.; Allam, S.; Finley, D. A.; Flaugher, B.; Gaitsch, H.; Merritt, K. W. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Helsby, J. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Amara, A. [Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 16, CH-8093 Zurich (Switzerland); Collett, T. [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Caminha, G. B.; De Bom, C.; Da Pereira, M. Elidaiana S. [ICRA, Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, CEP 22290-180, Rio de Janeiro, RJ (Brazil); Desai, S. [Excellence Cluster Universe, Boltzmannstrasse 2, D-85748 Garching (Germany); Dúmet-Montoya, H. [Universidade Federal do Rio de Janeiro—Campus Macaé, Rua Aloísio Gomes da Silva, 50—Granja dos Cavaleiros, Cep: 27930-560, Macaé, RJ (Brazil); Furlanetto, C. [University of Nottingham, School of Physics and Astronomy, Nottingham NG7 2RD (United Kingdom); Gill, M., E-mail: nord@fnal.gov [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Collaboration: DES Collaboration; and others

    2016-08-10

    We report the observation and confirmation of the first group- and cluster-scale strong gravitational lensing systems found in Dark Energy Survey data. Through visual inspection of data from the Science Verification season, we identified 53 candidate systems. We then obtained spectroscopic follow-up of 21 candidates using the Gemini Multi-object Spectrograph at the Gemini South telescope and the Inamori-Magellan Areal Camera and Spectrograph at the Magellan/Baade telescope. With this follow-up, we confirmed six candidates as gravitational lenses: three of the systems are newly discovered, and the remaining three were previously known. Of the 21 observed candidates, the remaining 15 either were not detected in spectroscopic observations, were observed and did not exhibit continuum emission (or spectral features), or were ruled out as lensing systems. The confirmed sample consists of one group-scale and five galaxy-cluster-scale lenses. The lensed sources range in redshift z ∼ 0.80–3.2 and in i -band surface brightness i {sub SB} ∼ 23–25 mag arcsec{sup −2} (2″ aperture). For each of the six systems, we estimate the Einstein radius θ {sub E} and the enclosed mass M {sub enc}, which have ranges θ {sub E} ∼ 5″–9″ and M {sub enc} ∼ 8 × 10{sup 12} to 6 × 10{sup 13} M {sub ⊙}, respectively.

  15. Core or Cusps: The Central Dark Matter Profile of a Strong Lensing Cluster with a Bright Central Image at Redshift 1

    Energy Technology Data Exchange (ETDEWEB)

    Collett, Thomas E.; Buckley-Geer, Elizabeth; Lin, Huan; Bacon, David; Nichol, Robert C.; Nord, Brian; Morice-Atkinson, Xan; Amara, Adam; Birrer, Simon; Kuropatkin, Nikolay; More, Anupreeta; Papovich, Casey; Romer, Kathy K.; Tessore, Nicolas; Abbott, Tim M. C.; Allam, Sahar; Annis, James; Benoit-Lévy, Aurlien; Brooks, David; Burke, David L.; Carrasco Kind, Matias; Castander, Francisco Javier J.; D’Andrea, Chris B.; da Costa, Luiz N.; Desai, Shantanu; Diehl, H. Thomas; Doel, Peter; Eifler, Tim F.; Flaugher, Brenna; Frieman, Josh; Gerdes, David W.; Goldstein, Daniel A.; Gruen, Daniel; Gschwend, Julia; Gutierrez, Gaston; James, David J.; Kuehn, Kyler; Kuhlmann, Steve; Lahav, Ofer; Li, Ting S.; Lima, Marcos; Maia, Marcio A. G.; March, Marisa; Marshall, Jennifer L.; Martini, Paul; Melchior, Peter; Miquel, Ramon; Plazas, Andrs A.; Rykoff, Eli S.; Sanchez, Eusebio; Scarpine, Vic; Schindler, Rafe; Schubnell, Michael; Sevilla-Noarbe, Ignacio; Smith, Mathew; Sobreira, Flavia; Suchyta, Eric; Swanson, Molly E. C.; Tarle, Gregory; Tucker, Douglas L.; Walker, Alistair R.

    2017-07-10

    We report on SPT-CLJ2011-5228, a giant system of arcs created by a cluster at $z=1.06$. The arc system is notable for the presence of a bright central image. The source is a Lyman Break galaxy at $z_s=2.39$ and the mass enclosed within the 14 arc second radius Einstein ring is $10^{14.2}$ solar masses. We perform a full light profile reconstruction of the lensed images to precisely infer the parameters of the mass distribution. The brightness of the central image demands that the central total density profile of the lens be shallow. By fitting the dark matter as a generalized Navarro-Frenk-White profile---with a free parameter for the inner density slope---we find that the break radius is $270^{+48}_{-76}$ kpc, and that the inner density falls with radius to the power $-0.38\\pm0.04$ at 68 percent confidence. Such a shallow profile is in strong tension with our understanding of relaxed cold dark matter halos; dark matter only simulations predict the inner density should fall as $r^{-1}$. The tension can be alleviated if this cluster is in fact a merger; a two halo model can also reconstruct the data, with both clumps (density going as $r^{-0.8}$ and $r^{-1.0}$) much more consistent with predictions from dark matter only simulations. At the resolution of our Dark Energy Survey imaging, we are unable to choose between these two models, but we make predictions for forthcoming Hubble Space Telescope imaging that will decisively distinguish between them.

  16. A MAGNIFIED GLANCE INTO THE DARK SECTOR: PROBING COSMOLOGICAL MODELS WITH STRONG LENSING IN A1689

    International Nuclear Information System (INIS)

    Magaña, Juan; Motta, V.; Cárdenas, Victor H.; Verdugo, T.; Jullo, Eric

    2015-01-01

    In this paper we constrain four alternative models to the late cosmic acceleration in the universe: Chevallier–Polarski–Linder (CPL), interacting dark energy (IDE), Ricci holographic dark energy (HDE), and modified polytropic Cardassian (MPC). Strong lensing (SL) images of background galaxies produced by the galaxy cluster Abell 1689 are used to test these models. To perform this analysis we modify the LENSTOOL lens modeling code. The value added by this probe is compared with other complementary probes: Type Ia supernovae (SN Ia), baryon acoustic oscillations (BAO), and cosmic microwave background (CMB). We found that the CPL constraints obtained for the SL data are consistent with those estimated using the other probes. The IDE constraints are consistent with the complementary bounds only if large errors in the SL measurements are considered. The Ricci HDE and MPC constraints are weak, but they are similar to the BAO, SN Ia, and CMB estimations. We also compute the figure of merit as a tool to quantify the goodness of fit of the data. Our results suggest that the SL method provides statistically significant constraints on the CPL parameters but is weak for those of the other models. Finally, we show that the use of the SL measurements in galaxy clusters is a promising and powerful technique to constrain cosmological models. The advantage of this method is that cosmological parameters are estimated by modeling the SL features for each underlying cosmology. These estimations could be further improved by SL constraints coming from other galaxy clusters

  17. DES meets Gaia: discovery of strongly lensed quasars from a multiplet search

    Energy Technology Data Exchange (ETDEWEB)

    Agnello, A.; et al.

    2017-11-10

    We report the discovery, spectroscopic confirmation and first lens models of the first two, strongly lensed quasars from a combined search in WISE and Gaia over the DES footprint. The four-image lensWGD2038-4008 (r.a.=20:38:02.65, dec.=-40:08:14.64) has source- and lens-redshifts $z_{s}=0.777 \\pm 0.001$ and $z_l = 0.230 \\pm 0.002$ respectively. Its deflector has effective radius $R_{\\rm eff} \\approx 3.4^{\\prime\\prime}$, stellar mass $\\log(M_{\\star}/M_{\\odot}) = 11.64^{+0.20}_{-0.43}$, and shows extended isophotal shape variation. Simple lens models yield Einstein radii $R_{\\rm E}=(1.30\\pm0.04)^{\\prime\\prime},$ axis ratio $q=0.75\\pm0.1$ (compatible with that of the starlight) and considerable shear-ellipticity degeneracies. The two-image lensWGD2021-4115 (r.a.=20:21:39.45, dec.=--41:15:57.11) has $z_{s}=1.390\\pm0.001$ and $z_l = 0.335 \\pm 0.002$, and Einstein radius $R_{\\rm E} = (1.1\\pm0.1)^{\\prime\\prime},$ but higher-resolution imaging is needed to accurately separate the deflector and faint quasar image. We also show high-rank candidate doubles selected this way, some of which have been independently identified with different techniques, and discuss a DES+WISE quasar multiplet selection.

  18. The SPT+Herschel+ALMA+Spitzer Legacy Survey: The stellar content of high redshift strongly lensed systems

    Science.gov (United States)

    Vieira, Joaquin; Ashby, Matt; Carlstrom, John; Chapman, Scott; DeBreuck, Carlos; Fassnacht, Chris; Gonzalez, Anthony; Phadke, Kedar; Marrone, Dan; Malkan, Matt; Reuter, Cassie; Rotermund, Kaja; Spilker, Justin; Weiss, Axel

    2018-05-01

    The South Pole Telescope (SPT) has systematically identified 90 high-redshift strongly gravitationally lensed submillimeter galaxies (SMGs) in a 2500 square-degree cosmological survey of the millimeter (mm) sky. These sources are selected by their extreme mm flux, which is largely independent of redshift and lensing configuration. We are undertaking a comprehensive and systematic followup campaign to use these "cosmic magnifying glasses" to study the infrared background in unprecedented detail, inform the condition of the interstellar medium in starburst galaxies at high redshift, and place limits on dark matter substructure. Here we ask for 115.4 hours of deep Spitzer/IRAC imaging to complete our survey of 90 systems to a uniform depth of 30min integrations at 3.6um and 60min at 4.5um. In our sample of 90 systems, 16 have already been fully observed, 30 have been partially observed, and 44 have not been observed at all. Our immediate goals are to: 1) constrain the specific star formation rates of the background high-redshift submillimeter galaxies by combining these Spitzer observations with our APEX, Herschel, and ALMA data, 2) robustly determine the stellar masses and mass-to-light ratios of all the foreground lensing galaxies in the sample by combining these observations with our VLT and Gemini data, the Dark Energy Survey, and ALMA; and 3) provide complete, deep, and uniform NIR coverage of our entire sample of lensed systems to characterize the environments of high redshift SMGs, maximize the discovery potential for additional spectacular and rare sources, and prepare for JWST. This program will provide the cornerstone data set for two PhD theses: Kedar Phadke at Illinois will lead the analysis of stellar masses for the background SMGs, and Kaja Rotermund at Dalhousie will lead the analysis of stellar masses for the foreground lenses.

  19. Exploring a Potential Bias in Dark Matter Investigations Using Strongly Lensed Quasars

    NARCIS (Netherlands)

    Hsueh, Jen-Wei; Fassnacht, Christopher; Vegetti, Simona; Springola, Cristiana; Oldham, Lindsay; Despali, Giulia; Auger, Matthew; Xu, Dandan; Metcalf, Benton; McKean, John; Koopmans, Leon; Lagattuta, David

    2018-01-01

    Simulations based on ΛCDM cosmology predict thousands of substructures under galactic scale have not been detected in the local universe. One hypothesis proposes that most of these substructures are dark for various astrophysical reasons. Gravitational lensing provides a powerful alternative way to

  20. SPITZER IMAGING OF STRONGLY LENSED HERSCHEL-SELECTED DUSTY STAR-FORMING GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Brian; Cooray, Asantha; Calanog, J. A.; Nayyeri, H.; Timmons, N.; Casey, C. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Baes, M. [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Chapman, S. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, B3H 4R2 (Canada); Dannerbauer, H. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); Da Cunha, E. [Center for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn VIC 3122 (Australia); De Zotti, G. [INAF-Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, I-35122 Padova (Italy); Dunne, L.; Michałowski, M. J.; Oteo, I. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Fu, Hai [Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242 (United States); Gonzalez-Nuevo, J. [Departamento de Fisica, Universidad de Oviedo C/ Calvo Sotelo, s/n, E-33007 Oviedo (Spain); Magdis, G. [Department of Astrophysics, Denys Wilkinson Building, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Riechers, D. A. [Department of Astronomy, Cornell University, 220 Space Sciences Building, Ithaca, NY 14853 (United States); Scott, D. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); and others

    2015-11-20

    We present the rest-frame optical spectral energy distribution (SED) and stellar masses of six Herschel-selected gravitationally lensed dusty, star-forming galaxies (DSFGs) at 1 < z < 3. These galaxies were first identified with Herschel/SPIRE imaging data from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) and the Herschel Multi-tiered Extragalactic Survey (HerMES). The targets were observed with Spitzer/IRAC at 3.6 and 4.5 μm. Due to the spatial resolution of the IRAC observations at the level of 2″, the lensing features of a background DSFG in the near-infrared are blended with the flux from the foreground lensing galaxy in the IRAC imaging data. We make use of higher resolution Hubble/WFC3 or Keck/NIRC2 Adaptive Optics imaging data to fit light profiles of the foreground lensing galaxy (or galaxies) as a way to model the foreground components, in order to successfully disentangle the foreground lens and background source flux densities in the IRAC images. The flux density measurements at 3.6 and 4.5 μm, once combined with Hubble/WFC3 and Keck/NIRC2 data, provide important constraints on the rest-frame optical SED of the Herschel-selected lensed DSFGs. We model the combined UV- to millimeter-wavelength SEDs to establish the stellar mass, dust mass, star formation rate, visual extinction, and other parameters for each of these Herschel-selected DSFGs. These systems have inferred stellar masses in the range 8 × 10{sup 10}–4 × 10{sup 11} M{sub ⊙} and star formation rates of around 100 M{sub ⊙} yr{sup −1}. This puts these lensed submillimeter systems well above the SFR-M* relation observed for normal star-forming galaxies at similar redshifts. The high values of SFR inferred for these systems are consistent with a major merger-driven scenario for star formation.

  1. Discovery of three strongly lensed quasars in the Sloan Digital Sky Survey

    Science.gov (United States)

    Williams, P. R.; Agnello, A.; Treu, T.; Abramson, L. E.; Anguita, T.; Apostolovski, Y.; Chen, G. C.-F.; Fassnacht, C. D.; Hsueh, J. W.; Lemaux, B. C.; Motta, V.; Oldham, L.; Rojas, K.; Rusu, C. E.; Shajib, A. J.; Wang, X.

    2018-06-01

    We present the discovery of three quasar lenses in the Sloan Digital Sky Survey, selected using two novel photometry-based selection techniques. The J0941+0518 system, with two point sources separated by 5.46 arcsec on either side of a galaxy, has source and lens redshifts 1.54 and 0.343. Images of J2257+2349 show two point sources separated by 1.67 arcsec on either side of an E/S0 galaxy. The extracted spectra show two images of the same quasar at zs = 2.10. SDSS J1640+1045 has two quasar spectra at zs = 1.70 and fits to the SDSS and Pan-STARRS images confirm the presence of a galaxy between the two point sources. We observed 56 photometrically selected lens candidates in this follow-up campaign, confirming three new lenses, re-discovering one known lens, and ruling out 36 candidates, with 16 still inconclusive. This initial campaign demonstrates the power of purely photometric selection techniques in finding lensed quasars.

  2. Rest-Frame Optical Spectra of Three Strongly Lensed Galaxies at z ~ 2

    Science.gov (United States)

    Hainline, Kevin N.; Shapley, Alice E.; Kornei, Katherine A.; Pettini, Max; Buckley-Geer, Elizabeth; Allam, Sahar S.; Tucker, Douglas L.

    2009-08-01

    We present Keck II NIRSPEC rest-frame optical spectra for three recently discovered lensed galaxies: the Cosmic Horseshoe (z = 2.38), the Clone (z = 2.00), and SDSS J090122.37+181432.3 (z = 2.26). The boost in signal-to-noise ratio (S/N) from gravitational lensing provides an unusually detailed view of the physical conditions in these objects. A full complement of high S/N rest-frame optical emission lines is measured, spanning from rest frame 3600 to 6800 Å, including robust detections of fainter lines such as Hγ, [S II]λ6717,6732, and in one instance [Ne III]λ3869. SDSS J090122.37+181432.3 shows evidence for active galactic nucleus activity, and therefore we focus our analysis on star-forming regions in the Cosmic Horseshoe and the Clone. For these two objects, we estimate a wide range of physical properties. Current lensing models for the Cosmic Horseshoe and the Clone allow us to correct the measured Hα luminosity and calculated star formation rate. Metallicities have been estimated with a variety of indicators, which span a range of values of 12+ log(O/H) = 8.3-8.8, between ~0.4 and ~1.5 of the solar oxygen abundance. Dynamical masses were computed from the Hα velocity dispersions and measured half-light radii of the reconstructed sources. A comparison of the Balmer lines enabled measurement of dust reddening coefficients. Variations in the line ratios between the different lensed images are also observed, indicating that the spectra are probing different regions of the lensed galaxies. In all respects, the lensed objects appear fairly typical of ultraviolet-selected star-forming galaxies at z ~ 2. The Clone occupies a position on the emission-line diagnostic diagram of [O III]/Hβ versus [N II]/Hα that is offset from the locations of z ~ 0 galaxies. Our new NIRSPEC measurements may provide quantitative insights into why high-redshift objects display such properties. From the [S II] line ratio, high electron densities (~1000 cm-3) are inferred compared

  3. A strong-lensing elliptical galaxy in the MaNGA survey

    Science.gov (United States)

    Smith, Russell J.

    2017-01-01

    I report discovery of a new galaxy-scale gravitational lens system, identified using public data from the Mapping Galaxies at Apache Point Observatory (MaNGA) survey, as part of a systematic search for lensed background line emitters. The lens is SDSS J170124.01+372258.0, a giant elliptical galaxy with velocity dispersion σ = 256 km s-1, at a redshift of zl = 0.122. After modelling and subtracting the target galaxy light, the integral-field data cube reveals [O II], [O III] and Hβ emission lines corresponding to a source at zs = 0.791, forming an identifiable ring around the galaxy centre. If the ring is formed by a single lensed source, then the Einstein radius is REin ≈ 2.3 arcsec, projecting to ˜5 kpc at the distance of the lens. The total projected lensing mass is MEin = (3.6 ± 0.6) × 1011 M⊙, and the total J-band mass-to-light ratio is 3.0 ± 0.7 solar units. Plausible estimates of the likely dark matter content could reconcile this with a Milky Way-like initial mass function (IMF), for which M/L ≈ 1.5 is expected, but heavier IMFs are by no means excluded with the present data. An alternative interpretation of the system, with a more complex source plane, is also discussed. The discovery of this system bodes well for future lens searches based on MaNGA and other integral-field spectroscopic surveys.

  4. Strong bimodality in the host halo mass of central galaxies from galaxy-galaxy lensing

    Science.gov (United States)

    Mandelbaum, Rachel; Wang, Wenting; Zu, Ying; White, Simon; Henriques, Bruno; More, Surhud

    2016-04-01

    We use galaxy-galaxy lensing to study the dark matter haloes surrounding a sample of locally brightest galaxies (LBGs) selected from the Sloan Digital Sky Survey. We measure mean halo mass as a function of the stellar mass and colour of the central galaxy. Mock catalogues constructed from semi-analytic galaxy formation simulations demonstrate that most LBGs are the central objects of their haloes, greatly reducing interpretation uncertainties due to satellite contributions to the lensing signal. Over the full stellar mass range, 10.3 10.7. Tests using the mock catalogues and on the data themselves clarify the effects of LBG selection and show that it cannot artificially induce a systematic dependence of halo mass on LBG colour. The bimodality in halo mass at fixed stellar mass is reproduced by the astrophysical model underlying our mock catalogue, but the sign of the effect is inconsistent with recent, nearly parameter-free age-matching models. The sign and magnitude of the effect can, however, be reproduced by halo occupation distribution models with a simple (few-parameter) prescription for type dependence.

  5. Models of the strongly lensed quasar DES J0408-5354

    Science.gov (United States)

    Agnello, A.; Lin, H.; Buckley-Geer, L.; Treu, T.; Bonvin, V.; Courbin, F.; Lemon, C.; Morishita, T.; Amara, A.; Auger, M. W.; Birrer, S.; Chan, J.; Collett, T.; More, A.; Fassnacht, C. D.; Frieman, J.; Marshall, P. J.; McMahon, R. G.; Meylan, G.; Suyu, S. H.; Castander, F.; Finley, D.; Howell, A.; Kochanek, C.; Makler, M.; Martini, P.; Morgan, N.; Nord, B.; Ostrovski, F.; Schechter, P.; Tucker, D.; Wechsler, R.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Dietrich, J. P.; Eifler, T. F.; Flaugher, B.; Fosalba, P.; García-Bellido, J.; Gaztanaga, E.; Gill, M. S.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Li, T. S.; Lima, M.; Maia, M. A. G.; March, M.; Marshall, J. L.; Melchior, P.; Menanteau, F.; Miquel, R.; Ogando, R. L. C.; Plazas, A. A.; Romer, A. K.; Sanchez, E.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, M.; Smith, R. C.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.

    2017-12-01

    We present detailed modelling of the recently discovered, quadruply lensed quasar J0408-5354, with the aim of interpreting its remarkable configuration: besides three quasar images (A,B,D) around the main deflector (G1), a fourth image (C) is significantly reddened and dimmed by a perturber (G2) which is not detected in the Dark Energy Survey imaging data. From lens models incorporating (dust-corrected) flux ratios, we find a perturber Einstein radius 0.04 arcsec ≲ RE, G2 ≲ 0.2 arcsec and enclosed mass Mp(RE, G2) ≲ 1.0 × 1010 M⊙. The main deflector has stellar mass log _{10}(M_{\\star }/M_{⊙})=11.49^{+0.46}_{-0.32}, a projected mass Mp(RE, G1) ≈ 6 × 1011 M⊙ within its Einstein radius RE, G1 = (1.85 ± 0.15) arcsec and predicted velocity dispersion 267-280 km s-1. Follow-up images from a companion monitoring campaign show additional components, including a candidate second source at a redshift between the quasar and G1. Models with free perturbers, and dust-corrected and delay-corrected flux ratios, are also explored. The predicted time-delays (ΔtAB = (135.0 ± 12.6) d, ΔtBD = (21.0 ± 3.5) d) roughly agree with those measured, but better imaging is required for proper modelling and comparison. We also discuss some lessons learnt from J0408-5354 on lensed quasar finding strategies, due to its chromaticity and morphology.

  6. A STRONGLY LENSED MASSIVE ULTRACOMPACT QUIESCENT GALAXY AT z ∼ 2.4 IN THE COSMOS/UltraVISTA FIELD

    International Nuclear Information System (INIS)

    Muzzin, Adam; Labbé, Ivo; Franx, Marijn; Holt, J.; Szomoru, Daniel; Van de Sande, Jesse; Van Dokkum, Pieter; Brammer, Gabriel; Marchesini, Danilo; Stefanon, Mauro; Buitrago, F.; Dunlop, James; Caputi, K. I.; Fynbo, J. P. U.; Milvang-Jensen, Bo; Le Févre, Olivier; McCracken, Henry J.

    2012-01-01

    We report the discovery of a massive ultracompact quiescent galaxy that has been strongly lensed into multiple images by a foreground galaxy at z 0.960. This system was serendipitously discovered as a set of extremely K s -bright high-redshift galaxies with red J – K s colors using new data from the UltraVISTA YJHK s near-infrared survey. The system was also previously identified as an optically faint lens/source system using the COSMOS Advanced Camera for Surveys (ACS) imaging by Faure et al. Photometric redshifts for the three brightest images of the source galaxy determined from 27-band photometry place the source at z = 2.4 ± 0.1. We provide an updated lens model for the system that is a good fit to the positions and morphologies of the galaxies in the ACS image. The lens model implies that the magnification of the three brightest images is a factor of 4-5. We use the lens model, combined with the K s -band image, to constrain the size and Sérsic profile of the galaxy. The best-fit model is an ultracompact galaxy (R e = 0.64 +0.08 –0.18 kpc, lensing-corrected), with a Sérsic profile that is intermediate between a disk and a bulge profile (n 2.2 +2.3 – 0 .9 ), albeit with considerable uncertainties on the Sérsic profile. We present aperture photometry for the source galaxy images that have been corrected for flux contamination from the central lens. The best-fit stellar population model is a massive galaxy (log(M star /M ☉ ) = 10.8 +0.1 –0.1 , lensing-corrected) with an age of 1.0 +1.0 –0.4 Gyr, moderate dust extinction (A v = 0.8 +0.5 –0.6 ), and a low specific star formation rate (log(SSFR) –1 ). This is typical of massive ''red-and-dead'' galaxies at this redshift and confirms that this source is the first bona fide strongly lensed massive ultracompact quiescent galaxy to be discovered. We conclude with a discussion of the prospects of finding a larger sample of these galaxies.

  7. SUB-KILOPARSEC IMAGING OF COOL MOLECULAR GAS IN TWO STRONGLY LENSED DUSTY, STAR-FORMING GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Spilker, J. S.; Marrone, D. P. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Aravena, M. [Núcleo de Astronomía, Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército 441, Santiago (Chile); Béthermin, M.; Breuck, C. de [European Southern Observatory, Karl Schwarzschild Straße 2, D-85748 Garching (Germany); Bothwell, M. S. [Cavendish Laboratory, University of Cambridge, JJ Thompson Ave, Cambridge CB3 0HA (United Kingdom); Carlstrom, J. E. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Chapman, S. C.; Rotermund, K. M. [Dalhousie University, Halifax, Nova Scotia (Canada); Collier, J. D.; Galvin, T.; Grieve, K.; O’Brien, A. [University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751 (Australia); Fassnacht, C. D. [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Gonzalez, A. H.; Ma, J. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); González-López, J. [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago (Chile); Hezaveh, Y. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States); Malkan, M., E-mail: jspilker@as.arizona.edu [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States); and others

    2015-10-01

    We present spatially resolved imaging obtained with the Australia Telescope Compact Array (ATCA) of three CO lines in two high-redshift gravitationally lensed dusty star-forming galaxies, discovered by the South Pole Telescope. Strong lensing allows us to probe the structure and dynamics of the molecular gas in these two objects, at z = 2.78 and z = 5.66, with effective source-plane resolution of less than 1 kpc. We model the lensed emission from multiple CO transitions and the dust continuum in a consistent manner, finding that the cold molecular gas as traced by low-J CO always has a larger half-light radius than the 870 μm dust continuum emission. This size difference leads to up to 50% differences in the magnification factor for the cold gas compared to dust. In the z = 2.78 galaxy, these CO observations confirm that the background source is undergoing a major merger, while the velocity field of the other source is more complex. We use the ATCA CO observations and comparable resolution Atacama Large Millimeter/submillimeter Array dust continuum imaging of the same objects to constrain the CO–H{sub 2} conversion factor with three different procedures, finding good agreement between the methods and values consistent with those found for rapidly star-forming systems. We discuss these galaxies in the context of the star formation—gas mass surface density relation, noting that the change in emitting area with observed CO transition must be accounted for when comparing high-redshift galaxies to their lower redshift counterparts.

  8. Reflection from the strong gravity regime in a lensed quasar at redshift z = 0.658.

    Science.gov (United States)

    Reis, R C; Reynolds, M T; Miller, J M; Walton, D J

    2014-03-13

    The co-evolution of a supermassive black hole with its host galaxy through cosmic time is encoded in its spin. At z > 2, supermassive black holes are thought to grow mostly by merger-driven accretion leading to high spin. It is not known, however, whether below z ≈ 1 these black holes continue to grow by coherent accretion or in a chaotic manner, though clear differences are predicted in their spin evolution. An established method of measuring the spin of black holes is through the study of relativistic reflection features from the inner accretion disk. Owing to their greater distances from Earth, there has hitherto been no significant detection of relativistic reflection features in a moderate-redshift quasar. Here we report an analysis of archival X-ray data together with a deep observation of a gravitationally lensed quasar at z = 0.658. The emission originates within three or fewer gravitational radii from the black hole, implying a spin parameter (a measure of how fast the black hole is rotating) of a = 0.87(+0.08)(-0.15) at the 3σ confidence level and a > 0.66 at the 5σ level. The high spin found here is indicative of growth by coherent accretion for this black hole, and suggests that black-hole growth at 0.5 ≤ z ≤ 1 occurs principally by coherent rather than chaotic accretion episodes.

  9. VizieR Online Data Catalog: Strong lensing mass modeling of 4 HFF clusters (Kawamata+, 2016)

    Science.gov (United States)

    Kawamata, R.; Oguri, M.; Ishigaki, M.; Shimasaku, K.; Ouchi, M.

    2018-02-01

    We use the public HFF data (http://www.stsci.edu/hst/campaigns/frontier-fields/) for our analysis. The HFF targets six massive clusters, Abell 2744 (z=0.308), MACS J0416.1-2403 (z=0.397), MACS J0717.5+3745 (z=0.545), MACS J1149.6+2223 (z=0.541), Abell S1063 (z=0.348), and Abell 370 (z=0.375), which have been chosen according to their lensing strength and also their accessibility from major ground-based telescopes. The cluster core and parallel field region of each cluster are observed deeply with the IR channel of Wide Field Camera 3 (WFC3/IR) and the Advanced Camera for Surveys (ACS). As of 2015 October, HST observations for the first four clusters, Abell 2744, MACS J0416.1-2403, MACS J0717.5+3745, and MACS J1149.6+2223, are completed. In this study, we use the Version 1.0 data products of drizzled images with a pixel scale of 0.03"/pixel provided by the Space Telescope Science Institute (STScI). The images for each cluster consist of F435W (B435), F606W (V606), and F814W (i814) images from ACS, and F105W (Y105), F125W (J125), F140W (JH140), and F160W (H160) images from WFC3/IR. (7 data files).

  10. Lyman Alpha Control

    CERN Document Server

    Nielsen, Daniel Stefaniak

    2015-01-01

    This document gives an overview of how to operate the Lyman Alpha Control application written in LabVIEW along with things to watch out for. Overview of the LabVIEW code itself as well as the physical wiring of and connections from/to the NI PCI-6229 DAQ box is also included. The Lyman Alpha Control application is the interface between the ALPHA sequencer and the HighFinesse Wavelength Meter as well as the Lyman Alpha laser setup. The application measures the wavelength of the output light from the Lyman Alpha cavity through the Wavelength Meter. The application can use the Wavelength Meter’s PID capabilities to stabilize the Lyman Alpha laser output as well as switch between up to three frequencies.

  11. Models of the Strongly Lensed Quasar DES J0408-5354

    Energy Technology Data Exchange (ETDEWEB)

    Agnello, A.; et al.

    2017-02-01

    We present gravitational lens models of the multiply imaged quasar DES J0408-5354, recently discovered in the Dark Energy Survey (DES) footprint, with the aim of interpreting its remarkable quad-like configuration. We first model the DES single-epoch $grizY$ images as a superposition of a lens galaxy and four point-like objects, obtaining spectral energy distributions (SEDs) and relative positions for the objects. Three of the point sources (A,B,D) have SEDs compatible with the discovery quasar spectra, while the faintest point-like image (G2/C) shows significant reddening and a `grey' dimming of $\\approx0.8$mag. In order to understand the lens configuration, we fit different models to the relative positions of A,B,D. Models with just a single deflector predict a fourth image at the location of G2/C but considerably brighter and bluer. The addition of a small satellite galaxy ($R_{\\rm E}\\approx0.2$") in the lens plane near the position of G2/C suppresses the flux of the fourth image and can explain both the reddening and grey dimming. All models predict a main deflector with Einstein radius between $1.7"$ and $2.0",$ velocity dispersion $267-280$km/s and enclosed mass $\\approx 6\\times10^{11}M_{\\odot},$ even though higher resolution imaging data are needed to break residual degeneracies in model parameters. The longest time-delay (B-A) is estimated as $\\approx 85$ (resp. $\\approx125$) days by models with (resp. without) a perturber near G2/C. The configuration and predicted time-delays of J0408-5354 make it an excellent target for follow-up aimed at understanding the source quasar host galaxy and substructure in the lens, and measuring cosmological parameters. We also discuss some lessons learnt from J0408-5354 on lensed quasar finding strategies, due to its chromaticity and morphology.

  12. Generalised model-independent characterisation of strong gravitational lenses. II. Transformation matrix between multiple images

    Science.gov (United States)

    Wagner, J.; Tessore, N.

    2018-05-01

    We determine the transformation matrix that maps multiple images with identifiable resolved features onto one another and that is based on a Taylor-expanded lensing potential in the vicinity of a point on the critical curve within our model-independent lens characterisation approach. From the transformation matrix, the same information about the properties of the critical curve at fold and cusp points can be derived as we previously found when using the quadrupole moment of the individual images as observables. In addition, we read off the relative parities between the images, so that the parity of all images is determined when one is known. We compare all retrievable ratios of potential derivatives to the actual values and to those obtained by using the quadrupole moment as observable for two- and three-image configurations generated by a galaxy-cluster scale singular isothermal ellipse. We conclude that using the quadrupole moments as observables, the properties of the critical curve are retrieved to a higher accuracy at the cusp points and to a lower accuracy at the fold points; the ratios of second-order potential derivatives are retrieved to comparable accuracy. We also show that the approach using ratios of convergences and reduced shear components is equivalent to ours in the vicinity of the critical curve, but yields more accurate results and is more robust because it does not require a special coordinate system as the approach using potential derivatives does. The transformation matrix is determined by mapping manually assigned reference points in the multiple images onto one another. If the assignment of the reference points is subject to measurement uncertainties under the influence of noise, we find that the confidence intervals of the lens parameters can be as large as the values themselves when the uncertainties are larger than one pixel. In addition, observed multiple images with resolved features are more extended than unresolved ones, so that

  13. J0454-0309: evidence of a strong lensing fossil group falling into a poor galaxy cluster

    Science.gov (United States)

    Schirmer, M.; Suyu, S.; Schrabback, T.; Hildebrandt, H.; Erben, T.; Halkola, A.

    2010-05-01

    Aims: We have discovered a strong lensing fossil group (J0454) projected near the well-studied cluster MS0451-0305. Using the large amount of available archival data, we compare J0454 to normal groups and clusters. A highly asymmetric image configuration of the strong lens enables us to study the substructure of the system. Methods: We used multicolour Subaru/Suprime-Cam and CFHT/Megaprime imaging, together with Keck spectroscopy to identify member galaxies. A VLT/FORS2 spectrum was taken to determine the redshifts of the brightest elliptical and the lensed arc. Using HST/ACS images, we determined the group's weak lensing signal and modelled the strong lens system. This is the first time that a fossil group is analysed with lensing methods. The X-ray luminosity and temperature were derived from XMM-Newton data. Results: J0454 is located at z = 0.26, with a gap of 2.5 mag between the brightest and second brightest galaxies within half the virial radius. Outside a radius of 1.5 Mpc, we find two filaments extending over 4 Mpc, and within we identify 31 members spectroscopically and 33 via the red sequence with i systems, a sparse cluster and an infalling fossil group, where the latter seeds the brightest cluster galaxy. An alternative to the sparse cluster could be a filament projected along the line of sight mimicking a cluster, with galaxies streaming towards the fossil group. This work is based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii; based on observations made with ESO Telescopes at the La Silla and Paranal Observatories, Chile (ESO DDT

  14. The Herschel-ATLAS: magnifications and physical sizes of 500-μm-selected strongly lensed galaxies

    Science.gov (United States)

    Enia, A.; Negrello, M.; Gurwell, M.; Dye, S.; Rodighiero, G.; Massardi, M.; De Zotti, G.; Franceschini, A.; Cooray, A.; van der Werf, P.; Birkinshaw, M.; Michałowski, M. J.; Oteo, I.

    2018-04-01

    We perform lens modelling and source reconstruction of Sub-millimetre Array (SMA) data for a sample of 12 strongly lensed galaxies selected at 500μm in the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS). A previous analysis of the same data set used a single Sérsic profile to model the light distribution of each background galaxy. Here we model the source brightness distribution with an adaptive pixel scale scheme, extended to work in the Fourier visibility space of interferometry. We also present new SMA observations for seven other candidate lensed galaxies from the H-ATLAS sample. Our derived lens model parameters are in general consistent with previous findings. However, our estimated magnification factors, ranging from 3 to 10, are lower. The discrepancies are observed in particular where the reconstructed source hints at the presence of multiple knots of emission. We define an effective radius of the reconstructed sources based on the area in the source plane where emission is detected above 5σ. We also fit the reconstructed source surface brightness with an elliptical Gaussian model. We derive a median value reff ˜ 1.77 kpc and a median Gaussian full width at half-maximum ˜1.47 kpc. After correction for magnification, our sources have intrinsic star formation rates (SFR) ˜ 900-3500 M⊙ yr-1, resulting in a median SFR surface density ΣSFR ˜ 132 M⊙ yr-1 kpc-2 (or ˜218 M⊙ yr-1 kpc-2 for the Gaussian fit). This is consistent with that observed for other star-forming galaxies at similar redshifts, and is significantly below the Eddington limit for a radiation pressure regulated starburst.

  15. Null Geodesics and Strong Field Gravitational Lensing of Black Hole with Global Monopole

    International Nuclear Information System (INIS)

    Iftikhar, Sehrish; Sharif, M.

    2015-01-01

    We study two interesting features of a black hole with an ordinary as well as phantom global monopole. Firstly, we investigate null geodesics which imply unstable orbital motion of particles for both cases. Secondly, we evaluate deflection angle in strong field regime. We then find Einstein rings, magnifications, and observables of the relativistic images for supermassive black hole at the center of galaxy NGC4486B. We also examine time delays for different galaxies and present our results numerically. It is found that the deflection angle for ordinary/phantom global monopole is greater/smaller than that of Schwarzschild black hole. In strong field limit, the remaining properties of these black holes are quite different from the Schwarzschild black hole

  16. FAST VARIABILITY AND MILLIMETER/IR FLARES IN GRMHD MODELS OF Sgr A* FROM STRONG-FIELD GRAVITATIONAL LENSING

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Chi-kwan; Psaltis, Dimitrios; Özel, Feryal; Marrone, Daniel [Steward Observatory and Department of Astronomy, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Medeiros, Lia [Department of Physics, Broida Hall, University of California, Santa Barbara, Santa Barbara, CA 93106 (United States); Sadowski, Aleksander [MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Narayan, Ramesh, E-mail: chanc@email.arizona.edu [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2015-10-20

    We explore the variability properties of long, high-cadence general relativistic magnetohydrodynamic (GRMHD) simulations across the electromagnetic spectrum using an efficient, GPU-based radiative transfer algorithm. We focus on both standard and normal evolution (SANE) and magnetically arrested disk (MAD) simulations with parameters that successfully reproduce the time-averaged spectral properties of Sgr A* and the size of its image at 1.3 mm. We find that the SANE models produce short-timescale variability with amplitudes and power spectra that closely resemble those inferred observationally. In contrast, MAD models generate only slow variability at lower flux levels. Neither set of models shows any X-ray flares, which most likely indicates that additional physics, such as particle acceleration mechanisms, need to be incorporated into the GRMHD simulations to account for them. The SANE models show strong, short-lived millimeter/infrared (IR) flares, with short (≲1 hr) time lags between the millimeter and IR wavelengths, that arise from the combination of short-lived magnetic flux tubes and strong-field gravitational lensing near the horizon. Such events provide a natural explanation for the observed IR flares with no X-ray counterparts.

  17. LYMAN : a new window on the universe

    International Nuclear Information System (INIS)

    Dopita, M.A.; Tuohy, I.R.; Mathewson, D.S.; Hunstead, R.W.; Waterworth, M.D.

    1988-01-01

    This document is the final Phase A Science Report of the Australian LYMAN Science Working Group, and describes in detail the scientific objectives, technical feasibility, and engineering implementation of the LYMAN mission as developed in the Australian studies. LYMAN represents the next generation, high-orbit, UV space observatory, and is designed to operate over the wavelength range λ 100 - 1900 Angstrom. The prime spectral range is λ 900 - 1250 Angstrom, which will be covered at a resolution of λ/Δ λ = 30000, and the sensitivity of the instrumentation will be orders of magnitude better than previous missions. In this region we find the Lyman series of molecular and atomic hydrogen, as well as a whole host of atomic and ionic lines of great diagnostic power. LYMAN will be able to accomplish uniquely valuable astrophysics as a result, and will be applied to the study of all types of astronomical targets in the fields of cosmology, galactic research, the interstellar medium, stars in all stages of their evolution, and to particular solar system objects. The LYMAN Mission was the subject of a $1M study contract awarded by the Australian Space Office, a section of DITAC, to Auspace Pty. Ltd. The Phase A study was conduced in parallel with the ESA Phase A Study, and with a strong scientific and technical liaison between the two groups. LYMAN is now likely to be launched as a joint ESA/NASA project, but the future Australian role in the mission, as determined by current policy, would be minimal. Australia would therefore be effectively locked out of the very exciting front-line science described in this document, and the valuable university - industry liaison that has been developed over the last eight years will be lost

  18. Bright Strongly Lensed Galaxies at Redshift z ~ 6-7 behind the Clusters Abell 1703 and CL0024+16

    Science.gov (United States)

    Zheng, W.; Bradley, L. D.; Bouwens, R. J.; Ford, H. C.; Illingworth, G. D.; Benítez, N.; Broadhurst, T.; Frye, B.; Infante, L.; Jee, M. J.; Motta, V.; Shu, X. W.; Zitrin, A.

    2009-06-01

    We report on the discovery of three bright, strongly lensed objects behind Abell 1703 and CL0024+16 from a dropout search over 25 arcmin2 of deep NICMOS data, with deep ACS optical coverage. They are undetected in the deep ACS images below 8500 Å and have clear detections in the J and H bands. Fits to the ACS, NICMOS, and IRAC data yield robust photometric redshifts in the range z ~ 6-7 and largely rule out the possibility that they are low-redshift interlopers. All three objects are extended, and resolved into a pair of bright knots. The bright i-band dropout in Abell 1703 has an H-band AB magnitude of 23.9, which makes it one of the brightest known galaxy candidates at z > 5.5. Our model fits suggest a young, massive galaxy only ~60 million years old with a mass of ~1010 M sun. The dropout galaxy candidates behind CL0024+16 are separated by 2farcs5 (~2 kpc in the source plane), and have H-band AB magnitudes of 25.0 and 25.6. Lensing models of CL0024+16 suggest that the objects have comparable intrinsic magnitudes of AB ~27.3, approximately one magnitude fainter than L* at z ~ 6.5. Their similar redshifts, spectral energy distribution, and luminosities, coupled with their very close proximity on the sky, suggest that they are spatially associated, and plausibly are physically bound. Combining this sample with two previously reported, similarly magnified galaxy candidates at z ~ 6-8, we find that complex systems with dual nuclei may be a common feature of high-redshift galaxies. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities of Research in Astronomy, Inc., under NASA contract NAS5-26555, and at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle

  19. A new strong-lensing galaxy at z=0.066: Another elliptical galaxy with a lightweight IMF

    Science.gov (United States)

    Collier, William P.; Smith, Russell J.; Lucey, John R.

    2018-05-01

    We report the discovery of a new low-redshift galaxy-scale gravitational lens, identified from a systematic search of publicly available MUSE observations. The lens galaxy, 2MASXJ04035024-0239275, is a giant elliptical at z = 0.06604 with a velocity dispersion of σ = 314 km s-1. The lensed source has a redshift of 0.19165 and forms a pair of bright images on either side of the lens centre. The Einstein radius is 1.5 arcsec, projecting to 1.8 kpc, which is just one quarter of the galaxy effective radius. After correcting for an estimated 19 per cent dark matter contribution, we find that the stellar mass-to-light ratio from lensing is consistent with that expected for a Milky Way initial mass function (IMF). Combining the new system with three previously-studied low-redshift lenses of similar σ, the derived mean mass excess factor (relative to a Kroupa IMF) is ⟨α⟩ = 1.09±0.08. With all four systems, the intrinsic scatter in α for massive elliptical galaxies can be limited to <0.32, at 90 per cent confidence.

  20. Spatially Resolved Patchy Ly α Emission within the Central Kiloparsec of a Strongly Lensed Quasar Host Galaxy at z = 2.8

    Energy Technology Data Exchange (ETDEWEB)

    Bayliss, Matthew B.; Bordoloi, Rongmon [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Sharon, Keren; Runnoe, Jessie; Johnson, Traci; Paterno-Mahler, Rachel [Department of Astronomy, University of Michigan, 1085 S. University Avenue, Ann Arbor, MI 48109 (United States); Acharyya, Ayan; Bian, Fuyan; Kewley, Lisa [RSAA, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Gladders, Michael D. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Rigby, Jane R. [Astrophysics Science Division, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Dahle, Hakon [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway); Florian, Michael, E-mail: mbayliss@mit.edu [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

    2017-08-20

    We report the detection of extended Ly α emission from the host galaxy of SDSS J2222+2745, a strongly lensed quasar at z = 2.8. Spectroscopic follow-up clearly reveals extended Ly α in emission between two images of the central active galactic nucleus (AGN). We reconstruct the lensed quasar host galaxy in the source plane by applying a strong lens model to HST imaging and resolve spatial scales as small as ∼200 pc. In the source plane, we recover the host galaxy morphology to within a few hundred parsecs of the central AGN and map the extended Ly α emission to its physical origin on one side of the host galaxy at radii ∼0.5–2 kpc from the central AGN. There are clear morphological differences between the Ly α and rest-frame ultraviolet stellar continuum emission from the quasar host galaxy. Furthermore, the relative velocity profiles of quasar Ly α , host galaxy Ly α , and metal lines in outflowing gas reveal differences in the absorbing material affecting the AGN and host galaxy. These data indicate the presence of patchy local intervening gas in front of the central quasar and its host galaxy. This interpretation is consistent with the central luminous quasar being obscured across a substantial fraction of its surrounding solid angle, resulting in strong anisotropy in the exposure of the host galaxy to ionizing radiation from the AGN. This work demonstrates the power of strong-lensing-assisted studies to probe spatial scales that are currently inaccessible by other means.

  1. Spatially Resolved Patchy Ly α Emission within the Central Kiloparsec of a Strongly Lensed Quasar Host Galaxy at z = 2.8

    International Nuclear Information System (INIS)

    Bayliss, Matthew B.; Bordoloi, Rongmon; Sharon, Keren; Runnoe, Jessie; Johnson, Traci; Paterno-Mahler, Rachel; Acharyya, Ayan; Bian, Fuyan; Kewley, Lisa; Gladders, Michael D.; Rigby, Jane R.; Dahle, Hakon; Florian, Michael

    2017-01-01

    We report the detection of extended Ly α emission from the host galaxy of SDSS J2222+2745, a strongly lensed quasar at z = 2.8. Spectroscopic follow-up clearly reveals extended Ly α in emission between two images of the central active galactic nucleus (AGN). We reconstruct the lensed quasar host galaxy in the source plane by applying a strong lens model to HST imaging and resolve spatial scales as small as ∼200 pc. In the source plane, we recover the host galaxy morphology to within a few hundred parsecs of the central AGN and map the extended Ly α emission to its physical origin on one side of the host galaxy at radii ∼0.5–2 kpc from the central AGN. There are clear morphological differences between the Ly α and rest-frame ultraviolet stellar continuum emission from the quasar host galaxy. Furthermore, the relative velocity profiles of quasar Ly α , host galaxy Ly α , and metal lines in outflowing gas reveal differences in the absorbing material affecting the AGN and host galaxy. These data indicate the presence of patchy local intervening gas in front of the central quasar and its host galaxy. This interpretation is consistent with the central luminous quasar being obscured across a substantial fraction of its surrounding solid angle, resulting in strong anisotropy in the exposure of the host galaxy to ionizing radiation from the AGN. This work demonstrates the power of strong-lensing-assisted studies to probe spatial scales that are currently inaccessible by other means.

  2. Mass Modeling of Frontier Fields Cluster MACS J1149.5+2223 Using Strong and Weak Lensing

    Science.gov (United States)

    Finney, Emily Quinn; Bradač, Maruša; Huang, Kuang-Han; Hoag, Austin; Morishita, Takahiro; Schrabback, Tim; Treu, Tommaso; Borello Schmidt, Kasper; Lemaux, Brian C.; Wang, Xin; Mason, Charlotte

    2018-05-01

    We present a gravitational-lensing model of MACS J1149.5+2223 using ultra-deep Hubble Frontier Fields imaging data and spectroscopic redshifts from HST grism and Very Large Telescope (VLT)/MUSE spectroscopic data. We create total mass maps using 38 multiple images (13 sources) and 608 weak-lensing galaxies, as well as 100 multiple images of 31 star-forming regions in the galaxy that hosts supernova Refsdal. We find good agreement with a range of recent models within the HST field of view. We present a map of the ratio of projected stellar mass to total mass (f ⋆) and find that the stellar mass fraction for this cluster peaks on the primary BCG. Averaging within a radius of 0.3 Mpc, we obtain a value of ={0.012}-0.003+0.004, consistent with other recent results for this ratio in cluster environments, though with a large global error (up to δf ⋆ = 0.005) primarily due to the choice of IMF. We compare values of f ⋆ and measures of star formation efficiency for this cluster to other Hubble Frontier Fields clusters studied in the literature, finding that MACS1149 has a higher stellar mass fraction than these other clusters but a star formation efficiency typical of massive clusters.

  3. The Lyman alpha reference sample

    DEFF Research Database (Denmark)

    Hayes, M.; Östlin, G.; Schaerer, D.

    2013-01-01

    We report on new imaging observations of the Lyman alpha emission line (Lyα), performed with the Hubble Space Telescope, that comprise the backbone of the Lyman alpha Reference Sample. We present images of 14 starburst galaxies at redshifts 0.028

  4. Strong lensing analysis of PLCK G004.5-19.5, a Planck-discovered cluster hosting a radio relic at z = 0.52

    Science.gov (United States)

    Sifón, Cristóbal; Menanteau, Felipe; Hughes, John P.; Carrasco, Mauricio; Barrientos, L. Felipe

    2014-02-01

    Context. The recent discovery of a large number of galaxy clusters using the Sunyaev-Zel'dovich (SZ) effect has opened a new era on the study of the most massive clusters in the Universe. Multiwavelength analyses are required to understand the properties of these new sets of clusters, which are a sensitive probe of cosmology. Aims: We aim for a multiwavelength characterization of PLCK G004.5-19.5, one of the most massive X-ray validated SZ effect-selected galaxy clusters discovered by the Planck satellite. Methods: We have observed PLCK G004.5-19.5 with GMOS on the 8.1 m-Gemini South Telescope for optical imaging and spectroscopy, and performed a strong lensing analysis. We also searched for associated radio emission in published catalogs. Results: An analysis of the optical images confirms that this is a massive cluster, with a dominant central galaxy and an accompanying red sequence of galaxies, plus a 14″-long strong lensing arc. Longslit spectroscopy of six cluster members shows that the cluster is at z = 0.516 ± 0.002. We also targeted the strongly lensed arc, and found zarc = 1.601. We use LensTool to carry out a strong lensing analysis, from which we measure a median Einstein radius θE(zs = 1.6) ≃ 30″ and estimate an enclosed mass ME = 2.45-0.47+0.45 × 1014 M⊙. By extrapolating a Navarro-Frenk-White profile, we find a total mass M500SL = 4.0-1.0+2.1 × 1014 M⊙. We also include a constraint on the mass from previous X-ray observations, which yields a slightly higher mass, M500SL+X = 6.7-1.3+2.6 × 1014 M⊙, consistent with the value from strong lensing alone. Intermediate-resolution radio images from the TIFR GMRT Sky Survey at 150 MHz reveal that PLCK G004.5-19.5 hosts a powerful radio relic on scales ≲500 kpc. Emission at the same location is also detected in low-resolution images at 843 MHz and 1.4 GHz. This is one of the higher redshift radio relics known to date. Based on observations obtained at the Gemini Observatory, which is operated

  5. Combining strong lensing and dynamics in galaxy clusters: integrating MAMPOSSt within LENSTOOL. I. Application on SL2S J02140-0535

    Science.gov (United States)

    Verdugo, T.; Limousin, M.; Motta, V.; Mamon, G. A.; Foëx, G.; Gastaldello, F.; Jullo, E.; Biviano, A.; Rojas, K.; Muñoz, R. P.; Cabanac, R.; Magaña, J.; Fernández-Trincado, J. G.; Adame, L.; De Leo, M. A.

    2016-10-01

    Context. The mass distribution in galaxy clusters and groups is an important cosmological probe. It has become clear in recent years that mass profiles are best recovered when combining complementary probes of the gravitational potential. Strong lensing (SL) is very accurate in the inner regions, but other probes are required to constrain the mass distribution in the outer regions, such as weak lensing or studies of dynamics. Aims: We constrain the mass distribution of a cluster showing gravitational arcs by combining a strong lensing method with a dynamical method using the velocities of its 24 member galaxies. Methods: We present a new framework in which we simultaneously fit SL and dynamical data. The SL analysis is based on the LENSTOOL software and the dynamical analysis uses the MAMPOSSt code, which we integrated into LENSTOOL. After describing the implementation of this new tool, we applied it to the galaxy group SL2S J02140-0535 (zspec = 0.44), which we had previously studied. We used new VLT/FORS2 spectroscopy of multiple images and group members, as well as shallow X-ray data from XMM. Results: We confirm that the observed lensing features in SL2S J02140-0535 belong to different background sources. One of these sources is located at zspec = 1.017 ± 0.001, whereas the other source is located at zspec = 1.628 ± 0.001. With the analysis of our new and our previously reported spectroscopic data, we find 24 secure members for SL2S J02140-0535. Both data sets are well reproduced by a single NFW mass profile; the dark matter halo coincides with the peak of the light distribution, with scale radius, concentration, and mass equal to rs = 82+44-17 kpc, c200 = 10.0+1.7-2.5, and M200 = 1.0+0.5-0.2 × 1014 M⊙ respectively. These parameters are better constrained when we fit SL and dynamical information simultaneously. The mass contours of our best model agrees with the direction defined by the luminosity contours and the X-ray emission of SL2S J02140-0535. The

  6. BRIGHT STRONGLY LENSED GALAXIES AT REDSHIFT z ∼ 6-7 BEHIND THE CLUSTERS ABELL 1703 AND CL0024+16

    International Nuclear Information System (INIS)

    Zheng, W.; Bradley, L. D.; Ford, H. C.; Shu, X.W.; Bouwens, R. J.; Illingworth, G. D.; BenItez, N.; Broadhurst, T.; Zitrin, A.; Frye, B.; Infante, L.; Jee, M. J.; Motta, V.

    2009-01-01

    We report on the discovery of three bright, strongly lensed objects behind Abell 1703 and CL0024+16 from a dropout search over 25 arcmin 2 of deep NICMOS data, with deep ACS optical coverage. They are undetected in the deep ACS images below 8500 A and have clear detections in the J and H bands. Fits to the ACS, NICMOS, and IRAC data yield robust photometric redshifts in the range z ∼ 6-7 and largely rule out the possibility that they are low-redshift interlopers. All three objects are extended, and resolved into a pair of bright knots. The bright i-band dropout in Abell 1703 has an H-band AB magnitude of 23.9, which makes it one of the brightest known galaxy candidates at z > 5.5. Our model fits suggest a young, massive galaxy only ∼60 million years old with a mass of ∼10 10 M sun . The dropout galaxy candidates behind CL0024+16 are separated by 2.''5 (∼2 kpc in the source plane), and have H-band AB magnitudes of 25.0 and 25.6. Lensing models of CL0024+16 suggest that the objects have comparable intrinsic magnitudes of AB ∼27.3, approximately one magnitude fainter than L* at z ∼ 6.5. Their similar redshifts, spectral energy distribution, and luminosities, coupled with their very close proximity on the sky, suggest that they are spatially associated, and plausibly are physically bound. Combining this sample with two previously reported, similarly magnified galaxy candidates at z ∼ 6-8, we find that complex systems with dual nuclei may be a common feature of high-redshift galaxies.

  7. [C II] and {sup 12}CO(1-0) emission maps in HLSJ091828.6+514223: A strongly lensed interacting system at z = 5.24

    Energy Technology Data Exchange (ETDEWEB)

    Rawle, T. D.; Altieri, B. [ESAC, ESA, P.O. Box 78, Villanueva de la Cañada, E-28691 Madrid (Spain); Egami, E.; Rex, M.; Clement, B. [Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States); Bussmann, R. S.; Gurwell, M.; Fazio, G. G. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ivison, R. J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Boone, F. [Université de Toulouse, UPS-OMP, CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France); Combes, F. [Observatoire de Paris, LERMA, CNRS, 61 Av. de l' Observatoire, F-75014 Paris (France); Danielson, A. L. R.; Smail, I.; Swinbank, A. M.; Edge, A. C. [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Richard, J. [CRAL, Université Lyon-1, 9 Av. Charles Andr, F-69561 St Genis Laval (France); Blain, A. W. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Dessauges-Zavadsky, M. [Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290, Sauverny (Switzerland); Jones, T. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Kneib, J.-P., E-mail: tim.rawle@sciops.esa.int [Laboratoire d' Astrophysique EPFL, Observatoire de Sauverny, Versoix 1290 (Switzerland); and others

    2014-03-01

    We present Submillimeter Array [C II] 158 μm and Karl G. Jansky Very Large Array {sup 12}CO(1-0) line emission maps for the bright, lensed, submillimeter source at z = 5.2430 behind A 773: HLSJ091828.6+514223 (HLS0918). We combine these measurements with previously reported line profiles, including multiple {sup 12}CO rotational transitions, [C I], water, and [N II], providing some of the best constraints on the properties of the interstellar medium in a galaxy at z > 5. HLS0918 has a total far-infrared (FIR) luminosity L {sub FIR(8–1000} {sub μm)} = (1.6 ± 0.1) × 10{sup 14} L {sub ☉} μ{sup –1}, where the total magnification μ{sub total} = 8.9 ± 1.9, via a new lens model from the [C II] and continuum maps. Despite a HyLIRG luminosity, the FIR continuum shape resembles that of a local LIRG. We simultaneously fit all of the observed spectral line profiles, finding four components that correspond cleanly to discrete spatial structures identified in the maps. The two most redshifted spectral components occupy the nucleus of a massive galaxy, with a source-plane separation <1 kpc. The reddest dominates the continuum map (demagnified L {sub FIR,} {sub component} = (1.1 ± 0.2) × 10{sup 13} L {sub ☉}) and excites strong water emission in both nuclear components via a powerful FIR radiation field from the intense star formation. A third star-forming component is most likely a region of a merging companion (ΔV ∼ 500 km s{sup –1}) exhibiting generally similar gas properties. The bluest component originates from a spatially distinct region and photodissociation region analysis suggests that it is lower density, cooler, and forming stars less vigorously than the other components. Strikingly, it has very strong [N II] emission, which may suggest an ionized, molecular outflow. This comprehensive view of gas properties and morphology in HLS0918 previews the science possible for a large sample of high-redshift galaxies once ALMA attains full sensitivity.

  8. The effect of stellar evolution uncertainties on the rest-frame ultraviolet stellar lines of C IV and He II in high-redshift Lyman-break galaxies

    Science.gov (United States)

    Eldridge, John J.; Stanway, Elizabeth R.

    2012-01-01

    Young, massive stars dominate the rest-frame ultraviolet (UV) spectra of star-forming galaxies. At high redshifts (z > 2), these rest-frame UV features are shifted into the observed-frame optical and a combination of gravitational lensing, deep spectroscopy and spectral stacking analysis allows the stellar population characteristics of these sources to be investigated. We use our stellar population synthesis code Binary Population and Spectral Synthesis (BPASS) to fit two strong rest-frame UV spectral features in published Lyman-break galaxy spectra, taking into account the effects of binary evolution on the stellar spectrum. In particular, we consider the effects of quasi-homogeneous evolution (arising from the rotational mixing of rapidly rotating stars), metallicity and the relative abundance of carbon and oxygen on the observed strengths of He IIλ1640 Å and C IVλ1548, 1551 Å spectral lines. We find that Lyman-break galaxy spectra at z ˜ 2-3 are best fitted with moderately sub-solar metallicities, and with a depleted carbon-to-oxygen ratio. We also find that the spectra of the lowest metallicity sources are best fitted with model spectra in which the He II emission line is boosted by the inclusion of the effect of massive stars being spun-up during binary mass transfer so these rapidly rotating stars experience quasi-homogeneous evolution.

  9. THE LYMAN ALPHA REFERENCE SAMPLE: EXTENDED LYMAN ALPHA HALOS PRODUCED AT LOW DUST CONTENT

    International Nuclear Information System (INIS)

    Hayes, Matthew; Östlin, Göran; Duval, Florent; Guaita, Lucia; Melinder, Jens; Sandberg, Andreas; Schaerer, Daniel; Verhamme, Anne; Orlitová, Ivana; Mas-Hesse, J. Miguel; Otí-Floranes, Héctor; Adamo, Angela; Atek, Hakim; Cannon, John M.; Herenz, E. Christian; Kunth, Daniel; Laursen, Peter

    2013-01-01

    We report on new imaging observations of the Lyman alpha emission line (Lyα), performed with the Hubble Space Telescope, that comprise the backbone of the Lyman alpha Reference Sample. We present images of 14 starburst galaxies at redshifts 0.028 P20 , Lyα radii are larger than those of Hα by factors ranging from 1 to 3.6, with an average of 2.4. The average ratio of Lyα-to-FUV radii is 2.9. This suggests that much of the Lyα light is pushed to large radii by resonance scattering. Defining the Relative Petrosian Extension of Lyα compared to Hα, ξ Lyα = R Lyα P20 /R Hα P20 , we find ξ Lyα to be uncorrelated with total Lyα luminosity. However, ξ Lyα is strongly correlated with quantities that scale with dust content, in the sense that a low dust abundance is a necessary requirement (although not the only one) in order to spread Lyα photons throughout the interstellar medium and drive a large extended Lyα halo.

  10. Astrophysical Applications of Gravitational Lensing

    Science.gov (United States)

    Mediavilla, Evencio; Muñoz, Jose A.; Garzón, Francisco; Mahoney, Terence J.

    2016-10-01

    Contributors; Participants; Preface; Acknowledgements; 1. Lensing basics Sherry H. Suyu; 2. Exoplanet microlensing Andrew Gould; 3. Case studies of microlensing Veronica Motta and Emilio Falco; 4. Microlensing of quasars and AGN Joachim Wambsganss; 5. DM in clusters and large-scale structure Peter Schneider; 6. The future of strong lensing Chris Fassnacht; 7. Methods for strong lens modelling Charles Keeton; 8. Tutorial on inverse ray shooting Jorge Jimenez-Vicente.

  11. Gravitational lensing

    CERN Document Server

    Dodelson, Scott

    2017-01-01

    Gravitational lensing is a consequence of general relativity, where the gravitational force due to a massive object bends the paths of light originating from distant objects lying behind it. Using very little general relativity and no higher level mathematics, this text presents the basics of gravitational lensing, focusing on the equations needed to understand the phenomena. It then applies them to a diverse set of topics, including multiply imaged objects, time delays, extrasolar planets, microlensing, cluster masses, galaxy shape measurements, cosmic shear, and lensing of the cosmic microwave background. This approach allows undergraduate students and others to get quickly up to speed on the basics and the important issues. The text will be especially relevant as large surveys such as LSST and Euclid begin to dominate the astronomical landscape. Designed for a one semester course, it is accessible to anyone with two years of undergraduate physics background.

  12. Gabor lenses

    International Nuclear Information System (INIS)

    Mobley, R.M.; Gamml, G.; Maschke, A.W.

    1979-01-01

    Stable operation of Gabor lenses has been reported by at least three experimental groups. At Brookhaven, several lens designs have been tried since February, 1978 with very good results. The lens concept is simple, operation is less complicated than anticipated, and the focussing strengths attainable make them very attractive alternatives to magnetic focussing for heavy ion beams at low energies. Results obtained with five different configurations are presented. The lenses work well, concern is now with fine details of their beam-optical performance

  13. Gravitational lenses

    International Nuclear Information System (INIS)

    Turner, E.L.

    1989-01-01

    The author discusses how gravitational lens studies is becoming a major focus of extragalactic astronomy and cosmology. This review is organized into five parts: an overview of the observational situation, a look at the state of theoretical work on lenses, a detailed look at three recently discovered types of lensing phenomena (luminous arcs, radio rings, quasar-galaxy associations), a review of progress on two old problems in lens studies (deriving unique lens mass distribution models, measurements of differential time delays), and an attempt to look into the future of lens studies

  14. Acoustic lenses

    International Nuclear Information System (INIS)

    Kittmer, C.A.

    1983-03-01

    Acoustic lenses focus ultrasound to produce pencil-like beams with reduced near fields. When fitted to conventional (flat-faced) transducers, such lenses greatly improve the ability to detect and size defects. This paper describes a program developed to design acoustic lenses for use in immersion or contact inspection, using normal or angle beam mode with flat or curved targets. Lens surfaces are circular in geometry to facilitate machining. For normal beam inspection of flat plate, spherical or cylindrical lenses are used. For angle beam or curved surface inspections, a compound lens is required to correct for the extra induced aberration. Such a lens is aspherical with one radius of curvature in the plane of incidence, and a different radius of curvature in the plane perpendicular to the incident plane. The resultant beam profile (i.e., location of the acoustic focus, beam diameter, 6 dB working range) depends on the degree of focusing and the transducer used. The operating frequency and bandwidth can be affected by the instrumentation used. Theoretical and measured beam profiles are in good agreement. Various applications, from zone focusing used for defect sizing in thick plate, to line focusing for pipe weld inspection, are discussed

  15. Lyman continuum escape fraction of faint galaxies at z 3.3 in the CANDELS/GOODS-North, EGS, and COSMOS fields with LBC

    Science.gov (United States)

    Grazian, A.; Giallongo, E.; Paris, D.; Boutsia, K.; Dickinson, M.; Santini, P.; Windhorst, R. A.; Jansen, R. A.; Cohen, S. H.; Ashcraft, T. A.; Scarlata, C.; Rutkowski, M. J.; Vanzella, E.; Cusano, F.; Cristiani, S.; Giavalisco, M.; Ferguson, H. C.; Koekemoer, A.; Grogin, N. A.; Castellano, M.; Fiore, F.; Fontana, A.; Marchi, F.; Pedichini, F.; Pentericci, L.; Amorín, R.; Barro, G.; Bonchi, A.; Bongiorno, A.; Faber, S. M.; Fumana, M.; Galametz, A.; Guaita, L.; Kocevski, D. D.; Merlin, E.; Nonino, M.; O'Connell, R. W.; Pilo, S.; Ryan, R. E.; Sani, E.; Speziali, R.; Testa, V.; Weiner, B.; Yan, H.

    2017-06-01

    Context. The reionization of the Universe is one of the most important topics of present-day astrophysical research. The most plausible candidates for the reionization process are star-forming galaxies, which according to the predictions of the majority of the theoretical and semi-analytical models should dominate the H I ionizing background at z ≳ 3. Aims: We measure the Lyman continuum escape fraction, which is one of the key parameters used to compute the contribution of star-forming galaxies to the UV background. It provides the ratio between the photons produced at λ ≤ 912 Å rest-frame and those that are able to reach the inter-galactic medium, I.e. that are not absorbed by the neutral hydrogen or by the dust of the galaxy's inter-stellar medium. Methods: We used ultra-deep U-band imaging (U = 30.2 mag at 1σ) from Large Binocular Camera at the Large Binocular Telescope (LBC/LBT) in the CANDELS/GOODS-North field and deep imaging in the COSMOS and EGS fields in order to estimate the Lyman continuum escape fraction of 69 star-forming galaxies with secure spectroscopic redshifts at 3.27 ≤ z ≤ 3.40 to faint magnitude limits (L = 0.2L∗, or equivalently M1500 - 19). The narrow redshift range implies that the LBC U-band filter exclusively samples the λ ≤ 912 Å rest-frame wavelengths. Results: We measured through stacks a stringent upper limit (L∗), while for the faint population (L = 0.2L∗) the limit to the escape fraction is ≲ 10%. We computed the contribution of star-forming galaxies to the observed UV background at z 3 and find that it is not sufficient to keep the Universe ionized at these redshifts unless their escape fraction increases significantly (≥ 10%) at low luminosities (M1500 ≥ - 19). Conclusions: We compare our results on the Lyman continuum escape fraction of high-z galaxies with recent estimates in the literature, and discuss future prospects to shed light on the end of the Dark Ages. In the future, strong gravitational

  16. The Faint End of the Lyman Alpha Luminosity Function at 2 < z < 3.8

    Science.gov (United States)

    Devarakonda, Yaswant; Livermore, Rachael; Indahl, Briana; Wold, Isak; Davis, Dustin; Finkelstein, Steven

    2018-01-01

    Most current models predict that our universe is mostly composed of small, dim galaxies. Due to these galaxies being so faint, it is very difficult to study these types of galaxies outside of our local universe. This is particularly an issue for studying how these small galaxies evolved over their lifetimes. With the benefit of gravitational lensing, however, we are able to observe galaxies that are farther and fainter than ever before possible. In this particular study, we focus on Lyman-Alpha emitting galaxies between the redshifts of 2-3.8, so that we may study these galaxies during the epoch of peak star formation in the universe. We use the McDonald Observatory 2.7, Harlan Smith telescope with the VIRUS-P IFU spectrograph to observe several Hubble Frontier Field lensing clusters to spectroscopically discover faint galaxies over this redshift range. In addition to providing insight into the faint-end slope of the Lyman alpha luminosity function, the spectroscopic redshifts will allow us to better constrain the mass models of the foreground clusters, such as Abell 370, so that we may better understand lensing effects for this and future studies.

  17. THE LYMAN ALPHA REFERENCE SAMPLE: EXTENDED LYMAN ALPHA HALOS PRODUCED AT LOW DUST CONTENT

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, Matthew [Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France); Oestlin, Goeran; Duval, Florent; Guaita, Lucia; Melinder, Jens; Sandberg, Andreas [Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden); Schaerer, Daniel [CNRS, IRAP, 14, avenue Edouard Belin, F-31400 Toulouse (France); Verhamme, Anne; Orlitova, Ivana [Geneva Observatory, University of Geneva, 51 Chemin des Maillettes, CH-1290 Versoix (Switzerland); Mas-Hesse, J. Miguel; Oti-Floranes, Hector [Centro de Astrobiologia (CSIC-INTA), Departamento de Astrofisica, POB 78, 28691 Villanueva de la Canada (Spain); Adamo, Angela [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Atek, Hakim [Laboratoire d' Astrophysique, Ecole Polytechnique Federale de Lausanne (EPFL), Observatoire, CH-1290 Sauverny (Switzerland); Cannon, John M. [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Herenz, E. Christian [Leibniz-Institut fuer Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Kunth, Daniel [Institut d' Astrophysique de Paris, UMR 7095 CNRS and UPMC, 98 bis Bd Arago, F-75014 Paris (France); Laursen, Peter, E-mail: matthew@astro.su.se [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)

    2013-03-10

    We report on new imaging observations of the Lyman alpha emission line (Ly{alpha}), performed with the Hubble Space Telescope, that comprise the backbone of the Lyman alpha Reference Sample. We present images of 14 starburst galaxies at redshifts 0.028 < z < 0.18 in continuum-subtracted Ly{alpha}, H{alpha}, and the far ultraviolet continuum. We show that Ly{alpha} is emitted on scales that systematically exceed those of the massive stellar population and recombination nebulae: as measured by the Petrosian 20% radius, R{sub P20}, Ly{alpha} radii are larger than those of H{alpha} by factors ranging from 1 to 3.6, with an average of 2.4. The average ratio of Ly{alpha}-to-FUV radii is 2.9. This suggests that much of the Ly{alpha} light is pushed to large radii by resonance scattering. Defining the Relative Petrosian Extension of Ly{alpha} compared to H{alpha}, {xi}{sub Ly{alpha}} = R {sup Ly{alpha}}{sub P20}/R {sup H{alpha}}{sub P20}, we find {xi}{sub Ly{alpha}} to be uncorrelated with total Ly{alpha} luminosity. However, {xi}{sub Ly{alpha}} is strongly correlated with quantities that scale with dust content, in the sense that a low dust abundance is a necessary requirement (although not the only one) in order to spread Ly{alpha} photons throughout the interstellar medium and drive a large extended Ly{alpha} halo.

  18. Molecular gas in the Herschel-selected strongly lensed submillimeter galaxies at z 2-4 as probed by multi-J CO lines

    Science.gov (United States)

    Yang, C.; Omont, A.; Beelen, A.; Gao, Y.; van der Werf, P.; Gavazzi, R.; Zhang, Z.-Y.; Ivison, R.; Lehnert, M.; Liu, D.; Oteo, I.; González-Alfonso, E.; Dannerbauer, H.; Cox, P.; Krips, M.; Neri, R.; Riechers, D.; Baker, A. J.; Michałowski, M. J.; Cooray, A.; Smail, I.

    2017-12-01

    We present the IRAM-30 m observations of multiple-J CO (Jup mostly from 3 up to 8) and [C I](3P2 → 3P1) ([C I](2-1) hereafter) line emission in a sample of redshift 2-4 submillimeter galaxies (SMGs). These SMGs are selected among the brightest-lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). Forty-seven CO lines and 7 [C I](2-1) lines have been detected in 15 lensed SMGs. A non-negligible effect of differential lensing is found for the CO emission lines, which could have caused significant underestimations of the linewidths, and hence of the dynamical masses. The CO spectral line energy distributions (SLEDs), peaking around Jup 5-7, are found to be similar to those of the local starburst-dominated ultra-luminous infrared galaxies and of the previously studied SMGs. After correcting for lensing amplification, we derived the global properties of the bulk of molecular gas in the SMGs using non-LTE radiative transfer modelling, such as the molecular gas density nH2 102.5-104.1 cm-3 and the kinetic temperature Tk 20-750 K. The gas thermal pressure Pth ranging from 105 K cm-3 to 106 K cm-3 is found to be correlated with star formation efficiency. Further decomposing the CO SLEDs into two excitation components, we find a low-excitation component with nH2 102.8-104.6 cm-3 and Tk 20-30 K, which is less correlated with star formation, and a high-excitation one (nH2 102.7-104.2 cm-3, Tk 60-400 K) which is tightly related to the on-going star-forming activity. Additionally, tight linear correlations between the far-infrared and CO line luminosities have been confirmed for the Jup ≥ 5 CO lines of these SMGs, implying that these CO lines are good tracers of star formation. The [C I](2-1) lines follow the tight linear correlation between the luminosities of the [C I](2-1) and the CO(1-0) line found in local starbursts, indicating that [C I] lines could serve as good total molecular gas mass tracers for high-redshift SMGs as well

  19. The DES Bright Arcs Survey: Hundreds of Candidate Strongly Lensed Galaxy Systems from the Dark Energy Survey Science Verification and Year 1 Observations

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, H. T.; Buckley-Geer, E. J.; Lindgren, K. A.; Nord, B.; Gaitsch, H.; Gaitsch, S.; Lin, H.; Allam, S.; Collett, T. E.; Furlanetto, C.; Gill, M. S. S.; More, A.; Nightingale, J.; Odden, C.; Pellico, A.; Tucker, D. L.; Costa, L. N. da; Neto, A. Fausti; Kuropatkin, N.; Soares-Santos, M.; Welch, B.; Zhang, Y.; Frieman, J. A.; Abdalla, F. B.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Cunha, C. E.; D’Andrea, C. B.; Desai, S.; Dietrich, J. P.; Drlica-Wagner, A.; Evrard, A. E.; Finley, D. A.; Flaugher, B.; García-Bellido, J.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; James, D. J.; Kuehn, K.; Kuhlmann, S.; Lahav, O.; Li, T. S.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Menanteau, F.; Miquel, R.; Nichol, R. C.; Nugent, P.; Ogando, R. L. C.; Plazas, A. A.; Reil, K.; Romer, A. K.; Sako, M.; Sanchez, E.; Santiago, B.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.

    2017-09-01

    We report the results of our searches for strong gravitational lens systems in the Dark Energy Survey (DES) Science Verication and Year 1 observations. The Science Verication data spans approximately 250 sq. deg. with median i

  20. The DES Bright Arcs Survey: Hundreds of Candidate Strongly Lensed Galaxy Systems from the Dark Energy Survey Science Verification and Year 1 Observations

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, H. T.; Buckley-Geer, E. J.; Lindgren, K. A.; Nord, B.; Gaitsch, H.; Gaitsch, S.; Lin, H.; Allam, S.; Odden, C.; Pellico, A.; Tucker, D. L.; Kuropatkin, N.; Soares-Santos, M. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Collett, T. E. [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Furlanetto, C.; Nightingale, J. [University of Nottingham, School of Physics and Astronomy, Nottingham NG7 2RD (United Kingdom); Gill, M. S. S. [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); More, A. [Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Costa, L. N. da; Neto, A. Fausti, E-mail: diehl@fnal.gov [Laboratório Interinstitucional de e-Astronomia—LIneA, Rua Gal. José Cristino 77, Rio de Janeiro, RJ—20921-400 (Brazil); Collaboration: DES Collaboration; and others

    2017-09-01

    We report the results of searches for strong gravitational lens systems in the Dark Energy Survey (DES) Science Verification and Year 1 observations. The Science Verification data span approximately 250 sq. deg. with a median i -band limiting magnitude for extended objects (10 σ ) of 23.0. The Year 1 data span approximately 2000 sq. deg. and have an i -band limiting magnitude for extended objects (10 σ ) of 22.9. As these data sets are both wide and deep, they are particularly useful for identifying strong gravitational lens candidates. Potential strong gravitational lens candidate systems were initially identified based on a color and magnitude selection in the DES object catalogs or because the system is at the location of a previously identified galaxy cluster. Cutout images of potential candidates were then visually scanned using an object viewer and numerically ranked according to whether or not we judged them to be likely strong gravitational lens systems. Having scanned nearly 400,000 cutouts, we present 374 candidate strong lens systems, of which 348 are identified for the first time. We provide the R.A. and decl., the magnitudes and photometric properties of the lens and source objects, and the distance (radius) of the source(s) from the lens center for each system.

  1. Characterization of sand lenses embedded in tills

    DEFF Research Database (Denmark)

    Kessler, Timo Christian; Klint, K.E.S.; Nilsson, B.

    2012-01-01

    Tills dominate large parts of the superficial sediments on the Northern hemisphere. These glacial diamictons are extremely heterogeneous and riddled with fractures and lenses of sand or gravel. The frequency and geometry of sand lenses within tills are strongly linked to glaciodynamic processes...

  2. A 30 kpc CHAIN OF ''BEADS ON A STRING'' STAR FORMATION BETWEEN TWO MERGING EARLY TYPE GALAXIES IN THE CORE OF A STRONG-LENSING GALAXY CLUSTER

    Energy Technology Data Exchange (ETDEWEB)

    Tremblay, Grant R.; Davis, Timothy A. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München (Germany); Gladders, Michael D.; Florian, Michael [Department of Astronomy and Astrophysics and Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Baum, Stefi A.; O' Dea, Christopher P.; Cooke, Kevin C. [Chester F. Carlson Center for Imaging Science and School of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, NY 14623 (United States); Bayliss, Matthew B. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Dahle, Håkon [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, N-0315 Oslo (Norway); Rigby, Jane R. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Sharon, Keren [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Soto, Emmaris [Department of Physics, The Catholic University of America, 200 Hannan Hall, Washington, DC 20064 (United States); Wuyts, Eva, E-mail: grant.tremblay@eso.org [Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, Giessenbachstr., D-85741 Garching bei München (Germany)

    2014-08-01

    New Hubble Space Telescope ultraviolet and optical imaging of the strong-lensing galaxy cluster SDSS J1531+3414 (z = 0.335) reveals two centrally dominant elliptical galaxies participating in an ongoing major merger. The interaction is at least somewhat rich in cool gas, as the merger is associated with a complex network of 19 massive superclusters of young stars (or small tidal dwarf galaxies) separated by ∼1 kpc in projection from one another, combining to an estimated total star formation rate of ∼5 M {sub ☉} yr{sup –1}. The resolved young stellar superclusters are threaded by narrow Hα, [O II], and blue excess filaments arranged in a network spanning ∼27 kpc across the two merging galaxies. This morphology is strongly reminiscent of the well-known ''beads on a string'' mode of star formation observed on kiloparsec scales in the arms of spiral galaxies, resonance rings, and in tidal tails between interacting galaxies. Nevertheless, the arrangement of this star formation relative to the nuclei of the two galaxies is difficult to interpret in a dynamical sense, as no known ''beads on a string'' systems associated with kiloparsec-scale tidal interactions exhibit such lopsided morphology relative to the merger participants. In this Letter, we present the images and follow-up spectroscopy and discuss possible physical interpretations for the unique arrangement of the young stellar clusters. While we suggest that this morphology is likely to be dynamically short-lived, a more quantitative understanding awaits necessary multiwavelength follow-up, including optical integral field spectroscopy, ALMA submillimeter interferometry, and Chandra X-ray imaging.

  3. Lyman continuum observations of solar flares

    Science.gov (United States)

    Machado, M. E.; Noyes, R. W.

    1978-01-01

    A study is made of Lyman continuum observations of solar flares, using data obtained by the EUV spectroheliometer on the Apollo Telescope Mount. It is found that there are two main types of flare regions: an overall 'mean' flare coincident with the H-alpha flare region, and transient Lyman continuum kernels which can be identified with the H-alpha and X-ray kernels observed by other authors. It is found that the ground level hydrogen population in flares is closer to LTE than in the quiet sun and active regions, and that the level of Lyman continuum formation is lowered in the atmosphere from a mass column density .000005 g/sq cm in the quiet sun to .0003 g/sq cm in the mean flare, and to .001 g/sq cm in kernels. From these results the amount of chromospheric material 'evaporated' into the high temperature region is derived, which is found to be approximately 10 to the 15th g, in agreement with observations of X-ray emission measures.

  4. Investigations of Galaxy Clusters Using Gravitational Lensing

    Energy Technology Data Exchange (ETDEWEB)

    Wiesner, Matthew P. [Northern Illinois Univ., DeKalb, IL (United States)

    2014-08-01

    In this dissertation, we discuss the properties of galaxy clusters that have been determined using strong and weak gravitational lensing. A galaxy cluster is a collection of galaxies that are bound together by the force of gravity, while gravitational lensing is the bending of light by gravity. Strong lensing is the formation of arcs or rings of light surrounding clusters and weak lensing is a change in the apparent shapes of many galaxies. In this work we examine the properties of several samples of galaxy clusters using gravitational lensing. In Chapter 1 we introduce astrophysical theory of galaxy clusters and gravitational lensing. In Chapter 2 we examine evidence from our data that galaxy clusters are more concentrated than cosmology would predict. In Chapter 3 we investigate whether our assumptions about the number of galaxies in our clusters was valid by examining new data. In Chapter 4 we describe a determination of a relationship between mass and number of galaxies in a cluster at higher redshift than has been found before. In Chapter 5 we describe a model of the mass distribution in one of the ten lensing systems discovered by our group at Fermilab. Finally in Chapter 6 we summarize our conclusions.

  5. Lyman alpha SMM/UVSP absolute calibration and geocoronal correction

    Science.gov (United States)

    Fontenla, Juan M.; Reichmann, Edwin J.

    1987-01-01

    Lyman alpha observations from the Ultraviolet Spectrometer Polarimeter (UVSP) instrument of the Solar Maximum Mission (SMM) spacecraft were analyzed and provide instrumental calibration details. Specific values of the instrument quantum efficiency, Lyman alpha absolute intensity, and correction for geocoronal absorption are presented.

  6. Continuous coherent Lyman-alpha excitation of atomic hydrogen.

    NARCIS (Netherlands)

    Eikema, K.S.E.; Waltz, J.; Hänsch, T.

    2001-01-01

    The first near natural linewidth of the 1S-2P transition in atomic hydrogen was reported with a high degree of accuracy. A high yield of continuous Lyman-α radiation based on four wave mixing in mercury was employed. It was shown that laser cooloing and detection with Lyman-α radiation has excellent

  7. Variability of the Lyman alpha flux with solar activity

    International Nuclear Information System (INIS)

    Lean, J.L.; Skumanich, A.

    1983-01-01

    A three-component model of the solar chromosphere, developed from ground based observations of the Ca II K chromospheric emission, is used to calculate the variability of the Lyman alpha flux between 1969 and 1980. The Lyman alpha flux at solar minimum is required in the model and is taken as 2.32 x 10 11 photons/cm 2 /s. This value occurred during 1975 as well as in 1976 near the commencement of solar cycle 21. The model predicts that the Lyman alpha flux increases to as much as 5 x 10 11 photons/cm 2 /s at the maximum of the solar cycle. The ratio of the average fluxes for December 1979 (cycle maximum) and July 1976 (cycle minimum) is 1.9. During solar maximum the 27-day solar rotation is shown to cause the Lyman alpha flux to vary by as much as 40% or as little as 5%. The model also shows that the Lyman alpha flux varies over intermediate time periods of 2 to 3 years, as well as over the 11-year sunspot cycle. We conclude that, unlike the sunspot number and the 10.7-cm radio flux, the Lyman alpha flux had a variability that was approximately the same during each of the past three cycles. Lyman alpha fluxes calculated by the model are consistent with measurements of the Lyman alpha flux made by 11 of a total of 14 rocket experiments conducted during the period 1969--1980. The model explains satisfactorily the absolute magnitude, long-term trends, and the cycle variability seen in the Lyman alpha irradiances by the OSO 5 satellite experiment. The 27-day variability observed by the AE-E satellite experiment is well reproduced. However, the magntidue of the AE-E 1 Lyman alpha irradiances are higher than the model calculations by between 40% and 80%. We suggest that the assumed calibration of the AE-E irradiances is in error

  8. The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%

    Energy Technology Data Exchange (ETDEWEB)

    Rutkowski, Michael J.; Hayes, Matthew [Department of Astronomy, AlbaNova University Centre, Stockholm University, SE-10691 Stockholm (Sweden); Scarlata, Claudia; Mehta, Vihang [Minnesota Institute for Astrophysics, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States); Henry, Alaina; Hathi, Nimish; Koekemoer, Anton M. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Cohen, Seth; Windhorst, Rogier [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85281 (United States); Teplitz, Harry I. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Haardt, Francesco [DiSAT, Università dellInsubria, via Valleggio 11, I-22100 Como (Italy); Siana, Brian [Department of Physics, University of California, Riverside, CA 92521 (United States)

    2017-06-01

    Recent work suggests that strong emission line, star-forming galaxies (SFGs) may be significant Lyman continuum leakers. We combine archival Hubble Space Telescope broadband ultraviolet and optical imaging (F275W and F606W, respectively) with emission line catalogs derived from WFC3 IR G141 grism spectroscopy to search for escaping Lyman continuum (LyC) emission from homogeneously selected z ∼ 2.5 SFGs. We detect no escaping Lyman continuum from SFGs selected on [O ii] nebular emission ( N = 208) and, within a narrow redshift range, on [O iii]/[O ii]. We measure 1 σ upper limits to the LyC escape fraction relative to the non-ionizing UV continuum from [O ii] emitters, f {sub esc} ≲ 5.6%, and strong [O iii]/[O ii] > 5 ELGs, f {sub esc} ≲ 14.0%. Our observations are not deep enough to detect f {sub esc} ∼ 10% typical of low-redshift Lyman continuum emitters. However, we find that this population represents a small fraction of the star-forming galaxy population at z ∼ 2. Thus, unless the number of extreme emission line galaxies grows substantially to z ≳ 6, such galaxies may be insufficient for reionization. Deeper survey data in the rest-frame ionizing UV will be necessary to determine whether strong line ratios could be useful for pre-selecting LyC leakers at high redshift.

  9. The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%

    International Nuclear Information System (INIS)

    Rutkowski, Michael J.; Hayes, Matthew; Scarlata, Claudia; Mehta, Vihang; Henry, Alaina; Hathi, Nimish; Koekemoer, Anton M.; Cohen, Seth; Windhorst, Rogier; Teplitz, Harry I.; Haardt, Francesco; Siana, Brian

    2017-01-01

    Recent work suggests that strong emission line, star-forming galaxies (SFGs) may be significant Lyman continuum leakers. We combine archival Hubble Space Telescope broadband ultraviolet and optical imaging (F275W and F606W, respectively) with emission line catalogs derived from WFC3 IR G141 grism spectroscopy to search for escaping Lyman continuum (LyC) emission from homogeneously selected z ∼ 2.5 SFGs. We detect no escaping Lyman continuum from SFGs selected on [O ii] nebular emission ( N = 208) and, within a narrow redshift range, on [O iii]/[O ii]. We measure 1 σ upper limits to the LyC escape fraction relative to the non-ionizing UV continuum from [O ii] emitters, f _e_s_c ≲ 5.6%, and strong [O iii]/[O ii] > 5 ELGs, f _e_s_c ≲ 14.0%. Our observations are not deep enough to detect f _e_s_c ∼ 10% typical of low-redshift Lyman continuum emitters. However, we find that this population represents a small fraction of the star-forming galaxy population at z ∼ 2. Thus, unless the number of extreme emission line galaxies grows substantially to z ≳ 6, such galaxies may be insufficient for reionization. Deeper survey data in the rest-frame ionizing UV will be necessary to determine whether strong line ratios could be useful for pre-selecting LyC leakers at high redshift.

  10. A Sounding Rocket Experiment for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)

    Science.gov (United States)

    Kubo, M.; Kano, R.; Kobayashi, K.; Bando, T.; Narukage, N.; Ishikawa, R.; Tsuneta, S.; Katsukawa, Y.; Ishikawa, S.; Suematsu, Y.; Hara, H.; Shimizu, T.; Sakao, T.; Ichimoto, K.; Goto, M.; Holloway, T.; Winebarger, A.; Cirtain, J.; De Pontieu, B.; Casini, R.; Auchère, F.; Trujillo Bueno, J.; Manso Sainz, R.; Belluzzi, L.; Asensio Ramos, A.; Štěpán, J.; Carlsson, M.

    2014-10-01

    A sounding-rocket experiment called the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is presently under development to measure the linear polarization profiles in the hydrogen Lyman-alpha (Lyα) line at 121.567 nm. CLASP is a vacuum-UV (VUV) spectropolarimeter to aim for first detection of the linear polarizations caused by scattering processes and the Hanle effect in the Lyα line with high accuracy (0.1%). This is a fist step for exploration of magnetic fields in the upper chromosphere and transition region of the Sun. Accurate measurements of the linear polarization signals caused by scattering processes and the Hanle effect in strong UV lines like Lyα are essential to explore with future solar telescopes the strength and structures of the magnetic field in the upper chromosphere and transition region of the Sun. The CLASP proposal has been accepted by NASA in 2012, and the flight is planned in 2015.

  11. EDITORIAL: Focus on Gravitational Lensing

    Science.gov (United States)

    Jain, Bhuvnesh

    2007-11-01

    Gravitational lensing emerged as an observational field following the 1979 discovery of a doubly imaged quasar lensed by a foreground galaxy. In the 1980s and '90s dozens of other multiply imaged systems were observed, as well as time delay measurements, weak and strong lensing by galaxies and galaxy clusters, and the discovery of microlensing in our galaxy. The rapid pace of advances has continued into the new century. Lensing is currently one of best techniques for finding and mapping dark matter over a wide range of scales, and also addresses broader cosmological questions such as understanding the nature of dark energy. This focus issue of New Journal of Physics presents a snapshot of current research in some of the exciting areas of lensing. It provides an occasion to look back at the advances of the last decade and ahead to the potential of the coming years. Just about a decade ago, microlensing was discovered through the magnification of stars in our galaxy by invisible objects with masses between that of Jupiter and a tenth the mass of the Sun. Thus a new component of the mass of our galaxy, dubbed MACHOs, was established (though a diffuse, cold dark matter-like component is still needed to make up most of the galaxy mass). More recently, microlensing led to another exciting discovery—of extra-solar planets with masses ranging from about five times that of Earth to that of Neptune. We can expect many more planets to be discovered through ongoing surveys. Microlensing is the best technique for finding Earth mass planets, though it is not as productive overall as other methods and does not allow for follow up observations. Beyond planet hunting, microlensing has enabled us to observe previously inaccessible systems, ranging from the surfaces of other stars to the accretion disks around the black holes powering distant quasars. Galaxies and galaxy clusters at cosmological distances can produce dramatic lensing effects: multiple images of background galaxies

  12. Achromatic X-ray lenses

    International Nuclear Information System (INIS)

    Umbach, Marion

    2009-01-01

    This thesis presents first results on the development of achromatic refractive X-ray lenses which can be used for scientific experiments at synchrotron sources. First of all the different requirements for achromatic X-ray lenses have been worked out. There are different types of lenses, one type can be used for monochromatized sources when the energy is scanned while the spot size should be constant. The other type can be used at beamlines providing a broad energy band. By a combination of focusing and defocusing elements we have developed a lens system that strongly reduces the chromatic aberration of a refractive lens in a given energy range. The great challenge in the X-ray case - in contrast to the visible range - the complex refractive index, which is very similar for the possible materials in the X-ray spectrum. For precise studies a numerical code has been developed, which calculates the different rays on their way through the lenses to the detector plane via raytracing. In this numerical code the intensity distribution in the detector plane has been analyzed for a chromatic and the corresponding achromatic system. By optimization routines for the two different fields of applications specific parameter combinations were found. For the experimental verification an achromatic system has been developed, consisting of biconcave SU-8 lenses and biconvex Nickel Fresnel lenses. Their fabrication was based on the LIGA-process, including a further innovative development, namely the fabrication of two different materials on one wafer. In the experiment at the synchrotron source ANKA the energy was varied in a specific energy range in steps of 0.1 keV. The intensity distribution for the different energies was detected at a certain focal length. For the achromatic system a reduction of the chromatic aberration could be clearly shown. Achromatic refractive X-ray lenses, especially for the use at synchrotron sources, have not been developed so far. As a consequence of the

  13. Fragmentation inside atomic cooling haloes exposed to Lyman-Werner radiation

    Science.gov (United States)

    Regan, John A.; Downes, Turlough P.

    2018-04-01

    Supermassive stars born in pristine environments in the early Universe hold the promise of being the seeds for the supermassive black holes observed as high redshift quasars shortly after the epoch of reionisation. H2 suppression is thought to be crucial in order to negate normal Population III star formation and allow high accretion rates to drive the formation of supermassive stars. Only in the cases where vigorous fragmentation is avoided will a monolithic collapse be successful, giving rise to a single massive central object. We investigate the number of fragmentation sites formed in collapsing atomic cooling haloes subject to various levels of background Lyman-Werner flux. The background Lyman-Werner flux manipulates the chemical properties of the gas in the collapsing halo by destroying H2. We find that only when the collapsing gas cloud shifts from the molecular to the atomic cooling regime is the degree of fragmentation suppressed. In our particular case, we find that this occurs above a critical Lyman-Werner background of J ˜ 10 J21. The important criterion being the transition to the atomic cooling regime rather than the actual value of J, which will vary locally. Once the temperature of the gas exceeds T ≳ 104 K and the gas transitions to atomic line cooling, then vigorous fragmentation is strongly suppressed.

  14. One Episode, Two Lenses

    Science.gov (United States)

    Drijvers, Paul; Godino, Juan D.; Font, Vicenc; Trouche, Luc

    2013-01-01

    A deep understanding of students' learning processes is one of the core challenges of research in mathematics education. To achieve this, different theoretical lenses are available. The question is how these different lenses compare and contrast, and how they can be coordinated and combined to provide a more comprehensive view on the topic of…

  15. Constraining Lyman continuum escape using Machine Learning

    Science.gov (United States)

    Giri, Sambit K.; Zackrisson, Erik; Binggeli, Christian; Pelckmans, Kristiaan; Cubo, Rubén; Mellema, Garrelt

    2018-05-01

    The James Webb Space Telescope (JWST) will observe the rest-frame ultraviolet/optical spectra of galaxies from the epoch of reionization (EoR) in unprecedented detail. While escaping into the intergalactic medium, hydrogen-ionizing (Lyman continuum; LyC) photons from the galaxies will contribute to the bluer end of the UV slope and make nebular emission lines less prominent. We present a method to constrain leakage of the LyC photons using the spectra of high redshift (z >~ 6) galaxies. We simulate JWST/NIRSpec observations of galaxies at z =6-9 by matching the fluxes of galaxies observed in the Frontier Fields observations of galaxy cluster MACS-J0416. Our method predicts the escape fraction fesc with a mean absolute error Δfesc ~ 0.14. The method also predicts the redshifts of the galaxies with an error .

  16. Gravitational lensing of quasars

    CERN Document Server

    Eigenbrod, Alexander

    2013-01-01

    The universe, in all its richness, diversity and complexity, is populated by a myriad of intriguing celestial objects. Among the most exotic of them are gravitationally lensed quasars. A quasar is an extremely bright nucleus of a galaxy, and when such an object is gravitationally lensed, multiple images of the quasar are produced – this phenomenon of cosmic mirage can provide invaluable insights on burning questions, such as the nature of dark matter and dark energy. After presenting the basics of modern cosmology, the book describes active galactic nuclei, the theory of gravitational lensing, and presents a particular numerical technique to improve the resolution of astronomical data. The book then enters the heart of the subject with the description of important applications of gravitational lensing of quasars, such as the measurement of the famous Hubble constant, the determination of the dark matter distribution in galaxies, and the observation of the mysterious inner parts of quasars with much higher r...

  17. Weakly oval electron lense

    International Nuclear Information System (INIS)

    Daumenov, T.D.; Alizarovskaya, I.M.; Khizirova, M.A.

    2001-01-01

    The method of the weakly oval electrical field getting generated by the axially-symmetrical field is shown. Such system may be designed with help of the cylindric form coaxial electrodes with the built-in quadrupole duplet. The singularity of the indicated weakly oval lense consists of that it provides the conducting both mechanical and electronic adjustment. Such lense can be useful for elimination of the near-axis astigmatism in the electron-optical system

  18. Wandering in the Lyman-alpha forest: a study of dark matter-dark radiation interactions

    Energy Technology Data Exchange (ETDEWEB)

    Krall, Rebecca; Cyr-Racine, Francis-Yan; Dvorkin, Cora, E-mail: rkrall@physics.harvard.edu, E-mail: fcyrraci@physics.harvard.edu, E-mail: dvorkin@physics.harvard.edu [Harvard University, Department of Physics, Cambridge, MA 02138 (United States)

    2017-09-01

    The amplitude of large-scale matter fluctuations inferred from the observed Sunyaev-Zeldovich (SZ) cluster mass function and from weak gravitational lensing studies, when taken at face value, is in tension with measurements of the cosmic microwave background (CMB) and baryon acoustic oscillation (BAO). In this work, we revisit whether this possible discrepancy can be attributed to new interactions in the dark matter sector. Focusing on a cosmological model where dark matter interacts with a dark radiation species until the epoch of matter-radiation equality, we find that measurements of the Lyman-alpha flux power spectrum from the Sloan Digital Sky Survey provide no support to the hypothesis that new dark matter interactions can resolve the possible tension between CMB and large-scale structure (LSS). Indeed, while the addition of dark matter-dark radiation interactions leads to an improvement of 2ΔlnL=12 with respect to the standard Λ cold dark matter (ΛCDM) model when only CMB, BAO, and LSS data are considered, the inclusion of Lyman-alpha data reduces the improvement of the fit to 2ΔlnL=6 relative to ΛCDM . We thus conclude that the statistical evidence for new dark matter interactions (largely driven by the Planck SZ dataset) is marginal at best, and likely caused by systematics in the data. We also perform a Fisher forecast analysis for the reach of a future dataset composed of a CMB-S4 experiment combined with the Large Synoptic Survey Telescope galaxy survey. We find that the constraint on the effective number of fluid-like dark radiation species, Δ N {sub fluid}, will be improved by an order of magnitude compared to current bounds.

  19. Wandering in the Lyman-alpha forest: a study of dark matter-dark radiation interactions

    International Nuclear Information System (INIS)

    Krall, Rebecca; Cyr-Racine, Francis-Yan; Dvorkin, Cora

    2017-01-01

    The amplitude of large-scale matter fluctuations inferred from the observed Sunyaev-Zeldovich (SZ) cluster mass function and from weak gravitational lensing studies, when taken at face value, is in tension with measurements of the cosmic microwave background (CMB) and baryon acoustic oscillation (BAO). In this work, we revisit whether this possible discrepancy can be attributed to new interactions in the dark matter sector. Focusing on a cosmological model where dark matter interacts with a dark radiation species until the epoch of matter-radiation equality, we find that measurements of the Lyman-alpha flux power spectrum from the Sloan Digital Sky Survey provide no support to the hypothesis that new dark matter interactions can resolve the possible tension between CMB and large-scale structure (LSS). Indeed, while the addition of dark matter-dark radiation interactions leads to an improvement of 2ΔlnL=12 with respect to the standard Λ cold dark matter (ΛCDM) model when only CMB, BAO, and LSS data are considered, the inclusion of Lyman-alpha data reduces the improvement of the fit to 2ΔlnL=6 relative to ΛCDM . We thus conclude that the statistical evidence for new dark matter interactions (largely driven by the Planck SZ dataset) is marginal at best, and likely caused by systematics in the data. We also perform a Fisher forecast analysis for the reach of a future dataset composed of a CMB-S4 experiment combined with the Large Synoptic Survey Telescope galaxy survey. We find that the constraint on the effective number of fluid-like dark radiation species, Δ N fluid , will be improved by an order of magnitude compared to current bounds.

  20. Direct Detection of The Lyman Continuum of Star-forming Galaxies at z~3

    Science.gov (United States)

    Vasei, Kaveh; Siana, Brian; Shapley, Alice; Alavi, Anahita; Rafelski, Marc

    2018-01-01

    Star-forming galaxies are widely believed to be responsible for the reionization of the Universe and much of the ionizing background at z>3. Therefore, there has been much interest in quantifying the escape fraction of the Lyman continuum (LyC) radiation of the star-forming galaxies. Yet direct detection of LyC has proven to be exceptionally challenging. Despite numerous efforts only 7 galaxies at z2 have been robustly confirmed as LyC leakers. To avoid these challenges many studies use indirect methods to infer the LyC escape fraction. We tested these indirect methods by attempting to detect escaping LyC with a 10-orbit Hubble near-UV (F275W) image that is just below the Lyman limit at the redshift of the Cosmic Horseshoe (a lensed galaxy at z=2.4). We concluded that the measured escape fraction is lower, by more than a factor of five, than the expected escape fraction based on the indirect methods. This emphasizes that indirect determinations should only be interpreted as upper-limits. We also investigated the deepest near-UV Hubble images of the SSA22 field to detect LyC leakage from a large sample of candidate star-forming galaxies at z~3.1, whose redshift was obtained by deep Keck/LRIS spectroscopy and for which Keck narrow-band imaging was showing possible LyC leakage. The high spatial resolution of Hubble images is crucial to confirm our detections are clean from foreground contaminating galaxies, and also to ascertain the escape fraction of our final candidates. We identify five clean LyC emitting star-forming galaxies. The follow up investigation of these galaxies will significantly increase our knowledge of the LyC escape fraction and the mechanisms allowing for LyC escape.

  1. Relative Contribution of the Hydrogen 2 s Two-Photon Decay and Lyman- α Escape Channels during the Epoch of Cosmological Recombination

    Science.gov (United States)

    Rubiño-Martin, J. A.; Sunyaev, R. A.

    2018-01-01

    We discuss the evolution of the ratio in number of recombinations due to 2 s two photon escape and due to the escape of Lyman- α photons from the resonance during the epoch of cosmological recombination, within the width of the last scattering surface and near its boundaries. We discuss how this ratio evolves in time, and how it defines the profile of the Lyman- α line in the spectrum of CMB. One of the key reasons for explaining its time dependence is the strong overpopulation of the 2 p level relative to the 2 s level at redshifts z ≲ 750.

  2. Isolating the Lyman alpha forest BAO anomaly

    Energy Technology Data Exchange (ETDEWEB)

    Evslin, Jarah, E-mail: jarah@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, NanChangLu 509, Lanzhou 730000 (China)

    2017-04-01

    A 2.5-3σ discrepancy has been reported between the baryonic acoustic oscillation peak (BAO) in the Lyman α forest at z ∼ 2.34 and the best fit Planck ΛCDM cosmology. To isolate the origin of the tension, we consider unanchored BAO, in which the standard BAO ruler is not calibrated, eliminating any dependence on cosmology before redshift z ∼ 2.34. We consider BOSS BAO measurements at z ∼ 0.32, 0.57 and 2.34, using the full 2-dimensional constraints on the angular and line of sight BAO scale, as well as isotropic BAO measurements by 6dF and SDSS at z ∼ 0.106 and z ∼ 0.15. We find that the z >0.43 data alone is in 2.9σ of tension with ΛCDM with or without the Planck best fit values of the mass fraction Ω {sub m} and the BAO scale r {sub d} H {sub 0}, indicating that the tension arises not from the ΛCDM parameters but from the dark energy evolution itself at 0.57< z <2.34. This conclusion is supported when the acoustic scale measured by the CMB is included, which further increases the tension and excludes a solution with a constant dark energy equation of state. Including the low z BAO data, which is itself consistent with ΛCDM, reduces the tension to just over 2σ, however in this case a CPL parametrization of the dark energy evolution yields only a modest improvement.

  3. Lyman Limit Absorbers in GALEX Spectra

    Science.gov (United States)

    Williger, Gerard M.; Haberzettl, Lutz G.; Ribaudo, Joseph; Kuchner, Marc J.; Burchett, Joseph; Clowes, Roger G.; Lauroesch, James T.; Mills, Brianna; Borden, Jeremy

    2018-01-01

    We describe the method and early results for crowdsourcing a search for low-redshift partial and complete Lyman Limit Systems (pLLSs and LLSs) in the GALEX spectral archive. LLSs have been found in large numbers at z>3 and traced to lower redshift through a relatively small number of QSO spectra from spaced-based telescopes. From a sample of 44 pLLSs and 11 LLSs at 0.1 = -0.32 +/- 0.07 and the low-metallicity portion centered at = -1.87 +/- 0.11.The GALEX spectral archive offers a vast dataset potentially containing hundreds of LLSs, which may be leveraged to search for such a bimodality and track its evolution within the unconstrained near-UV gap at 1data coverage and signal-to-noise ratio are highly variable, which hampers an automated search. We have therefore begun crowdsourcing a subset of the GALEX archive for LLSs and pLLSs via a Zooniverse project. Initially, undergraduate physics majors are performing a pilot project before releasing to citizen scientists in the public at large. We will then vet candidate systems and estimate column densities in a follow-up analysis. Upon assessing the accuracy of the physics majors’ identifications, the results will be used to devise a larger program with the help of the general public. The resulting data set would then provide the best available link between the HST-selected far-UV and ground-based pLLS+LLS samples and provide an ideal sample for consequent metallicity determinations.

  4. Haro 11: Where is the Lyman Continuum Source?

    Energy Technology Data Exchange (ETDEWEB)

    Keenan, Ryan P.; Oey, M. S. [Department of Astronomy, University of Michigan, 1085 South University Avenue, Ann Arbor, MI 48109 (United States); Jaskot, Anne E. [Department of Astronomy, Smith College, Northampton, MA 01063 (United States); James, Bethan L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2017-10-10

    Identifying the mechanism by which high-energy Lyman continuum (LyC) photons escaped from early galaxies is one of the most pressing questions in cosmic evolution. Haro 11 is the best known local LyC-leaking galaxy, providing an important opportunity to test our understanding of LyC escape. The observed LyC emission in this galaxy presumably originates from one of the three bright, photoionizing knots known as A, B, and C. It is known that Knot C has strong Ly α emission, and Knot B hosts an unusually bright ultraluminous X-ray source, which may be a low-luminosity active galactic nucleus. To clarify the LyC source, we carry out ionization-parameter mapping (IPM) by obtaining narrow-band imaging from the Hubble Space Telescope WFC3 and ACS cameras to construct spatially resolved ratio maps of [O iii]/[O ii] emission from the galaxy. IPM traces the ionization structure of the interstellar medium and allows us to identify optically thin regions. To optimize the continuum subtraction, we introduce a new method for determining the best continuum scale factor derived from the mode of the continuum-subtracted, image flux distribution. We find no conclusive evidence of LyC escape from Knots B or C, but instead we identify a high-ionization region extending over at least 1 kpc from Knot A. This knot shows evidence of an extremely young age (≲1 Myr), perhaps containing very massive stars (>100 M {sub ⊙}). It is weak in Ly α , so if it is confirmed as the LyC source, our results imply that LyC emission may be independent of Ly α emission.

  5. Fresnel's Lighthouse Lenses

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    2007-01-01

    One of the rewards of walking up the scores of steps winding around the inside of the shaft of a lighthouse is turning inward and examining the glass optical system. This arrangement of prisms, lenses, and reflectors is used to project the light from a relatively small source in a beam that can be seen far at sea.

  6. Lyman-continuum leakage as dominant source of diffuse ionized gas in the Antennae galaxy

    Science.gov (United States)

    Weilbacher, Peter M.; Monreal-Ibero, Ana; Verhamme, Anne; Sandin, Christer; Steinmetz, Matthias; Kollatschny, Wolfram; Krajnović, Davor; Kamann, Sebastian; Roth, Martin M.; Erroz-Ferrer, Santiago; Marino, Raffaella Anna; Maseda, Michael V.; Wendt, Martin; Bacon, Roland; Dreizler, Stefan; Richard, Johan; Wisotzki, Lutz

    2018-04-01

    The Antennae galaxy (NGC 4038/39) is the closest major interacting galaxy system and is therefore often studied as a merger prototype. We present the first comprehensive integral field spectroscopic dataset of this system, observed with the MUSE instrument at the ESO VLT. We cover the two regions in this system which exhibit recent star formation: the central galaxy interaction and a region near the tip of the southern tidal tail. In these fields, we detect HII regions and diffuse ionized gas to unprecedented depth. About 15% of the ionized gas was undetected by previous observing campaigns. This newly detected faint ionized gas is visible everywhere around the central merger, and shows filamentary structure. We estimate diffuse gas fractions of about 60% in the central field and 10% in the southern region. We are able to show that the southern region contains a significantly different population of HII regions, showing fainter luminosities. By comparing HII region luminosities with the HST catalog of young star clusters in the central field, we estimate that there is enough Lyman-continuum leakage in the merger to explain the amount of diffuse ionized gas that we detect. We compare the Lyman-continuum escape fraction of each HII region against emission line ratios that are sensitive to the ionization parameter. While we find no systematic trend between these properties, the most extreme line ratios seem to be strong indicators of density bounded ionization. Extrapolating the Lyman-continuum escape fractions to the southern region, we conclude that simply from the comparison of the young stellar populations to the ionized gas there is no need to invoke other ionization mechanisms than Lyman-continuum leaking HII regions for the diffuse ionized gas in the Antennae. FITS images and Table of HII regions are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A95 and at http://muse-vlt.eu/science/antennae/

  7. The Master Lens Database and The Orphan Lenses Project

    Science.gov (United States)

    Moustakas, Leonidas

    2012-10-01

    Strong gravitational lenses are uniquely suited for the study of dark matter structure and substructure within massive halos of many scales, act as gravitational telescopes for distant faint objects, and can give powerful and competitive cosmological constraints. While hundreds of strong lenses are known to date, spanning five orders of magnitude in mass scale, thousands will be identified this decade. To fully exploit the power of these objects presently, and in the near future, we are creating the Master Lens Database. This is a clearinghouse of all known strong lens systems, with a sophisticated and modern database of uniformly measured and derived observational and lens-model derived quantities, using archival Hubble data across several instruments. This Database enables new science that can be done with a comprehensive sample of strong lenses. The operational goal of this proposal is to develop the process and the code to semi-automatically stage Hubble data of each system, create appropriate masks of the lensing objects and lensing features, and derive gravitational lens models, to provide a uniform and fairly comprehensive information set that is ingested into the Database. The scientific goal for this team is to use the properties of the ensemble of lenses to make a new study of the internal structure of lensing galaxies, and to identify new objects that show evidence of strong substructure lensing, for follow-up study. All data, scripts, masks, model setup files, and derived parameters, will be public, and free. The Database will be accessible online and through a sophisticated smartphone application, which will also be free.

  8. Oxygen sensitivity of krypton and Lyman-alpha hygrometers

    NARCIS (Netherlands)

    Dijk, van A.; Kohsiek, W.; Bruin, de H.A.R.

    2003-01-01

    The oxygen sensitivity of krypton and Lyman-¿ hygrometers is studied. Using a dewpoint generator and a controlled nitrogen/oxygen flow the extinction coefficients of five hygrometers associated with the third-order Taylor expansion of the Lambert¿Beer law around reference conditions for oxygen and

  9. Lyman Break Analogs: Constraints on the Formation of Extreme Starbursts at Low and High Redshift

    Science.gov (United States)

    Goncalves, Thiago S.; Overzier, Roderik; Basu-Zych, Antara; Martin, D. Christopher

    2011-01-01

    Lyman Break Analogs (LBAs), characterized by high far-UV luminosities and surface brightnesses as detected by GALEX, are intensely star-forming galaxies in the low-redshift universe (z approximately equal to 0.2), with star formation rates reaching up to 50 times that of the Milky Way. These objects present metallicities, morphologies and other physical properties similar to higher redshift Lyman Break Galaxies (LBGs), motivating the detailed study of LBAs as local laboratories of this high-redshift galaxy population. We present results from our recent integral-field spectroscopy survey of LBAs with Keck/OSIRIS, which shows that these galaxies have the same nebular gas kinematic properties as high-redshift LBGs. We argue that such kinematic studies alone are not an appropriate diagnostic to rule out merger events as the trigger for the observed starburst. Comparison between the kinematic analysis and morphological indices from HST imaging illustrates the difficulties of properly identifying (minor or major) merger events, with no clear correlation between the results using either of the two methods. Artificial redshifting of our data indicates that this problem becomes even worse at high redshift due to surface brightness dimming and resolution loss. Whether mergers could generate the observed kinematic properties is strongly dependent on gas fractions in these galaxies. We present preliminary results of a CARMA survey for LBAs and discuss the implications of the inferred molecular gas masses for formation models.

  10. Direct method gas-phase oxygen abundances of four Lyman break analogs

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Jonathan S.; Croxall, Kevin V.; Pogge, Richard W. [Department of Astronomy, The Ohio State University, Columbus, OH 43201 (United States)

    2014-09-10

    We measure the gas-phase oxygen abundances in four Lyman break analogs using auroral emission lines to derive direct abundances. The direct method oxygen abundances of these objects are generally consistent with the empirically derived strong-line method values, confirming that these objects are low oxygen abundance outliers from the mass-metallicity (MZ) relation defined by star forming Sloan Digital Sky Survey galaxies. We find slightly anomalous excitation conditions (Wolf-Rayet features) that could potentially bias the empirical estimates toward high values if caution is not exercised in the selection of the strong-line calibration. The high rate of star formation and low oxygen abundance of these objects is consistent with the predictions of the fundamental metallicity relation, in which the infall of relatively unenriched gas simultaneously triggers an episode of star formation and dilutes the interstellar medium of the host galaxy.

  11. Gravitational lensing by a Horndeski black hole

    Energy Technology Data Exchange (ETDEWEB)

    Badia, Javier [Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Eiroa, Ernesto F. [Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Universidad de Buenos Aires, Ciudad Universitaria Pabellon I, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina)

    2017-11-15

    In this article we study gravitational lensing by non-rotating and asymptotically flat black holes in Horndeski theory. By adopting the strong deflection limit, we calculate the deflection angle, from which we obtain the positions and the magnifications of the relativistic images. We compare our results with those corresponding to black holes in General Relativity. We analyze the astrophysical consequences in the case of the nearest supermassive black holes. (orig.)

  12. Gravitational lensing by a Horndeski black hole

    International Nuclear Information System (INIS)

    Badia, Javier; Eiroa, Ernesto F.

    2017-01-01

    In this article we study gravitational lensing by non-rotating and asymptotically flat black holes in Horndeski theory. By adopting the strong deflection limit, we calculate the deflection angle, from which we obtain the positions and the magnifications of the relativistic images. We compare our results with those corresponding to black holes in General Relativity. We analyze the astrophysical consequences in the case of the nearest supermassive black holes. (orig.)

  13. Observations of gravitational lenses

    International Nuclear Information System (INIS)

    Fort, B.

    1990-01-01

    During the last tow years a burst of results has come from radio and optical surveys of ''galaxy lenses'' (where the main deflector is a galaxy). These are reviewed. On the other hand, in September 1985 we pointed out a very strange blue ring-like structure on a Charge-Coupled Device image of the cluster of galaxies Abell 370. This turned out to be Einstein arcs discovery. Following this discovery, new observational results have shown that many rich clusters of galaxies can produce numerous arclets: tangentially distorted images of an extremely faint galaxy population probably located at redshift larger than 1. This new class of gravitational lenses proves to be an important observational topic and this will be discussed in the second part of the paper. (author)

  14. The effect of weak lensing on distance estimates from supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Mathew; Maartens, Roy [Department of Physics, University of the Western Cape, Cape Town 7535 (South Africa); Bacon, David J.; Nichol, Robert C.; Campbell, Heather; D' Andrea, Chris B. [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Clarkson, Chris [Astrophysics, Cosmology and Gravity Centre (ACGC), Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701 (South Africa); Bassett, Bruce A. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935 (South Africa); Cinabro, David [Wayne State University, Department of Physics and Astronomy, Detroit, MI 48202 (United States); Finley, David A.; Frieman, Joshua A. [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Galbany, Lluis [CENTRA Centro Multidisciplinar de Astrofísica, Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisbon (Portugal); Garnavich, Peter M. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Olmstead, Matthew D. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Shapiro, Charles [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, La Canada Flintridge, CA 91109 (United States); Sollerman, Jesper, E-mail: matsmith2@gmail.com [The Oskar Klein Centre, Department of Astronomy, AlbaNova, SE-106 91 Stockholm (Sweden)

    2014-01-01

    Using a sample of 608 Type Ia supernovae from the SDSS-II and BOSS surveys, combined with a sample of foreground galaxies from SDSS-II, we estimate the weak lensing convergence for each supernova line of sight. We find that the correlation between this measurement and the Hubble residuals is consistent with the prediction from lensing (at a significance of 1.7σ). Strong correlations are also found between the residuals and supernova nuisance parameters after a linear correction is applied. When these other correlations are taken into account, the lensing signal is detected at 1.4σ. We show, for the first time, that distance estimates from supernovae can be improved when lensing is incorporated, by including a new parameter in the SALT2 methodology for determining distance moduli. The recovered value of the new parameter is consistent with the lensing prediction. Using cosmic microwave background data from WMAP7, H {sub 0} data from Hubble Space Telescope and Sloan Digital Sky Survey (SDSS) Baryon acoustic oscillations measurements, we find the best-fit value of the new lensing parameter and show that the central values and uncertainties on Ω {sub m} and w are unaffected. The lensing of supernovae, while only seen at marginal significance in this low-redshift sample, will be of vital importance for the next generation of surveys, such as DES and LSST, which will be systematics-dominated.

  15. Detections of Planets in Binaries Through the Channel of Chang–Refsdal Gravitational Lensing Events

    Energy Technology Data Exchange (ETDEWEB)

    Han, Cheongho [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Shin, In-Gu; Jung, Youn Kil [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)

    2017-02-01

    Chang–Refsdal (C–R) lensing, which refers to the gravitational lensing of a point mass perturbed by a constant external shear, provides a good approximation in describing lensing behaviors of either a very wide or a very close binary lens. C–R lensing events, which are identified by short-term anomalies near the peak of high-magnification lensing light curves, are routinely detected from lensing surveys, but not much attention is paid to them. In this paper, we point out that C–R lensing events provide an important channel to detect planets in binaries, both in close and wide binary systems. Detecting planets through the C–R lensing event channel is possible because the planet-induced perturbation occurs in the same region of the C–R lensing-induced anomaly and thus the existence of the planet can be identified by the additional deviation in the central perturbation. By presenting the analysis of the actually observed C–R lensing event OGLE-2015-BLG-1319, we demonstrate that dense and high-precision coverage of a C–R lensing-induced perturbation can provide a strong constraint on the existence of a planet in a wide range of planet parameters. The sample of an increased number of microlensing planets in binary systems will provide important observational constraints in giving shape to the details of planet formation, which have been restricted to the case of single stars to date.

  16. Additive manufacturing of tunable lenses

    Science.gov (United States)

    Schlichting, Katja; Novak, Tobias; Heinrich, Andreas

    2017-02-01

    Individual additive manufacturing of optical systems based on 3D Printing offers varied possibilities in design and usage. In addition to the additive manufacturing procedure, the usage of tunable lenses allows further advantages for intelligent optical systems. Our goal is to bring the advantages of additive manufacturing together with the huge potential of tunable lenses. We produced tunable lenses as a bundle without any further processing steps, like polishing. The lenses were designed and directly printed with a 3D Printer as a package. The design contains the membrane as an optical part as well as the mechanical parts of the lens, like the attachments for the sleeves which contain the oil. The dynamic optical lenses were filled with an oil. The focal length of the lenses changes due to a change of the radius of curvature. This change is caused by changing the pressure in the inside of the lens. In addition to that, we designed lenses with special structures to obtain different areas with an individual optical power. We want to discuss the huge potential of this technology for several applications. Further, an appropriate controlling system is needed. Wéll show the possibilities to control and regulate the optical power of the lenses. The lenses could be used for illumination tasks, and in the future, for individual measurement tasks. The main advantage is the individuality and the possibility to create an individual design which completely fulfills the requirements for any specific application.

  17. Lensing of 21-cm fluctuations by primordial gravitational waves.

    Science.gov (United States)

    Book, Laura; Kamionkowski, Marc; Schmidt, Fabian

    2012-05-25

    Weak-gravitational-lensing distortions to the intensity pattern of 21-cm radiation from the dark ages can be decomposed geometrically into curl and curl-free components. Lensing by primordial gravitational waves induces a curl component, while the contribution from lensing by density fluctuations is strongly suppressed. Angular fluctuations in the 21-cm background extend to very small angular scales, and measurements at different frequencies probe different shells in redshift space. There is thus a huge trove of information with which to reconstruct the curl component of the lensing field, allowing tensor-to-scalar ratios conceivably as small as r~10(-9)-far smaller than those currently accessible-to be probed.

  18. Weighing the Low-Redshift Lyman-alpha Forest

    Science.gov (United States)

    Shull, Mike

    2005-01-01

    In 2003-2004, our FUSE research group prepared several major surveys of the amount of baryonic matter in the intergalactic medium (IGM), using the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. These surveys include measurements of the Lyman-alpha absorption line of neutral hydrogen (H I), the far-ultraviolet (1032,1038 Angstrom) doublet of highly ionized oxygen ( O VI), the higher Lyman-series lines (Ly-beta, Ly-gamma, etc) of H I, and the 977 Angstrom line of c III. As an overview, our FUSE spectroscopic studies, taken together with data from the Hubble Space Telescope, show that approximately 30% of the normal matter is contained in intergalactic hydrogen gas clouds (the Lyman-alpha forest). Another 5-10% resides in hotter gas at temperatures of 10(exp 5) to 10(exp 6) K, visible in 0 VI and C III absorption. Along with the matter attributed to galaxies, we have now accounted for approximately HALF of all the baryonic matter in the universe. Where is the other half? That matter my exist in even hotter gas, invisible through the ultraviolet absorption lines, but perhaps detectable through X-ray absorption lines of more highly ionized oxygen and neon.

  19. Chromospheric Lyman-alpha spectro-polarimeter (CLASP)

    Science.gov (United States)

    Kano, Ryouhei; Bando, Takamasa; Narukage, Noriyuki; Ishikawa, Ryoko; Tsuneta, Saku; Katsukawa, Yukio; Kubo, Masahito; Ishikawa, Shin-nosuke; Hara, Hirohisa; Shimizu, Toshifumi; Suematsu, Yoshinori; Ichimoto, Kiyoshi; Sakao, Taro; Goto, Motoshi; Kato, Yoshiaki; Imada, Shinsuke; Kobayashi, Ken; Holloway, Todd; Winebarger, Amy; Cirtain, Jonathan; De Pontieu, Bart; Casini, Roberto; Trujillo Bueno, Javier; Štepán, Jiří; Manso Sainz, Rafael; Belluzzi, Luca; Asensio Ramos, Andres; Auchère, Frédéric; Carlsson, Mats

    2012-09-01

    One of the biggest challenges in heliophysics is to decipher the magnetic structure of the solar chromosphere. The importance of measuring the chromospheric magnetic field is due to both the key role the chromosphere plays in energizing and structuring the outer solar atmosphere and the inability of extrapolation of photospheric fields to adequately describe this key boundary region. Over the last few years, significant progress has been made in the spectral line formation of UV lines as well as the MHD modeling of the solar atmosphere. It is found that the Hanle effect in the Lyman-alpha line (121.567 nm) is a most promising diagnostic tool for weaker magnetic fields in the chromosphere and transition region. Based on this groundbreaking research, we propose the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) to NASA as a sounding rocket experiment, for making the first measurement of the linear polarization produced by scattering processes and the Hanle effect in the Lyman-alpha line (121.567 nm), and making the first exploration of the magnetic field in the upper chromosphere and transition region of the Sun. The CLASP instrument consists of a Cassegrain telescope, a rotating 1/2-wave plate, a dual-beam spectrograph assembly with a grating working as a beam splitter, and an identical pair of reflective polarization analyzers each equipped with a CCD camera. We propose to launch CLASP in December 2014.

  20. Weak lensing and CMB: Parameter forecasts including a running spectral index

    International Nuclear Information System (INIS)

    Ishak, Mustapha; Hirata, Christopher M.; McDonald, Patrick; Seljak, Uros

    2004-01-01

    We use statistical inference theory to explore the constraints from future galaxy weak lensing (cosmic shear) surveys combined with the current CMB constraints on cosmological parameters, focusing particularly on the running of the spectral index of the primordial scalar power spectrum, α s . Recent papers have drawn attention to the possibility of measuring α s by combining the CMB with galaxy clustering and/or the Lyman-α forest. Weak lensing combined with the CMB provides an alternative probe of the primordial power spectrum. We run a series of simulations with variable runnings and compare them to semianalytic nonlinear mappings to test their validity for our calculations. We find that a 'reference' cosmic shear survey with f sky =0.01 and 6.6x10 8 galaxies per steradian can reduce the uncertainty on n s and α s by roughly a factor of 2 relative to the CMB alone. We investigate the effect of shear calibration biases on lensing by including the calibration factor as a parameter, and show that for our reference survey, the precision of cosmological parameter determination is only slightly degraded even if the amplitude calibration is uncertain by as much as 5%. We conclude that in the near future weak lensing surveys can supplement the CMB observations to constrain the primordial power spectrum

  1. RHIC electron lenses upgrades

    Energy Technology Data Exchange (ETDEWEB)

    Gu, X. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Altinbas, Z. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Bruno, D. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Binello, S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Costanzo, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Drees, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Gassner, D. M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Hock, J. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Hock, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Harvey, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Marusic, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Mi, C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Michnoff, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Miller, T. A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Pikin, A. I. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Samms, T. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Shrey, T. C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Tan, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Than, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Thieberger, P. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; White, S. M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2015-05-03

    In the Relativistic Heavy Ion Collider (RHIC) 100 GeV polarized proton run in 2015, two electron lenses were used to partially compensate for the head-on beam-beam effect for the first time. Here, we describe the design of the current electron lens, detailing the hardware modifications made after the 2014 commissioning run with heavy ions. A new electron gun with 15-mm diameter cathode is characterized. The electron beam transverse profile was measured using a YAG screen and fitted with a Gaussian distribution. During operation, the overlap of the electron and proton beams was achieved using the electron backscattering detector in conjunction with an automated orbit control program.

  2. Stationary inverted Lyman population formed from incandescently heated hydrogen gas with certain catalysts

    International Nuclear Information System (INIS)

    Mills, Randell L; Ray, Paresh C; Mayo, Robert M

    2003-01-01

    A new chemically generated plasma source is reported. The presence of gaseous Rb + or K + ions with thermally dissociated hydrogen formed a low applied temperature, extremely low voltage plasma called a resonant transfer or rt-plasma having strong vacuum ultraviolet emission. We propose an energetic catalytic reaction involving a resonant energy transfer between hydrogen atoms and Rb + or 2K + since Rb + to Rb 2+ , 2K + to K + K 2+ , and K to K 3+ each provide a reaction with a net enthalpy equal to the potential energy of atomic hydrogen. Remarkably, a stationary inverted Lyman population was observed; thus, these catalytic reactions may pump a cw HI laser as predicted by a collisional radiative model used to determine that the observed overpopulation was above threshold

  3. Stationary inverted Lyman population formed from incandescently heated hydrogen gas with certain catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Randell L; Ray, Paresh C; Mayo, Robert M [BlackLight Power, Inc., 493 Old Trenton Road, Cranbury, NJ 08512 (United States)

    2003-07-07

    A new chemically generated plasma source is reported. The presence of gaseous Rb{sup +} or K{sup +} ions with thermally dissociated hydrogen formed a low applied temperature, extremely low voltage plasma called a resonant transfer or rt-plasma having strong vacuum ultraviolet emission. We propose an energetic catalytic reaction involving a resonant energy transfer between hydrogen atoms and Rb{sup +} or 2K{sup +} since Rb{sup +} to Rb{sup 2+}, 2K{sup +} to K + K{sup 2+}, and K to K{sup 3+} each provide a reaction with a net enthalpy equal to the potential energy of atomic hydrogen. Remarkably, a stationary inverted Lyman population was observed; thus, these catalytic reactions may pump a cw HI laser as predicted by a collisional radiative model used to determine that the observed overpopulation was above threshold.

  4. Magnetic electron lenses

    CERN Document Server

    1982-01-01

    No single volume has been entirely devoted to the properties of magnetic lenses, so far as I am aware, although of course all the numerous textbooks on electron optics devote space to them. The absence of such a volume, bringing together in­ formation about the theory and practical design of these lenses, is surprising, for their introduction some fifty years ago has created an entirely new family of commercial instruments, ranging from the now traditional transmission electron microscope, through the reflection and transmission scanning microscopes, to co­ lumns for micromachining and microlithography, not to mention the host of experi­ mental devices not available commercially. It therefore seemed useful to prepare an account of the various aspects of mag­ netic lens studies. These divide naturally into the five chapters of this book: the theoretical background, in which the optical behaviour is described and formu­ lae given for the various aberration coefficients; numerical methods for calculat­ ing...

  5. Gravitational lenses and cosmological evolution

    International Nuclear Information System (INIS)

    Peacock, J.A.

    1982-01-01

    The effect of gravitational lensing on the apparent cosmological evolution of extragalactic radio sources is investigated. Models for a lens population consisting of galaxies and clusters of galaxies are constructed and used to calculate the distribution of amplification factors caused by lensing. Although many objects at high redshifts are predicted to have flux densities altered by 10 to 20 per cent relative to a homogeneous universe, flux conservation implies that de-amplification is as common as amplification. The effects on cosmological evolution as inferred from source counts and redshift data are thus relatively small; the slope of the counts is not large enough for intrinsically rare lensing events of high amplitude to corrupt observed samples. Lensing effects may be of greater importance for optically selected quasars, where lenses of mass as low as approximately 10 -4 solar mass can cause large amplifications. (author)

  6. LENSING NOISE IN MILLIMETER-WAVE GALAXY CLUSTER SURVEYS

    International Nuclear Information System (INIS)

    Hezaveh, Yashar; Vanderlinde, Keith; Holder, Gilbert; De Haan, Tijmen

    2013-01-01

    We study the effects of gravitational lensing by galaxy clusters of the background of dusty star-forming galaxies (DSFGs) and the cosmic microwave background (CMB), and examine the implications for Sunyaev-Zel'dovich-based (SZ) galaxy cluster surveys. At the locations of galaxy clusters, gravitational lensing modifies the probability distribution of the background flux of the DSFGs as well as the CMB. We find that, in the case of a single-frequency 150 GHz survey, lensing of DSFGs leads both to a slight increase (∼10%) in detected cluster number counts (due to a ∼50% increase in the variance of the DSFG background, and hence an increased Eddington bias) and a rare (occurring in ∼2% of clusters) 'filling-in' of SZ cluster signals by bright strongly lensed background sources. Lensing of the CMB leads to a ∼55% reduction in CMB power at the location of massive galaxy clusters in a spatially matched single-frequency filter, leading to a net decrease in detected cluster number counts. We find that the increase in DSFG power and decrease in CMB power due to lensing at cluster locations largely cancel, such that the net effect on cluster number counts for current SZ surveys is subdominant to Poisson errors

  7. Beryllium parabolic refractive x-ray lenses

    International Nuclear Information System (INIS)

    Lengeler, B.; Schroer, C.G.; Kuhlmann, M.; Benner, B.; Guenzler, T.F.; Kurapova, O.; Somogyi, A.; Snigirev, A.; Snigireva, I.

    2004-01-01

    Parabolic refractive x-ray lenses are novel optical components for the hard x-ray range from about 5 keV to about 120 keV. They focus in both directions. They are compact, robust, and easy to align and to operate. They can be used like glass lenses are used for visible light, the main difference being that the numerical aperture N.A. is much smaller than 1 (of order 10-4 to 10-3). Their main applications are in micro- and nanofocusing, in imaging by absorption and phase contrast and in fluorescence mode. In combination with tomography they allow for 3-dimensional imaging of opaque media with submicrometer resolution. Finally, they can be used in speckle spectroscopy by means of coherent x-ray scattering. Beryllium as lens material strongly enhances the transmission and the field of view as compared to aluminium. With increased N.A. the lateral resolution is also considerably improved with Be lenses. References to a number of applications are given

  8. First Constraints on Fuzzy Dark Matter from Lyman-α Forest Data and Hydrodynamical Simulations.

    Science.gov (United States)

    Iršič, Vid; Viel, Matteo; Haehnelt, Martin G; Bolton, James S; Becker, George D

    2017-07-21

    We present constraints on the masses of extremely light bosons dubbed fuzzy dark matter (FDM) from Lyman-α forest data. Extremely light bosons with a de Broglie wavelength of ∼1  kpc have been suggested as dark matter candidates that may resolve some of the current small scale problems of the cold dark matter model. For the first time, we use hydrodynamical simulations to model the Lyman-α flux power spectrum in these models and compare it to the observed flux power spectrum from two different data sets: the XQ-100 and HIRES/MIKE quasar spectra samples. After marginalization over nuisance and physical parameters and with conservative assumptions for the thermal history of the intergalactic medium (IGM) that allow for jumps in the temperature of up to 5000 K, XQ-100 provides a lower limit of 7.1×10^{-22}  eV, HIRES/MIKE returns a stronger limit of 14.3×10^{-22}  eV, while the combination of both data sets results in a limit of 20×10^{-22}  eV (2σ C.L.). The limits for the analysis of the combined data sets increases to 37.5×10^{-22}  eV (2σ C.L.) when a smoother thermal history is assumed where the temperature of the IGM evolves as a power law in redshift. Light boson masses in the range 1-10×10^{-22}  eV are ruled out at high significance by our analysis, casting strong doubts that FDM helps solve the "small scale crisis" of the cold dark matter models.

  9. QUANTIFYING THE BIASES OF SPECTROSCOPICALLY SELECTED GRAVITATIONAL LENSES

    International Nuclear Information System (INIS)

    Arneson, Ryan A.; Brownstein, Joel R.; Bolton, Adam S.

    2012-01-01

    Spectroscopic selection has been the most productive technique for the selection of galaxy-scale strong gravitational lens systems with known redshifts. Statistically significant samples of strong lenses provide a powerful method for measuring the mass-density parameters of the lensing population, but results can only be generalized to the parent population if the lensing selection biases are sufficiently understood. We perform controlled Monte Carlo simulations of spectroscopic lens surveys in order to quantify the bias of lenses relative to parent galaxies in velocity dispersion, mass axis ratio, and mass-density profile. For parameters typical of the SLACS and BELLS surveys, we find (1) no significant mass axis ratio detection bias of lenses relative to parent galaxies; (2) a very small detection bias toward shallow mass-density profiles, which is likely negligible compared to other sources of uncertainty in this parameter; (3) a detection bias toward smaller Einstein radius for systems drawn from parent populations with group- and cluster-scale lensing masses; and (4) a lens-modeling bias toward larger velocity dispersions for systems drawn from parent samples with sub-arcsecond mean Einstein radii. This last finding indicates that the incorporation of velocity-dispersion upper limits of non-lenses is an important ingredient for unbiased analyses of spectroscopically selected lens samples. In general, we find that the completeness of spectroscopic lens surveys in the plane of Einstein radius and mass-density profile power-law index is quite uniform, up to a sharp drop in the region of large Einstein radius and steep mass-density profile, and hence that such surveys are ideally suited to the study of massive field galaxies.

  10. USING THE BULLET CLUSTER AS A GRAVITATIONAL TELESCOPE TO STUDY z ∼> 7 LYMAN BREAK GALAXIES

    International Nuclear Information System (INIS)

    Hall, Nicholas; Bradač, Maruša; Gonzalez, Anthony H.; Treu, Tommaso; Clowe, Douglas; Jones, Christine; Stiavelli, Massimo; Zaritsky, Dennis; Cuby, Jean-Gabriel; Clément, Benjamin

    2012-01-01

    We use imaging obtained with the Hubble Space Telescope Wide Field Camera 3 to search for z 850 dropouts at z ∼ 7 and J 110 dropouts at z ∼ 9 lensed by the Bullet Cluster. In total we find 10 z 850 dropouts in our 8.27 arcmin 2 field. Using magnification maps from a combined weak- and strong-lensing mass reconstruction of the Bullet Cluster and correcting for estimated completeness levels, we calculate the surface density and luminosity function of our z 850 dropouts as a function of intrinsic (accounting for magnification) magnitude. We find results consistent with published blank field surveys, despite using much shallower data, and demonstrate the effectiveness of cluster surveys in the search for z ∼ 7 galaxies.

  11. CLASH: DISCOVERY OF A BRIGHT z {approx_equal} 6.2 DWARF GALAXY QUADRUPLY LENSED BY MACS J0329.6-0211

    Energy Technology Data Exchange (ETDEWEB)

    Zitrin, A. [Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, Heidelberg (Germany); Moustakas, J. [Center for Astrophysics and Space Sciences, University of California, San Diego, CA (United States); Bradley, L.; Coe, D.; Postman, M.; Koekemoer, A. [Space Telescope Science Institute, Baltimore, MD (United States); Moustakas, L. A. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA (United States); Shu, X. [Department of Astronomy, University of Science and Technology of China, Hefei, Anhui (China); Zheng, W.; Ford, H. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD (United States); Benitez, N. [Instituto de Astrofisica de Andalucia (CSIC), Granada (Spain); Bouwens, R. [Leiden Observatory, University of Leiden, Leiden (Netherlands); Broadhurst, T. [Department of Theoretical Physics, University of Basque Country, Bilbao (Spain); Host, O.; Jouvel, S. [Department of Physics and Astronomy, University College London, London (United Kingdom); Meneghetti, M. [INAF, Osservatorio Astronomico di Bologna, Bologna (Italy); Rosati, P. [European Southern Observatory, Garching bei Muenchen (Germany); Donahue, M. [Physics and Astronomy Department, Michigan State University, East Lansing, MI (United States); Grillo, C. [Excellence Cluster Universe, Technische Universitaet Muenchen, Muenchen (Germany); Kelson, D., E-mail: adizitrin@gmail.com [Observatories of the Carnegie Institution of Washington, Pasadena, CA (United States); and others

    2012-03-15

    We report the discovery of a z{sub phot} = 6.18{sup +0.05}{sub -0.07} (95% confidence level) dwarf galaxy, lensed into four images by the galaxy cluster MACS J0329.6-0211 (z{sub l} = 0.45). The galaxy is observed as a high-redshift dropout in HST/ACS/WFC3 CLASH and Spitzer/IRAC imaging. Its redshift is securely determined due to a clear detection of the Lyman break in the 18-band photometry, making this galaxy one of the highest-redshift multiply lensed objects known to date with an observed magnitude of F125W =24.00 {+-} 0.04 AB mag for its most magnified image. We also present the first strong-lensing analysis of this cluster uncovering 15 additional multiply imaged candidates of five lower-redshift sources spanning the range z{sub s} {approx_equal} 2-4. The mass model independently supports the high photometric redshift and reveals magnifications of 11.6{sup +8.9}{sub -4.1}, 17.6{sup +6.2}{sub -3.9}, 3.9{sup +3.0}{sub -1.7}, and 3.7{sup +1.3}{sub -0.2}, respectively, for the four images of the high-redshift galaxy. By delensing the most magnified image we construct an image of the source with a physical resolution of {approx}200 pc when the universe was {approx}0.9 Gyr old, where the z {approx_equal} 6.2 galaxy occupies a source-plane area of approximately 2.2 kpc{sup 2}. Modeling the observed spectral energy distribution using population synthesis models, we find a demagnified stellar mass of {approx}10{sup 9} M{sub Sun }, subsolar metallicity (Z/Z{sub Sun} {approx} 0.5), low dust content (A{sub V} {approx} 0.1 mag), a demagnified star formation rate (SFR) of {approx}3.2 M{sub Sun} yr{sup -1}, and a specific SFR of {approx}3.4 Gyr{sup -1}, all consistent with the properties of local dwarf galaxies.

  12. CMB lensing and giant rings

    Energy Technology Data Exchange (ETDEWEB)

    Rathaus, Ben; Itzhaki, Nissan, E-mail: nitzhaki@post.tau.ac.il, E-mail: ben.rathaus@gmail.com [Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel-Aviv University, Ramat-Aviv, 69978 (Israel)

    2012-05-01

    We study the CMB lensing signature of a pre-inationary particle (PIP), assuming it is responsible for the giant rings anomaly that was found recently in the WMAP data. Simulating Planck-like data we find that generically the CMB lensing signal to noise ratio associated with such a PIP is quite small and it would be difficult to cross correlate the temperature giant rings with the CMB lensing signal. However, if the pre-inationary particle is also responsible for the bulk flow measured from the local large scale structure, which happens to point roughly at the same direction as the giant rings, then the CMB lensing signal to noise ratio is fairly significant.

  13. KINOFORM LENSES - TOWARD NANOMETER RESOLUTION.

    Energy Technology Data Exchange (ETDEWEB)

    STEIN, A.; EVANS-LUTTERODT, K.; TAYLOR, A.

    2004-10-23

    While hard x-rays have wavelengths in the nanometer and sub-nanometer range, the ability to focus them is limited by the quality of sources and optics, and not by the wavelength. A few options, including reflective (mirrors), diffractive (zone plates) and refractive (CRL's) are available, each with their own limitations. Here we present our work with kinoform lenses which are refractive lenses with all material causing redundant 2{pi} phase shifts removed to reduce the absorption problems inherently limiting the resolution of refractive lenses. By stacking kinoform lenses together, the effective numerical aperture, and thus the focusing resolution, can be increased. The present status of kinoform lens fabrication and testing at Brookhaven is presented as well as future plans toward achieving nanometer resolution.

  14. [O III] EMISSION AND GAS KINEMATICS IN A LYMAN-ALPHA BLOB AT z {approx} 3.1

    Energy Technology Data Exchange (ETDEWEB)

    McLinden, Emily M. [McDonald Observatory, University of Texas at Austin, Austin, TX 78712 (United States); Malhotra, Sangeeta; Rhoads, James E. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Hibon, Pascale [Gemini Observatory, La Serena (Chile); Weijmans, Anne-Marie [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Tilvi, Vithal [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States)

    2013-04-10

    We present spectroscopic measurements of the [O III] emission line from two subregions of strong Ly{alpha} emission in a radio-quiet Lyman-alpha blob (LAB). The blob under study is LAB1 at z {approx} 3.1, and the [O III] detections are from the two Lyman break galaxies (LBGs) embedded in the blob halo. The [O III] measurements were made with LUCIFER on the 8.4 m Large Binocular Telescope and NIRSPEC on 10 m Keck Telescope. Comparing the redshift of the [O III] measurements to Ly{alpha} redshifts from SAURON allows us to take a step toward understanding the kinematics of the gas in the blob. Using both LUCIFER and NIRSPEC we find velocity offsets between the [O III] and Ly{alpha} redshifts that are modestly negative or consistent with 0 km s{sup -1} in both subregions studied (ranging from -72 {+-} 42- + 6 {+-} 33 km s{sup -1}). A negative offset means Ly{alpha} is blueshifted with respect to [O III] a positive offset then implies Ly{alpha} is redshifted with respect to [O III]. These results may imply that outflows are not primarily responsible for Lyman alpha escape in this LAB, since outflows are generally expected to produce a positive velocity offset. In addition, we present an [O III] line flux upper limit on a third region of LAB1, a region that is unassociated with any underlying galaxy. We find that the [O III] upper limit from the galaxy-unassociated region of the blob is at least 1.4-2.5 times fainter than the [O III] flux from one of the LBG-associated regions and has an [O III] to Ly{alpha} ratio measured at least 1.9-3.4 times smaller than the same ratio measured from one of the LBGs.

  15. The z~4 Lyman Break Galaxies: Colors and Theoretical Predictions

    Science.gov (United States)

    Idzi, Rafal; Somerville, Rachel; Papovich, Casey; Ferguson, Henry C.; Giavalisco, Mauro; Kretchmer, Claudia; Lotz, Jennifer

    2004-01-01

    We investigate several fundamental properties of z~4 Lyman break galaxies by comparing observations with the predictions of a semianalytic model based on the cold dark matter theory of hierarchical structure formation. We use a sample of B435-dropouts from the Great Observatories Origins Deep Survey and complement the Advanced Camera for Surveys optical B435, V606, i775, and z850 data with the Very Large Telescope Infrared Spectrometer and Array Camera J, H, and Ks observations. We extract B435-dropouts from our semianalytic mock catalog using the same color criteria and magnitude limits that were applied to the observed sample. We find that the i775-Ks colors of the model-derived and observed B435-dropouts are in good agreement. However, we find that the i775-z850 colors differ significantly, indicating perhaps that either too little dust or an incorrect extinction curve has been used. Motivated by the reasonably good agreement between the model and observed data, we present predictions for the stellar masses, star formation rates, and ages for the z~4 Lyman break sample. We find that according to our model, the color selection criteria used to select our z~4 sample surveys 67% of all galaxies at this epoch down to z850Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555. Based on observations collected at the European Southern Observatory, Chile (ESO programmes 168.A-0485, 64.0-0643, 66.A-0572, and 68.A-0544).

  16. Red nuggets grow inside-out: evidence from gravitational lensing

    NARCIS (Netherlands)

    Oldham, Lindsay; Auger, Matthew W.; Fassnacht, Christopher D.; Treu, Tommaso; Brewer, Brendon J.; Koopmans, L. V. E.; Lagattuta, David; Marshall, Philip; McKean, John; Vegetti, Simona

    We present a new sample of strong gravitational lens systems where both the foreground lenses and background sources are early-type galaxies. Using imaging from Hubble Space Telescope (HST)/Advanced Camera for Studies (ACS) and Keck/NIRC2, we model the surface brightness distributions and show that

  17. On an illusion of superluminal velocities produced by gravitational lenses

    International Nuclear Information System (INIS)

    Ingel, L.Kh.

    1981-01-01

    It is noted that gravitational lenses, by focusing the radiation of an object, increase the angle which it subtends. This in turn produces the illusion of an increase in velocities at right angles to the line of sight. Preliminary estimates are made which indicate a rather high probability of strong distortion of the observed velocities

  18. Cosmology with weak lensing surveys

    International Nuclear Information System (INIS)

    Munshi, Dipak; Valageas, Patrick; Waerbeke, Ludovic van; Heavens, Alan

    2008-01-01

    Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening matter. The distortions are due to fluctuations in the gravitational potential, and are directly related to the distribution of matter and to the geometry and dynamics of the Universe. As a consequence, weak gravitational lensing offers unique possibilities for probing the Dark Matter and Dark Energy in the Universe. In this review, we summarise the theoretical and observational state of the subject, focussing on the statistical aspects of weak lensing, and consider the prospects for weak lensing surveys in the future. Weak gravitational lensing surveys are complementary to both galaxy surveys and cosmic microwave background (CMB) observations as they probe the unbiased non-linear matter power spectrum at modest redshifts. Most of the cosmological parameters are accurately estimated from CMB and large-scale galaxy surveys, so the focus of attention is shifting to understanding the nature of Dark Matter and Dark Energy. On the theoretical side, recent advances in the use of 3D information of the sources from photometric redshifts promise greater statistical power, and these are further enhanced by the use of statistics beyond two-point quantities such as the power spectrum. The use of 3D information also alleviates difficulties arising from physical effects such as the intrinsic alignment of galaxies, which can mimic weak lensing to some extent. On the observational side, in the next few years weak lensing surveys such as CFHTLS, VST-KIDS and Pan-STARRS, and the planned Dark Energy Survey, will provide the first weak lensing surveys covering very large sky areas and depth. In the long run even more ambitious programmes such as DUNE, the Supernova Anisotropy Probe (SNAP) and Large-aperture Synoptic Survey Telescope (LSST) are planned. Weak lensing of diffuse components such as the CMB and 21 cm emission can also

  19. Cosmology with weak lensing surveys

    Energy Technology Data Exchange (ETDEWEB)

    Munshi, Dipak [Institute of Astronomy, Madingley Road, Cambridge, CB3 OHA (United Kingdom); Astrophysics Group, Cavendish Laboratory, Madingley Road, Cambridge CB3 OHE (United Kingdom)], E-mail: munshi@ast.cam.ac.uk; Valageas, Patrick [Service de Physique Theorique, CEA Saclay, 91191 Gif-sur-Yvette (France); Waerbeke, Ludovic van [University of British Columbia, Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Heavens, Alan [SUPA - Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)

    2008-06-15

    Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening matter. The distortions are due to fluctuations in the gravitational potential, and are directly related to the distribution of matter and to the geometry and dynamics of the Universe. As a consequence, weak gravitational lensing offers unique possibilities for probing the Dark Matter and Dark Energy in the Universe. In this review, we summarise the theoretical and observational state of the subject, focussing on the statistical aspects of weak lensing, and consider the prospects for weak lensing surveys in the future. Weak gravitational lensing surveys are complementary to both galaxy surveys and cosmic microwave background (CMB) observations as they probe the unbiased non-linear matter power spectrum at modest redshifts. Most of the cosmological parameters are accurately estimated from CMB and large-scale galaxy surveys, so the focus of attention is shifting to understanding the nature of Dark Matter and Dark Energy. On the theoretical side, recent advances in the use of 3D information of the sources from photometric redshifts promise greater statistical power, and these are further enhanced by the use of statistics beyond two-point quantities such as the power spectrum. The use of 3D information also alleviates difficulties arising from physical effects such as the intrinsic alignment of galaxies, which can mimic weak lensing to some extent. On the observational side, in the next few years weak lensing surveys such as CFHTLS, VST-KIDS and Pan-STARRS, and the planned Dark Energy Survey, will provide the first weak lensing surveys covering very large sky areas and depth. In the long run even more ambitious programmes such as DUNE, the Supernova Anisotropy Probe (SNAP) and Large-aperture Synoptic Survey Telescope (LSST) are planned. Weak lensing of diffuse components such as the CMB and 21 cm emission can also

  20. Prescribing prophylactic antibiotics to users of therapeutic contact lenses.

    Science.gov (United States)

    Colomé-Campos, J; Quevedo-Junyent, L; Godoy-Barreda, N; Martínez-Salcedo, I; Romero-Aroca, P

    2013-03-01

    To describe the benefits and optimum use of prophylactic antibiotics in users of therapeutic contact lenses (TCL). A microbiological study was carried out on samples from 33 patients who continuously wore TCL. The resistance to antibiotics of bacteria isolated in our health region was also reviewed. An assessment was also made on whether there were microorganisms of a higher pathogenic potential in TCL than conventional contact lenses, as reported in the literature. No bacteria were isolated from 17 (52%) of the 33 lenses studied. From the 16 (48%) remaining lenses, coagulase negative Staphylococci were isolated from 10 (62%), Propionibacterium acnes from 4 (25%), and Corynebacterium from 2 (13%). The high number of negative cultures and the presence of saprophytic bacteria indicate that prophylactic antibiotic treatment is not precise. The most frequent pathogenic bacteria found in contact lenses are strongly resistant to the current commercially available antibiotics. Copyright © 2012 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  1. Lyman series profiles: From laser-plasmas to white dwarf stars

    Energy Technology Data Exchange (ETDEWEB)

    Kielkopf, J.F. [University of Louisville, Louisville, Kentucky 40292 (United States); Allard, N.F. [Observatoire de Paris-Meudon, France and Institut d Astrophysique, Paris (France)

    1999-04-01

    The low energy interactions of neutral and ionized hydrogen atoms are fundamental processes which also have important applications to the diagnostics of laboratory and astrophysical plasmas. Satellites in the far wings of Lyman {alpha} and Lyman {beta} have been identified as ultraviolet absorption features in the spectra of white dwarf and {lambda} Bootis stars, and they are seen in the emission spectra of plasmas produced when a pulsed laser excites a target H{sub 2} gas. The observed Lyman series profiles agree with unified line shape theory which includes variation of the dipole transition moment during the radiative collision. {copyright} {ital 1999 American Institute of Physics.}

  2. Statistics of gravitational lenses. III. Astrophysical consequences of quasar lensing

    International Nuclear Information System (INIS)

    Ostriker, J.P.; Vietri, M.

    1986-01-01

    The method of Schmidt and Green (1983) for calculating the luminosity function of quasars is combined with gravitational-lensing theory to compute expected properties of lensed systems. Multiple quasar images produced by galaxies are of order 0.001 of the observed quasars, with the numbers over the whole sky calculated to be (0.86, 120, 1600) to limiting B magnitudes of (16, 19, 22). The amount of false evolution is small except for an interesting subset of apparently bright, large-redshift objects for which minilensing by starlike objects may be important. Some of the BL Lac objects may be in this category, with the galaxy identified as the parent object really a foreground object within which stars have lensed a background optically violent variable quasar. 24 references

  3. NO OVERDENSITY OF LYMAN-ALPHA EMITTING GALAXIES AROUND A QUASAR AT z  ∼ 5.7

    International Nuclear Information System (INIS)

    Mazzucchelli, C.; Bañados, E.; Decarli, R.; Farina, E. P.; Venemans, B. P.; Walter, F.; Overzier, R.

    2017-01-01

    Bright quasars, observed when the universe was less than one billion years old ( z  > 5.5), are known to host massive black holes (∼10 9 M ⊙ ) and are thought to reside in the center of massive dark matter overdensities. In this picture, overdensities of galaxies are expected around high-redshift quasars. However, observations based on the detection of Lyman-break galaxies (LBGs) around these quasars do not offer a clear picture: this may be due to the uncertain redshift constraints of LBGs, which are solely selected through broadband filters. To circumvent such uncertainties, we here perform a search for Lyman-alpha emitting galaxies (LAEs) in the field of the quasar PSO J215.1512–16.0417 at z  ∼ 5.73, through narrowband deep imaging with FORS2 at the Very Large Telescope. We study an area of 37 arcmin 2 , i.e., ∼206 comoving Mpc 2 at the redshift of the quasar. We find no evidence of an overdensity of LAEs in the quasar field with respect to blank-field studies. Possible explanations for these findings may be that our survey volume is too small, or that the strong ionizing radiation from the quasar hinders galaxy formation in its immediate proximity. Another possibility is that these quasars are not situated in the dense environments predicted by some simulations.

  4. NO OVERDENSITY OF LYMAN-ALPHA EMITTING GALAXIES AROUND A QUASAR AT z  ∼ 5.7

    Energy Technology Data Exchange (ETDEWEB)

    Mazzucchelli, C.; Bañados, E.; Decarli, R.; Farina, E. P.; Venemans, B. P.; Walter, F. [Max Planck Institute für Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Overzier, R. [Observatório Nacional, Rua José Cristino, 77. CEP 20921-400, São Cristóvão, Rio de Janeiro-RJ (Brazil)

    2017-01-01

    Bright quasars, observed when the universe was less than one billion years old ( z  > 5.5), are known to host massive black holes (∼10{sup 9} M {sub ⊙}) and are thought to reside in the center of massive dark matter overdensities. In this picture, overdensities of galaxies are expected around high-redshift quasars. However, observations based on the detection of Lyman-break galaxies (LBGs) around these quasars do not offer a clear picture: this may be due to the uncertain redshift constraints of LBGs, which are solely selected through broadband filters. To circumvent such uncertainties, we here perform a search for Lyman-alpha emitting galaxies (LAEs) in the field of the quasar PSO J215.1512–16.0417 at z  ∼ 5.73, through narrowband deep imaging with FORS2 at the Very Large Telescope. We study an area of 37 arcmin{sup 2}, i.e., ∼206 comoving Mpc{sup 2} at the redshift of the quasar. We find no evidence of an overdensity of LAEs in the quasar field with respect to blank-field studies. Possible explanations for these findings may be that our survey volume is too small, or that the strong ionizing radiation from the quasar hinders galaxy formation in its immediate proximity. Another possibility is that these quasars are not situated in the dense environments predicted by some simulations.

  5. Contact Lenses for Color Blindness.

    Science.gov (United States)

    Badawy, Abdel-Rahman; Hassan, Muhammad Umair; Elsherif, Mohamed; Ahmed, Zubair; Yetisen, Ali K; Butt, Haider

    2018-06-01

    Color vision deficiency (color blindness) is an inherited genetic ocular disorder. While no cure for this disorder currently exists, several methods can be used to increase the color perception of those affected. One such method is the use of color filtering glasses which are based on Bragg filters. While these glasses are effective, they are high cost, bulky, and incompatible with other vision correction eyeglasses. In this work, a rhodamine derivative is incorporated in commercial contact lenses to filter out the specific wavelength bands (≈545-575 nm) to correct color vision blindness. The biocompatibility assessment of the dyed contact lenses in human corneal fibroblasts and human corneal epithelial cells shows no toxicity and cell viability remains at 99% after 72 h. This study demonstrates the potential of the dyed contact lenses in wavelength filtering and color vision deficiency management. © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Lensing smoothing of BAO wiggles

    Energy Technology Data Exchange (ETDEWEB)

    Dio, Enea Di, E-mail: enea.didio@oats.inaf.it [INAF—Osservatorio Astronomico di Trieste, Via G.B. Tiepolo 11, I-34143 Trieste (Italy)

    2017-03-01

    We study non-perturbatively the effect of the deflection angle on the BAO wiggles of the matter power spectrum in real space. We show that from redshift z ∼2 this introduces a dispersion of roughly 1 Mpc at BAO scale, which corresponds approximately to a 1% effect. The lensing effect induced by the deflection angle, which is completely geometrical and survey independent, smears out the BAO wiggles. The effect on the power spectrum amplitude at BAO scale is about 0.1 % for z ∼2 and 0.2 % for z ∼4. We compare the smoothing effects induced by the lensing potential and non-linear structure formation, showing that the two effects become comparable at z ∼ 4, while the lensing effect dominates for sources at higher redshifts. We note that this effect is not accounted through BAO reconstruction techniques.

  7. Diagnostics of the Solar Wind and Global Heliosphere with Lyman-α Emission Measurements

    Science.gov (United States)

    Provornikova, E. P.; Izmodenov, V. V.; Laming, J. M.; Strachan, L.; Wood, B. E.; Katushkina, O. A.; Ko, Y.-K.; Tun Beltran, S.; Chakrabarti, S.

    2018-02-01

    We propose to develop an instrument measuring full sky intensity maps and spectra of interplanetary Lyman-α emission to reveal the global solar wind variability and the nature of the heliosphere and the local interstellar medium.

  8. Aspheric lenses for terahertz imaging.

    Science.gov (United States)

    Lo, Yat Hei; Leonhardt, Rainer

    2008-09-29

    We present novel designs for aspheric lenses used in terahertz (THz) imaging. As different surfaces result in different beam shaping properties and in different losses from reflection and absorption, the resultant imaging resolution (i.e. the focal spot size) depends critically on the design approach. We evaluate the different lens designs using Kirchhoff's scalar diffraction theory, and test the predictions experimentally. We also show that our lenses can achieve sub-wavelength resolution. While our lens designs are tested with THz radiation, the design considerations are applicable also to other regions of the electro-magnetic spectrum.

  9. Gravitational lensing by spinning and radially moving lenses

    International Nuclear Information System (INIS)

    Sereno, M.

    2002-01-01

    The effect of currents of mass on bending of light rays is considered in the weak field regime. Following Fermat's principle and the standard theory of gravitational lensing, we derive the gravito-magnetic correction to time delay function and deflection angle caused by a geometrically-thin lens. The cases of both rotating and shifting deflectors are discussed

  10. A reliable cw Lyman-α laser source for future cooling of antihydrogen

    International Nuclear Information System (INIS)

    Kolbe, Daniel; Beczkowiak, Anna; Diehl, Thomas; Koglbauer, Andreas; Sattler, Matthias; Stappel, Matthias; Steinborn, Ruth; Walz, Jochen

    2012-01-01

    We demonstrate a reliable continuous-wave (cw) laser source at the 1 S–2 P transition in (anti)hydrogen at 121.56 nm (Lyman-α) based on four-wave sum-frequency mixing in mercury. A two-photon resonance in the four-wave mixing scheme is essential for a powerful cw Lyman-α source and is well investigated.

  11. A reliable cw Lyman-{alpha} laser source for future cooling of antihydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Kolbe, Daniel, E-mail: kolbed@uni-mainz.de; Beczkowiak, Anna; Diehl, Thomas; Koglbauer, Andreas; Sattler, Matthias; Stappel, Matthias; Steinborn, Ruth; Walz, Jochen [Johannes Gutenberg-Universitaet, Institut fuer Physik (Germany)

    2012-12-15

    We demonstrate a reliable continuous-wave (cw) laser source at the 1 S-2 P transition in (anti)hydrogen at 121.56 nm (Lyman-{alpha}) based on four-wave sum-frequency mixing in mercury. A two-photon resonance in the four-wave mixing scheme is essential for a powerful cw Lyman-{alpha} source and is well investigated.

  12. Discovery of a very Lyman-α-luminous quasar at z = 6.62.

    Science.gov (United States)

    Koptelova, Ekaterina; Hwang, Chorng-Yuan; Yu, Po-Chieh; Chen, Wen-Ping; Guo, Jhen-Kuei

    2017-02-02

    Distant luminous quasars provide important information on the growth of the first supermassive black holes, their host galaxies and the epoch of reionization. The identification of quasars is usually performed through detection of their Lyman-α line redshifted to 0.9 microns at z > 6.5. Here, we report the discovery of a very Lyman-α luminous quasar, PSO J006.1240 + 39.2219 at redshift z = 6.618, selected based on its red colour and multi-epoch detection of the Lyman-α emission in a single near-infrared band. The Lyman-α line luminosity of PSO J006.1240 + 39.2219 is unusually high and estimated to be 0.8 × 10 12 Solar luminosities (about 3% of the total quasar luminosity). The Lyman-α emission of PSO J006.1240 + 39.2219 shows fast variability on timescales of days in the quasar rest frame, which has never been detected in any of the known high-redshift quasars. The high luminosity of the Lyman-α line, its narrow width and fast variability resemble properties of local Narrow-Line Seyfert 1 galaxies which suggests that the quasar is likely at the active phase of the black hole growth accreting close or even beyond the Eddington limit.

  13. DYNAMIC SPECTRAL MAPPING OF INTERSTELLAR PLASMA LENSES

    Energy Technology Data Exchange (ETDEWEB)

    Tuntsov, Artem V.; Walker, Mark A. [Manly Astrophysics, 3/22 Cliff Street, Manly 2095 (Australia); Koopmans, Leon V. E. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, NL-9700 AV Groningen (Netherlands); Bannister, Keith W.; Stevens, Jamie; Johnston, Simon [CSIRO Astronomy and Space Science, P.O. Box 76, Epping NSW 1710 (Australia); Reynolds, Cormac; Bignall, Hayley E., E-mail: Artem.Tuntsov@manlyastrophysics.org, E-mail: Mark.Walker@manlyastrophysics.org, E-mail: koopmans@astro.rug.nl [International Centre for Radio Astronomy Research—Curtin University, Perth (Australia)

    2016-02-01

    Compact radio sources sometimes exhibit intervals of large, rapid changes in their flux density, due to lensing by interstellar plasma crossing the line of sight. A novel survey program has made it possible to discover these “Extreme Scattering Events” (ESEs) in real time, resulting in a high-quality dynamic spectrum of an ESE observed in PKS 1939–315. Here we present a method for determining the column-density profile of a plasma lens, given only the dynamic radio spectrum of the lensed source, under the assumption that the lens is either axisymmetric or totally anisotropic. Our technique relies on the known, strong frequency dependence of the plasma refractive index in order to determine how points in the dynamic spectrum map to positions on the lens. We apply our method to high-frequency (4.2–10.8 GHz) data from the Australia Telescope Compact Array of the PKS 1939–315 ESE. The derived electron column-density profiles are very similar for the two geometries we consider, and both yield a good visual match to the data. However, the fit residuals are substantially above the noise level, and deficiencies are evident when we compare the predictions of our model to lower-frequency (1.6–3.1 GHz) data on the same ESE, thus motivating future development of more sophisticated inversion techniques.

  14. Nanoplasmonic lenses for bacteria sorting (Presentation Recording)

    Science.gov (United States)

    Zhu, Xiangchao; Yanik, Ahmet A.

    2015-08-01

    We demonstrate that patches of two dimensional arrays of circular plasmonic nanoholes patterned on gold-titanium thin film enables subwavelength focusing of visible light in far field region. Efficient coupling of the light with the excited surface plasmon at metal dielectric interface results in strong light transmission. As a result, surface plasmon plays an important role in the far field focusing behavior of the nanohole-aperture patches device. Furthermore, the focal length of the focused beam was found to be predominantly dependent on the overall size of the patch, which is in good agreement with that calculated by Rayleigh-Sommerfield integral formula. The focused light beam can be utilized to separate bio-particles in the dynamic range from 0.1 μm to 1 μm through mainly overcoming the drag force induced by fluid flow. In our proposed model, focused light generated by our plasmonic lenses will push the larger bio-particles in size back to the source of fluid flow and allow the smaller particles to move towards the central aperture of the patch. Such a new kind of plasmonic lenses open up possibility of sorting bacterium-like particles with plasmonic nanolenses, and also represent a promising tool in the field of virology.

  15. Probing supervoids with weak lensing

    Science.gov (United States)

    Higuchi, Yuichi; Inoue, Kaiki Taro

    2018-05-01

    The cosmic microwave background (CMB) has non-Gaussian features in the temperature fluctuations. An anomalous cold spot surrounded with a hot ring, called the Cold Spot, is one of such features. If a large underdense region (supervoid) resides towards the Cold Spot, we would be able to detect a systematic shape distortion in the images of background source galaxies via weak lensing effect. In order to estimate the detectability of such signals, we used the data of N-body simulations to simulate full-sky ray-tracing of source galaxies. We searched for a most prominent underdense region using the simulated convergence maps smoothed at a scale of 20° and obtained tangential shears around it. The lensing signal expected in a concordant Λ cold dark matter model can be detected at a signal-to-noise ratio S/N ˜ 3. If a supervoid with a radius of ˜200 h-1 Mpc and a density contrast δ0 ˜ -0.3 at the centre resides at a redshift z ˜ 0.2, on-going and near-future weak gravitational lensing surveys would detect a lensing signal with S/N ≳ 4 without resorting to stacking. From the tangential shear profile, we can obtain a constraint on the projected mass distribution of the supervoid.

  16. Weak lensing and dark energy

    International Nuclear Information System (INIS)

    Huterer, Dragan

    2002-01-01

    We study the power of upcoming weak lensing surveys to probe dark energy. Dark energy modifies the distance-redshift relation as well as the matter power spectrum, both of which affect the weak lensing convergence power spectrum. Some dark-energy models predict additional clustering on very large scales, but this probably cannot be detected by weak lensing alone due to cosmic variance. With reasonable prior information on other cosmological parameters, we find that a survey covering 1000 sq deg down to a limiting magnitude of R=27 can impose constraints comparable to those expected from upcoming type Ia supernova and number-count surveys. This result, however, is contingent on the control of both observational and theoretical systematics. Concentrating on the latter, we find that the nonlinear power spectrum of matter perturbations and the redshift distribution of source galaxies both need to be determined accurately in order for weak lensing to achieve its full potential. Finally, we discuss the sensitivity of the three-point statistics to dark energy

  17. Optics Demonstrations Using Cylindrical Lenses

    Science.gov (United States)

    Ivanov, Dragia; Nikolov, Stefan

    2015-01-01

    In this paper we consider the main properties of cylindrical lenses and propose several demonstrational experiments that can be performed with them. Specifically we use simple glasses full of water to demonstrate some basic geometrical optics principles and phenomena. We also present some less standard experiments that can be performed with such…

  18. Scientific visualization of gravitational lenses

    International Nuclear Information System (INIS)

    Magallon, M.

    1999-01-01

    Concepts related to gravitational lenses are discussed and applied to develop an interactive visualization tool that allow us to investigate them. Optimization strategies were performed to elaborate the tool. Some results obtained from the application of the tool are shown [es

  19. Evidence for Black Hole Growth in Local Analogs to Lyman Break Galaxies

    Science.gov (United States)

    Jia, Jianjun; Ptak, Andrew; Heckman, Timothy M.; Overzier, Roderik A.; Hornschemeier, Ann; LaMassa, Stephanie M.

    2011-01-01

    We have used XMM-Newton to observe six Lyman break analogs (LBAs): members of the rare population of local galaxies that have properties that are very similar to distant Lyman break galaxies. Our six targets were specifically selected because they have optical emission-line properties that are intermediate between starbursts and Type 2 (obscured) active galactic nuclei (AGNs). Our new X-ray data provide an important diagnostic of the presence of an AGN. We find X-ray luminosities of order 10(sup 42) erg per second and ratios of X-ray to far-IR lummositles that are higher than values in pure starburst galaxies by factors ranging from approximately 3 to 30. This strongly suggests the presence of an AGN in at least some of the galaxies. The ratios of the luminosities of the hard (2-10 keV) X-ray to [O III] emission line are low by about an order of magnitude compared with Type 1 AGN, but are consistent with the broad range seen in Type 2 AGN. Either the AGN hard X-rays are significantly obscured or the [O III] emission is dominated by the starburst. We searched for an iron emission line at approximately 6.4 ke V, which is a key feature of obscured AGNs, but only detected emission at the approximately 2sigma level. Finally, we find that the ratios of the mid-infrared (24 micrometer) continuum to [O III]lambda 5007 luminosities in these LBAs are higher than the values for Type 2 AGN by an average of 0.8 dex. Combining all these clues, we conclude that an AGN is likely to be present, but that the bolometric luminosity is produced primarily by an intense starburst. If these black holes are radiating at the Eddington limit, their masses would lie in the range of 10(sup 5) - 10(sup 6) solar mass. These objects may offer ideal local laboratories to investigate the processes by which black holes grew in the early universe.

  20. The escape of Lyman photons from a young starburst: the case of Haro11†

    Science.gov (United States)

    Hayes, Matthew; Östlin, Göran; Atek, Hakim; Kunth, Daniel; Mas-Hesse, J. Miguel; Leitherer, Claus; Jiménez-Bailón, Elena; Adamo, Angela

    2007-12-01

    Lyman α (Lyα) is one of the dominant tools used to probe the star-forming galaxy population at high redshift (z). However, astrophysical interpretations of data drawn from Lyα alone hinge on the Lyα escape fraction which, due to the complex radiative transport, may vary greatly. Here, we map the Lyα emission from the local luminous blue compact galaxy Haro11, a known emitter of Lyα and the only known candidate for low-z Lyman continuum emission. To aid in the interpretation, we perform a detailed ultraviolet and optical multiwavelength analysis and model the stellar population, dust distribution, ionizing photon budget, and star-cluster population. We use archival X-ray observations to further constrain properties of the starburst and estimate the neutral hydrogen column density. The Lyα morphology is found to be largely symmetric around a single young star-forming knot and is strongly decoupled from other wavelengths. From general surface photometry, only very slight correlation is found between Lyα and Hα, E(B - V), and the age of the stellar population. Only around the central Lyα bright cluster do we find the Lyα/Hα ratio at values predicted by the recombination theory. The total Lyα escape fraction is found to be just 3 per cent. We compute that ~90 per cent of the Lyα photons that escape do so after undergoing multiple resonance scattering events, masking their point of origin. This leads to a largely symmetric distribution and, by increasing the distance that photons must travel to escape, decreases the escape probability significantly. While dust must ultimately be responsible for the destruction of Lyα, it plays a little role in governing the observed morphology, which is regulated more by interstellar medium kinematics and geometry. We find tentative evidence for local Lyα equivalent width in the immediate vicinity of star clusters being a function of cluster age, consistent with hydrodynamic studies. We estimate the intrinsic production

  1. New results on strong-interaction effects in antiprotonic hydrogen

    CERN Document Server

    Gotta, D; Augsburger, M A; Borchert, G L; Castelli, C M; Chatellard, D; El-Khoury, P; Egger, J P; Gorke, H; Hauser, P R; Indelicato, P J; Kirch, K; Lenz, S; Nelms, N; Rashid, K; Schult, O W B; Siems, T; Simons, L M

    1999-01-01

    Lyman and Balmer transitions of antiprotonic hydrogen and deuterium have been measured at the low-energy antiproton ring LEAR at CERN in order to determine the strong interaction effects. The X-rays were detected using charge-coupled devices (CCDs) and a reflection type crystal spectrometer. The results of the measurements support the meson-exchange models describing the medium and long range part of the nucleon-antinucleon interaction. (33 refs).

  2. New results on strong-interaction effects in antiprotonic hydrogen

    International Nuclear Information System (INIS)

    Anagnostopoulos, D. F.; Augsburger, M.; Borchert, G.; Castelli, C.; Chatellard, D.; El-Khoury, P.; Egger, J.-P.; Gorke, H.; Gotta, D.; Hauser, P.; Indelicato, P.; Kirch, K.; Lenz, S.; Nelms, N.; Rashid, K.; Schult, O. W. B.; Siems, Th.; Simons, L. M.

    1999-01-01

    Lyman and Balmer transitions of antiprotonic hydrogen and deuterium have been measured at the Low-Energy Antiproton Ring LEAR at CERN in order to determine the strong interaction effects. The X-rays were detected using Charge-Coupled Devices (CCDs) and a reflection type crystal spectrometer. The results of the measurements support the meson-exchange models describing the medium and long range part of the nucleon-antinucleon interaction

  3. Discovery of Ubiquitous Fast-Propagating Intensity Disturbances by the Chromospheric Lyman Alpha Spectropolarimeter (CLASP)

    Science.gov (United States)

    Kubo, M.; Katsukawa, Y.; Suematsu, Y.; Kano, R.; Bando, T.; Narukage, N.; Ishikawa, R.; Hara, H.; Giono, G.; Tsuneta, S.; Ishikawa, S.; Shimizu, T.; Sakao, T.; Winebarger, A.; Kobayashi, K.; Cirtain, J.; Champey, P.; Auchère, F.; Trujillo Bueno, J.; Asensio Ramos, A.; Štěpán, J.; Belluzzi, L.; Manso Sainz, R.; De Pontieu, B.; Ichimoto, K.; Carlsson, M.; Casini, R.; Goto, M.

    2016-12-01

    High-cadence observations by the slit-jaw (SJ) optics system of the sounding rocket experiment known as the Chromospheric Lyman Alpha Spectropolarimeter (CLASP) reveal ubiquitous intensity disturbances that recurrently propagate in either the chromosphere or the transition region or both at a speed much higher than the speed of sound. The CLASP/SJ instrument provides a time series of two-dimensional images taken with broadband filters centered on the Lyα line at a 0.6 s cadence. The multiple fast-propagating intensity disturbances appear in the quiet Sun and in an active region, and they are clearly detected in at least 20 areas in a field of view of 527″ × 527″ during the 5 minute observing time. The apparent speeds of the intensity disturbances range from 150 to 350 km s-1, and they are comparable to the local Alfvén speed in the transition region. The intensity disturbances tend to propagate along bright elongated structures away from areas with strong photospheric magnetic fields. This suggests that the observed fast-propagating intensity disturbances are related to the magnetic canopy structures. The maximum distance traveled by the intensity disturbances is about 10″, and the widths are a few arcseconds, which are almost determined by a pixel size of 1.″03. The timescale of each intensity pulse is shorter than 30 s. One possible explanation for the fast-propagating intensity disturbances observed by CLASP is magnetohydrodynamic fast-mode waves.

  4. Constraining the Intergalactic and Circumgalactic Media with Lyman-Alpha Absorption

    Science.gov (United States)

    Sorini, Daniele; Onorbe, Jose; Hennawi, Joseph F.; Lukic, Zarija

    2018-01-01

    Lyman-alpha (Ly-a) absorption features detected in quasar spectra in the redshift range 02Mpc, the simulations asymptotically match the observations, because the ΛCDM model successfully describes the ambient IGM. This represents a critical advantage of studying the mean absorption profile. However, significant differences between the simulations, and between simulations and observations are present on scales 20kpc-2Mpc, illustrating the challenges of accurately modeling and resolving galaxy formation physics. It is noteworthy that these differences are observed as far out as ~2Mpc, indicating that the `sphere-of-influence' of galaxies could extend to approximately ~20 times the halo virial radius (~100kpc). Current observations are very precise on these scales and can thus strongly discriminate between different galaxy formation models. I demonstrate that the Ly-a absorption profile is primarily sensitive to the underlying temperature-density relationship of diffuse gas around galaxies, and argue that it thus provides a fundamental test of galaxy formation models. With near-future high-precision observations of Ly-a absorption, the tools developed in my thesis set the stage for even stronger constraints on models of galaxy formation and cosmology.

  5. SPECTROSCOPIC CONFIRMATION OF FAINT LYMAN BREAK GALAXIES NEAR REDSHIFT FIVE IN THE HUBBLE ULTRA DEEP FIELD

    International Nuclear Information System (INIS)

    Rhoads, James E.; Malhotra, Sangeeta; Cohen, Seth; Grogin, Norman; Hathi, Nimish; Ryan, Russell; Straughn, Amber; Windhorst, Rogier A.; Pirzkal, Norbert; Xu Chun; Koekemoer, Anton; Panagia, Nino; Dickinson, Mark; Ferreras, Ignacio; Gronwall, Caryl; Kuemmel, Martin; Walsh, Jeremy; Meurer, Gerhardt; Pasquali, Anna; Yan, H.-J.

    2009-01-01

    We present the faintest spectroscopically confirmed sample of z ∼ 5 Lyman break galaxies (LBGs) to date. The sample is based on slitless grism spectra of the Hubble Ultra Deep Field region from the Grism ACS Program for Extragalactic Science (GRAPES) and Probing Evolution and Reionization Spectroscopically (PEARS) projects, using the G800L grism on the Hubble Space Telescope Advanced Camera for Surveys. We report here confirmations of 39 galaxies, preselected as candidate LBGs using photometric selection criteria. We compare a 'traditional' V-dropout selection, based on the work of Giavalisco et al., to a more liberal one (with V - i > 0.9), and find that the traditional criteria are about 64% complete and 81% reliable. We also study the Lyα emission properties of our sample. We find that Lyα emission is detected in ∼1/4 of the sample, and that the liberal V-dropout color selection includes ∼55% of previously published line-selected Lyα sources. Finally, we examine our stacked two-dimensional spectra. We demonstrate that strong, spatially extended (∼1'') Lyα emission is not a generic property of these LBGs, but that a modest extension of the Lyα photosphere (compared to the starlight) may be present in those galaxies with prominent Lyα emission.

  6. Development of Flight Slit-Jaw Optics for Chromospheric Lyman-Alpha SpectroPolarimeter

    Science.gov (United States)

    Kubo, Masahito; Suematsu, Yoshinori; Kano, Ryohei; Bando, Takamasa; Hara, Hirohisa; Narukage, Noriyuki; Katsukawa, Yukio; Ishikawa, Ryoko; Ishikawa, Shin-nosuke; Kobiki, Toshihiko; hide

    2015-01-01

    In sounding rocket experiment CLASP, I have placed a slit a mirror-finished around the focal point of the telescope. The light reflected by the mirror surface surrounding the slit is then imaged in Slit-jaw optical system, to obtain the alpha-ray Lyman secondary image. This image, not only to use the real-time image in rocket flight rocket oriented direction selection, and also used as a scientific data showing the spatial structure of the Lyman alpha emission line intensity distribution and solar chromosphere around the observation area of the polarimetric spectroscope. Slit-jaw optical system is a two off-axis mirror unit part including a parabolic mirror and folding mirror, Lyman alpha transmission filter, the optical system magnification 1x consisting camera. The camera is supplied from the United States, and the other was carried out fabrication and testing in all the Japanese side. Slit-jaw optical system, it is difficult to access the structure, it is necessary to install the low place clearance. Therefore, influence the optical performance, the fine adjustment is necessary optical elements are collectively in the form of the mirror unit. On the other hand, due to the alignment of the solar sensor in the US launch site, must be removed once the Lyman alpha transmission filter holder including a filter has a different part from the mirror unit. In order to make the structure simple, stray light measures Aru to concentrate around Lyman alpha transmission filter. To overcome the difficulties of performing optical alignment in Lyman alpha wavelength absorbed by the atmosphere, it was planned following four steps in order to reduce standing time alignment me. 1: is measured in advance refractive index at Lyman alpha wavelength of Lyman alpha transmission filter (121.567nm), to prepare a visible light Firuwo having the same optical path length in the visible light (630nm). 2: The mirror structure CLASP before mounting unit standing, dummy slit and camera standing

  7. Magnified Weak Lensing Cross Correlation Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ulmer, Melville P., Clowe, Douglas I.

    2010-11-30

    nights on 4-m class telescopes, which gives concrete evidence of strong community support for this project. The WLT technique is based on the dependence of the gravitational shear signal on the angular diameter distances between the observer, the lens, and the lensed galaxy to measure cosmological parameters. By taking the ratio of measured shears of galaxies with different redshifts around the same lens, one obtains a measurement of the ratios of the angular diameter distances involved. Making these observations over a large range of lenses and background galaxy redshifts will measure the history of the expansion rate of the universe. Because this is a purely geometric measurement, it is insensitive to any form of evolution of objects or the necessity to understand the physics in the early universe. Thus, WLT was identified by the Dark Energy Task Force as perhaps the best method to measure the evolution of DE. To date, however, the conjecture of the DETF has not been experimentally verified, but will be by the proposed project. The primary reason for the lack of tomography measurements is that one must have an exceptional data-set to attempt the measurement. One needs both extremely good seeing (or space observations) in order to minimize the point spread function smearing corrections on weak lensing shear measurements and deep, multi-color data, from B to z, to measure reliable photometric redshifts of the background galaxies being lensed (which are typically too faint to obtain spectroscopic redshifts). Because the entire process from multi-drizzling the HST images, and then creating shear maps, to gathering the necessary ground based observations, to generating photo-zs and then carrying out the tomography is a complicated task, until the creation of our team, nobody has taken the time to connect all the levels of expertise necessary to carry out this project based on HST archival data. Our data are being used in 2 Ph.D. theses. Kellen Murphy, at Ohio University, is

  8. Impact of Lyman alpha pressure on metal-poor dwarf galaxies

    Science.gov (United States)

    Kimm, Taysun; Haehnelt, Martin; Blaizot, Jérémy; Katz, Harley; Michel-Dansac, Léo; Garel, Thibault; Rosdahl, Joakim; Teyssier, Romain

    2018-04-01

    Understanding the origin of strong galactic outflows and the suppression of star formation in dwarf galaxies is a key problem in galaxy formation. Using a set of radiation-hydrodynamic simulations of an isolated dwarf galaxy embedded in a 1010 M⊙ halo, we show that the momentum transferred from resonantly scattered Lyman-α (Lyα) photons is an important source of stellar feedback which can shape the evolution of galaxies. We find that Lyα feedback suppresses star formation by a factor of two in metal-poor galaxies by regulating the dynamics of star-forming clouds before the onset of supernova explosions (SNe). This is possible because each Lyα photon resonantly scatters and imparts ˜10-300 times greater momentum than in the single scattering limit. Consequently, the number of star clusters predicted in the simulations is reduced by a factor of ˜5, compared to the model without the early feedback. More importantly, we find that galactic outflows become weaker in the presence of strong Lyα radiation feedback, as star formation and associated SNe become less bursty. We also examine a model in which radiation field is arbitrarily enhanced by a factor of up to 10, and reach the same conclusion. The typical mass-loading factors in our metal-poor dwarf system are estimated to be ˜5-10 near the mid-plane, while it is reduced to ˜1 at larger radii. Finally, we find that the escape of ionizing radiation and hence the reionization history of the Universe is unlikely to be strongly affected by Lyα feedback.

  9. Gravitational lensing of gravitational waves: a statistical perspective

    Science.gov (United States)

    Li, Shun-Sheng; Mao, Shude; Zhao, Yuetong; Lu, Youjun

    2018-05-01

    In this paper, we study the strong gravitational lensing of gravitational waves (GWs) from a statistical perspective, with particular focus on the high frequency GWs from stellar binary black hole coalescences. These are most promising targets for ground-based detectors such as Advanced Laser Interferometer Gravitational Wave Observatory (aLIGO) and the proposed Einstein Telescope (ET) and can be safely treated under the geometrical optics limit for GW propagation. We perform a thorough calculation of the lensing rate, by taking account of effects caused by the ellipticity of lensing galaxies, lens environments, and magnification bias. We find that in certain GW source rate scenarios, we should be able to observe strongly lensed GW events once per year (˜1 yr-1) in the aLIGO survey at its design sensitivity; for the proposed ET survey, the rate could be as high as ˜80 yr-1. These results depend on the estimate of GW source abundance, and hence can be correspondingly modified with an improvement in our understanding of the merger rate of stellar binary black holes. We also compute the fraction of four-image lens systems in each survey, predicting it to be ˜30 per cent for the aLIGO survey and ˜6 per cent for the ET survey. Finally, we evaluate the possibility of missing some images due to the finite survey duration, by presenting the probability distribution of lensing time delays. We predict that this selection bias will be insignificant in future GW surveys, as most of the lens systems ({˜ } 90{per cent}) will have time delays less than ˜1 month, which will be far shorter than survey durations.

  10. Discovery of four gravitational lensing systems by clusters in the SDSS DR6

    International Nuclear Information System (INIS)

    Wen Zhonglue; Han Jinlin; Xu Xiangyang; Jiang Yunying; Guo Zhiqing; Wang Pengfei; Liu Fengshan

    2009-01-01

    We report the discovery of 4 strong gravitational lensing systems by visual inspections of the Sloan Digital Sky Survey images of galaxy clusters in Data Release 6 (SDSS DR6). Two of the four systems show Einstein rings while the others show tangential giant arcs. These arcs or rings have large angular separations (> 8) from the bright central galaxies and show bluer color compared with the red cluster galaxies. In addition, we found 5 probable and 4 possible lenses by galaxy clusters. (letters)

  11. Continuous emission from the gaseous nebula beyond the Lyman limit

    International Nuclear Information System (INIS)

    Bolgova, G.T.; Khromov, G.S.

    1975-01-01

    Models of spherically-symmetric isothermic hydrogen nebula with an exciting star in the centre are considered. Spectra and energies of diffuse radiation of nebula and of direct radiation of its kernel are calculated in the Lyman continuum for the external boundary of the object. The spectrum of the diffuse radiation is shown to be to a great extent invariant in relation to all parameters of models except for Tsub(e). The total loss in energy of Lsub(c)-radiation of kernel through the external border of the ionized nebula, amounts to 20-30% in the average even at a considerable optical thickness of the object tausub(0). The greater part of this energy is transferred via direct ionizing radiation, though the relative contribution of the diffuse Lsub(c)-radiation of nebula reaches 30% at low temperatures of the exciting star and at large tausub(0). The results of this work may be applied to calculating the energy balance of the star-nebula system, the heating of dust particles and ionization of the neighbouring interstellar medium, and also for determining the conditions of observation of the far ultra-violet radiation of similar objects

  12. The Lyman-alpha signature of the first galaxies

    Science.gov (United States)

    Smith, Aaron

    2018-01-01

    Radiation from the first stars and galaxies initiated the dramatic phase transition marking an end to the cosmic dark ages. The emission and absorption signatures from the Lyman-alpha (Lyα) transition of neutral hydrogen have been indispensable in extending the observational frontier for high-redshift galaxies into the epoch of reionization. Lyα radiative transfer provides clues about the processes leading to Lyα escape from individual galaxies and the subsequent transmission through the intergalactic medium. Cosmological simulations incorporating Lyα radiative transfer enhance our understanding of fundamental physics by supplying the inferred spectra and feedback on the gas. In this talk, I will discuss the dynamical impact of Lyα radiation pressure on galaxy formation throughout cosmic reionization with the first fully coupled Lyα radiation-hydrodynamics simulations. Based on a suite of spherically symmetric models and high-resolution ab initio cosmological simulations we find that Lyα radiation pressure is dynamically important during the assembly of direct collapse black holes (DCBHs), which may be the seeds of the first supermassive black holes in the universe. Finally, I will discuss recent advances in Lyα modeling based on current state-of-the-art simulations and observational insights.

  13. New case of gravitational lensing

    Energy Technology Data Exchange (ETDEWEB)

    Surdej, J.; Swings, J.-P.; Magain, P.; Borgeest, U.; Kayser, R.; Refsdal, S.; Courvoisier, T.J.-L.; Kellermann, K.I.; Kuehr, H.

    1987-10-22

    The authors report a brief description of a gravitational lens system UM673 = Q0142 - 100 = PHL3703. It consists of two images, A and B, separated by 2.2 arc s at a redshift zsub(q) = 2.719. The lensing galaxy has also been found. It lies very near the line connecting the two QSO (quasi-stellar objects) images, approx. 0.8 arc s from the fainter one. Application of gravitational optometry to this system leads to a value Msub(o) or approx. = 2.4 x 10/sup 11/ M solar masses for the mass of the lensing galaxy and to ..delta..t approx. 7 weeks for the most likely travel-time difference between the two light paths to the QSO.

  14. A system of catoptric lenses

    International Nuclear Information System (INIS)

    McFarland, P.J.; Rambauske, W.R.

    1973-01-01

    Description is given of a system of catoptric lenses for combining energies provided by a certain number of sources, e.g. optical energies provided by a certain number of lasers. This system comprises sets of mirrors the reflecting surfaces of which have their focuses spaced from a common axis. The mirrors of all these sets are arranged on a common frame, which makes aperture-locking impossible. This can be applied to thermonuclear fusion [fr

  15. Gravitational lensing in plasmic medium

    Energy Technology Data Exchange (ETDEWEB)

    Bisnovatyi-Kogan, G. S., E-mail: gkogan@iki.rssi.ru; Tsupko, O. Yu., E-mail: tsupko@iki.rssi.ru [Russian Academy of Sciences, Space Research Institute (Russian Federation)

    2015-07-15

    The influence of plasma on different effects of gravitational lensing is reviewed. Using the Hamiltonian approach for geometrical optics in a medium in the presence of gravity, an exact formula for the photon deflection angle by a black hole (or another body with a Schwarzschild metric) embedded in plasma with a spherically symmetric density distribution is derived. The deflection angle in this case is determined by the mutual combination of different factors: gravity, dispersion, and refraction. While the effects of deflection by the gravity in vacuum and the refractive deflection in a nonhomogeneous medium are well known, the new effect is that, in the case of a homogeneous plasma, in the absence of refractive deflection, the gravitational deflection differs from the vacuum deflection and depends on the photon frequency. In the presence of a plasma nonhomogeneity, the chromatic refractive deflection also occurs, so the presence of plasma always makes gravitational lensing chromatic. In particular, the presence of plasma leads to different angular positions of the same image if it is observed at different wavelengths. It is discussed in detail how to apply the presented formulas for the calculation of the deflection angle in different situations. Gravitational lensing in plasma beyond the weak deflection approximation is also considered.

  16. DARK MATTER SUBSTRUCTURE DETECTION USING SPATIALLY RESOLVED SPECTROSCOPY OF LENSED DUSTY GALAXIES

    International Nuclear Information System (INIS)

    Hezaveh, Yashar; Holder, Gilbert; Dalal, Neal; Kuhlen, Michael; Marrone, Daniel; Murray, Norman; Vieira, Joaquin

    2013-01-01

    We investigate how strong lensing of dusty, star-forming galaxies (DSFGs) by foreground galaxies can be used as a probe of dark matter halo substructure. We find that spatially resolved spectroscopy of lensed sources allows dramatic improvements to measurements of lens parameters. In particular, we find that modeling of the full, three-dimensional (angular position and radial velocity) data can significantly facilitate substructure detection, increasing the sensitivity of observables to lower mass subhalos. We carry out simulations of lensed dusty sources observed by early ALMA (Cycle 1) and use a Fisher matrix analysis to study the parameter degeneracies and mass detection limits of this method. We find that even with conservative assumptions, it is possible to detect galactic dark matter subhalos of ∼10 8 M ☉ with high significance in most lensed DSFGs. Specifically, we find that in typical DSFG lenses, there is a ∼55% probability of detecting a substructure with M > 10 8 M ☉ with more than 5σ detection significance in each lens, if the abundance of substructure is consistent with previous lensing results. The full ALMA array, with its significantly enhanced sensitivity and resolution, should improve these estimates considerably. Given the sample of ∼100 lenses provided by surveys such as the South Pole Telescope, our understanding of dark matter substructure in typical galaxy halos is poised to improve dramatically over the next few years.

  17. DARK MATTER SUBSTRUCTURE DETECTION USING SPATIALLY RESOLVED SPECTROSCOPY OF LENSED DUSTY GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Hezaveh, Yashar; Holder, Gilbert [Department of Physics, McGill University, 3600 Rue University, Montreal, Quebec H3A 2T8 (Canada); Dalal, Neal [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Kuhlen, Michael [Theoretical Astrophysics Center, University of California, Berkeley, CA 94720 (United States); Marrone, Daniel [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Murray, Norman [CITA, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Vieira, Joaquin [California Institute of Technology, 1200 East California Blvd, MC 249-17, Pasadena, CA 91125 (United States)

    2013-04-10

    We investigate how strong lensing of dusty, star-forming galaxies (DSFGs) by foreground galaxies can be used as a probe of dark matter halo substructure. We find that spatially resolved spectroscopy of lensed sources allows dramatic improvements to measurements of lens parameters. In particular, we find that modeling of the full, three-dimensional (angular position and radial velocity) data can significantly facilitate substructure detection, increasing the sensitivity of observables to lower mass subhalos. We carry out simulations of lensed dusty sources observed by early ALMA (Cycle 1) and use a Fisher matrix analysis to study the parameter degeneracies and mass detection limits of this method. We find that even with conservative assumptions, it is possible to detect galactic dark matter subhalos of {approx}10{sup 8} M{sub Sun} with high significance in most lensed DSFGs. Specifically, we find that in typical DSFG lenses, there is a {approx}55% probability of detecting a substructure with M > 10{sup 8} M{sub Sun} with more than 5{sigma} detection significance in each lens, if the abundance of substructure is consistent with previous lensing results. The full ALMA array, with its significantly enhanced sensitivity and resolution, should improve these estimates considerably. Given the sample of {approx}100 lenses provided by surveys such as the South Pole Telescope, our understanding of dark matter substructure in typical galaxy halos is poised to improve dramatically over the next few years.

  18. 30 CFR 18.30 - Windows and lenses.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Windows and lenses. 18.30 Section 18.30 Mineral... § 18.30 Windows and lenses. (a) MSHA may waive testing of materials for windows or lenses except headlight lenses. When tested, material for windows or lenses shall meet the test requirements prescribed in...

  19. Planck 2015 results. XV. Gravitational lensing

    CERN Document Server

    Ade, P.A.R.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Bartlett, J.G.; Bartolo, N.; Basak, S.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bock, J.J.; Bonaldi, A.; Bonavera, L.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Boulanger, F.; Bucher, M.; Burigana, C.; Butler, R.C.; Calabrese, E.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, H.C.; Christensen, P.R.; Church, S.; Clements, D.L.; Colombi, S.; Colombo, L.P.L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B.P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; Davis, R.J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Désert, F.-X.; Diego, J.M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T.A.; Eriksen, H.K.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A.A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K.M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J.E.; Hansen, F.K.; Hanson, D.; Harrison, D.L.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huffenberger, K.M.; Hurier, G.; Jaffe, A.H.; Jaffe, T.R.; Jones, W.C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T.S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C.R.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Lewis, A.; Liguori, M.; Lilje, P.B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P.M.; Macías-Pérez, J.F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P.G.; Martínez-González, E.; Masi, S.; Matarrese, S.; McGehee, P.; Meinhold, P.R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J.A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Nørgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C.A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Popa, L.; Pratt, G.W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J.P.; Reach, W.T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; Rowan-Robinson, M.; Rubiño-Martín, J.A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Savini, G.; Scott, D.; Seiffert, M.D.; Shellard, E.P.S.; Spencer, L.D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J.A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L.A.; Wandelt, B.D.; Wehus, I.K.; White, M.; Yvon, D.; Zacchei, A.

    2016-01-01

    We present the most significant measurement of the cosmic microwave background (CMB) lensing potential to date (at a level of 40 sigma), using temperature and polarization data from the Planck 2015 full-mission release. Using a polarization-only estimator we detect lensing at a significance of 5 sigma. We cross-check the accuracy of our measurement using the wide frequency coverage and complementarity of the temperature and polarization measurements. Public products based on this measurement include an estimate of the lensing potential over approximately 70% of the sky, an estimate of the lensing potential power spectrum in bandpowers for the multipole range 40lensing potential power spectrum and that found in the best-fitting LCDM model based on the Planck temperature and polarization power spectra. Using the lensing likelihood alone we obtain a percent-level measurement of ...

  20. Anisotropic Galaxy-Galaxy Lensing in the Illustris-1 Simulation

    Science.gov (United States)

    Brainerd, Tereasa G.

    2017-06-01

    In Cold Dark Matter universes, the dark matter halos of galaxies are expected to be triaxial, leading to a surface mass density that is not circularly symmetric. In principle, this "flattening" of the dark matter halos of galaxies should be observable as an anisotropy in the weak galaxy-galaxy lensing signal. The degree to which the weak lensing signal is observed to be anisotropic, however, will depend strongly on the degree to which mass (i.e., the dark matter) is aligned with light in the lensing galaxies. That is, the anisotropy will be maximized when the major axis of the projected mass distribution is well aligned with the projected light distribution of the lens galaxies. Observational studies of anisotropic galaxy-galaxy lensing have found an anisotropic weak lensing signal around massive, red galaxies. Detecting the signal around blue, disky galaxies has, however, been more elusive. A possible explanation for this is that mass and light are well aligned within red galaxies and poorly aligned within blue galaxies (an explanation that is supported by studies of the locations of satellites of large, relatively isolated galaxies). Here we compute the weak lensing signal of isolated central galaxies in the Illustris-1 simulation. We compute the anisotropy of the weak lensing signal using two definitions of the geometry: [1] the major axis of the projected dark matter mass distribution and [2] the major axis of the projected stellar mass. On projected scales less than 15% of the virial radius, an anisotropy of order 10% is found for both definitions of the geometry. On larger scales, the anisotropy computed relative to the major axis of the projected light distribution is less than the anisotropy computed relative to the major axis of the projected dark matter. On projected scales of order the virial radius, the anisotropy obtained when using the major axis of the light is an order of magnitude less than the anisotropy obtained when using the major axis of the

  1. Instrumental systematics and weak gravitational lensing

    International Nuclear Information System (INIS)

    Mandelbaum, R.

    2015-01-01

    We present a pedagogical review of the weak gravitational lensing measurement process and its connection to major scientific questions such as dark matter and dark energy. Then we describe common ways of parametrizing systematic errors and understanding how they affect weak lensing measurements. Finally, we discuss several instrumental systematics and how they fit into this context, and conclude with some future perspective on how progress can be made in understanding the impact of instrumental systematics on weak lensing measurements

  2. Factors influencing bacterial adhesion to contact lenses

    OpenAIRE

    Dutta, Debarun; Cole, Nerida; Willcox, Mark

    2012-01-01

    The process of any contact lens related keratitis generally starts with the adhesion of opportunistic pathogens to contact lens surface. This article focuses on identifying the factors which have been reported to affect bacterial adhesion to contact lenses. Adhesion to lenses differs between various genera/species/strains of bacteria. Pseudomonas aeruginosa, which is the predominant causative organism, adheres in the highest numbers to both hydrogel and silicone hydrogel lenses in vitro. The ...

  3. A Lyman Break Galaxy Candidate at z ~ 9

    Science.gov (United States)

    Henry, Alaina L.; Malkan, Matthew A.; Colbert, James W.; Siana, Brian; Teplitz, Harry I.; McCarthy, Patrick

    2008-06-01

    We report the discovery of a z ~ 9 Lyman break galaxy candidate, selected from the NICMOS Parallel Imaging Survey as a J-dropout with J110 - H160 = 1.7. Spitzer/IRAC photometry reveals that the galaxy has a blue H160 - 3.6 μm color and a spectral break between 3.6 and 4.5 μm. We interpret this break as the Balmer break and derive a best-fit photometric redshift of z ~ 9. We use Monte Carlo simulations to test the significance of this photometric redshift, and we show that there is a 96% probability of z >= 7. We estimate that the lower limit to the comoving number density of such galaxies at z ~ 9 is phi > 3.8 × 10-6 Mpc-3. If the high redshift of this galaxy is confirmed, this will indicate that the luminous end of the rest-frame UV luminosity function has not evolved substantially from z ~ 9 to z ~ 3. Still, some small degeneracy remains between this z ~ 9 model and models at z ~ 2-3 deep optical imaging (reaching IAB ~ 29) can rule out the lower z models. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory (JPL), California Institute of Technology, under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. This work is also based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with proposals 9484, 9865, 10226, and 10899.

  4. Lyman Break Galaxies At z 2 In The GOODS Fields

    Science.gov (United States)

    Haberzettl, Lutz; Williger, G.; Lehnert, M.; Nesvadba, N.

    2009-12-01

    Lyman Break Galaxies (LBGs) have been the benchmarks against which other samples of high redshift galaxies have been compared for the last 2 decades. They are unique in that no other selection mechanism allows us to study galaxies selected in a consistent manner over the span of redshifts from z=0 to 7. An important remaining gap is the redshift range z ˜ 1.5-2.5, which includes near UV (NUV)-band drop-outs. We present first results of a search for LBGs at these redshifts using very sensitive multi-frequency data from the far UV to mid-IR of the GOODS CDF-S and HDF-N. We modelled colors of star-forming galaxies, and found only a small overlap with the BM/BX selection method (Adelberger et al. 2004, ApJ, 607, 226). We developed new color selection criteria using GALEX NUV and optical photometry to identify high star formation galaxies, including NUV-dropouts for 2.0methods, we identified a sample of ? z˜ 2 LBG candidates in both the GOODS CDF-S and the HDF-N. A first analysis of the mean SED of our LBG candidate sample shows results consistent with red LBGs at z ˜ 1, indicating massive galaxies with high star formation rates. Nearly 10% of our selected LBG candidates have mid-IR (IRAC+MIPS) colors comparable both to z ˜ 3 IR-luminous LBGs, which are believed to be dusty, vigorously star-forming massive progenitors of modern ellipticals.

  5. Modeling fine-scale geological heterogeneity-examples of sand lenses in tills

    DEFF Research Database (Denmark)

    Kessler, Timo Christian; Comunian, Alessandro; Oriani, Fabio

    2013-01-01

    that hamper subsequent simulation. Transition probability (TP) and multiple-point statistics (MPS) were employed to simulate sand lens heterogeneity. We used one cross-section to parameterize the spatial correlation and a second, parallel section as a reference: it allowed testing the quality......Sand lenses at various spatial scales are recognized to add heterogeneity to glacial sediments. They have high hydraulic conductivities relative to the surrounding till matrix and may affect the advective transport of water and contaminants in clayey till settings. Sand lenses were investigated...... on till outcrops producing binary images of geological cross-sections capturing the size, shape and distribution of individual features. Sand lenses occur as elongated, anisotropic geobodies that vary in size and extent. Besides, sand lenses show strong non-stationary patterns on section images...

  6. Are the brightest Lyman Alpha Emitters at z=5.7 primeval galaxies?

    Science.gov (United States)

    Lidman, Christopher; Jones, Heath; Meisenheimer, Klaus; Pompei, Emanuela; Tapken, Christian; Vanzi, Leonardo; Westra, Eduard

    2008-03-01

    Wide-field, narrow-band surveys have proven to be effective at finding very high redshift galaxies that emit brightly in the Lyman alpha line, the so-called Lyman alpha emitters (LAEs). It was through this technique that the most distant spectroscopically confirmed galaxy, a galaxy at z=6.96, was discovered. Considerable effort is currently being spent on discovering these galaxies at ever higher redshifts by extending this technique into the near-IR. In contrast to this effort, there has been relatively little work on understanding these galaxies. In particular, how do LAEs relate to other high redshift galaxies, such as the galaxies discovered through broad band drop out techniques, and, perhaps, more importantly, what role do LAEs play in re-ionising the universe. We recently discovered two extremely luminous LAEs at z=5.7. These LAEs are among the brightest LAEs ever discovered at this redshift. In a recent paper by Mao et al. the brightest LAEs are associated to the most massive halos. We propose to use the IRAC 3.6 micron imager on Spitzer to measure the rest-frame optical flux of the these LAEs. With additional data from the near-IR (rest-frame UV) and very deep optical spectra around the Lyman alpha line, we propose to make a detailed study of the spectral energy distribution from the Lyman alpha line to the rest frame optical of these exceptional LAEs. These data will enable us to estimate the age and mass of the stellar burst that produces the Lyman alpha line, to estimate the contribution from an older stellar population, if any, and to estimate the fraction of Lyman continuum photons that can escape the galaxy and are thus available to reionise the universe.

  7. ALMA observations of lensed Herschel sources: testing the dark matter halo paradigm

    Science.gov (United States)

    Amvrosiadis, A.; Eales, S. A.; Negrello, M.; Marchetti, L.; Smith, M. W. L.; Bourne, N.; Clements, D. L.; De Zotti, G.; Dunne, L.; Dye, S.; Furlanetto, C.; Ivison, R. J.; Maddox, S. J.; Valiante, E.; Baes, M.; Baker, A. J.; Cooray, A.; Crawford, S. M.; Frayer, D.; Harris, A.; Michałowski, M. J.; Nayyeri, H.; Oliver, S.; Riechers, D. A.; Serjeant, S.; Vaccari, M.

    2018-04-01

    With the advent of wide-area submillimetre surveys, a large number of high-redshift gravitationally lensed dusty star-forming galaxies have been revealed. Because of the simplicity of the selection criteria for candidate lensed sources in such surveys, identified as those with S500 μm > 100 mJy, uncertainties associated with the modelling of the selection function are expunged. The combination of these attributes makes submillimetre surveys ideal for the study of strong lens statistics. We carried out a pilot study of the lensing statistics of submillimetre-selected sources by making observations with the Atacama Large Millimeter Array (ALMA) of a sample of strongly lensed sources selected from surveys carried out with the Herschel Space Observatory. We attempted to reproduce the distribution of image separations for the lensed sources using a halo mass function taken from a numerical simulation that contains both dark matter and baryons. We used three different density distributions, one based on analytical fits to the haloes formed in the EAGLE simulation and two density distributions [Singular Isothermal Sphere (SIS) and SISSA] that have been used before in lensing studies. We found that we could reproduce the observed distribution with all three density distributions, as long as we imposed an upper mass transition of ˜1013 M⊙ for the SIS and SISSA models, above which we assumed that the density distribution could be represented by a Navarro-Frenk-White profile. We show that we would need a sample of ˜500 lensed sources to distinguish between the density distributions, which is practical given the predicted number of lensed sources in the Herschel surveys.

  8. Experimental studies of stable confined electron clouds using Gabor lenses

    CERN Document Server

    Meusel, O.; Glaeser, B.; Schulte, K.

    2013-04-22

    Based on the idea of D. Gabor [1] space charge lenses are under investigation to be a powerful focussing device for intense ion beams. A stable confined electron column is used to provide strong radially symmetric electrostatic focussing, e.g. for positively charged ion beams. The advantages of Gabor lenses are a mass independent focussing strength, space charge compensation of the ion beam and reduced magnetic or electric fields compared to conventional focussing devices. Collective phenomena of the electron cloud result in aberrations and emittance growth of the ion beam. The knowledge of the behaviour of the electron cloud prevents a decrease of the beam brilliance. Numerical models developed to describe the electron confinement and dynamics within a Gabor lens help to understand the interaction of the ion beam with the electron column and show the causes of non-neutral plasma instabilities. The diagnosis of the electron cloud properties helps to evaluate the numerical models and to investigate the influen...

  9. Precision cosmology from future lensed gravitational wave and electromagnetic signals.

    Science.gov (United States)

    Liao, Kai; Fan, Xi-Long; Ding, Xuheng; Biesiada, Marek; Zhu, Zong-Hong

    2017-10-27

    The standard siren approach of gravitational wave cosmology appeals to the direct luminosity distance estimation through the waveform signals from inspiralling double compact binaries, especially those with electromagnetic counterparts providing redshifts. It is limited by the calibration uncertainties in strain amplitude and relies on the fine details of the waveform. The Einstein telescope is expected to produce 10 4 -10 5 gravitational wave detections per year, 50-100 of which will be lensed. Here, we report a waveform-independent strategy to achieve precise cosmography by combining the accurately measured time delays from strongly lensed gravitational wave signals with the images and redshifts observed in the electromagnetic domain. We demonstrate that just 10 such systems can provide a Hubble constant uncertainty of 0.68% for a flat lambda cold dark matter universe in the era of third-generation ground-based detectors.

  10. Photometry of High-Redshift Gravitationally Lensed Type Ia Supernovae

    Science.gov (United States)

    Haynie, Annastasia

    2018-01-01

    Out of more than 1100 well-identified Type Ia Supernovae, only roughly 10 of them are at z> 1.5. High redshift supernovae are hard to detect but this is made easier by taking advantage of the effects of gravitational lensing, which magnifies objects in the background field of massive galaxy clusters. Supernova Nebra (z= ~1.8), among others, was discovered during observations taken as part of the RELICS survey, which focused on fields of view that experience strong gravitational lensing effects. SN Nebra, which sits behind galaxy cluster Abell 1763, is magnified and therefore appears closer and easier to see than with HST alone. Studying high-redshift supernovae like SN Nebra is an important step towards creating cosmological models that accurately describe the behavior of dark energy in the early Universe. Recent efforts have been focused on improving photometry and the building and fitting of preliminary light curves.

  11. The Scales of Gravitational Lensing

    Directory of Open Access Journals (Sweden)

    Francesco De Paolis

    2016-03-01

    Full Text Available After exactly a century since the formulation of the general theory of relativity, the phenomenon of gravitational lensing is still an extremely powerful method for investigating in astrophysics and cosmology. Indeed, it is adopted to study the distribution of the stellar component in the Milky Way, to study dark matter and dark energy on very large scales and even to discover exoplanets. Moreover, thanks to technological developments, it will allow the measure of the physical parameters (mass, angular momentum and electric charge of supermassive black holes in the center of ours and nearby galaxies.

  12. DISCOVERY OF UBIQUITOUS FAST-PROPAGATING INTENSITY DISTURBANCES BY THE CHROMOSPHERIC LYMAN ALPHA SPECTROPOLARIMETER (CLASP)

    International Nuclear Information System (INIS)

    Kubo, M.; Katsukawa, Y.; Suematsu, Y.; Kano, R.; Bando, T.; Narukage, N.; Ishikawa, R.; Hara, H.; Giono, G.; Tsuneta, S.; Ishikawa, S.; Shimizu, T.; Sakao, T.; Winebarger, A.; Kobayashi, K.; Cirtain, J.; Champey, P.; Auchère, F.; Bueno, J. Trujillo; Ramos, A. Asensio

    2016-01-01

    High-cadence observations by the slit-jaw (SJ) optics system of the sounding rocket experiment known as the Chromospheric Lyman Alpha Spectropolarimeter (CLASP) reveal ubiquitous intensity disturbances that recurrently propagate in either the chromosphere or the transition region or both at a speed much higher than the speed of sound. The CLASP/SJ instrument provides a time series of two-dimensional images taken with broadband filters centered on the Ly α line at a 0.6 s cadence. The multiple fast-propagating intensity disturbances appear in the quiet Sun and in an active region, and they are clearly detected in at least 20 areas in a field of view of 527″ × 527″ during the 5 minute observing time. The apparent speeds of the intensity disturbances range from 150 to 350 km s −1 , and they are comparable to the local Alfvén speed in the transition region. The intensity disturbances tend to propagate along bright elongated structures away from areas with strong photospheric magnetic fields. This suggests that the observed fast-propagating intensity disturbances are related to the magnetic canopy structures. The maximum distance traveled by the intensity disturbances is about 10″, and the widths are a few arcseconds, which are almost determined by a pixel size of 1.″03. The timescale of each intensity pulse is shorter than 30 s. One possible explanation for the fast-propagating intensity disturbances observed by CLASP is magnetohydrodynamic fast-mode waves.

  13. Neutral ISM, Ly α , and Lyman-continuum in the Nearby Starburst Haro 11

    Energy Technology Data Exchange (ETDEWEB)

    Rivera-Thorsen, T. Emil; Östlin, Göran; Hayes, Matthew; Puschnig, Johannes, E-mail: trive@astro.su.se [Department of Astronomy, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden)

    2017-03-01

    Star-forming galaxies are believed to be a major source of Lyman continuum (LyC) radiation responsible for reionizing the early universe. Direct observations of escaping ionizing radiation have however been sparse and with low escape fractions. In the local universe, only 10 emitters have been observed, with typical escape fractions of a few percent. The mechanisms regulating this escape need to be strongly evolving with redshift in order to account for the epoch of reionization. Gas content and star formation feedback are among the main suspects, known to both regulate neutral gas coverage and evolve with cosmic time. In this paper, we reanalyze Hubble Space Telescope ( HST )-Cosmic Origins Spectrograph (COS) spectrocopy of the first detected local LyC leaker, Haro 11. We examine the connection between LyC leakage and Ly α line shape, and feedback-influenced neutral interstellar medium (ISM) properties like kinematics and gas distribution. We discuss the two extremes of an optically thin, density bounded ISM and a riddled, optically thick, ionization bounded ISM, and how Haro 11 fits into theoretical predictions. We find that the most likely ISM model is a clumpy neutral medium embedded in a highly ionized medium with a combined covering fraction of unity and a residual neutral gas column density in the ionized medium high enough to be optically thick to Ly α , but low enough to be at least partly transparent to LyC and undetected in Si ii. This suggests that star formation feedback and galaxy-scale interaction events play a major role in opening passageways for ionizing radiation through the neutral medium.

  14. DISCOVERY OF UBIQUITOUS FAST-PROPAGATING INTENSITY DISTURBANCES BY THE CHROMOSPHERIC LYMAN ALPHA SPECTROPOLARIMETER (CLASP)

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, M.; Katsukawa, Y.; Suematsu, Y.; Kano, R.; Bando, T.; Narukage, N.; Ishikawa, R.; Hara, H.; Giono, G. [National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Tsuneta, S.; Ishikawa, S.; Shimizu, T.; Sakao, T. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Winebarger, A.; Kobayashi, K.; Cirtain, J. [NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States); Champey, P. [University of Alabama in Huntsville, 301 Sparkman Drive, Huntsville, AL 35899 (United States); Auchère, F. [Institut d’Astrophysique Spatiale, CNRS/Univ. Paris-Sud 11, Bâtiment 121, F-91405 Orsay (France); Bueno, J. Trujillo; Ramos, A. Asensio, E-mail: masahito.kubo@nao.ac.jp [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); and others

    2016-12-01

    High-cadence observations by the slit-jaw (SJ) optics system of the sounding rocket experiment known as the Chromospheric Lyman Alpha Spectropolarimeter (CLASP) reveal ubiquitous intensity disturbances that recurrently propagate in either the chromosphere or the transition region or both at a speed much higher than the speed of sound. The CLASP/SJ instrument provides a time series of two-dimensional images taken with broadband filters centered on the Ly α line at a 0.6 s cadence. The multiple fast-propagating intensity disturbances appear in the quiet Sun and in an active region, and they are clearly detected in at least 20 areas in a field of view of 527″ × 527″ during the 5 minute observing time. The apparent speeds of the intensity disturbances range from 150 to 350 km s{sup −1}, and they are comparable to the local Alfvén speed in the transition region. The intensity disturbances tend to propagate along bright elongated structures away from areas with strong photospheric magnetic fields. This suggests that the observed fast-propagating intensity disturbances are related to the magnetic canopy structures. The maximum distance traveled by the intensity disturbances is about 10″, and the widths are a few arcseconds, which are almost determined by a pixel size of 1.″03. The timescale of each intensity pulse is shorter than 30 s. One possible explanation for the fast-propagating intensity disturbances observed by CLASP is magnetohydrodynamic fast-mode waves.

  15. Neutral ISM, Ly α , and Lyman-continuum in the Nearby Starburst Haro 11

    International Nuclear Information System (INIS)

    Rivera-Thorsen, T. Emil; Östlin, Göran; Hayes, Matthew; Puschnig, Johannes

    2017-01-01

    Star-forming galaxies are believed to be a major source of Lyman continuum (LyC) radiation responsible for reionizing the early universe. Direct observations of escaping ionizing radiation have however been sparse and with low escape fractions. In the local universe, only 10 emitters have been observed, with typical escape fractions of a few percent. The mechanisms regulating this escape need to be strongly evolving with redshift in order to account for the epoch of reionization. Gas content and star formation feedback are among the main suspects, known to both regulate neutral gas coverage and evolve with cosmic time. In this paper, we reanalyze Hubble Space Telescope ( HST )-Cosmic Origins Spectrograph (COS) spectrocopy of the first detected local LyC leaker, Haro 11. We examine the connection between LyC leakage and Ly α line shape, and feedback-influenced neutral interstellar medium (ISM) properties like kinematics and gas distribution. We discuss the two extremes of an optically thin, density bounded ISM and a riddled, optically thick, ionization bounded ISM, and how Haro 11 fits into theoretical predictions. We find that the most likely ISM model is a clumpy neutral medium embedded in a highly ionized medium with a combined covering fraction of unity and a residual neutral gas column density in the ionized medium high enough to be optically thick to Ly α , but low enough to be at least partly transparent to LyC and undetected in Si ii. This suggests that star formation feedback and galaxy-scale interaction events play a major role in opening passageways for ionizing radiation through the neutral medium.

  16. Lyman-alpha detector designed for rocket measurements of the direct solar radiation at 121.5 nm

    International Nuclear Information System (INIS)

    Guineva, V.; Tashev, V.; Witt, G.; Gumbel, J.; Khaplanov, M.

    2007-01-01

    Rocket measurements of the direct Lyman-alpha radiation penetrating in the atmosphere were planned during the HotPay I rocket experiment, June 2006, Project ASLAF (Attenuation of the Solar Lyman-Alpha Flux), Andoya Rocket Range (ARR), Norway. The basic goal of ASLAF project was the study of the processes in the summer mesosphere and thermosphere (up to 110 km), at high latitudes using the Lyman-alpha measurements. The resonance transition 2 P- 2 S of the atomic hydrogen (Lyman-alpha emission) is the strongest and most conspicuous feature in the solar EUV spectrum. Due to the favourable circumstance, that the Lyman-alpha wavelength (121.5 nm) coincides with a minimum of the O 2 absorption spectrum, the direct Lyman-alpha radiation penetrates well in the mesosphere. The Lyman-alpha radiation is the basic agent of the NO molecules ionization, thus generating the ionospheric D-layer, and of the water vapour photolysis, being one of the main H 2 O loss processes. The Lyman-alpha radiation transfer depends on the resonance scattering from the hydrogen atoms in the atmosphere and on the O 2 absorption. Since the Lyman-alpha extinction in the atmosphere is a measure for the column density of the oxygen molecules, the atmospheric temperature profile can be calculated thereof. The detector of solar Lyman-alpha radiation was manufactured in the Stara Zagora Department of the Solar-Terrestrial Influences Laboratory (STIL). Its basic part is an ionization chamber, filled in with NO. A 60 V power supply is applied to the chamber. The produced photoelectric current from the sensor is fed to a 2-channels amplifier, providing an analogue signal. The characteristics of the Lyman-alpha detector were studied. It passed successfully all tests and the results showed that the instrument could be used in rocket experiments to measure the Lyman-alpha flux. From the measurements of the detector, the Lyman-alpha vertical profile can be obtained. The forthcoming scientific data analysis will

  17. Discovery of a transient U-band dropout in a lyman break survey: A tidally disrupted star at z=3.3?

    International Nuclear Information System (INIS)

    Stern, Daniel; van Dokkum, P.G.; Nugent, Peter; Sand, D.J.; Ellis, R.S.; Sullivan, Mark; Bloom, J.S.; Frail, D.A.; Kneib, J.-P.; Koopmans, L.V.E.; Treu, Tommaso

    2004-01-01

    We report the discovery of a transient source in the central regions of galaxy cluster A267. The object, which we call ''PALS-1'', was found in a survey aimed at identifying highly magnified Lyman break galaxies in the fields of intervening rich clusters. At discovery, the source had Un>24:7 (2 ; AB), g 1/4 21:96 0:12, and very blue g r and ri colors; i.e., PALS-1 was a ''U-band dropout'', characteristic of star-forming galaxies and quasars at z 3. However, 3 months later the source had faded by more than 3 mag. Further observations showed a continued decline in luminosity, to R>26:4 at 7 months after discovery. Although the apparent brightness suggests a supernova at roughly the cluster redshift, we show that the photometry and light curve argue against any known type of supernova at any redshift. The spectral energy distribution and location near the center of a galaxy cluster are consistent with the hypothesis that PALS-1 is a gravitationally lensed transient at z 3:3. If this interpretation is correct, the source is magnified by a factor of 4 7, and two counter images are predicted. Our lens model predicts that there are time delays between the three images of 110 yr and that we have witnessed the final occurrence of the transient. The intense luminosity (MAB 23:5 after correcting for lensing) and blue UV continuum (implying T k50; 000 K) argue that the source may have been a flare resulting from the tidal disruption of a star by a 106108 M black hole. Regardless of its physical nature, PALS-1 highlights the importance of monitoring regions of high magnification in galaxy clusters for distant time-varying phenomena

  18. Planck 2015 results: XV. Gravitational lensing

    DEFF Research Database (Denmark)

    Ade, P. A R; Aghanim, N.; Arnaud, M.

    2016-01-01

    We present the most significant measurement of the cosmic microwave background (CMB) lensing potential to date (at a level of 40σ), using temperature and polarization data from the Planck 2015 full-mission release. Using a polarization-only estimator, we detect lensing at a significance of 5σ. We...

  19. Lenses and Perception: Investigations with Light

    Science.gov (United States)

    Akcay, Hakan

    2005-01-01

    The main goals of these activities are to help students learn how a convex lens can serve as a magnifying lens and how light travels and creates images. These explorations will introduce middle school students to different types of lenses and how they work. Students will observe and describe how lenses bend light that passes through them and how…

  20. BAYESIAN INFERENCE OF CMB GRAVITATIONAL LENSING

    Energy Technology Data Exchange (ETDEWEB)

    Anderes, Ethan [Department of Statistics, University of California, Davis, CA 95616 (United States); Wandelt, Benjamin D.; Lavaux, Guilhem [Sorbonne Universités, UPMC Univ Paris 06 and CNRS, UMR7095, Institut d’Astrophysique de Paris, F-75014, Paris (France)

    2015-08-01

    The Planck satellite, along with several ground-based telescopes, has mapped the cosmic microwave background (CMB) at sufficient resolution and signal-to-noise so as to allow a detection of the subtle distortions due to the gravitational influence of the intervening matter distribution. A natural modeling approach is to write a Bayesian hierarchical model for the lensed CMB in terms of the unlensed CMB and the lensing potential. So far there has been no feasible algorithm for inferring the posterior distribution of the lensing potential from the lensed CMB map. We propose a solution that allows efficient Markov Chain Monte Carlo sampling from the joint posterior of the lensing potential and the unlensed CMB map using the Hamiltonian Monte Carlo technique. The main conceptual step in the solution is a re-parameterization of CMB lensing in terms of the lensed CMB and the “inverse lensing” potential. We demonstrate a fast implementation on simulated data, including noise and a sky cut, that uses a further acceleration based on a very mild approximation of the inverse lensing potential. We find that the resulting Markov Chain has short correlation lengths and excellent convergence properties, making it promising for applications to high-resolution CMB data sets in the future.

  1. Electron beams, lenses, and optics. Volume 1

    International Nuclear Information System (INIS)

    El-Kareh, A.B.; El-Kareh, J.C.J.

    1970-01-01

    This book treats the ideal case where all lenses are assumed to be free from errors. It presents a thorough mathematical analysis of the electrostatic immersion lens, both symmetrical and asymetrical, and covers the einzel lens and the symmetrical magnetic lens in detail. The authors have obtained data on these lenses by means of a digital computer and present them in tabular form

  2. Solutions for care of silicone hydrogel lenses.

    Science.gov (United States)

    Willcox, Mark D P

    2013-01-01

    During wear of contact lenses on a daily wear basis, it is necessary to disinfect the lens overnight before reinserting the lens the next day. The ability of the solutions used for this to disinfect lenses and lens cases is important for safe lens wear. The literature on the disinfecting ability of multipurpose disinfecting solutions (MPDS) commonly used with silicone hydrogel lenses reported during the period 2000 to 2012 is reviewed, as this is the period of time during which these lenses have been commercially available. Particular emphasis is placed on the ability of disinfecting solutions to control colonization of lens cases by microbes and changes in composition and use of the solutions. In addition, the literature is reviewed on ways of minimizing lens case microbial contamination. Maintaining the hygiene of contact lenses and lens cases is important in minimizing various forms of corneal infiltrative events that occur during lens wear. Although lens case contamination is not associated with different lenses, it is determined by use of different MPDS. MPDS that allow more frequent or heavy contamination of cases by Gram-negative bacteria are associated with a higher incidence of corneal infiltrative events. MPDS are now available that contain dual disinfectants. Wiping lens cases with tissues or using lens cases that incorporate silver are associated with reductions in contamination in clinical trials. Similarly, using MPDS to rub and rinse lenses before disinfection may reduce levels of microbes on lenses. The MPDS also contain surfactants that help reduce deposition and denaturation of proteins on lenses. Improvements in MPDS formulations and hygiene practices may help to reduce the incidence of adverse events that are seen during use with silicone hydrogel lenses.

  3. Galex Lyman-alpha Emitters: Physical Properties, Luminosity Bimodality, And Morphologies.

    Science.gov (United States)

    Mallery, Ryan P.

    2010-01-01

    The Galaxy Evolution Explorer spectroscopic survey has uncovered a large statistically significant sample of Lyman-alpha emitters at z sim0.3. ACS imaging of these sources in the COSMOS and AEGIS deep fields reveals that these Lyman-alpha emitters consist of two distinct galaxy morphologies, face on spiral galaxies and compact starburst/merging systems. The morphology bimodality also results in a bimodal distribution of optical luminosity. A comparison between the UV photometry and MIPS 24 micron detections of these sources indicates that they are bluer, and have less dust extinction than similar star forming galaxies that lack Lyman-alpha detection. Our findings show how the global gas and dust distribution of star forming galaxies inhibits Lyman-alpha emission in star forming galaxies. GALEX is a NASA Small Explorer, launched in April 2003. We gratefully acknowledge NASA's support for construction, operation, and science analysis for the GALEX mission, developed in cooperation with the CNES of France and the Korean Ministry of Science and Technology.

  4. MUSE spectroscopy and deep observations of a unique compact JWST target, lensing cluster CLIO

    Science.gov (United States)

    Griffiths, Alex; Conselice, Christopher J.; Alpaslan, Mehmet; Frye, Brenda L.; Diego, Jose M.; Zitrin, Adi; Yan, Haojing; Ma, Zhiyuan; Barone-Nugent, Robert; Bhatawdekar, Rachana; Driver, Simon P.; Robotham, Aaron S. G.; Windhorst, Rogier A.; Wyithe, J. Stuart B.

    2018-04-01

    We present the results of a VLT MUSE/FORS2 and Spitzer survey of a unique compact lensing cluster CLIO at z = 0.42, discovered through the GAMA survey using spectroscopic redshifts. Compact and massive clusters such as this are understudied, but provide a unique prospective on dark matter distributions and for finding background lensed high-z galaxies. The CLIO cluster was identified for follow-up observations due to its almost unique combination of high-mass and dark matter halo concentration, as well as having observed lensing arcs from ground-based images. Using dual band optical and infra-red imaging from FORS2 and Spitzer, in combination with MUSE optical spectroscopy we identify 89 cluster members and find background sources out to z = 6.49. We describe the physical state of this cluster, finding a strong correlation between environment and galaxy spectral type. Under the assumption of an NFW profile, we measure the total mass of CLIO to be M200 = (4.49 ± 0.25) × 1014 M⊙. We build and present an initial strong-lensing model for this cluster, and measure a relatively low intracluster light (ICL) fraction of 7.21 ± 1.53 per cent through galaxy profile fitting. Due to its strong potential for lensing background galaxies and its low ICL, the CLIO cluster will be a target for our 110 h James Webb Space Telescope `Webb Medium-Deep Field' (WMDF) GTO program.

  5. Lens Model and Time Delay Predictions for the Sextuply Lensed Quasar SDSS J2222+2745*

    Science.gov (United States)

    Sharon, Keren; Bayliss, Matthew B.; Dahle, Hakon; Florian, Michael K.; Gladders, Michael D.; Johnson, Traci L.; Paterno-Mahler, Rachel; Rigby, Jane R.; Whitaker, Katherine E.; Wuyts, Eva

    2017-01-01

    SDSS J2222+2745 is a galaxy cluster at z = 0.49, strongly lensing a quasar at z = 2.805 into six widely separated images. In recent Hubble Space Telescope imaging of the field, we identify additional multiply lensed galaxies and confirm the sixth quasar image that was identified by Dahle et al. We used the Gemini-North telescope to measure a spectroscopic redshift of z = 4.56 of one of the lensed galaxies. These data are used to refine the lens model of SDSS J2222+2745, compute the time delay and magnifications of the lensed quasar images, and reconstruct the source image of the quasar host and a lensed galaxy at z = 2.3. This galaxy also appears in absorption in our Gemini spectra of the lensed quasar, at a projected distance of 34 kpc. Our model is in agreement with the recent time delay measurements of Dahle et al., who found T(sub AB) = 47.7 +/- 6.0 days and T(sub AC) = 722 +/- 24 days. We use the observed time delays to further constrain the model, and find that the model-predicted time delays of the three faint images of the quasar are T(sub AD) = 502+/- 68 days, T( sub AE) = 611 +/- 75 days, and T(sub AF) = 415 +/- 72 days. We have initiated a follow-up campaign to measure these time delays with Gemini North. Finally, we present initial results from an X-ray monitoring program with Swift, indicating the presence of hard X-ray emission from the lensed quasar, as well as extended X-ray emission from the cluster itself, which is consistent with the lensing mass measurement and the cluster velocity dispersion.

  6. LENS MODEL AND TIME DELAY PREDICTIONS FOR THE SEXTUPLY LENSED QUASAR SDSS J2222+2745

    Energy Technology Data Exchange (ETDEWEB)

    Sharon, Keren; Johnson, Traci L.; Paterno-Mahler, Rachel [Department of Astronomy, University of Michigan, 1085 S. University Avenue, Ann Arbor, MI 48109 (United States); Bayliss, Matthew B. [Colby College, 5800 Mayflower Hill, Waterville, 04901, Maine (United States); Dahle, Håkon [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway); Florian, Michael K.; Gladders, Michael D. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Rigby, Jane R. [Astrophysics Science Division, Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Whitaker, Katherine E. [Department of Astronomy, University of Massachusetts-Amherst, Amherst, MA 01003 (United States); Wuyts, Eva, E-mail: kerens@umich.edu [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstr. 1, D-85741 Garching (Germany)

    2017-01-20

    SDSS J2222+2745 is a galaxy cluster at z = 0.49, strongly lensing a quasar at z = 2.805 into six widely separated images. In recent Hubble Space Telescope imaging of the field, we identify additional multiply lensed galaxies and confirm the sixth quasar image that was identified by Dahle et al. We used the Gemini-North telescope to measure a spectroscopic redshift of z = 4.56 of one of the lensed galaxies. These data are used to refine the lens model of SDSS J2222+2745, compute the time delay and magnifications of the lensed quasar images, and reconstruct the source image of the quasar host and a lensed galaxy at z = 2.3. This galaxy also appears in absorption in our Gemini spectra of the lensed quasar, at a projected distance of 34 kpc. Our model is in agreement with the recent time delay measurements of Dahle et al., who found τ {sub AB} = 47.7 ± 6.0 days and τ {sub AC} = −722 ± 24 days. We use the observed time delays to further constrain the model, and find that the model-predicted time delays of the three faint images of the quasar are τ {sub AD} = 502 ± 68 days, τ {sub AE} = 611 ± 75 days, and τ {sub AF} = 415 ± 72 days. We have initiated a follow-up campaign to measure these time delays with Gemini North. Finally, we present initial results from an X-ray monitoring program with Swift , indicating the presence of hard X-ray emission from the lensed quasar, as well as extended X-ray emission from the cluster itself, which is consistent with the lensing mass measurement and the cluster velocity dispersion.

  7. Pulsar emission amplified and resolved by plasma lensing in an eclipsing binary.

    Science.gov (United States)

    Main, Robert; Yang, I-Sheng; Chan, Victor; Li, Dongzi; Lin, Fang Xi; Mahajan, Nikhil; Pen, Ue-Li; Vanderlinde, Keith; van Kerkwijk, Marten H

    2018-05-01

    Radio pulsars scintillate because their emission travels through the ionized interstellar medium along multiple paths, which interfere with each other. It has long been realized that, independent of their nature, the regions responsible for the scintillation could be used as 'interstellar lenses' to localize pulsar emission regions 1,2 . Most such lenses, however, resolve emission components only marginally, limiting results to statistical inferences and detections of small positional shifts 3-5 . As lenses situated close to their source offer better resolution, it should be easier to resolve emission regions of pulsars located in high-density environments such as supernova remnants 6 or binaries in which the pulsar's companion has an ionized outflow. Here we report observations of extreme plasma lensing in the 'black widow' pulsar, B1957+20, near the phase in its 9.2-hour orbit at which its emission is eclipsed by its companion's outflow 7-9 . During the lensing events, the observed radio flux is enhanced by factors of up to 70-80 at specific frequencies. The strongest events clearly resolve the emission regions: they affect the narrow main pulse and parts of the wider interpulse differently. We show that the events arise naturally from density fluctuations in the outer regions of the outflow, and we infer a resolution of our lenses that is comparable to the pulsar's radius, about 10 kilometres. Furthermore, the distinct frequency structures imparted by the lensing are reminiscent of what is observed for the repeating fast radio burst FRB 121102, providing observational support for the idea that this source is observed through, and thus at times strongly magnified by, plasma lenses 10 .

  8. An integral-field spectroscopic strong lens survey

    International Nuclear Information System (INIS)

    Bolton, Adam S; Burles, Scott

    2007-01-01

    We present the observational results of a survey for strong gravitational lens systems consisting of extended emission-line galaxies lensed by intervening early-type galaxies, conducted using integral field units (IFUs) of the Magellan IMACS and Gemini GMOS-N spectrographs. These data are highly valuable for corroborating the lensing interpretation of Hubble Space Telescope imaging data. We show that in many cases, ground-based IFU spectroscopy is in fact competitive with space-based imaging for the measurement of the mass model parameters of the lensing galaxy. We demonstrate a novel technique of three-dimensional gravitational lens modeling for a single lens system with a resolved lensed rotation curve. We also describe the details of our custom IFU data analysis software, which performs optimal multi-fiber extraction, relative and absolute wavelength calibration to a few hundredths of a pixel RMS and nearly Poisson-limited sky subtraction

  9. Adherence of Pseudomonas aeruginosa to contact lenses

    International Nuclear Information System (INIS)

    Miller, M.J.

    1988-01-01

    The purpose of this research was to examined the interactions of P. aeruginosa with hydrogel contact lenses and other substrata, and characterize adherence to lenses under various physiological and physicochemical conditions. Isolates adhered to polystyrene, glass, and hydrogel lenses. With certain lens types, radiolabeled cells showed decreased adherence with increasing water content of the lenses, however, this correlation with not found for all lenses. Adherence to rigid gas permeable lenses was markedly greater than adherence to hydrogels. Best adherence occurred near pH 7 and at a sodium chloride concentration of 50 mM. Passive adhesion of heat-killed cells to hydrogels was lower than the adherence obtained of viable cells. Adherence to hydrogels was enhanced by mucin, lactoferrin, lysozyme, IgA, bovine serum albumin, and a mixture of these macromolecules. Adherence to coated and uncoated lenses was greater with a daily-wear hydrogel when compared with an extended-wear hydrogel of similar polymer composition. Greater adherence was attributed to a higher concentration of adsorbed macromolecules on the 45% water-content lens in comparison to the 55% water-content lens

  10. <strong>Mini-project>

    DEFF Research Database (Denmark)

    Katajainen, Jyrki

    2008-01-01

    In this project the goal is to develop the safe * family of containers for the CPH STL. The containers to be developed should be safer and more reliable than any of the existing implementations. A special focus should be put on strong exception safety since none of the existing prototypes available...

  11. Mesh-free free-form lensing - I. Methodology and application to mass reconstruction

    Science.gov (United States)

    Merten, Julian

    2016-09-01

    Many applications and algorithms in the field of gravitational lensing make use of meshes with a finite number of nodes to analyse and manipulate data. Specific examples in lensing are astronomical CCD images in general, the reconstruction of density distributions from lensing data, lens-source plane mapping or the characterization and interpolation of a point spread function. We present a numerical framework to interpolate and differentiate in the mesh-free domain, defined by nodes with coordinates that follow no regular pattern. The framework is based on radial basis functions (RBFs) to smoothly represent data around the nodes. We demonstrate the performance of Gaussian RBF-based, mesh-free interpolation and differentiation, which reaches the sub-percent level in both cases. We use our newly developed framework to translate ideas of free-form mass reconstruction from lensing on to the mesh-free domain. By reconstructing a simulated mock lens we find that strong-lensing only reconstructions achieve <10 per cent accuracy in the areas where these constraints are available but provide poorer results when departing from these regions. Weak-lensing only reconstructions give <10 per cent accuracy outside the strong-lensing regime, but cannot resolve the inner core structure of the lens. Once both regimes are combined, accurate reconstructions can be achieved over the full field of view. The reconstruction of a simulated lens, using constraints that mimics real observations, yields accurate results in terms of surface-mass density, Navarro-Frenk-White profile (NFW) parameters, Einstein radius and magnification map recovery, encouraging the application of this method to real data.

  12. Nanofocusing refractive X-ray lenses

    Energy Technology Data Exchange (ETDEWEB)

    Boye, Pit

    2010-02-05

    This thesis is concerned with the optimization and development of the production of nanofocusing refractive X-ray lenses. These optics made of either silicon or diamond are well-suited for high resolution X-ray microscopy. The goal of this work is the design of a reproducible manufacturing process which allows the production of silicon lenses with high precision, high quality and high piece number. Furthermore a process for the production of diamond lenses is to be developed and established. In this work, the theoretical basics of X-rays and their interaction with matter are described. Especially, aspects of synchrotron radiation are emphasized. Important in X-ray microscopy are the different optics. The details, advantages and disadvantages, in particular those of refractive lenses are given. To achieve small X-ray beams well beyond the 100 nm range a small focal length is required. This is achieved in refractive lenses by moving to a compact lens design where several single lenses are stacked behind each other. The, so-called nanofocusing refractive lenses (NFLs) have a parabolic cylindrical shape with lateral structure sizes in the micrometer range. NFLs are produced by using micro-machining techniques. These micro-fabrication processes and technologies are introduced. The results of the optimization and the final fabrication process for silicon lenses are presented. Subsequently, two experiments that are exemplary for the use of NFLs, are introduced. The rst one employs a high-resolution scanning fluorescence mapping of a geological sample, and the second one is a coherent x-ray diffraction imaging (CXDI) experiment. CXDI is able to reconstruct the illuminated object from recorded coherent diffraction patterns. In a scanning mode, referred to as ptychography, this method is even able to reconstruct the illumination and the object simultaneously. Especially the reconstructed illumination and the possibility of computed propagation of the wave field along the

  13. Nanofocusing refractive X-ray lenses

    International Nuclear Information System (INIS)

    Boye, Pit

    2010-01-01

    This thesis is concerned with the optimization and development of the production of nanofocusing refractive X-ray lenses. These optics made of either silicon or diamond are well-suited for high resolution X-ray microscopy. The goal of this work is the design of a reproducible manufacturing process which allows the production of silicon lenses with high precision, high quality and high piece number. Furthermore a process for the production of diamond lenses is to be developed and established. In this work, the theoretical basics of X-rays and their interaction with matter are described. Especially, aspects of synchrotron radiation are emphasized. Important in X-ray microscopy are the different optics. The details, advantages and disadvantages, in particular those of refractive lenses are given. To achieve small X-ray beams well beyond the 100 nm range a small focal length is required. This is achieved in refractive lenses by moving to a compact lens design where several single lenses are stacked behind each other. The, so-called nanofocusing refractive lenses (NFLs) have a parabolic cylindrical shape with lateral structure sizes in the micrometer range. NFLs are produced by using micro-machining techniques. These micro-fabrication processes and technologies are introduced. The results of the optimization and the final fabrication process for silicon lenses are presented. Subsequently, two experiments that are exemplary for the use of NFLs, are introduced. The rst one employs a high-resolution scanning fluorescence mapping of a geological sample, and the second one is a coherent x-ray diffraction imaging (CXDI) experiment. CXDI is able to reconstruct the illuminated object from recorded coherent diffraction patterns. In a scanning mode, referred to as ptychography, this method is even able to reconstruct the illumination and the object simultaneously. Especially the reconstructed illumination and the possibility of computed propagation of the wave field along the

  14. Strong interactions

    International Nuclear Information System (INIS)

    Froissart, Marcel

    1976-01-01

    Strong interactions are introduced by their more obvious aspect: nuclear forces. In hadron family, the nucleon octet, OMEGA - decuplet, and quark triply are successively considered. Pion wave having been put at the origin of nuclear forces, low energy phenomena are described, the force being explained as an exchange of structure corresponding to a Regge trajectory in a variable rotating state instead of the exchange of a well defined particle. At high energies the concepts of pomeron, parton and stratons are introduced, pionization and fragmentation are briefly differentiated [fr

  15. Nanofocusing Parabolic Refractive X-Ray Lenses

    International Nuclear Information System (INIS)

    Schroer, C.G.; Kuhlmann, M.; Hunger, U.T.; Guenzler, T.F.; Kurapova, O.; Feste, S.; Lengeler, B.; Drakopoulos, M.; Somogyi, A.; Simionovici, A. S.; Snigirev, A.; Snigireva, I.

    2004-01-01

    Parabolic refractive x-ray lenses with short focal distance can generate intensive hard x-ray microbeams with lateral extensions in the 100nm range even at short distance from a synchrotron radiation source. We have fabricated planar parabolic lenses made of silicon that have a focal distance in the range of a few millimeters at hard x-ray energies. In a crossed geometry, two lenses were used to generate a microbeam with a lateral size of 330nm by 110nm at 25keV in a distance of 41.8m from the synchrotron radiation source. First microdiffraction and fluorescence microtomography experiments were carried out with these lenses. Using diamond as lens material, microbeams with lateral size down to 20nm and below are conceivable in the energy range from 10 to 100keV

  16. Development of a Lyman-α Imaging Solar Telescope for the Satellite

    Directory of Open Access Journals (Sweden)

    M. Jang

    2005-09-01

    Full Text Available Long term observations of full-disk Lyman-α irradiance have been made by the instruments on various satellites. In addition, several sounding rockets dating back to the 1950s and up through the present have measured the Lyman-α irradiance. Previous full disk Lyman-α images of the sun have been very interesting and useful scientifically, but have been only five-minute ``snapshots" obtained on sounding rocket flights. All of these observations to date have been snapshots, with no time resolution to observe changes in the chromospheric structure as a result of the evolving magnetic field, and its effect on the Lyman-α intensity. The Lyman-α Imaging Solar Telescope(LIST can provide a unique opportunity for the study of the sun in the Lyman-α region with the high time and spatial resolution for the first time. Up to the 2nd year development, the preliminary design of the optics, mechanical structure and electronics system has been completed. Also the mechanical structure analysis, thermal analysis were performed and the material for the structure was chosen as a result of these analyses. And the test plan and the verification matrix were decided. The operation systems, technical and scientific operation, were studied and finally decided. Those are the technical operation, mechanical working modes for the observation and safety, the scientific operation and the process of the acquired data. The basic techniques acquired through the development of satellite based solar telescope are essential for the construction of space environment forecast system in the future. The techniques which we developed through this study, like mechanical, optical and data processing techniques, could be applied extensively not only to the process of the future production of flight models of this kind, but also to the related industries. Also, we can utilize the scientific achievements which are obtained throughout the project. And these can be utilized to build a high

  17. Lyman alpha emission in nearby star-forming galaxies with the lowest metallicities and the highest [OIII]/[OII] ratios

    Science.gov (United States)

    Izotov, Yuri

    2017-08-01

    The Lyman alpha line of hydrogen is the strongest emission line in galaxies and the tool of predilection for identifying and studying star-forming galaxies over a wide range of redshifts, especially in the early universe. However, it has become clear over the years that not all of the Lyman alpha radiation escapes, due to its resonant scattering on the interstellar and intergalactic medium, and absorption by dust. Although our knowledge of the high-z universe depends crucially on that line, we still do not have a complete understanding of the mechanisms behind the production, radiative transfer and escape of Lyman alpha in galaxies. We wish here to investigate these mechanisms by studying the properties of the ISM in a unique sample of 8 extreme star-forming galaxies (SFGs) that have the highest excitation in the SDSS spectral data base. These dwarf SFGs have considerably lower stellar masses and metallicities, and higher equivalent widths and [OIII]5007/[OII]3727 ratios compared to all nearby SFGs with Lyman alpha emission studied so far with COS. They are, however, very similar to the dwarf Lyman alpha emitters at redshifts 3-6, which are thought to be the main sources of reionization in the early Universe. By combining the HST/COS UV data with data in the optical range, and using photoionization and radiative transfer codes, we will be able to study the properties of the Lyman alpha in these unique objects, derive column densities of the neutral hydrogen N(HI) and compare them with N(HI) obtained from the HeI emission-line ratios in the optical spectra. We will derive Lyman alpha escape fractions and indirectly Lyman continuum escape fractions.

  18. Revised Unfilling Procedure for Solid Lithium Lenses

    International Nuclear Information System (INIS)

    Leveling, A.

    2003-01-01

    A procedure for unfilling used lithium lenses to has been described in Pbar Note 664. To date, the procedure has been used to disassemble lenses 20, 21, 17, 18, and 16. As a result of this work, some parts of the original procedure were found to be time consuming and ineffective. Modifications to the original procedure have been made to streamline the process and are discussed in this note. The revised procedure is included in this note.

  19. Microbial adherence to cosmetic contact lenses.

    Science.gov (United States)

    Chan, Ka Yin; Cho, Pauline; Boost, Maureen

    2014-08-01

    To investigate whether cosmetic contact lenses (CCL) with surface pigments affect microbial adherence. Fifteen brands of CCL were purchased from optical, non-optical retail outlets, and via the Internet. A standardized rub-off test was performed on each CCL (five lenses per brand) to confirm the location of the pigments. The rub-off test comprised gentle rubbing on the surfaces of each CCL with wetted cotton buds for a maximum of 20 rubs per surface. A new set of CCL (five lenses per brand) were incubated in Pseudomonas aeruginosa overnight. Viable counts of adhered bacteria were determined by the number of colony-forming units (CFU) on agar media on each lens. The adherence of P. aeruginosa as well as Staphylococcus aureus and Serratia marcescens to three brands of CCL (A-C) (five lenses per brand) were also compared to their adherences on their clear counterparts. Only two of the 15 brands of CCL tested (brands B and C) had pigments that did not detach with the rub-off test. The remaining 13 brands of CCL all failed the rub-off test and these lenses showed higher P. aeruginosa adherence (8.7 × 10(5)-1.9 × 10(6) CFU/lens). Brands B and C lenses showed at least six times less bacterial adhesion than the other 13 brands. Compared to their clear counterparts, bacterial adherence to brands B and C lenses did not differ significantly, whereas brand A lenses showed significantly higher adherence. Surface pigments on CCL resulted in significantly higher bacterial adherence. Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  20. Comments on the Gravitational lensing Magnification

    OpenAIRE

    Takashi, HAMANA; Astronomical Institute, Tohoku University

    1998-01-01

    We rederive a relation between gravitational lensing magnification relative to the standard Friedmann distance and one relative to the Dyer-Roeder distance by investigating the null geodesic deviation equation. We show that the relation comes from a natural consequence of the definition of the lensing magnification matrices and is not based on the averaging of the magnifications, which has conventionally been used to derive it. We therefore conclude that the relation is true for each individu...

  1. Comments on the gravitational lensing magnification

    OpenAIRE

    Hamana, Takashi

    1998-01-01

    We rederive a relation between gravitational lensing magnification relative to the standard Friedmann distance and one relative to the Dyer-Roeder distance by investigating the null geodesic deviation equation. We show that the relation comes from a natural consequence of the definition of the lensing magnification matrices and is not based on the averaging of the magnifications, which has conventionally been used to derive it. We therefore conclude that the relation is true for each individu...

  2. Factors influencing bacterial adhesion to contact lenses.

    Science.gov (United States)

    Dutta, Debarun; Cole, Nerida; Willcox, Mark

    2012-01-01

    The process of any contact lens related keratitis generally starts with the adhesion of opportunistic pathogens to contact lens surface. This article focuses on identifying the factors which have been reported to affect bacterial adhesion to contact lenses. Adhesion to lenses differs between various genera/species/strains of bacteria. Pseudomonas aeruginosa, which is the predominant causative organism, adheres in the highest numbers to both hydrogel and silicone hydrogel lenses in vitro. The adhesion of this strain reaches maximum numbers within 1h in most in vitro studies and a biofilm has generally formed within 24 h of cells adhering to the lens surface. Physical and chemical properties of contact lens material affect bacterial adhesion. The water content of hydroxyethylmethacrylate (HEMA)-based lenses and their iconicity affect the ability of bacteria to adhere. The higher hydrophobicity of silicone hydrogel lenses compared to HEMA-based lenses has been implicated in the higher numbers of bacteria that can adhere to their surfaces. Lens wear has different effects on bacterial adhesion, partly due to differences between wearers, responses of bacterial strains and the ability of certain tear film proteins when bound to a lens surface to kill certain types of bacteria.

  3. Predicting gravitational lensing by stellar remnants

    Science.gov (United States)

    Harding, Alexander J.; Stefano, R. Di; Lépine, S.; Urama, J.; Pham, D.; Baker, C.

    2018-03-01

    Gravitational lensing provides a means to measure mass that does not rely on detecting and analysing light from the lens itself. Compact objects are ideal gravitational lenses, because they have relatively large masses and are dim. In this paper, we describe the prospects for predicting lensing events generated by the local population of compact objects, consisting of 250 neutron stars, five black holes, and ≈35 000 white dwarfs. By focusing on a population of nearby compact objects with measured proper motions and known distances from us, we can measure their masses by studying the characteristics of any lensing event they generate. Here, we concentrate on shifts in the position of a background source due to lensing by a foreground compact object. With Hubble Space Telescope, JWST, and Gaia, measurable centroid shifts caused by lensing are relatively frequent occurrences. We find that 30-50 detectable events per decade are expected for white dwarfs. Because relatively few neutron stars and black holes have measured distances and proper motions, it is more difficult to compute realistic rates for them. However, we show that at least one isolated neutron star has likely produced detectable events during the past several decades. This work is particularly relevant to the upcoming data releases by the Gaia mission and also to data that will be collected by JWST. Monitoring predicted microlensing events will not only help to determine the masses of compact objects, but will also potentially discover dim companions to these stellar remnants, including orbiting exoplanets.

  4. Dark-Matter in Galaxies from Gravitational Lensing and Stellar Dynamics Studies

    NARCIS (Netherlands)

    Koopmans, L. V. E.; Corbett, IF

    2010-01-01

    Strong gravitational lensing and stellar dynamics provide two complementary methods in the study of the mass distribution of dark matter in galaxies out to redshift of unity. They are particularly powerful in the determination of the total mass and the density profile of mass early-type galaxies on

  5. Lensing of Fast Radio Bursts by Plasma Structures in Host Galaxies

    NARCIS (Netherlands)

    Cordes, J.M.; Wasserman, I.; Hessels, J.W.T.; Lazio, T.J.W.; Chatterjee, S.; Wharton, R.S.

    2017-01-01

    The amplitudes of fast radio bursts (FRBs) can be strongly modulated by plasma lenses in their host galaxies, including that of the repeating FRB 121102 at ∼1 Gpc luminosity distance. Caustics require the lens’ dispersion measure depth ({{DM}}{\\ell }), scale size (a), and distance from the source

  6. Physical and morphological properties of z ~ 3 Lyman break galaxies: dependence on Lyα line emission

    Science.gov (United States)

    Pentericci, L.; Grazian, A.; Scarlata, C.; Fontana, A.; Castellano, M.; Giallongo, E.; Vanzella, E.

    2010-05-01

    Aims: We investigate the physical and morphological properties of Lyman break galaxies (LBGs) at redshift ~2.5 to ~3.5, to determine if and how they depend on the nature and strength of the Lyα emission. Methods: We selected U-dropout galaxies from the z-detected GOODS-MUSIC catalog by adapting the classical Lyman break criteria on the GOODS filter set. We kept only those galaxies with spectroscopic confirmation, mainly from VIMOS and FORS public observations. Using the full multi-wavelength 14-bands information (U to IRAC), we determined the physical properties of the galaxies through a standard spectral energy distribution fitting procedure with the updated Charlot & Bruzual (2009) templates. We also added other relevant observations of the GOODS field, i.e. the 24 μm observations from Spitzer/MIPS and the 2 MSec Chandra X-ray observations. Finally, using non parametric diagnostics (Gini, Concentration, Asymmetry, M20 and ellipticity), we characterized the rest-frame UV morphologies of the galaxies. We then analyzed how these physical and morphological properties correlate with the presence of the Lyα emission line in the optical spectra. Results: We find that unlike at higher redshift, the dependence of physical properties on the Lyα line is milder: galaxies without Lyα in emission tend to be more massive and dustier than the rest of the sample, but all other parameters, ages, star formation rates (SFR), X-ray emission and UV morphology do not depend strongly on the presence of the Lyα emission. A simple scenario where all LBGs have intrinsically high Lyα emission, but where the dust and neutral hydrogen content (which shapes the final appearance of the Lyα) depend on the mass of the galaxies, is able to reproduce the majority of the observed properties at z˜3. Some modification might be needed to account for the observed evolution of these properties with cosmic epoch, which is also discussed.

  7. New constraints on Lyman-α opacity using 92 quasar lines of sight

    Science.gov (United States)

    Bosman, Sarah E. I.; Fan, Xiaohui; Jiang, Linhua; Reed, Sophie; Matsuoka, Yoshiki; Becker, George; Rorai, Albert

    2018-05-01

    The large scatter in Lyman-α opacity at z > 5.3 has been an ongoing mystery, prompting a flurry of numerical models. A uniform ultra-violet background has been ruled out at those redshifts, but it is unclear whether any proposed models produce sufficient inhomogeneities. In this paper we provide an update on the measurement which first highlighted the issue: Lyman-α effective optical depth along high-z quasar lines of sight. We nearly triple on the previous sample size in such a study thanks to the cooperation of the DES-VHS, SHELLQs, and SDSS collaborations as well as new reductions and spectra. We find that a uniform UVB model is ruled out at 5.1 < z < 5.3, as well as higher redshifts, which is perplexing. We provide the first such measurements at z ~ 6. None of the numerical models we confronted to this data could reproduce the observed scatter.

  8. Determination of magnetic field direction in tokamaks from laser-induced Lyman-α fluorescence

    International Nuclear Information System (INIS)

    Voslamber, D.

    1988-04-01

    Resonant laser scattering in the Lyman-α line of hydrogen is investigated as a possible tool for measuring the magnetic field direction in tokamak plasmas. The method is based on the depolarisation-dependence of the scattering process. Limitations arising from depolarising collisions are studied in detail by employing a previously developed theory for the collisional redistribution of light. An error analysis is performed to derive the expected experimental precision under various plasma conditions and for laser energies ranging between 1 micronJ and 10 mJ. This analysis also includes the measurement of neutral hydrogen densities. It is shown that with presently available laser powers application of the method would be restricted to the border regions of the plasma. Application to the central regions would require further developments in laser technology, especially with regard to higher powers at the wavelength of Lyman-α and (or) to fast repetition rates

  9. Are the brightest Lyman Alpha Emitters at zD5.7 primeval galaxies?

    Science.gov (United States)

    Lidman, Christopher; Hayes, Matthew; Jones, Heath; Meisenheimer, Klaus; Tapken, Christian; Westra, Eduard

    2009-04-01

    Wide-field, narrow-band surveys have proven to be effective at finding very high redshift galaxies that emit brightly in the Lyman alpha line - the so-called Lyman alpha emitters (LAEs). It was through this technique that the most distant spectroscopically confirmed galaxy, a galaxy at zD6.96 (Iye et al. 2006), was discovered. Considerable effort is currently being spent on discovering these galaxies at ever higher redshifts by extending this technique into the near-IR. In contrast to this effort, there has been relatively little work on understanding these galaxies. In particular, how do LAEs relate to other high redshift galaxies, such as those discovered through drop out techniques, and, more importantly, what role LAEs play in re-ionising the universe, if any. We recently discovered two extremely luminous LAEs at zD5.7. These LAEs are among the brightest LAEs ever discovered at this redshift. In a recent paper by Mao et al. (2007), the brightest LAEs are associated to the most massive halos. One of these targets was successfully observed with the IRAC 3.6 micron imager on Spitzer during cycle 5. These data, when combined with constraints that we derive from our deep ground-based spectroscopic data, indicate that the bulk of the flux at 3.6 microns comes from a stellar population that is considserably older than the stars that dominate the flux in the UV. We propose to complete the project and image the second target. These data will enable us to estimate the age and mass of the stellar burst that produces the Lyman alpha line, to estimate the contribution from an older stellar population and to estimate the fraction of Lyman continuum photons that escape the galaxy and are thus available to re-ionise the universe.

  10. Late Rectal Toxicity on RTOG 94-06: Analysis Using a Mixture Lyman Model

    International Nuclear Information System (INIS)

    Tucker, Susan L.; Dong Lei; Bosch, Walter R.; Michalski, Jeff; Winter, Kathryn; Mohan, Radhe; Purdy, James A.; Kuban, Deborah; Lee, Andrew K.; Cheung, M. Rex; Thames, Howard D.; Cox, James D.

    2010-01-01

    Purpose: To estimate the parameters of the Lyman normal-tissue complication probability model using censored time-to-event data for Grade ≥2 late rectal toxicity among patients treated on Radiation Therapy Oncology Group 94-06, a dose-escalation trial designed to determine the maximum tolerated dose for three-dimensional conformal radiotherapy of prostate cancer. Methods and Materials: The Lyman normal-tissue complication probability model was fitted to data from 1,010 of the 1,084 patients accrued on Radiation Therapy Oncology Group 94-06 using an approach that accounts for censored observations. Separate fits were obtained using dose-volume histograms for whole rectum and dose-wall histograms for rectal wall. Results: With a median follow-up of 7.2 years, the crude incidence of Grade ≥2 late rectal toxicity was 15% (n = 148). The parameters of the Lyman model fitted to dose-volume histograms data, with 95% profile-likelihood confidence intervals, were TD 50 = 79.1 Gy (75.3 Gy, 84.3 Gy), m = 0.146 (0.107, 0.225), and n = 0.077 (0.041, 0.156). The fit based on dose-wall histogram data was not significantly different. Patients with cardiovascular disease had a significantly higher incidence of late rectal toxicity (p = 0.015), corresponding to a dose-modifying factor of 5.3%. No significant association with late rectal toxicity was found for diabetes, hypertension, rectal volume, rectal length, neoadjuvant hormone therapy, or prescribed dose per fraction (1.8 Gy vs. 2 Gy). Conclusions: These results, based on a large cohort of patients from a multi-institutional trial, are expected to be widely representative of the ability of the Lyman model to describe the long-term risk of Grade ≥2 late rectal toxicity after three-dimensional conformal radiotherapy of prostate cancer.

  11. Performance Characterization of UV Science Cameras Developed for the Chromospheric Lyman-Alpha Spectro-Polarimeter

    Science.gov (United States)

    Champey, P.; Kobayashi, K.; Winebarger, A.; Cirtain, J.; Hyde, D.; Robertson, B.; Beabout, D.; Beabout, B.; Stewart, M.

    2014-01-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras will be built and tested for flight with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The goal of the CLASP mission is to observe the scattering polarization in Lyman-alpha and to detect the Hanle effect in the line core. Due to the nature of Lyman-alpha polarization in the chromosphere, strict measurement sensitivity requirements are imposed on the CLASP polarimeter and spectrograph systems; science requirements for polarization measurements of Q/I and U/I are 0.1 percent in the line core. CLASP is a dual-beam spectro-polarimeter, which uses a continuously rotating waveplate as a polarization modulator, while the waveplate motor driver outputs trigger pulses to synchronize the exposures. The CCDs are operated in frame-transfer mode; the trigger pulse initiates the frame transfer, effectively ending the ongoing exposure and starting the next. The strict requirement of 0.1 percent polarization accuracy is met by using frame-transfer cameras to maximize the duty cycle in order to minimize photon noise. Coating the e2v CCD57-10 512x512 detectors with Lumogen-E coating allows for a relatively high (30 percent) quantum efficiency at the Lyman-alpha line. The CLASP cameras were designed to operate with 10 e-/pixel/second dark current, 25 e- read noise, a gain of 2.0 +/- 0.5 and 1.0 percent residual non-linearity. We present the results of the performance characterization study performed on the CLASP prototype camera; dark current, read noise, camera gain and residual non-linearity.

  12. Small-scale structure and the Lyman-α forest baryon acoustic oscillation feature

    Science.gov (United States)

    Hirata, Christopher M.

    2018-02-01

    The baryon-acoustic oscillation (BAO) feature in the Lyman-α forest is a key probe of the cosmic expansion rate at redshifts z ˜ 2.5, well before dark energy is believed to have become significant. A key advantage of the BAO as a standard ruler is that it is a sharp feature and hence is more robust against broad-band systematic effects than other cosmological probes. However, if the Lyman-α forest transmission is sensitive to the initial streaming velocity of the baryons relative to the dark matter, then the BAO peak position can be shifted. Here we investigate this sensitivity using a suite of hydrodynamic simulations of small regions of the intergalactic medium with a range of box sizes and physics assumptions; each simulation starts from initial conditions at the kinematic decoupling era (z ˜ 1059), undergoes a discrete change from neutral gas to ionized gas thermal evolution at reionization (z ˜ 8), and is finally processed into a Lyman-α forest transmitted flux cube. Streaming velocities suppress small-scale structure, leading to less violent relaxation after reionization. The changes in the gas distribution and temperature-density relation at low redshift are more subtle, due to the convergent temperature evolution in the ionized phase. The change in the BAO scale is estimated to be of the order of 0.12 per cent at z = 2.5; some of the major uncertainties and avenues for future improvement are discussed. The predicted streaming velocity shift would be a subdominant but not negligible effect (of order 0.26σ) for the upcoming DESI Lyman-α forest survey, and exceeds the cosmic variance floor.

  13. Lyman-alpha transit observations of the warm rocky exoplanet GJ1132b

    Science.gov (United States)

    Waalkes, William; Berta-Thompson, Zachory K.; Charbonneau, David; Irwin, Jonathan; Newton, Elisabeth; Dittmann, Jason; Bourrier, Vincent; Ehrenreich, David; Kempton, Eliza; Will

    2018-06-01

    GJ1132b is one of the few known Earth-sized planets, and at 12pc away it is also one of the closest known transiting planets. With an equilibrium temperature of 500 K, this planet is too hot to be habitable but we can use it to learn about the presence and volatile content of rocky planet atmospheres around M dwarf stars. Using Hubble STIS spectra obtained during primary transit, we search for a Lyman-α transit. If we were to observe a deep Lyman-α transit, that would indicate the presence of a neutral hydrogen envelope flowing from GJ1132b. On the other hand, ruling out deep absorption from neutral hydrogen may indicate that this planet has either retained its volatiles or lost them very early in the star’s life. We carry out this analysis by extracting 1D spectra from the STIS pipeline, splitting the time-tagged spectra into higher resolution samples, and producing light curves of the red and blue wings of the Lyman-α line. We fit for the baseline stellar flux and transit depths in order to constrain the characteristics of the cloud of neutral hydrogen gas that may surround the planet. We do not conclusively detect a transit but the results provide an upper limit for the transit depth. We also analyze the stellar variability and Lyman-α spectrum of GJ1132, a slowly-rotating 0.18 solar mass M dwarf with previously uncharacterized UV activity. Understanding the role that UV variability plays in planetary atmospheres and volatile retention is crucial to assess atmospheric evolution and the habitability of cooler rocky planets.

  14. Adhesion of Pseudomonas aeruginosa to orthokeratology and alignment lenses.

    Science.gov (United States)

    Choo, Jennifer D; Holden, Brien A; Papas, Eric B; Willcox, Mark D P

    2009-02-01

    To determine whether contact lenses designed for orthokeratology (OK) are colonized by greater numbers of bacteria compared with standard (alignment fitted) design rigid gas permeable lenses before and after lens wear. Eighteen 1-year-old cats were randomly fitted with an OK lens in one eye and an alignment fitted (AF) lens in the other eye. Both lenses were made in the same diameter and central thickness and of the same material. Two separate wearing periods of 2 weeks and 6 weeks were used. After each wearing period, lenses were soaked in Pseudomonas aeruginosa (6294 or 6206) for 10 min. The lenses were then reinserted onto their respective corneas for a wearing period of 16 hours after which lenses were collected and remaining adhered bacteria quantified. Unworn control lenses were also soaked and bacteria enumerated for comparison. There were no significant differences in the number of bacteria adherent to unworn AF and OK lenses. Analysis of lenses after wear showed OK lenses retained significantly higher numbers of viable bacteria than AF lenses in all studies. OK lenses retain more bacteria than AF rigid gas permeable lenses after bacteria-loaded overnight lens wear. This may increase the risk for an infection in OK patients should suitable conditions be present. Specific education on the cleaning of OK lenses is essential.

  15. The Lyman Alpha Imaging-Monitor Experiment (LAIME) for TESIS/CORONAS-PHOTON

    Science.gov (United States)

    Damé, L.; Koutchmy, S.; Kuzin, S.; Lamy, P.; Malherbe, J.-M.; Noëns, J.-C.

    LAIME the Lyman Alpha Imaging-Monitor Experiment is a remarkably simple no mechanisms and compact 100x100x400 mm full Sun imager to be flown with TESIS on the CORONAS-PHOTON mission launch expected before mid-2008 As such it will be the only true chromospheric imager to be flown in the next years supporting TESIS EUV-XUV imaging SDO and the Belgian LYRA Lyman Alpha flux monitor on the ESA PROBA-2 microsatellite launch expected in September 2007 We will give a short description of this unique O60 mm aperture imaging telescope dedicated to the investigating of the magnetic sources of solar variability in the UV and chromospheric and coronal disruptive events rapid waves Moreton waves disparitions brusques of prominences filaments eruptions and CMEs onset The resolution pixel is 2 7 arcsec the field of view 1 4 solar radius and the acquisition cadence could be as high as 1 image minute The back thinned E2V CCD in the focal plane is using frame transfer to avoid shutter and mechanisms Further more the double Lyman Alpha filtering allows a 40 AA FWHM bandwidth and excellent rejection yet providing a vacuum seal design of the telescope MgF2 entrance window Structural stability of the telescope focal length 1 m is preserved by a 4-INVAR bars design with Aluminium compensation in a large pm 10 o around 20 o

  16. Investigating the Lyman photon escape in local starburst galaxies with the Cosmic Origins Spectrograph ★

    Science.gov (United States)

    Hernandez, Svea; Leitherer, Claus; Boquien, Médéric; Buat, Véronique; Burgarella, Denis; Calzetti, Daniela; Noll, Stefan

    2018-04-01

    We present a study of 7 star-forming galaxies from the Cosmic Evolution Survey (COSMOS) observed with the Cosmic Origins Spectrograph (COS) on board the Hubble Space Telescope (HST). The galaxies are located at relatively low redshifts, z ˜0.3, with morphologies ranging from extended and disturbed to compact and smooth. To complement the HST observations we also analyze observations taken with the VIMOS spectrograph on the Very Large Telescope (VLT). In our galaxy sample we identify three objects with double peak Lyman-α profiles similar to those seen in Green Pea compact galaxies and measure peak separations of 655, 374, and 275 km s-1. We measure Lyman-α escape fractions with values ranging between 5-13%. Given the low flux levels in the individual COS exposures we apply a weighted stacking approach to obtain a single spectrum. From this COS combined spectrum we infer upper limits for the absolute and relative Lyman continuum escape fractions of f_abs(LyC) = 0.4^{+10.1}_{-0.4}% and f_res(LyC) = 1.7^{+15.2}_{-1.7}%, respectively. Finally, we find that most of these galaxies have moderate UV and optical SFRs (SFRs ≲ 10 M⊙ yr-1).

  17. Precision cosmology with weak gravitational lensing

    Science.gov (United States)

    Hearin, Andrew P.

    In recent years, cosmological science has developed a highly predictive model for the universe on large scales that is in quantitative agreement with a wide range of astronomical observations. While the number and diversity of successes of this model provide great confidence that our general picture of cosmology is correct, numerous puzzles remain. In this dissertation, I analyze the potential of planned and near future galaxy surveys to provide new understanding of several unanswered questions in cosmology, and address some of the leading challenges to this observational program. In particular, I study an emerging technique called cosmic shear, the weak gravitational lensing produced by large scale structure. I focus on developing strategies to optimally use the cosmic shear signal observed in galaxy imaging surveys to uncover the physics of dark energy and the early universe. In chapter 1 I give an overview of a few unsolved mysteries in cosmology and I motivate weak lensing as a cosmological probe. I discuss the use of weak lensing as a test of general relativity in chapter 2 and assess the threat to such tests presented by our uncertainty in the physics of galaxy formation. Interpreting the cosmic shear signal requires knowledge of the redshift distribution of the lensed galaxies. This redshift distribution will be significantly uncertain since it must be determined photometrically. In chapter 3 I investigate the influence of photometric redshift errors on our ability to constrain dark energy models with weak lensing. The ability to study dark energy with cosmic shear is also limited by the imprecision in our understanding of the physics of gravitational collapse. In chapter 4 I present the stringent calibration requirements on this source of uncertainty. I study the potential of weak lensing to resolve a debate over a long-standing anomaly in CMB measurements in chapter 5. Finally, in chapter 6 I summarize my findings and conclude with a brief discussion of my

  18. Constraining the primordial power spectrum from SNIa lensing dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Dayan, Ido [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kalaydzhyan, Tigran [State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics and Astronomy

    2013-09-15

    The (absence of detecting) lensing dispersion of Supernovae type Ia (SNIa) can be used as a novel and extremely efficient probe of cosmology. In this preliminary example we analyze its consequences for the primordial power spectrum. The main setback is the knowledge of the power spectrum in the non-linear regime, 1 Mpc{sup -1}lensing dispersion and conservative estimates in this regime of wavenumbers, we show how the current upper bound {sigma}{sub {mu}}(z=1)<0.12 on existing data gives strong indirect constraints on the primordial power spectrum. The probe extends our handle on the spectrum to a total of 12-15 inflation e-folds. These constraints are so strong that they are already ruling out a large portion of the parameter space allowed by PLANCK for running {alpha}{identical_to}dn{sub s}/d ln k and running of running {beta}{identical_to}d{sup 2}n{sub s}/d ln k{sup 2}. The bounds follow a linear relation to a very good accuracy. A conservative bound disfavours any enhancement above the line {beta}(k{sub 0})=0.032-0.41{alpha}(k{sub 0}) and a realistic estimate disfavours any enhancement above the line {beta}(k{sub 0})=0.019-0.45{alpha}(k{sub 0}).

  19. RELICS: A Candidate Galaxy Arc at z~10 and Other Brightly Lensed z>6 Galaxies

    Science.gov (United States)

    Salmon, Brett; Coe, Dan; Bradley, Larry; Bradac, Marusa; Huang, Kuang-Han; Oesch, Pascal; Brammer, Gabriel; Stark, Daniel P.; Sharon, Keren; Trenti, Michele; Avila, Roberto J.; Ogaz, Sara; Acebron, Ana; Andrade-Santos, Felipe; Carrasco, Daniela; Cerny, Catherine; Cibirka, Nathália; Dawson, William; Frye, Brenda; Hoag, Austin; Jones, Christine; Mainali, Ramesh; Ouchi, Masami; Paterno-Mahler, Rachel; Rodney, Steven; Umetsu, Keiichi; Zitrin, Adi; RELICS

    2018-01-01

    Massive foreground galaxy clusters magnify and distort the light of objects behind them, permitting a view into both the extremely distant and intrinsically faint galaxy populations. We present here some of the most brightly lensed z>6 galaxy candidates known from the Reionization Lensing Cluster Survey (RELICS) and the discovery of a particularly fortuitous z~10 galaxy candidate which has been arced by the effects of strong gravitational lensing. The z~10 candidate has a lensed H-band magnitude of 25.8 AB mag and a high lensing magnification (~4-7). The inferred upper limits on the stellar mass (log [M_star /M_Sun]=9.5) and star formation rate (log [SFR/(M_Sun/yr)]=1.5) indicate that this candidate is a typical star-forming galaxy on the z>6 SFR-M_star relation. We rule out the only low-z solution as unphysical based on the required stellar mass, dust attenuation, size, and [OIII] EW needed for a z~2 SED to match the data. Finally, we reconstruct the source-plane image and estimate the candidate's physical size at z~10, finding a half-light radius of r_e 9 candidates. While the James Webb Space Telescope will detect z>10 with ease, this rare candidate offers the potential for unprecedented spatial resolution less than 500 Myr after the Big Bang.

  20. Cross-correlation of weak lensing and gamma rays: implications for the nature of dark matter

    Science.gov (United States)

    Tröster, Tilman; Camera, Stefano; Fornasa, Mattia; Regis, Marco; van Waerbeke, Ludovic; Harnois-Déraps, Joachim; Ando, Shin'ichiro; Bilicki, Maciej; Erben, Thomas; Fornengo, Nicolao; Heymans, Catherine; Hildebrandt, Hendrik; Hoekstra, Henk; Kuijken, Konrad; Viola, Massimo

    2017-05-01

    We measure the cross-correlation between Fermi gamma-ray photons and over 1000 deg2 of weak lensing data from the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS), the Red Cluster Sequence Lensing Survey (RCSLenS), and the Kilo Degree Survey (KiDS). We present the first measurement of tomographic weak lensing cross-correlations and the first application of spectral binning to cross-correlations between gamma rays and weak lensing. The measurements are performed using an angular power spectrum estimator while the covariance is estimated using an analytical prescription. We verify the accuracy of our covariance estimate by comparing it to two internal covariance estimators. Based on the non-detection of a cross-correlation signal, we derive constraints on weakly interacting massive particle (WIMP) dark matter. We compute exclusion limits on the dark matter annihilation cross-section , decay rate Γdec and particle mass mDM. We find that in the absence of a cross-correlation signal, tomography does not significantly improve the constraining power of the analysis. Assuming a strong contribution to the gamma-ray flux due to small-scale clustering of dark matter and accounting for known astrophysical sources of gamma rays, we exclude the thermal relic cross-section for particle masses of mDM ≲ 20 GeV.

  1. The skewed weak lensing likelihood: why biases arise, despite data and theory being sound.

    Science.gov (United States)

    Sellentin, Elena; Heymans, Catherine; Harnois-Déraps, Joachim

    2018-04-01

    We derive the essentials of the skewed weak lensing likelihood via a simple Hierarchical Forward Model. Our likelihood passes four objective and cosmology-independent tests which a standard Gaussian likelihood fails. We demonstrate that sound weak lensing data are naturally biased low, since they are drawn from a skewed distribution. This occurs already in the framework of ΛCDM. Mathematically, the biases arise because noisy two-point functions follow skewed distributions. This form of bias is already known from CMB analyses, where the low multipoles have asymmetric error bars. Weak lensing is more strongly affected by this asymmetry as galaxies form a discrete set of shear tracer particles, in contrast to a smooth shear field. We demonstrate that the biases can be up to 30% of the standard deviation per data point, dependent on the properties of the weak lensing survey and the employed filter function. Our likelihood provides a versatile framework with which to address this bias in future weak lensing analyses.

  2. Gravitationally Lensed Quasars in Gaia: II. Discovery of 24 Lensed Quasars

    Science.gov (United States)

    Lemon, Cameron A.; Auger, Matthew W.; McMahon, Richard G.; Ostrovski, Fernanda

    2018-04-01

    We report the discovery, spectroscopic confirmation and preliminary characterisation of 24 gravitationally lensed quasars identified using Gaia observations. Candidates were selected in the Pan-STARRS footprint with quasar-like WISE colours or as photometric quasars from SDSS, requiring either multiple detections in Gaia or a single Gaia detection near a morphological galaxy. The Pan-STARRS grizY images were modelled for the most promising candidates and 60 candidate systems were followed up with the William Herschel Telescope. 13 of the lenses were discovered as Gaia multiples and 10 as single Gaia detections near galaxies. We also discover 1 lens identified through a quasar emission line in an SDSS galaxy spectrum. The lenses have median image separation 2.13″ and the source redshifts range from 1.06 to 3.36. 4 systems are quadruply-imaged and 20 are doubly-imaged. Deep CFHT data reveal an Einstein ring in one double system. We also report 12 quasar pairs, 10 of which have components at the same redshift and require further follow-up to rule out the lensing hypothesis. We compare the properties of these lenses and other known lenses recovered by our search method to a complete sample of simulated lenses to show the lenses we are missing are mainly those with small separations and higher source redshifts. The initial Gaia data release only catalogues all images of ˜ 30% of known bright lensed quasars, however the improved completeness of Gaia data release 2 will help find all bright lensed quasars on the sky.

  3. Relative radiosensitivity of rat lenses as a function of age

    International Nuclear Information System (INIS)

    Merriam, G.R. Jr.; Szechter, A.

    1975-01-01

    The effect of age on the development of radiation cataracts in rat lenses has been investigated using the Columbia--Sherman rat as an experiment model. A detailed pattern of age dependence was obtained at several different dose levels. In general at dose levels from 200 to 300 rads the lens changes occurred sooner and progressed faster in the adult lenses than in young lenses. In the dose range from 300 rads to 900 rads opacities developed sooner in the young lenses but progression was faster and severe opacities developed sooner in adult lenses. Above 900 rads opacities developed sooner and progressed faster in the young lenses. (U.S.)

  4. Golden gravitational lensing systems from the Sloan Lens ACS Survey - II. SDSS J1430+4105: a precise inner total mass profile from lensing alone

    Science.gov (United States)

    Eichner, Thomas; Seitz, Stella; Bauer, Anne

    2012-12-01

    We study the Sloan Lens ACS (SLACS) survey strong-lensing system SDSS J1430+4105 at zl = 0.285. The lensed source (zs = 0.575) of this system has a complex morphology with several subcomponents. Its subcomponents span a radial range from 4 to 10 kpc in the plane of the lens. Therefore, we can constrain the slope of the total projected mass profile around the Einstein radius from lensing alone. We measure a density profile that is slightly but not significantly shallower than isothermal at the Einstein radius. We decompose the mass of the lensing galaxy into a de Vaucouleurs component to trace the stars and an additional dark component. The spread of multiple-image components over a large radial range also allows us to determine the amplitude of the de Vaucouleurs and dark matter components separately. We get a mass-to-light ratio of M de Vauc LB ≈ (5.5±1.5) M⊙L⊙,B and a dark matter fraction within the Einstein radius of ≈20 to 40 per cent. Modelling the star formation history assuming composite stellar populations at solar metallicity to the galaxy's photometry yields a mass-to-light ratio of M, salp LB ≈ 4.0-1.3+0.6 M⊙L⊙,B and M, chab LB ≈ 2.3-0.8+0.3 M⊙L⊙,B for Salpeter and Chabrier initial mass functions, respectively. Hence, the mass-to-light ratio derived from lensing is more Salpeter like, in agreement with results for massive Coma galaxies and other nearby massive early-type galaxies. We examine the consequences of the galaxy group in which the lensing galaxy is embedded, showing that it has little influence on the mass-to-light ratio obtained for the de Vaucouleurs component of the lensing galaxy. Finally, we decompose the projected, azimuthally averaged 2D density distribution of the de Vaucouleurs and dark matter components of the lensing signal into spherically averaged 3D density profiles. We can show that the 3D dark and luminous matter density within the Einstein radius (REin ≈ 0.6 Reff) of this SLACS galaxy is similar to the

  5. DESIGN OF THE MULTIORDER INTRAOCULAR LENSES

    Directory of Open Access Journals (Sweden)

    V. G. Kolobrodov

    2015-01-01

    Full Text Available Intraocular lenses (IOLs are used to replace the natural crystalline lens of the eye. Just few basic designs of IOLs are used clinically. Multiorder diffractive lenses (MODL which operate simultaneously in several diffractive orders were proposed to decrease the chromatic aberration. Properties analysis of MODL showed a possibility to use them to develop new designs of IOLs. The purpose of this paper was to develop a new method of designing of multiorder intraocular lenses with decreased chromatic aberration. The theoretical research of the lens properties was carried out. The diffraction efficiency dependence with the change of wavelength was studied. A computer simulation of MODL in a schematic model of the human eye was carried out. It is found the capability of the multiorder diffractive lenses to focus polychromatic light into a segment on the optical axis with high diffraction efficiency. At each point of the segment is present each component of the spectral range, which will build a color image in combination. The paper describes the new design method of intraocular lenses with reduced chromaticism and with endless adaptation. An optical system of an eye with an intraocular lens that provides sharp vision of objects located at a distance of 700 mm to infinity is modeled.

  6. Plasma lenses for focusing relativistic electron beams

    International Nuclear Information System (INIS)

    Govil, R.; Wheeler, S.; Leemans, W.

    1997-01-01

    The next generation of colliders require tightly focused beams with high luminosity. To focus charged particle beams for such applications, a plasma focusing scheme has been proposed. Plasma lenses can be overdense (plasma density, n p much greater than electron beam density, n b ) or underdense (n p less than 2 n b ). In overdense lenses the space-charge force of the electron beam is canceled by the plasma and the remaining magnetic force causes the electron beam to self-pinch. The focusing gradient is nonlinear, resulting in spherical aberrations. In underdense lenses, the self-forces of the electron beam cancel, allowing the plasma ions to focus the beam. Although for a given beam density, a uniform underdense lens produces smaller focusing gradients than an overdense lens, it produces better beam quality since the focusing is done by plasma ions. The underdense lens can be improved by tapering the density of the plasma for optimal focusing. The underdense lens performance can be enhanced further by producing adiabatic plasma lenses to avoid the Oide limit on spot size due to synchrotron radiation by the electron beam. The plasma lens experiment at the Beam Test Facility (BTF) is designed to study the properties of plasma lenses in both overdense and underdense regimes. In particular, important issues such as electron beam matching, time response of the lens, lens aberrations and shot-to-shot reproducibility are being investigated

  7. Weak lensing in generalized gravity theories

    International Nuclear Information System (INIS)

    Acquaviva, Viviana; Baccigalupi, Carlo; Perrotta, Francesca

    2004-01-01

    We extend the theory of weak gravitational lensing to cosmologies with generalized gravity, described in the Lagrangian by a generic function depending on the Ricci scalar and a nonminimal coupled scalar field. We work out the generalized Poisson equations relating the dynamics of the fluctuating components to the two gauge-invariant scalar gravitational potentials, fixing the contributions from the modified background expansion and fluctuations. We show how the lensing equation gets modified by the cosmic expansion as well as by the presence of anisotropic stress, which is non-null at the linear level both in scalar-tensor gravity and in theories where the gravitational Lagrangian term features a nonminimal dependence on the Ricci scalar. Starting from the geodesic deviation, we derive the generalized expressions for the shear tensor and projected lensing potential, encoding the spacetime variation of the effective gravitational constant and isolating the contribution of the anisotropic stress, which introduces a correction due to the spatial correlation between the gravitational potentials. Finally, we work out the expressions of the lensing convergence power spectrum as well as the correlation between the lensing potential and the integrated Sachs-Wolfe effect affecting cosmic microwave background total intensity and polarization anisotropies. To illustrate phenomenologically the effects, we work out approximate expressions for the quantities above in extended quintessence scenarios where the scalar field coupled to gravity plays the role of the dark energy

  8. Stationary nonimaging lenses for solar concentration.

    Science.gov (United States)

    Kotsidas, Panagiotis; Chatzi, Eleni; Modi, Vijay

    2010-09-20

    A novel approach for the design of refractive lenses is presented, where the lens is mounted on a stationary aperture and the Sun is tracked by a moving solar cell. The purpose of this work is to design a quasi-stationary concentrator by replacing the two-axis tracking of the Sun with internal motion of the miniaturized solar cell inside the module. Families of lenses are designed with a variation of the simultaneous multiple surface technique in which the sawtooth genetic algorithm is implemented to optimize the geometric variables of the optic in order to produce high fluxes for a range of incidence angles. Finally, we show examples of the technique for lenses with 60° and 30° acceptance half-angles, with low to medium attainable concentrations.

  9. Gravitational Lensing from a Spacetime Perspective

    Directory of Open Access Journals (Sweden)

    Perlick Volker

    2004-09-01

    Full Text Available The theory of gravitational lensing is reviewed from a spacetime perspective, without quasi-Newtonian approximations. More precisely, the review covers all aspects of gravitational lensing where light propagation is described in terms of lightlike geodesics of a metric of Lorentzian signature. It includes the basic equations and the relevant techniques for calculating the position, the shape, and the brightness of images in an arbitrary general-relativistic spacetime. It also includes general theorems on the classification of caustics, on criteria for multiple imaging, and on the possible number of images. The general results are illustrated with examples of spacetimes where the lensing features can be explicitly calculated, including the Schwarzschild spacetime, the Kerr spacetime, the spacetime of a straight string, plane gravitational waves, and others.

  10. Weak lensing in the Dark Energy Survey

    Science.gov (United States)

    Troxel, Michael

    2016-03-01

    I will present the current status of weak lensing results from the Dark Energy Survey (DES). DES will survey 5000 square degrees in five photometric bands (grizY), and has already provided a competitive weak lensing catalog from Science Verification data covering just 3% of the final survey footprint. I will summarize the status of shear catalog production using observations from the first year of the survey and discuss recent weak lensing science results from DES. Finally, I will report on the outlook for future cosmological analyses in DES including the two-point cosmic shear correlation function and discuss challenges that DES and future surveys will face in achieving a control of systematics that allows us to take full advantage of the available statistical power of our shear catalogs.

  11. Aberration characteristics of immersion lenses for LVSEM

    International Nuclear Information System (INIS)

    Khursheed, Anjam

    2002-01-01

    This paper investigates the on-axis aberration characteristics of various immersion objective lenses for low voltage scanning electron microscopy (LVSEM). A simple aperture lens model is used to generate smooth axial field distributions. The simulation results show that mixed field electric-magnetic immersion lenses are predicted to have between 1.5 and 2 times smaller aberration limited probe diameters than their pure-field counterparts. At a landing energy of 1 keV, mixed field immersion lenses operating at the vacuum electrical field breakdown limit are predicted to have on-axis aberration coefficients between 50 and 60 μm, yielding an ultimate image resolution of below 1 nm. These aberrations lie in the same range as those for LVSEM systems that employ aberration correctors

  12. Nanofocusing parabolic refractive x-ray lenses

    International Nuclear Information System (INIS)

    Schroer, C.G.; Kuhlmann, M.; Hunger, U.T.; Guenzler, T.F.; Kurapova, O.; Feste, S.; Frehse, F.; Lengeler, B.; Drakopoulos, M.; Somogyi, A.; Simionovici, A.S.; Snigirev, A.; Snigireva, I.; Schug, C.; Schroeder, W.H.

    2003-01-01

    Parabolic refractive x-ray lenses with short focal distance can generate intensive hard x-ray microbeams with lateral extensions in the 100 nm range even at a short distance from a synchrotron radiation source. We have fabricated planar parabolic lenses made of silicon that have a focal distance in the range of a few millimeters at hard x-ray energies. In a crossed geometry, two lenses were used to generate a microbeam with a lateral size of 380 nm by 210 nm at 25 keV in a distance of 42 m from the synchrotron radiation source. Using diamond as the lens material, microbeams with a lateral size down to 20 nm and below are conceivable in the energy range from 10 to 100 keV

  13. Soft-contact-lenses-induced complications

    Directory of Open Access Journals (Sweden)

    Suvajac Gordana

    2008-01-01

    Full Text Available Background/Aim. Soft contact lenses occupy significant place in ophthalmology, both in the correction of refraction anomalies and in the treatment of many eye diseases. The number of patients that wear soft contact lenses for the purpose of correcting ametropia is constantly increasing. Due to the increasing number of wearers, the percentage of complications that can lead to serious eye damage and serious vision loss is also increasing. The aim of this study was to point out the most common complications related to soft contact lens use. Methods. In the period from 1995−2004 this prospective study included 510 patients wearing soft contact lenses for correcting ametropia. None of the patients wore contact lenses before and none suffered from any system or local diseases that could affected the development of eventual complications. The study took seven years with the patients who wore conventional lenses and three years with those who wore replacement contact lenses. All the necessary ophthalmologic examinations were done (visual acuity, refractokeratometry, the quantity of tear film, biomicroscopic examination of anterior eye segment. All the complications were filmed by video camera. Results. Of all the patients, 19 had blepharitis, 73 suffered from “dry eye”, 57 had conjunctival hyperemia, 12 had conjunctivitis, 34 had gigantopapillary conjunctivitis (GPC, 93 had punctiform epitheliopathy, 20 had corneal infiltration, one patient had keratitis, 91 had corneal vascularisation, and 95 patients had corneal deposits. Conclusion. Both the type and frequency of complications related to soft contact lens use in our group of patients, proved to be significant. Some of this complications (keratitis can significantly damage vision and lead to loss of vision and sometimes can require operative treatment.

  14. The Mathematical Theory of Multifocal Lenses

    Institute of Scientific and Technical Information of China (English)

    Jacob RUBINSTEIN

    2017-01-01

    This paper presents the fundamental optical concepts of designing multifocal ophthalmic lenses and the mathematical methods associated with them.In particular,it is shown that the design methodology is heavily based on differential geometric ideas such as Willmore surfaces.A key role is played by Hamilton's eikonal functions.It is shown that these functions capture all the information on the local blur and distortion created by the lenses.Along the way,formulas for computing the eikonal functions are derived.Finally,the author lists a few intriguing mathematical problems and novel concepts in optics as future projects.

  15. Achromatic Cooling Channel with Li Lenses

    Energy Technology Data Exchange (ETDEWEB)

    Balbekov, V. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2002-04-29

    A linear cooling channel with Li lenses, solenoids, and 201 MHz RF cavities is considered. A special lattice design is used to minimize chromatic aberrations by suppression of several betatron resonances. Transverse emittance of muon beam decreases from 2 mm to 0.5 mm at the channel of about 110 m length. Longitudinal heating is modest, therefore transmission of the channel is rather high: 96% without decay and 90% with decay. Minimal beam emittance achievable by similar channel estimated as about 0.25 mm at surface field of Li lenses 10 T.

  16. High-speed optical signal processing using time lenses

    DEFF Research Database (Denmark)

    Galili, Michael; Hu, Hao; Guan, Pengyu

    2015-01-01

    This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle.......This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle....

  17. Dynamics of Fermat potentials in nonperturbative gravitational lensing

    International Nuclear Information System (INIS)

    Frittelli, Simonetta; Newman, Ezra T.

    2002-01-01

    We present a framework, based on the null-surface formulation of general relativity, for discussing the dynamics of Fermat potentials for gravitational lensing in a generic situation without approximations of any kind. Additionally, we derive two lens equations: one for the case of thick compact lenses and the other one for lensing by gravitational waves. These equations in principle generalize the astrophysical scheme for lensing by removing the thin-lens approximation while retaining the weak fields

  18. Discovery of a Transient U-Band Dropout in a Lyman Break Survey: A Tidally Disrupted Star at z=3.3?

    Science.gov (United States)

    Stern, Daniel; van Dokkum, P. G.; Nugent, Peter; Sand, D. J.; Ellis, R. S.; Sullivan, Mark; Bloom, J. S.; Frail, D. A.; Kneib, J.-P.; Koopmans, L. V. E.; Treu, Tommaso

    2004-09-01

    We report the discovery of a transient source in the central regions of galaxy cluster A267. The object, which we call ``PALS-1,'' was found in a survey aimed at identifying highly magnified Lyman break galaxies in the fields of intervening rich clusters. At discovery, the source had Un>24.7 (2 σ AB), g=21.96+/-0.12, and very blue g-r and r-i colors; i.e., PALS-1 was a ``U-band dropout,'' characteristic of star-forming galaxies and quasars at z~3. However, 3 months later the source had faded by more than 3 mag. Further observations showed a continued decline in luminosity, to R>26.4 at 7 months after discovery. Although the apparent brightness suggests a supernova at roughly the cluster redshift, we show that the photometry and light curve argue against any known type of supernova at any redshift. The spectral energy distribution and location near the center of a galaxy cluster are consistent with the hypothesis that PALS-1 is a gravitationally lensed transient at z~3.3. If this interpretation is correct, the source is magnified by a factor of 4-7, and two counterimages are predicted. Our lens model predicts that there are time delays between the three images of 1-10 yr and that we have witnessed the final occurrence of the transient. The intense luminosity (MAB~-23.5 after correcting for lensing) and blue UV continuum (implying T>~50,000 K) argue that the source may have been a flare resulting from the tidal disruption of a star by a 106-108 Msolar black hole. Regardless of its physical nature, PALS-1 highlights the importance of monitoring regions of high magnification in galaxy clusters for distant time-varying phenomena. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the California Institute of Technology and the University of California.

  19. Probing the cosmic distance duality relation using time delay lenses

    Energy Technology Data Exchange (ETDEWEB)

    Rana, Akshay; Mahajan, Shobhit; Mukherjee, Amitabha [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Jain, Deepak [Deen Dayal Upadhyaya College, University of Delhi, Sector-3, Dwarka, New Delhi 110078 (India); Holanda, R.F.L., E-mail: montirana1992@gmail.com, E-mail: djain@ddu.du.ac.in, E-mail: shobhit.mahajan@gmail.com, E-mail: amimukh@gmail.com, E-mail: holanda@uepb.edu.br [Departamento de Física, Universidade Federal de Sergipe, 49100-000, Aracaju—SE (Brazil)

    2017-07-01

    The construction of the cosmic distance-duality relation (CDDR) has been widely studied. However, its consistency with various new observables remains a topic of interest. We present a new way to constrain the CDDR η( z ) using different dynamic and geometric properties of strong gravitational lenses (SGL) along with SNe Ia observations. We use a sample of 102 SGL with the measurement of corresponding velocity dispersion σ{sub 0} and Einstein radius θ {sub E} . In addition, we also use a dataset of 12 two image lensing systems containing the measure of time delay Δ t between source images. Jointly these two datasets give us the angular diameter distance D {sub A} {sub ol} of the lens. Further, for luminosity distance, we use the 740 observations from JLA compilation of SNe Ia. To study the combined behavior of these datasets we use a model independent method, Gaussian Process (GP). We also check the efficiency of GP by applying it on simulated datasets, which are generated in a phenomenological way by using realistic cosmological error bars. Finally, we conclude that the combined bounds from the SGL and SNe Ia observation do not favor any deviation of CDDR and are in concordance with the standard value (η=1) within 2σ confidence region, which further strengthens the theoretical acceptance of CDDR.

  20. Low-energy beam transport using space-charge lenses

    International Nuclear Information System (INIS)

    Meusel, O.; Bechtold, A.; Pozimski, J.; Ratzinger, U.; Schempp, A.; Klein, H.

    2005-01-01

    Space-charge lenses (SCL) of the Gabor type provide strong cylinder symmetric focusing for low-energy ion beams using a confined nonneutral plasma. They need modest magnetic and electrostatic field strength and provide a short installation length when compared to conventional LEBT-lenses like quadrupoles and magnetic solenoids. The density distribution of the enclosed space charge within the Gabor lens is given by the confinement in transverse and longitudinal directions. In the case of a positive ion beam, the space charge of the confined electron cloud may cause an overcompensation of the ion beam space-charge force and consequently focuses the beam. To investigate the capabilities of an SCL double-lens system for ion beam into an RFQ, a test injector was installed at IAP and put into operation successfully. Furthermore, to study the focusing capabilities of this lens at beam energies up to 500 keV, a high-field Gabor lens was built and installed downstream of the RFQ. Experimental results of the beam injection into the RFQ are presented as well as those of these first bunched beam-focusing tests with the 110 A keV He + beam

  1. IMPROVED CONSTRAINTS ON THE GRAVITATIONAL LENS Q0957+561. I. WEAK LENSING

    International Nuclear Information System (INIS)

    Nakajima, R.; Bernstein, G. M.; Fadely, R.; Keeton, C. R.; Schrabback, T.

    2009-01-01

    Attempts to constrain the Hubble constant using the strong gravitational lens system Q0957+561 are limited by systematic uncertainties in the mass model, since the time delay is known very precisely. One important systematic effect is the mass-sheet degeneracy, which arises because strong lens modeling cannot constrain the presence or absence of a uniform mass sheet κ, which rescales H 0 by the factor (1 - κ). In this paper, we present new constraints on the mass sheet derived from a weak-lensing analysis of the Hubble Space Telescope imaging of a 6 arcmin square region surrounding the lensed quasar. The average mass sheet within a circular aperture (the strong lens model region) is constrained by integrating the tangential weak gravitational shear over the surrounding area. We find the average convergence within a 30'' radius around the lens galaxy to be κ(<30'') = 0.166 ± 0.056 (1σ confidence level), normalized to the quasar redshift. This includes contributions from both the lens galaxy and the surrounding cluster. We also constrain a few other low-order terms in the lens potential by applying a multipole aperture mass formalism to the gravitational shear in an annulus around the strong-lensing region. Implications for strong lens models and the Hubble constant are discussed in an accompanying paper.

  2. A gravitationally lensed quasar discovered in OGLE

    Science.gov (United States)

    Kostrzewa-Rutkowska, Zuzanna; Kozłowski, Szymon; Lemon, Cameron; Anguita, T.; Greiner, J.; Auger, M. W.; Wyrzykowski, Ł.; Apostolovski, Y.; Bolmer, J.; Udalski, A.; Szymański, M. K.; Soszyński, I.; Poleski, R.; Pietrukowicz, P.; Skowron, J.; Mróz, P.; Ulaczyk, K.; Pawlak, M.

    2018-05-01

    We report the discovery of a new gravitationally lensed quasar (double) from the Optical Gravitational Lensing Experiment (OGLE) identified inside the ˜670deg2 area encompassing the Magellanic Clouds. The source was selected as one of ˜60 `red W1 - W2' mid-infrared objects from WISE and having a significant amount of variability in OGLE for both two (or more) nearby sources. This is the first detection of a gravitational lens, where the discovery is made `the other way around', meaning we first measured the time delay between the two lensed quasar images of -132 Technology Telescope spectra. The spectral energy distribution (SED) fitting with the fixed source redshift provided the estimate of the lensing galaxy redshift of z ≈ 0.9 ± 0.2 (90 per cent CL), while its type is more likely to be elliptical (the SED-inferred and lens-model stellar mass is more likely present in ellipticals) than spiral (preferred redshift by the lens model).

  3. Electron Lenses for the Large Hadron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Stancari, Giulio [Fermilab; Valishev, Alexander [Fermilab; Bruce, Roderik [CERN; Redaelli, Stefano [CERN; Rossi, Adriana [CERN; Salvachua, Belen [CERN

    2014-07-01

    Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-by-bunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beam compensation, and for the demonstration of halo scraping with hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in RHIC at BNL. Within the US LHC Accelerator Research Program and the European HiLumi LHC Design Study, hollow electron beam collimation was studied as an option to complement the collimation system for the LHC upgrades. This project is moving towards a technical design in 2014, with the goal to build the devices in 2015-2017, after resuming LHC operations and re-assessing needs and requirements at 6.5 TeV. Because of their electric charge and the absence of materials close to the proton beam, electron lenses may also provide an alternative to wires for long-range beam-beam compensation in LHC luminosity upgrade scenarios with small crossing angles.

  4. Weak lensing probes of modified gravity

    International Nuclear Information System (INIS)

    Schmidt, Fabian

    2008-01-01

    We study the effect of modifications to general relativity on large-scale weak lensing observables. In particular, we consider three modified gravity scenarios: f(R) gravity, the Dvali-Gabadadze-Porrati model, and tensor-vector-scalar theory. Weak lensing is sensitive to the growth of structure and the relation between matter and gravitational potentials, both of which will in general be affected by modified gravity. Restricting ourselves to linear scales, we compare the predictions for galaxy-shear and shear-shear correlations of each modified gravity cosmology to those of an effective dark energy cosmology with the same expansion history. In this way, the effects of modified gravity on the growth of perturbations are separated from the expansion history. We also propose a test which isolates the matter-potential relation from the growth factor and matter power spectrum. For all three modified gravity models, the predictions for galaxy and shear correlations will be discernible from those of dark energy with very high significance in future weak lensing surveys. Furthermore, each model predicts a measurably distinct scale dependence and redshift evolution of galaxy and shear correlations, which can be traced back to the physical foundations of each model. We show that the signal-to-noise for detecting signatures of modified gravity is much higher for weak lensing observables as compared to the integrated Sachs-Wolfe effect, measured via the galaxy-cosmic microwave background cross-correlation.

  5. Electron beams, lenses, and optics. Volume 2

    International Nuclear Information System (INIS)

    El-Kareh, A.B.; El-Kareh, J.C.J.

    1970-01-01

    This volume presents a systematic coverage of aberrations. It analyzes the geometrical aberrations and treats the spherical and chromatic aberrations in great detail. The coefficients of spherical and chromatic aberration have been computed for a series of electrostatic and magnetic lenses and are listed in table form. The book also covers space charge and its effect on highly focused electron beams

  6. Quantum Spin Lenses in Atomic Arrays

    Directory of Open Access Journals (Sweden)

    A. W. Glaetzle

    2017-09-01

    Full Text Available We propose and discuss quantum spin lenses, where quantum states of delocalized spin excitations in an atomic medium are focused in space in a coherent quantum process down to (essentially single atoms. These can be employed to create controlled interactions in a quantum light-matter interface, where photonic qubits stored in an atomic ensemble are mapped to a quantum register represented by single atoms. We propose Hamiltonians for quantum spin lenses as inhomogeneous spin models on lattices, which can be realized with Rydberg atoms in 1D, 2D, and 3D, and with strings of trapped ions. We discuss both linear and nonlinear quantum spin lenses: in a nonlinear lens, repulsive spin-spin interactions lead to focusing dynamics conditional to the number of spin excitations. This allows the mapping of quantum superpositions of delocalized spin excitations to superpositions of spatial spin patterns, which can be addressed by light fields and manipulated. Finally, we propose multifocal quantum spin lenses as a way to generate and distribute entanglement between distant atoms in an atomic lattice array.

  7. Software for Fermat's Principle and Lenses

    Science.gov (United States)

    Mihas, Pavlos

    2012-01-01

    Fermat's principle is considered as a unifying concept. It is usually presented erroneously as a "least time principle". In this paper we present some software that shows cases of maxima and minima and the application of Fermat's principle to the problem of focusing in lenses. (Contains 12 figures.)

  8. Studying dark matter haloes with weak lensing

    NARCIS (Netherlands)

    Velander, Malin Barbro Margareta

    2012-01-01

    Our Universe is comprised not only of normal matter but also of unknown components: dark matter and dark energy. This Thesis recounts studies of dark matter haloes, using a technique known as weak gravitational lensing, in order to learn more about the nature of these dark components. The haloes

  9. Tear exchange and contact lenses: a review.

    Science.gov (United States)

    Muntz, Alex; Subbaraman, Lakshman N; Sorbara, Luigina; Jones, Lyndon

    2015-01-01

    Tear exchange beneath a contact lens facilitates ongoing fluid replenishment between the ocular surface and the lens. This exchange is considerably lower during the wear of soft lenses compared with rigid lenses. As a result, the accumulation of tear film debris and metabolic by-products between the cornea and a soft contact lens increases, potentially leading to complications. Lens design innovations have been proposed, but no substantial improvement in soft lens tear exchange has been reported. Researchers have determined post-lens tear exchange using several methods, notably fluorophotometry. However, due to technological limitations, little remains known about tear hydrodynamics around the lens and, to-date, true tear exchange with contact lenses has not been shown. Further knowledge regarding tear exchange could be vital in aiding better contact lens design, with the prospect of alleviating certain adverse ocular responses. This article reviews the literature to-date on the significance, implications and measurement of tear exchange with contact lenses. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  10. Multiply imaged Transient Events in Cluster Lenses

    Science.gov (United States)

    Narasimha, Delampady

    2018-04-01

    ARIES had a successful gravitational microlens project during 1998-2002. A similar monitor for Transient Events in galaxies at high redshift lensed by rich galaxy-clusters provides a challenging possibility with important cosmological implications. Rich galaxy-clusters at intermediate redshifts are powerful gravitational lenses which produce multiple images, in the shape of giant arcs of 5-20" extent, of distant background galaxies in their field. Weak lens shear of the background galaxy distribution can reliably trace the lens mass profile. Multiple images of supernovae or GRBs in the background galaxies can be recorded in a systematic monitor of the system. An unlensed high redshift supernova might not be observable, but when lensed by a galaxy-cluster, it will stand out because the point event brightens relative to the host. The color profile of a high redshift lensed point event will be much more reliable than an unlensed one due to much less host contamination. An estimate of the time delay enables observation of the full light curve of the subsequent images of the event. ARIES can have outside collaboration for multiband simultaneous lightcurves of other images. The measured time delay and position of images of the transient event provide better cosmological constraints including distance scale of the Universe. The Devasthal telescope can detect one or more events by monitoring half a dozen cluster fields over three years time.

  11. Coatings and Tints of Spectacle Lenses

    Directory of Open Access Journals (Sweden)

    H. Zeki Büyükyıldız

    2012-10-01

    Full Text Available Spectacle lenses are made of mineral or organic (plastic materials. Various coatings and tints are applied to the spectacle lenses according to the characteristic of the lens material, and for the personal needs and cosmetic purpose. The coatings may be classified in seven groups: 1 Anti-reflection coatings, 2 Hard coatings, 3 Clean coat, 4 Mirror coatings, 5 Color tint coating (one of coloring processes, 6 Photochromic coating (one of photochromic processes, and 7 Anti-fog coatings. Anti-reflection coatings reduce unwanted reflections from the lens surfaces and increase light transmission. Hard coatings are applied for preventing the plastic lens surface from scratches and abrasion. Hard coatings are not required for the mineral lenses due to their hardness. Clean coat makes the lens surface smooth and hydrophobic. Thus, it prevents the adherence of dust, tarnish, and dirt particles on the lens surface. Mirror coatings are applied onto the sunglasses for cosmetic purpose. Color tinted and photochromic lenses are used for sun protection and absorption of the harmful UV radiations. Anti-fog coatings make the lens surface hydrophilic and prevent the coalescence of tiny water droplets on the lens surface that reduces light transmission. (Turk J Ophthalmol 2012; 42: 359-69

  12. Teaching the Theory of Real Lenses.

    Science.gov (United States)

    Walther, A.

    1996-01-01

    Presents an approach to the study of real lenses that would not contradict Fermat's principle. Shows how the rudiments of the correct theory can be incorporated into courses to provide students a clearer notion of what they can expect in laboratory situations. (DDR)

  13. Correlations in the three-dimensional Lyman-alpha forest contaminated by high column density absorbers

    Science.gov (United States)

    Rogers, Keir K.; Bird, Simeon; Peiris, Hiranya V.; Pontzen, Andrew; Font-Ribera, Andreu; Leistedt, Boris

    2018-05-01

    Correlations measured in three dimensions in the Lyman-alpha forest are contaminated by the presence of the damping wings of high column density (HCD) absorbing systems of neutral hydrogen (H I; having column densities N(H I) > 1.6 × 10^{17} atoms cm^{-2}), which extend significantly beyond the redshift-space location of the absorber. We measure this effect as a function of the column density of the HCD absorbers and redshift by measuring three-dimensional (3D) flux power spectra in cosmological hydrodynamical simulations from the Illustris project. Survey pipelines exclude regions containing the largest damping wings. We find that, even after this procedure, there is a scale-dependent correction to the 3D Lyman-alpha forest flux power spectrum from residual contamination. We model this residual using a simple physical model of the HCD absorbers as linearly biased tracers of the matter density distribution, convolved with their Voigt profiles and integrated over the column density distribution function. We recommend the use of this model over existing models used in data analysis, which approximate the damping wings as top-hats and so miss shape information in the extended wings. The simple `linear Voigt model' is statistically consistent with our simulation results for a mock residual contamination up to small scales (|k| account for the effect of the highest column density absorbers on the smallest scales (e.g. |k| > 0.4 h Mpc^{-1} for small damped Lyman-alpha absorbers; HCD absorbers with N(H I) ˜ 10^{21} atoms cm^{-2}). However, these systems are in any case preferentially removed from survey data. Our model is appropriate for an accurate analysis of the baryon acoustic oscillations feature. It is additionally essential for reconstructing the full shape of the 3D flux power spectrum.

  14. Are Disposable and Standard Gonioscopy Lenses Comparable?

    Science.gov (United States)

    Lee, Bonny; Szirth, Bernard C; Fechtner, Robert D; Khouri, Albert S

    2017-04-01

    Gonioscopy is important in the evaluation and treatment of glaucoma. With increased scrutiny of acceptable sterilization processes for health care instruments, disposable gonioscopy lenses have recently been introduced. Single-time use lenses are theorized to decrease infection risk and eliminate the issue of wear and tear seen on standard, reusable lenses. However, patient care would be compromised if the quality of images produced by the disposable lens were inferior to those produced by the reusable lens. The purpose of this study was to compare the quality of images produced by disposable versus standard gonioscopy lenses. A disposable single mirror lens (Sensor Medical Technology) and a standard Volk G-1 gonioscopy lens were used to image 21 volunteers who were prospectively recruited for the study. Images of the inferior and temporal angles of each subject's left eye were acquired using a slit-lamp camera through the disposable and standard gonioscopy lens. In total, 74 images were graded using the Spaeth gonioscopic system and for clarity and quality. Clarity was scored as 1 or 2 and defined as either (1) all structures perceived or (2) all structures not perceived. Quality was scored as 1, 2, or 3, and defined as (1) all angle landmarks clear and well focused, (2) some angle landmarks clear, others blurred, or (3) angle landmarks could not be ascertained. The 74 images were divided into images taken with the disposable single mirror lens and images taken with the standard Volk G-1 gonioscopy lens. The clarity and quality scores for each of these 2 image groups were averaged and P-values were calculated. Average quality of images produced with the standard lens was 1.46±0.56 compared with 1.54±0.61 for those produced with the disposable lens (P=0.55). Average clarity of images produced with the standard lens was 1.47±0.51 compared with 1.49±0.51 (P=0.90) with the disposable lens. We conclude that there is no significant difference in quality of images

  15. X-ray lenses with large aperture

    International Nuclear Information System (INIS)

    Simon, Markus

    2010-01-01

    Up to now, most X-ray imaging setups are based on absorption contrast imaging. There is a demand for focused X-rays in many X-ray analysis applications, either to increase the resolution of an imaging system, or, to reduce the time effort of an experiment through higher photon flux. For photon energies higher than 15 keV refractive X-ray optics are more efficient in comparison to non-refractive X-ray optics. The aim of this work was to develop X-ray lenses with large apertures and high transparency. By increasing the number of refracting surfaces while removing unnecessary lens material such lenses have been developed. Utilizing this approach the overall beam deflection angle is large with respect to the lens material it propagates through and so the transparency of the lens is increased. Within this work, X-ray lenses consisting of several thousands of prisms with an edge length in the range of micrometers have been developed and fabricated by deep X-ray lithography. Deep X-ray lithography enables high precision microstrucures with smooth sidewalls and large aspect ratios. The aperture of high-transparency X-ray lenses made this way is greater than 1 mm. They are suitable for photon energies in the range of 8 keV to 24 keV and offer a focal width of smaller than 10 μm at a transparency of around 40%. Furthermore, rolled X-ray lenses have been developed, that are made out of a microstructured polyimide film, which is cut according to the requirements regarding focal length and photon energy. The microstructured film is fabricated by molding, using an anisotropically etched silicon wafer as molding tool. Its mean roughness is in the range of nanometers. The film features prismatic structures, its surface topology is similar to an asparagus field. The measured diameter of the point focus was 18 μm to 31 μm, the calculated opticla efficiency was 37%. Future work will concentrate on increasing the aspect ratio of Prism Lenses and on increasing the rolling accuracy

  16. EFFECT OF HALO BIAS AND LYMAN LIMIT SYSTEMS ON THE HISTORY OF COSMIC REIONIZATION

    International Nuclear Information System (INIS)

    Kaurov, Alexander A.; Gnedin, Nickolay Y.

    2013-01-01

    We extend the existing analytical model of reionization by Furlanetto et al. to include the biasing of reionization sources and additional absorption by Lyman limit systems. Both effects enhance the original model in non-trivial ways, but do not change its qualitative features. Our model is, by construction, consistent with the observed evolution of the galaxy luminosity function at z ∼ 6 galaxies, the inadequacy of simulations and/or some of the observational constraints, or indicates an additional source of ionizing radiation at z > 8 remains to be seen.

  17. Natural and anthropogenic factors affecting freshwater lenses in coastal dunes of the Adriatic coast

    Science.gov (United States)

    Cozzolino, Davide; Greggio, Nicolas; Antonellini, Marco; Giambastiani, Beatrice Maria Sole

    2017-08-01

    This study characterizes the near-shore portion of the shallow coastal aquifer included in the Ravenna area (Northern Italy) with special attention to the roles of coastal dunes as freshwater reservoirs and their buffer on groundwater salinity. The paper focuses on the presence and evolution of freshwater lenses below coastal dunes and highlights the existing differences between preserved natural dunes and dunes strongly affected by human intervention. The influence that multiple natural and anthropogenic factors, such as land cover, local drainage network, and beach erosion have on the presence, size and evolution of the freshwater lenses in the aquifer is quantified and discussed. The methodology includes multiple seasonal monitoring and sampling campaigns of physical (water level, salinity, and temperature) and chemical (major cations and anions) groundwater parameters. Results indicate that freshwater lenses, where existing, are limited in thickness (about 1-2 m). Proximity to drainage ditches as well as limited dune elevation and size do not allow the formation and permanent storage of large freshwater lenses in the aquifer below the dunes. The pine forest land cover, that replaced the typical bush or sand cover, intensifies evapotranspiration reducing net infiltration and freshwater storage. The cation species distribution in the water shows that a freshening process is ongoing in preserved natural sites with stable or advancing beaches, whereas a salinization process is ongoing in anthropogenic-impacted areas with strongly-fragmented dune systems. Currently, the thin freshwater lenses in the shallow Ravenna coastal aquifer are limited in space and have no relevance for irrigation or any other human activity. The dune-beach system, however, is the recharge zone of the coastal aquifer and its protection is important to reduce water and soil salinization, which in turn control the health of the whole coastal ecosystem.

  18. Analysis of coronal H I Lyman alpha measurements from a rocket flight on 1979 April 13

    Science.gov (United States)

    Withbroe, G. L.; Kohl, J. L.; Weiser, H.; Noci, G.; Munro, R. H.

    1982-01-01

    It is noted that measurements of the profiles of resonantly scattered hydrogen Lyman-alpha coronal radiation have been used in determining hydrogen kinetic temperatures from 1.5 to 4 solar radii from sun center in a quiet region of the corona. Proton temperatures derived using the line widths decrease with height from 2.6 x 10 to the 6th K at 1.5 solar radii to 1.2 x 10 to the 6th K at 4 solar radii. These measurements, together with temperatures for lower heights determined from earlier Skylab and eclipse data, suggest that there is a maximum in the quiet coronal proton temperature at about 1.5 solar radii. Comparison of measured Lyman-alpha intensities with those calculated using a representative model for the radial variation of the coronal electron density yields information on the magnitude of the electron temperature gradient and suggests that the solar wind flow was subsonic for distances less than 4 solar radii.

  19. GALEX-SELECTED LYMAN BREAK GALAXIES AT z ∼ 2: COMPARISON WITH OTHER POPULATIONS

    International Nuclear Information System (INIS)

    Haberzettl, L.; Williger, G.; Lehnert, M. D.; Nesvadba, N.; Davies, L.

    2012-01-01

    We present results of a search for bright Lyman break galaxies (LBGs) at 1.5 ≤ z ≤ 2.5 in the GOODS-S field using an NUV-dropout technique in combination with color selection. We derived a sample of 73 LBG candidates. We compare our selection efficiencies to BM/BX and BzK methods (techniques solely based on ground-based data sets), and find the NUV data to provide greater efficiency for selecting star-forming galaxies. We estimate LBG candidate ages, masses, star formation rates, and extinction from fitting PEGASE synthesis evolution models. We find that about 20% of our LBG candidates are comparable to infrared-luminous LBGs or submillimeter galaxies which are thought to be precursors of massive elliptical galaxies today. Overall, we can show that although BM/BX and BzK methods do identify star-forming galaxies at z ∼ 2, the sample they provide biases against those star-forming galaxies which are more massive and contain sizeable red stellar populations. A true Lyman break criterion at z ∼ 2 is therefore more directly comparable to the populations found at z ∼ 3, which does contain a red fraction.

  20. Performance Characterization of the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) CCD Cameras

    Science.gov (United States)

    Joiner, R. K.; Kobayashi, K.; Winebarger, A. R.; Champey, P. R.

    2014-12-01

    The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a sounding rocket instrument which is currently being developed by NASA's Marshall Space Flight Center (MSFC) and the National Astronomical Observatory of Japan (NAOJ). The goal of this instrument is to observe and detect the Hanle effect in the scattered Lyman-Alpha UV (121.6nm) light emitted by the Sun's Chromosphere to make measurements of the magnetic field in this region. In order to make accurate measurements of this effect, the performance characteristics of the three on-board charge-coupled devices (CCDs) must meet certain requirements. These characteristics include: quantum efficiency, gain, dark current, noise, and linearity. Each of these must meet predetermined requirements in order to achieve satisfactory performance for the mission. The cameras must be able to operate with a gain of no greater than 2 e-/DN, a noise level less than 25e-, a dark current level which is less than 10e-/pixel/s, and a residual non-linearity of less than 1%. Determining these characteristics involves performing a series of tests with each of the cameras in a high vacuum environment. Here we present the methods and results of each of these performance tests for the CLASP flight cameras.

  1. Lyman-alpha clouds as a relic of primordial density fluctuations

    International Nuclear Information System (INIS)

    Bond, J.R.; Szalay, A.S.; Silk, J.

    1988-01-01

    Primordial density fluctuations are studied using a CDM model and primordial clouds some of which are expanding, driven by pressure gradients created when the medium is photionized, and some of which are massive enough to continue collapsing in spite of the pressure. Normalization of CDM models to the clustering properties on large scales are used to predict the parameters of collapsing clouds of subgalactic mass at early epochs. It is shown that the abundance and dimensions of these clouds are comparable to those of the Lyman-alpha systems. The evolutionary history of the clouds is computed, utilizing a spherically symmetric hydrodynamics code with the dark matter treated as a collisionless fluid, and the H I column density distribution is evaluated as a function of N(H I) and redshift. The observed cloud parameters come out naturally in the CDM model and suggest that Lyman-alpha clouds are the missing link between primordial density fluctuations and the formation of galaxies. 31 references

  2. GALEX-SELECTED LYMAN BREAK GALAXIES AT z {approx} 2: COMPARISON WITH OTHER POPULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Haberzettl, L.; Williger, G. [Department of Physics and Astronomy, University of Louisville, Louisville KY 20492 (United States); Lehnert, M. D. [GEPI, Observatoire de Paris, UMR 8111 du CNRS, 5 Place Jules Janssen, 92195 Meudon (France); Nesvadba, N. [Institut d' Astrophysique Spatiale, CNRS, Universite Paris-Sud, Bat. 120-121, 91405 Orsay (France); Davies, L. [Department of Physics, H H Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)

    2012-01-20

    We present results of a search for bright Lyman break galaxies (LBGs) at 1.5 {<=} z {<=} 2.5 in the GOODS-S field using an NUV-dropout technique in combination with color selection. We derived a sample of 73 LBG candidates. We compare our selection efficiencies to BM/BX and BzK methods (techniques solely based on ground-based data sets), and find the NUV data to provide greater efficiency for selecting star-forming galaxies. We estimate LBG candidate ages, masses, star formation rates, and extinction from fitting PEGASE synthesis evolution models. We find that about 20% of our LBG candidates are comparable to infrared-luminous LBGs or submillimeter galaxies which are thought to be precursors of massive elliptical galaxies today. Overall, we can show that although BM/BX and BzK methods do identify star-forming galaxies at z {approx} 2, the sample they provide biases against those star-forming galaxies which are more massive and contain sizeable red stellar populations. A true Lyman break criterion at z {approx} 2 is therefore more directly comparable to the populations found at z {approx} 3, which does contain a red fraction.

  3. Recovering the systemic redshift of galaxies from their Lyman-alpha line profile

    Science.gov (United States)

    Verhamme, A.; Garel, T.; Ventou, E.; Contini, T.; Bouché, N.; Herenz, E. C.; Richard, J.; Bacon, R.; Schmidt, K. B.; Maseda, M.; Marino, R. A.; Brinchmann, J.; Cantalupo, S.; Caruana, J.; Clément, B.; Diener, C.; Drake, A. B.; Hashimoto, T.; Inami, H.; Kerutt, J.; Kollatschny, W.; Leclercq, F.; Patrício, V.; Schaye, J.; Wisotzki, L.; Zabl, J.

    2018-04-01

    The Lyman alpha (Lyα) line of Hydrogen is a prominent feature in the spectra of star-forming galaxies, usually redshifted by a few hundreds of km s-1 compared to the systemic redshift. This large offset hampers follow-up surveys, galaxy pair statistics and correlations with quasar absorption lines when only Lyα is available. We propose diagnostics that can be used to recover the systemic redshift directly from the properties of the Lyα line profile. We use spectroscopic observations of Lyman-Alpha Emitters (LAEs) for which a precise measurement of the systemic redshift is available. Our sample contains 13 sources detected between z ≈ 3 and z ≈ 6 as part of various Multi Unit Spectroscopic Explorer (MUSE) Guaranteed Time Observations (GTO). We also include a compilation of spectroscopic Lyα data from the literature spanning a wide redshift range (z ≈ 0 - 8). First, restricting our analysis to double-peaked Lyα spectra, we find a tight correlation between the velocity offset of the red peak with respect to the systemic redshift, V_peak^red, and the separation of the peaks. Secondly, we find a correlation between V_peak^red and the full width at half maximum of the Lyα line. Fitting formulas, to estimate systemic redshifts of galaxies with an accuracy of ≤100 km s-1 when only the Lyα emission line is available, are given for the two methods.

  4. Analysis of coronal H I Lyman alpha measurements from a rocket flight on 1979 April 13

    International Nuclear Information System (INIS)

    Withbroe, G.L.; Kohl, J.L.; Weiser, H.; Noci, G.; Munro, R.H.

    1982-01-01

    Measurements of the profiles of resonantly scattered hydrogen Lyman-α coronal radiation have been used to determine hydrogen kinetic temperatures from 1.5 to 4 R/sub sun/ from Sun center in a quiet region of the corona. Proton temperatures derived from the line widths decrease with height from 2.6 x 10 6 K at r = 1.5 R/sub sun/ to 1.2 x 10 6 K at r = 4 R/sub sun/. These measurements combined with temperatures for lower heights determined from earlier Skylab and eclipse data suggest that there is a maximum in the quiet coronal proton temperature at about 1.5 R/sub sun/. Comparison of measured Lyman-α intensities with those calculated using a representative model for the radial variation of the coronal electron density provides information on the magnitude of the electron temperature gradient and suggests that the solar wind flow was subsonic for r<4 R/sub sun/ in the observed region. Comparison of the measured kinetic temperatures to the predictions of a simple two fluid model suggests that there is a small amount of proton heating and/or a nonthermal contribution to the motions of coronal protons between 1.5 and 4 R/sub sun/

  5. 3C 220.3: A radio galaxy lensing a submillimeter galaxy

    Energy Technology Data Exchange (ETDEWEB)

    Haas, Martin; Westhues, Christian; Chini, Rolf [Astronomisches Institut, Ruhr Universität, Bochum (Germany); Leipski, Christian; Klaas, Ulrich; Meisenheimer, Klaus [Max-Planck-Institut für Astronomie, Heidelberg (Germany); Barthel, Peter; Koopmans, Léon V. E. [Kapteyn Astronomical Institute, University of Groningen (Netherlands); Wilkes, Belinda J.; Bussmann, R. Shane; Willner, S. P.; Ashby, Matthew L. N.; Kuraszkiewicz, Joanna [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Vegetti, Simona [Max-Planck-Institut für Astrophysik, Garching (Germany); Clements, David L. [Imperial College, London (United Kingdom); Fassnacht, Christopher D. [University of California, Davis, CA (United States); Horesh, Assaf [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA (United States); Lagattuta, David J. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn (Australia); Stern, Daniel; Wylezalek, Dominika, E-mail: haas@astro.rub.de [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA (United States)

    2014-07-20

    Herschel Space Observatory photometry and extensive multiwavelength follow-up have revealed that the powerful radio galaxy (PRG) 3C 220.3 at z = 0.685 acts as a gravitational lens for a background submillimeter galaxy (SMG) at z = 2.221. At an observed wavelength of 1 mm, the SMG is lensed into three distinct images. In the observed near infrared, these images are connected by an arc of ∼1''.8 radius forming an Einstein half-ring centered near the radio galaxy. In visible light, only the arc is apparent. 3C 220.3 is the only known instance of strong galaxy-scale lensing by a PRG not located in a galaxy cluster and therefore it offers the potential to probe the dark matter content of the radio galaxy host. Lens modeling rejects a single lens, but two lenses centered on the radio galaxy host A and a companion B, separated by 1''.5, provide a fit consistent with all data and reveal faint candidates for the predicted fourth and fifth images. The model does not require an extended common dark matter halo, consistent with the absence of extended bright X-ray emission on our Chandra image. The projected dark matter fractions within the Einstein radii of A (1''.02) and B (0''.61) are about 0.4 ± 0.3 and 0.55 ± 0.3. The mass to i-band light ratios of A and B, M/L{sub i}∼8±4 M{sub ⊙} L{sub ⊙}{sup −1}, appear comparable to those of radio-quiet lensing galaxies at the same redshift in the CfA-Arizona Space Telescope LEns Survey, Lenses Structure and Dynamics, and Strong Lenses in the Legacy Survey samples. The lensed SMG is extremely bright with observed f(250 μm) = 440 mJy owing to a magnification factor μ ∼ 10. The SMG spectrum shows luminous, narrow C IV λ1549 Å emission, revealing that the SMG houses a hidden quasar in addition to a violent starburst. Multicolor image reconstruction of the SMG indicates a bipolar morphology of the emitted ultraviolet (UV) light suggestive of cones through which UV light escapes a

  6. KiDS-450: tomographic cross-correlation of galaxy shear with Planck lensing

    Science.gov (United States)

    Harnois-Déraps, Joachim; Tröster, Tilman; Chisari, Nora Elisa; Heymans, Catherine; van Waerbeke, Ludovic; Asgari, Marika; Bilicki, Maciej; Choi, Ami; Erben, Thomas; Hildebrandt, Hendrik; Hoekstra, Henk; Joudaki, Shahab; Kuijken, Konrad; Merten, Julian; Miller, Lance; Robertson, Naomi; Schneider, Peter; Viola, Massimo

    2017-10-01

    We present the tomographic cross-correlation between galaxy lensing measured in the Kilo Degree Survey (KiDS-450) with overlapping lensing measurements of the cosmic microwave background (CMB), as detected by Planck 2015. We compare our joint probe measurement to the theoretical expectation for a flat Λ cold dark matter cosmology, assuming the best-fitting cosmological parameters from the KiDS-450 cosmic shear and Planck CMB analyses. We find that our results are consistent within 1σ with the KiDS-450 cosmology, with an amplitude re-scaling parameter AKiDS = 0.86 ± 0.19. Adopting a Planck cosmology, we find our results are consistent within 2σ, with APlanck = 0.68 ± 0.15. We show that the agreement is improved in both cases when the contamination to the signal by intrinsic galaxy alignments is accounted for, increasing A by ∼0.1. This is the first tomographic analysis of the galaxy lensing - CMB lensing cross-correlation signal, and is based on five photometric redshift bins. We use this measurement as an independent validation of the multiplicative shear calibration and of the calibrated source redshift distribution at high redshifts. We find that constraints on these two quantities are strongly correlated when obtained from this technique, which should therefore not be considered as a stand-alone competitive calibration tool.

  7. Gravitational lensing and extra dimensions

    International Nuclear Information System (INIS)

    He, X-G.; University of Melbourne, Parkville, VIC; Joshi, G.C.; McKellar, B.H.J.

    1999-08-01

    We study gravitational tensing and the bending of light in low energy scale (M s ) gravity theories with extra space-time dimensions 'n'. We find that due to the presence of spin-2 Kaluza-Klein states from compactification, a correction to the deflection angle with a strong quadratic dependence on the photon energy is introduced. No deviation from the Einstein General Relativity prediction for the deflection angle for photons grazing the Sun in the visible band with 15% accuracy (90% c.l.) implies that the scale M s has to be larger than 1.4(2/(n-2)) 1/4 TeV and approximately 4 TeV for n=2. This lower bound is comparable with that from collider physics constraints. Gravitational tensing experiments with higher energy photons can provide stronger constraints. (authors)

  8. Plasma surface modification of rigid contact lenses decreases bacterial adhesion.

    Science.gov (United States)

    Wang, Yingming; Qian, Xuefeng; Zhang, Xiaofeng; Xia, Wei; Zhong, Lei; Sun, Zhengtai; Xia, Jing

    2013-11-01

    Contact lens safety is an important topic in clinical studies. Corneal infections usually occur because of the use of bacteria-carrying contact lenses. The current study investigated the impact of plasma surface modification on bacterial adherence to rigid contact lenses made of fluorosilicone acrylate materials. Boston XO and XO2 contact lenses were modified using plasma technology (XO-P and XO2-P groups). Untreated lenses were used as controls. Plasma-treated and control lenses were incubated in solutions containing Staphylococcus aureus or Pseudomonas aeruginosa. MTT colorimetry, colony-forming unit counting method, and scanning electron microscopy were used to measure bacterial adhesion. MTT colorimetry measurements showed that the optical density (OD) values of XO-P and XO2-P were significantly lower than those of XO and XO2, respectively, after incubation with S. aureus (P lenses and to the XO2-P versus XO2 lenses incubated with S. aureus (P lenses incubated with P. aeruginosa (P lenses. Plasma surface modification can significantly decrease bacterial adhesion to fluorosilicone acrylate contact lenses. This study provides important evidence of a unique benefit of plasma technology in contact lens surface modification.

  9. A new case of gravitational lensing

    International Nuclear Information System (INIS)

    Surdej, J.; Swings, J.-P.; Borgeest, U.; Kayser, R.; Refsdal, S.; Courvoisier, T.J.-L.; Kellermann, K.I.; Kuehr, H.

    1987-01-01

    The authors report a brief description of a gravitational lens system UM673 = Q0142 - 100 = PHL3703. It consists of two images, A and B, separated by 2.2 arc s at a redshift zsub(q) = 2.719. The lensing galaxy has also been found. It lies very near the line connecting the two QSO (quasi-stellar objects) images, approx. 0.8 arc s from the fainter one. Application of gravitational optometry to this system leads to a value Msub(o) or approx. = 2.4 x 10 11 M solar masses for the mass of the lensing galaxy and to Δt approx. 7 weeks for the most likely travel-time difference between the two light paths to the QSO. (author)

  10. Nulling tomography with weak gravitational lensing

    International Nuclear Information System (INIS)

    Huterer, Dragan; White, Martin

    2005-01-01

    We explore several strategies of eliminating (or nulling) the small-scale information in weak lensing convergence power spectrum measurements in order to protect against undesirable effects, for example, the effects of baryonic cooling and pressure forces on the distribution of large-scale structures. We selectively throw out the small-scale information in the convergence power spectrum that is most sensitive to the unwanted bias, while trying to retain most of the sensitivity to cosmological parameters. The strategies are effective in the difficult but realistic situations when we are able to guess the form of the contaminating effect only approximately. However, we also find that the simplest scheme of simply not using information from the largest multipoles works about as well as the proposed techniques in most, although not all, realistic cases. We advocate further exploration of nulling techniques and believe that they will find important applications in the weak lensing data mining

  11. Poisson equation for weak gravitational lensing

    International Nuclear Information System (INIS)

    Kling, Thomas P.; Campbell, Bryan

    2008-01-01

    Using the Newman and Penrose [E. T. Newman and R. Penrose, J. Math. Phys. (N.Y.) 3, 566 (1962).] spin-coefficient formalism, we examine the full Bianchi identities of general relativity in the context of gravitational lensing, where the matter and space-time curvature are projected into a lens plane perpendicular to the line of sight. From one component of the Bianchi identity, we provide a rigorous, new derivation of a Poisson equation for the projected matter density where the source term involves second derivatives of the observed weak gravitational lensing shear. We also show that the other components of the Bianchi identity reveal no new results. Numerical integration of the Poisson equation in test cases shows an accurate mass map can be constructed from the combination of a ground-based, wide-field image and a Hubble Space Telescope image of the same system

  12. Astrophysical observations: lensing and eclipsing Einstein's theories.

    Science.gov (United States)

    Bennett, Charles L

    2005-02-11

    Albert Einstein postulated the equivalence of energy and mass, developed the theory of special relativity, explained the photoelectric effect, and described Brownian motion in five papers, all published in 1905, 100 years ago. With these papers, Einstein provided the framework for understanding modern astrophysical phenomena. Conversely, astrophysical observations provide one of the most effective means for testing Einstein's theories. Here, I review astrophysical advances precipitated by Einstein's insights, including gravitational redshifts, gravitational lensing, gravitational waves, the Lense-Thirring effect, and modern cosmology. A complete understanding of cosmology, from the earliest moments to the ultimate fate of the universe, will require developments in physics beyond Einstein, to a unified theory of gravity and quantum physics.

  13. Calibration of fisheye lenses for hemispherical photography

    International Nuclear Information System (INIS)

    Diaci, J.; Kolar, U.

    2000-01-01

    Hemispherical photography represents one of the most appropriate methods of estimating averages of solar radiation over extended periods of time. This method is based upon the use of extremely wide-angle fisheye lenses, which produce large projection distortion. To correctly interpret hemispherical photography we have to know the projection characteristics of the fisheye lens in combination with a camera body. This can be achieved through lens calibration. The first part of the article explains in detail the calibration method for fisheye lenses which are used to assess the solar radiation in forest ecology research. In the second part the results of calibration for fisheye lens Sigma 8 mm, f/4 (MF, N) are presented. The lens was used on a Nikon F50 camera body

  14. Antifouling leaching technique for optical lenses

    Science.gov (United States)

    Strahle, William J.; Perez, C. L.; Martini, Marinna A.

    1994-01-01

    The effectiveness of optical lenses deployed in water less than 100 m deep is significantly reduced by biofouling caused by the settlement of macrofauna, such as barnacles, hydroids, and tunicates. However, machineable porous plastic rings can be used to dispense antifoulant into the water in front of the lens to retard macrofaunal growth without obstructing the light path. Unlike coatings which can degrade the optical performance, antifouling rings do not interfere with the instrument optics. The authors have designed plastic, reusable cup-like antifouling rings to slip over the optical lenses of a transmissometer. These rings have been used for several deployments on shallow moorings in Massachusetts Bay, MA and have increased the time before fouling degrades optical characteristics

  15. SPECTROSCOPIC OBSERVATIONS OF LYMAN BREAK GALAXIES AT REDSHIFTS ∼4, 5, AND 6 IN THE GOODS-SOUTH FIELD

    International Nuclear Information System (INIS)

    Vanzella, E.; Cristiani, S.; Nonino, M.; Giavalisco, M.; Dickinson, M.; Kuntschner, H.; Fosbury, R. A. E.; Popesso, P.; Rosati, P.; Cesarsky, C.; Renzini, A.; Stern, D.; Ferguson, H. C.

    2009-01-01

    We report on observations of Lyman break galaxies (LBGs) selected from the Great Observatories Origins Deep Survey at mean redshifts z ∼ 4, 5, and 6 (B 435 -, V 606 -, and i 775 -band dropouts, respectively), obtained with the red-sensitive FORS2 spectrograph at the ESO VLT. This program has yielded spectroscopic identifications for 114 galaxies (∼60% of the targeted sample), of which 51 are at z ∼ 4, 31 at z ∼ 5, and 32 at z ∼ 6. We demonstrate that the adopted selection criteria are effective, identifying galaxies at the expected redshift with minimal foreground contamination. Of the 10% interlopers, 83% turn out to be Galactic stars. Once selection effects are properly accounted for, the rest-frame ultraviolet (UV) spectra of the higher redshift LBGs appear to be similar to their counterparts at z ∼ 3. As at z ∼ 3, LBGs at z ∼ 4 and z ∼ 5 are observed with Lyα both in emission and in absorption; when in absorption, strong interstellar lines are also observed in the spectra. The stacked spectra of Lyα absorbers and emitters also show that the former have redder UV spectra and stronger but narrower interstellar lines, a fact also observed at z ∼ 2 and 3. At z ∼ 6, sensitivity issues bias our sample toward galaxies with Lyα in emission; nevertheless, these spectra appear to be similar to their lower redshift counterparts. As in other studies at similar redshifts, we find clear evidence that brighter LBGs tend to have weaker Lyα emission lines. At fixed rest-frame UV luminosity, the equivalent width of the Lyα emission line is larger at higher redshifts. At all redshifts where the measurements can be reliably made, the redshift of the Lyα emission line turns out to be larger than that of the interstellar absorption lines (ISLs), with a median velocity difference ΔV ∼ 400 km s -1 at z ∼ 4 and 5, consistent with results at lower redshifts. This shows that powerful, large-scale winds are common at high redshift. In general, there is no

  16. Microbial adhesion to silicone hydrogel lenses: a review.

    Science.gov (United States)

    Willcox, Mark D P

    2013-01-01

    Microbial adhesion to contact lenses is believed to be one of the initiating events in the formation of many corneal infiltrative events, including microbial keratitis, that occur during contact lens wear. The advent of silicone hydrogel lenses has not reduced the incidence of these events. This may partly be related to the ability of microbes to adhere to these lenses. The aim of this study was to review the published literature on microbial adhesion to contact lenses, focusing on adhesion to silicone hydrogel lenses. The literature on microbial adhesion to contact lenses was searched, along with associated literature on adverse events that occur during contact lens wear. Particular reference was paid to the years 1995 through 2012 because this encompasses the time when the first clinical trials of silicone hydrogel lenses were reported, and their commercial availability and the publication of epidemiology studies on adverse events were studied. In vitro studies of bacterial adhesion to unworn silicone hydrogel lens have shown that generally, bacteria adhere to these lenses in greater numbers than to the hydroxyethyl methacrylate-based soft lenses. Lens wear has different effects on microbial adhesion, and this is dependent on the type of lens and microbial species/genera that is studied. Biofilms that can be formed on any lens type tend to protect the bacteria and fungi from the effects on disinfectants. Fungal hyphae can penetrate the surface of most types of lenses. Acanthamoeba adhere in greater numbers to first-generation silicone hydrogel lenses compared with the second-generation or hydroxyethyl methacrylate-based soft lenses. Microbial adhesion to silicone hydrogel lenses occurs and is associated with the production of corneal infiltrative events during lens wear.

  17. Automatic centring and bonding of lenses

    Science.gov (United States)

    Krey, Stefan; Heinisch, J.; Dumitrescu, E.

    2007-05-01

    We present an automatic bonding station which is able to center and bond individual lenses or doublets to a barrel with sub micron centring accuracy. The complete manufacturing cycle includes the glue dispensing and UV curing. During the process the state of centring is continuously controlled by the vision software, and the final result is recorded to a file for process statistics. Simple pass or fail results are displayed to the operator at the end of the process.

  18. Gravitational lensing in metric theories of gravity

    International Nuclear Information System (INIS)

    Sereno, Mauro

    2003-01-01

    Gravitational lensing in metric theories of gravity is discussed. I introduce a generalized approximate metric element, inclusive of both post-post-Newtonian contributions and a gravitomagnetic field. Following Fermat's principle and standard hypotheses, I derive the time delay function and deflection angle caused by an isolated mass distribution. Several astrophysical systems are considered. In most of the cases, the gravitomagnetic correction offers the best perspectives for an observational detection. Actual measurements distinguish only marginally different metric theories from each other

  19. Twenty years of research on fungal-plant interactions on Lyman Glacier forefront—lessons learned and questions yet unanswered

    Science.gov (United States)

    Ari Jumpponen; Shawn P. Brown; James M. Trappe; Efrén Cázares; Rauni. Strömmer

    2012-01-01

    Retreating glaciers and the periglacial areas that they vacate produce a harsh environment of extreme radiation, nutrient limitations and temperature oscillations. They provide a model system for studying mechanisms that drive the establishment and early assembly of communities. Here, we synthesize more than 20 years of research at the Lyman Glacier forefront in the...

  20. Generation of continuous coherent radiation at Lyman-alpha and 1S-2P Spectroscopy of atomic hydrogen

    NARCIS (Netherlands)

    Pahl, A.; Fendel, P.; Henrich, B.R.; Walz, J.; Hansch, T.W.; Eikema, K.S.E.

    2005-01-01

    Continuous coherent radiation from wavelengths from 121 to 123 nm in the vacuum ultraviolet (VUV) was generated by four-wave sum-frequency mixing in mercury vapor. A yield of 20 nW at Lyman-alpha (121.57 nm) was achieved. We describe the experimental setup in detail and present a calculation of the

  1. Comparison of Lyman-alpha and LI-COR infrared hygrometers for airborne measurement of turbulent fluctuations of water vapour

    Science.gov (United States)

    Lampert, Astrid; Hartmann, Jörg; Pätzold, Falk; Lobitz, Lennart; Hecker, Peter; Kohnert, Katrin; Larmanou, Eric; Serafimovich, Andrei; Sachs, Torsten

    2018-05-01

    To investigate if the LI-COR humidity sensor can be used as a replacement of the Lyman-alpha sensor for airborne applications, the measurement data of the Lyman-alpha and several LI-COR sensors are analysed in direct intercomparison flights on different airborne platforms. One vibration isolated closed-path and two non-isolated open-path LI-COR sensors were installed on a Dornier 128 twin engine turbo-prop aircraft. The closed-path sensor provided absolute values and fluctuations of the water vapour mixing ratio in good agreement with the Lyman-alpha. The signals of the two open-path sensors showed considerable high-frequency noise, and the absolute value of the mixing ratio was observed to drift with time in this vibrational environment. On the helicopter-towed sensor system Helipod, with very low vibration levels, the open-path LI-COR sensor agreed very well with the Lyman-alpha sensor over the entire frequency range up to 3 Hz. The results show that the LI-COR sensors are well suited for airborne measurements of humidity fluctuations, provided that a vibrationless environment is given, and this turns out to be more important than close sensor spacing.

  2. Automation Enhancement of Multilayer Laue Lenses

    Energy Technology Data Exchange (ETDEWEB)

    Lauer K. R.; Conley R.

    2010-12-01

    X-ray optics fabrication at Brookhaven National Laboratory has been facilitated by a new, state of the art magnetron sputtering physical deposition system. With its nine magnetron sputtering cathodes and substrate carrier that moves on a linear rail via a UHV brushless linear servo motor, the system is capable of accurately depositing the many thousands of layers necessary for multilayer Laue lenses. I have engineered a versatile and automated control program from scratch for the base system and many subsystems. Its main features include a custom scripting language, a fully customizable graphical user interface, wireless and remote control, and a terminal-based interface. This control system has already been successfully used in the creation of many types of x-ray optics, including several thousand layer multilayer Laue lenses.Before reaching the point at which a deposition can be run, stencil-like masks for the sputtering cathodes must be created to ensure the proper distribution of sputtered atoms. Quality of multilayer Laue lenses can also be difficult to measure, given the size of the thin film layers. I employ my knowledge of software and algorithms to further ease these previously painstaking processes with custom programs. Additionally, I will give an overview of an x-ray optic simulator package I helped develop during the summer of 2010. In the interest of keeping my software free and open, I have worked mostly with the multiplatform Python and the PyQt application framework, utilizing C and C++ where necessary.

  3. Gravitational lensing of the SNLS supernovae

    International Nuclear Information System (INIS)

    Kronborg, T.

    2011-01-01

    Type Ia supernovae have become an essential tool of modern observational cosmology. By studying the distance-redshift relation of a large number of supernovae, the nature of dark energy can be unveiled. Distances to Type Ia SNe are however affected by gravitational lensing which can induce systematic effects in the measurement of cosmology. The majority of the supernovae is slightly de-magnified whereas a small fraction is significantly magnified due to the mass distribution along the line of sight. This causes naturally an additional dispersion in the observed magnitudes. There are two different ways to estimate the magnification of a supernova. A first method consists in comparing the supernova luminosity, which is measured to about 15% precision, to the mean SN luminosity at the same redshift. Another estimate can be obtained from predicting the magnification induced by the foreground matter density modeled from the measurements of the luminosity of the galaxies with an initial prior on the mass-luminosity relation of the galaxies. A correlation between these 2 estimates will make it possible to tune the initially used mass-luminosity relation resulting in an independent measurement of the dark matter clustering based on the luminosity of SNe Ia. Evidently, this measurement depends crucially on the detection of this correlation also referred to as the lensing signal. This thesis is dedicated to the measurement of the lensing signal in the SNLS 3-year sample. (author)

  4. Primordial black holes survive SN lensing constraints

    Science.gov (United States)

    García-Bellido, Juan; Clesse, Sébastien; Fleury, Pierre

    2018-06-01

    It has been claimed in [arxiv:1712.02240] that massive primordial black holes (PBH) cannot constitute all of the dark matter (DM), because their gravitational-lensing imprint on the Hubble diagram of type Ia supernovae (SN) would be incompatible with present observations. In this note, we critically review those constraints and find several caveats on the analysis. First of all, the constraints on the fraction α of PBH in matter seem to be driven by a very restrictive choice of priors on the cosmological parameters. In particular, the degeneracy between Ωm and α was ignored and thus, by fixing Ωm, transferred the constraining power of SN magnitudes to α. Furthermore, by considering more realistic physical sizes for the type-Ia supernovae, we find an effect on the SN lensing magnification distribution that leads to significantly looser constraints. Moreover, considering a wide mass spectrum of PBH, such as a lognormal distribution, further softens the constraints from SN lensing. Finally, we find that the fraction of PBH that could constitute DM today is bounded by fPBH < 1 . 09(1 . 38) , for JLA (Union 2.1) catalogs, and thus it is perfectly compatible with an all-PBH dark matter scenario in the LIGO band.

  5. Electron lenses for the large hadron collider

    CERN Document Server

    Stancari†, G; Bruce, R; Redaelli, S; Rossi, A; Salvachua Ferrando, B

    2014-01-01

    Electron lenses are pulsed, magnetically confined electron beamswhose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-bybunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beamcompensation, and for the demonstration of halo scrapingwith hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in RHIC at BNL. Within the US LHC Accelerator Research Program and the European HiLumi LHC Design Study, hollow electron beam collimation was studied as an option to complement the collimation system for the LHC upgrades. A conceptual design was recently completed, and the project is moving towards a technical design in 2014–2015 for construction in 2015–2017, if needed, after resuming LHC operations and re-assessing collimation needs and requirements at 6.5 TeV. Because of the...

  6. ABSORPTION-LINE SPECTROSCOPY OF GRAVITATIONALLY LENSED GALAXIES: FURTHER CONSTRAINTS ON THE ESCAPE FRACTION OF IONIZING PHOTONS AT HIGH REDSHIFT

    Energy Technology Data Exchange (ETDEWEB)

    Leethochawalit, Nicha; Ellis, Richard S.; Zitrin, Adi [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Jones, Tucker A. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Stark, Daniel P. [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States)

    2016-11-10

    The fraction of ionizing photons escaping from high-redshift star-forming galaxies is a key obstacle in evaluating whether galaxies were the primary agents of cosmic reionization. We previously proposed using the covering fraction of low-ionization gas, measured via deep absorption-line spectroscopy, as a proxy. We now present a significant update, sampling seven gravitationally lensed sources at 4 < z < 5. We show that the absorbing gas in our sources is spatially inhomogeneous, with a median covering fraction of 66%. Correcting for reddening according to a dust-in-cloud model, this implies an estimated absolute escape fraction of ≃19% ± 6%. With possible biases and uncertainties, collectively we find that the average escape fraction could be reduced to no less than 11%, excluding the effect of spatial variations. For one of our lensed sources, we have sufficient signal-to-noise ratio to demonstrate the presence of such spatial variations and scatter in its dependence on the Ly α equivalent width, consistent with recent simulations. If this source is typical, our lower limit to the escape fraction could be reduced by a further factor ≃2. Across our sample, we find a modest anticorrelation between the inferred escape fraction and the local star formation rate, consistent with a time delay between a burst and leaking Lyman continuum photons. Our analysis demonstrates considerable variations in the escape fraction, consistent with being governed by the small-scale behavior of star-forming regions, whose activities fluctuate over short timescales. This supports the suggestion that the escape fraction may increase toward the reionization era when star formation becomes more energetic and burst-like.

  7. Chitah: Strong-gravitational-lens hunter in imaging surveys

    Energy Technology Data Exchange (ETDEWEB)

    Chan, James H. H.; Suyu, Sherry H.; Chiueh, Tzihong; More, Anupreeta; Marshall, Philip J.; Coupon, Jean; Oguri, Masamune; Price, Paul

    2015-07-07

    Strong gravitationally lensed quasars provide powerful means to study galaxy evolution and cosmology. Current and upcoming imaging surveys will contain thousands of new lensed quasars, augmenting the existing sample by at least two orders of magnitude. To find such lens systems, we built a robot, Chitah, that hunts for lensed quasars by modeling the configuration of the multiple quasar images. Specifically, given an image of an object that might be a lensed quasar, Chitah first disentangles the light from the supposed lens galaxy and the light from the multiple quasar images based on color information. A simple rule is designed to categorize the given object as a potential four-image (quad) or two-image (double) lensed quasar system. The configuration of the identified quasar images is subsequently modeled to classify whether the object is a lensed quasar system. We test the performance of Chitah using simulated lens systems based on the Canada–France–Hawaii Telescope Legacy Survey. For bright quads with large image separations (with Einstein radius ${r}_{\\mathrm{ein}}\\gt 1\\buildrel{\\prime\\prime}\\over{.} 1$) simulated using Gaussian point-spread functions, a high true-positive rate (TPR) of $\\sim 90\\%$ and a low false-positive rate of $\\sim 3\\%$ show that this is a promising approach to search for new lens systems. We obtain high TPR for lens systems with ${r}_{\\mathrm{ein}}\\gtrsim 0\\buildrel{\\prime\\prime}\\over{.} 5$, so the performance of Chitah is set by the seeing. We further feed a known gravitational lens system, COSMOS 5921+0638, to Chitah, and demonstrate that Chitah is able to classify this real gravitational lens system successfully. Our newly built Chitah is omnivorous and can hunt in any ground-based imaging surveys.

  8. Galaxy–Galaxy Weak-lensing Measurements from SDSS. I. Image Processing and Lensing Signals

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Wentao [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Nandan Road 80, Shanghai 200030 (China); Yang, Xiaohu; Zhang, Jun; Tweed, Dylan [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Fu, Liping; Shu, Chenggang [Shanghai Key Lab for Astrophysics, Shanghai Normal University, 100 Guilin Road, 200234, Shanghai (China); Mo, H. J. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305 (United States); Bosch, Frank C. van den [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Li, Ran [Key Laboratory for Computational Astrophysics, Partner Group of the Max Planck Institute for Astrophysics, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 (China); Li, Nan [Department of Astronomy and Astrophysics, The University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Liu, Xiangkun; Pan, Chuzhong [Department of Astronomy, Peking University, Beijing 100871 (China); Wang, Yiran [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana, IL 61801 (United States); Radovich, Mario, E-mail: walt@shao.ac.cn, E-mail: xyang@sjtu.edu.cn [INAF-Osservatorio Astronomico di Napoli, via Moiariello 16, I-80131 Napoli (Italy)

    2017-02-10

    We present our image processing pipeline that corrects the systematics introduced by the point-spread function (PSF). Using this pipeline, we processed Sloan Digital Sky Survey (SDSS) DR7 imaging data in r band and generated a galaxy catalog containing the shape information. Based on our shape measurements of the galaxy images from SDSS DR7, we extract the galaxy–galaxy (GG) lensing signals around foreground spectroscopic galaxies binned in different luminosities and stellar masses. We estimated the systematics, e.g., selection bias, PSF reconstruction bias, PSF dilution bias, shear responsivity bias, and noise rectification bias, which in total is between −9.1% and 20.8% at 2 σ levels. The overall GG lensing signals we measured are in good agreement with Mandelbaum et al. The reduced χ {sup 2} between the two measurements in different luminosity bins are from 0.43 to 0.83. Larger reduced χ {sup 2} from 0.60 to 1.87 are seen for different stellar mass bins, which is mainly caused by the different stellar mass estimator. The results in this paper with higher signal-to-noise ratio are due to the larger survey area than SDSS DR4, confirming that more luminous/massive galaxies bear stronger GG lensing signals. We divide the foreground galaxies into red/blue and star-forming/quenched subsamples and measure their GG lensing signals. We find that, at a specific stellar mass/luminosity, the red/quenched galaxies have stronger GG lensing signals than their counterparts, especially at large radii. These GG lensing signals can be used to probe the galaxy–halo mass relations and their environmental dependences in the halo occupation or conditional luminosity function framework.

  9. Intraocular pressure measurement with the noncontact tonometer through soft contact lenses.

    Science.gov (United States)

    Liu, Yi-Chun; Huang, Jehn-Yu; Wang, I-Jong; Hu, Fung-Rong; Hou, Yu-Chih

    2011-03-01

    To assess the accuracy of measuring intraocular pressure (IOP) through a soft contact lens (SCL) with different refractive powers using a noncontact tonometer (NCT). Thirty-two healthy adult volunteers free of glaucoma or corneal disease participated in this study. IOP was measured in the right eyes without SCLs and with different lens powers, from -3.0 to -12.0 D as measured by NCT. IOP of the left eyes was also measured, as an internal control. Corneal curvature was measured in both eyes using an autokeratometer. Sixteen volunteers wore one brand of SCL (group A) and the other 16 wore a different brand, with 2 different curvatures (groups B and C). Statistical data were analyzed by SPSS using the Wilcoxon signed rank test for comparison of IOP readings and multiple linear regression analysis for the relationship among power of contact lenses, corneal power, and difference in IOP measurements. The difference in mean IOP between eyes without lenses and those with lenses was statistically significant in lens with -6.0 D and below in all 3 groups. The decrease in IOP significantly correlated with the refractive power of contact lenses in all 3 groups. The difference in IOP measurements was influenced by the mean K in group A but not in group B or C. There was no statistically significant difference in the IOP measurements in the left eyes or in the mean K between the right and left eyes. IOP measurement through myopic SCLs by NCT may be inaccurate and tends toward underestimation, especially in high myopic lenses. A strong relationship exists between IOP reduction and myopic lens power.

  10. [IOP measurement through frequent-replacement soft contact lenses].

    Science.gov (United States)

    Touboul, J

    2008-07-01

    Intraocular pressure (IOP) can be measured through soft contact lenses with an air-puff tonometer. These measurements seemed accurate for low-power negative lenses. For positive soft contact lenses, IOP is overestimated. The measurement of IOP through a soft contact lens is acceptable in clinical practice only for glaucoma screening. In glaucomatous patients or patients with ocular hypertension, IOP measurements should be performed without a contact lens. The main technique for IOP measurement remains Goldmann applanation tonometry.

  11. Do swimming goggles limit microbial contamination of contact lenses?

    Science.gov (United States)

    Wu, Yvonne T; Tran, Jess; Truong, Michelle; Harmis, Najat; Zhu, Hua; Stapleton, Fiona

    2011-04-01

    Wearing goggles over contact lenses while swimming is often recommended by eye care professionals. Limited data are available to assess this recommendation. The purpose of this study was to examine whether wearing goggles while swimming limits bacterial colonization on contact lenses and whether the type of lens worn affects contamination rates. Twenty-three subjects underwent two swimming sessions at an ocean (salt water) pool (Maroubra beach Rock Pool, Sydney, Australia). Silicone hydrogel (Ciba Focus Night and Day) or hydrogel lenses (Ciba Focus Daily) were inserted into subjects' eyes before 30 min of swimming sessions, and subjects used modified goggles to mimic goggled and non-goggled conditions. At the end of each session, lenses were collected for microbial investigation. Viable bacterial colonies were classified as gram positive and gram negative and enumerated. The level of bacterial colonization on contact lenses between goggled and non-goggled conditions and between the two lens materials were compared. The range of colony forming units recovered from goggled lenses were 0 to 930 compared with 0 to 1210 on non-goggled lenses. The majority of subjects (16/23) had more microorganisms in the non-goggled condition than when wearing goggles (p = 0.03). Gram negative organisms were found in three non-goggled lenses. No significant difference was shown in the number of bacteria isolated from silicone hydrogel and hydrogel lenses (p > 0.6) irrespective of wearing goggles. Water samples had consistently higher numbers of bacterial counts than those adhered to the lenses; however, no association was found between the number of bacteria in the water sample and those found on the contact lenses. Consistently, fewer bacterial colonies were found on the goggled contact lens, thus suggesting goggles offer some protection against bacterial colonization of contact lenses while swimming. These data would support the recommendation encouraging lens wearers to use goggles

  12. Plasma lenses for SLAC Final Focus Test facility

    International Nuclear Information System (INIS)

    Betz, D.; Cline, D.; Joshi, C.; Rajagopalan, S.; Rosenzweig, J.; Su, J.J.; Williams, R.; Chen, P.; Gundersen, M.; Katsouleas, T.; Norem, J.

    1991-01-01

    A collaborative group of accelerator and plasma physicists and engineers has formed with an interest in exploring the use of plasma lenses to meet the needs of future colliders. Analytic and computational models of plasma lenses are briefly reviewed and several design examples for the SLAC Final Focus Test Beam are presented. The examples include discrete, thick, and adiabatic lenses. A potential plasma source with desirable lens characteristics is presented

  13. Corrections for gravitational lensing of supernovae: better than average?

    OpenAIRE

    Gunnarsson, Christofer; Dahlen, Tomas; Goobar, Ariel; Jonsson, Jakob; Mortsell, Edvard

    2005-01-01

    We investigate the possibility of correcting for the magnification due to gravitational lensing of standard candle sources, such as Type Ia supernovae. Our method uses the observed properties of the foreground galaxies along the lines-of-sight to each source and the accuracy of the lensing correction depends on the quality and depth of these observations as well as the uncertainties in translating the observed luminosities to the matter distribution in the lensing galaxies. The current work i...

  14. Mechanism and computational model for Lyman-α-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas

    Science.gov (United States)

    Louchev, Oleg A.; Bakule, Pavel; Saito, Norihito; Wada, Satoshi; Yokoyama, Koji; Ishida, Katsuhiko; Iwasaki, Masahiko

    2011-09-01

    We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-α (Ly-α) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-α generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-α radiation generation can achieve a value of ˜5×10-4 which is restricted by the total combined absorption of the fundamental and generated radiation.

  15. Mechanism and computational model for Lyman-{alpha}-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas

    Energy Technology Data Exchange (ETDEWEB)

    Louchev, Oleg A.; Saito, Norihito; Wada, Satoshi [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Bakule, Pavel [STFC, ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX (United Kingdom); Yokoyama, Koji [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Ishida, Katsuhiko; Iwasaki, Masahiko [Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan)

    2011-09-15

    We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-{alpha} (Ly-{alpha}) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-{alpha} generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-{alpha} radiation generation can achieve a value of {approx}5x10{sup -4} which is restricted by the total combined absorption of the fundamental and generated radiation.

  16. Three-dimensional quadrupole lenses made with permanent magnets

    International Nuclear Information System (INIS)

    Ivanov, A.S.

    1984-01-01

    The performance of accelerator systems with quadrupole magnets can be improved by using permanent magnets in quadrupole lenses. This requires better methods for treating the three-dimensional nature of the magnetic fields and the nonlinear characteristics of the magnets. A numerical method is described for simulating three-dimensional magnetic fields and used to analyze quadrupole lenses and doublets with permanent magnets. The results, which are confirmed experimentally, indicate that both the quadrupole magnetic gradient and the effective field length are changed in permanent-magnet quadrupole lenses when the pole lengths and the gap between the lenses are varied while the other characteristics of the magnets remain unchanged

  17. Contact lenses fitting after intracorneal ring segments implantation in keratoconus

    Directory of Open Access Journals (Sweden)

    Luciane Bugmann Moreira

    2013-08-01

    Full Text Available PURPOSE: Evaluate contact lenses fitting after intracorneal ring implantation for keratoconus, its visual acuity and comfort. METHODS: Retrospective study of patients undergoing contact lenses fitting, after intracorneal ring for keratoconus. The criterion for contact lens fitting was unsatisfactory visual acuity with spectacle correction as referred by the patients. All patients were intolerants to contact lenses prior to intracorneal implantation. Visual acuity analysis was done by conversion of Snellen to logMAR scales. The comfort was evaluated according subjective questioning of good, medium or poor comfort. RESULTS: Nineteen patients were included in the study. Two patients (10.5% did not achieved good comfort with contact lenses and underwent penetrating keratoplasties. All the others 17 patients showed good or medium comfort. Four rigid gas-permeable contact lenses were fitted, one piggyback approach, 3 toric soft contact lenses, 2 soft lenses specially design for keratoconus and 7 disposable soft lenses. The average visual acuity improved from 0.77 ± 0.37 to 0.19 ± 0.13 logMAR units after contact lenses fitting. CONCLUSION: Contact lens fitting after intracorneal ring is possible, provides good comfort, improves visual acuity, and therefore, may postpone the need for penetrating keratoplasty.

  18. Bacterial adhesion to unworn and worn silicone hydrogel lenses.

    Science.gov (United States)

    Vijay, Ajay Kumar; Zhu, Hua; Ozkan, Jerome; Wu, Duojia; Masoudi, Simin; Bandara, Rani; Borazjani, Roya N; Willcox, Mark D P

    2012-08-01

    The objective of this study was to determine the bacterial adhesion to various silicone hydrogel lens materials and to determine whether lens wear modulated adhesion. Bacterial adhesion (total and viable cells) of Staphylococcus aureus (31, 38, and ATCC 6538) and Pseudomonas aeruginosa (6294, 6206, and GSU-3) to 10 commercially available different unworn and worn silicone hydrogel lenses was measured. Results of adhesion were correlated to polymer and surface properties of contact lenses. S. aureus adhesion to unworn lenses ranged from 2.8 × 10 to 4.4 × 10 colony forming units per lens. The highest adhesion was to lotrafilcon A lenses, and the lowest adhesion was to asmofilcon A lenses. P. aeruginosa adhesion to unworn lenses ranged from 8.9 × 10 to 3.2 × 10 colony forming units per lens. The highest adhesion was to comfilcon A lenses, and the lowest adhesion was to asmofilcon A and balafilcon A lenses. Lens wear altered bacterial adhesion, but the effect was specific to lens and strain type. Adhesion of bacteria, regardless of genera/species or lens wear, was generally correlated with the hydrophobicity of the lens; the less hydrophobic the lens surface, the greater the adhesion. P. aeruginosa adhered in higher numbers to lenses in comparison with S. aureus strains, regardless of the lens type or lens wear. The effect of lens wear was specific to strain and lens. Hydrophobicity of the silicone hydrogel lens surface influenced the adhesion of bacterial cells.

  19. Resonance-enhanced two-photon ionization of ions by Lyman alpha radiation in gaseous nebulae.

    Science.gov (United States)

    Johansson, S; Letokhov, V

    2001-01-26

    One of the mysteries of nebulae in the vicinity of bright stars is the appearance of bright emission spectral lines of ions, which imply fairly high excitation temperatures. We suggest that an ion formation mechanism, based on resonance-enhanced two-photon ionization (RETPI) by intense H Lyman alpha radiation (wavelength of 1215 angstroms) trapped inside optically thick nebulae, can produce these spectral lines. The rate of such an ionization process is high enough for rarefied gaseous media where the recombination rate of the ions formed can be 10(-6) to 10(-8) per second for an electron density of 10(3) to 10(5) per cubic centimeter in the nebula. Under such conditions, the photo-ions formed may subsequently undergo further RETPI, catalyzed by intense He i and He ii radiation, which also gets enhanced in optically thick nebulae that contain enough helium.

  20. Pollen Dispersal by Catapult: Experiments of Lyman J. Briggs on the Flower of Mountain Laurel

    Science.gov (United States)

    Nimmo, John R.; Hermann, Paula M.; Kirkham, M. B.; Landa, Edward R.

    2014-09-01

    The flower of Kalmia latifolia L. employs a catapult mechanism that flings its pollen to considerable distances. Physicist Lyman J. Briggs investigated this phenomenon in the 1950s after retiring as longtime director of the National Bureau of Standards, attempting to explain how hydromechanical effects inside the flower's stamen could make it possible. Briggs's unfinished manuscript implies that liquid under negative pressure generates stress, which, superimposed on the stress generated from the flower's growth habit, results in force adequate to propel the pollen as observed. With new data and biophysical understanding to supplement Briggs's experimental results and research notes, we show that his postulated negative-pressure mechanism did not play the exclusive and crucial role that he credited to it, though his revisited investigation sheds light on various related processes. Important issues concerning the development and reproductive function of Kalmia flowers remain unresolved, highlighting the need for further biophysical advances.

  1. Diagnostics of MCF plasmas using Lyman-α fluorescence excited by one or two photons

    International Nuclear Information System (INIS)

    Voslamber, D.

    1998-11-01

    Laser-induced Lyman-α fluorescence of the hydrogen isotopes is investigated with regard to diagnostic applications in magnetically confined fusion plasmas. A formal analysis is presented for two excitation schemes: one-photon and Doppler-free two-photon excitation. The analysis includes estimates of the expected experimental errors arising from the photon noise and from the sensitivity of the observed fluorescence signals to variations of the plasma and laser parameters. Both excitation schemes are suitable primarily for application in the plasma edge, but even in the plasma bulk of large machines they can still be applied in combination with a diagnostic neutral beam. The two-photon excitation scheme is particularly attractive because it involves absorption spectra that are resolved within the Doppler width. This implies a large diagnostic potential and in particular offers a way to measure the deuterium-tritium fuel mix in fusion reactors. (author)

  2. The effect of asymmetric solar wind on the Lyman α sky background

    International Nuclear Information System (INIS)

    Joselyn, J.A.; Holzer, T.E.

    1975-01-01

    The Lyman α (Ly α) sky background arises from the scattering of solar Ly α from a spatial distribution of neutral hydrogen in interplanetary space. This distribution is partially determined by the solar wind proton flux, which provides the principal mechanism of loss by charge exchange of the neutral hydrogen. By generating isophotal maps of scattered Ly α for several choices of interstellar wind direction and solar wind proton flux distributions, the results show that latitudinal variations of the solar wind proton flux can have a significant effect on the observed location and shape of the Ly α intensity maximum. This fact should aid in the interpretation of Ly α maps and also indicates a possible method for inferring values for the average solar wind proton flux out of the ecliptic plane

  3. A Lyman Break Galaxy in the Epoch of Reionization from Hubble Space Telescope (HST) Grism Spectroscopy

    Science.gov (United States)

    Rhoads, James E.; Malhotra, Sangeeta; Stern, Daniel K.; Gardner, Jonathan P.; Dickinson, Mark; Pirzkal, Norbert; Spinrad, Hyron; Reddy, Naveen; Dey, Arjun; Hathi, Nimish; hide

    2013-01-01

    Slitless grism spectroscopy from space offers dramatic advantages for studying high redshift galaxies: high spatial resolution to match the compact sizes of the targets, a dark and uniform sky background, and simultaneous observation over fields ranging from five square arcminutes (HST) to over 1000 square arcminutes (Euclid). Here we present observations of a galaxy at z = 6.57 the end of the reioinization epoch identified using slitless HST grism spectra from the PEARS survey (Probing Evolution And Reionization Spectroscopically) and reconfirmed with Keck + DEIMOS. This high redshift identification is enabled by the depth of the PEARS survey. Substantially higher redshifts are precluded for PEARS data by the declining sensitivity of the ACS grism at greater than lambda 0.95 micrometers. Spectra of Lyman breaks at yet higher redshifts will be possible using comparably deep observations with IR-sensitive grisms.

  4. Lyman Break Galaxies in the Hubble Ultra Deep Field through Deep U-Band Imaging

    Science.gov (United States)

    Rafelski, Marc; Wolfe, A. M.; Cooke, J.; Chen, H. W.; Armandroff, T. E.; Wirth, G. D.

    2009-12-01

    We introduce an extremely deep U-band image taken of the Hubble Ultra Deep Field (HUDF), with a one sigma depth of 30.7 mag arcsec-2 and a detection limiting magnitude of 28 mag arcsec-2. The observations were carried out on the Keck I telescope using the LRIS-B detector. The U-band image substantially improves the accuracy of photometric redshift measurements of faint galaxies in the HUDF at z=[2.5,3.5]. The U-band for these galaxies is attenuated by lyman limit absorption, allowing for more reliable selections of candidate Lyman Break Galaxies (LBGs) than from photometric redshifts without U-band. We present a reliable sample of 300 LBGs at z=[2.5,3.5] in the HUDF. Accurate redshifts of faint galaxies at z=[2.5,3.5] are needed to obtain empirical constraints on the star formation efficiency of neutral gas at high redshift. Wolfe & Chen (2006) showed that the star formation rate (SFR) density in damped Ly-alpha absorption systems (DLAs) at z=[2.5,3.5] is significantly lower than predicted by the Kennicutt-Schmidt law for nearby galaxies. One caveat to this result that we wish to test is whether LBGs are embedded in DLAs. If in-situ star formation is occurring in DLAs, we would see it as extended low surface brightness emission around LBGs. We shall use the more accurate photometric redshifts to create a sample of LBGs around which we will look for extended emission in the more sensitive and higher resolution HUDF images. The absence of extended emission would put limits on the SFR density of DLAs associated with LBGs at high redshift. On the other hand, detection of faint emission on scales large compared to the bright LBG cores would indicate the presence of in situ star formation in those DLAs. Such gas would presumably fuel the higher star formation rates present in the LBG cores.

  5. Study of interplanetary hydrogen from Lyman alpha emission and absorption determination

    International Nuclear Information System (INIS)

    Cazes, Serge.

    1979-09-01

    The purpose of the work submitted in this paper is to contribute to the study of interplanetary hydrogen from Lyman alpha emission and absorption measurements, carried out on board the D2A, OSO-8 and Copernicus satellites. This study, which was undertaken from the D2A satellite, moved us to study the interplanetary environment as from observations made from the following experiments placed on board the OSO-8 and Copernicus satellites. The experiment set up on board the OSO-8 satellite made it possible to obtain the profile of the solar alpha Lyman emission. An absorption profile was observed for the first time on these profiles and this made it possible to attribute them to interplanetary hydrogen and enabled us to make a direct and local determination of the solar ionization rate. - The spectrometer set up on board Copernicus made it possible to obtain the emission spectrum of the interplanetary environment at the same time as the geocorona. The overall velocity of the interplanetary environment was deduced from the Doppler shift between the two spectra. In the first part, the principle of the REA and POLAR experiments is recalled but only the REA experiment is described in detail, particularly the problems arising from the construction and calibration of the cell. In the second part, a study of the interplanetary environment made from the D2A determinations is presented in synthesized form. On the other hand, the study to which theses initial results led us is presented in detail. Finally, in the third part, the results obtained by means of the OSO-8 and Copernicus satellites are given [fr

  6. Incorporating Single-nucleotide Polymorphisms Into the Lyman Model to Improve Prediction of Radiation Pneumonitis

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, Susan L., E-mail: sltucker@mdanderson.org [Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Li Minghuan [Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, Shandong (China); Xu Ting; Gomez, Daniel [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Yuan Xianglin [Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Yu Jinming [Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, Shandong (China); Liu Zhensheng; Yin Ming; Guan Xiaoxiang; Wang Lie; Wei Qingyi [Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mohan, Radhe [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Vinogradskiy, Yevgeniy [University of Colorado School of Medicine, Aurora, Colorado (United States); Martel, Mary [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liao Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2013-01-01

    Purpose: To determine whether single-nucleotide polymorphisms (SNPs) in genes associated with DNA repair, cell cycle, transforming growth factor-{beta}, tumor necrosis factor and receptor, folic acid metabolism, and angiogenesis can significantly improve the fit of the Lyman-Kutcher-Burman (LKB) normal-tissue complication probability (NTCP) model of radiation pneumonitis (RP) risk among patients with non-small cell lung cancer (NSCLC). Methods and Materials: Sixteen SNPs from 10 different genes (XRCC1, XRCC3, APEX1, MDM2, TGF{beta}, TNF{alpha}, TNFR, MTHFR, MTRR, and VEGF) were genotyped in 141 NSCLC patients treated with definitive radiation therapy, with or without chemotherapy. The LKB model was used to estimate the risk of severe (grade {>=}3) RP as a function of mean lung dose (MLD), with SNPs and patient smoking status incorporated into the model as dose-modifying factors. Multivariate analyses were performed by adding significant factors to the MLD model in a forward stepwise procedure, with significance assessed using the likelihood-ratio test. Bootstrap analyses were used to assess the reproducibility of results under variations in the data. Results: Five SNPs were selected for inclusion in the multivariate NTCP model based on MLD alone. SNPs associated with an increased risk of severe RP were in genes for TGF{beta}, VEGF, TNF{alpha}, XRCC1 and APEX1. With smoking status included in the multivariate model, the SNPs significantly associated with increased risk of RP were in genes for TGF{beta}, VEGF, and XRCC3. Bootstrap analyses selected a median of 4 SNPs per model fit, with the 6 genes listed above selected most often. Conclusions: This study provides evidence that SNPs can significantly improve the predictive ability of the Lyman MLD model. With a small number of SNPs, it was possible to distinguish cohorts with >50% risk vs <10% risk of RP when they were exposed to high MLDs.

  7. CLASH: COMPLETE LENSING ANALYSIS OF THE LARGEST COSMIC LENS MACS J0717.5+3745 AND SURROUNDING STRUCTURES

    International Nuclear Information System (INIS)

    Medezinski, Elinor; Lemze, Doron; Ford, Holland; Umetsu, Keiichi; Nonino, Mario; Merten, Julian; Mroczkowski, Tony; Zitrin, Adi; Broadhurst, Tom; Donahue, Megan; Sayers, Jack; Czakon, Nicole; Waizmann, Jean-Claude; Meneghetti, Massimo; Koekemoer, Anton; Coe, Dan; Postman, Marc; Molino, Alberto; Melchior, Peter; Grillo, Claudio

    2013-01-01

    The galaxy cluster MACS J0717.5+3745 (z = 0.55) is the largest known cosmic lens, with complex internal structures seen in deep X-ray, Sunyaev-Zel'dovich effect, and dynamical observations. We perform a combined weak- and strong-lensing analysis with wide-field BVR c i'z' Subaru/Suprime-Cam observations and 16-band Hubble Space Telescope observations taken as part of the Cluster Lensing And Supernova survey with Hubble. We find consistent weak distortion and magnification measurements of background galaxies and combine these signals to construct an optimally estimated radial mass profile of the cluster and its surrounding large-scale structure out to 5 Mpc h –1 . We find consistency between strong-lensing and weak-lensing in the region where these independent data overlap, –1 . The two-dimensional weak-lensing map reveals a clear filamentary structure traced by distinct mass halos. We model the lensing shear field with nine halos, including the main cluster, corresponding to mass peaks detected above 2.5σ κ . The total mass of the cluster as determined by the different methods is M vir ≈ (2.8 ± 0.4) × 10 15 M ☉ . Although this is the most massive cluster known at z > 0.5, in terms of extreme value statistics, we conclude that the mass of MACS J0717.5+3745 by itself is not in serious tension with ΛCDM, representing only a ∼2σ departure above the maximum simulated halo mass at this redshift

  8. CLASH: COMPLETE LENSING ANALYSIS OF THE LARGEST COSMIC LENS MACS J0717.5+3745 AND SURROUNDING STRUCTURES

    Energy Technology Data Exchange (ETDEWEB)

    Medezinski, Elinor; Lemze, Doron; Ford, Holland [Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Umetsu, Keiichi [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Nonino, Mario [INAF/Osservatorio Astronomico di Trieste, via G.B. Tiepolo 11, I-34143 Trieste (Italy); Merten, Julian; Mroczkowski, Tony [Jet Propulsion Laboratory, California Institute of Technology, MS 169-327, Pasadena, CA 91109 (United States); Zitrin, Adi [Institut für Theoretische Astrophysik, Universität Heidelberg, Zentrum für Astronomie, Philosophenweg 12, D-69120 Heidelberg (Germany); Broadhurst, Tom [Department of Theoretical Physics and History of Science, University of the Basque Country UPV/EHU, P.O. Box 644, E-48080 Bilbao (Spain); Donahue, Megan [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Sayers, Jack; Czakon, Nicole [Division of Physics, Math, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Waizmann, Jean-Claude; Meneghetti, Massimo [Dipartimento di Astronomia, Universit' a di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Koekemoer, Anton; Coe, Dan; Postman, Marc [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21208 (United States); Molino, Alberto [Instituto de Astrofísica de Andalucía (CSIC), E-18080 Granada (Spain); Melchior, Peter [Center for Cosmology and Astro-Particle Physics and Department of Physics, The Ohio State University, Columbus, OH 43210 (United States); Grillo, Claudio, E-mail: elinor@pha.jhu.edu [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Mariesvej 30, DK-2100 Copenhagen (Denmark); and others

    2013-11-01

    The galaxy cluster MACS J0717.5+3745 (z = 0.55) is the largest known cosmic lens, with complex internal structures seen in deep X-ray, Sunyaev-Zel'dovich effect, and dynamical observations. We perform a combined weak- and strong-lensing analysis with wide-field BVR{sub c} i'z' Subaru/Suprime-Cam observations and 16-band Hubble Space Telescope observations taken as part of the Cluster Lensing And Supernova survey with Hubble. We find consistent weak distortion and magnification measurements of background galaxies and combine these signals to construct an optimally estimated radial mass profile of the cluster and its surrounding large-scale structure out to 5 Mpc h {sup –1}. We find consistency between strong-lensing and weak-lensing in the region where these independent data overlap, <500 kpc h {sup –1}. The two-dimensional weak-lensing map reveals a clear filamentary structure traced by distinct mass halos. We model the lensing shear field with nine halos, including the main cluster, corresponding to mass peaks detected above 2.5σ{sub κ}. The total mass of the cluster as determined by the different methods is M{sub vir} ≈ (2.8 ± 0.4) × 10{sup 15} M{sub ☉}. Although this is the most massive cluster known at z > 0.5, in terms of extreme value statistics, we conclude that the mass of MACS J0717.5+3745 by itself is not in serious tension with ΛCDM, representing only a ∼2σ departure above the maximum simulated halo mass at this redshift.

  9. Spurious Shear in Weak Lensing with LSST

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.; Kahn, S.M.; Jernigan, J.G.; Peterson, J.R.; AlSayyad, Y.; Ahmad, Z.; Bankert, J.; Bard, D.; Connolly, A.; Gibson, R.R.; Gilmore, K.; Grace, E.; Hannel, M.; Hodge, M.A.; Jee, M.J.; Jones, L.; Krughoff, S.; Lorenz, S.; Marshall, P.J.; Marshall, S.; Meert, A.

    2012-09-19

    The complete 10-year survey from the Large Synoptic Survey Telescope (LSST) will image {approx} 20,000 square degrees of sky in six filter bands every few nights, bringing the final survey depth to r {approx} 27.5, with over 4 billion well measured galaxies. To take full advantage of this unprecedented statistical power, the systematic errors associated with weak lensing measurements need to be controlled to a level similar to the statistical errors. This work is the first attempt to quantitatively estimate the absolute level and statistical properties of the systematic errors on weak lensing shear measurements due to the most important physical effects in the LSST system via high fidelity ray-tracing simulations. We identify and isolate the different sources of algorithm-independent, additive systematic errors on shear measurements for LSST and predict their impact on the final cosmic shear measurements using conventional weak lensing analysis techniques. We find that the main source of the errors comes from an inability to adequately characterise the atmospheric point spread function (PSF) due to its high frequency spatial variation on angular scales smaller than {approx} 10{prime} in the single short exposures, which propagates into a spurious shear correlation function at the 10{sup -4}-10{sup -3} level on these scales. With the large multi-epoch dataset that will be acquired by LSST, the stochastic errors average out, bringing the final spurious shear correlation function to a level very close to the statistical errors. Our results imply that the cosmological constraints from LSST will not be severely limited by these algorithm-independent, additive systematic effects.

  10. Effect of cholesterol deposition on bacterial adhesion to contact lenses.

    Science.gov (United States)

    Babaei Omali, Negar; Zhu, Hua; Zhao, Zhenjun; Ozkan, Jerome; Xu, Banglao; Borazjani, Roya; Willcox, Mark D P

    2011-08-01

    To examine the effect of cholesterol on the adhesion of bacteria to silicone hydrogel contact lenses. Contact lenses, collected from subjects wearing Acuvue Oasys or PureVision lenses, were extracted in chloroform:methanol (1:1, v/v) and amount of cholesterol was estimated by thin-layer chromatography. Unworn lenses were soaked in cholesterol, and the numbers of Pseudomonas aeruginosa strains or Staphylococcus aureus strains that adhered to the lenses were measured. Cholesterol was tested for effects on bacterial growth by incubating bacteria in medium containing cholesterol. From ex vivo PureVision lenses, 3.4 ± 0.3 μg/lens cholesterol was recovered, and from Acuvue Oasys lenses, 2.4 ± 0.2 to 1.0 ± 0.1 μg/lens cholesterol was extracted. Cholesterol did not alter the total or viable adhesion of any strain of P. aeruginosa or S. aureus (p > 0.05). However, worn PureVision lenses reduced the numbers of viable cells of P. aeruginosa (5.8 ± 0.4 log units) compared with unworn lenses (6.4 ± 0.2 log units, p = 0.001). Similarly, there were fewer numbers of S. aureus 031 adherent to worn PureVision (3.05 ± 0.8 log units) compared with unworn PureVision (4.6 ± 0.3 log units, p = 0.0001). Worn Acuvue Oasys lenses did not affect bacterial adhesion. Cholesterol showed no effect on the growth of any test strain. Although cholesterol has been shown to adsorb to contact lenses during wear, this lipid does not appear to modulate bacterial adhesion to a lens surface.

  11. The lensing properties of the Einasto profile

    OpenAIRE

    Retana-Montenegro, E.; Frutos-Alfaro, F.

    2011-01-01

    In recent high resolution N-body CDM simulations, it has been had found that nonsingular three-parameter models, e.g. the Einasto profile has a better performance better than the singular two-parameter models, e.g. the Navarro, Frenk and White in the fitting of a wide range of dark matter halos. A problem with this profile is that the surface mass density is non-analytical for general values of the Einasto index. Therefore, its other lensing properties have the same problem. We obtain an exac...

  12. Optimizing outcomes with multifocal intraocular lenses

    Directory of Open Access Journals (Sweden)

    Gitansha Shreyas Sachdev

    2017-01-01

    Full Text Available Modern day cataract surgery is evolving from a visual restorative to a refractive procedure. The advent of multifocal intraocular lenses (MFIOLs allows greater spectacle independence and increased quality of life postoperatively. Since the inception in 1980s, MFIOLs have undergone various technical advancements including trifocal and extended depth of vision implants more recently. A thorough preoperative workup including the patients' visual needs and inherent ocular anatomy allows us to achieve superior outcomes. This review offers a comprehensive overview of the various types of MFIOLs and principles of optimizing outcomes through a comprehensive preoperative screening and management of postoperative complications.

  13. Electron Beam Generation in Tevatron Electron Lenses

    International Nuclear Information System (INIS)

    Kamerdzhiev, V.; Kuznetsov, G.; Shiltsev, V.; Solyak, N.; Tiunov, M.

    2006-01-01

    New type of high perveance electron guns with convex cathode has been developed. Three guns described in this article are built to provide transverse electron current density distributions needed for Electron Lenses for beam-beam compensation in the Tevatron collider. The current distribution can be controlled either by the gun geometry or by voltage on a special control electrode located near cathode. We present the designs of the guns and report results of beam measurements on the test bench. Because of their high current density and low transverse temperature of electrons, electron guns of this type can be used in electron cooling and beam-beam compensation devices

  14. Electron beam generation in Tevatron electron lenses

    International Nuclear Information System (INIS)

    Kamerdzhiev, V.; Kuznetsov, G.; Shiltsev, V.; Solyak, N.; Tiunov, M.

    2006-01-01

    New type of high perveance electron guns with convex cathode has been developed. Three guns described in this article are built to provide transverse electron current density distributions needed for Electron Lenses for beam-beam compensation in the Tevatron collider. The current distribution can be controlled either by the gun geometry or by voltage on a special control electrode located near cathode. We present the designs of the guns and report results of beam measurements on the test bench. Because of their high current density and low transverse temperature of electrons, electron guns of this type can be used in electron cooling and beam-beam compensation devices

  15. Characterisation of adaptive fluidic silicone membrane lenses

    CSIR Research Space (South Africa)

    Schneider, F

    2009-09-01

    Full Text Available membrane shapes for a lens volume of 1 µl at divorce homogeneous membrane thicknesses. The measurement of the system behaviour is realized by the laser-profilometer in the dynamic mode. For the lens with a homogeneous membrane the membrane surface..., inhomogeneous membranes is application specific. On the one hand, systems with planar mem- branes are reasonable for a large focal length range, a constant optical lens quality and a short response time. On the other hand, the application of lenses...

  16. The large-scale cross-correlation of Damped Lyman alpha systems with the Lyman alpha forest: first measurements from BOSS

    Energy Technology Data Exchange (ETDEWEB)

    Font-Ribera, Andreu [Institute of Theoretical Physics, University of Zurich, 8057 Zurich (Switzerland); Miralda-Escudé, Jordi [Institució Catalana de Recerca i Estudis Avançats, Barcelona, Catalonia (Spain); Arnau, Eduard [Institut de Ciències del Cosmos (IEEC/UB), Barcelona, Catalonia (Spain); Carithers, Bill; Ross, Nicholas P.; White, Martin [Lawrence Berkeley National Laboratory, University of California Berkeley, Berkeley, California 94720 (United States); Lee, Khee-Gan [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany); Noterdaeme, Pasquier; Pâris, Isabelle; Petitjean, Patrick; Rollinde, Emmanuel [Institut d' Astrophysique de Paris, Université Paris 6 et CNRS, 98bis blvd. Arago, 75014 Paris (France); Rich, James [CEA, Centre de Saclay, IRFU, 91191 Gif-sur-Yvette (France); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); York, Donald G., E-mail: font@physik.uzh.ch, E-mail: miralda@icc.ub.edu [Department of Astronomy and Astrophysics and The Fermi Institute, Chicago University, 5640 So. Ellis Ave., Chicago, IL 60637 (United States)

    2012-11-01

    We present the first measurement of the large-scale cross-correlation of Lyα forest absorption and Damped Lyman α systems (DLA), using the 9th Data Release of the Baryon Oscillation Spectroscopic Survey (BOSS). The cross-correlation is clearly detected on scales up to 40h{sup −1}Mpc and is well fitted by the linear theory prediction of the standard Cold Dark Matter model of structure formation with the expected redshift distortions, confirming its origin in the gravitational evolution of structure. The amplitude of the DLA-Lyα cross-correlation depends on only one free parameter, the bias factor of the DLA systems, once the Lyα forest bias factors are known from independent Lyα forest correlation measurements. We measure the DLA bias factor to be b{sub D} = (2.17±0.20)β{sub F}{sup 0.22}, where the Lyα forest redshift distortion parameter β{sub F} is expected to be above unity. This bias factor implies a typical host halo mass for DLAs that is much larger than expected in present DLA models, and is reproduced if the DLA cross section scales with halo mass as M{sub h}{sup α}, with α = 1.1±0.1 for β{sub F} = 1. Matching the observed DLA bias factor and rate of incidence requires that atomic gas remains extended in massive halos over larger areas than predicted in present simulations of galaxy formation, with typical DLA proper sizes larger than 20 kpc in host halos of masses ∼ 10{sup 12}M{sub ☉}. We infer that typical galaxies at z ≅ 2 to 3 are surrounded by systems of atomic clouds that are much more extended than the luminous parts of galaxies and contain ∼ 10% of the baryons in the host halo.

  17. Constraints on early-type galaxy structure from spectroscopically selected gravitational lenses

    Science.gov (United States)

    Bolton, Adam Stallard

    2005-11-01

    This thesis describes all aspects of a unique spectroscopic survey for strong galaxy-galaxy gravitational lenses: motivation, candidate selection, ground- based spectroscopic follow-up, Hubble Space Telescope imaging, data analysis, and results on the radial density profile of the lens galaxies. The lens candidates are selected from within the spectroscopic database of the Sloan Digital Sky Survey (SDSS) based on the appearance of two significantly different redshifts along the same line of sight, and lenses are confirmed within the candidate sample by follow-up imaging and spectroscopy. The sample of [approximate]20 early-type lenses presented in this thesis represents the largest single strong-lens galaxy sample discovered and published to date. These lenses probe the mass of the lens galaxies on scales roughly equal to one-half effective radius. We find a dynamical normalization between isothermal lens-model velocity dispersions and aperture-corrected SDSS stellar velocity dispersions of f = s lens /s stars = 0.95 +/- 0.03. By combining lens-model Einstein radii and de Vaucouleurs effective radii with stellar velocity dispersions through the Jeans equation, we find that the logarithmic slope [Special characters omitted.] of the density profile in our lens galaxies (r 0 ( [Special characters omitted.] ) is on average slightly steeper than isothermal ([Special characters omitted.] = 2) with a modest intrinsic scatter. Parameterizing the intrinsic distribution in [Special characters omitted.] as Gaussian, we find a maximum-likelihood mean of [Special characters omitted. ] and standard deviation of s[Special characters omitted.] = [Special characters omitted.] (68% confidence, for isotropic velocity-dispersion models). Our results rule out a single universal logarithmic density slope at >99.995% confidence. The success of this spectroscopic lens survey suggests that similar projects should be considered as an explicit science goal of future redshift surveys. (Copies

  18. Gauge-invariant formalism of cosmological weak lensing

    Science.gov (United States)

    Yoo, Jaiyul; Grimm, Nastassia; Mitsou, Ermis; Amara, Adam; Refregier, Alexandre

    2018-04-01

    We present the gauge-invariant formalism of cosmological weak lensing, accounting for all the relativistic effects due to the scalar, vector, and tensor perturbations at the linear order. While the light propagation is fully described by the geodesic equation, the relation of the photon wavevector to the physical quantities requires the specification of the frames, where they are defined. By constructing the local tetrad bases at the observer and the source positions, we clarify the relation of the weak lensing observables such as the convergence, the shear, and the rotation to the physical size and shape defined in the source rest-frame and the observed angle and redshift measured in the observer rest-frame. Compared to the standard lensing formalism, additional relativistic effects contribute to all the lensing observables. We explicitly verify the gauge-invariance of the lensing observables and compare our results to previous work. In particular, we demonstrate that even in the presence of the vector and tensor perturbations, the physical rotation of the lensing observables vanishes at the linear order, while the tetrad basis rotates along the light propagation compared to a FRW coordinate. Though the latter is often used as a probe of primordial gravitational waves, the rotation of the tetrad basis is indeed not a physical observable. We further clarify its relation to the E-B decomposition in weak lensing. Our formalism provides a transparent and comprehensive perspective of cosmological weak lensing.

  19. 30 CFR 18.66 - Tests of windows and lenses.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tests of windows and lenses. 18.66 Section 18... Tests § 18.66 Tests of windows and lenses. (a) Impact tests. A 4-pound cylindrical weight with a 1-inch-diameter hemispherical striking surface shall be dropped (free fall) to strike the window or lens in its...

  20. Dimensional stability of lathe cut C.A.B. lenses.

    Science.gov (United States)

    Pearson, R M

    1978-08-01

    Measurements of the back central optical radius in the course of 336 hours of hydration of lathe cut corneal lenses disclosed changes in curvature which were more rapid and of greater magnitude than those previously reported for poly (methyl methacrylate) lenses.

  1. Influence of protein deposition on bacterial adhesion to contact lenses.

    Science.gov (United States)

    Subbaraman, Lakshman N; Borazjani, Roya; Zhu, Hua; Zhao, Zhenjun; Jones, Lyndon; Willcox, Mark D P

    2011-08-01

    The aim of the study is to determine the adhesion of Gram positive and Gram negative bacteria onto conventional hydrogel (CH) and silicone hydrogel (SH) contact lens materials with and without lysozyme, lactoferrin, and albumin coating. Four lens types (three SH-balafilcon A, lotrafilcon B, and senofilcon A; one CH-etafilcon A) were coated with lysozyme, lactoferrin, or albumin (uncoated lenses acted as controls) and then incubated in Staphylococcus aureus (Saur 31) or either of two strains of Pseudomonas aeruginosa (Paer 6294 and 6206) for 24 h at 37 °C. The total counts of the adhered bacteria were determined using the H-thymidine method and viable counts by counting the number of colony-forming units on agar media. All three strains adhered significantly lower to uncoated etafilcon A lenses compared with uncoated SH lenses (p 0.05). Lactoferrin coating on lenses increased binding (total and viable counts) of Saur 31 (p lenses showed significantly higher total counts (p lenses. Albumin coating of lenses increased binding (total and viable counts) of all three strains (p lenses does not possess antibacterial activity against certain bacterial strains, whereas lactoferrin possess an antibacterial effect against strains of P. aeruginosa.

  2. Biochemical analyses of lipids deposited on silicone hydrogel lenses

    Directory of Open Access Journals (Sweden)

    Shin Hatou

    2010-07-01

    Conclusions: The quantity of total lipid and cholesterol deposited on the 3 silicone hydrogel lenses tested did not differ. However, there were significant differences in the amounts of phospholipid deposited among the 3 silicone hydrogel lenses, of which clinical significance should be explored in the future study.

  3. Shallow rainwater lenses in deltaic areas with saline seepage

    NARCIS (Netherlands)

    Louw, de P.G.B.; Eeman, S.; Siemon, B.; `Voortman, B.R.; Gunnink, J.; Baaren, E.S.; Oude Essink, G.H.P.

    2011-01-01

    In deltaic areas with saline seepage, freshwater availability is often limited to shallow rainwater lenses lying on top of saline groundwater. Here we describe the characteristics and spatial variability of such lenses in areas with saline seepage and the mechanisms that control their occurrence and

  4. Shallow rainwater lenses in deltaic areas with saline seepage

    NARCIS (Netherlands)

    De Louw, Perry G.B.; Eeman, Sara; Siemon, Bernhard; Voortman, Bernard R.; Gunnink, Jan; Van Baaren, Esther S.; Oude Essink, Gualbert

    2011-01-01

    In deltaic areas with saline seepage, fresh water availability is often limited to shallow rainwater lenses lying on top of saline groundwater. Here we describe the characteristics and spatial variability of such lenses in areas with saline seepage and the mechanisms that control their occurrence

  5. From Spheric to Aspheric Solid Polymer Lenses: A Review

    Directory of Open Access Journals (Sweden)

    Kuo-Yung Hung

    2011-01-01

    Full Text Available This paper presents a new approach in the use of MEMS technology to fabricate micro-optofluidic polymer solid lenses in order to achieve the desired profile, focal length, numerical aperture, and spot size. The resulting polymer solid lenses can be applied in optical data storage systems, imaging systems, and automated optical inspection systems. In order to meet the various needs of different applications, polymer solid lenses may have a spherical or aspherical shape. The method of fabricating polymer solid lenses is different from methods used to fabricate tunable lenses with variable focal length or needing an external control system to change the lens geometry. The current trend in polymer solid lenses is toward the fabrication of microlenses with a high numerical aperture, small clear aperture (<2 mm, and high transmittance. In this paper we focus on the use of thermal energy and electrostatic force in shaping the lens profile, including both spherical and aspherical lenses. In addition, the paper discusses how to fabricate a lens with a high numerical aperture of 0.6 using MEMS and also compares the optical characteristics of polymer lens materials, including SU-8, Norland Optical Adhesive (NOA, and cyclic olefin copolymer (COC. Finally, new concepts and applications related to micro-optofluidic lenses and polymer materials are also discussed.

  6. Fermat potentials for nonperturbative gravitational lensing

    International Nuclear Information System (INIS)

    Frittelli, Simonetta; Kling, Thomas P.; Newman, Ezra T.

    2002-01-01

    The images of many distant galaxies are displaced, distorted and often multiplied by the presence of foreground massive galaxies near the line of sight; the foreground galaxies act as gravitational lenses. Commonly, the lens equation, which relates the placement and distortion of the images to the real source position in the thin-lens scenario, is obtained by extremizing the time of arrival among all the null paths from the source to the observer (Fermat's principle). We show that the construction of envelopes of certain families of null surfaces constitutes an alternative variational principle or version of Fermat's principle that leads naturally to a lens equation in a generic spacetime with any given metric. We illustrate the construction by deriving the lens equation for static asymptotically flat thin lens spacetimes. As an application of the approach, we find the bending angle for moving thin lenses in terms of the bending angle for the same deflector at rest. Finally we apply this construction to cosmological spacetimes (FRW) by using the fact they are all conformally related to Minkowski space

  7. Tackling The Dragon: Investigating Lensed Galaxy Structure

    Science.gov (United States)

    Fortenberry, Alexander; Livermore, Rachael

    2018-01-01

    Galaxies have been seen to have a rapid decrease in star formation beginning at a redshift of around 1-2 up to the present day. To understand the processes underpinning this change, we need to observe the inner structure of galaxies and understand where and how the stellar mass builds up. However, at high redshifts our observable resolution is limited, which hinders the accuracy of the data. The lack of resolution at high redshift can be counteracted with the use of gravitational lensing. The magnification provided by the gravitational lens between us and the galaxies in question enables us to see extreme detail within the galaxies. To begin fine-tuning this process, we used Hubble data of Abell 370, a galaxy cluster, which lenses a galaxy know as “The Dragon” at z=0.725. With the increased detail proved by the gravitational lens we provide a detailed analysis of the galaxy’s spatially resolved star formation rate, stellar age, and masses.

  8. The theory of stochastic cosmological lensing

    Energy Technology Data Exchange (ETDEWEB)

    Fleury, Pierre; Uzan, Jean-Philippe [Institut d' Astrophysique de Paris, UMR 7095 du CNRS, 98 bis Bd Arago, 75014 Paris (France); Larena, Julien, E-mail: fleury@iap.fr, E-mail: j.larena@ru.ac.za, E-mail: uzan@iap.fr [Department of Mathematics, Rhodes University, Grahamstown 6140 (South Africa)

    2015-11-01

    On the scale of the light beams subtended by small sources, e.g. supernovae, matter cannot be accurately described as a fluid, which questions the applicability of standard cosmic lensing to those cases. In this article, we propose a new formalism to deal with small-scale lensing as a diffusion process: the Sachs and Jacobi equations governing the propagation of narrow light beams are treated as Langevin equations. We derive the associated Fokker-Planck-Kolmogorov equations, and use them to deduce general analytical results on the mean and dispersion of the angular distance. This formalism is applied to random Einstein-Straus Swiss-cheese models, allowing us to: (1) show an explicit example of the involved calculations; (2) check the validity of the method against both ray-tracing simulations and direct numerical integration of the Langevin equation. As a byproduct, we obtain a post-Kantowski-Dyer-Roeder approximation, accounting for the effect of tidal distortions on the angular distance, in excellent agreement with numerical results. Besides, the dispersion of the angular distance is correctly reproduced in some regimes.

  9. Adaptive lenses using transparent dielectric elastomer actuators

    Science.gov (United States)

    Shian, Samuel; Diebold, Roger; Clarke, David

    2013-03-01

    Variable focal lenses, used in a vast number of applications such as endoscope, digital camera, binoculars, information storage, communication, and machine vision, are traditionally constructed as a lens system consisting of solid lenses and actuating mechanisms. However, such lens system is complex, bulky, inefficient, and costly. Each of these shortcomings can be addressed using an adaptive lens that performs as a lens system. In this presentation, we will show how we push the boundary of adaptive lens technology through the use of a transparent electroactive polymer actuator that is integral to the optics. Detail of our concepts and lens construction will be described as well as electromechanical and optical performances. Preliminary data indicate that our adaptive lens prototype is capable of varying its focus by more than 100%, which is higher than that of human eyes. Furthermore, we will show how our approach can be used to achieve certain controls over the lens characteristics such as adaptive aberration and optical axis, which are difficult or impossible to achieve in other adaptive lens configurations.

  10. Probing neutrino masses with CMB lensing extraction

    International Nuclear Information System (INIS)

    Lesgourgues, Julien; Perotto, Laurence; Pastor, Sergio; Piat, Michel

    2006-01-01

    We evaluate the ability of future cosmic microwave background (CMB) experiments to measure the power spectrum of large scale structure using quadratic estimators of the weak lensing deflection field. We calculate the sensitivity of upcoming CMB experiments such as BICEP, QUaD, BRAIN, ClOVER and Planck to the nonzero total neutrino mass M ν indicated by current neutrino oscillation data. We find that these experiments greatly benefit from lensing extraction techniques, improving their one-sigma sensitivity to M ν by a factor of order four. The combination of data from Planck and the SAMPAN mini-satellite project would lead to σ(M ν )∼0.1 eV, while a value as small as σ(M ν )∼0.035 eV is within the reach of a space mission based on bolometers with a passively cooled 3-4 m aperture telescope, representative of the most ambitious projects currently under investigation. We show that our results are robust not only considering possible difficulties in subtracting astrophysical foregrounds from the primary CMB signal but also when the minimal cosmological model (Λ Mixed Dark Matter) is generalized in order to include a possible scalar tilt running, a constant equation-of-state parameter for the dark energy and/or extra relativistic degrees of freedom

  11. Total molecular gas masses of Planck - Herschel selected strongly lensed hyper luminous infrared galaxies

    Science.gov (United States)

    Harrington, K. C.; Yun, M. S.; Magnelli, B.; Frayer, D. T.; Karim, A.; Weiß, A.; Riechers, D.; Jiménez-Andrade, E. F.; Berman, D.; Lowenthal, J.; Bertoldi, F.

    2018-03-01

    We report the detection of CO(1-0) line emission from seven Planck and Herschel selected hyper luminous ({L_{IR (8-1000{μ m})} > 10^{13} L_{⊙}) infrared galaxies with the Green Bank Telescope (GBT). CO(1-0) measurements are a vital tool to trace the bulk molecular gas mass across all redshifts. Our results place tight constraints on the total gas content of these most apparently luminous high-z star-forming galaxies (apparent IR luminosities of LIR > 1013 - 14 L⊙), while we confirm their predetermined redshifts measured using the Large Millimeter Telescope, LMT (zCO = 1.33-3.26). The CO(1-0) lines show similar profiles as compared to Jup = 2-4 transitions previously observed with the LMT. We report enhanced infrared to CO line luminosity ratios of = 110 ± 22 L_{⊙} (K km s^{-1} pc^{-2})^{-1} compared to normal star-forming galaxies, yet similar to those of well-studied IR-luminous galaxies at high-z. We find average brightness temperature ratios of 〈 r21〉 = 0.93 (2 sources), 〈 r31〉 = 0.34 (5 sources), and 〈 r41〉 = 0.18 (1 source). The r31 and r41 values are roughly half the average values for SMGs. We estimate the total gas mass content as {μ M_{H2} = (0.9-27.2) × 10^{11} (α _CO/0.8) M_{⊙}, where μ is the magnification factor and αCO is the CO line luminosity to molecular hydrogen gas mass conversion factor. The rapid gas depletion times, = 80} Myr, reveal vigorous starburst activity, and contrast the Gyr depletion time-scales observed in local, normal star-forming galaxies.

  12. Probabilistic Cosmological Mass Mapping from Weak Lensing Shear

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M. D.; Dawson, W. A. [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Ng, K. Y. [University of California, Davis, Davis, CA 95616 (United States); Marshall, P. J. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94035 (United States); Meyers, J. E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Bard, D. J., E-mail: schneider42@llnl.gov, E-mail: dstn@cmu.edu, E-mail: boutigny@in2p3.fr, E-mail: djbard@slac.stanford.edu, E-mail: jmeyers314@stanford.edu [National Energy Research Scientific Computing Center, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720-8150 (United States)

    2017-04-10

    We infer gravitational lensing shear and convergence fields from galaxy ellipticity catalogs under a spatial process prior for the lensing potential. We demonstrate the performance of our algorithm with simulated Gaussian-distributed cosmological lensing shear maps and a reconstruction of the mass distribution of the merging galaxy cluster Abell 781 using galaxy ellipticities measured with the Deep Lens Survey. Given interim posterior samples of lensing shear or convergence fields on the sky, we describe an algorithm to infer cosmological parameters via lens field marginalization. In the most general formulation of our algorithm we make no assumptions about weak shear or Gaussian-distributed shape noise or shears. Because we require solutions and matrix determinants of a linear system of dimension that scales with the number of galaxies, we expect our algorithm to require parallel high-performance computing resources for application to ongoing wide field lensing surveys.

  13. CMB lensing constraints on dark energy and modified gravity scenarios

    International Nuclear Information System (INIS)

    Calabrese, Erminia; Cooray, Asantha; Martinelli, Matteo; Melchiorri, Alessandro; Pagano, Luca; Slosar, Anze; Smoot, George F.

    2009-01-01

    Weak gravitational lensing leaves a characteristic imprint on the cosmic microwave background temperature and polarization angular power spectra. Here, we investigate the possible constraints on the integrated lensing potential from future cosmic microwave background angular spectra measurements expected from Planck and EPIC. We find that Planck and EPIC will constrain the amplitude of the integrated projected potential responsible for lensing at 6% and 1% level, respectively, with very little sensitivity to the shape of the lensing potential. We discuss the implications of such a measurement in constraining dark energy and modified gravity scalar-tensor theories. We then discuss the impact of a wrong assumption on the weak lensing potential amplitude on cosmological parameter inference.

  14. Dark energy and curvature from a future baryonic acoustic oscillation survey using the Lyman-α forest

    International Nuclear Information System (INIS)

    McDonald, Patrick; Eisenstein, Daniel J.

    2007-01-01

    We explore the requirements for a Lyman-α forest survey designed to measure the angular diameter distance and Hubble parameter at 2 or approx. 250 spectrograph is sufficient to measure both the radial and transverse oscillation scales to 1.4% from the Lyα forest (or better, if fainter magnitudes and possibly Lyman-break galaxies can be used). At fixed integration time and in the sky-noise-dominated limit, a wider, noisier survey is generally more efficient; the only fundamental upper limit on noise being the need to identify a quasar and find a redshift. Because the Lyα forest is much closer to linear and generally better understood than galaxies, systematic errors are even less likely to be a problem

  15. Corneal erosions, bacterial contamination of contact lenses, and microbial keratitis.

    Science.gov (United States)

    Willcox, Mark D P; Naduvilath, Thomas J; Vaddavalli, Pravin K; Holden, Brien A; Ozkan, Jerome; Zhu, Hua

    2010-11-01

    To estimate the rate of corneal erosion coupled with gram-negative bacterial contamination of contact lenses and compare this with the rate of microbial keratitis (MK) with contact lenses. The rate of corneal erosion and contact lens contamination by gram-negative bacteria were calculated from several prospective trials. These rates were used to calculate the theoretical rate of corneal erosion happening at the same time as wearing a contact lens contaminated with gram-negative bacteria. This theoretical rate was then compared with the rates of MK reported in various epidemiological and clinical trials. Corneal erosions were more frequent during extended wear (0.6-2.6% of visits) compared with daily wear (0.01-0.05% of visits). No corneal erosions were observed for lenses worn on a daily disposable basis. Contamination rates for lenses worn on a daily disposable basis were the lowest (2.4%), whereas they were the highest for low Dk lenses worn on an extended wear basis (7.1%). The estimated rate of corneal erosions occurring at the same time as wearing lenses contaminated with gram-negative bacteria was the lowest during daily wear of low Dk lenses (1.56/10,000 [95% CI: 0.23-10.57]) and the highest during extended wear of high Dk lenses (38.55/10,000 [95% CI: 24.77-60.04]). These rates were similar in magnitude to the rates reported for MK of different hydrogel lenses worn on differing wear schedules. The coincidence of corneal erosions during lens wear with gram-negative bacterial contamination of lenses may account for the relative incidence of MK during lens wear with different lens materials and modes of use.

  16. Lenses matching of compound eye for target positioning

    Science.gov (United States)

    Guo, Fang; Zheng, Yan Pei; Wang, Keyi

    2012-10-01

    Compound eye, as a new imaging method with multi-lens for a large field of view, could complete target positioning and detection fastly, especially at close range. Therefore it could be applicated in the fields of military and medical treatment and aviation with vast market potential and development prospect. Yet the compound eye imaging method designed use three layer construction of multiple lens array arranged in a curved surface and refractive lens and imaging sensor of CMOS. In order to simplify process structure and increase the imaging area of every sub-eye, the imaging area of every eye is coved with the whole CMOS. Therefore, for several imaging point of one target, the corresponding lens of every imaging point is unkonown, and thus to identify. So an algorithm was put forward. Firstly, according to the Regular Geometry relationship of several adjacent lenses, data organization of seven lenses with a main lens was built. Subsequently, by the data organization, when one target was caught by several unknown lenses, we search every combined type of the received lenses. And for every combined type, two lenses were selected to combine and were used to calculate one three-dimensional (3D) coordinate of the target. If the 3D coordinates are same to the some combine type of the lenses numbers, in theory, the lenses and the imaging points are matched. So according to error of the 3D coordinates is calculated by the different seven lenses numbers combines, the unknown lenses could be distinguished. The experimental results show that the presented algorithm is feasible and can complete matching task for imaging points and corresponding lenses.

  17. Performance Characterization of UV Science Cameras Developed for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)

    Science.gov (United States)

    Champey, Patrick; Kobayashi, Ken; Winebarger, Amy; Cirtin, Jonathan; Hyde, David; Robertson, Bryan; Beabout, Brent; Beabout, Dyana; Stewart, Mike

    2014-01-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras will be built and tested for flight with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The goal of the CLASP mission is to observe the scattering polarization in Lyman-alpha and to detect the Hanle effect in the line core. Due to the nature of Lyman-alpha polarization in the chromosphere, strict measurement sensitivity requirements are imposed on the CLASP polarimeter and spectrograph systems; science requirements for polarization measurements of Q/I and U/I are 0.1% in the line core. CLASP is a dual-beam spectro-polarimeter, which uses a continuously rotating waveplate as a polarization modulator, while the waveplate motor driver outputs trigger pulses to synchronize the exposures. The CCDs are operated in frame-transfer mode; the trigger pulse initiates the frame transfer, effectively ending the ongoing exposure and starting the next. The strict requirement of 0.1% polarization accuracy is met by using frame-transfer cameras to maximize the duty cycle in order to minimize photon noise. Coating the e2v CCD57-10 512x512 detectors with Lumogen-E coating allows for a relatively high (30%) quantum efficiency at the Lyman-$\\alpha$ line. The CLASP cameras were designed to operate with =10 e- /pixel/second dark current, = 25 e- read noise, a gain of 2.0 and =0.1% residual non-linearity. We present the results of the performance characterization study performed on the CLASP prototype camera; dark current, read noise, camera gain and residual non-linearity.

  18. Diagnosing the reionization of the universe - The absorption spectrum of the intergalactic medium and Lyman alpha clouds

    Science.gov (United States)

    Giroux, Mark L.; Shapiro, Paul R.

    1991-01-01

    The thermal and ionization evolution of a uniform intergalactic medium composed of H and He and undergoing reionization is studied. The diagnosis of the metagalactic ionizing radiation background at z of about three using metal line ratios for Lyman limit quasar absorption line systems is addressed. The use of the He II Gunn-Peterson effect to diagnose the reionization source and/or nature of the Hy-alpha forest clouds is considered.

  19. Measurement of the Antiprotonic Lyman- and Balmer X-rays of $\\overline{p}H$ and $\\overline{p}D$ Atoms at Very Low Target Pressures

    CERN Multimedia

    2002-01-01

    The aim of this experiment is to measure the energies and intensities of the n @A 1 (Lyman) and n @A 2 (Balmer) tansitions with high accuracy in both @*H and @*D, from which the strong interaction effects of the 1s- and 2p-level can be extracted. These observables may be related to the antiproton-proton and antiproton-neutron scattering length. \\\\ \\\\ Since in these targets collisional Stark effect occurs, we will stop the antiprotons in extreme thin gaseous targets (pressure as low as 10 Torr), where no Stark effect occurs and the 2-1 transition is favoured. In order to use antiprotons with high efficiency despite of the low target density, we will trap antiprotons of a momentum of 100 MeV/c in a magnetic field of cyclotron characteristics. The antiprotons are decelerated by their energy loss in the target gas. The focusing properties of the magnetic field serve to compensate the multiple scattering and we will end up with a concentrated stopping distribution at the centre. Due to the long orbiting time, back...

  20. Detection of 3-Minute Oscillations in Full-Disk Lyman-alpha Emission During A Solar Flare

    Science.gov (United States)

    Milligan, R. O.; Ireland, J.; Fleck, B.; Hudson, H. S.; Fletcher, L.; Dennis, B. R.

    2017-12-01

    We report the detection of chromospheric 3-minute oscillations in disk-integrated EUV irradiance observations during a solar flare. A wavelet analysis of detrended Lyman-alpha (from GOES/EUVS) and Lyman continuum (from SDO/EVE) emission from the 2011 February 15 X-class flare revealed a 3-minute period present during the flare's main phase. The formation temperature of this emission locates this radiation to the flare's chromospheric footpoints, and similar behaviour is found in the SDO/AIA 1600A and 1700A channels, which are dominated by chromospheric continuum. The implication is that the chromosphere responds dynamically at its acoustic cutoff frequency to an impulsive injection of energy. Since the 3-minute period was not found at hard X-ray energies (50-100 keV) in RHESSI data we can state that this 3-minute oscillation does not depend on the rate of energization of, or energy deposition by, non-thermal electrons. However, a second period of 120 s found in both hard X-ray and chromospheric emission is consistent with episodic electron energization on 2-minute timescales. Our finding on the 3-minute oscillation suggests that chromospheric mechanical energy should be included in the flare energy budget, and the fluctuations in the Lyman-alpha line may influence the composition and dynamics of planetary atmospheres during periods of high activity.

  1. CMU DeepLens: deep learning for automatic image-based galaxy-galaxy strong lens finding

    Science.gov (United States)

    Lanusse, François; Ma, Quanbin; Li, Nan; Collett, Thomas E.; Li, Chun-Liang; Ravanbakhsh, Siamak; Mandelbaum, Rachel; Póczos, Barnabás

    2018-01-01

    Galaxy-scale strong gravitational lensing can not only provide a valuable probe of the dark matter distribution of massive galaxies, but also provide valuable cosmological constraints, either by studying the population of strong lenses or by measuring time delays in lensed quasars. Due to the rarity of galaxy-scale strongly lensed systems, fast and reliable automated lens finding methods will be essential in the era of large surveys such as Large Synoptic Survey Telescope, Euclid and Wide-Field Infrared Survey Telescope. To tackle this challenge, we introduce CMU DeepLens, a new fully automated galaxy-galaxy lens finding method based on deep learning. This supervised machine learning approach does not require any tuning after the training step which only requires realistic image simulations of strongly lensed systems. We train and validate our model on a set of 20 000 LSST-like mock observations including a range of lensed systems of various sizes and signal-to-noise ratios (S/N). We find on our simulated data set that for a rejection rate of non-lenses of 99 per cent, a completeness of 90 per cent can be achieved for lenses with Einstein radii larger than 1.4 arcsec and S/N larger than 20 on individual g-band LSST exposures. Finally, we emphasize the importance of realistically complex simulations for training such machine learning methods by demonstrating that the performance of models of significantly different complexities cannot be distinguished on simpler simulations. We make our code publicly available at https://github.com/McWilliamsCenter/CMUDeepLens.

  2. A simple technique of intraocular lenses explantation for single-piece foldable lenses

    Directory of Open Access Journals (Sweden)

    Arup Bhaumik

    2017-01-01

    Full Text Available Foldable intraocular lenses (IOLs are most commonly used in modern-day cataract surgery. Explantation of these IOLs is not frequently encountered, but sometimes extreme situations may demand the same. Commonly explantation is achieved by bisecting the IOL inside the anterior chamber with a cutter and delivering the pieces out one by one. This may require corneal wound extension with associated damage and endothelial loss leading to visual deterioration. We devised a simple, innovative IOL explantation technique utilizing a modified Alcon A cartridge and snare. This can successfully refold the IOL to be explanted inside the eye and deliver it out through the same wound. The device has limitations with very thick optic lenses, multipiece, and silicon IOLs. In conclusion, we describe a simple, innovative, and reproducible technique to explant almost any single piece IOL without compromising the original surgery and yielding very satisfactory outcomes.

  3. Constraints on small-scale cosmological fluctuations from SNe lensing dispersion

    International Nuclear Information System (INIS)

    Ben-Dayan, Ido; Takahashi, Ryuichi

    2015-04-01

    We provide predictions on small-scale cosmological density power spectrum from supernova lensing dispersion. Parameterizing the primordial power spectrum with running α and running of running β of the spectral index, we exclude large positive α and β parameters which induce too large lensing dispersions over current observational upper bound. We ran cosmological N-body simulations of collisionless dark matter particles to investigate non-linear evolution of the primordial power spectrum with positive running parameters. The initial small-scale enhancement of the power spectrum is largely erased when entering into the non-linear regime. For example, even if the linear power spectrum at k>10 hMpc -1 is enhanced by 1-2 orders of magnitude, the enhancement much decreases to a factor of 2-3 at late time (z≤1.5). Therefore, the lensing dispersion induced by the dark matter fluctuations weakly constrains the running parameters. When including baryon-cooling effects (which strongly enhance the small-scale clustering), the constraint is comparable or tighter than the PLANCK constraint, depending on the UV cut-off. Further investigations of the non-linear matter spectrum with baryonic processes is needed to reach a firm constraint.

  4. A Statistical Study of Multiply Imaged Systems in the Lensing Cluster Abell 68

    Science.gov (United States)

    Richard, Johan; Kneib, Jean-Paul; Jullo, Eric; Covone, Giovanni; Limousin, Marceau; Ellis, Richard; Stark, Daniel; Bundy, Kevin; Czoske, Oliver; Ebeling, Harald; Soucail, Geneviève

    2007-06-01

    We have carried out an extensive spectroscopic survey with the Keck and VLT telescopes, targeting lensed galaxies in the background of the massive cluster Abell 68. Spectroscopic measurements are obtained for 26 lensed images, including a distant galaxy at z=5.4. Redshifts have been determined for 5 out of 7 multiple-image systems. Through a careful modeling of the mass distribution in the strongly lensed regime, we derive a mass estimate of 5.3×1014 Msolar within 500 kpc. Our mass model is then used to constrain the redshift distribution of the remaining multiply imaged and singly imaged sources. This enables us to examine the physical properties for a subsample of 7 Lyα emitters at 1.7financial support of the W. M. Keck Foundation. Also based on observations collected at the Very Large Telescope (Antu/UT1 and Melipal/UT3), European Southern Observatory, Paranal, Chile (ESO programs 070.A-0643 and 073.A-0774), the NASA/ESA Hubble Space Telescope (program 8249) obtained at the Space Telescope Science Institute, which is operated by AURA under NASA contract NAS5-26555, and the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

  5. DISCOVERY OF THE LARGEST KNOWN LENSED IMAGES FORMED BY A CRITICALLY CONVERGENT LENSING CLUSTER

    International Nuclear Information System (INIS)

    Zitrin, Adi; Broadhurst, Tom

    2009-01-01

    We identify the largest known lensed images of a single spiral galaxy, lying close to the center of the distant cluster MACS J1149.5+2223 (z = 0.544). These images cover a total area of ≅150 mbox '' and are magnified ≅200 times. Unusually, there is very little image distortion, implying that the central mass distribution is almost uniform over a wide area (r ≅ 200 kpc) with a surface density equal to the critical density for lensing, corresponding to maximal lens magnification. Many fainter multiply lensed galaxies are also uncovered by our model, outlining a very large tangential critical curve, of radius r ≅ 170 kpc, posing a potential challenge for the standard LCDM cosmology. Because of the uniform central mass distribution, a particularly clean measurement of the mass of the brightest cluster galaxy is possible here, for which we infer stars contribute most of the mass within a limiting radius of ≅30 kpc, with a mass-to-light ratio of M/L B ≅ 4.5(M/L) sun . This cluster with its uniform and central mass distribution acts analogously to a regular magnifying glass, converging light without distorting the images, resulting in the most powerful lens yet discovered for accessing the faint high-z universe.

  6. Lensing reconstruction from a patchwork of polarization maps

    International Nuclear Information System (INIS)

    Namikawa, Toshiya; Nagata, Ryo

    2014-01-01

    The lensing signals involved in CMB polarization maps have already been measured with ground-based experiments such as SPTpol and POLARBEAR, and would become important as a probe of cosmological and astrophysical issues in the near future. Sizes of polarization maps from ground-based experiments are, however, limited by contamination of long wavelength modes of observational noise. To further extract the lensing signals, we explore feasibility of measuring lensing signals from a collection of small sky maps each of which is observed separately by a ground-based large telescope, i.e., lensing reconstruction from a patchwork map of large sky coverage organized from small sky patches. We show that, although the B-mode power spectrum obtained from the patchwork map is biased due to baseline uncertainty, bias on the lensing potential would be negligible if the B-mode on scales larger than the blowup scale of 1/f noise is removed in the lensing reconstruction. As examples of cosmological applications, we also show 1) the cross-correlations between the reconstructed lensing potential and full-sky temperature/polarization maps from satellite missions such as PLANCK and LiteBIRD, and 2) the use of the reconstructed potential for delensing B-mode polarization of LiteBIRD observation

  7. Weak lensing cosmology beyond ΛCDM

    International Nuclear Information System (INIS)

    Das, Sudeep; Linder, Eric V.; Nakajima, Reiko; Putter, Roland de

    2012-01-01

    Weak gravitational lensing is one of the key probes of the cosmological model, dark energy, and dark matter, providing insight into both the cosmic expansion history and large scale structure growth history. Taking into account a broad spectrum of physics affecting growth — dynamical dark energy, extended gravity, neutrino masses, and spatial curvature — we analyze the cosmological constraints. Similarly we consider the effects of a range of systematic uncertainties, in shear measurement, photometric redshifts, intrinsic alignments, and the nonlinear power spectrum, on cosmological parameter extraction. We also investigate, and provide fitting formulas for, the influence of survey parameters such as redshift depth, galaxy number densities, and sky area on the cosmological constraints in the beyond-ΛCDM parameter space. Finally, we examine the robustness of results for different fiducial cosmologies

  8. Axial nonimaging characteristics of imaging lenses: discussion.

    Science.gov (United States)

    Siew, Ronian

    2016-05-01

    At observation planes away from the image plane, an imaging lens is a nonimaging optic. We examine the variation of axial irradiance with distance in image space and highlight the following little-known observation for discussion: On a per-unit-area basis, the position of the highest concentration in image space is generally not at the focal plane. This characteristic is contrary to common experience, and it offers an additional degree of freedom for the design of detection systems. Additionally, it would also apply to lenses with negative refractive index. The position of peak concentration and its irradiance is dependent upon the location and irradiance of the image. As such, this discussion also includes a close examination of expressions for image irradiance and explains how they are related to irradiance calculations beyond the image plane. This study is restricted to rotationally symmetric refractive imaging systems with incoherent extended Lambertian sources.

  9. Microfabrication of hard x-ray lenses

    DEFF Research Database (Denmark)

    Stöhr, Frederik

    This thesis deals with the development of silicon compound refractive lenses (Si-CRLs) for shaping hard x-ray beams. The CRLs are to be fabricated using state of the art microfabrication techniques. The primary goal of the thesis work is to produce Si-CRLs with considerably increased structure...... and characterized with respect to their shape. Their optical performances were tested at the European Synchrotron Radiation Facility (ESRF). Two 1D-focusing Si-CRLs suitable as condensers in hard-XRM were developed utilizing the aforementioned two different strategies. The first Si-condenser showed focusing of a 56...... of space for sample surroundings and ensure low-divergent and wide x-ray beams with narrow waists. Both results are substantial improvements to what was available at the start of this thesis work. The challenge of making x-ray objectives in silicon by interdigitation of lenslets alternately focusing...

  10. Mechanical properties of intra-ocular lenses

    Science.gov (United States)

    Ehrmann, Klaus; Kim, Eon; Parel, Jean-Marie

    2008-02-01

    Cataract surgery usually involves the replacement of the natural crystalline lens with a rigid or foldable intraocular lens to restore clear vision for the patient. While great efforts have been placed on optimising the shape and optical characteristics of IOLs, little is know about the mechanical properties of these devices and how they interact with the capsular bag once implanted. Mechanical properties measurements were performed on 8 of the most commonly implanted IOLs using a custom build micro tensometer. Measurement data will be presented for the stiffness of the haptic elements, the buckling resistance of foldable IOLs, the dynamic behaviour of the different lens materials and the axial compressibility. The biggest difference between the lens types was found between one-piece and 3-piece lenses with respect to the flexibility of the haptic elements

  11. DETECTION OF LENSING SUBSTRUCTURE USING ALMA OBSERVATIONS OF THE DUSTY GALAXY SDP.81

    Energy Technology Data Exchange (ETDEWEB)

    Hezaveh, Yashar D.; Mao, Yao-Yuan; Morningstar, Warren; Blandford, Roger D.; Levasseur, Laurence Perreault; Wechsler, Risa H. [Kavli Institute for Particle Astrophysics and Cosmology and Department of Physics, Stanford University, 452 Lomita Mall, Stanford, CA 94305-4085 (United States); Dalal, Neal; Wen, Di; Kemball, Athol; Vieira, Joaquin D. [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana IL 61801 (United States); Marrone, Daniel P. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Carlstrom, John E. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Fassnacht, Christopher D. [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Holder, Gilbert P. [Department of Physics, McGill University, 3600 Rue University, Montreal, Quebec H3A 2T8 (Canada); Marshall, Philip J. [Kavli Institute for Particle Astrophysics and Cosmology and Department of Particle Physics and Astrophysics, SLAC National Accelerator Laboratory, Menlo Park, CA 94305 (United States); Murray, Norman [CITA, University of Toronto, 60 St. George St., Toronto ON M5S 3H8 (Canada)

    2016-05-20

    We study the abundance of substructure in the matter density near galaxies using ALMA Science Verification observations of the strong lensing system SDP.81. We present a method to measure the abundance of subhalos around galaxies using interferometric observations of gravitational lenses. Using simulated ALMA observations we explore the effects of various systematics, including antenna phase errors and source priors, and show how such errors may be measured or marginalized. We apply our formalism to ALMA observations of SDP.81. We find evidence for the presence of a M = 10{sup 8.96±0.12} M {sub ⊙} subhalo near one of the images, with a significance of 6.9 σ in a joint fit to data from bands 6 and 7; the effect of the subhalo is also detected in both bands individually. We also derive constraints on the abundance of dark matter (DM) subhalos down to M ∼ 2 × 10{sup 7} M {sub ⊙}, pushing down to the mass regime of the smallest detected satellites in the Local Group, where there are significant discrepancies between the observed population of luminous galaxies and predicted DM subhalos. We find hints of additional substructure, warranting further study using the full SDP.81 data set (including, for example, the spectroscopic imaging of the lensed carbon monoxide emission). We compare the results of this search to the predictions of ΛCDM halos, and find that given current uncertainties in the host halo properties of SDP.81, our measurements of substructure are consistent with theoretical expectations. Observations of larger samples of gravitational lenses with ALMA should be able to improve the constraints on the abundance of galactic substructure.

  12. DETECTION OF LENSING SUBSTRUCTURE USING ALMA OBSERVATIONS OF THE DUSTY GALAXY SDP.81

    International Nuclear Information System (INIS)

    Hezaveh, Yashar D.; Mao, Yao-Yuan; Morningstar, Warren; Blandford, Roger D.; Levasseur, Laurence Perreault; Wechsler, Risa H.; Dalal, Neal; Wen, Di; Kemball, Athol; Vieira, Joaquin D.; Marrone, Daniel P.; Carlstrom, John E.; Fassnacht, Christopher D.; Holder, Gilbert P.; Marshall, Philip J.; Murray, Norman

    2016-01-01

    We study the abundance of substructure in the matter density near galaxies using ALMA Science Verification observations of the strong lensing system SDP.81. We present a method to measure the abundance of subhalos around galaxies using interferometric observations of gravitational lenses. Using simulated ALMA observations we explore the effects of various systematics, including antenna phase errors and source priors, and show how such errors may be measured or marginalized. We apply our formalism to ALMA observations of SDP.81. We find evidence for the presence of a M = 10 8.96±0.12 M ⊙ subhalo near one of the images, with a significance of 6.9 σ in a joint fit to data from bands 6 and 7; the effect of the subhalo is also detected in both bands individually. We also derive constraints on the abundance of dark matter (DM) subhalos down to M ∼ 2 × 10 7 M ⊙ , pushing down to the mass regime of the smallest detected satellites in the Local Group, where there are significant discrepancies between the observed population of luminous galaxies and predicted DM subhalos. We find hints of additional substructure, warranting further study using the full SDP.81 data set (including, for example, the spectroscopic imaging of the lensed carbon monoxide emission). We compare the results of this search to the predictions of ΛCDM halos, and find that given current uncertainties in the host halo properties of SDP.81, our measurements of substructure are consistent with theoretical expectations. Observations of larger samples of gravitational lenses with ALMA should be able to improve the constraints on the abundance of galactic substructure.

  13. AUTOMATED DETECTION OF GALAXY-SCALE GRAVITATIONAL LENSES IN HIGH-RESOLUTION IMAGING DATA

    International Nuclear Information System (INIS)

    Marshall, Philip J.; Bradac, Marusa; Hogg, David W.; Moustakas, Leonidas A.; Fassnacht, Christopher D.; Schrabback, Tim; Blandford, Roger D.

    2009-01-01

    We expect direct lens modeling to be the key to successful and meaningful automated strong galaxy-scale gravitational lens detection. We have implemented a lens-modeling 'robot' that treats every bright red galaxy (BRG) in a large imaging survey as a potential gravitational lens system. Having optimized a simple model for 'typical' galaxy-scale gravitational lenses, we generate four assessments of model quality that are then used in an automated classification. The robot infers from these four data the lens classification parameter H that a human would have assigned; the inference is performed using a probability distribution generated from a human-classified training set of candidates, including realistic simulated lenses and known false positives drawn from the Hubble Space Telescope (HST) Extended Groth Strip (EGS) survey. We compute the expected purity, completeness, and rejection rate, and find that these statistics can be optimized for a particular application by changing the prior probability distribution for H; this is equivalent to defining the robot's 'character'. Adopting a realistic prior based on expectations for the abundance of lenses, we find that a lens sample may be generated that is ∼100% pure, but only ∼20% complete. This shortfall is due primarily to the oversimplicity of the model of both the lens light and mass. With a more optimistic robot, ∼90% completeness can be achieved while rejecting ∼90% of the candidate objects. The remaining candidates must be classified by human inspectors. Displaying the images used and produced by the robot on a custom 'one-click' web interface, we are able to inspect and classify lens candidates at a rate of a few seconds per system, suggesting that a future 1000 deg. 2 imaging survey containing 10 7 BRGs, and some 10 4 lenses, could be successfully, and reproducibly, searched in a modest amount of time. We have verified our projected survey statistics, albeit at low significance, using the HST EGS data

  14. Towards an understanding of dark matter: Precise gravitational lensing analysis complemented by robust photometric redshifts

    Science.gov (United States)

    Coe, Daniel Aaron

    The goal of thesis is to help scientists resolve one of the great mysteries of our time: the nature of Dark Matter. Dark Matter is currently believed to make up over 80% of the material in our universe, yet we have so far inferred but a few of its basic properties. Here we study the Dark Matter surrounding a galaxy cluster, Abell 1689, via the most direct method currently available--gravitational lensing. Abell 1689 is a "strong" gravitational lens, meaning it produces multiple images of more distant galaxies. The observed positions of these images can be measured very precisely and act as a blueprint allowing us to reconstruct the Dark Matter distribution of the lens. Until now, such mass models of Abell 1689 have reproduced the observed multiple images well but with significant positional offsets. Using a new method we develop here, we obtain a new mass model which perfectly reproduces the observed positions of 168 knots identified within 135 multiple images of 42 galaxies. An important ingredient to our mass model is the accurate measurement of distances to the lensed galaxies via their photometric redshifts. Here we develop tools which improve the accuracy of these measurements based on our study of the Hubble Ultra Deep Field, the only image yet taken to comparable depth as the magnified regions of Abell 1689. We present results both for objects in the Hubble Ultra Deep Field and for galaxies gravitationally lensed by Abell 1689. As part of this thesis, we also provide reviews of Dark Matter and Gravitational Lensing, including a chapter devoted to the mass profiles of Dark Matter halos realized in simulations. The original work presented here was performed primarily by myself under the guidance of Narciso Benítez and Holland Ford as a member of the Advanced Camera for Surveys GTO Science Team at Johns Hopkins University and the Instituto de Astrofisica de Andalucfa. My advisors served on my thesis committee along with Rick White, Gabor Domokos, and Steve

  15. Spectroscopic Observations of Lyman Break Galaxies at Redshifts ~4, 5, and 6 in the Goods-South Field

    Science.gov (United States)

    Vanzella, E.; Giavalisco, M.; Dickinson, M.; Cristiani, S.; Nonino, M.; Kuntschner, H.; Popesso, P.; Rosati, P.; Renzini, A.; Stern, D.; Cesarsky, C.; Ferguson, H. C.; Fosbury, R. A. E.

    2009-04-01

    We report on observations of Lyman break galaxies (LBGs) selected from the Great Observatories Origins Deep Survey at mean redshifts z ~ 4, 5, and 6 (B 435-, V 606-, and i 775-band dropouts, respectively), obtained with the red-sensitive FORS2 spectrograph at the ESO VLT. This program has yielded spectroscopic identifications for 114 galaxies (~60% of the targeted sample), of which 51 are at z ~ 4, 31 at z ~ 5, and 32 at z ~ 6. We demonstrate that the adopted selection criteria are effective, identifying galaxies at the expected redshift with minimal foreground contamination. Of the 10% interlopers, 83% turn out to be Galactic stars. Once selection effects are properly accounted for, the rest-frame ultraviolet (UV) spectra of the higher redshift LBGs appear to be similar to their counterparts at z ~ 3. As at z ~ 3, LBGs at z ~ 4 and z ~ 5 are observed with Lyα both in emission and in absorption; when in absorption, strong interstellar lines are also observed in the spectra. The stacked spectra of Lyα absorbers and emitters also show that the former have redder UV spectra and stronger but narrower interstellar lines, a fact also observed at z ~ 2 and 3. At z ~ 6, sensitivity issues bias our sample toward galaxies with Lyα in emission; nevertheless, these spectra appear to be similar to their lower redshift counterparts. As in other studies at similar redshifts, we find clear evidence that brighter LBGs tend to have weaker Lyα emission lines. At fixed rest-frame UV luminosity, the equivalent width of the Lyα emission line is larger at higher redshifts. At all redshifts where the measurements can be reliably made, the redshift of the Lyα emission line turns out to be larger than that of the interstellar absorption lines (ISLs), with a median velocity difference ΔV ~ 400 km s-1 at z ~ 4 and 5, consistent with results at lower redshifts. This shows that powerful, large-scale winds are common at high redshift. In general, there is no strong correlation between the

  16. Weak lensing galaxy cluster field reconstruction

    Science.gov (United States)

    Jullo, E.; Pires, S.; Jauzac, M.; Kneib, J.-P.

    2014-02-01

    In this paper, we compare three methods to reconstruct galaxy cluster density fields with weak lensing data. The first method called FLens integrates an inpainting concept to invert the shear field with possible gaps, and a multi-scale entropy denoising procedure to remove the noise contained in the final reconstruction, that arises mostly from the random intrinsic shape of the galaxies. The second and third methods are based on a model of the density field made of a multi-scale grid of radial basis functions. In one case, the model parameters are computed with a linear inversion involving a singular value decomposition (SVD). In the other case, the model parameters are estimated using a Bayesian Monte Carlo Markov Chain optimization implemented in the lensing software LENSTOOL. Methods are compared on simulated data with varying galaxy density fields. We pay particular attention to the errors estimated with resampling. We find the multi-scale grid model optimized with Monte Carlo Markov Chain to provide the best results, but at high computational cost, especially when considering resampling. The SVD method is much faster but yields noisy maps, although this can be mitigated with resampling. The FLens method is a good compromise with fast computation, high signal-to-noise ratio reconstruction, but lower resolution maps. All three methods are applied to the MACS J0717+3745 galaxy cluster field, and reveal the filamentary structure discovered in Jauzac et al. We conclude that sensitive priors can help to get high signal-to-noise ratio, and unbiased reconstructions.

  17. Precision glass molding: Toward an optimal fabrication of optical lenses

    Science.gov (United States)

    Zhang, Liangchi; Liu, Weidong

    2017-03-01

    It is costly and time consuming to use machining processes, such as grinding, polishing and lapping, to produce optical glass lenses with complex features. Precision glass molding (PGM) has thus been developed to realize an efficient manufacture of such optical components in a single step. However, PGM faces various technical challenges. For example, a PGM process must be carried out within the super-cooled region of optical glass above its glass transition temperature, in which the material has an unstable non-equilibrium structure. Within a narrow window of allowable temperature variation, the glass viscosity can change from 105 to 1012 Pas due to the kinetic fragility of the super-cooled liquid. This makes a PGM process sensitive to its molding temperature. In addition, because of the structural relaxation in this temperature window, the atomic structure that governs the material properties is strongly dependent on time and thermal history. Such complexity often leads to residual stresses and shape distortion in a lens molded, causing unexpected changes in density and refractive index. This review will discuss some of the central issues in PGM processes and provide a method based on a manufacturing chain consideration from mold material selection, property and deformation characterization of optical glass to process optimization. The realization of such optimization is a necessary step for the Industry 4.0 of PGM.

  18. Micro-Raman analysis of glisterings in intraocular lenses

    Science.gov (United States)

    Rusciano, G.; Martinez, A.; Pesce, G.; Zito, G.; Sasso, A.

    2017-06-01

    The phenomenon of inclusions or microvacuoles in intraocular lenses (IOL), often referred to glistenings due to their appearance when visualized in slit-lamp exams, is main cause of decreased visual in people after IOL implantation. For this reason, there is a huge request by the market of new polymers able to reduce, or even eliminate, the formation of such microvacuoles. In such frame, the use of advanced optical techniques, able to provide a deeper insight on the glistering formation, is strongly required. In particular, Raman spectroscopy (RS) is ideally suited for the analysis of polymers, due to its well-know sensitivity to highly polarizable chemical groups, commonly found in the polymer chains backbones. Moreover, the combination of RS with optical microscopy (Raman micro-spectroscopy) paves the way for real, information-rich chemical mapping of polymeric materials (Raman imaging). In this paper, we analyze the formation of microvacuoles in IOLs following a thermal treatment. In particular, we performed a chemical mapping of a single microvacuole, which allowed us to infer on its effective chemical composition. In order to investigate on the reversibility of glistenings formation, this analysis was repeated as function of time after thermal treatment, in different IOL environments. It turns out that this phenomenon is partially reversible, with an almost complete disappearance of microvacuoles in a dry environment.

  19. Realization of first order optical systems using thin lenses

    International Nuclear Information System (INIS)

    Sudarshan, E.C.G.; Mukunda, N.; Simon, R.

    1983-09-01

    A first order optical system is investigated in full generality within the context of wave optics. We reduce the problem to a study of the ray transfer matrices. The simplest such systems correspond to axially symmetric propagation. Realization of such systems by centrally located lenses separated by finite distances is studied. It is shown that every axially symmetric first order system can be realized using at most three lenses. Among anisotropic systems it is proven that every symplectic ray transfer matrix, and no others, can be realized using lenses and free propagations. Suggestions for further study of the general first order system are outlined. 16 references

  20. Chromatic aberrations of electrostatic axisymmetric lenses produced by circular cylinders

    International Nuclear Information System (INIS)

    Baranova, L.A.; Ul'yanova, N.S.; Yavor, S.Ya.

    1989-01-01

    Ion beams both to test material and for technological processes have being used lately in science and technology more and more. Electrostatic lenses are used, as a rule, for such beam production. Coefficients of chromatic aberrration for a wide range of changes in lense parameters are calculated on the basis of analytical expressions to determine the potential in immerse and isolated lenses. The chromatic aberration coefficient is presented as a polynomial according to the degrees of reverse increase, that permits to calculate a circle of blurring of subject arbitrary position

  1. Central powering of the largest Lyman-α nebula is revealed by polarized radiation.

    Science.gov (United States)

    Hayes, Matthew; Scarlata, Claudia; Siana, Brian

    2011-08-17

    High-redshift Lyman-α (Lyα) blobs are extended, luminous but rare structures that seem to be associated with the highest peaks in the matter density of the Universe. Their energy output and morphology are similar to those of powerful radio galaxies, but the source of the luminosity is unclear. Some blobs are associated with ultraviolet or infrared bright galaxies, suggesting an extreme starburst event or accretion onto a central black hole. Another possibility is gas that is shock-excited by supernovae. But not all blobs are associated with galaxies, and these ones may instead be heated by gas falling into a dark-matter halo. The polarization of the Lyα emission can in principle distinguish between these options, but a previous attempt to detect this signature returned a null detection. Here we report observations of polarized Lyα from the blob LAB1 (ref. 2). Although the central region shows no measurable polarization, the polarized fraction (P) increases to ∼20 per cent at a radius of 45 kiloparsecs, forming an almost complete polarized ring. The detection of polarized radiation is inconsistent with the in situ production of Lyα photons, and we conclude that they must have been produced in the galaxies hosted within the nebula, and re-scattered by neutral hydrogen.

  2. New evidence from the Lyman-alpha forest concerning the formation of galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, A M

    1986-12-17

    A new type of survey for galaxies with z > 2 is described. The idea is to search for the spectroscopic imprint that the H1 disc of a foreground galaxy leaves on radiation emitted by a background QSO; namely, a Lyman-..cap alpha.. absorption line broadened by radiation damping. A continuing survey has revealed the presence of 15 damped L..cap alpha.. lines with redshifts between 1.8 and 2.8 in the spectra of 68 QSOs. In comparison, no more than three discs with the properties of nearby galaxies should have been detected. Furthermore, the mean column density of the 15 absorbers, = 1.4 x 10/sup 21/cm/sup -2/, is much larger than expected for the outskirts of H1 discs. The statistical and physical evidence accumulated suggests that the damped L..cap alpha.. systems are a distinct population of absorbers with properties reminiscent of H1 discs. It is concluded that the progenitors of the baryon content of nearby galaxies have been detected. The implications for theories of galaxy formations of the discovery of this damped population of absorbers are explained.

  3. Investigating the physics and environment of Lyman limit systems in cosmological simulations

    Science.gov (United States)

    Erkal, Denis

    2015-07-01

    In this work, I investigate the properties of Lyman limit systems (LLSs) using state-of-the-art zoom-in cosmological galaxy formation simulations with on the fly radiative transfer, which includes both the cosmic UV background (UVB) and local stellar sources. I compare the simulation results to observations of the incidence frequency of LLSs and the H I column density distribution function over the redshift range z = 2-5 and find good agreement. I explore the connection between LLSs and their host haloes and find that LLSs reside in haloes with a wide range of halo masses with a nearly constant covering fraction within a virial radius. Over the range z = 2-5, I find that more than half of the LLSs reside in haloes with M test a simple model which encapsulates many of their properties. I confirm that LLSs have a characteristic absorption length given by the Jeans length and that they are in photoionization equilibrium at low column densities. Finally, I investigate the self-shielding of LLSs to the UVB and explore how the non-sphericity of LLSs affects the photoionization rate at a given N_{H I}. I find that at z ≈ 3, LLSs have an optical depth of unity at a column density of ˜1018 cm-2 and that this is the column density which characterizes the onset of self-shielding.

  4. Non-LTE effects on the strength of the Lyman edge in quasar accretion disks

    Science.gov (United States)

    Stoerzer, H.; Hauschildt, P. H.; Allard, F.

    1994-01-01

    We have calculated UV/EUV (300 A which is less than or equal to lambda which is less than or equal to 1500 A) continuous energy distributions of accretion disks in the centers of active galactic nuclei (AGNs) for disk luminosities in the range 0.1 L(sub Edd) less than or equal to L(sub acc) less than 1.0 L(sub Edd) and central masses ranging from 10(exp 8) solar mass to 10(exp 9) solar mass. The vertical gas pressure structure of the disk and the disk height are obtained analytically; the temperature stratification and the resulting continuum radiation fields are calculated numerically. We have included non-Local Thermodynamic Equilibrium (LTE) effects of both the ionization equilibrium and the level populations of hydrogen and helium. We show that these non-LTE effects reduce the strength of the Lyman edge when comapred to the LTE case. In non-LTE we find that the edge can be weakly in emission or absorption for disks seen face-on, depending on the disk parameters.

  5. Eight per cent leakage of Lyman continuum photons from a compact, star-forming dwarf galaxy.

    Science.gov (United States)

    Izotov, Y I; Orlitová, I; Schaerer, D; Thuan, T X; Verhamme, A; Guseva, N G; Worseck, G

    2016-01-14

    One of the key questions in observational cosmology is the identification of the sources responsible for ionization of the Universe after the cosmic 'Dark Ages', when the baryonic matter was neutral. The currently identified distant galaxies are insufficient to fully reionize the Universe by redshift z ≈ 6 (refs 1-3), but low-mass, star-forming galaxies are thought to be responsible for the bulk of the ionizing radiation. As direct observations at high redshift are difficult for a variety of reasons, one solution is to identify local proxies of this galaxy population. Starburst galaxies at low redshifts, however, generally are opaque to Lyman continuum photons. Small escape fractions of about 1 to 3 per cent, insufficient to ionize much surrounding gas, have been detected only in three low-redshift galaxies. Here we report far-ultraviolet observations of the nearby low-mass star-forming galaxy J0925+1403. The galaxy is leaking ionizing radiation with an escape fraction of about 8 per cent. The total number of photons emitted during the starburst phase is sufficient to ionize intergalactic medium material that is about 40 times as massive as the stellar mass of the galaxy.

  6. The environment and host haloes of the brightest z ˜ 6 Lyman-break galaxies

    Science.gov (United States)

    Hatfield, P. W.; Bowler, R. A. A.; Jarvis, M. J.; Hale, C. L.

    2018-04-01

    By studying the large-scale structure of the bright high-redshift Lyman-break galaxy (LBG) population it is possible to gain an insight into the role of environment in galaxy formation physics in the early Universe. We measure the clustering of a sample of bright (-22.7 model to measure their typical halo masses. We find that the clustering amplitude and corresponding HOD fits suggests that these sources are highly biased (b ˜ 8) objects in the densest regions of the high-redshift Universe. Coupled with the observed rapid evolution of the number density of these objects, our results suggest that the shape of high luminosity end of the luminosity function is related to feedback processes or dust obscuration in the early Universe - as opposed to a scenario where these sources are predominantly rare instances of the much more numerous MUV ˜ -19 population of galaxies caught in a particularly vigorous period of star formation. There is a slight tension between the number densities and clustering measurements, which we interpret this as a signal that a refinement of the model halo bias relation at high redshifts or the incorporation of quasi-linear effects may be needed for future attempts at modelling the clustering and number counts. Finally, the difference in number density between the fields (UltraVISTA has a surface density˜1.8 times greater than UDS) is shown to be consistent with the cosmic variance implied by the clustering measurements.

  7. Emission of Lyman α radiation in H2 + H*(2s) collisions at thermal energies

    International Nuclear Information System (INIS)

    Stern, B.

    1991-01-01

    A previously-published study of the thermal-energy collision between H 2 and metastable H*(2s), which could lead to the emission of Lyman α radiation, is reconsidered to take into account possible polarization effects. The total was function of the system is expanded in terms of the molecular states of the intermediate complex H 2 * , which constitute the minimal basis of the four adiabatic states dissociating into H 2 + H*(n=2) where they are normally degenerate in energy. The results of the calculation show the existence, between three of those states, of average values of the separation distance R (R ≅ 10 atomic units) of long range (ΔR ≅ 2 au) electronic interactions which depend on the geometric form of the H 2 * molecule. From the molecular data the hypothesis of no longer considering H 2 with H*(2s) as a rigid rotator is postulated and justified, after a purely quantum mechanical treatment of the radial equations. The mean ratio of the (oscillating) polarization angular differential cross sections tot he elastic ones is found important (> ∼ 1/10). The inelastic phenomena are anticipated to be more marked in the ortho than in the para hydrogen at a low collision energy (75 meV). (15 refs., 2 tabs., 9 figs.)

  8. Low-redshift Lyman continuum leaking galaxies with high [O III]/[O II] ratios

    Science.gov (United States)

    Izotov, Y. I.; Worseck, G.; Schaerer, D.; Guseva, N. G.; Thuan, T. X.; Fricke, K. J.; Verhamme, A.; Orlitová, I.

    2018-05-01

    We present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of five star-forming galaxies at redshifts z in the range 0.2993 - 0.4317 and with high emission-line flux ratios O32 = [O III]λ5007/[O II]λ3727 ˜ 8 - 27 aiming to detect the Lyman continuum (LyC) emission. We detect LyC emission in all galaxies with the escape fractions fesc(LyC) in a range of 2 - 72 per cent. A narrow Lyα emission line with two peaks in four galaxies and with three peaks in one object is seen in medium-resolution COS spectra with a velocity separation between the peaks Vsep varying from ˜153 km s-1 to ˜ 345 km s-1. We find a general increase of the LyC escape fraction with increasing O32 and decreasing stellar mass M⋆, but with a large scatter of fesc(LyC). A tight anti-correlation is found between fesc(LyC) and Vsep making Vsep a good parameter for the indirect determination of the LyC escape fraction. We argue that one possible source driving the escape of ionizing radiation is stellar winds and radiation from hot massive stars.

  9. A Search for Lyman Break Galaxies at z>8 in the NICMOS Parallel Imaging Survey

    Science.gov (United States)

    Henry, Alaina L.; Malkan, Matthew A.; Colbert, James W.; Siana, Brian; Teplitz, Harry I.; McCarthy, Patrick; Yan, Lin

    2007-02-01

    We have selected 14 J-dropout Lyman break galaxy (LBG) candidates with J110-H160>=2.5 from the NICMOS Parallel Imaging Survey. This survey consists of 135 arcmin2 of imaging in 228 independent sight lines, reaching average 5 σ sensitivities of J110=25.8 and H160=25.6 (AB). Distinguishing these candidates from dust-reddened star-forming galaxies at z~2-3 is difficult and will require longer wavelength observations. We consider the likelihood that any J-dropout LBGs exist in this survey and find that if L*z=9.5 is significantly brighter than L*z=6 (a factor of 4), then a few J-dropout LBGs are likely. A similar increase in luminosity has been suggested by Eyles et al. and Yan et al., but the magnitude of this increase is uncertain. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with proposals 9484, 9865, and 10226.

  10. Optimizing BAO measurements with non-linear transformations of the Lyman-α forest

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xinkang; Font-Ribera, Andreu; Seljak, Uroš, E-mail: xinkang.wang@berkeley.edu, E-mail: afont@lbl.gov, E-mail: useljak@berkeley.edu [Department of Physics, University of California, South Hall Rd, Berkeley (United States)

    2015-04-01

    We explore the effect of applying a non-linear transformation to the Lyman-α forest transmitted flux F=e{sup −τ} and the ability of analytic models to predict the resulting clustering amplitude. Both the large-scale bias of the transformed field (signal) and the amplitude of small scale fluctuations (noise) can be arbitrarily modified, but we were unable to find a transformation that increases significantly the signal-to-noise ratio on large scales using Taylor expansion up to the third order. In particular, however, we achieve a 33% improvement in signal to noise for Gaussianized field in transverse direction. On the other hand, we explore an analytic model for the large-scale biasing of the Lyα forest, and present an extension of this model to describe the biasing of the transformed fields. Using hydrodynamic simulations we show that the model works best to describe the biasing with respect to velocity gradients, but is less successful in predicting the biasing with respect to large-scale density fluctuations, especially for very nonlinear transformations.

  11. Characterizing the Lyman-alpha forest flux probability distribution function using Legendre polynomials

    Science.gov (United States)

    Cieplak, Agnieszka; Slosar, Anze

    2018-01-01

    The Lyman-alpha forest has become a powerful cosmological probe at intermediate redshift. It is a highly non-linear field with much information present beyond the power spectrum. The flux probability flux distribution (PDF) in particular has been a successful probe of small scale physics. However, it is also sensitive to pixel noise, spectrum resolution, and continuum fitting, all of which lead to possible biased estimators. Here we argue that measuring the coefficients of the Legendre polynomial expansion of the PDF offers several advantages over measuring the binned values as is commonly done. Since the n-th Legendre coefficient can be expressed as a linear combination of the first n moments of the field, this allows for the coefficients to be measured in the presence of noise and allows for a clear route towards marginalization over the mean flux. Additionally, in the presence of noise, a finite number of these coefficients are well measured with a very sharp transition into noise dominance. This compresses the information into a small amount of well-measured quantities. Finally, we find that measuring fewer quasars with high signal-to-noise produces a higher amount of recoverable information.

  12. THE BIVARIATE SIZE-LUMINOSITY RELATIONS FOR LYMAN BREAK GALAXIES AT z {approx} 4-5

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Kuang-Han; Su, Jian [Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Ferguson, Henry C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Ravindranath, Swara, E-mail: kuanghan@pha.jhu.edu [The Inter-University Center for Astronomy and Astrophysics, Pune University Campus, Pune 411007, Maharashtra (India)

    2013-03-01

    We study the bivariate size-luminosity distribution of Lyman break galaxies (LBGs) selected at redshifts around 4 and 5 in GOODS and the HUDF fields. We model the size-luminosity distribution as a combination of log-normal distribution (in size) and Schechter function (in luminosity), therefore it enables a more detailed study of the selection effects. We perform extensive simulations to quantify the dropout-selection completenesses and measurement biases and uncertainties in two-dimensional size and magnitude bins, and transform the theoretical size-luminosity distribution to the expected distribution for the observed data. Using maximum-likelihood estimator, we find that the Schechter function parameters for B {sub 435}-dropouts and are consistent with the values in the literature, but the size distributions are wider than expected from the angular momentum distribution of the underlying dark matter halos. The slope of the size-luminosity (RL) relation is similar to those found for local disk galaxies, but considerably shallower than local early-type galaxies.

  13. THE BIVARIATE SIZE-LUMINOSITY RELATIONS FOR LYMAN BREAK GALAXIES AT z ∼ 4-5

    International Nuclear Information System (INIS)

    Huang, Kuang-Han; Su, Jian; Ferguson, Henry C.; Ravindranath, Swara

    2013-01-01

    We study the bivariate size-luminosity distribution of Lyman break galaxies (LBGs) selected at redshifts around 4 and 5 in GOODS and the HUDF fields. We model the size-luminosity distribution as a combination of log-normal distribution (in size) and Schechter function (in luminosity), therefore it enables a more detailed study of the selection effects. We perform extensive simulations to quantify the dropout-selection completenesses and measurement biases and uncertainties in two-dimensional size and magnitude bins, and transform the theoretical size-luminosity distribution to the expected distribution for the observed data. Using maximum-likelihood estimator, we find that the Schechter function parameters for B 435 -dropouts and are consistent with the values in the literature, but the size distributions are wider than expected from the angular momentum distribution of the underlying dark matter halos. The slope of the size-luminosity (RL) relation is similar to those found for local disk galaxies, but considerably shallower than local early-type galaxies.

  14. Detection of baryon acoustic oscillations in the Lyman-α forests of BOSS quasar spectra

    International Nuclear Information System (INIS)

    Delubac, Timothee

    2013-01-01

    Baryon acoustic oscillations (BAO) form a standard ruler that can be used to constrain different cosmological models. This thesis reports the first measurement of the BAO feature in the correlation function of the transmitted flux fraction in the Lyman-α forests of high redshift quasars. This detection uses 89322 quasar spectra measured by the Baryon Oscillation Spectroscopic Survey (BOSS) of the third generation of the Sloan Digital Sky Survey (SDSS-III). Redshift of used quasars belong to the range 2.1≤z≤3.5. A peak in the correlation function is seen at 1.043"+"0"."0"2"1_-_0_._0_2_0 times the expected BAO peak position for a concordance ΛCDM model. In addition this thesis presents a new method of quasar selection through their variability. This method is applied to the Stripe 82 region where an important number of multi-epoch photometric data is available. On this region it achieves a quasar density of 30 deg"-"2 to be compared with the 18 deg"-"2 of usual color selections. (author) [fr

  15. Low-redshift Lyman limit systems as diagnostics of cosmological inflows and outflows

    Science.gov (United States)

    Hafen, Zachary; Faucher-Giguère, Claude-André; Anglés-Alcázar, Daniel; Kereš, Dušan; Feldmann, Robert; Chan, T. K.; Quataert, Eliot; Murray, Norman; Hopkins, Philip F.

    2017-08-01

    We use cosmological hydrodynamic simulations with stellar feedback from the FIRE (Feedback In Realistic Environments) project to study the physical nature of Lyman limit systems (LLSs) at z ≤ 1. At these low redshifts, LLSs are closely associated with dense gas structures surrounding galaxies, such as galactic winds, dwarf satellites and cool inflows from the intergalactic medium. Our analysis is based on 14 zoom-in simulations covering the halo mass range Mh ≈ 109-1013 M⊙ at z = 0, which we convolve with the dark matter halo mass function to produce cosmological statistics. We find that the majority of cosmologically selected LLSs are associated with haloes in the mass range 1010 ≲ Mh ≲ 1012 M⊙. The incidence and H I column density distribution of simulated absorbers with columns in the range 10^{16.2} ≤ N_{H I} ≤ 2× 10^{20} cm-2 are consistent with observations. High-velocity outflows (with radial velocity exceeding the halo circular velocity by a factor of ≳ 2) tend to have higher metallicities ([X/H] ˜ -0.5) while very low metallicity ([X/H] standard deviation) [X/H] = -0.9 (0.4) and does not show significant evidence for bimodality, in contrast to recent observational studies, but consistent with LLSs arising from haloes with a broad range of masses and metallicities.

  16. How to estimate the 3D power spectrum of the Lyman-α forest

    Science.gov (United States)

    Font-Ribera, Andreu; McDonald, Patrick; Slosar, Anže

    2018-01-01

    We derive and numerically implement an algorithm for estimating the 3D power spectrum of the Lyman-α (Lyα) forest flux fluctuations. The algorithm exploits the unique geometry of Lyα forest data to efficiently measure the cross-spectrum between lines of sight as a function of parallel wavenumber, transverse separation and redshift. We start by approximating the global covariance matrix as block-diagonal, where only pixels from the same spectrum are correlated. We then compute the eigenvectors of the derivative of the signal covariance with respect to cross-spectrum parameters, and project the inverse-covariance-weighted spectra onto them. This acts much like a radial Fourier transform over redshift windows. The resulting cross-spectrum inference is then converted into our final product, an approximation of the likelihood for the 3D power spectrum expressed as second order Taylor expansion around a fiducial model. We demonstrate the accuracy and scalability of the algorithm and comment on possible extensions. Our algorithm will allow efficient analysis of the upcoming Dark Energy Spectroscopic Instrument dataset.

  17. Ultraviolet photometry from the orbiting astronomical observatory. XVI - The stellar Lyman-alpha absorption line

    Science.gov (United States)

    Savage, B. D.; Panek, R. J.

    1974-01-01

    The stellar Lyman-alpha line at 1216 A was observed in 29 lightly reddened stars of spectral type B2.5 to B9 by a far-UV spectrophotometer on OAO-2. The equivalent widths obtained range from 15 A at type B2.5 to 65 A at type B8; in the late-B stars, the L-alpha line removes 2 to 3% of the total stellar flux. In this sampling, the strength of the L-alpha line correlates well with measures of the Balmer discontinuity and Balmer line strengths; luminosity classification does not seem to affect the line strength. The observed line widths also agree with the predictions of Mihala's grid of non-LTE model atmospheres. In some cases, the L-alpha line influences the interstellar column densities reported in the interstellar OAO-2 L-alpha survey. Hence, these data toward lightly reddened B2 and B1.5 stars should be regarded as upper limits only.

  18. An intensity monitor for solar hydrogen Lyman-alpha radiation (TAIYO SXU)

    International Nuclear Information System (INIS)

    Oshio, Takanori; Masuoka, Toshio; Higashino, Ichiro; Watanabe, Norihiko.

    1975-01-01

    The absolute intensity of hydrogen Lyman-alpha (1216A) from the total solar disk is currently monitored by an ion chamber as a part of the satellite mission of TAIYO. The apparatus consists of an ion chamber with a special input control mask and associated electronics. The ion chamber with an MgF 2 window and filled with NO gas is sensitive to a narrow spectral band including the Lα. The special mask serves to keep the angular response of the detector constant at the elevation angle of the sun relative to the plane perpendicular to the spinning axis of the satellite within an error of the order of one percent, when the angle is within +-30 0 . A flux reducer attenuates the incident radiation upon the detector by a factor of 20 to lengthen the life of detector. The associated electronics measures the output current of the ion chamber, holds the maximum value of the output every four-second period and sends it to the telemeter. From the currently observed data, the absolute intensity of the solar Lα is 3.2 x 10 11 photons/cm 2 sec and constant within +-4.2% during the period from 24 February to 31 May, 1975. (auth.)

  19. An unusually strong Einstein ring in the radio source PKS1830-211

    International Nuclear Information System (INIS)

    Jauncey, D.L.

    1991-01-01

    RADIO observations of the strong, flat-spectrum radio source PKS1830-211 revealed a double structure, with a separation of 1 arcsec, suggesting that it might be a gravitationally lensed object. We have now obtained high-resolution radio images of PKS1830-211 from several interferometric radiotelescope networks, which show an unusual elliptical ring-like structure connecting the two brighter components. The presence of the ring, and the similarity of the two brighter spots, argue strongly that this is indeed a gravitationally lensed system, specifically an Einstein ring in which lens and lensed object are closely aligned. Although the source is close to the galactic plane, it seems that both the lens and background (lensed) object are extragalactic. This object is one hundred times brighter than either of the two previously discovered radio Einstein rings, and is among the six brightest flat-spectrum sources in the sky. Its brightness makes it a peculiar object: it must involve either a chance alignment of a lensing object with an unusually bright background source, or an alignment with a less bright object but amplified to an unusual degree. (author)

  20. Detecting particle dark matter signatures by cross-correlating γ-ray anisotropies with weak lensing

    Science.gov (United States)

    Camera, S.; Fornasa, M.; Fornengo, N.; Regis, M.

    2016-05-01

    The underlying nature of dark matter still represents one of the fundamental questions in contemporary cosmology. Although observations well agree with its description in terms of a new fundamental particle, neither direct nor indirect signatures of its particle nature have been detected so far, despite a strong experimental effort. Similarly, particle accelerators have hitherto failed at producing dark matter particles in collider physics experiments. Here, we illustrate how the cross-correlation between anisotropies in the diffuse γ-ray background and weak gravitational lensing effects represents a novel promising way in the quest of detecting particle dark matter signatures.

  1. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  2. A most useful manifestation of relativity: gravitational lenses

    International Nuclear Information System (INIS)

    Falco, Emilio E

    2005-01-01

    Gravitational lenses are scarce but extraordinary phenomena that yield a very high rate of return on observational investment. Given their scarcity, it is very impressive that since their discovery in the extragalactic realm in 1979, they have had such an enormous impact on our knowledge of the universe. Gravitational lensing is a manifestation of general relativity that has contributed to a great variety of astrophysical and cosmological studies. In the weak-field limit, lensing studies are based on well-established physics and thus offer a direct approach to study many of the currently pressing problems of astrophysics. Examples of these are the significance of dark matter and the age and size of the universe. I present a brief history of gravitational lensing and describe recent developments in fields such as searches for dark matter and studies of galaxy evolution and cosmology. The approach is non-specialized and emphasizes observational results, to reach the widest possible audience

  3. Focusing lenses for the 20-beam fusion laser, SHIVA

    International Nuclear Information System (INIS)

    O'Neal, W.C.

    1976-01-01

    The focus lens design for the 20-beam SHIVA laser fusion facility involves considerations of uniform and normal pellet illumination. The resulting requirements dictate tailored beam intensity profiles and vacuum-loaded thin lenses

  4. 'Colored' and Decorative Contact Lenses: A Prescription Is a Must

    Science.gov (United States)

    ... Safely Wear Decorative or “Colored” Contact Lenses An entertainment industry artist from American Horror Story and the ... Follow FDA on Facebook View FDA videos on YouTube View FDA photos on Flickr FDA Archive Combination ...

  5. Gravitational lenses and the cosmological evolution of quasars

    International Nuclear Information System (INIS)

    Avni, Y.

    1981-01-01

    A heuristic model for the effect of gravitational lenses on the apparent cosmological evolution of quasars is considered. The model satisfies the requirement of average flux conservation and has no net mean amplification. This requirement is shown to be numerically important in studying the effect. On the basis of the values of the evolution indicators calculated from the model, it is concluded that it is premature to assert that lensing plays an important role in affecting the apparent evolution. A qualitative, model independent observational test for the effect is suggested. The test estimates the distances where lensing is dominant. An application of this test to a complete sample of quasars indicates that lensing cannot completely account for the apparent evolution, except in an extreme situation

  6. Gravitational lensing of the CMB: A Feynman diagram approach

    Directory of Open Access Journals (Sweden)

    Elizabeth E. Jenkins

    2014-09-01

    Full Text Available We develop a Feynman diagram approach to calculating correlations of the Cosmic Microwave Background (CMB in the presence of distortions. As one application, we focus on CMB distortions due to gravitational lensing by Large Scale Structure (LSS. We study the Hu–Okamoto quadratic estimator for extracting lensing from the CMB and derive the noise of the estimator up to O(ϕ4 in the lensing potential ϕ. By identifying the diagrams responsible for the previously noted large O(ϕ4 term, we conclude that the lensing expansion does not break down. The convergence can be significantly improved by a reorganization of the ϕ expansion. Our approach makes it simple to obtain expressions for quadratic estimators based on any CMB channel, including many previously unexplored cases. We briefly discuss other applications to cosmology of this diagrammatic approach, such as distortions of the CMB due to patchy reionization, or due to Faraday rotation from primordial axion fields.

  7. Microstructured gradient-index lenses for THz photoconductive antennas

    Directory of Open Access Journals (Sweden)

    Mads Brincker

    2016-02-01

    Full Text Available A new type of substrate lens for photoconductive antennas (PCA’s based on sub-wavelength microstructuring is presented and studied theoretically by the use of Greens function integral equation methods (GFIEM’s. By etching sub-wavelength trenches into a flat substrate, the effective dielectric constant can be designed to function like a gradient index (GRIN lens. The proposed GRIN substrate lenses have sub-mm dimension, which is smaller than the dimensions of a typical hyper-hemispherical substrate lens (HSL, and could enable fabrication of arrays of closely packed PCA’s with individual lenses integrated directly into the PCA substrate. The performance of different GRIN lenses is compared to a HSL and shown to be comparable with regards to the terahertz radiation extraction efficiency, and it is shown that the collimating properties of these GRIN lenses can be tailored by changing the parameters used for microstructuring.

  8. Exploring cosmic origins with CORE: Gravitational lensing of the CMB

    Science.gov (United States)

    Challinor, A.; Allison, R.; Carron, J.; Errard, J.; Feeney, S.; Kitching, T.; Lesgourgues, J.; Lewis, A.; Zubeldía, Í.; Achucarro, A.; Ade, P.; Ashdown, M.; Ballardini, M.; Banday, A. J.; Banerji, R.; Bartlett, J.; Bartolo, N.; Basak, S.; Baumann, D.; Bersanelli, M.; Bonaldi, A.; Bonato, M.; Borrill, J.; Bouchet, F.; Boulanger, F.; Brinckmann, T.; Bucher, M.; Burigana, C.; Buzzelli, A.; Cai, Z.-Y.; Calvo, M.; Carvalho, C.-S.; Castellano, G.; Chluba, J.; Clesse, S.; Colantoni, I.; Coppolecchia, A.; Crook, M.; d'Alessandro, G.; de Bernardis, P.; de Gasperis, G.; De Zotti, G.; Delabrouille, J.; Di Valentino, E.; Diego, J.-M.; Fernandez-Cobos, R.; Ferraro, S.; Finelli, F.; Forastieri, F.; Galli, S.; Genova-Santos, R.; Gerbino, M.; González-Nuevo, J.; Grandis, S.; Greenslade, J.; Hagstotz, S.; Hanany, S.; Handley, W.; Hernandez-Monteagudo, C.; Hervías-Caimapo, C.; Hills, M.; Hivon, E.; Kiiveri, K.; Kisner, T.; Kunz, M.; Kurki-Suonio, H.; Lamagna, L.; Lasenby, A.; Lattanzi, M.; Liguori, M.; Lindholm, V.; López-Caniego, M.; Luzzi, G.; Maffei, B.; Martinez-González, E.; Martins, C. J. A. P.; Masi, S.; Matarrese, S.; McCarthy, D.; Melchiorri, A.; Melin, J.-B.; Molinari, D.; Monfardini, A.; Natoli, P.; Negrello, M.; Notari, A.; Paiella, A.; Paoletti, D.; Patanchon, G.; Piat, M.; Pisano, G.; Polastri, L.; Polenta, G.; Pollo, A.; Poulin, V.; Quartin, M.; Remazeilles, M.; Roman, M.; Rubino-Martin, J.-A.; Salvati, L.; Tartari, A.; Tomasi, M.; Tramonte, D.; Trappe, N.; Trombetti, T.; Tucker, C.; Valiviita, J.; Van de Weijgaert, R.; van Tent, B.; Vennin, V.; Vielva, P.; Vittorio, N.; Young, K.; Zannoni, M.

    2018-04-01

    Lensing of the cosmic microwave background (CMB) is now a well-developed probe of the clustering of the large-scale mass distribution over a broad range of redshifts. By exploiting the non-Gaussian imprints of lensing in the polarization of the CMB, the CORE mission will allow production of a clean map of the lensing deflections over nearly the full-sky. The number of high-S/N modes in this map will exceed current CMB lensing maps by a factor of 40, and the measurement will be sample-variance limited on all scales where linear theory is valid. Here, we summarise this mission product and discuss the science that will follow from its power spectrum and the cross-correlation with other clustering data. For example, the summed mass of neutrinos will be determined to an accuracy of 17 meV combining CORE lensing and CMB two-point information with contemporaneous measurements of the baryon acoustic oscillation feature in the clustering of galaxies, three times smaller than the minimum total mass allowed by neutrino oscillation measurements. Lensing has applications across many other science goals of CORE, including the search for B-mode polarization from primordial gravitational waves. Here, lens-induced B-modes will dominate over instrument noise, limiting constraints on the power spectrum amplitude of primordial gravitational waves. With lensing reconstructed by CORE, one can "delens" the observed polarization internally, reducing the lensing B-mode power by 60 %. This can be improved to 70 % by combining lensing and measurements of the cosmic infrared background from CORE, leading to an improvement of a factor of 2.5 in the error on the amplitude of primordial gravitational waves compared to no delensing (in the null hypothesis of no primordial B-modes). Lensing measurements from CORE will allow calibration of the halo masses of the tens of thousands of galaxy clusters that it will find, with constraints dominated by the clean polarization-based estimators. The 19

  9. Accounting for Cosmic Variance in Studies of Gravitationally Lensed High-redshift Galaxies in the Hubble Frontier Field Clusters

    OpenAIRE

    Robertson, Brant E.; Ellis, Richard S.; Dunlop, James S.; McLure, Ross J.; Stark, Dan P.; McLeod, Derek

    2014-01-01

    Strong gravitational lensing provides a powerful means for studying faint galaxies in the distant universe. By magnifying the apparent brightness of background sources, massive clusters enable the detection of galaxies fainter than the usual sensitivity limit for blank fields. However, this gain in effective sensitivity comes at the cost of a reduced survey volume and, in this Letter, we demonstrate that there is an associated increase in the cosmic variance uncertainty. As an example, we sho...

  10. Microfabricated rubber microscope using soft solid immersion lenses

    OpenAIRE

    Gambin, Yann; Legrand, Olivier; Quake, Stephen R.

    2006-01-01

    We show here a technique of soft lithography to microfabricate efficient solid immersion lenses (SIL) out of rubber elastomers. The light collection efficiency of a lens system is described by its numerical aperture (NA), and is critical for applications as epifluorescence microscopy [B. Herman, Fluorescence Microscopy (BIOS Scientific, Oxford/Springer, United Kingdom, 1998). While most simple lens systems have numerical apertures less than 1, the lenses described here have NA=1.25. Better pe...

  11. Direct probe of dark energy through gravitational lensing effect

    Energy Technology Data Exchange (ETDEWEB)

    He, Hong-Jian [T. D. Lee Institute, and School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang, Zhen, E-mail: hjhe@tsinghua.edu.cn, E-mail: zh.zhang@pku.edu.cn [Center for High Energy Physics, Peking University, Beijing 100871 (China)

    2017-08-01

    We show that gravitational lensing can provide a direct method to probe the nature of dark energy at astrophysical scales. For lensing system as an isolated astrophysical object, we derive the dark energy contribution to gravitational potential as a repulsive power-law term, containing a generic equation of state parameter w . We find that it generates w -dependent and position-dependent modification to the conventional light orbital equation of w =−1. With post-Newtonian approximation, we compute its direct effect for an isolated lensing system at astrophysical scales and find that the dark energy force can deflect the path of incident light rays. We demonstrate that the dark-energy-induced deflection angle Δα{sub DE}∝ M {sup (1+1/3} {sup w} {sup )} (with 1+1/3 w > 0), which increases with the lensing mass M and consistently approaches zero in the limit M → 0. This effect is distinctive because dark energy tends to diffuse the rays and generates concave lensing effect . This is in contrast to the conventional convex lensing effect caused by both visible and dark matter. Measuring such concave lensing effect can directly probe the existence and nature of dark energy. We estimate this effect and show that the current gravitational lensing experiments are sensitive to the direct probe of dark energy at astrophysical scales. For the special case w =−1, our independent study favors the previous works that the cosmological constant can affect light bending, but our prediction qualitatively and quantitatively differ from the literature, including our consistent realization of Δα{sub DE} → 0 (under 0 M → ) at the leading order.

  12. Phosphorylcholine impairs susceptibility to biofilm formation of hydrogel contact lenses.

    Science.gov (United States)

    Selan, Laura; Palma, Stefano; Scoarughi, Gian Luca; Papa, Rosanna; Veeh, Richard; Di Clemente, Daniele; Artini, Marco

    2009-01-01

    To compare silicone-hydrogel, poly(2-hydroxyethyl methacrylate) (pHEMA), and phosphorylcholine-coated (PC-C) contact lenses in terms of their susceptibility to biofilm formation by Staphylococcus epidermidis and Pseudomonas aeruginosa. Laboratory investigation. Biofilm formation on colonized test lenses was evaluated with confocal microscopy and in vitro antibiotic susceptibility assays. The results of the latter assays were compared with those performed on planktonic cultures of the same organism. For both microorganisms, sessile colonies on silicone-hydrogel and pHEMA lenses displayed lower antibiotic susceptibility than their planktonic counterparts. In contrast, the susceptibility of cultures growing on PC-C lenses was comparable with that for planktonic cultures. In particular, minimum inhibitory concentration for Tazocin (piperacillin plus tazobactam; Wyeth Pharmaceuticals, Aprilia, Italy; S. epidermidis) and gentamicin (P. aeruginosa) was identical, either in the presence of PC-C support or in planktonic cultures (Tazocin, aeruginosa) was two-fold higher for PC-C lenses (0.4 mug/ml) with respect to planktonic cultures (0.2 mug/ml). Confocal microscopy of lenses colonized for 24 hours with P. aeruginosa green fluorescent protein-expressing cells revealed a sessile colonization on silicone-hydrogel lens and a few isolated bacterial cells scattered widely over the surface of the PC-C lens. An increase in antibiotic susceptibility of bacterial cultures was associated with diminished bacterial adhesion. Our results indicate that PC-C lenses seem to be more resistant than silicone-hydrogel and pHEMA lenses to bacterial adhesion and colonization. This feature may facilitate their disinfection.

  13. Gravitational lensing by eigenvalue distributions of random matrix models

    Science.gov (United States)

    Martínez Alonso, Luis; Medina, Elena

    2018-05-01

    We propose to use eigenvalue densities of unitary random matrix ensembles as mass distributions in gravitational lensing. The corresponding lens equations reduce to algebraic equations in the complex plane which can be treated analytically. We prove that these models can be applied to describe lensing by systems of edge-on galaxies. We illustrate our analysis with the Gaussian and the quartic unitary matrix ensembles.

  14. Separating intrinsic alignment and galaxy-galaxy lensing

    International Nuclear Information System (INIS)

    Blazek, Jonathan; Seljak, Uroš; Mandelbaum, Rachel; Nakajima, Reiko

    2012-01-01

    The coherent physical alignment of galaxies is an important systematic for gravitational lensing studies as well as a probe of the physical mechanisms involved in galaxy formation and evolution. We develop a formalism for treating this intrinsic alignment (IA) in the context of galaxy-galaxy lensing and present an improved method for measuring IA contamination, which can arise when sources physically associated with the lens are placed behind the lens due to photometric redshift scatter. We apply the technique to recent Sloan Digital Sky Survey (SDSS) measurements of Luminous Red Galaxy lenses and typical ( ∼ L * ) source galaxies with photometric redshifts selected from the SDSS imaging data. Compared to previous measurements, this method has the advantage of being fully self-consistent in its treatment of the IA and lensing signals, solving for the two simultaneously. We find an IA signal consistent with zero, placing tight constraints on both the magnitude of the IA effect and its potential contamination to the lensing signal. While these constraints depend on source selection and redshift quality, the method can be applied to any measurement that uses photometric redshifts. We obtain a model-independent upper-limit of roughly 10% IA contamination for projected separations of r p ≈ 0.1–10 h −1 Mpc. With more stringent photo-z cuts and reasonable assumptions about the physics of intrinsic alignments, this upper limit is reduced to 1–2%. These limits are well below the statistical error of the current lensing measurements. Our results suggest that IA will not present intractable challenges to the next generation of galaxy-galaxy lensing experiments, and the methods presented here should continue to aid in our understanding of alignment processes and in the removal of IA from the lensing signal

  15. What is Gravitational Lensing? (LBNL Summer Lecture Series)

    Energy Technology Data Exchange (ETDEWEB)

    Leauthaud, Alexie [Univ. of California, Berkeley, CA (United States). Berkeley Center for Cosmological Physics (BCCP); Nakajima, Reiko [Univ. of California, Berkeley, CA (United States). Berkeley Center for Cosmological Physics (BCCP)

    2009-07-28

    Summer Lecture Series 2009: Gravitational lensing is explained by Einstein's general theory of relativity: galaxies and clusters of galaxies, which are very massive objects, act on spacetime by causing it to become curved. Alexie Leauthaud and Reiko Nakajima, astrophysicists with the Berkeley Center for Cosmological Physics, will discuss how scientists use gravitational lensing to investigate the nature of dark energy and dark matter in the universe.

  16. Adaptive silicone-membrane lenses: planar vs. shaped membrane

    CSIR Research Space (South Africa)

    Schneider, F

    2009-08-01

    Full Text Available Engineering, Georges-Koehler-Allee 102, Freiburg 79110, Germany florian.schneider@imtek.uni-freiburg.de ABSTRACT We compare the performance and optical quality of two types of adaptive fluidic silicone-membrane lenses. The membranes feature either a...-membrane lenses: planar vs. shaped membrane Florian Schneider1,2, Philipp Waibel2 and Ulrike Wallrabe2 1 CSIR, Materials Science and Manufacturing, PO Box 395, Pretoria 0001, South Africa 2 University of Freiburg – IMTEK, Department of Microsystems...

  17. Optical and visual performance of aspheric soft contact lenses.

    Science.gov (United States)

    Efron, Suzanne; Efron, Nathan; Morgan, Philip B

    2008-03-01

    This study was conducted to investigate whether aspheric design soft contact lenses reduce ocular aberrations and result in better visual acuity and subjective appreciation of clinical performance compared with spherical soft contact lenses. A unilateral, double-masked, randomized and controlled study was undertaken in which ocular aberrations and high and low contrast logMAR visual acuity were measured on myopic subjects who wore aspheric design (Biomedics 55 Evolution, CooperVision) and spherical design (Biomedics 55, CooperVision) soft contact lenses. Ten subjects who had about -2.00 D myopia wore -2.00 D lenses and 10 subjects who had about -5.00 D myopia wore -5.00 D lenses. Measurements were made under photopic and mesopic lighting conditions. Subjects were invited to grade comfort, vision in photopic and mesopic conditions, and overall impression with the two lens types on 100 unit visual analogue scales. There was no significant difference in high contrast or low contrast visual acuity between the two lens designs of either power under photopic or mesopic conditions. Both lens designs displayed lower levels of spherical aberration compared with the "no lens" condition under photopic and mesopic light levels (p designs. There were no statistically significant differences in subjective appreciation of clinical performance between lens designs or lens powers. At least with respect to the brand of lenses tested, the fitting of aspheric design soft contact lenses does not result in superior visual acuity, aberration control, or subjective appreciation compared with equivalent spherical design soft contact lenses.

  18. Polymer Compund Refractive Lenses for Hard X-ray Nanofocusing

    OpenAIRE

    Krywka, Christina; Last, Arndt; Marschall, Felix; Markus, Otto; Georgi, Sebastian; Mueller, Martin; Mohr, Jürgen

    2016-01-01

    Compound refractive lenses fabricated out of SU-8 negative photoresist have been used to generate a nanofocused, i.e. sub-μm sized X-ray focal spot at an X-ray nanodiffraction setup. X-ray microscopy and X-ray diffraction techniques have conceptually different demands on nanofocusing optical elements and so with the application of X-ray nanodiffraction in mind, this paper presents the results of an initial characterization of polymer lenses used as primary focusin...

  19. Bilateral spontaneous subluxation of scleral-fixated intraocular lenses.

    Science.gov (United States)

    Assia, Ehud I; Nemet, Arie; Sachs, Dani

    2002-12-01

    Two young men with primary ectopic lenses had intracapsular cataract extraction and scleral fixation of posterior chamber intraocular lenses (PC IOLs) using 10-0 polypropylene sutures tied to the IOL eyelets. Three to 9 years after implantation, spontaneous IOL vertical subluxation occurred in all 4 eyes (5 IOL loops), probably because of suture breakage. Late subluxation of a sutured IOL may occur several years after implantation. Double fixation and thicker sutures should be considered, especially in young patients.

  20. Complete super-sample lensing covariance in the response approach

    Science.gov (United States)

    Barreira, Alexandre; Krause, Elisabeth; Schmidt, Fabian

    2018-06-01

    We derive the complete super-sample covariance (SSC) of the matter and weak lensing convergence power spectra using the power spectrum response formalism to accurately describe the coupling of super- to sub-survey modes. The SSC term is completely characterized by the survey window function, the nonlinear matter power spectrum and the full first-order nonlinear power spectrum response function, which describes the response to super-survey density and tidal field perturbations. Generalized separate universe simulations can efficiently measure these responses in the nonlinear regime of structure formation, which is necessary for lensing applications. We derive the lensing SSC formulae for two cases: one under the Limber and flat-sky approximations, and a more general one that goes beyond the Limber approximation in the super-survey mode and is valid for curved sky applications. Quantitatively, we find that for sky fractions fsky ≈ 0.3 and a single source redshift at zS=1, the use of the flat-sky and Limber approximation underestimates the total SSC contribution by ≈ 10%. The contribution from super-survey tidal fields to the lensing SSC, which has not been included in cosmological analyses so far, is shown to represent about 5% of the total lensing covariance on multipoles l1,l2 gtrsim 300. The SSC is the dominant off-diagonal contribution to the total lensing covariance, making it appropriate to include these tidal terms and beyond flat-sky/Limber corrections in cosmic shear analyses.

  1. Lyman Alpha Camera for Io's SO2 atmosphere and Europa's water plumes

    Science.gov (United States)

    McEwen, Alfred S.; Sandel, Bill; Schneider, Nick

    2014-05-01

    The Student Lyman-Alpha Mapper (SLAM) was conceived for the Io Volcano Observer (IVO) mission proposal (McEwen et al., 2014) to determine the spatial and temporal variations in Io's SO2 atmosphere by recording the H Ly-α reflection over the disk (Feldman et al., 2000; Feaga et al., 2009). SO2 absorbs at H Ly-α, thereby modulating the brightness of sunlight reflected by the surface, and measures the density of the SO2 atmosphere and its variability with volcanic activity and time of day. Recently, enhancements at the Ly-α wavelength (121.57 nm) were seen near the limb of Europa and interpreted as active water plumes ~200 km high (Roth et al., 2014). We have a preliminary design for a very simple camera to image in a single bandpass at Ly-α, analogous to a simplified version of IMAGE EUV (Sandel et al. 2000). Our goal is at least 50 resolution elements across Io and/or Europa (~75 km/pixel), ~3x better than HST STIS, to be acquired at a range where the radiation noise is below 1E-4 hits/pixel/s. This goal is achieved with a Cassegrain-like telescope with a 10-cm aperture. The wavelength selection is achieved using a simple self-filtering mirror in combination with a solar-blind photocathode. A photon-counting detector based on a sealed image intensifier preserves the poisson statistics of the incoming photon flux. The intensifier window is coated with a solar-blind photocathode material (CsI). The location of each photon event is recorded by a position-sensitive anode based on crossed delay-line or wedge-and-strip technology. The sensitivity is 0.01 counts/pixel/sec/R, sufficient to estimate SO2 column abundances ranging from 1E15 to 1E17 per cm2 in a 5 min (300 sec) exposure. Sensitivity requirements to search for and image Europa plumes may be similar. Io's Ly-α brightness of ~3 kR exceeds the 0.8 kR brightness of Europa's plume reported by Roth et al. (2014), but the plume brightness is a direct measurement rather than inferring column abundance from

  2. The high-ion content and kinematics of low-redshift Lyman limit systems

    International Nuclear Information System (INIS)

    Fox, Andrew J.; Tumlinson, Jason; Bordoloi, Rongmon; Lehner, Nicolas; Howk, J. Christopher; Tripp, Todd M.; Katz, Neal; Prochaska, J. Xavier; Werk, Jessica K.; O'Meara, John M.; Oppenheimer, Benjamin D.; Davé, Romeel

    2013-01-01

    We study the high-ion content and kinematics of the circumgalactic medium around low-redshift galaxies using a sample of 23 Lyman limit systems (LLSs) at 0.08 < z < 0.93 observed with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. In Lehner et al., we recently showed that low-z LLSs have a bimodal metallicity distribution. Here we extend that analysis to search for differences between the high-ion and kinematic properties of the metal-poor and metal-rich branches. We find that metal-rich LLSs tend to show higher O VI columns and broader O VI profiles than metal-poor LLSs. The total H I line width (Δv 90 statistic) in LLSs is not correlated with metallicity, indicating that the H I kinematics alone cannot be used to distinguish inflow from outflow and gas recycling. Among the 17 LLSs with O VI detections, all but two show evidence of kinematic sub-structure, in the form of O VI-H I centroid offsets, multiple components, or both. Using various scenarios for how the metallicities in the high-ion and low-ion phases of each LLS compare, we constrain the ionized hydrogen column in the O VI phase to lie in the range log N(H II) ∼ 17.6-20. The O VI phase of LLSs is a substantial baryon reservoir, with M(high-ion) ∼ 10 8.5-10.9 (r/150 kpc) 2 M ☉ , similar to the mass in the low-ion phase. Accounting for the O VI phase approximately doubles the contribution of low-z LLSs to the cosmic baryon budget.

  3. The high-ion content and kinematics of low-redshift Lyman limit systems

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Andrew J.; Tumlinson, Jason; Bordoloi, Rongmon [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Lehner, Nicolas; Howk, J. Christopher [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Tripp, Todd M.; Katz, Neal [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Prochaska, J. Xavier; Werk, Jessica K. [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); O' Meara, John M. [Department of Physics, Saint Michael' s College, One Winooski Park, Colchester, VT 05439 (United States); Oppenheimer, Benjamin D. [Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands); Davé, Romeel, E-mail: afox@stsci.edu [University of the Western Cape, Robert Sobukwe Road, Bellville 7535 (South Africa)

    2013-12-01

    We study the high-ion content and kinematics of the circumgalactic medium around low-redshift galaxies using a sample of 23 Lyman limit systems (LLSs) at 0.08 < z < 0.93 observed with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. In Lehner et al., we recently showed that low-z LLSs have a bimodal metallicity distribution. Here we extend that analysis to search for differences between the high-ion and kinematic properties of the metal-poor and metal-rich branches. We find that metal-rich LLSs tend to show higher O VI columns and broader O VI profiles than metal-poor LLSs. The total H I line width (Δv {sub 90} statistic) in LLSs is not correlated with metallicity, indicating that the H I kinematics alone cannot be used to distinguish inflow from outflow and gas recycling. Among the 17 LLSs with O VI detections, all but two show evidence of kinematic sub-structure, in the form of O VI-H I centroid offsets, multiple components, or both. Using various scenarios for how the metallicities in the high-ion and low-ion phases of each LLS compare, we constrain the ionized hydrogen column in the O VI phase to lie in the range log N(H II) ∼ 17.6-20. The O VI phase of LLSs is a substantial baryon reservoir, with M(high-ion) ∼ 10{sup 8.5-10.9} (r/150 kpc){sup 2} M {sub ☉}, similar to the mass in the low-ion phase. Accounting for the O VI phase approximately doubles the contribution of low-z LLSs to the cosmic baryon budget.

  4. STAR FORMATION FROM DLA GAS IN THE OUTSKIRTS OF LYMAN BREAK GALAXIES AT z ∼ 3

    International Nuclear Information System (INIS)

    Rafelski, Marc; Wolfe, Arthur M.; Chen, Hsiao-Wen

    2011-01-01

    We present evidence for spatially extended low surface brightness emission around Lyman break galaxies (LBGs) in the V-band image of the Hubble Ultra Deep Field, corresponding to the z ∼ 3 rest-frame far-UV (FUV) light, which is a sensitive measure of star formation rates (SFRs). We find that the covering fraction of molecular gas at z ∼ 3 is not adequate to explain the emission in the outskirts of LBGs, while the covering fraction of neutral atomic-dominated hydrogen gas at high redshift is sufficient. We develop a theoretical framework to connect this emission around LBGs to the expected emission from neutral H I gas, i.e., damped Lyα systems (DLAs), using the Kennicutt-Schmidt (KS) relation. Working under the hypothesis that the observed FUV emission in the outskirts of LBGs is from in situ star formation in atomic-dominated hydrogen gas, the results suggest that the SFR efficiency in such gas at z ∼ 3 is between factors of 10 and 50 lower than predictions based on the local KS relation. The total SFR density in atomic-dominated gas at z ∼ 3 is constrained to be ∼10% of that observed from the inner regions of LBGs. In addition, the metals produced by in situ star formation in the outskirts of LBGs yield metallicities comparable to those of DLAs, which is a possible solution to the 'Missing Metals' problem for DLAs. Finally, the atomic-dominated gas in the outskirts of galaxies at both high and low redshifts has similar reduced SFR efficiencies and is consistent with the same power law.

  5. Absorber Model: the Halo-like model for the Lyman-α forest

    Science.gov (United States)

    Iršič, Vid; McQuinn, Matthew

    2018-04-01

    We present a semi-analytic model for the Lyman-α forest that is inspired by the Halo Model. This model is built on the absorption line decomposition of the forest. Flux correlations are decomposed into those within each absorption line (the 1-absorber term) and those between separate lines (the 2-absorber term), treating the lines as biased tracers of the underlying matter fluctuations. While the nonlinear exponential mapping between optical depth and flux requires an infinite series of moments to calculate any statistic, we show that this series can be re-summed (truncating at the desired order in the linear matter overdensity). We focus on the z=2–3 line-of-sight power spectrum. Our model finds that 1-absorber term dominates the power on all scales, with most of its contribution coming from H I columns of 1014–1015 cm‑2, while the smaller 2-absorber contribution comes from lower columns that trace overdensities of a few. The prominence of the 1-absorber correlations indicates that the line-of-sight power spectrum is shaped principally by the lines' number densities and their absorption profiles, with correlations between lines contributing to a lesser extent. We present intuitive formulae for the effective optical depth as well as the large-scale limits of 1-absorber and 2-absorber terms, which simplify to integrals over the H I column density distribution with different equivalent-width weightings. With minimalist models for the bias of absorption systems and their peculiar velocity broadening, our model predicts values for the density bias and velocity gradient bias that are consistent with those found in simulations.

  6. THE Lyα LINE PROFILES OF ULTRALUMINOUS INFRARED GALAXIES: FAST WINDS AND LYMAN CONTINUUM LEAKAGE

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Crystal L.; Wong, Joseph [Department of Physics, University of California, Santa Barbara, CA, 93106 (United States); Dijkstra, Mark [Institute of Theoretical Astrophysics, University of Oslo, Postboks 1029, 0858 Oslo (Norway); Henry, Alaina [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Soto, Kurt T. [Institute for Astronomy, Department of Physics, ETH Zurich, CH-8093 Zurich (Switzerland); Danforth, Charles W., E-mail: cmartin@physics.ucsb.edu [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO, 80309 (United States)

    2015-04-10

    We present new Hubble Space Telescope Cosmic Origins Spectrograph far-ultraviolet (far-UV) spectroscopy and Keck Echellete optical spectroscopy of 11 ultraluminous infrared galaxies (ULIRGs), a rare population of local galaxies experiencing massive gas inflows, extreme starbursts, and prominent outflows. We detect Lyα emission from eight ULIRGs and the companion to IRAS09583+4714. In contrast to the P Cygni profiles often seen in galaxy spectra, the Lyα profiles exhibit prominent, blueshifted emission out to Doppler shifts exceeding −1000 km s{sup −1} in three H ii-dominated and two AGN-dominated ULIRGs. To better understand the role of resonance scattering in shaping the Lyα line profiles, we directly compare them to non-resonant emission lines in optical spectra. We find that the line wings are already present in the intrinsic nebular spectra, and scattering merely enhances the wings relative to the line core. The Lyα attenuation (as measured in the COS aperture) ranges from that of the far-UV continuum to over 100 times more. A simple radiative transfer model suggests the Lyα photons escape through cavities which have low column densities of neutral hydrogen and become optically thin to the Lyman continuum in the most advanced mergers. We show that the properties of the highly blueshifted line wings on the Lyα and optical emission-line profiles are consistent with emission from clumps of gas condensing out of a fast, hot wind. The luminosity of the Lyα emission increases nonlinearly with the ULIRG bolometric luminosity and represents about 0.1–1% of the radiative cooling from the hot winds in the H ii-dominated ULIRGs.

  7. The Lyman alpha reference sample. II. Hubble space telescope imaging results, integrated properties, and trends

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, Matthew; Östlin, Göran; Duval, Florent; Sandberg, Andreas; Guaita, Lucia; Melinder, Jens; Rivera-Thorsen, Thøger [Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden); Adamo, Angela [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Schaerer, Daniel [Université de Toulouse, UPS-OMP, IRAP, F-31000 Toulouse (France); Verhamme, Anne; Orlitová, Ivana [Geneva Observatory, University of Geneva, 51 Chemin des Maillettes, CH-1290 Versoix (Switzerland); Mas-Hesse, J. Miguel; Otí-Floranes, Héctor [Centro de Astrobiología (CSIC-INTA), Departamento de Astrofísica, P.O. Box 78, E-28691 Villanueva de la Cañada (Spain); Cannon, John M.; Pardy, Stephen [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Atek, Hakim [Laboratoire dAstrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire, CH-1290 Sauverny (Switzerland); Kunth, Daniel [Institut d' Astrophysique de Paris, UMR 7095, CNRS and UPMC, 98 bis Bd Arago, F-75014 Paris (France); Laursen, Peter [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Herenz, E. Christian, E-mail: matthew@astro.su.se [Leibniz-Institut für Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany)

    2014-02-10

    We report new results regarding the Lyα output of galaxies, derived from the Lyman Alpha Reference Sample, and focused on Hubble Space Telescope imaging. For 14 galaxies we present intensity images in Lyα, Hα, and UV, and maps of Hα/Hβ, Lyα equivalent width (EW), and Lyα/Hα. We present Lyα and UV radial light profiles and show they are well-fitted by Sérsic profiles, but Lyα profiles show indices systematically lower than those of the UV (n ≈ 1-2 instead of ≳ 4). This reveals a general lack of the central concentration in Lyα that is ubiquitous in the UV. Photometric growth curves increase more slowly for Lyα than the far ultraviolet, showing that small apertures may underestimate the EW. For most galaxies, however, flux and EW curves flatten by radii ≈10 kpc, suggesting that if placed at high-z only a few of our galaxies would suffer from large flux losses. We compute global properties of the sample in large apertures, and show total Lyα luminosities to be independent of all other quantities. Normalized Lyα throughput, however, shows significant correlations: escape is found to be higher in galaxies of lower star formation rate, dust content, mass, and nebular quantities that suggest harder ionizing continuum and lower metallicity. Six galaxies would be selected as high-z Lyα emitters, based upon their luminosity and EW. We discuss the results in the context of high-z Lyα and UV samples. A few galaxies have EWs above 50 Å, and one shows f{sub esc}{sup Lyα} of 80%; such objects have not previously been reported at low-z.

  8. The non-linear power spectrum of the Lyman alpha forest

    International Nuclear Information System (INIS)

    Arinyo-i-Prats, Andreu; Miralda-Escudé, Jordi; Viel, Matteo; Cen, Renyue

    2015-01-01

    The Lyman alpha forest power spectrum has been measured on large scales by the BOSS survey in SDSS-III at z∼ 2.3, has been shown to agree well with linear theory predictions, and has provided the first measurement of Baryon Acoustic Oscillations at this redshift. However, the power at small scales, affected by non-linearities, has not been well examined so far. We present results from a variety of hydrodynamic simulations to predict the redshift space non-linear power spectrum of the Lyα transmission for several models, testing the dependence on resolution and box size. A new fitting formula is introduced to facilitate the comparison of our simulation results with observations and other simulations. The non-linear power spectrum has a generic shape determined by a transition scale from linear to non-linear anisotropy, and a Jeans scale below which the power drops rapidly. In addition, we predict the two linear bias factors of the Lyα forest and provide a better physical interpretation of their values and redshift evolution. The dependence of these bias factors and the non-linear power on the amplitude and slope of the primordial fluctuations power spectrum, the temperature-density relation of the intergalactic medium, and the mean Lyα transmission, as well as the redshift evolution, is investigated and discussed in detail. A preliminary comparison to the observations shows that the predicted redshift distortion parameter is in good agreement with the recent determination of Blomqvist et al., but the density bias factor is lower than observed. We make all our results publicly available in the form of tables of the non-linear power spectrum that is directly obtained from all our simulations, and parameters of our fitting formula

  9. A RESOLVED MAP OF THE INFRARED EXCESS IN A LYMAN BREAK GALAXY AT z = 3

    Energy Technology Data Exchange (ETDEWEB)

    Koprowski, M. P.; Coppin, K. E. K.; Geach, J. E.; Hine, N. K.; Smith, D. J. B.; Violino, G. [Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Bremer, M. [H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Chapman, S. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 4R2 (Canada); Davies, L. J. M. [ICRAR, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Hayashino, T. [Research Center for Neutrino Science, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Knudsen, K. K. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala (Sweden); Kubo, M.; Matsuda, Y. [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan); Lehmer, B. D. [Department of Physics, University of Arkansas, 226 Physics Building, 835 West Dickson Street, Fayetteville, AR 72701 (United States); Van der Werf, P. P. [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Yamada, T. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, 252-5210 Sagamihara, Kanagawa 252-5210 (Japan)

    2016-09-10

    We have observed the dust continuum of 10 z = 3.1 Lyman break galaxies with the Atacama Large Millimeter/submillimeter Array at ∼450 mas resolution in Band 7. We detect and resolve the 870 μ m emission in one of the targets with a flux density of S {sub 870} = 192 ± 57 μ Jy, and measure a stacked 3 σ signal of S {sub 870} = 67 ± 23 μ Jy for the remaining nine. The total infrared luminosities are L {sub 8–1000} = (8.4 ± 2.3) × 10{sup 10} L {sub ⊙} for the detection and L {sub 8–1000} = (2.9 ± 0.9) × 10{sup 10} L {sub ⊙} for the stack. With Hubble Space Telescope Advanced Camera for Surveys I -band imaging we map the rest-frame UV emission on the same scale as the dust, effectively resolving the “infrared excess” (IRX = L {sub FIR}/ L {sub UV}) in a normal galaxy at z = 3. Integrated over the galaxy we measure IRX = 0.56 ± 0.15, and the galaxy-averaged UV slope is β = −1.25 ± 0.03. This puts the galaxy a factor of ∼10 below the IRX– β relation for local starburst nuclei of Meurer et al. However, IRX varies by more than a factor of 3 across the galaxy, and we conclude that the complex relative morphology of the dust relative to UV emission is largely responsible for the scatter in the IRX– β relation at high- z . A naive application of a Meurer-like dust correction based on the UV slope would dramatically overestimate the total star formation rate, and our results support growing evidence that when integrated over the galaxy, the typical conditions in high- z star-forming galaxies are not analogous to those in the local starburst nuclei used to establish the Meurer relation.

  10. The Lyman alpha reference sample. II. Hubble space telescope imaging results, integrated properties, and trends

    International Nuclear Information System (INIS)

    Hayes, Matthew; Östlin, Göran; Duval, Florent; Sandberg, Andreas; Guaita, Lucia; Melinder, Jens; Rivera-Thorsen, Thøger; Adamo, Angela; Schaerer, Daniel; Verhamme, Anne; Orlitová, Ivana; Mas-Hesse, J. Miguel; Otí-Floranes, Héctor; Cannon, John M.; Pardy, Stephen; Atek, Hakim; Kunth, Daniel; Laursen, Peter; Herenz, E. Christian

    2014-01-01

    We report new results regarding the Lyα output of galaxies, derived from the Lyman Alpha Reference Sample, and focused on Hubble Space Telescope imaging. For 14 galaxies we present intensity images in Lyα, Hα, and UV, and maps of Hα/Hβ, Lyα equivalent width (EW), and Lyα/Hα. We present Lyα and UV radial light profiles and show they are well-fitted by Sérsic profiles, but Lyα profiles show indices systematically lower than those of the UV (n ≈ 1-2 instead of ≳ 4). This reveals a general lack of the central concentration in Lyα that is ubiquitous in the UV. Photometric growth curves increase more slowly for Lyα than the far ultraviolet, showing that small apertures may underestimate the EW. For most galaxies, however, flux and EW curves flatten by radii ≈10 kpc, suggesting that if placed at high-z only a few of our galaxies would suffer from large flux losses. We compute global properties of the sample in large apertures, and show total Lyα luminosities to be independent of all other quantities. Normalized Lyα throughput, however, shows significant correlations: escape is found to be higher in galaxies of lower star formation rate, dust content, mass, and nebular quantities that suggest harder ionizing continuum and lower metallicity. Six galaxies would be selected as high-z Lyα emitters, based upon their luminosity and EW. We discuss the results in the context of high-z Lyα and UV samples. A few galaxies have EWs above 50 Å, and one shows f esc Lyα of 80%; such objects have not previously been reported at low-z.

  11. High resolution transmission imaging without lenses

    International Nuclear Information System (INIS)

    Rodenburg, J M; Hurst, A C; Maiden, A

    2010-01-01

    The whole history of transmission imaging has been dominated by the lens, whether used in visible-light optics, electron optics or X-ray optics. Lenses can be thought of as a very efficient method of processing a wave front scattered from an object into an image of that object. An alternative approach is to undertake this image-formation process using a computational technique. The crudest scattering experiment is to simply record the intensity of a diffraction pattern. Recent progress in so-called diffractive imaging has shown that it is possible to recover the phase of a scattered wavefield from its diffraction pattern alone, as long as the object (or the illumination on the object) is of finite extent. In this paper we present results from a very efficient phase retrieval method which can image infinitely large fields of view. It may have important applications in improving resolution in electron microscopy, or at least allowing low specification microscopes to achieve resolution comparable to state-of-the-art machines.

  12. Extreme depth-of-field intraocular lenses

    Science.gov (United States)

    Baker, Kenneth M.

    1996-05-01

    A new technology brings the full aperture single vision pseudophakic eye's effective hyperfocal distance within the half-meter range. A modulated index IOL containing a subsurface zeroth order coherent microlenticular mosaic defined by an index gradient adds a normalizing function to the vergences or parallactic angles of incoming light rays subtended from field object points and redirects them, in the case of near-