WorldWideScience

Sample records for lensed background galaxies

  1. Detecting Gravitational Lensing of the Cosmic Microwave Background by Galaxy Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Eric Jones [Univ. of Chicago, IL (United States)

    2014-08-01

    Clusters of galaxies gravitationally lens the Cosmic Microwave Background (CMB) leading to a distinct signal in the CMB on arcminute scales. Measurement of the cluster lensing effect offers the exciting possibility of constraining the masses of galaxy clusters using CMB data alone. Improved constraints on cluster masses are in turn essential to the use of clusters as cosmological probes: uncertainties in cluster masses are currently the dominant systematic affecting cluster abundance constraints on cosmology. To date, however, the CMB cluster lensing signal remains undetected because of its small magnitude and angular size. In this thesis, we develop a maximum likelihood approach to extracting the signal from CMB temperature data. We validate the technique by applying it to mock data designed to replicate as closely as possible real data from the South Pole Telescope’s (SPT) Sunyaev-Zel’dovich (SZ) survey: the effects of the SPT beam, transfer function, instrumental noise and cluster selection are incorporated. We consider the effects of foreground emission on the analysis and show that uncertainty in amount of foreground lensing results in a small systematic error on the lensing constraints. Additionally, we show that if unaccounted for, the SZ effect leads to unacceptably large biases on the lensing constraints and develop an approach for removing SZ contamination. The results of the mock analysis presented here suggest that a 4σ first detection of the cluster lensing effect can be achieved with current SPT-SZ data.

  2. A measurement of gravitational lensing of the cosmic microwave background by galaxy clusters using data from the south pole telescope

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, E. J.; Keisler, R.; Dodelson, S.; Aird, K. A.; Allen, S. W.; Ashby, M. L. N.; Bautz, M.; Bayliss, M.; Benson, B. A.; Bleem, L. E.; Bocquet, S.; Brodwin, M.; Carlstrom, J. E.; Chang, C. L.; Chiu, I.; Cho, H-M.; Clocchiatti, A.; Crawford, T. M.; Crites, A. T.; Desai, S.; Dietrich, J. P.; de Haan, T.; Dobbs, M. A.; Foley, R. J.; Forman, W. R.; George, E. M.; Gladders, M. D.; Gonzalez, A. H.; Halverson, N. W.; Harrington, N. L.; Hennig, C.; Hoekstra, H.; Holder, G. P.; Holzapfel, W. L.; Hou, Z.; Hrubes, J. D.; Jones, C.; Knox, L.; Lee, A. T.; Leitch, E. M.; Liu, J.; Lueker, M.; Luong-Van, D.; Mantz, A.; Marrone, D. P.; McDonald, M.; McMahon, J. J.; Meyer, S. S.; Millea, M.; Mocanu, L. M.; Murray, S. S.; Padin, S.; Pryke, C.; Reichardt, C. L.; Rest, A.; Ruhl, J. E.; Saliwanchik, B. R.; Saro, A.; Sayre, J. T.; Schaffer, K. K.; Shirokoff, E.; Song, J.; Spieler, H. G.; Stalder, B.; Stanford, S. A.; Staniszewski, Z.; Stark, A. A.; Story, K. T.; van Engelen, A.; Vanderlinde, K.; Vieira, J. D.; Vikhlinin, A.; Williamson, R.; Zahn, O.; Zenteno, A.

    2015-06-20

    Clusters of galaxies are expected to gravitationally lens the cosmic microwave background (CMB) and thereby generate a distinct signal in the CMB on arcminute scales. Measurements of this effect can be used to constrain the masses of galaxy clusters with CMB data alone. Here we present a measurement of lensing of the CMB by galaxy clusters using data from the South Pole Telescope (SPT). We develop a maximum likelihood approach to extract the CMB cluster lensing signal and validate the method on mock data. We quantify the effects on our analysis of several potential sources of systematic error and find that they generally act to reduce the best-fit cluster mass. It is estimated that this bias to lower cluster mass is roughly 0.85σ in units of the statistical error bar, although this estimate should be viewed as an upper limit. We apply our maximum likelihood technique to 513 clusters selected via their Sunyaev–Zeldovich (SZ) signatures in SPT data, and rule out the null hypothesis of no lensing at 3.1σ. The lensing-derived mass estimate for the full cluster sample is consistent with that inferred from the SZ flux: ${M}_{200,\\mathrm{lens}}={0.83}_{-0.37}^{+0.38}\\;{M}_{200,\\mathrm{SZ}}$ (68% C.L., statistical error only).

  3. Combining Galaxy-Galaxy Lensing and Galaxy Clustering

    Energy Technology Data Exchange (ETDEWEB)

    Park, Youngsoo [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Krause, Elisabeth [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Dodelson, Scott [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Jain, Bhuvnesh [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Amara, Adam [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Becker, Matt [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Bridle, Sarah [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Clampitt, Joseph [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Crocce, Martin [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Honscheid, Klaus [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Gaztanaga, Enrique [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Sanchez, Carles [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Wechsler, Risa [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-01-01

    Combining galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth rate of large scale structure, a quantity that will shed light on the mechanism driving the acceleration of the Universe. The Dark Energy Survey (DES) is a prime candidate for such an analysis, with its measurements of both the distribution of galaxies on the sky and the tangential shears of background galaxies induced by these foreground lenses. By constructing an end-to-end analysis that combines large-scale galaxy clustering and small-scale galaxy-galaxy lensing, we also forecast the potential of a combined probes analysis on DES datasets. In particular, we develop a practical approach to a DES combined probes analysis by jointly modeling the assumptions and systematics affecting the different components of the data vector, employing a shared halo model, HOD parametrization, photometric redshift errors, and shear measurement errors. Furthermore, we study the effect of external priors on different subsets of these parameters. We conclude that DES data will provide powerful constraints on the evolution of structure growth in the universe, conservatively/ optimistically constraining the growth function to 8%/4.9% with its first-year data covering 1000 square degrees, and to 4%/2.3% with its full five-year data covering 5000 square degrees.

  4. HerMES: A DEFICIT IN THE SURFACE BRIGHTNESS OF THE COSMIC INFRARED BACKGROUND DUE TO GALAXY CLUSTER GRAVITATIONAL LENSING

    International Nuclear Information System (INIS)

    Zemcov, M.; Cooray, A.; Bock, J.; Dowell, C. D.; Nguyen, H. T.; Blain, A.; Béthermin, M.; Clements, D. L.; Conley, A.; Glenn, J.; Conversi, L.; Farrah, D.; Oliver, S. J.; Roseboom, I. G.; Griffin, M.; Halpern, M.; Marsden, G.; Jullo, E.; Kneib, J.-P.; Richard, J.

    2013-01-01

    We have observed four massive galaxy clusters with the SPIRE instrument on the Herschel Space Observatory and measure a deficit of surface brightness within their central region after removing detected sources. We simulate the effects of instrumental sensitivity and resolution, the source population, and the lensing effect of the clusters to estimate the shape and amplitude of the deficit. The amplitude of the central deficit is a strong function of the surface density and flux distribution of the background sources. We find that for the current best fitting faint end number counts, and excellent lensing models, the most likely amplitude of the central deficit is the full intensity of the cosmic infrared background (CIB). Our measurement leads to a lower limit to the integrated total intensity of the CIB of I 250μm >0.69 -0.03 +0.03 (stat.) -0.06 +0.11 (sys.) MJy sr –1 , with more CIB possible from both low-redshift sources and from sources within the target clusters. It should be possible to observe this effect in existing high angular resolution data at other wavelengths where the CIB is bright, which would allow tests of models of the faint source component of the CIB.

  5. Weak Lensing by Galaxy Troughs in DES Science Verification Data

    Energy Technology Data Exchange (ETDEWEB)

    Gruen, D. [Ludwig Maximilian Univ., Munich (Germany); Max Planck Inst. for Extraterrestrial Physics, Garching (Germany). et al.

    2015-09-29

    We measure the weak lensing shear around galaxy troughs, i.e. the radial alignment of background galaxies relative to underdensities in projections of the foreground galaxy field over a wide range of redshift in Science Verification data from the Dark Energy Survey. Our detection of the shear signal is highly significant (10σ–15σ for the smallest angular scales) for troughs with the redshift range z ϵ [0.2, 0.5] of the projected galaxy field and angular diameters of 10 arcmin…1°. These measurements probe the connection between the galaxy, matter density, and convergence fields. By assuming galaxies are biased tracers of the matter density with Poissonian noise, we find agreement of our measurements with predictions in a fiducial Λ cold dark matter model. Furthermore, the prediction for the lensing signal on large trough scales is virtually independent of the details of the underlying model for the connection of galaxies and matter. Our comparison of the shear around troughs with that around cylinders with large galaxy counts is consistent with a symmetry between galaxy and matter over- and underdensities. In addition, we measure the two-point angular correlation of troughs with galaxies which, in contrast to the lensing signal, is sensitive to galaxy bias on all scales. Finally, the lensing signal of troughs and their clustering with galaxies is therefore a promising probe of the statistical properties of matter underdensities and their connection to the galaxy field.

  6. 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.

  7. Dark matter halo properties from galaxy-galaxy lensing

    International Nuclear Information System (INIS)

    Brimioulle, Fabrice

    2013-01-01

    The scientific results over the past years have shown that the Universe is by far not only composed of baryonic matter. In fact the major energy content of 72% of the Universe appears to be represented by so-called dark energy, while even from the remaining components only about one fifth is of baryonic origin, whereas 80% have to be attributed to dark matter. Originally appearing in observations of spiral galaxy rotation curves, the need for dark matter has also been verified investigating elliptical galaxies and galaxy clusters. In fact, it appears that dark matter played a major role during structure formation in the early Universe. Shortly after the Big Bang, when the matter distribution was almost homogeneous, initially very small inhomogeneities in the matter distribution formed the seeds for the gravitational collapse of the matter structures. Numerical n-body simulations, for instance, clearly indicate that the presently observable evolutionary state and complexity of the matter structure in the Universe would not have been possible without dark matter, which significantly accelerated the structure collapse due to its gravitational interaction. As dark matter does not interact electromagnetically and therefore is non-luminous but only interacts gravitationally, the gravitational lens effect provides an excellent opportunity for its detection and estimation of its amount. Weak gravitational lensing is a technique that makes use of the random orientation of the intrinsic galaxy ellipticities and thus their uniform distribution. Gravitational tidal forces introduce a coherent distortion of the background object shapes, leading to a deviation from the uniform distribution which depends on the lens galaxy properties and therefore can be used to study them. This thesis describes the galaxy-galaxy lensing analysis of 89deg 2 of optical data, observed within the CFHTLS-WIDE survey. In the framework of this thesis the data were used in order to create photometric

  8. 3C 220.3: A Radio Galaxy Lensing a Submillimeter Galaxy

    NARCIS (Netherlands)

    Haas, Martin; Leipski, Christian; Barthel, Peter; Wilkes, Belinda J.; Vegetti, Simona; Bussmann, R. Shane; Willner, S. P.; Westhues, Christian; Ashby, Matthew L. N.; Chini, Rolf; Clements, David L.; Fassnacht, Christopher D.; Horesh, Assaf; Klaas, Ulrich; Koopmans, Léon V. E.; Kuraszkiewicz, Joanna; Lagattuta, David J.; Meisenheimer, Klaus; Stern, Daniel; Wylezalek, Dominika

    2014-01-01

    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

  9. Cosmological parameter constraints from galaxy-galaxy lensing and galaxy clustering with the SDSS DR7

    Science.gov (United States)

    Mandelbaum, Rachel; Slosar, Anže; Baldauf, Tobias; Seljak, Uroš; Hirata, Christopher M.; Nakajima, Reiko; Reyes, Reinabelle; Smith, Robert E.

    2013-06-01

    Recent studies have shown that the cross-correlation coefficient between galaxies and dark matter is very close to unity on scales outside a few virial radii of galaxy haloes, independent of the details of how galaxies populate dark matter haloes. This finding makes it possible to determine the dark matter clustering from measurements of galaxy-galaxy weak lensing and galaxy clustering. We present new cosmological parameter constraints based on large-scale measurements of spectroscopic galaxy samples from the Sloan Digital Sky Survey (SDSS) data release 7. We generalize the approach of Baldauf et al. to remove small-scale information (below 2 and 4 h-1 Mpc for lensing and clustering measurements, respectively), where the cross-correlation coefficient differs from unity. We derive constraints for three galaxy samples covering 7131 deg2, containing 69 150, 62 150 and 35 088 galaxies with mean redshifts of 0.11, 0.28 and 0.40. We clearly detect scale-dependent galaxy bias for the more luminous galaxy samples, at a level consistent with theoretical expectations. When we vary both σ8 and Ωm (and marginalize over non-linear galaxy bias) in a flat Λ cold dark matter model, the best-constrained quantity is σ8(Ωm/0.25)0.57 = 0.80 ± 0.05 (1σ, stat. + sys.), where statistical and systematic errors (photometric redshift and shear calibration) have comparable contributions, and we have fixed ns = 0.96 and h = 0.7. These strong constraints on the matter clustering suggest that this method is competitive with cosmic shear in current data, while having very complementary and in some ways less serious systematics. We therefore expect that this method will play a prominent role in future weak lensing surveys. When we combine these data with Wilkinson Microwave Anisotropy Probe 7-year (WMAP7) cosmic microwave background (CMB) data, constraints on σ8, Ωm, H0, wde and ∑mν become 30-80 per cent tighter than with CMB data alone, since our data break several parameter

  10. Mapping the distribution of luminous and dark matter in strong lensing galaxies

    OpenAIRE

    Ferreras, I.; Saha, P.; Williams, L. L. R.; Burles, S.

    2007-01-01

    We present the distribution of luminous and dark matter in a set of strong lensing (early-type) galaxies. By combining two independent techniques – stellar population synthesis and gravitational lensing – we can compare the baryonic and dark matter content in these galaxies within the regions that can be probed using the images of the lensed background source. Two samples were studied, extracted from the CASTLES and SLACS surveys. The former probes a wider range of redshifts and allows us to ...

  11. GALAXY SCALE LENSES IN THE RCS2. I. FIRST CATALOG OF CANDIDATE STRONG LENSES

    Energy Technology Data Exchange (ETDEWEB)

    Anguita, T. [Centro de Astro-Ingenieria, Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago (Chile); Barrientos, L. F. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago (Chile); Gladders, M. D. [Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Avenue, Chicago, IL 60637 (United States); Faure, C. [Laboratoire d' Astrophysique, Ecole Polytechnique Federale de Lausanne (EPFL), Obervatoire de Sauverny, CH-1290 Versoix (Switzerland); Yee, H. K. C.; Gilbank, D. G. [Department of Astronomy and Astrophysics, University of Toronto, 50 St George Street, Toronto, Ontario, M5S 3H4 (Canada)

    2012-04-01

    We present the first galaxy scale lens catalog from the second Red-Sequence Cluster Survey. The catalog contains 60 lensing system candidates comprised of Luminous Red Galaxy (LRG) lenses at 0.2 {approx}< z {approx}< 0.5 surrounded by blue arcs or apparent multiple images of background sources. The catalog is a valuable complement to previous galaxy-galaxy lens catalogs as it samples an intermediate lens redshift range and is composed of bright sources and lenses that allow easy follow-up for detailed analysis. Mass and mass-to-light ratio estimates reveal that the lens galaxies are massive ( M-bar {approx} 5.5 Multiplication-Sign 10{sup 11} [M{sub Sun} h{sup -1}]) and rich in dark matter (M/L-bar{approx} 14 [M{sub Sun }/L{sub Sun ,B} h]). Even though a slight increasing trend in the mass-to-light ratio is observed from z = 0.2 to z = 0.5, current redshift and light profile measurements do not allow stringent constraints on the mass-to-light ratio evolution of LRGs.

  12. Galaxy-galaxy lensing estimators and their covariance properties

    Science.gov (United States)

    Singh, Sukhdeep; Mandelbaum, Rachel; Seljak, Uroš; Slosar, Anže; Vazquez Gonzalez, Jose

    2017-11-01

    We study the covariance properties of real space correlation function estimators - primarily galaxy-shear correlations, or galaxy-galaxy lensing - using SDSS data for both shear catalogues and lenses (specifically the BOSS LOWZ sample). Using mock catalogues of lenses and sources, we disentangle the various contributions to the covariance matrix and compare them with a simple analytical model. We show that not subtracting the lensing measurement around random points from the measurement around the lens sample is equivalent to performing the measurement using the lens density field instead of the lens overdensity field. While the measurement using the lens density field is unbiased (in the absence of systematics), its error is significantly larger due to an additional term in the covariance. Therefore, this subtraction should be performed regardless of its beneficial effects on systematics. Comparing the error estimates from data and mocks for estimators that involve the overdensity, we find that the errors are dominated by the shape noise and lens clustering, which empirically estimated covariances (jackknife and standard deviation across mocks) that are consistent with theoretical estimates, and that both the connected parts of the four-point function and the supersample covariance can be neglected for the current levels of noise. While the trade-off between different terms in the covariance depends on the survey configuration (area, source number density), the diagnostics that we use in this work should be useful for future works to test their empirically determined covariances.

  13. 3C 220.3: A radio galaxy lensing a submillimeter galaxy

    International Nuclear Information System (INIS)

    Haas, Martin; Westhues, Christian; Chini, Rolf; Leipski, Christian; Klaas, Ulrich; Meisenheimer, Klaus; Barthel, Peter; Koopmans, Léon V. E.; Wilkes, Belinda J.; Bussmann, R. Shane; Willner, S. P.; Ashby, Matthew L. N.; Kuraszkiewicz, Joanna; Vegetti, Simona; Clements, David L.; Fassnacht, Christopher D.; Horesh, Assaf; Lagattuta, David J.; Stern, Daniel; Wylezalek, Dominika

    2014-01-01

    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 i ∼8±4 M ⊙ L ⊙ −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 dust

  14. 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

  15. 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.

  16. A SEARCH FOR DISK-GALAXY LENSES IN THE SLOAN DIGITAL SKY SURVEY

    International Nuclear Information System (INIS)

    Feron, Chloe; Hjorth, Jens; Samsing, Johan; McKean, John P.

    2009-01-01

    We present the first automated spectroscopic search for disk-galaxy lenses, using the Sloan Digital Sky Survey (SDSS) database. We follow up eight gravitational lens candidates, selected among a sample of ∼40,000 candidate massive disk galaxies, using a combination of ground-based imaging and long-slit spectroscopy. We confirm two gravitational lens systems: one probable disk galaxy and one probable S0 galaxy. The remaining systems are four promising disk-galaxy lens candidates, as well as two probable gravitational lenses whose lens galaxy might be an S0 galaxy. The redshifts of the lenses are z lens ∼ 0.1. The redshift range of the background sources is z source ∼ 0.3-0.7. The systems presented here are (confirmed or candidate) galaxy-galaxy lensing systems, that is, systems where the multiple images are faint and extended, allowing an accurate determination of the lens galaxy mass and light distributions without contamination from the background galaxy. Moreover, the low redshift of the (confirmed or candidates) lens galaxies is favorable for measuring rotation points to complement the lensing study. We estimate the rest-frame total mass-to-light ratio within the Einstein radius for the two confirmed lenses: we find M tot /L I = 5.4 ± 1.5 within 3.9 ± 0.9 kpc for SDSS J081230.30+543650.9 and M tot /L I = 1.5 ± 0.9 within 1.4 ± 0.8 kpc for SDSS J145543.55+530441.2 (all in solar units). Hubble Space Telescope or adaptive optics imaging is needed to further study the systems.

  17. Galaxy bias from galaxy-galaxy lensing in the DES science verification data

    Science.gov (United States)

    Prat, J.; Sánchez, C.; Miquel, R.; Kwan, J.; Blazek, J.; Bonnett, C.; Amara, A.; Bridle, S. L.; Clampitt, J.; Crocce, M.; Fosalba, P.; Gaztanaga, E.; Giannantonio, T.; Hartley, W. G.; Jarvis, M.; MacCrann, N.; Percival, W. J.; Ross, A. J.; Sheldon, E.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Fausti Neto, A.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; Marshall, J. L.; Melchior, P.; Menanteau, F.; Nord, B.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.

    2018-01-01

    We present a measurement of galaxy-galaxy lensing around a magnitude-limited (iAB science verification (DES-SV) data. We split these lenses into three photometric-redshift bins from 0.2 to 0.8, and determine the product of the galaxy bias b and cross-correlation coefficient between the galaxy and dark matter overdensity fields r in each bin, using scales above 4 h-1 Mpc comoving, where we find the linear bias model to be valid given our current uncertainties. We compare our galaxy bias results from galaxy-galaxy lensing with those obtained from galaxy clustering and CMB lensing for the same sample of galaxies, and find our measurements to be in good agreement with those in Crocce et al., while, in the lowest redshift bin (z ∼ 0.3), they show some tension with the findings in Giannantonio et al. We measure b · r to be 0.87 ± 0.11, 1.12 ± 0.16 and 1.24 ± 0.23, respectively, for the three redshift bins of width Δz = 0.2 in the range 0.2 code to split the lens sample, TPZ, leads to changes in the measured biases at the 10-20 per cent level, but it does not alter the main conclusion of this work: when comparing with Crocce et al. we do not find strong evidence for a cross-correlation parameter significantly below one in this galaxy sample, except possibly at the lowest redshift bin (z ∼ 0.3), where we find r = 0.71 ± 0.11 when using TPZ, and 0.83 ± 0.12 with BPZ.

  18. Weak Lensing by Galaxy Clusters: from Pixels to Cosmology

    International Nuclear Information System (INIS)

    Gruen, Daniel

    2015-01-01

    The story of the origin and evolution of our Universe is told, equivalently, by space-time itself and by the structures that grow inside of it. Clusters of galaxies are the frontier of bottom-up structure formation. They are the most massive objects to have collapsed at the present epoch. By that virtue, their abundance and structural parameters are highly sensitive to the composition and evolution of the Universe. The most common probe of cluster cosmology, abundance, uses samples of clusters selected by some observable. Applying a mass-observable relation (MOR), cosmological parameters can be constrained by comparing the sample to predicted cluster abundances as a function of observable and redshift. Arguably, however, cluster probes have not yet entered the era of per cent level precision cosmology. The primary reason for this is our imperfect understanding of the MORs. The overall normalization, the slope of mass vs. observable, the redshift evolution, and the degree and correlation of intrinsic scatters of observables at fixed mass have to be constrained for interpreting abundances correctly. Mass measurement of clusters by means of the differential deflection of light from background sources in their gravitational field, i.e. weak lensing, is a powerful approach for achieving this. This thesis presents new methods for and scientific results of weak lensing measurements of clusters of galaxies. The former include, on the data reduction side, (i) the correction of CCD images for non-linear effects due to the electric fields of accumulated charges and (ii) a method for masking artifact features in sets of overlapping images of the sky by comparison to the median image. Also, (iii) I develop a method for the selection of background galaxy samples based on their color and apparent magnitude that includes a new correction for contamination with cluster member galaxies. The main scientific results are the following. (i) For the Hubble Frontier Field cluster RXC J

  19. Weak Lensing by Galaxy Clusters: from Pixels to Cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Gruen, Daniel [Ludwig Maximilian Univ., Munich (Germany)

    2015-03-11

    The story of the origin and evolution of our Universe is told, equivalently, by space-time itself and by the structures that grow inside of it. Clusters of galaxies are the frontier of bottom-up structure formation. They are the most massive objects to have collapsed at the present epoch. By that virtue, their abundance and structural parameters are highly sensitive to the composition and evolution of the Universe. The most common probe of cluster cosmology, abundance, uses samples of clusters selected by some observable. Applying a mass-observable relation (MOR), cosmological parameters can be constrained by comparing the sample to predicted cluster abundances as a function of observable and redshift. Arguably, however, cluster probes have not yet entered the era of per cent level precision cosmology. The primary reason for this is our imperfect understanding of the MORs. The overall normalization, the slope of mass vs. observable, the redshift evolution, and the degree and correlation of intrinsic scatters of observables at fixed mass have to be constrained for interpreting abundances correctly. Mass measurement of clusters by means of the differential deflection of light from background sources in their gravitational field, i.e. weak lensing, is a powerful approach for achieving this. This thesis presents new methods for and scientific results of weak lensing measurements of clusters of galaxies. The former include, on the data reduction side, (i) the correction of CCD images for non-linear effects due to the electric fields of accumulated charges and (ii) a method for masking artifact features in sets of overlapping images of the sky by comparison to the median image. Also, (iii) I develop a method for the selection of background galaxy samples based on their color and apparent magnitude that includes a new correction for contamination with cluster member galaxies. The main scientific results are the following. (i) For the Hubble Frontier Field cluster RXC J

  20. Constraining gravity at the largest scales through CMB lensing and galaxy velocities

    Science.gov (United States)

    Pullen, Anthony R.; Alam, Shadab; He, Siyu; Ho, Shirley

    2016-08-01

    We demonstrate a new method to constrain gravity on the largest cosmological scales by combining measurements of cosmic microwave background (CMB) lensing and the galaxy velocity field. EG is a statistic, constructed from a gravitational lensing tracer and a measure of velocities such as redshift-space distortions (RSD), that can discriminate between gravity models while being independent of clustering bias and σ8. While traditionally, the lensing field for EG has been probed through galaxy lensing, CMB lensing has been proposed as a more robust tracer of the lensing field for EG at higher redshifts while avoiding intrinsic alignments. We perform the largest-scale measurement of EG ever, up to 150 Mpc h-1, by cross-correlating the Planck CMB lensing map with the Sloan Digital Sky Survey III (SDSS-III) CMASS galaxy sample and combining this with our measurement of the CMASS auto-power spectrum and the RSD parameter β. We report EG(z = 0.57) = 0.243 ± 0.060 (stat) ± 0.013 (sys), a measurement in tension with the general relativity (GR) prediction at a level of 2.6σ. Note that our EG measurement deviates from GR only at scales greater than 80 Mpc h-1, scales which have not been probed by previous EG tests. Upcoming surveys, which will provide an order-of-magnitude reduction in statistical errors, can significantly constrain alternative gravity models when combined with better control of systematics.

  1. Galaxy bias from galaxy-galaxy lensing in the DES Science Verification Data

    Energy Technology Data Exchange (ETDEWEB)

    Prat, J.; et al.

    2016-09-26

    We present a measurement of galaxy-galaxy lensing around a magnitude-limited ($i_{AB} < 22.5$) sample of galaxies selected from the Dark Energy Survey Science Verification (DES-SV) data. We split these lenses into three photometric-redshift bins from 0.2 to 0.8, and determine the product of the galaxy bias $b$ and cross-correlation coefficient between the galaxy and dark matter overdensity fields $r$ in each bin, using scales above 4 Mpc/$h$ comoving, where we find the linear bias model to be valid given our current uncertainties. We compare our galaxy bias results from galaxy-galaxy lensing with those obtained from galaxy clustering (Crocce et al. 2016) and CMB lensing (Giannantonio et al. 2016) for the same sample of galaxies, and find our measurements to be in good agreement with those in Crocce et al. (2016), while, in the lowest redshift bin ($z\\sim0.3$), they show some tension with the findings in Giannantonio et al. (2016). Our results are found to be rather insensitive to a large range of systematic effects. We measure $b\\cdot r$ to be $0.87\\pm 0.11$, $1.12 \\pm 0.16$ and $1.24\\pm 0.23$, respectively for the three redshift bins of width $\\Delta z = 0.2$ in the range $0.2galaxy sample, except possibly at the lowest redshift bin ($z\\sim 0.3$), where we find $r = 0.71 \\pm 0.11$ when using TPZ, and $0.83 \\pm 0.12$ with BPZ, assuming the difference between the results from the two probes can be solely attributed to the cross-correlation parameter.

  2. Cosmological Constraints from Galaxy Clustering and Weak Lensing

    Science.gov (United States)

    Troxel, Michael; DES Collaboration

    2018-01-01

    The Dark Energy Survey (DES) is a five-year, 5000 sq. deg. observing program using the Dark Energy Camera on the 4m Blanco telescope at CTIO. I will describe the cosmological analysis of large-scale structure in the Universe using 1321 sq. deg. of data taken in the first year of DES operations. The analysis combines unprecedented measurements of weak gravitational lensing and the clustering of galaxies over the redshift range 0.2 to 1.3 to derive the most precise such cosmological constraints to date. These DES results from the low-redshift Universe are consistent with those from the cosmic microwave background (CMB) and support the standard cosmological model, LCDM. In the coming years, DES will produce significantly tighter constraints on cosmology through similar and additional analyses using observations over more than three times the sky-area and more than twice the integrated exposure time per object as these results.

  3. CLASS B 1359+ 154: Modelling Lensing by a Group of Galaxies

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... The recently discovered gravitationally lensed system CLASS B1359+154 appears to have six detectable images of a single background source at a redshift of 3.235. A group of galaxies acts as the lens, at a redshift of ∼ 1. The present work identifies two distinct, physically plausible image configurations, ...

  4. Galaxy–Galaxy Weak-lensing Measurements from SDSS. I. Image Processing and Lensing Signals

    International Nuclear Information System (INIS)

    Luo, Wentao; Yang, Xiaohu; Zhang, Jun; Tweed, Dylan; Fu, Liping; Shu, Chenggang; Mo, H. J.; Bosch, Frank C. van den; Li, Ran; Li, Nan; Liu, Xiangkun; Pan, Chuzhong; Wang, Yiran; Radovich, Mario

    2017-01-01

    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 2 between the two measurements in different luminosity bins are from 0.43 to 0.83. Larger reduced χ 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.

  5. 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.

  6. GALAXY SCALE LENSES IN THE RCS2. I. FIRST CATALOG OF CANDIDATE STRONG LENSES

    International Nuclear Information System (INIS)

    Anguita, T.; Barrientos, L. F.; Gladders, M. D.; Faure, C.; Yee, H. K. C.; Gilbank, D. G.

    2012-01-01

    We present the first galaxy scale lens catalog from the second Red-Sequence Cluster Survey. The catalog contains 60 lensing system candidates comprised of Luminous Red Galaxy (LRG) lenses at 0.2 ∼ 11 [M ☉ h –1 ]) and rich in dark matter (M/L-bar∼ 14 [M ☉ /L ☉,B h]). Even though a slight increasing trend in the mass-to-light ratio is observed from z = 0.2 to z = 0.5, current redshift and light profile measurements do not allow stringent constraints on the mass-to-light ratio evolution of LRGs.

  7. Dark Energy Survey Year 1 Results: Methodology and Projections for Joint Analysis of Galaxy Clustering, Galaxy Lensing, and CMB Lensing Two-point Functions

    Energy Technology Data Exchange (ETDEWEB)

    Giannantonio, T.; et al.

    2018-02-14

    Optical imaging surveys measure both the galaxy density and the gravitational lensing-induced shear fields across the sky. Recently, the Dark Energy Survey (DES) collaboration used a joint fit to two-point correlations between these observables to place tight constraints on cosmology (DES Collaboration et al. 2017). In this work, we develop the methodology to extend the DES Collaboration et al. (2017) analysis to include cross-correlations of the optical survey observables with gravitational lensing of the cosmic microwave background (CMB) as measured by the South Pole Telescope (SPT) and Planck. Using simulated analyses, we show how the resulting set of five two-point functions increases the robustness of the cosmological constraints to systematic errors in galaxy lensing shear calibration. Additionally, we show that contamination of the SPT+Planck CMB lensing map by the thermal Sunyaev-Zel'dovich effect is a potentially large source of systematic error for two-point function analyses, but show that it can be reduced to acceptable levels in our analysis by masking clusters of galaxies and imposing angular scale cuts on the two-point functions. The methodology developed here will be applied to the analysis of data from the DES, the SPT, and Planck in a companion work.

  8. Galaxy number counts and implications for strong lensing

    NARCIS (Netherlands)

    Fassnacht, C. D.; Koopmans, L. V. E.; Wong, K. C.

    We compare galaxy number counts in Advanced Camera for Surveys (ACS) fields containing moderate-redshift (0.2 lenses with those in two control samples: (1) the first square degree of the COSMOS survey, comprising 259 ACS fields and (2) 20 ‘pure-parallel’ fields randomly

  9. 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.

  10. 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

  11. Small-scale fluctuations in the microwave background radiation and multiple gravitational lensing

    International Nuclear Information System (INIS)

    Kashlinsky, A.

    1988-01-01

    It is shown that multiple gravitational lensing of the microwave background radiation (MBR) by static compact objects significantly attenuates small-scale fluctuations in the MBR. Gravitational lensing, by altering trajectories of MBR photons reaching an observer, leads to (phase) mixing of photons from regions with different initial fluctuations. As a result of this diffusion process the original fluctuations are damped on scales up to several arcmin. An equation that describes this process and its general solution are given. It is concluded that the present upper limits on the amplitude of the MBR fluctuations on small scales cannot constrain theories of galaxy formation. 25 references

  12. Robust covariance estimation of galaxy-galaxy weak lensing: validation and limitation of jackknife covariance

    Science.gov (United States)

    Shirasaki, Masato; Takada, Masahiro; Miyatake, Hironao; Takahashi, Ryuichi; Hamana, Takashi; Nishimichi, Takahiro; Murata, Ryoma

    2017-09-01

    We develop a method to simulate galaxy-galaxy weak lensing by utilizing all-sky, light-cone simulations and their inherent halo catalogues. Using the mock catalogue to study the error covariance matrix of galaxy-galaxy weak lensing, we compare the full covariance with the 'jackknife' (JK) covariance, the method often used in the literature that estimates the covariance from the resamples of the data itself. We show that there exists the variation of JK covariance over realizations of mock lensing measurements, while the average JK covariance over mocks can give a reasonably accurate estimation of the true covariance up to separations comparable with the size of JK subregion. The scatter in JK covariances is found to be ∼10 per cent after we subtract the lensing measurement around random points. However, the JK method tends to underestimate the covariance at the larger separations, more increasingly for a survey with a higher number density of source galaxies. We apply our method to the Sloan Digital Sky Survey (SDSS) data, and show that the 48 mock SDSS catalogues nicely reproduce the signals and the JK covariance measured from the real data. We then argue that the use of the accurate covariance, compared to the JK covariance, allows us to use the lensing signals at large scales beyond a size of the JK subregion, which contains cleaner cosmological information in the linear regime.

  13. The Weak Lensing Masses of Filaments between Luminous Red Galaxies

    Science.gov (United States)

    Epps, Seth D.; Hudson, Michael J.

    2017-07-01

    In the standard model of non-linear structure formation, a cosmic web of dark-matter-dominated filaments connects dark matter haloes. In this paper, we stack the weak lensing signal of an ensemble of filaments between groups and clusters of galaxies. Specifically, we detect the weak lensing signal, using CFHTLenS galaxy ellipticities, from stacked filaments between Sloan Digital Sky Survey (SDSS)-III/Baryon Oscillation Spectroscopic Survey luminous red galaxies (LRGs). As a control, we compare the physical LRG pairs with projected LRG pairs that are more widely separated in redshift space. We detect the excess filament mass density in the projected pairs at the 5σ level, finding a mass of (1.6 ± 0.3) × 1013 M⊙ for a stacked filament region 7.1 h-1 Mpc long and 2.5 h-1 Mpc wide. This filament signal is compared with a model based on the three-point galaxy-galaxy-convergence correlation function, as developed in Clampitt et al., yielding reasonable agreement.

  14. A COSMIC MICROWAVE BACKGROUND LENSING MASS MAP AND ITS CORRELATION WITH THE COSMIC INFRARED BACKGROUND

    Energy Technology Data Exchange (ETDEWEB)

    Holder, G. P.; De Haan, T.; Dobbs, M. A.; Dudley, J. [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada); Viero, M. P.; Bock, J. [California Institute of Technology, Pasadena, CA 91125 (United States); Zahn, O. [Berkeley Center for Cosmological Physics, Department of Physics, University of California, and Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Aird, K. A. [University of Chicago, Chicago, IL 60637 (United States); Benson, B. A.; Bhattacharya, S.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Brodwin, M. [Department of Physics and Astronomy, University of Missouri, Kansas City, MO 64110 (United States); Cho, H-M. [NIST Quantum Devices Group, Boulder, CO 80305 (United States); Conley, A. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); George, E. M. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Halverson, N. W. [Department of Astrophysical and Planetary Sciences and Department of Physics, University of Colorado, Boulder, CO 80309 (United States); and others

    2013-07-01

    We use a temperature map of the cosmic microwave background (CMB) obtained using the South Pole Telescope at 150 GHz to construct a map of the gravitational convergence to z {approx} 1100, revealing the fluctuations in the projected mass density. This map shows individual features that are significant at the {approx}4{sigma} level, providing the first image of CMB lensing convergence. We cross-correlate this map with Herschel/SPIRE maps covering 90 deg{sup 2} at wavelengths of 500, 350, and 250 {mu}m. We show that these submillimeter (submm) wavelength maps are strongly correlated with the lensing convergence map, with detection significances in each of the three submm bands ranging from 6.7{sigma} to 8.8{sigma}. We fit the measurement of the cross power spectrum assuming a simple constant bias model and infer bias factors of b = 1.3-1.8, with a statistical uncertainty of 15%, depending on the assumed model for the redshift distribution of the dusty galaxies that are contributing to the Herschel/SPIRE maps.

  15. 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.

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

    International Nuclear Information System (INIS)

    Eichner, Thomas Martin

    2013-01-01

    Vauc )/(L B )∼(5.5±1.5) (M s un)/(L s un ,B ) in the case of SDSS J1430+4105. Similar results are obtained for the central mass-to-light ratio of SDSS J1538+5817. Comparing these mass-to-light ratios with photometric estimates for the mass-to-light ratios shows the best agreement with a Salpeter IMF. Modeling extraordinary systems like SDSS J1538+5817 or SDSS J1430+4105 using a two-component approach leads to a better understanding of galaxies' central dark and luminous matter properties. We also study dark matter on intermediate scales around elliptical galaxies embedded in a cluster environment. In the galaxy cluster MACSJ1206.2-0847, we describe the rare case of a background source lensed into a giant gravitational arc and additionally distorted by several nearby cluster galaxies. These distortions allow us to constrain the total matter distribution of these galaxies beyond regions normally accessible by strong lensing or dynamical studies. We model the cluster mass distribution with an elliptical NFW profile and the cluster galaxies with two parameters for the central mass and extent of a reference halo. We assume scaling relations from the reference halo to the other member galaxies based on their observed NIR-light. We can match the observed lensed positions of 12 multiply lensed background objects at an r.m.s. level of 0.85'', and can reconstruct the surface brightness distribution of the giant arc and its counterimage to an amazing accuracy. We find the length scale where the enclosed galaxy halo mass is best constrained to be at about 5 effective radii. The velocity dispersion and halo size of a galaxy with m AB,160W =19.2 or M B,Vega =-20.7 are σ=150 kms -1 and r∼26±6 kpc. The analysis carried out in this work can be extended to other cases similar to MACSJ1206.2-0847, which constitute ideal objects for the study of total matter distributions of galaxies at intermediate scales. This closes the gap between strong lensing and dynamical studies on shorter

  17. Galaxy-Galaxy Lensing in EAGLE: comparison with data from 180 square degrees of the KiDS and GAMA surveys

    OpenAIRE

    Velliscig, Marco; Cacciato, Marcello; Hoekstra, Henk; Schaye, Joop; Heymans, Catherine; Hildebrandt, Hendrik; Loveday, Jon; Norberg, Peder; Sifón, Cristóbal; Schneider, Peter; van Uitert, Edo; Viola, Massimo; Brough, Sarah; Erben, Thomas; Holwerda, Benne W.

    2016-01-01

    We present predictions for the galaxy-galaxy lensing (GGL) profile from the EAGLE hydrodynamical cosmological simulation at redshift z = 0.18, in the spatial range 0.02 background galaxies imaged by the Kilo Degree Survey around spectroscopically confirmed foreground galaxies from the Ga...

  18. Strong lensing by fermionic dark matter in galaxies

    Science.gov (United States)

    Gómez, L. Gabriel; Argüelles, C. R.; Perlick, Volker; Rueda, J. A.; Ruffini, R.

    2016-12-01

    It has been shown that a self-gravitating system of massive keV fermions in thermodynamic equilibrium correctly describes the dark matter (DM) distribution in galactic halos (from dwarf to spiral and elliptical galaxies) and that, at the same time, it predicts a denser quantum core towards the center of the configuration. Such a quantum core, for a fermion mass in the range of 50 keV ≲m c2≲345 keV , can be an alternative interpretation of the central compact object in Sgr A*, traditionally assumed to be a black hole (BH). We present in this work the gravitational lensing properties of this novel DM configuration in nearby Milky-Way-like spiral galaxies. We describe the lensing effects of the pure DM component both on halo scales, where we compare them to the effects of the Navarro-Frenk-White and the nonsingular isothermal sphere DM models, and near the galaxy center, where we compare them with the effects of a Schwarzschild BH. For the particle mass leading to the most compact DM core, m c2≈1 02 keV , we draw the following conclusions. At distances r ≳20 pc from the center of the lens the effect of the central object on the lensing properties is negligible. However, we show that measurements of the deflection angle produced by the DM distribution in the outer region at a few kpc, together with rotation curve data, could help to discriminate between different DM models. In the inner regions 1 0-6≲r ≲20 pc , the lensing effects of a DM quantum core alternative to the BH scenario becomes a theme of an analysis of unprecedented precision which is challenging for current technological developments. We show that at distances ˜1 0-4 pc strong lensing effects, such as multiple images and Einstein rings, may occur. Large differences in the deflection angle produced by a DM central core and a central BH appear at distances r ≲1 0-6 pc ; in this regime the weak-field formalism is no longer applicable and the exact general-relativistic formula has to be used

  19. Galaxy-galaxy and galaxy-cluster lensing with the SDSS and FIRST surveys

    Science.gov (United States)

    Demetroullas, C.; Brown, M. L.

    2018-01-01

    We perform a galaxy-galaxy lensing study by correlating the shapes of ∼2.7 × 105 galaxies selected from the VLA FIRST (Faint Images of the Radio Sky at Twenty centimetres) radio survey with the positions of ∼38.5 million Sloan Digital Sky Survey (SDSS) galaxies, ∼132 000 Brightest Cluster Galaxies (BCGs) and ∼78 000 SDSS galaxies that are also detected in the VLA FIRST survey. The measurements are conducted on angular scales θ ≲ 1200 arcsec. On scales θ ≲ 200 arcsec, we find that the measurements are corrupted by residual systematic effects associated with the instrumental beam of the VLA data. Using simulations, we show that we can successfully apply a correction for these effects. Using the three lens samples (the SDSS DR10 sample, the BCG sample and the SDSS-FIRST matched object sample), we measure a tangential shear signal that is inconsistent with 0 at the 10.2σ, 3.8σ and 9σ levels, respectively. Fitting an NFW model to the detected signals, we find that the ensemble mass profile of the BCG sample agrees with the values in the literature. However, the mass profiles of the SDSS DR10 and the SDSS-FIRST matched object samples are found to be shallower and steeper than results in the literature, respectively. The best-fitting Virial masses for the SDSS DR10, BCG and SDSS-FIRST matched samples, derived using an NFW model and allowing for a varying concentration factor, are M_{200}^SDSS-DR10 = (1.2 ± 0.4) × 10^{12} M_{⊙}, M_{200}^BCG = (1.4 ± 1.3) × 10^{13} M_{⊙} and M_{200}^SDSS-FIRST =8.0 ± 4.2 × 10^{13} M_{⊙}, respectively. These results are in good agreement (within ∼2σ) with values in the literature. Our findings suggest that for galaxies to be bright both in the radio and in the optical, they must be embedded in very dense environment on scales R ≲ 1 Mpc.

  20. Evidence for Dark Energy from the Cosmic Microwave Background Alone Using the Atacama Cosmology Telescope Lensing Measurements

    Science.gov (United States)

    Sherwin, Blake D.; Dunkley, Joanna; Das, Sudeep; Appel, John W.; Bond, J. Richard; Carvalho, C. Sofia; Devlin, Mark J.; Duenner, Rolando; Essinger-Hileman, Thomas; Fowler, Joesph J.; hide

    2011-01-01

    For the first time, measurements of the cosmic microwave background radiation (CMB) alone favor cosmologies with w = -1 dark energy over models without dark energy at a 3.2-sigma level. We demonstrate this by combining the CMB lensing deflection power spectrum from the Atacama Cosmology Telescope with temperature and polarization power spectra from the "Wilkinson Microwave Anisotropy Probe. The lensing data break the geometric degeneracy of different cosmological models with similar CMB temperature power spectra. Our CMB-only measurement of the dark energy density Omega(delta) confirms other measurements from supernovae, galaxy clusters and baryon acoustic oscillations, and demonstrates the power of CMB lensing as a new cosmological tool.

  1. The dark side of galaxy colour: evidence from new SDSS measurements of galaxy clustering and lensing

    Energy Technology Data Exchange (ETDEWEB)

    Hearin, Andrew P. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States). Fermilab Center for Particle Astrophysics; Watson, Douglas F. [Univ. of Chicago, IL (United States). Kavli Inst. for Cosmological Physics (KICP); Becker, Matthew R. [Univ. of Chicago, IL (United States). Kavli Inst. for Cosmological Physics (KICP); KICP, Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Reyes, Reinabelle [Univ. of Chicago, IL (United States). Kavli Inst. for Cosmological Physics (KICP); Berlind, Andreas A. [Vanderbilt Univ., Nashville, TN (United States). Dept. of Physics and Astronomy; Zentner, Andrew R. [Pittsburgh Particle Physics, Astrophysics, and Cosmology Center (PITT PACC), PA (United States)

    2014-08-12

    The age matching model has recently been shown to predict correctly the luminosity L and g-r color of galaxies residing within dark matter halos. The central tenet of the model is intuitive: older halos tend to host galaxies with older stellar populations. In this paper, we demonstrate that age matching also correctly predicts the g-r color trends exhibited in a wide variety of statistics of the galaxy distribution for stellar mass M* threshold samples. In particular, we present new measurements of the galaxy two-point correlation function and the galaxy-galaxy lensing signal as a function of M* and g-r color from the Sloan Digital Sky Survey, and show that age matching exhibits remarkable agreement with these and other statistics of low-redshift galaxies. In so doing, we also demonstrate good agreement between the galaxy-galaxy lensing observed by SDSS and the signal predicted by abundance matching, a new success of this model. We describe how age matching is a specific example of a larger class of Conditional Abundance Matching models (CAM), a theoretical framework we introduce here for the first time. CAM provides a general formalism to study correlations at fixed mass between any galaxy property and any halo property. The striking success of our simple implementation of CAM provides compelling evidence that this technique has the potential to describe the same set of data as alternative models, but with a dramatic reduction in the required number of parameters. CAM achieves this reduction by exploiting the capability of contemporary N-body simulations to determine dark matter halo properties other than mass alone, which distinguishes our model from conventional approaches to the galaxy-halo connection.

  2. The ellipticity of galaxy cluster haloes from satellite galaxies and weak lensing

    Science.gov (United States)

    Shin, Tae-hyeon; Clampitt, Joseph; Jain, Bhuvnesh; Bernstein, Gary; Neil, Andrew; Rozo, Eduardo; Rykoff, Eli

    2018-04-01

    We study the ellipticity of galaxy cluster haloes as characterized by the distribution of cluster galaxies and as measured with weak lensing. We use Monte Carlo simulations of elliptical cluster density profiles to estimate and correct for Poisson noise bias, edge bias and projection effects. We apply our methodology to 10 428 Sloan Digital Sky Survey clusters identified by the redMaPPer algorithm with richness above 20. We find a mean ellipticity =0.271 ± 0.002 (stat) ±0.031 (sys) corresponding to an axis ratio = 0.573 ± 0.002 (stat) ±0.039 (sys). We compare this ellipticity of the satellites to the halo shape, through a stacked lensing measurement using optimal estimators of the lensing quadrupole based on Clampitt and Jain (2016). We find a best-fitting axis ratio of 0.56 ± 0.09 (stat) ±0.03 (sys), consistent with the ellipticity of the satellite distribution. Thus, cluster galaxies trace the shape of the dark matter halo to within our estimated uncertainties. Finally, we restack the satellite and lensing ellipticity measurements along the major axis of the cluster central galaxy's light distribution. From the lensing measurements, we infer a misalignment angle with an root-mean-square of 30° ± 10° when stacking on the central galaxy. We discuss applications of halo shape measurements to test the effects of the baryonic gas and active galactic nucleus feedback, as well as dark matter and gravity. The major improvements in signal-to-noise ratio expected with the ongoing Dark Energy Survey and future surveys from Large Synoptic Survey Telescope, Euclid, and Wide Field Infrared Survey Telescope will make halo shapes a useful probe of these effects.

  3. 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.

    2018-03-01

    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 8 of them demonstrating evidence of multiple images. Two of our systems are compound lens candidates, each with 2 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 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", 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.

  4. Future cosmic microwave background delensing with galaxy surveys

    Science.gov (United States)

    Manzotti, A.

    2018-02-01

    The primordial B-modes component of the cosmic microwave background (CMB) polarization is a promising experimental data set to probe the inflationary paradigm. B modes are indeed a direct consequence of the presence of gravitational waves in the early Universe. However, several secondary effects in the low-redshift universe will produce nonprimordial B modes. In particular, the gravitational interactions of CMB photons with large-scale structures will distort the primordial E modes, adding a lensing B-mode component to the primordial signal. Removing the lensing component ("delensing") will then be necessary to constrain the amplitude of the primordial gravitational waves. Here, we examine the role of current and future large-scale structure surveys in a multitracers approach to CMB delensing. We find that, in general, galaxy surveys should be split into tomographic bins, as this can increase the reduction of lensing B modes by ˜25 % in power in the most futuristic case. Ongoing or recently completed CMB experiments will particularly benefit from large-scale structure tracers that, once properly combined, will have a better performance than a CMB internal reconstruction. With the decrease of instrumental noise, the lensing B-modes power removed using CMB internal reconstruction alone will rapidly increase. Nevertheless, optical galaxy surveys will still play an important role even for fourth-generation CMB experiments. In particular, an LSST-like survey can a achieve a delensing performance comparable to a third-generation CMB experiment but with entirely different systematics. This redundancy will be essential to demonstrate the robustness against systematics of an eventual detection of primordial B modes.

  5. Joint analysis of galaxy-galaxy lensing and galaxy clustering: Methodology and forecasts for Dark Energy Survey

    International Nuclear Information System (INIS)

    Park, Y.; Krause, E.; Dodelson, S.; Jain, B.; Amara, A.

    2016-01-01

    Here, the joint analysis of galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth function of large-scale structure. Anticipating a near future application of this analysis to Dark Energy Survey (DES) measurements of galaxy positions and shapes, we develop a practical approach to modeling the assumptions and systematic effects affecting the joint analysis of small-scale galaxy-galaxy lensing and large-scale galaxy clustering. Introducing parameters that characterize the halo occupation distribution (HOD), photometric redshift uncertainties, and shear measurement errors, we study how external priors on different subsets of these parameters affect our growth constraints. Degeneracies within the HOD model, as well as between the HOD and the growth function, are identified as the dominant source of complication, with other systematic effects being subdominant. The impact of HOD parameters and their degeneracies necessitate the detailed joint modeling of the galaxy sample that we employ. We conclude that DES data will provide powerful constraints on the evolution of structure growth in the Universe, conservatively/optimistically constraining the growth function to 7.9%/4.8% with its first-year data that cover over 1000 square degrees, and to 3.9%/2.3% with its full five-year data that will survey 5000 square degrees, including both statistical and systematic uncertainties.

  6. 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.

  7. 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.

  8. The Splashback Feature around DES Galaxy Clusters: Galaxy Density and Weak Lensing Profiles

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chihway; et al.

    2017-10-18

    Splashback refers to the process of matter that is accreting onto a dark matter halo reaching its first orbital apocenter and turning around in its orbit. The cluster-centric radius at which this process occurs, r_sp, defines a halo boundary that is connected to the dynamics of the cluster, in contrast with other common halo boundary definitions such as R_200. A rapid decline in the matter density profile of the halo is expected near r_sp. We measure the galaxy number density and weak lensing mass profiles around RedMapper galaxy clusters in the first year Dark Energy Survey (DES) data. For a cluster sample with mean mass ~2.5 x 10^14 solar masses, we find strong evidence of a splashback-like steepening of the galaxy density profile and measure r_sp=1.16 +/- 0.08 Mpc/h, consistent with earlier SDSS measurements of More et al. (2016) and Baxter et al. (2017). Moreover, our weak lensing measurement demonstrates for the first time the existence of a splashback-like steepening of the matter profile of galaxy clusters. We measure r_sp=1.28 +/- 0.18 Mpc/h from the weak lensing data, in good agreement with our galaxy density measurements. Applying our analysis to different cluster and galaxy samples, we find that consistent with LambdaCDM simulations, r_sp scales with R_200m and does not evolve with redshift over the redshift range of 0.3--0.6. We also find that potential systematic effects associated with the RedMapper algorithm may impact the location of r_sp, in particular the choice of scale used to estimate cluster richness. We discuss progress needed to understand the systematic uncertainties and fully exploit forthcoming data from DES and future surveys, emphasizing the importance of more realistic mock catalogs and independent cluster samples.

  9. Bias to CMB lensing reconstruction from temperature anisotropies due to large-scale galaxy motions

    Science.gov (United States)

    Ferraro, Simone; Hill, J. Colin

    2018-01-01

    Gravitational lensing of the cosmic microwave background (CMB) is expected to be amongst the most powerful cosmological tools for ongoing and upcoming CMB experiments. In this work, we investigate a bias to CMB lensing reconstruction from temperature anisotropies due to the kinematic Sunyaev-Zel'dovich (kSZ) effect, that is, the Doppler shift of CMB photons induced by Compton scattering off moving electrons. The kSZ signal yields biases due to both its own intrinsic non-Gaussianity and its nonzero cross-correlation with the CMB lensing field (and other fields that trace the large-scale structure). This kSZ-induced bias affects both the CMB lensing autopower spectrum and its cross-correlation with low-redshift tracers. Furthermore, it cannot be removed by multifrequency foreground separation techniques because the kSZ effect preserves the blackbody spectrum of the CMB. While statistically negligible for current data sets, we show that it will be important for upcoming surveys, and failure to account for it can lead to large biases in constraints on neutrino masses or the properties of dark energy. For a stage 4 CMB experiment, the bias can be as large as ≈15 % or 12% in cross-correlation with LSST galaxy lensing convergence or galaxy overdensity maps, respectively, when the maximum temperature multipole used in the reconstruction is ℓmax=4000 , and about half of that when ℓmax=3000 . Similarly, we find that the CMB lensing autopower spectrum can be biased by up to several percent. These biases are many times larger than the expected statistical errors. We validate our analytical predictions with cosmological simulations and present the first complete estimate of secondary-induced CMB lensing biases. The predicted bias is sensitive to the small-scale gas distribution, which is affected by pressure and feedback mechanisms, thus making removal via "bias-hardened" estimators challenging. Reducing ℓmax can significantly mitigate the bias at the cost of a decrease

  10. Cosmic axion background propagation in galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Day, Francesca V., E-mail: francesca.day@physics.ox.ac.uk

    2016-02-10

    Many extensions of the Standard Model include axions or axion-like particles (ALPs). Here we study ALP to photon conversion in the magnetic field of the Milky Way and starburst galaxies. By modelling the effects of the coherent and random magnetic fields, the warm ionized medium and the warm neutral medium on the conversion process, we simulate maps of the conversion probability across the sky for a range of ALP energies. In particular, we consider a diffuse cosmic ALP background (CAB) analogous to the CMB, whose existence is suggested by string models of inflation. ALP–photon conversion of a CAB in the magnetic fields of galaxy clusters has been proposed as an explanation of the cluster soft X-ray excess. We therefore study the phenomenology and expected photon signal of CAB propagation in the Milky Way. We find that, for the CAB parameters required to explain the cluster soft X-ray excess, the photon flux from ALP–photon conversion in the Milky Way would be unobservably small. The ALP–photon conversion probability in galaxy clusters is 3 orders of magnitude higher than that in the Milky Way. Furthermore, the morphology of the unresolved cosmic X-ray background is incompatible with a significant component from ALP–photon conversion. We also consider ALP–photon conversion in starburst galaxies, which host much higher magnetic fields. By considering the clumpy structure of the galactic plasma, we find that conversion probabilities comparable to those in clusters may be possible in starburst galaxies.

  11. Planck 2013 results. XVIII. Gravitational lensing-infrared background correlation

    CERN Document Server

    Ade, P.A.R.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Bartlett, J.G.; Basak, S.; Battaner, E.; Benabed, K.; Benoit, A.; Benoit-Levy, A.; Bernard, J.P.; Bersanelli, M.; Bethermin, M.; Bielewicz, P.; Bobin, J.; Bock, J.J.; Bonaldi, A.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Boulanger, F.; Bridges, M.; Bucher, M.; Burigana, C.; Butler, R.C.; Cardoso, J.F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, L.Y.; Chiang, H.C.; Christensen, P.R.; Church, S.; Clements, D.L.; Colombi, S.; Colombo, L.P.L.; Couchot, F.; Coulais, A.; Crill, B.P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.M.; Desert, F.X.; Diego, J.M.; Dole, H.; Donzelli, S.; Dore, O.; Douspis, M.; Dupac, X.; Efstathiou, G.; Ensslin, T.A.; Eriksen, H.K.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; Giraud-Heraud, Y.; Gonzalez-Nuevo, J.; Gorski, K.M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J.E.; Hansen, F.K.; Hanson, D.; Harrison, D.; Henrot-Versille, S.; Hernandez-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huffenberger, K.M.; Jaffe, T.R.; Jaffe, A.H.; Jones, W.C.; Juvela, M.; Keihanen, E.; Keskitalo, R.; Kisner, T.S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lacasa, F.; Lagache, G.; Lahteenmaki, A.; Lamarre, J.M.; Lasenby, A.; Laureijs, R.J.; Lawrence, C.R.; Leonardi, R.; Leon-Tavares, J.; Lesgourgues, J.; Liguori, M.; Lilje, P.B.; Linden-Vornle, M.; Lopez-Caniego, M.; Lubin, P.M.; Macias-Perez, J.F.; Maffei, B.; Maino, D.; Mandolesi, N.; Maris, M.; Marshall, D.J.; Martin, P.G.; Martinez-Gonzalez, E.; Masi, S.; Matarrese, S.; Matthai, F.; Mazzotta, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschenes, M.A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Norgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Oxborrow, C.A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G.W.; Prezeau, G.; Prunet, S.; Puget, J.L.; Rachen, J.P.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rowan-Robinson, M.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Scott, D.; Seiffert, M.D.; Serra, P.; Shellard, E.P.S.; Spencer, L.D.; Starck, J.L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sureau, F.; Sutton, D.; Suur-Uski, A.S.; Sygnet, J.F.; Tauber, J.A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L.A.; Wandelt, B.D.; White, S.D.M.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-01-01

    The multi-frequency capability of the Planck satellite provides information both on the integrated history of star formation (via the cosmic infrared background, or CIB) and on the distribution of dark matter (via the lensing effect on the cosmic microwave background, or CMB). The conjunction of these two unique probes allows us to measure directly the connection between dark and luminous matter in the high redshift (1 1. We measure directly the SFR density with around 2 sigma significance for three redshift bins between z=1 and 7, thus opening a new window into the study of the formation of stars at early times.

  12. Galaxy-galaxy weak gravitational lensing in f(R) gravity

    Science.gov (United States)

    Li, Baojiu; Shirasaki, Masato

    2018-03-01

    We present an analysis of galaxy-galaxy weak gravitational lensing (GGL) in chameleon f(R) gravity - a leading candidate of non-standard gravity models. For the analysis, we have created mock galaxy catalogues based on dark matter haloes from two sets of numerical simulations, using a halo occupation distribution (HOD) prescription which allows a redshift dependence of galaxy number density. To make a fairer comparison between the f(R) and Λ cold dark matter (ΛCDM) models, their HOD parameters are tuned so that the galaxy two-point correlation functions in real space (and therefore the projected two-point correlation functions) match. While the f(R) model predicts an enhancement of the convergence power spectrum by up to ˜ 30 per cent compared to the standard ΛCDM model with the same parameters, the maximum enhancement of GGL is only half as large and less than 5 per cent on separations above ˜1-2 h-1 Mpc, because the latter is a cross-correlation of shear (or matter, which is more strongly affected by modified gravity) and galaxy (which is weakly affected given the good match between galaxy autocorrelations in the two models) fields. We also study the possibility of reconstructing the matter power spectrum by combination of GGL and galaxy clustering in f(R) gravity. We find that the galaxy-matter cross-correlation coefficient remains at unity down to ˜2-3 h-1 Mpc at relevant redshifts even in f(R) gravity, indicating joint analysis of GGL and galaxy clustering can be a powerful probe of matter density fluctuations in chameleon gravity. The scale dependence of the model differences in their predictions of GGL can potentially allows us to break the degeneracy between f(R) gravity and other cosmological parameters such as Ωm and σ8.

  13. The effects of assembly bias on the inference of matter clustering from galaxy-galaxy lensing and galaxy clustering

    Science.gov (United States)

    McEwen, Joseph E.; Weinberg, David H.

    2018-04-01

    The combination of galaxy-galaxy lensing (GGL) and galaxy clustering is a promising route to measuring the amplitude of matter clustering and testing modified gravity theories of cosmic acceleration. Halo occupation distribution (HOD) modeling can extend the approach down to nonlinear scales, but galaxy assembly bias could introduce systematic errors by causing the HOD to vary with large scale environment at fixed halo mass. We investigate this problem using the mock galaxy catalogs created by Hearin & Watson (2013, HW13), which exhibit significant assembly bias because galaxy luminosity is tied to halo peak circular velocity and galaxy colour is tied to halo formation time. The preferential placement of galaxies (especially red galaxies) in older halos affects the cutoff of the mean occupation function for central galaxies, with halos in overdense regions more likely to host galaxies. The effect of assembly bias on the satellite galaxy HOD is minimal. We introduce an extended, environment dependent HOD (EDHOD) prescription to describe these results and fit galaxy correlation measurements. Crucially, we find that the galaxy-matter cross-correlation coefficient, rgm(r) ≡ ξgm(r) . [ξmm(r)ξgg(r)]-1/2, is insensitive to assembly bias on scales r ≳ 1 h^{-1} Mpc, even though ξgm(r) and ξgg(r) are both affected individually. We can therefore recover the correct ξmm(r) from the HW13 galaxy-galaxy and galaxy-matter correlations using either a standard HOD or EDHOD fitting method. For Mr ≤ -19 or Mr ≤ -20 samples the recovery of ξmm(r) is accurate to 2% or better. For a sample of red Mr ≤ -20 galaxies we achieve 2% recovery at r ≳ 2 h^{-1} Mpc with EDHOD modeling but lower accuracy at smaller scales or with a standard HOD fit. Most of our mock galaxy samples are consistent with rgm = 1 down to r = 1h-1Mpc, to within the uncertainties set by our finite simulation volume.

  14. The detection of the imprint of filaments on cosmic microwave background lensing

    Science.gov (United States)

    He, Siyu; Alam, Shadab; Ferraro, Simone; Chen, Yen-Chi; Ho, Shirley

    2018-04-01

    Galaxy redshift surveys, such as the 2-Degree-Field Survey (2dF)1, Sloan Digital Sky Survey (SDSS)2, 6-Degree-Field Survey (6dF)3, Galaxy And Mass Assembly survey (GAMA)4 and VIMOS Public Extragalactic Redshift Survey (VIPERS)5, have shown that the spatial distribution of matter forms a rich web, known as the cosmic web6. Most galaxy survey analyses measure the amplitude of galaxy clustering as a function of scale, ignoring information beyond a small number of summary statistics. Because the matter density field becomes highly non-Gaussian as structure evolves under gravity, we expect other statistical descriptions of the field to provide us with additional information. One way to study the non-Gaussianity is to study filaments, which evolve non-linearly from the initial density fluctuations produced in the primordial Universe. In our study, we report the detection of lensing of the cosmic microwave background (CMB) by filaments, and we apply a null test to confirm our detection. Furthermore, we propose a phenomenological model to interpret the detected signal, and we measure how filaments trace the matter distribution on large scales through filament bias, which we measure to be around 1.5. Our study provides new scope to understand the environmental dependence of galaxy formation. In the future, the joint analysis of lensing and Sunyaev-Zel'dovich observations might reveal the properties of `missing baryons', the vast majority of the gas that resides in the intergalactic medium, which has so far evaded most observations.

  15. Dusty starburst galaxies in the early Universe as revealed by gravitational lensing.

    Science.gov (United States)

    Vieira, J D; Marrone, D P; Chapman, S C; De Breuck, C; Hezaveh, Y D; Weiβ, A; Aguirre, J E; Aird, K A; Aravena, M; Ashby, M L N; Bayliss, M; Benson, B A; Biggs, A D; Bleem, L E; Bock, J J; Bothwell, M; Bradford, C M; Brodwin, M; Carlstrom, J E; Chang, C L; Crawford, T M; Crites, A T; de Haan, T; Dobbs, M A; Fomalont, E B; Fassnacht, C D; George, E M; Gladders, M D; Gonzalez, A H; Greve, T R; Gullberg, B; Halverson, N W; High, F W; Holder, G P; Holzapfel, W L; Hoover, S; Hrubes, J D; Hunter, T R; Keisler, R; Lee, A T; Leitch, E M; Lueker, M; Luong-Van, D; Malkan, M; McIntyre, V; McMahon, J J; Mehl, J; Menten, K M; Meyer, S S; Mocanu, L M; Murphy, E J; Natoli, T; Padin, S; Plagge, T; Reichardt, C L; Rest, A; Ruel, J; Ruhl, J E; Sharon, K; Schaffer, K K; Shaw, L; Shirokoff, E; Spilker, J S; Stalder, B; Staniszewski, Z; Stark, A A; Story, K; Vanderlinde, K; Welikala, N; Williamson, R

    2013-03-21

    In the past decade, our understanding of galaxy evolution has been revolutionized by the discovery that luminous, dusty starburst galaxies were 1,000 times more abundant in the early Universe than at present. It has, however, been difficult to measure the complete redshift distribution of these objects, especially at the highest redshifts (z > 4). Here we report a redshift survey at a wavelength of three millimetres, targeting carbon monoxide line emission from the star-forming molecular gas in the direction of extraordinarily bright millimetre-wave-selected sources. High-resolution imaging demonstrates that these sources are strongly gravitationally lensed by foreground galaxies. We detect spectral lines in 23 out of 26 sources and multiple lines in 12 of those 23 sources, from which we obtain robust, unambiguous redshifts. At least 10 of the sources are found to lie at z > 4, indicating that the fraction of dusty starburst galaxies at high redshifts is greater than previously thought. Models of lens geometries in the sample indicate that the background objects are ultra-luminous infrared galaxies, powered by extreme bursts of star formation.

  16. Cosmic axion background propagation in galaxies

    Directory of Open Access Journals (Sweden)

    Francesca V. Day

    2016-02-01

    Full Text Available Many extensions of the Standard Model include axions or axion-like particles (ALPs. Here we study ALP to photon conversion in the magnetic field of the Milky Way and starburst galaxies. By modelling the effects of the coherent and random magnetic fields, the warm ionized medium and the warm neutral medium on the conversion process, we simulate maps of the conversion probability across the sky for a range of ALP energies. In particular, we consider a diffuse cosmic ALP background (CAB analogous to the CMB, whose existence is suggested by string models of inflation. ALP–photon conversion of a CAB in the magnetic fields of galaxy clusters has been proposed as an explanation of the cluster soft X-ray excess. We therefore study the phenomenology and expected photon signal of CAB propagation in the Milky Way. We find that, for the CAB parameters required to explain the cluster soft X-ray excess, the photon flux from ALP–photon conversion in the Milky Way would be unobservably small. The ALP–photon conversion probability in galaxy clusters is 3 orders of magnitude higher than that in the Milky Way. Furthermore, the morphology of the unresolved cosmic X-ray background is incompatible with a significant component from ALP–photon conversion. We also consider ALP–photon conversion in starburst galaxies, which host much higher magnetic fields. By considering the clumpy structure of the galactic plasma, we find that conversion probabilities comparable to those in clusters may be possible in starburst galaxies.

  17. A CFH12k lensing survey of X-ray luminous galaxy clusters - II. Weak lensing analysis and global correlations

    NARCIS (Netherlands)

    Bardeau, S.; Soucail, G.; Kneib, J.-P.; Czoske, O.; Ebeling, H.; Hudelot, P.; Smail, I.; Smith, G. P.

    Aims. We present a wide-field multi-color survey of a homogeneous sample of eleven clusters of galaxies for which we measure total masses and mass distributions from weak lensing. This sample, spanning a small range in both X-ray luminosity and redshift, is ideally suited to determining the

  18. 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

  19. SOURCE-PLANE RECONSTRUCTION OF THE BRIGHT LENSED GALAXY RCSGA 032727-132609

    Energy Technology Data Exchange (ETDEWEB)

    Sharon, Keren; Gladders, Michael D.; Wuyts, Eva; Bayliss, Matthew B. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Rigby, Jane R. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Koester, Benjamin P. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Barrientos, L. Felipe, E-mail: kerens@kicp.uchicago.edu [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Avda. Vicuna Mackenna 4860, Casilla 306, Santiago 22 (Chile)

    2012-02-20

    We present new Hubble Space Telescope/Wide Field Camera 3 imaging data of RCSGA 032727-132609, a bright lensed galaxy at z = 1.7 that is magnified and stretched by the lensing cluster RCS2 032727-132623. Using this new high-resolution imaging, we modify our previous lens model (which was based on ground-based data) to fully understand the lensing geometry, and use it to reconstruct the lensed galaxy in the source plane. This giant arc represents a unique opportunity to peer into 100 pc scale structures in a high-redshift galaxy. This new source reconstruction will be crucial for a future analysis of the spatially resolved rest-UV and rest-optical spectra of the brightest parts of the arc.

  20. Bayesian galaxy shape measurement for weak lensing surveys - III. Application to the Canada-France-Hawaii Telescope Lensing Survey

    Science.gov (United States)

    Miller, L.; Heymans, C.; Kitching, T. D.; van Waerbeke, L.; Erben, T.; Hildebrandt, H.; Hoekstra, H.; Mellier, Y.; Rowe, B. T. P.; Coupon, J.; Dietrich, J. P.; Fu, L.; Harnois-Déraps, J.; Hudson, M. J.; Kilbinger, M.; Kuijken, K.; Schrabback, T.; Semboloni, E.; Vafaei, S.; Velander, M.

    2013-03-01

    A likelihood-based method for measuring weak gravitational lensing shear in deep galaxy surveys is described and applied to the Canada-France-Hawaii Telescope (CFHT) Lensing Survey (CFHTLenS). CFHTLenS comprises 154 deg2 of multi-colour optical data from the CFHT Legacy Survey, with lensing measurements being made in the i' band to a depth i'AB noise ratio νSN ≳ 10. The method is based on the lensfit algorithm described in earlier papers, but here we describe a full analysis pipeline that takes into account the properties of real surveys. The method creates pixel-based models of the varying point spread function (PSF) in individual image exposures. It fits PSF-convolved two-component (disc plus bulge) models to measure the ellipticity of each galaxy, with Bayesian marginalization over model nuisance parameters of galaxy position, size, brightness and bulge fraction. The method allows optimal joint measurement of multiple, dithered image exposures, taking into account imaging distortion and the alignment of the multiple measurements. We discuss the effects of noise bias on the likelihood distribution of galaxy ellipticity. Two sets of image simulations that mirror the observed properties of CFHTLenS have been created to establish the method's accuracy and to derive an empirical correction for the effects of noise bias.

  1. MISSING LENSED IMAGES AND THE GALAXY DISK MASS IN CXOCY J220132.8-320144

    International Nuclear Information System (INIS)

    Chen, Jacqueline; Lee, Samuel K.; Schechter, Paul L.; Castander, Francisco-Javier; Maza, José

    2013-01-01

    The CXOCY J220132.8-320144 system consists of an edge-on spiral galaxy lensing a background quasar into two bright images. Previous efforts to constrain the mass distribution in the galaxy have suggested that at least one additional image must be present. These extra images may be hidden behind the disk which features a prominent dust lane. We present and analyze Hubble Space Telescope observations of the system. We do not detect any extra images, but the observations further narrow the observable parameters of the lens system. We explore a range of models to describe the mass distribution in the system and find that a variety of acceptable model fits exist. All plausible models require 2 mag of dust extinction in order to obscure extra images from detection, and some models may require an offset between the center of the galaxy and the center of the dark matter halo of 1 kpc. Currently unobserved images will be detectable by future James Webb Space Telescope observations and will provide strict constraints on the fraction of mass in the disk.

  2. Dark Energy Survey Year 1 Results: Cosmological Constraints from Galaxy Clustering and Weak Lensing

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, T.M.C.; et al.

    2017-08-04

    We present cosmological results from a combined analysis of galaxy clustering and weak gravitational lensing, using 1321 deg$^2$ of $griz$ imaging data from the first year of the Dark Energy Survey (DES Y1). We combine three two-point functions: (i) the cosmic shear correlation function of 26 million source galaxies in four redshift bins, (ii) the galaxy angular autocorrelation function of 650,000 luminous red galaxies in five redshift bins, and (iii) the galaxy-shear cross-correlation of luminous red galaxy positions and source galaxy shears. To demonstrate the robustness of these results, we use independent pairs of galaxy shape, photometric redshift estimation and validation, and likelihood analysis pipelines. To prevent confirmation bias, the bulk of the analysis was carried out while blind to the true results; we describe an extensive suite of systematics checks performed and passed during this blinded phase. The data are modeled in flat $\\Lambda$CDM and $w$CDM cosmologies, marginalizing over 20 nuisance parameters, varying 6 (for $\\Lambda$CDM) or 7 (for $w$CDM) cosmological parameters including the neutrino mass density and including the 457 $\\times$ 457 element analytic covariance matrix. We find consistent cosmological results from these three two-point functions, and from their combination obtain $S_8 \\equiv \\sigma_8 (\\Omega_m/0.3)^{0.5} = 0.783^{+0.021}_{-0.025}$ and $\\Omega_m = 0.264^{+0.032}_{-0.019}$ for $\\Lambda$CDM for $w$CDM, we find $S_8 = 0.794^{+0.029}_{-0.027}$, $\\Omega_m = 0.279^{+0.043}_{-0.022}$, and $w=-0.80^{+0.20}_{-0.22}$ at 68% CL. The precision of these DES Y1 results rivals that from the Planck cosmic microwave background measurements, allowing a comparison of structure in the very early and late Universe on equal terms. Although the DES Y1 best-fit values for $S_8$ and $\\Omega_m$ are lower than the central values from Planck ...

  3. A KiDS weak lensing analysis of assembly bias in GAMA galaxy groups

    Science.gov (United States)

    Dvornik, Andrej; Cacciato, Marcello; Kuijken, Konrad; Viola, Massimo; Hoekstra, Henk; Nakajima, Reiko; van Uitert, Edo; Brouwer, Margot; Choi, Ami; Erben, Thomas; Fenech Conti, Ian; Farrow, Daniel J.; Herbonnet, Ricardo; Heymans, Catherine; Hildebrandt, Hendrik; Hopkins, Andrew M.; McFarland, John; Norberg, Peder; Schneider, Peter; Sifón, Cristóbal; Valentijn, Edwin; Wang, Lingyu

    2017-07-01

    We investigate possible signatures of halo assembly bias for spectroscopically selected galaxy groups from the Galaxy And Mass Assembly (GAMA) survey using weak lensing measurements from the spatially overlapping regions of the deeper, high-imaging-quality photometric Kilo-Degree Survey. We use GAMA groups with an apparent richness larger than 4 to identify samples with comparable mean host halo masses but with a different radial distribution of satellite galaxies, which is a proxy for the formation time of the haloes. We measure the weak lensing signal for groups with a steeper than average and with a shallower than average satellite distribution and find no sign of halo assembly bias, with the bias ratio of 0.85^{+0.37}_{-0.25}, which is consistent with the Λ cold dark matter prediction. Our galaxy groups have typical masses of 1013 M⊙ h-1, naturally complementing previous studies of halo assembly bias on galaxy cluster scales.

  4. The Lenses Structure and Dynamics Survey: luminous and dark matter in high redshift early-type galaxies

    NARCIS (Netherlands)

    Treu, T.; Koopmans, L.

    2003-01-01

    I will present the latest results from the Lenses Structure and Dynamics (LSD) Survey. Using ESI on the Keck Telescope, we have measured spatially resolved stellar kinematics for a sample of 11 early-type galaxies (E/S0s) in the range z=0.1-1, selected as gravitational lenses. By combining lensing

  5. CLASH: Extending galaxy strong lensing to small physical scales with distant sources highly magnified by galaxy cluster members

    International Nuclear Information System (INIS)

    Grillo, C.; Christensen, L.; Gobat, R.; Presotto, V.; Balestra, I.; Nonino, M.; Biviano, A.; Mercurio, A.; Rosati, P.; Vanzella, E.; Graves, G.; Lemze, D.; Ford, H.; Bartelmann, M.; Benitez, N.; Bouwens, R.; Bradley, L.; Coe, D.; Broadhurst, T.; Donahue, M.

    2014-01-01

    We present a complex strong lensing system in which a double source is imaged five times by two early-type galaxies. We take advantage in this target of the extraordinary multi-band photometric data set obtained as part of the Cluster Lensing And Supernova survey with Hubble (CLASH) program, complemented by the spectroscopic measurements of the VLT/VIMOS and FORS2 follow-up campaign. We use a photometric redshift value of 3.7 for the source and confirm spectroscopically the membership of the two lenses to the galaxy cluster MACS J1206.2–0847 at redshift 0.44. We exploit the excellent angular resolution of the HST/ACS images to model the two lenses in terms of singular isothermal sphere profiles and derive robust effective velocity dispersion values of 97 ± 3 and 240 ± 6 km s –1 . Interestingly, the total mass distribution of the cluster is also well characterized by using only the local information contained in this lensing system, which is located at a projected distance of more than 300 kpc from the cluster luminosity center. According to our best-fitting lensing and composite stellar population models, the source is magnified by a total factor of 50 and has a luminous mass of approximately (1.0 ± 0.5) × 10 9 M ☉ (assuming a Salpeter stellar initial mass function). By combining the total and luminous mass estimates of the two lenses, we measure luminous over total mass fractions projected within the effective radii of 0.51 ± 0.21 and 0.80 ± 0.32. Remarkably, with these lenses we can extend the analysis of the mass properties of lens early-type galaxies by factors that are approximately two and three times smaller than previously done with regard to, respectively, velocity dispersion and luminous mass. The comparison of the total and luminous quantities of our lenses with those of astrophysical objects with different physical scales, like massive early-type galaxies and dwarf spheroidals, reveals the potential of studies of this kind for improving our

  6. Lensing convergence in galaxy clustering in ΛCDM and beyond

    Science.gov (United States)

    Villa, Eleonora; Di Dio, Enea; Lepori, Francesca

    2018-04-01

    We study the impact of neglecting lensing magnification in galaxy clustering analyses for future galaxy surveys, considering the ΛCDM model and two extensions: massive neutrinos and modifications of General Relativity. Our study focuses on the biases on the constraints and on the estimation of the cosmological parameters. We perform a comprehensive investigation of these two effects for the upcoming photometric and spectroscopic galaxy surveys Euclid and SKA for different redshift binning configurations. We also provide a fitting formula for the magnification bias of SKA. Our results show that the information present in the lensing contribution does improve the constraints on the modified gravity parameters whereas the lensing constraining power is negligible for the ΛCDM parameters. For photometric surveys the estimation is biased for all the parameters if lensing is not taken into account. This effect is particularly significant for the modified gravity parameters. Conversely for spectroscopic surveys the bias is below one sigma for all the parameters. Our findings show the importance of including lensing in galaxy clustering analyses for testing General Relativity and to constrain the parameters which describe its modifications.

  7. Near-IR search for lensed supernovae behind galaxy clusters. II. First detection and future prospects

    OpenAIRE

    Goobar, A.; Paech, K.; Stanishev, V.; Amanullah, R.; Dahlén, T.; Jönsson, J.; Kneib, J. P.; Lidman, C.; Limousin, M.; Mörtsell, E.; Nobili, S.; Richard, J.; Riehm, T.; von Strauss, M.

    2009-01-01

    Aims. Powerful gravitational telescopes in the form of massive galaxy clusters can be used to enhance the light collecting power over a limited field of view by about an order of magnitude in flux. This effect is exploited here to increase the depth of a survey for lensed supernovae at near-IR wavelengths. Methods. We present a pilot supernova search programme conducted with the ISAAC camera at VLT. Lensed galaxies behind the massive clusters A1689, A1835, and AC114 were observed for a tot...

  8. The detection of a population of submillimeter-bright, strongly lensed galaxies.

    Science.gov (United States)

    Negrello, Mattia; Hopwood, R; De Zotti, G; Cooray, A; Verma, A; Bock, J; Frayer, D T; Gurwell, M A; Omont, A; Neri, R; Dannerbauer, H; Leeuw, L L; Barton, E; Cooke, J; Kim, S; da Cunha, E; Rodighiero, G; Cox, P; Bonfield, D G; Jarvis, M J; Serjeant, S; Ivison, R J; Dye, S; Aretxaga, I; Hughes, D H; Ibar, E; Bertoldi, F; Valtchanov, I; Eales, S; Dunne, L; Driver, S P; Auld, R; Buttiglione, S; Cava, A; Grady, C A; Clements, D L; Dariush, A; Fritz, J; Hill, D; Hornbeck, J B; Kelvin, L; Lagache, G; Lopez-Caniego, M; Gonzalez-Nuevo, J; Maddox, S; Pascale, E; Pohlen, M; Rigby, E E; Robotham, A; Simpson, C; Smith, D J B; Temi, P; Thompson, M A; Woodgate, B E; York, D G; Aguirre, J E; Beelen, A; Blain, A; Baker, A J; Birkinshaw, M; Blundell, R; Bradford, C M; Burgarella, D; Danese, L; Dunlop, J S; Fleuren, S; Glenn, J; Harris, A I; Kamenetzky, J; Lupu, R E; Maddalena, R J; Madore, B F; Maloney, P R; Matsuhara, H; Michaowski, M J; Murphy, E J; Naylor, B J; Nguyen, H; Popescu, C; Rawlings, S; Rigopoulou, D; Scott, D; Scott, K S; Seibert, M; Smail, I; Tuffs, R J; Vieira, J D; van der Werf, P P; Zmuidzinas, J

    2010-11-05

    Gravitational lensing is a powerful astrophysical and cosmological probe and is particularly valuable at submillimeter wavelengths for the study of the statistical and individual properties of dusty star-forming galaxies. However, the identification of gravitational lenses is often time-intensive, involving the sifting of large volumes of imaging or spectroscopic data to find few candidates. We used early data from the Herschel Astrophysical Terahertz Large Area Survey to demonstrate that wide-area submillimeter surveys can simply and easily detect strong gravitational lensing events, with close to 100% efficiency.

  9. Stellar Populations of Highly Magnified Lensed Galaxies Young Starburst at Z to Approximately 2

    Science.gov (United States)

    Wuyts, Eva; Rigby, Jane R.; Gladders, Michael D.; Gilbank, David G.; Sharon, Keren; Gralla, Megan B.; Bayliss, Matthew B.

    2011-01-01

    We present a comprehensive analysis of the rest-frame UV to near-IR spectral energy distributions and rest-frame optical spectra of four of the brightest gravitationally lensed galaxies in the literature: RCSGA 032727-132609 at z = 170, MS1512-cB58 at z = 2.73, SGAS J152745.1+065219 at z = 2.76 and SGAS J12265L3+215220 at z = 2.92. This includes new Spitzer imaging for RCSGA0327 as well as new spectra, near-IR imaging and Spitzer imaging for SGAS1527 and SGAS1226. Lensing magnifications of 3-4 magnitudes allow a detailed study of the stellar populations and physical conditions. We compare star formation rates as measured from the SED fit, the Ha and [O II] .(lambda)3727 emission lines, and the UV+IR bolometric luminosity where 24micron photometry is available. The SFR estimate from the SED fit is consistently higher than the other indicators, which suggests that the Calzetti dust extinction law used in the SED fitting is too flat for young star-forming galaxies at z approx. 2. Our analysis finds similar stellar population parameters for all four lensed galaxies: stellar masses 3 - 7 x 10(exp 9) Stellar mass, young ages approx. 100 Myr, little dust content E(B - V)=0.10-0.25, and star formation rates around 20- 100 Stellar mass/y. Compared to typical values for the galaxy population at z approx. 2, this suggests we are looking at newly formed, starbursting systems that have only recently started the build-up of stellar mass. These results constitute the first detailed, uniform analysis of a sample of the growing number of strongly lensed galaxies known at z approx. 2. Subject headings: galaxies: high-redshift, strong gravitational lensing, infrared: galaxies

  10. Galaxy bias from the Dark Energy Survey Science Verification data: combining galaxy density maps and weak lensing maps

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.; Pujol, A.; Gaztañaga, E.; Amara, A.; Réfrégier, A.; Bacon, D.; Becker, M. R.; Bonnett, C.; Carretero, J.; Castander, F. J.; Crocce, M.; Fosalba, P.; Giannantonio, T.; Hartley, W.; Jarvis, M.; Kacprzak, T.; Ross, A. J.; Sheldon, E.; Troxel, M. A.; Vikram, V.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Kind, M. Carrasco; Cunha, C. E.; D' Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Estrada, J.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; Jain, B.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Ogando, R.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.

    2016-04-15

    We measure the redshift evolution of galaxy bias from a magnitude-limited galaxy sample by combining the galaxy density maps and weak lensing shear maps for a $\\sim$116 deg$^{2}$ area of the Dark Energy Survey (DES) Science Verification data. This method was first developed in Amara et al. (2012) and later re-examined in a companion paper (Pujol et al., in prep) with rigorous simulation tests and analytical treatment of tomographic measurements. In this work we apply this method to the DES SV data and measure the galaxy bias for a magnitude-limited galaxy sample. We find the galaxy bias and 1$\\sigma$ error bars in 4 photometric redshift bins to be 1.33$\\pm$0.18 (z=0.2-0.4), 1.19$\\pm$0.23 (z=0.4-0.6), 0.99$\\pm$0.36 ( z=0.6-0.8), and 1.66$\\pm$0.56 (z=0.8-1.0). These measurements are consistent at the 1-2$\\sigma$ level with mea- surements on the same dataset using galaxy clustering and cross-correlation of galaxies with CMB lensing. In addition, our method provides the only $\\sigma_8$-independent constraint among the three. We forward-model the main observational effects using mock galaxy catalogs by including shape noise, photo-z errors and masking effects. We show that our bias measurement from the data is consistent with that expected from simulations. With the forthcoming full DES data set, we expect this method to provide additional constraints on the galaxy bias measurement from more traditional methods. Furthermore, in the process of our measurement, we build up a 3D mass map that allows further exploration of the dark matter distribution and its relation to galaxy evolution.

  11. Investigating the internal structure of galaxies and clusters through strong gravitational lensing

    Science.gov (United States)

    Jigish Gandhi, Pratik; Grillo, Claudio; Bonamigo, Mario

    2018-01-01

    Gravitational lensing studies have radically improved our understanding of the internal structure of galaxies and cluster-scale systems. In particular, the combination of strong lensing and stellar dynamics or stellar population synthesis models have made it possible to characterize numerous fundamental properties of the galaxies as well as dark matter halos and subhalos with unprecedented robustness and accuracy. Here we demonstrate the usefulness and accuracy of strong lensing as a probe for characterising the properties of cluster members as well as dark matter halos, to show that such characterisation carried out via lensing analyses alone is as viable as those carried out through a combination of spectroscopy and lensing analyses.Our study uses focuses on the early-type galaxy cluster MACS J1149.5+2223 at redshift 0.54 in the Hubble Frontier Fields (HFF) program, where the first magnified and spatially resolved multiple images of supernova (SN) “Refsdal” and its late-type host galaxy at redshift 1.489 were detected. The Refsdal system is unique in being the first ever multiply-imaged supernova, with it’s first four images appearing in an Einstein Cross configuration around one of the cluster members in 2015. In our lensing analyses we use HST data of the multiply-imaged SN Refsdal to constrain the dynamical masses, velocity dispersions, and virial radii of individual galaxies and dark matter halos in the MACS J1149.5+2223 cluster. For our lensing models we select a sample of 300 cluster members within approximately 500 kpc from the BCG, and a set of reliable multiple images associated with 18 distinct knots in the SN host spiral galaxy, as well as multiple images of the supernova itself. Our results provide accurate measurements of the masses, velocity dispersions, and radii of the cluster’s dark matter halo as well as three chosen members galaxies, in strong agreement with those obtained by Grillo et al 2015, demonstrating the usefulness of strong

  12. Galaxy-galaxy lensing constraints on the relation between baryons and dark matter in galaxies in the Red Sequence Cluster Survey 2

    OpenAIRE

    van Uitert, Edo; Hoekstra, Henk; Velander, Malin; Gilbank, David G.; Gladders, Michael D.; Yee, H. K. C.

    2011-01-01

    We present the results of a study of weak gravitational lensing by galaxies using imaging data that were obtained as part of the second Red Sequence Cluster Survey (RCS2). In order to compare to the baryonic properties of the lenses we focus here on the ~300 square degrees that overlap with the DR7 of the SDSS. The depth and image quality of the RCS2 enables us to significantly improve upon earlier work for luminous galaxies at z>=0.3. Comparison with dynamical masses from the SDSS shows a go...

  13. Weak Lensing Calibrated M-T Scaling Relation of Galaxy Groups in the COSMOS Field

    NARCIS (Netherlands)

    Kettula, K.; Finoguenov, A.; Massey, R.; Rhodes, J.; Hoekstra, H.; Taylor, J.; Spinelli, P.; Tanaka, M.; Ilbert, O.; Capak, P.; McCracken, H.; Koekemoer, A.

    2013-01-01

    The scaling between X-ray observables and mass for galaxy clusters and groups is instrumental for cluster-based cosmology and an important probe for the thermodynamics of the intracluster gas. We calibrate a scaling relation between the weak lensing mass and X-ray spectroscopic temperature for 10

  14. CLASS B 1359 + 154: Modelling Lensing by a Group of Galaxies

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    systems: CLASS B1359 + 154—galaxy groups—dark matter. 1. Introduction. A find of the Cosmic Lens All-Sky Survey (CLASS; Myers et al. 1995), the radio lensed system B1359 + 154 was at first identified as a quadruply-imaged ('quad') system (Myers et al. 1999), although six compact radio features had been detected in.

  15. A KiDS weak lensing analysis of assembly bias in GAMA galaxy groups

    NARCIS (Netherlands)

    Dvornik, Andrej; Cacciato, Marcello; Kuijken, Konrad; Viola, Massimo; Hoekstra, Henk; Nakajima, Reiko; van Uitert, Edo; Brouwer, Margot; Choi, Ami; Erben, Thomas; Fenech Conti, Ian; Farrow, Daniel J.; Herbonnet, Ricardo; Heymans, Catherine; Hildebrandt, Hendrik; Hopkins, Andrew. M.; McFarland, John; Norberg, Peder; Schneider, Peter; Sifón, Cristóbal; Valentijn, Edwin; Wang, Lingyu

    2017-01-01

    We investigate possible signatures of halo assembly bias for spectroscopically selected galaxy groups from the GAMA survey using weak lensing measurements from the spatially overlapping regions of the deeper, high-imaging-quality photometric KiDS survey. We use GAMA groups with an apparent richness

  16. High-z early-type galaxies: mass and light from gravitational lensing and stellar kinematics

    Science.gov (United States)

    Treu, T.; Koopmans, L.

    2002-12-01

    I will report on new results from the Lenses Structure and Dynamics Survey. We have measured spatially resolved velocity dispersion profiles of a sample of 11 distant (up to z=1) early-type galaxies that are gravitational lenses. By combining lensing and dynamical analysis we firmly constrain the dark matter density profile, the controversial inner slope of the dark matter halo, and the total mass distribution, and we give some constraints on the stellar orbits. In particular, I will discuss the implications of this measurement on the epoch and mechanism of formation of early-type galaxies, on the universal dark matter halos predicted by cold dark matter scenarios, and on the measurement of the Hubble Constant from gravitational time-delay observations. Financial support for proposals HST-AR 9222 and HST-AR-09527 provided by NASA through a grant from STScI, which is operated by AURA under NASA contract NAS5-26555 is gratfully acknowledged.

  17. 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.

  18. A Spectroscopic Survey of Lensed Dwarf Galaxies at 1

    Science.gov (United States)

    Alavi, Anahita; Siana, Brian; gburek, Timothy; Richard, Johan; Teplitz, Harry; Rafelski, Marc; Stark, Daniel P.; Anahita Alavi

    2018-01-01

    High-redshift dwarf galaxies (Mtalk, I will present their nebular dust attenuation measurements using the ratio of Balmer lines (i.e., Balmer decrement) and compare with their stellar dust attenuation (i.e., from UV spectral slopes). I will also show that these faint galaxies follow a steep dust extinction curve (i.e., SMC like).

  19. SUNYAEV-ZEL'DOVICH EFFECT OBSERVATIONS OF STRONG LENSING GALAXY CLUSTERS: PROBING THE OVERCONCENTRATION PROBLEM

    International Nuclear Information System (INIS)

    Gralla, Megan B.; Gladders, Michael D.; Marrone, Daniel P.; Bayliss, Matthew; Carlstrom, John E.; Greer, Christopher; Hennessy, Ryan; Koester, Benjamin; Leitch, Erik; Sharon, Keren; Barrientos, L. Felipe; Bonamente, Massimiliano; Bulbul, Esra; Hasler, Nicole; Culverhouse, Thomas; Hawkins, David; Lamb, James; Gilbank, David G.; Joy, Marshall; Miller, Amber

    2011-01-01

    We have measured the Sunyaev-Zel'dovich (SZ) effect for a sample of 10 strong lensing selected galaxy clusters using the Sunyaev-Zel'dovich Array (SZA). The SZA is sensitive to structures on spatial scales of a few arcminutes, while the strong lensing mass modeling constrains the mass at small scales (typically <30''). Combining the two provides information about the projected concentrations of the strong lensing clusters. The Einstein radii we measure are twice as large as expected given the masses inferred from SZ scaling relations. A Monte Carlo simulation indicates that a sample randomly drawn from the expected distribution would have a larger median Einstein radius than the observed clusters about 3% of the time. The implied overconcentration has been noted in previous studies and persists for this sample, even when we take into account that we are selecting large Einstein radius systems, suggesting that the theoretical models still do not fully describe the observed properties of strong lensing clusters.

  20. 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.

  1. Arcs from gravitational lensing

    Science.gov (United States)

    Grossman, Scott A.; Narayan, Ramesh

    1988-01-01

    The proposal made by Paczynski (1987) that the arcs of blue light found recently in two cluster cores are gravitationally lensed elongated images of background galaxies is investigated. It is shown that lenses that are circularly symmetric in projection produce pairs of arcs, in conflict with the observations. However, more realistic asymmetric lenses produce single arcs, which can become as elongated as the observed ones whenever the background galaxy is located on or close to a cusp caustic. Detailed computer simulations of lensing by clusters using a reasonable model of the mass distribution are presented. Elongated and curved lensed images longer than 10 arcsec occur in 12 percent of the simulated clusters. It is concluded that the lensing hypothesis must be taken seriously.

  2. The Physical Conditions of a Lensed Star-Forming Galaxy at Z=1.7

    Science.gov (United States)

    Rigby, Jane; Wuyts, E.; Gladders, M.; Sharon, K.; Becker, G.

    2011-01-01

    We report rest-frame optical Keck/NIRSPEC spectroscopy of the brightest lensed galaxy yet discovered, RCSGA 032727-132609 at z=1.7037. From precise measurements of the nebular lines, we infer a number of physical properties: redshift ' extinction, star formation rate ' ionization parameter, electron density, electron temperature, oxygen abundance, and N/O, Ne/O, and Ar/O abundance ratios, The limit on [O III] 4363 A tightly constrains the oxygen abundance via the "direct" or Te method, for the first time in an average-metallicity galaxy at z approx.2. We compare this result to several standard "bright-line" O abundance diagnostics, thereby testing these empirically-calibrated diagnostics in situ. Finally, we explore the positions of lensed and unlensed galaxies in standard diagnostic diagrams, to explore the diversity of ionization conditions and mass-metallicity ratios at z=2.

  3. Physical Conditions of a Lensed Star-Forming Galaxy at Z=1.7

    Science.gov (United States)

    Rigby, Jane; Wuyts, E.; Gladders, M.; Sharon, K.; Becker, G. D.

    2010-01-01

    We report rest-frame optical Keck/NIRSPEC spectroscopy of the brightest lensed galaxy yet discovered, RCSGA 032727-132609 at z=1.7037. From precise measurements of the nebular lines, we infer a number of physical properties: redshift, extinction, star formation rate, ionization parameter, electron density, electron temperature, oxygen abundance, and N/O, Ne/O, and Ar/O abundance ratios. The limit on [O III] 4363 A tightly constrains the oxygen abundance via the "direct" or Tc method, for the first time in all metallicity galaxy at z approx.2. We compare this result to several standard "bright-line" O abundance diagnostics, thereby testing these empirically calibrated diagnostics in situ. Finally, we explore the positions of lensed and unlensed galaxies in standard diagnostic diagrams, and explore the diversity of ionization conditions and mass-metallicity ratios at z=2.

  4. The weak lensing analysis of the CFHTLS and NGVS RedGOLD galaxy clusters

    Science.gov (United States)

    Parroni, C.; Mei, S.; Erben, T.; Van Waerbeke, L.; Raichoor, A.; Ford, J.; Licitra, R.; Meneghetti, M.; Hildebrandt, H.; Miller, L.; Côté, P.; Covone, G.; Cuillandre, J.-C.; Duc, P.-A.; Ferrarese, L.; Gwyn, S. D. J.; Puzia, T. H.

    2017-12-01

    An accurate estimation of galaxy cluster masses is essential for their use in cosmological and astrophysical studies. We studied the accuracy of the optical richness obtained by our RedGOLD cluster detection algorithm tep{licitra2016a, licitra2016b} as a mass proxy, using weak lensing and X-ray mass measurements. We measured stacked weak lensing cluster masses for a sample of 1323 galaxy clusters in the Canada-France-Hawaii Telescope Legacy Survey W1 and the Next Generation Virgo Cluster Survey at 0.2z<0.5, in the optical richness range 10-70. We tested different weak lensing mass models that account for miscentering, non-weak shear, the two-halo term, the contribution of the Brightest Cluster Galaxy, and the intrinsic scatter in the mass-richness relation. We calculated the coefficients of the mass-richness relation, and of the scaling relations between the lensing mass and X-ray mass proxies.

  5. 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.

  6. The Strong Gravitationally Lensed Herschel Galaxy HLock01: Optical Spectroscopy Reveals a Close Galaxy Merger with Evidence of Inflowing Gas

    Science.gov (United States)

    Marques-Chaves, Rui; Pérez-Fournon, Ismael; Gavazzi, Raphael; Martínez-Navajas, Paloma I.; Riechers, Dominik; Rigopoulou, Dimitra; Cabrera-Lavers, Antonio; Clements, David L.; Cooray, Asantha; Farrah, Duncan; Ivison, Rob J.; Jiménez-Ángel, Camilo E.; Nayyeri, Hooshang; Oliver, Seb; Omont, Alain; Scott, Douglas; Shu, Yiping; Wardlow, Julie

    2018-02-01

    The submillimeter galaxy (SMG) HERMES J105751.1+573027 (hereafter HLock01) at z = 2.9574 ± 0.0001 is one of the brightest gravitationally lensed sources discovered in the Herschel Multi-tiered Extragalactic Survey. Apart from the high flux densities in the far-infrared, it is also extremely bright in the rest-frame ultraviolet (UV), with a total apparent magnitude m UV ≃ 19.7 mag. We report here deep spectroscopic observations with the Gran Telescopio Canarias of the optically bright lensed images of HLock01. Our results suggest that HLock01 is a merger system composed of the Herschel-selected SMG and an optically bright Lyman break-like galaxy (LBG), separated by only 3.3 kpc in projection. While the SMG appears very massive (M * ≃ 5 × 1011 M ⊙), with a highly extinguished stellar component (A V ≃ 4.3 ), the LBG is a young, lower-mass (M * ≃ 1 × 1010 M ⊙), but still luminous (10× {L}UV}* ) satellite galaxy. Detailed analysis of the high signal-to-noise ratio (S/N) rest-frame UV spectrum of the LBG shows complex kinematics of the gas, exhibiting both blueshifted and redshifted absorption components. While the blueshifted component is associated with strong galactic outflows from the massive stars in the LBG, as is common in most star-forming galaxies, the redshifted component may be associated with gas inflow seen along a favorable sightline to the LBG. We also find evidence of an extended gas reservoir around HLock01 at an impact parameter of 110 kpc, through the detection of C II λλ1334 absorption in the red wing of a bright Lyα emitter at z ≃ 3.327. The data presented here highlight the power of gravitational lensing in high S/N studies to probe deeply into the physics of high-z star-forming galaxies.

  7. A dusty star-forming galaxy at z = 6 revealed by strong gravitational lensing

    Science.gov (United States)

    Zavala, Jorge A.; Montaña, Alfredo; Hughes, David H.; Yun, Min S.; Ivison, R. J.; Valiante, Elisabetta; Wilner, David; Spilker, Justin; Aretxaga, Itziar; Eales, Stephen; Avila-Reese, Vladimir; Chávez, Miguel; Cooray, Asantha; Dannerbauer, Helmut; Dunlop, James S.; Dunne, Loretta; Gómez-Ruiz, Arturo I.; Michałowski, Michał J.; Narayanan, Gopal; Nayyeri, Hooshang; Oteo, Ivan; Rosa González, Daniel; Sánchez-Argüelles, David; Schloerb, F. Peter; Serjeant, Stephen; Smith, Matthew W. L.; Terlevich, Elena; Vega, Olga; Villalba, Alan; van der Werf, Paul; Wilson, Grant W.; Zeballos, Milagros

    2018-01-01

    Since their discovery, submillimetre-selected galaxies1,2 have revolutionized the field of galaxy formation and evolution. From the hundreds of square degrees mapped at submillimetre wavelengths3-5, only a handful of sources have been confirmed to lie at z > 5 (refs 6-10) and only two at z ≥ 6 (refs 11,12). All of these submillimetre galaxies are rare examples of extreme starburst galaxies with star formation rates of ≳1,000 M⊙ yr-1 and therefore are not representative of the general population of dusty star-forming galaxies. Consequently, our understanding of the nature of these sources, at the earliest epochs, is still incomplete. Here, we report the spectroscopic identification of a gravitationally amplified (μ = 9.3 ± 1.0) dusty star-forming galaxy at z = 6.027. After correcting for gravitational lensing, we derive an intrinsic less-extreme star formation rate of 380 ± 50 M⊙ yr-1 for this source and find that its gas and dust properties are similar to those measured for local ultra luminous infrared galaxies, extending the local trends to a poorly explored territory in the early Universe. The star-formation efficiency of this galaxy is similar to those measured in its local analogues13, despite a 12 Gyr difference in cosmic time.

  8. A new method to measure galaxy bias by combining the density and weak lensing fields

    Energy Technology Data Exchange (ETDEWEB)

    Pujol, Arnau; Chang, Chihway; Gaztañaga, Enrique; Amara, Adam; Refregier, Alexandre; Bacon, David J.; Carretero, Jorge; Castander, Francisco J.; Crocce, Martin; Fosalba, Pablo; Manera, Marc; Vikram, Vinu

    2016-07-29

    We present a new method to measure redshift-dependent galaxy bias by combining information from the galaxy density field and the weak lensing field. This method is based on the work of Amara et al., who use the galaxy density field to construct a bias-weighted convergence field κg. The main difference between Amara et al.'s work and our new implementation is that here we present another way to measure galaxy bias, using tomography instead of bias parametrizations. The correlation between κg and the true lensing field κ allows us to measure galaxy bias using different zero-lag correlations, such as <κgκ>/<κκ> or <κgκg>/<κgκ>. Our method measures the linear bias factor on linear scales, under the assumption of no stochasticity between galaxies and matter. We use the Marenostrum Institut de Ciències de l'Espai (MICE) simulation to measure the linear galaxy bias for a flux-limited sample (i < 22.5) in tomographic redshift bins using this method. This article is the first that studies the accuracy and systematic uncertainties associated with the implementation of the method and the regime in which it is consistent with the linear galaxy bias defined by projected two-point correlation functions (2PCF). We find that our method is consistent with a linear bias at the per cent level for scales larger than 30 arcmin, while non-linearities appear at smaller scales. This measurement is a good complement to other measurements of bias, since it does not depend strongly on σ8 as do the 2PCF measurements. We will apply this method to the Dark Energy Survey Science Verification data in a follow-up article.

  9. A gravitationally lensed starburst galaxy at z=1.03 detected by SOFIA/HAWC+

    Science.gov (United States)

    Brown, Arianna; Ma, Jingzhe; Cooray, Asantha; Nayyeri, Hooshang; Timmons, Nicholas

    2018-01-01

    We present a high S/N~20 detection at 89 micron (in 15 mins) of the Herschel-selected gravitationally lensed starburst galaxy HATLASJ1429-0028 with the High-resolution Airborne Wideband Camera-plus (HAWC+) onboard the Stratospheric Observatory for Infrared Astronomy (SOFIA). The spectacular lensing system consists of an edge-on foreground disk galaxy at z=0.22 and a nearly complete Einstein ring of an intrinsic ultra-luminous infrared galaxy at z=1.03. Is this high luminosity powered by pure star formation (SF) or an active galactic nucleus (AGN)? Previous nebular line diagnostics indicate that it is star-formation dominated. SOFIA/HAWC+ allows the broad-band spectral energy distribution of the galaxy to be studied between 20 - 100 micron, which is an important wavelength range for further constraining the fractional AGN contribution to the total IR luminosity. Multi-wavelength SED modeling constrains the AGN fraction to be SOFIA/HAWC+ for distant galaxy studies and the potential to decompose SF/AGN that cannot be obtained with other current facilities.

  10. 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.

  11. 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.

  12. 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.

  13. LBT/LUCIFER OBSERVATIONS OF THE z ∼ 2 LENSED GALAXY J0900+2234

    International Nuclear Information System (INIS)

    Bian Fuyan; Fan Xiaohui; Bechtold, Jill; McGreer, Ian D.; Just, Dennis W.; Sand, David J.; Green, Richard F.; Thompson, David; Peng, Chien Y.; Seifert, Walter; Ageorges, Nancy; Buschkamp, Peter; Juette, Marcus; Knierim, Volker

    2010-01-01

    We present rest-frame optical images and spectra of the gravitationally lensed, star-forming galaxy J0900+2234 (z = 2.03). The observations were performed with the newly commissioned LUCIFER1 near-infrared (NIR) instrument mounted on the Large Binocular Telescope. We fitted lens models to the rest-frame optical images and found that the galaxy has an intrinsic effective radius of 7.4 ± 0.8 kpc with a lens magnification factor of about 5 for the A and B components. We also discovered a new arc belonging to another lensed high-z source galaxy, which makes this lens system a potential double Einstein ring system. Using the high signal-to-noise ratio rest-frame spectra covered by the H + K band, we detected Hβ, [O III], Hα, [N II], and [S II] emission lines. Detailed physical properties of this high-z galaxy were derived. The extinction toward the ionized H II regions (E g (B - V)) was computed from the flux ratio of Hα and Hβ and appears to be much higher than that toward the stellar continuum (E s (B - V)), derived from the optical and NIR broadband photometry fitting. The metallicity was estimated using N2 and O3N2 indices. It is in the range of 1/5 - 1/3 solar abundance, which is much lower than for typical z ∼ 2 star-forming galaxies. From the flux ratio of [S II]λ6717 and [S II]λ6732, we found that the electron number density of the H II regions in the high-z galaxy was ≅1000 cm -3 , consistent with other z ∼ 2 galaxies but much higher than that in local H II regions. The star formation rate was estimated via the Hα luminosity, after correction for the lens magnification, to be about 365 ± 69 M sun yr -1 . Combining the FWHM of Hα emission lines and the half-light radius, we found that the dynamical mass of the lensed galaxy is (5.8 ± 0.9) x 10 10 M sun . The gas mass is (5.1 ± 1.1) x 10 10 M sun from the Hα flux surface density using global Kennicutt-Schmidt law, indicating a very high gas fraction of 0.79 ± 0.19 in J0900+2234.

  14. 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.

  15. 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

  16. 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.

  17. Dark Energy Survey Year 1 Results: Redshift distributions of the weak lensing source galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Hoyle, B.; et al.

    2017-08-04

    We describe the derivation and validation of redshift distribution estimates and their uncertainties for the galaxies used as weak lensing sources in the Dark Energy Survey (DES) Year 1 cosmological analyses. The Bayesian Photometric Redshift (BPZ) code is used to assign galaxies to four redshift bins between z=0.2 and 1.3, and to produce initial estimates of the lensing-weighted redshift distributions $n^i_{PZ}(z)$ for bin i. Accurate determination of cosmological parameters depends critically on knowledge of $n^i$ but is insensitive to bin assignments or redshift errors for individual galaxies. The cosmological analyses allow for shifts $n^i(z)=n^i_{PZ}(z-\\Delta z^i)$ to correct the mean redshift of $n^i(z)$ for biases in $n^i_{\\rm PZ}$. The $\\Delta z^i$ are constrained by comparison of independently estimated 30-band photometric redshifts of galaxies in the COSMOS field to BPZ estimates made from the DES griz fluxes, for a sample matched in fluxes, pre-seeing size, and lensing weight to the DES weak-lensing sources. In companion papers, the $\\Delta z^i$ are further constrained by the angular clustering of the source galaxies around red galaxies with secure photometric redshifts at 0.15

  18. 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.

  19. Evidence for massive neutrinos from cosmic microwave background and lensing observations.

    Science.gov (United States)

    Battye, Richard A; Moss, Adam

    2014-02-07

    We discuss whether massive neutrinos (either active or sterile) can reconcile some of the tensions within cosmological data that have been brought into focus by the recently released Planck data. We point out that a discrepancy is present when comparing the primary CMB and lensing measurements both from the CMB and galaxy lensing data using CFHTLenS, similar to that which arises when comparing CMB measurements and SZ cluster counts. A consistent picture emerges and including a prior for the cluster constraints and BAOs we find that for an active neutrino model with three degenerate neutrinos, ∑m(ν)=(0.320±0.081)  eV, whereas for a sterile neutrino, in addition to 3 neutrinos with a standard hierarchy and ∑m(ν)=0.06  eV, m(ν,sterile)(eff)=(0.450±0.124)  eV and ΔN(eff)=0.45±0.23. In both cases there is a significant detection of modification to the neutrino sector from the standard model and in the case of the sterile neutrino it is possible to reconcile the BAO and local H0 measurements. However, a caveat to our result is some internal tension between the CMB and lensing and cluster observations, and the masses are in excess of those estimated from the shape of the matter power spectrum from galaxy surveys.

  20. HERSCHEL EXTREME LENSING LINE OBSERVATIONS: [C ii] VARIATIONS IN GALAXIES AT REDSHIFTS z = 1–3

    Energy Technology Data Exchange (ETDEWEB)

    Malhotra, Sangeeta; Rhoads, James E.; Yang, Huan [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Finkelstein, K.; Finkelstein, Steven [University of Texas, Austin, TX 78712 (United States); Carilli, Chris [National Radio Astronomy Observatory, Socorro, NM (United States); Combes, Françoise [Observatoire de Paris, LERMA, CNRS, 61 Avenue de l’Observatoire, F-75014 Paris (France); Dassas, Karine; Guillard, Pierre; Nesvadba, Nicole [Institut d’Astrophysique Spatiale, Centre Universitaire d’Orsay (France); Frye, Brenda [Steward Observatory, University of Arizona, Tucson, AZ (United States); Gerin, Maryvonne [LERMA,24 rue Lhomond, F-75231 Paris Cedex 05 (France); Rigby, Jane [NASA Goddard Space Flight Center, Greenbelt, MD (United States); Shin, Min-Su [Oxford University, Oxford, OX1 3PA (United Kingdom); Spaans, Marco [Kapteyn Astronomical Institute, University of Groningen, Groningen (Netherlands); Strauss, Michael A. [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544 (United States); Papovich, Casey, E-mail: malhotra@asu.edu [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics, Texas A and M University, College Station, TX 77843 (United States)

    2017-01-20

    We observed the [C ii] line in 15 lensed galaxies at redshifts 1 < z < 3 using HIFI on the Herschel Space Observatory and detected 14/15 galaxies at 3 σ or better. High magnifications enable even modestly luminous galaxies to be detected in [C ii] with Herschel . The [C ii] luminosity in this sample ranges from 8 × 10{sup 7} L {sub ⊙} to 3.7 × 10{sup 9} L {sub ⊙} (after correcting for magnification), confirming that [C ii] is a strong tracer of the ISM at high redshifts. The ratio of the [C ii] line to the total far-infrared (FIR) luminosity serves as a measure of the ratio of gas to dust cooling and thus the efficiency of the grain photoelectric heating process. It varies between 3.3% and 0.09%. We compare the [C ii]/FIR ratio to that of galaxies at z = 0 and at high redshifts and find that they follow similar trends. The [C ii]/FIR ratio is lower for galaxies with higher dust temperatures. This is best explained if increased UV intensity leads to higher FIR luminosity and dust temperatures, but gas heating does not rise due to lower photoelectric heating efficiency. The [C ii]/FIR ratio shows weaker correlation with FIR luminosity. At low redshifts highly luminous galaxies tend to have warm dust, so the effects of dust temperature and luminosity are degenerate. Luminous galaxies at high redshifts show a range of dust temperatures, showing that [C ii]/FIR correlates most strongly with dust temperature. The [C ii] to mid-IR ratio for the HELLO sample is similar to the values seen for low-redshift galaxies, indicating that small grains and PAHs dominate the heating in the neutral ISM, although some of the high [CII]/FIR ratios may be due to turbulent heating.

  1. HERSCHEL EXTREME LENSING LINE OBSERVATIONS: [C ii] VARIATIONS IN GALAXIES AT REDSHIFTS z = 1–3

    International Nuclear Information System (INIS)

    Malhotra, Sangeeta; Rhoads, James E.; Yang, Huan; Finkelstein, K.; Finkelstein, Steven; Carilli, Chris; Combes, Françoise; Dassas, Karine; Guillard, Pierre; Nesvadba, Nicole; Frye, Brenda; Gerin, Maryvonne; Rigby, Jane; Shin, Min-Su; Spaans, Marco; Strauss, Michael A.; Papovich, Casey

    2017-01-01

    We observed the [C ii] line in 15 lensed galaxies at redshifts 1 < z < 3 using HIFI on the Herschel Space Observatory and detected 14/15 galaxies at 3 σ or better. High magnifications enable even modestly luminous galaxies to be detected in [C ii] with Herschel . The [C ii] luminosity in this sample ranges from 8 × 10 7 L ⊙ to 3.7 × 10 9 L ⊙ (after correcting for magnification), confirming that [C ii] is a strong tracer of the ISM at high redshifts. The ratio of the [C ii] line to the total far-infrared (FIR) luminosity serves as a measure of the ratio of gas to dust cooling and thus the efficiency of the grain photoelectric heating process. It varies between 3.3% and 0.09%. We compare the [C ii]/FIR ratio to that of galaxies at z = 0 and at high redshifts and find that they follow similar trends. The [C ii]/FIR ratio is lower for galaxies with higher dust temperatures. This is best explained if increased UV intensity leads to higher FIR luminosity and dust temperatures, but gas heating does not rise due to lower photoelectric heating efficiency. The [C ii]/FIR ratio shows weaker correlation with FIR luminosity. At low redshifts highly luminous galaxies tend to have warm dust, so the effects of dust temperature and luminosity are degenerate. Luminous galaxies at high redshifts show a range of dust temperatures, showing that [C ii]/FIR correlates most strongly with dust temperature. The [C ii] to mid-IR ratio for the HELLO sample is similar to the values seen for low-redshift galaxies, indicating that small grains and PAHs dominate the heating in the neutral ISM, although some of the high [CII]/FIR ratios may be due to turbulent heating.

  2. ACCOUNTING FOR COSMIC VARIANCE IN STUDIES OF GRAVITATIONALLY LENSED HIGH-REDSHIFT GALAXIES IN THE HUBBLE FRONTIER FIELD CLUSTERS

    International Nuclear Information System (INIS)

    Robertson, Brant E.; Stark, Dan P.; Ellis, Richard S.; Dunlop, James S.; McLure, Ross J.; 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 show that the cosmic variance uncertainty of the high-redshift population viewed through the Hubble Space Telescope Frontier Field cluster Abell 2744 increases from ∼35% at redshift z ∼ 7 to ≳ 65% at z ∼ 10. Previous studies of high-redshift galaxies identified in the Frontier Fields have underestimated the cosmic variance uncertainty that will affect the ultimate constraints on both the faint-end slope of the high-redshift luminosity function and the cosmic star formation rate density, key goals of the Frontier Field program

  3. 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

  4. Confirmation of general relativity on large scales from weak lensing and galaxy velocities.

    Science.gov (United States)

    Reyes, Reinabelle; Mandelbaum, Rachel; Seljak, Uros; Baldauf, Tobias; Gunn, James E; Lombriser, Lucas; Smith, Robert E

    2010-03-11

    Although general relativity underlies modern cosmology, its applicability on cosmological length scales has yet to be stringently tested. Such a test has recently been proposed, using a quantity, E(G), that combines measures of large-scale gravitational lensing, galaxy clustering and structure growth rate. The combination is insensitive to 'galaxy bias' (the difference between the clustering of visible galaxies and invisible dark matter) and is thus robust to the uncertainty in this parameter. Modified theories of gravity generally predict values of E(G) different from the general relativistic prediction because, in these theories, the 'gravitational slip' (the difference between the two potentials that describe perturbations in the gravitational metric) is non-zero, which leads to changes in the growth of structure and the strength of the gravitational lensing effect. Here we report that E(G) = 0.39 +/- 0.06 on length scales of tens of megaparsecs, in agreement with the general relativistic prediction of E(G) approximately 0.4. The measured value excludes a model within the tensor-vector-scalar gravity theory, which modifies both Newtonian and Einstein gravity. However, the relatively large uncertainty still permits models within f(R) theory, which is an extension of general relativity. A fivefold decrease in uncertainty is needed to rule out these models.

  5. Searching in GaBoDS deep survey for clusters of galaxies by weak gravitational lensing

    Directory of Open Access Journals (Sweden)

    M Rahimi

    2011-06-01

    Full Text Available The aim of the present work is detection of galaxy clusters based on weak gravitational lensing method. We apply mass aperture statistics method to 0.32 square degrees data obtained with the WFI@MPG/ESO 2.2 m telescope and detect mass peaks based on their mass not the luminosity. So by the application of proper filter function, shear profile and mass map are produced. Finally mass peaks with higher detection significance are extracted. In future works, redshift of these mass concentrations and so their mass can be obtained.‎

  6. 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.

  7. KiDS+GAMA: Cosmology constraints from a joint analysis of cosmic shear, galaxy-galaxy lensing and angular clustering

    Science.gov (United States)

    van Uitert, Edo; Joachimi, Benjamin; Joudaki, Shahab; Amon, Alexandra; Heymans, Catherine; Köhlinger, Fabian; Asgari, Marika; Blake, Chris; Choi, Ami; Erben, Thomas; Farrow, Daniel J.; Harnois-Déraps, Joachim; Hildebrandt, Hendrik; Hoekstra, Henk; Kitching, Thomas D.; Klaes, Dominik; Kuijken, Konrad; Merten, Julian; Miller, Lance; Nakajima, Reiko; Schneider, Peter; Valentijn, Edwin; Viola, Massimo

    2018-03-01

    We present cosmological parameter constraints from a joint analysis of three cosmological probes: the tomographic cosmic shear signal in ˜450 deg2 of data from the Kilo Degree Survey (KiDS), the galaxy-matter cross-correlation signal of galaxies from the Galaxies And Mass Assembly (GAMA) survey determined with KiDS weak lensing, and the angular correlation function of the same GAMA galaxies. We use fast power spectrum estimators that are based on simple integrals over the real-space correlation functions, and show that they are practically unbiased over relevant angular frequency ranges. We test our full pipeline on numerical simulations that are tailored to KiDS and retrieve the input cosmology. By fitting different combinations of power spectra, we demonstrate that the three probes are internally consistent. For all probes combined, we obtain S_8≡ σ _8 √{Ω _m/0.3}=0.800_{-0.027}^{+0.029}, consistent with Planck and the fiducial KiDS-450 cosmic shear correlation function results. Marginalising over wide priors on the mean of the tomographic redshift distributions yields consistent results for S8 with an increase of 28% in the error. The combination of probes results in a 26% reduction in uncertainties of S8 over using the cosmic shear power spectra alone. The main gain from these additional probes comes through their constraining power on nuisance parameters, such as the galaxy intrinsic alignment amplitude or potential shifts in the redshift distributions, which are up to a factor of two better constrained compared to using cosmic shear alone, demonstrating the value of large-scale structure probe combination.

  8. The stellar-to-halo mass relation of GAMA galaxies from 100 deg2 of KiDS weak lensing data

    NARCIS (Netherlands)

    van Uitert, Edo; Cacciato, Marcello; Hoekstra, Henk; Brouwer, Margot; Sifón, Cristóbal; Viola, Massimo; Baldry, Ivan; Bland-Hawthorn, Joss; Brough, Sarah; Brown, M. J. I.; Choi, Ami; Driver, Simon P.; Erben, Thomas; Heymans, Catherine; Hildebrandt, Hendrik; Joachimi, Benjamin; Kuijken, Konrad; Liske, Jochen; Loveday, Jon; Mc Farland, J.; Miller, Lance; Nakajima, Reiko; Peacock, John; Radovich, Mario; Robotham, A. S. G.; Schneider, Peter; Sikkema, Gert; Taylor, Edward N.; Verdoes Kleijn, Gijs

    2016-01-01

    We study the stellar-to-halo mass relation of central galaxies in the range 9.7 10(M*/h- 2 M⊙) ) ) 2 of KiDS data to study the lensing signal around galaxies for which spectroscopic redshifts and stellar masses were determined by GAMA. We show that lensing alone results in poor constraints on the

  9. The Sloan Lens ACS Survey. XI. Beyond Hubble Resolution : Size, Luminosity, and Stellar Mass of Compact Lensed Galaxies at Intermediate Redshift

    NARCIS (Netherlands)

    Newton, Elisabeth R.; Marshall, Philip J.; Treu, Tommaso; Auger, Matthew W.; Gavazzi, Raphaeel; Bolton, Adam S.; Koopmans, Leon V. E.; Moustakas, Leonidas A.

    We exploit the strong lensing effect to explore the properties of intrinsically faint and compact galaxies at intermediate redshift (z(s) similar or equal to 0.4-0.8) at the highest possible resolution at optical wavelengths. Our sample consists of 46 strongly lensed emission line galaxies (ELGs)

  10. STELLAR MASSES AND STAR FORMATION RATES OF LENSED, DUSTY, STAR-FORMING GALAXIES FROM THE SPT SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jingzhe; Gonzalez, Anthony H. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Spilker, J. S.; Marrone, D. P. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Strandet, M. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69 D-53121 Bonn (Germany); Ashby, M. L. N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Aravena, M. [Núcleo de Astronomía, Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército 441, Santiago (Chile); Béthermin, M.; Breuck, C. de; Gullberg, B. [European Southern Observatory, Karl Schwarzschild Straße 2, D-85748 Garching (Germany); Bothwell, M. S. [Cavendish Laboratory, University of Cambridge, JJ Thompson Avenue, Cambridge CB3 0HA (United Kingdom); Brodwin, M. [Department of Physics and Astronomy, University of Missouri, 5110 Rockhill Road, Kansas City, MO 64110 (United States); Chapman, S. C. [Dalhousie University, Halifax, Nova Scotia (Canada); Fassnacht, C. D. [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Greve, T. R. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Hezaveh, Y. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States); Malkan, M. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States); Saliwanchik, B. R., E-mail: jingzhema@ufl.edu [Department of Physics, Case Western Reserve University, Cleveland, OH 44106 (United States); and others

    2015-10-10

    To understand cosmic mass assembly in the universe at early epochs, we primarily rely on measurements of the stellar masses and star formation rates (SFRs) of distant galaxies. In this paper, we present stellar masses and SFRs of six high-redshift (2.8 ≤ z ≤ 5.7) dusty, star-forming galaxies (DSFGs) that are strongly gravitationally lensed by foreground galaxies. These sources were first discovered by the South Pole Telescope (SPT) at millimeter wavelengths and all have spectroscopic redshifts and robust lens models derived from Atacama Large Millimeter/submillimeter Array observations. We have conducted follow-up observations to obtain multi-wavelength imaging data using the Hubble Space Telescope (HST), Spitzer, Herschel, and the Atacama Pathfinder EXperiment. We use the high-resolution HST/Wide Field Camera 3 images to disentangle the background source from the foreground lens in Spitzer/IRAC data. The detections and upper limits provide important constraints on the spectral energy distributions (SEDs) for these DSFGs, yielding stellar masses, IR luminosities, and SFRs. The SED fits of six SPT sources show that the intrinsic stellar masses span a range more than one order of magnitude with a median value ∼5 ×10{sup 10} M{sub ⊙}. The intrinsic IR luminosities range from 4 × 10{sup 12} L{sub ⊙} to 4 × 10{sup 13} L{sub ⊙}. They all have prodigious intrinsic SFRs of 510–4800 M{sub ⊙} yr{sup −1}. Compared to the star-forming main sequence (MS), these six DSFGs have specific SFRs that all lie above the MS, including two galaxies that are a factor of 10 higher than the MS. Our results suggest that we are witnessing ongoing strong starburst events that may be driven by major mergers.

  11. The inner mass power spectrum of galaxies using strong gravitational lensing: beyond linear approximation

    Science.gov (United States)

    Chatterjee, Saikat; Koopmans, Léon V. E.

    2018-02-01

    In the last decade, the detection of individual massive dark matter sub-haloes has been possible using potential correction formalism in strong gravitational lens imaging. Here, we propose a statistical formalism to relate strong gravitational lens surface brightness anomalies to the lens potential fluctuations arising from dark matter distribution in the lens galaxy. We consider these fluctuations as a Gaussian random field in addition to the unperturbed smooth lens model. This is very similar to weak lensing formalism and we show that in this way we can measure the power spectrum of these perturbations to the potential. We test the method by applying it to simulated mock lenses of different geometries and by performing an MCMC analysis of the theoretical power spectra. This method can measure density fluctuations in early type galaxies on scales of 1-10 kpc at typical rms levels of a per cent, using a single lens system observed with the Hubble Space Telescope with typical signal-to-noise ratios obtained in a single orbit.

  12. Gravitational lensing reveals extreme dust-obscured star formation in quasar host galaxies

    Science.gov (United States)

    Stacey, H. R.; McKean, J. P.; Robertson, N. C.; Ivison, R. J.; Isaak, K. G.; Schleicher, D. R. G.; van der Werf, P. P.; Baan, W. A.; Alba, A. Berciano; Garrett, M. A.; Loenen, A. F.

    2018-02-01

    We have observed 104 gravitationally-lensed quasars at z ˜ 1-4 with Herschel/SPIRE, the largest such sample ever studied. By targeting gravitational lenses, we probe intrinsic far-infrared (FIR) luminosities and star formation rates (SFRs) more typical of the population than the extremely luminous sources that are otherwise accessible. We detect 72 objects with Herschel/SPIRE and find 66 percent (69 sources) of the sample have spectral energy distributions (SEDs) characteristic of dust emission. For 53 objects with sufficiently constrained SEDs, we find a median effective dust temperature of 38^{+12}_{-5} K. By applying the radio-infrared correlation, we find no evidence for an FIR excess which is consistent with star-formation-heated dust. We derive a median magnification-corrected FIR luminosity of 3.6^{+4.8}_{-2.4} × 10^{11} L_{⊙} and median SFR of 120^{+160}_{-80} M_{⊙} yr^{-1} for 94 quasars with redshifts. We find ˜10 percent of our sample have FIR properties similar to typical dusty star-forming galaxies at z ˜ 2-3 and a range of SFRs statistically-significant difference in the FIR luminosities of quasars in our sample with a radio excess relative to the radio-infrared correlation. Synchrotron emission is found to dominate at FIR wavelengths for <15 percent of those sources classified as powerful radio galaxies.

  13. Halo ellipticity of GAMA galaxy groups from KiDS weak lensing

    Science.gov (United States)

    van Uitert, Edo; Hoekstra, Henk; Joachimi, Benjamin; Schneider, Peter; Bland-Hawthorn, Joss; Choi, Ami; Erben, Thomas; Heymans, Catherine; Hildebrandt, Hendrik; Hopkins, Andrew M.; Klaes, Dominik; Kuijken, Konrad; Nakajima, Reiko; Napolitano, Nicola R.; Schrabback, Tim; Valentijn, Edwin; Viola, Massimo

    2017-06-01

    We constrain the average halo ellipticity of ˜2600 galaxy groups from the Galaxy And Mass Assembly (GAMA) survey, using the weak gravitational lensing signal measured from the overlapping Kilo Degree Survey (KiDS). To do so, we quantify the azimuthal dependence of the stacked lensing signal around seven different proxies for the orientation of the dark matter distribution, as it is a priori unknown which one traces the orientation best. On small scales, the major axis of the brightest group/cluster member (BCG) provides the best proxy, leading to a clear detection of an anisotropic signal. In order to relate that to a halo ellipticity, we have to adopt a model density profile. We derive new expressions for the quadrupole moments of the shear field given an elliptical model surface mass density profile. Modelling the signal with an elliptical Navarro-Frenk-White profile on scales R < 250 kpc, and assuming that the BCG is perfectly aligned with the dark matter, we find an average halo ellipticity of ɛh = 0.38 ± 0.12, in fair agreement with results from cold dark matter only simulations. On larger scales, the lensing signal around the BCGs becomes isotropic and the distribution of group satellites provides a better proxy for the halo's orientation instead, leading to a 3σ-4σ detection of a non-zero halo ellipticity at 250 < R < 750 kpc. Our results suggest that the distribution of stars enclosed within a certain radius forms a good proxy for the orientation of the dark matter within that radius, which has also been observed in hydrodynamical simulations.

  14. Modelling high resolution ALMA observations of strongly lensed highly star forming galaxies detected by Herscheltype="fn" rid="fn1" />

    Science.gov (United States)

    Dye, S.; Furlanetto, C.; Dunne, L.; Eales, S. A.; Negrello, M.; Nayyeri, H.; van der Werf, P. P.; Serjeant, S.; Farrah, D.; Michałowski, M. J.; Baes, M.; Marchetti, L.; Cooray, A.; Riechers, D. A.; Amvrosiadis, A.

    2018-02-01

    We have modelled ˜0.1 arcsec resolution ALMA imaging of six strong gravitationally lensed galaxies detected by the Herschel Space Observatory. Our modelling recovers mass properties of the lensing galaxies and, by determining magnification factors, intrinsic properties of the lensed sub-millimetre sources. We find that the lensed galaxies all have high ratios of star formation rate to dust mass, consistent with or higher than the mean ratio for high redshift sub-millimetre galaxies and low redshift ultra-luminous infra-red galaxies. Source reconstruction reveals that most galaxies exhibit disturbed morphologies. Both the cleaned image plane data and the directly observed interferometric visibilities have been modelled, enabling comparison of both approaches. In the majority of cases, the recovered lens models are consistent between methods, all six having mass density profiles that are close to isothermal. However, one system with poor signal to noise shows mildly significant differences.

  15. The Double Galaxy Cluster A2465. III. X-Ray and Weak-lensing Observations

    Science.gov (United States)

    Wegner, Gary A.; Umetsu, Keiichi; Molnar, Sandor M.; Nonino, Mario; Medezinski, Elinor; Andrade-Santos, Felipe; Bogdan, Akos; Lovisari, Lorenzo; Forman, William R.; Jones, Christine

    2017-07-01

    We report Chandra X-ray observations and optical weak-lensing measurements from Subaru/Suprime-Cam images of the double galaxy cluster A2465 (z = 0.245). The X-ray brightness data are fit to a β model to obtain the radial gas density profiles of the northeast (NE) and southwest (SW) subcomponents, which are seen to differ in structure. We determine core radii, central temperatures, the gas masses within r 500c, and the total masses for the broader NE and sharper SW components assuming hydrostatic equilibrium. There is no large X-ray excess between the two components. The central entropy of the NE subcluster is about two times higher than the SW. Along with its structural properties and an apparent radio halo that is a sign of a merger, this suggests that the NE component has undergone merging on its own. The weak-lensing analysis gives virial masses for each substructure, which compare well with earlier dynamical results. The derived outer mass contours of the SW sub-component from weak lensing are more irregular and extended than those of the NE. Although there is a weak enhancement and small offsets between X-ray gas and mass centers from weak lensing, the lack of large amounts of gas between the two subclusters indicates that A2465 is in a pre-merger state. We discuss star formation enhancement in this system resulting from its dynamics and shock-induced star formation scenarios. A dynamical model that is consistent with the observed cluster data, based on the FLASH program and the radial infall model, is constructed, where the subclusters currently separated by ˜1.2 Mpc are approaching each other at ˜2000 km s-1 and will meet in ˜0.4 Gyr. Based in part on data collected at the Subaru Telescope, which is operated by the National Astronomical Society of Japan.

  16. The Double Galaxy Cluster A2465. III. X-Ray and Weak-lensing Observations

    Energy Technology Data Exchange (ETDEWEB)

    Wegner, Gary A. [Department of Physics and Astronomy, 6127 Wilder Laboratory, Hanover, NH 03745 (United States); Umetsu, Keiichi; Molnar, Sandor M. [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, 34143 Trieste (Italy); Medezinski, Elinor [Department of Astrophysical Sciences, 4 Ivy Lane, Princeton, NJ 08544 (United States); Andrade-Santos, Felipe; Bogdan, Akos; Lovisari, Lorenzo; Forman, William R.; Jones, Christine, E-mail: gary.wegner@dartmouth.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2017-07-20

    We report Chandra X-ray observations and optical weak-lensing measurements from Subaru/Suprime-Cam images of the double galaxy cluster A2465 ( z = 0.245). The X-ray brightness data are fit to a β model to obtain the radial gas density profiles of the northeast (NE) and southwest (SW) subcomponents, which are seen to differ in structure. We determine core radii, central temperatures, the gas masses within r {sub 500c}, and the total masses for the broader NE and sharper SW components assuming hydrostatic equilibrium. There is no large X-ray excess between the two components. The central entropy of the NE subcluster is about two times higher than the SW. Along with its structural properties and an apparent radio halo that is a sign of a merger, this suggests that the NE component has undergone merging on its own. The weak-lensing analysis gives virial masses for each substructure, which compare well with earlier dynamical results. The derived outer mass contours of the SW sub-component from weak lensing are more irregular and extended than those of the NE. Although there is a weak enhancement and small offsets between X-ray gas and mass centers from weak lensing, the lack of large amounts of gas between the two subclusters indicates that A2465 is in a pre-merger state. We discuss star formation enhancement in this system resulting from its dynamics and shock-induced star formation scenarios. A dynamical model that is consistent with the observed cluster data, based on the FLASH program and the radial infall model, is constructed, where the subclusters currently separated by ∼1.2 Mpc are approaching each other at ∼2000 km s{sup −1} and will meet in ∼0.4 Gyr.

  17. Measuring the hydrostatic mass bias in galaxy clusters by combining Sunyaev-Zel'dovich and CMB lensing data

    Science.gov (United States)

    Hurier, G.; Angulo, R. E.

    2018-02-01

    The cosmological parameters preferred by the cosmic microwave background (CMB) primary anisotropies predict many more galaxy clusters than those that have been detected via the thermal Sunyaev-Zeldovich (tSZ) effect. This discrepancy has attracted considerable attention since it might be evidence of physics beyond the simplest ΛCDM model. However, an accurate and robust calibration of the mass-observable relation for clusters is necessary for the comparison, which has been proven difficult to obtain so far. Here, we present new constraints on the mass-pressure relation by combining tSZ and CMB lensing measurements of optically selected clusters. Consequently, our galaxy cluster sample is independent of the data employed to derive cosmological constrains. We estimate an average hydrostatic mass bias of b = 0.26 ± 0.07, with no significant mass or redshift evolution. This value greatly reduces the discrepancy between the predictions of ΛCDM and the observed abundance of tSZ clusters but agrees with recent estimates from tSZ clustering. On the other hand, our value for b is higher than the predictions from hydrodynamical simulations. This suggests mechanisms that drive large departures from hydrostatic equilibrium and that are not included in the latest simulations, and/or unaccounted systematic errors such as biases in the cluster catalogue that are due to the optical selection.

  18. The Atacama Cosmology Telescope: Cross-Correlation of Cosmic Microwave Background Lensing and Quasars

    Science.gov (United States)

    Sherwin, Blake D; Das, Sudeep; Haijian, Amir; Addison, Graeme; Bond, Richard; Crichton, Devin; Devlin, Mark J.; Dunkley, Joanna; Gralla, Megan B.; Halpern, Mark; hide

    2012-01-01

    We measure the cross-correlation of Atacama cosmology telescope cosmic microwave background (CMB) lensing convergence maps with quasar maps made from the Sloan Digital Sky Survey DR8 SDSS-XDQSO photometric catalog. The CMB lensing quasar cross-power spectrum is detected for the first time at a significance of 3.8 sigma, which directly confirms that the quasar distribution traces the mass distribution at high redshifts z > 1. Our detection passes a number of null tests and systematic checks. Using this cross-power spectrum, we measure the amplitude of the linear quasar bias assuming a template for its redshift dependence, and find the amplitude to be consistent with an earlier measurement from clustering; at redshift z ap 1.4, the peak of the distribution of quasars in our maps, our measurement corresponds to a bias of b = 2.5 +/- 0.6. With the signal-to-noise ratio on CMB lensing measurements likely to improve by an order of magnitude over the next few years, our results demonstrate the potential of CMB lensing crosscorrelations to probe astrophysics at high redshifts.

  19. Sunyaev-Zel'dovich Effect and X-ray Scaling Relations from Weak-Lensing Mass Calibration of 32 SPT Selected Galaxy Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Dietrich, J.P.; et al.

    2017-11-14

    Uncertainty in the mass-observable scaling relations is currently the limiting factor for galaxy cluster based cosmology. Weak gravitational lensing can provide a direct mass calibration and reduce the mass uncertainty. We present new ground-based weak lensing observations of 19 South Pole Telescope (SPT) selected clusters and combine them with previously reported space-based observations of 13 galaxy clusters to constrain the cluster mass scaling relations with the Sunyaev-Zel'dovich effect (SZE), the cluster gas mass $M_\\mathrm{gas}$, and $Y_\\mathrm{X}$, the product of $M_\\mathrm{gas}$ and X-ray temperature. We extend a previously used framework for the analysis of scaling relations and cosmological constraints obtained from SPT-selected clusters to make use of weak lensing information. We introduce a new approach to estimate the effective average redshift distribution of background galaxies and quantify a number of systematic errors affecting the weak lensing modelling. These errors include a calibration of the bias incurred by fitting a Navarro-Frenk-White profile to the reduced shear using $N$-body simulations. We blind the analysis to avoid confirmation bias. We are able to limit the systematic uncertainties to 6.4% in cluster mass (68% confidence). Our constraints on the mass-X-ray observable scaling relations parameters are consistent with those obtained by earlier studies, and our constraints for the mass-SZE scaling relation are consistent with the the simulation-based prior used in the most recent SPT-SZ cosmology analysis. We can now replace the external mass calibration priors used in previous SPT-SZ cosmology studies with a direct, internal calibration obtained on the same clusters.

  20. Dark matter halo properties of GAMA galaxy groups from 100 square degrees of KiDS weak lensing data

    NARCIS (Netherlands)

    Viola, M.; Cacciato, M.; Brouwer, M.; Kuijken, K.; Hoekstra, H.; Norberg, P.; Robotham, A. S. G.; van Uitert, E.; Alpaslan, M.; Baldry, I. K.; Choi, A.; de Jong, J. T. A.; Driver, S. P.; Erben, T.; Grado, A.; Graham, Alister W.; Heymans, C.; Hildebrandt, H.; Hopkins, A. M.; Irisarri, N.; Joachimi, B.; Loveday, J.; Miller, L.; Nakajima, R.; Schneider, P.; Sifón, C.; Verdoes Kleijn, G.

    2015-01-01

    The Kilo-Degree Survey is an optical wide-field survey designed to map the matter distribution in the Universe using weak gravitational lensing. In this paper, we use these data to measure the density profiles and masses of a sample of ˜1400 spectroscopically identified galaxy groups and clusters

  1. Kinematics, Turbulence and Star Formation of z ˜1 Strongly Lensed Galaxies seen with MUSE

    Science.gov (United States)

    Patrício, V.; Richard, J.; Carton, D.; Contini, T.; Epinat, B.; Brinchmann, J.; Schmidt, K. B.; Krajnović, D.; Bouché, N.; Weilbacher, P. M.; Pelló, R.; Caruana, J.; Maseda, M.; Finley, H.; Bauer, F. E.; Martinez, J.; Mahler, G.; Lagattuta, D.; Clément, B.; Soucail, G.; Wisotzki, L.

    2018-03-01

    We analyse a sample of 8 highly magnified galaxies at redshift 0.6 star formation rates, extinction and metallicity from multiple nebular lines, concluding that our sample is representative of z ˜1 star-forming galaxies. We derive the 2D kinematics of these galaxies from the [O II ] emission and model it with a new method that accounts for lensing effects and fits multiple images simultaneously. We use these models to calculate the 2D beam-smearing correction and derive intrinsic velocity dispersion maps. We find them to be fairly homogeneous, with relatively constant velocity dispersions between 15 - 80 km s-1and Gini coefficent of ⪉ 0.3. We do not find any evidence for higher (or lower) velocity dispersions at the positions of bright star-forming clumps. We derive resolved maps of dust attenuation and attenuation-corrected star formation rates from emission lines for two objects in the sample. We use this information to study the relation between resolved star formation rate and velocity dispersion. We find that these quantities are not correlated, and the high velocity dispersions found for relatively low star-forming densities seems to indicate that, at sub-kiloparsec scales, turbulence in high-z discs is mainly dominated by gravitational instability rather than stellar feedback.

  2. A STRONGLY LENSED MASSIVE ULTRACOMPACT QUIESCENT GALAXY AT z {approx} 2.4 IN THE COSMOS/UltraVISTA FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Muzzin, Adam; Labbe, Ivo; Franx, Marijn; Holt, J.; Szomoru, Daniel; Van de Sande, Jesse [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Van Dokkum, Pieter [Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States); Brammer, Gabriel [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago (Chile); Marchesini, Danilo [Department of Physics and Astronomy, Tufts University, Medford, MA 06520 (United States); Stefanon, Mauro [Obseratori Astronomic de la Universitat de Valencia, E-46980 Paterna, Valencia (Spain); Buitrago, F.; Dunlop, James [SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJL (United Kingdom); Caputi, K. I. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands); Fynbo, J. P. U.; Milvang-Jensen, Bo [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Le Fevre, Olivier [Laboratoire d' Astrophysique de Marseille, CNRS and Aix-Marseille Universite, 38 rue Frederic Joliot-Curie, F-13388 Marseille Cedex 13 (France); McCracken, Henry J. [Institut d' Astrophysique de Paris, UMR7095 CNRS, Universite Pierre et Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France)

    2012-12-20

    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{sub s} -bright high-redshift galaxies with red J - K{sub s} colors using new data from the UltraVISTA YJHK{sub 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{sub s} -band image, to constrain the size and Sersic profile of the galaxy. The best-fit model is an ultracompact galaxy (R{sub e} = 0.64{sup +0.08}{sub -0.18} kpc, lensing-corrected), with a Sersic profile that is intermediate between a disk and a bulge profile (n 2.2{sup +2.3}{sub -{sub 0.9}}), albeit with considerable uncertainties on the Sersic 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{sub star}/M{sub Sun }) = 10.8{sup +0.1}{sub -0.1}, lensing-corrected) with an age of 1.0{sup +1.0}{sub -0.4} Gyr, moderate dust extinction (A{sub v} = 0.8{sup +0.5}{sub -0.6}), and a low specific star formation rate (log(SSFR) <-11.0 yr{sup -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

  3. NEARBY PLANETARY SYSTEMS AS LENSES DURING PREDICTED CLOSE PASSAGES TO BACKGROUND STARS

    Energy Technology Data Exchange (ETDEWEB)

    Di Stefano, Rosanne; Matthews, James [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Lepine, Sebastien [Department of Astrophysics, Division of Physical Sciences, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States)

    2013-07-10

    The Einstein rings and proper motions of nearby stars tend to be large. Thus, every year some foreground stars within a few hundred parsecs of Earth induce gravitational lensing events in background stars. In some of these cases, the events may exhibit evidence of planets orbiting the nearby star. In fact, planets can even be discovered during relatively distant passages. Here, we study the lensing signatures associated with planets orbiting nearby high-proper-motion stars. We find the following. (1) Wide-orbit planets can be detected for all distances of closest approach between the foreground and background stars, potentially producing independent events long before and/or after the closest approach. (2) Close-orbit planets can be detected for intermediate distances of closest approach, producing quasiperiodic signatures that may occur days or weeks before and after the stellar-lens event. (3) Planets in the so-called zone for resonant lensing can significantly increase the magnification when the distance of closest approach is small, making the stellar-lens event easier to detect, while simultaneously providing evidence for planets. Because approaches close enough to allow planets to be detected can be predicted, we can plan observing strategies to take advantage of the theoretical framework built in this paper, which describes the sequence of expected effects in terms of a sequence of detection regimes.

  4. Detection of the power spectrum of cosmic microwave background lensing by the Atacama Cosmology Telescope.

    Science.gov (United States)

    Das, Sudeep; Sherwin, Blake D; Aguirre, Paula; Appel, John W; Bond, J Richard; Carvalho, C Sofia; Devlin, Mark J; Dunkley, Joanna; Dünner, Rolando; Essinger-Hileman, Thomas; Fowler, Joseph W; Hajian, Amir; Halpern, Mark; Hasselfield, Matthew; Hincks, Adam D; Hlozek, Renée; Huffenberger, Kevin M; Hughes, John P; Irwin, Kent D; Klein, Jeff; Kosowsky, Arthur; Lupton, Robert H; Marriage, Tobias A; Marsden, Danica; Menanteau, Felipe; Moodley, Kavilan; Niemack, Michael D; Nolta, Michael R; Page, Lyman A; Parker, Lucas; Reese, Erik D; Schmitt, Benjamin L; Sehgal, Neelima; Sievers, Jon; Spergel, David N; Staggs, Suzanne T; Swetz, Daniel S; Switzer, Eric R; Thornton, Robert; Visnjic, Katerina; Wollack, Ed

    2011-07-08

    We report the first detection of the gravitational lensing of the cosmic microwave background through a measurement of the four-point correlation function in the temperature maps made by the Atacama Cosmology Telescope. We verify our detection by calculating the levels of potential contaminants and performing a number of null tests. The resulting convergence power spectrum at 2° angular scales measures the amplitude of matter density fluctuations on comoving length scales of around 100 Mpc at redshifts around 0.5 to 3. The measured amplitude of the signal agrees with Lambda cold dark matter cosmology predictions. Since the amplitude of the convergence power spectrum scales as the square of the amplitude of the density fluctuations, the 4σ detection of the lensing signal measures the amplitude of density fluctuations to 12%.

  5. A Study of Galaxies and Quasars in the Background of the Andromeda Galaxy

    Science.gov (United States)

    Dhara, Atirath; McConnell, Kaela; Guhathakurta, Puragra; Roy, Namrata; Waite, Jurij

    2018-01-01

    The SPLASH (Spectroscopic and Photometric Landscape of Andromeda’s Stellar Halo) survey is based on wide-field ground-based optical images (KPNO 4-m/Mosaic, CFHT 3.6-m/MegaCam imager, and Subaru 8-m/Suprime-Cam), deep Hubble Space Telescope ultraviolet/optical/near infrared images (ACS and WFC3), and medium resolution spectra (Keck II 10-m/DEIMOS). The SPLASH survey data set contains two main categories of (non-M31) contaminants (SPLASH trash, if you will): foreground Milky Way stars and compact background galaxies/quasars. In this poster, we present the discovery and characterization of galaxies and quasars behind M31. Such objects were identified based on the presence of redshifted emission lines and other galaxy/quasar spectral features (e.g., Ca H+K absorption and IGM absorption). The redshift of each galaxy was measured by cross-correlating its spectrum against an emission line galaxy spectral template. The cross-correlation results (spectrum and best-fit template) were visually inspected to identify cases of incorrect matching of emission lines. Many of these incorrect redshift estimates were corrected by using the second or third highest cross-correlation peak. Quasar redshifts were determined based on cross-correlation against a quasar spectral template. Most of the galaxies in our sample are star forming galaxies with strong emission lines. We analyze their emission line flux ratios in a BPT diagram to learn more about the ionization source and metallicity. Finally, the properties of these compact galaxies behind M31 are compared to those of galaxies selected in a more standard way in the DEEP2 redshift survey to explore the effects of morphological pre-selection (compact vs. extended) on the properties of the resulting galaxy sample.This research was supported by NASA/STScI and the National Science Foundation. Most of this work was carried out by high school students working under the auspices of the Science Internship Program (SIP) at UC Santa Cruz.

  6. A magnified view of star formation at z = 0.9 from two lensed galaxies

    International Nuclear Information System (INIS)

    Olmstead, Alice; Veilleux, Sylvain; Rigby, Jane R.; Swinbank, Mark

    2014-01-01

    We present new narrowband Hα imaging from the Hubble Space Telescope of two z = 0.91 galaxies that have been lensed by the foreground galaxy cluster A2390. These data probe spatial scales as small as ∼0.3 kpc, providing a magnified look at the morphology of star formation at an epoch when the global star formation rate (SFR) was high. However, dust attenuates our spatially resolved SFR indicators, the Hα and rest-UV emission, and we lack a direct measurement of extinction. Other studies have found that ionized gas in galaxies tends to be roughly 50% more obscured than stars; however, given an unextincted measurement of the SFR we can quantify the relative stellar to nebular extinction and the extinction in Hα. We infer SFRs from Spitzer and Herschel mid- to far-infrared observations and compare these to integrated Hα and rest-UV SFRs; this yields stellar to nebular extinction ratios consistent with previous studies. We take advantage of high spatial resolution and contextualize these results in terms of the source-plane morphologies, comparing the distribution of Hα to that of the rest-frame UV and optical light. In one galaxy, we measure separate SFRs in visually distinct clumps, but can set only a lower limit on the extinction and thus the star formation. Consequently, the data are also consistent with there being an equal amount of extinction along the lines of sight to the ionized gas as to the stars. Future observations in the far-infrared could settle this by mapping out the dust directly.

  7. Constraining cosmic curvature by using age of galaxies and gravitational lenses

    International Nuclear Information System (INIS)

    Rana, Akshay; Mahajan, Shobhit; Mukherjee, Amitabha; Jain, Deepak

    2017-01-01

    We use two model-independent methods to constrain the curvature of the universe. In the first method, we study the evolution of the curvature parameter (Ω k 0 ) with redshift by using the observations of the Hubble parameter and transverse comoving distances obtained from the age of galaxies. Secondly, we also use an indirect method based on the mean image separation statistics of gravitationally lensed quasars. The basis of this methodology is that the average image separation of lensed images will show a positive, negative or zero correlation with the source redshift in a closed, open or flat universe respectively. In order to smoothen the datasets used in both the methods, we use a non-parametric method namely, Gaussian Process (GP). Finally from first method we obtain Ω k 0 = 0.025±0.57 for a presumed flat universe while the cosmic curvature remains constant throughout the redshift region 0 < z < 1.37 which indicates that the universe may be homogeneous. Moreover, the combined result from both the methods suggests that the universe is marginally closed. However, a flat universe can be incorporated at 3σ level.

  8. Angular ellipticity correlations in a composite alignment model for elliptical and spiral galaxies and inference from weak lensing

    Science.gov (United States)

    Tugendhat, Tim M.; Schäfer, Björn Malte

    2018-02-01

    We investigate a physical, composite alignment model for both spiral and elliptical galaxies and its impact on cosmological parameter estimation from weak lensing for a tomographic survey. Ellipticity correlation functions and angular ellipticity spectra for spiral and elliptical galaxies are derived on the basis of tidal interactions with the cosmic large-scale structure and compared to the tomographic weak lensing signal. We find that elliptical galaxies cause a contribution to the weak-lensing dominated ellipticity correlation on intermediate angular scales between ℓ ≃ 40 and ℓ ≃ 400 before that of spiral galaxies dominates on higher multipoles. The predominant term on intermediate scales is the negative cross-correlation between intrinsic alignments and weak gravitational lensing (GI-alignment). We simulate parameter inference from weak gravitational lensing with intrinsic alignments unaccounted; the bias induced by ignoring intrinsic alignments in a survey like Euclid is shown to be several times larger than the statistical error and can lead to faulty conclusions when comparing to other observations. The biases generally point into different directions in parameter space, such that in some cases one can observe a partial cancellation effect. Furthermore, it is shown that the biases increase with the number of tomographic bins used for the parameter estimation process. We quantify this parameter estimation bias in units of the statistical error and compute the loss of Bayesian evidence for a model due to the presence of systematic errors as well as the Kullback-Leibler divergence to quantify the distance between the true model and the wrongly inferred one.

  9. Angular ellipticity correlations in a composite alignment model for elliptical and spiral galaxies and inference from weak lensing

    Science.gov (United States)

    Tugendhat, Tim M.; Schäfer, Björn Malte

    2018-05-01

    We investigate a physical, composite alignment model for both spiral and elliptical galaxies and its impact on cosmological parameter estimation from weak lensing for a tomographic survey. Ellipticity correlation functions and angular ellipticity spectra for spiral and elliptical galaxies are derived on the basis of tidal interactions with the cosmic large-scale structure and compared to the tomographic weak-lensing signal. We find that elliptical galaxies cause a contribution to the weak-lensing dominated ellipticity correlation on intermediate angular scales between ℓ ≃ 40 and ℓ ≃ 400 before that of spiral galaxies dominates on higher multipoles. The predominant term on intermediate scales is the negative cross-correlation between intrinsic alignments and weak gravitational lensing (GI-alignment). We simulate parameter inference from weak gravitational lensing with intrinsic alignments unaccounted; the bias induced by ignoring intrinsic alignments in a survey like Euclid is shown to be several times larger than the statistical error and can lead to faulty conclusions when comparing to other observations. The biases generally point into different directions in parameter space, such that in some cases one can observe a partial cancellation effect. Furthermore, it is shown that the biases increase with the number of tomographic bins used for the parameter estimation process. We quantify this parameter estimation bias in units of the statistical error and compute the loss of Bayesian evidence for a model due to the presence of systematic errors as well as the Kullback-Leibler divergence to quantify the distance between the true model and the wrongly inferred one.

  10. GRAVITATIONAL IMAGING BY ELLIPTIC GALAXIES - THE EFFECTS OF DARK HALOS

    NARCIS (Netherlands)

    BREIMER, TG; SANDERS, RH

    It has been claimed that some gravitational lenses in which a background quasar is multiply-imaged by a single foreground galaxy support the existence of dark massive halos in elliptical galaxies. We reexamine this claim by considering the lensing effects of spherical galaxies with and without a

  11. Galaxy-galaxy lensing in EAGLE: comparison with data from 180 deg2 of the KiDS and GAMA surveys

    Science.gov (United States)

    Velliscig, Marco; Cacciato, Marcello; Hoekstra, Henk; Schaye, Joop; Heymans, Catherine; Hildebrandt, Hendrik; Loveday, Jon; Norberg, Peder; Sifón, Cristóbal; Schneider, Peter; van Uitert, Edo; Viola, Massimo; Brough, Sarah; Erben, Thomas; Holwerda, Benne W.; Hopkins, Andrew M.; Kuijken, Konrad

    2017-11-01

    We present predictions for the galaxy-galaxy lensing (GGL) profile from the EAGLE hydrodynamical cosmological simulation at redshift z = 0.18, in the spatial range 0.02 EAGLE predictions are in broad agreement with the observed profiles for both central and satellite galaxies, although the signal is underestimated at R ≈ 0.5-2 h- 1 Mpc for the highest stellar mass bins. When central and satellite galaxies are considered simultaneously, agreement is found only when the selection function of lens galaxies is taken into account in detail. Specifically, in the case of GAMA galaxies, it is crucial to account for the variation of the fraction of satellite galaxies in bins of stellar mass induced by the flux-limited nature of the survey. We report the inferred stellar-to-halo mass relation and we find good agreement with recent published results. We note how the precision of the GGL profiles in the simulation holds the potential to constrain fine-grained aspects of the galaxy-dark matter connection.

  12. THE SLOAN DIGITAL SKY SURVEY CO-ADD: CROSS-CORRELATION WEAK LENSING AND TOMOGRAPHY OF GALAXY CLUSTERS

    International Nuclear Information System (INIS)

    Simet, Melanie; Dodelson, Scott; Kubo, Jeffrey M.; Annis, James T.; Hao Jiangang; Johnston, David; Lin, Huan; Soares-Santos, Marcelle; Reis, Ribamar R. R.; Seo, Hee-Jong

    2012-01-01

    The shapes of distant galaxies are sheared by intervening galaxy clusters. We examine this effect in Stripe 82, a 275 deg 2 region observed multiple times in the Sloan Digital Sky Survey (SDSS) and co-added to achieve greater depth. We obtain a mass-richness calibration that is similar to other SDSS analyses, demonstrating that the co-addition process did not adversely affect the lensing signal. We also propose a new parameterization of the effect of tomography on the cluster lensing signal which does not require binning in redshift, and we show that using this parameterization we can detect tomography for stacked clusters at varying redshifts. Finally, due to the sensitivity of the tomographic detection to accurately marginalize over the effect of the cluster mass, we show that tomography at low redshift (where dependence on exact cosmological models is weak) can be used to constrain mass profiles in clusters.

  13. Precise weak lensing constraints from deep high-resolution Ks images: VLT/HAWK-I analysis of the super-massive galaxy cluster RCS2 J 232727.7-020437 at z = 0.70

    Science.gov (United States)

    Schrabback, Tim; Schirmer, Mischa; van der Burg, Remco F. J.; Hoekstra, Henk; Buddendiek, Axel; Applegate, Douglas; Bradač, Maruša; Eifler, Tim; Erben, Thomas; Gladders, Michael D.; Hernández-Martín, Beatriz; Hildebrandt, Hendrik; Hoag, Austin; Klaes, Dominik; von der Linden, Anja; Marchesini, Danilo; Muzzin, Adam; Sharon, Keren; Stefanon, Mauro

    2018-03-01

    We demonstrate that deep good-seeing VLT/HAWK-I Ks images complemented with g + z-band photometry can yield a sensitivity for weak lensing studies of massive galaxy clusters at redshifts 0.7 ≲ z ≲ 1.1, which is almost identical to the sensitivity of HST/ACS mosaics of single-orbit depth. Key reasons for this good performance are the excellent image quality frequently achievable for Ks imaging from the ground, a highly effective photometric selection of background galaxies, and a galaxy ellipticity dispersion that is noticeably lower than for optically observed high-redshift galaxy samples. Incorporating results from the 3D-HST and UltraVISTA surveys we also obtained a more accurate calibration of the source redshift distribution than previously achieved for similar optical weak lensing data sets. Here we studied the extremely massive galaxy cluster RCS2 J232727.7-020437 (z = 0.699), combining deep VLT/HAWK-I Ks images (point spread function with a 0.''35 full width at half maximum) with LBT/LBC photometry. The resulting weak lensing mass reconstruction suggests that the cluster consists of a single overdensity, which is detected with a peak significance of 10.1σ. We constrained the cluster mass to M200c/(1015 M⊙) = 2.06-0.26+0.28(stat.) ± 0.12(sys.) assuming a spherical Navarro, Frenk & White model and simulation-based priors on the concentration, making it one of the most massive galaxy clusters known in the z ≳ 0.7 Universe. We also cross-checked the HAWK-I measurements through an analysis of overlapping HST/ACS images, yielding fully consistent estimates of the lensing signal. Based on observations conducted with the ESO Very Large Telescope, the Large Binocular Telescope, and the NASA/ESA Hubble Space Telescope, as detailed in the acknowledgements.

  14. Effects of Galaxy collisions on the structure and evolution of Galaxy clusters. I. Mass and luminosity functions and background light

    International Nuclear Information System (INIS)

    Miller, G.E.; Department of Astronomy, University of Texas at Austin)

    1983-01-01

    The role of galaxy collisions in controlling the form of the galaxy mass and luminosity functions and in creating a diffuse background light is investigated by means of a direct computer simulation. Galaxy collisions are treated in a realistic manner, including both galaxy mergers and tidal encounters. A large number of theoretical studies of a galaxy collisions were consulted to formulate the basic input physics of collision cross sections. Despite this large number of studies, there remains considerable uncertainty in the effects of a collision on a galaxy due mainly to our lack of knowledge of the orbital distribution of matter in galaxies. To improve this situation, some methods of semiempirical calibration are suggested: for example, a survey of background light in clusters of different richness and morphological classes. If real galaxies are represented by galaxy models where the bulk of the matter is on radial, rather than circular, orbits, then tidal collisions are more damaging and there are a number of interesting effects: Repeated tidal encounters lead to galaxy mass and luminosity functions which are largely independent of model parameters and the initial galaxy mass function. It appears unlikely that the form of the average present-day luminosity function characteristic of both field and cluster galaxies is due to collisions, but certain observed deviations from the average found by Heiligman and Turner and by Dressler may be a signature of collisions, in particular a flat faint-end slope. The amount of luminous matter stripped from the galaxies in the simulations agrees with the amount of diffuse background light seen in the Coma Cluster

  15. Submillimeter H2O and H2O+emission in lensed ultra- and hyper-luminous infrared galaxies at z 2-4

    NARCIS (Netherlands)

    Yang, C.; Omont, A.; Beelen, A.; González-Alfonso, E.; Neri, R.; Gao, Y.; van der Werf, P.; Weiß, A.; Gavazzi, R.; Falstad, N.; Baker, A. J.; Bussmann, R. S.; Cooray, A.; Cox, P.; Dannerbauer, H.; Dye, S.; Guélin, M.; Ivison, R.; Krips, M.; Lehnert, M.; Michałowski, M. J.; Riechers, D. A.; Spaans, M.; Valiante, E.

    2016-01-01

    We report rest-frame submillimeter H2O emission line observations of 11 ultra- or hyper-luminous infrared galaxies (ULIRGs or HyLIRGs) at z 2-4 selected among the brightest lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). Using the IRAM NOrthern

  16. 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.

  17. Planck intermediate results XXVII. High-redshift infrared galaxy overdensity candidates and lensed sources discovered by Planck and confirmed by Herschel-SPIRE⋆

    DEFF Research Database (Denmark)

    Aghanim, N.; Altieri, B.; Arnaud, M.

    2015-01-01

    with high significance, half of the sample showing statistical significance above 10 sigma. The SPIRE photometric redshifts of galaxies in overdensities suggest a peak at z similar or equal to 2, assuming a single common dust temperature for the sources of T-d = 35 K. Under this assumption, we derive......) directly from the maps and from the Planck Catalogue of Compact Sources (PCCS), all satisfy the criterion of having their rest-frame far-infrared peak redshifted to the frequency range 353-857 GHz. This colour-selection favours galaxies in the redshift range z = 2-4, which we consider as cold peaks...... in the cosmic infrared background. With a 4.'5 beam at the four highest frequencies, our sample is expected to include overdensities of galaxies in groups or clusters, lensed galaxies, and chance line-of-sight projections. We perform a dedicated Herschel-SPIRE follow-up of 234 such Planck targets, finding...

  18. Angular spectra of the intrinsic galaxy ellipticity field, their observability and their impact on lensing in tomographic surveys

    Science.gov (United States)

    Schäfer, Björn Malte; Merkel, Philipp M.

    2017-09-01

    This paper describes intrinsic ellipticity correlations between galaxies, their statistical properties, their observability with future surveys and their interference with weak gravitational lensing measurements. Using an angular-momentum-based, quadratic intrinsic alignment model we derive correlation functions of the ellipticity components and project them to yield the four non-zero angular ellipticity spectra C^ɛ _E(ℓ), C^ɛ _B(ℓ), C^ɛ _C(ℓ) and C^ɛ _S(ℓ) in their generalization to tomographic surveys. For a Euclid-like survey, these spectra would have amplitudes smaller than the weak lensing effect on non-linear structures, but would constitute an important systematics. Computing estimation biases for cosmological parameters derived from an alignment-contaminated survey suggests biases of +5σw for the dark energy equation of state parameter w, -20σ _{Ω _m} for the matter density Ωm and -12σ _{σ _8} for the spectrum normalization σ8. Intrinsic alignments yield a signal that is easily observable with a survey similar to Euclid: while not independent, significances for estimates of each of the four spectra reach values of tens of σ if weak lensing and shape noise are considered as noise sources, which suggests relative uncertainties on alignment parameters at the percent level, implying that galaxy alignment mechanisms can be investigated by future surveys.

  19. Strong Lensing Science Results from the Hyper Suprime-Cam Survey

    Science.gov (United States)

    Wong, Kenneth; HSC SSP Strong Lens Working Group

    2018-01-01

    Strong gravitational lenses are valuable objects for studying galaxy structure and cosmology. Lensing is a unique probe of the dark matter structure of galaxies, groups, and clusters, as well as an independent tool for constraining cosmological parameters. Lensing also magnifies the background source population, allowing for detailed studies of their properties at high resolution. However, strong lenses are rare and difficult to find, requiring deep wide-area high-resolution imaging surveys. With data from the ongoing Hyper Suprime-Cam (HSC) Subaru Strategic Program, we have discovered over 100 new strong lenses at the galaxy and group scale to expand the sample of lensing systems, particularly at redshifts z > 0.5, where there have previously been relatively few known lenses. We present a summary of the latest strong lensing science results from the HSC survey data taken through the S17A semester.

  20. VizieR Online Data Catalog: Spectroscopy of strong lensing galaxy clusters (Carrasco+, 2017)

    Science.gov (United States)

    Carrasco, M.; Barrientos, L. F.; Anguita, T.; Garcia-Vergara, C.; Bayliss, M.; Gladders, M.; Gilbank, D.; Yee, H. K. C.; West, M.

    2017-07-01

    The cluster sample presented here is a subset of a larger sample of more than one hundred strong lensing (SL)-selected clusters that have been identified primarily in Second Red-Sequence Cluster Survey (RCS-2; Gilbank+ 2011AJ....141...94G) imaging data. The median seeing of the RCS-2 survey is ~0.7". We supplement the RCS-2 SL-selected cluster sample with a few systems chosen to fill R.A. gaps that were similarly selected from the Sloan Digital Sky Survey (SDSS, see II/294). We performed a comprehensive spectroscopic follow-up of 29 SL-selected galaxy clusters primarily from the Red-Sequence Cluster Survey Giant Arc (RCSGA; Bayliss 2012ApJ...744..156B; M. D. Gladders et al. 2016, in preparation); 7 of these clusters were previously unpublished. The cluster sample is presented in Table 1. Most of the imaging data presented here have been obtained from the RCS-2 survey. They were collected in queue-scheduled mode with MegaCam at the 3.6m Canada-France-Hawaii Telescope (CFHT), between the semesters 2003A and 2007B inclusive. We have also obtained pre-imaging of our clusters in B, R, and I bands, with the Focal Reducer and low dispersion Spectrograph 2 (FORS2) at the ESO 8.2m Very Large Telescope (VLT), in queue mode. The FORS2/VLT observations were carried out between 2006 October and 2010 March using the Multi-object spectroscopy. We have also performed spectroscopic observations with the Inamori Magellan Areal Camera and Spectrograph (IMACS) on the 6.5m Magellan (Baade) telescope at LCO. The IMACS/Magellan observations were collected during six different runs between 2008 June and 2011 March. (4 data files).

  1. THE SEARCH FOR Hi EMISSION AT z ≈ 0.4 IN GRAVITATIONALLY LENSED GALAXIES WITH THE GREEN BANK TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, L. R.; Pisano, D. J. [Department of Physics and Astronomy, West Virginia University, P.O. Box 6315, Morgantown, WV 26506 (United States); Edel, S., E-mail: lhunt3@mix.wvu.edu, E-mail: djpisano@mail.wvu.edu, E-mail: stasedel@gmail.com [Infinite Optics, 1712 Newport Cir # F, Santa Ana, CA 92705 (United States)

    2016-08-01

    Neutral hydrogen (Hi) provides a very important fuel for star formation, but is difficult to detect at high redshift due to weak emission, limited sensitivity of modern instruments, and terrestrial radio frequency interference (RFI) at low frequencies. We report the first attempt to use gravitational lensing to detect Hi line emission from three gravitationally lensed galaxies behind the cluster Abell 773, two at redshifts of 0.398 and one at z = 0.487, using the Green Bank Telescope. We find that a 3 σ upper limit for a galaxy with a rotation velocity of 200 km s{sup −1} is M{sub Hi} = 6.58 × 10{sup 9} and 1.5 × 10{sup 10} M {sub ⊙} at z = 0.398 and z = 0.487. The estimated Hi masses of the sources at z = 0.398 and z = 0.487 are factors of 3.7 and ∼30 times lower than our detection limits at the respective redshifts. To facilitate these observations we have used sigma-clipping to remove both narrow- and wideband RFI but retain the signal from the source. We are able to reduce the noise of the spectrum by ∼25% using our routine instead of discarding observations with too much RFI. The routine is most effective when ∼10% of the integrations or fewer contain RFI. These techniques can be used to study Hi in highly magnified distant galaxies that are otherwise too faint to detect.

  2. Full-sky Ray-tracing Simulation of Weak Lensing Using ELUCID Simulations: Exploring Galaxy Intrinsic Alignment and Cosmic Shear Correlations

    Science.gov (United States)

    Wei, Chengliang; Li, Guoliang; Kang, Xi; Luo, Yu; Xia, Qianli; Wang, Peng; Yang, Xiaohu; Wang, Huiyuan; Jing, Yipeng; Mo, Houjun; Lin, Weipeng; Wang, Yang; Li, Shijie; Lu, Yi; Zhang, Youcai; Lim, S. H.; Tweed, Dylan; Cui, Weiguang

    2018-01-01

    The intrinsic alignment of galaxies is an important systematic effect in weak-lensing surveys, which can affect the derived cosmological parameters. One direct way to distinguish different alignment models and quantify their effects on the measurement is to produce mock weak-lensing surveys. In this work, we use the full-sky ray-tracing technique to produce mock images of galaxies from the ELUCID N-body simulation run with WMAP9 cosmology. In our model, we assume that the shape of the central elliptical galaxy follows that of the dark matter halo, and that of the spiral galaxy follows the halo spin. Using the mock galaxy images, a combination of galaxy intrinsic shape and the gravitational shear, we compare the predicted tomographic shear correlations to the results of the Kilo-Degree Survey (KiDS) and Deep Lens Survey (DLS). We find that our predictions stay between the KiDS and DLS results. We rule out a model in which the satellite galaxies are radially aligned with the center galaxy; otherwise, the shear correlations on small scales are too high. Most importantly, we find that although the intrinsic alignment of spiral galaxies is very weak, they induce a positive correlation between the gravitational shear signal and the intrinsic galaxy orientation (GI). This is because the spiral galaxy is tangentially aligned with the nearby large-scale overdensity, contrary to the radial alignment of the elliptical galaxy. Our results explain the origin of the detected positive GI term in the weak-lensing surveys. We conclude that in future analyses, the GI model must include the dependence on galaxy types in more detail.

  3. Dusty Dwarfs Galaxies Occulting A Bright Background Spiral

    Science.gov (United States)

    Holwerda, Benne

    2017-08-01

    The role of dust in shaping the spectral energy distributions of low mass disk galaxies remains poorly understood. Recent results from the Herschel Space Observatory imply that dwarf galaxies contain large amounts of cool (T 20K) dust, coupled with very modest optical extinctions. These seemingly contradictory conclusions may be resolved if dwarfs harbor a variety of dust geometries, e.g., dust at larger galactocentric radii or in quiescent dark clumps. We propose HST observations of six truly occulting dwarf galaxies drawn from the Galaxy Zoo catalog of silhouetted galaxy pairs. Confirmed, true occulting dwarfs are rare as most low-mass disks in overlap are either close satellites or do not have a confirmed redshift. Dwarf occulters are the key to determining the spatial extent of dust, the small scale structure introduced by turbulence, and the prevailing dust attenuation law. The recent spectroscopic confirmation of bona-fide low mass occulting dwarfs offers an opportunity to map dust in these with HST. What is the role of dust in the SED of these dwarf disk galaxies? With shorter feedback scales, how does star-formation affect their morphology and dust composition, as revealed from their attenuation curve? The resolution of HST allows us to map the dust disks down to the fine scale structure of molecular clouds and multi-wavelength imaging maps the attenuation curve and hence dust composition in these disks. We therefore ask for 2 orbits on each of 6 dwarf galaxies in F275W, F475W, F606W, F814W and F125W to map dust from UV to NIR to constrain the attenuation curve.

  4. Constraints on Dark Energy Models from Galaxy Clusters and Gravitational Lensing Data

    Directory of Open Access Journals (Sweden)

    Alexander Bonilla

    2018-01-01

    Full Text Available The Sunyaev–Zel’dovich (SZ effect is a global distortion of the Cosmic Microwave Background (CMB spectrum as a result of its interaction with a hot electron plasma in the intracluster medium of large structures gravitationally viralized such as galaxy clusters (GC. Furthermore, this hot gas of electrons emits X-rays due to its fall in the gravitational potential well of the GC. The analysis of SZ and X-ray data provides a method for calculating distances to GC at high redshifts. On the other hand, many galaxies and GC produce a Strong Gravitational Lens (SGL effect, which has become a useful astrophysical tool for cosmology. We use these cosmological tests in addition to more traditional ones to constrain some alternative dark energy (DE models, including the study of the history of cosmological expansion through the cosmographic parameters. Using Akaike and Bayesian Information Criterion, we find that the w C D M and Λ C D M models are the most favoured by the observational data. In addition, we found at low redshift a peculiar behavior of slowdown of the universe, which occurs in dynamical DE models when we use data from GC.

  5. Lensing reconstruction of cluster-mass cross correlation with cosmic microwave background polarization

    International Nuclear Information System (INIS)

    Yoo, Jaiyul; Hernquist, Lars; Zaldarriaga, Matias

    2010-01-01

    We extend our maximum likelihood method for reconstructing the cluster-mass cross correlation from cosmic microwave background (CMB) temperature anisotropies and develop new estimators that utilize six different quadratic combinations of CMB temperature and polarization fields. Our maximum likelihood estimators are constructed with delensed CMB temperature and polarization fields by using an assumed model of the convergence field, and they can be iteratively applied to a set of clusters, approaching the optimal condition for the lensing reconstruction as the assumed initial model is refined. Using smoothed particle hydrodynamics simulations, we create a catalog of realistic clusters obtainable from the current Sunyaev-Zel'dovich surveys, and we demonstrate the ability of the maximum likelihood estimators to reconstruct the cluster-mass cross correlation from the massive clusters. The iTT temperature estimator provides a signal-to-noise ratio of a factor of 3 larger than the iEB polarization estimator, unless the detector noise for measuring polarization anisotropies is controlled under 3 μK.

  6. Revealing the ISM in high redshift starburst galaxies: An analysis of Herschel PACS and SPIRE FTS spectroscopic observations of HerMES and H-ATLAS-selected lensed galaxies

    Science.gov (United States)

    Cooray, Asantha

    In the quest to develop a fundamental understanding of galaxy formation and evolution, observations of dusty star-forming galaxies (DSFGs) promise significant progress this decade. The importance of DSFGs is highlighted by the fact that half of the energy emitted by extragalactic sources emerges as dust-reprocessed light at infrared (IR) to sub millimeter wavelength. In the post-herschel\\ era, we are now at a unique position to tackle some of the key questions on galaxy formation and evolution because of the large area Herschel's Key Project surveys (HerMES and H-ATLAS). In particular those surveys have allowed us to identify a sample of 250 strongly gravitationally lensed DSFGs at z > 1. They give us a unique opportunity to dissect the detailed structures and kinematics of DSFGs. The Herschel Science Archive also contains individual follow up data on 44 and 25 of the brightest sources with SPIRE-FTS and PACS, respectively, in the spectroscopy mode, taking over 250 hours in four open-time programs. Only one of the 44 SPIRE FTS targets has yet to appear in the published literature. One of the four include an open-time 2 PACS spectroscopy program that was led at UCI by a former postdoc from the PI's group. That program was initially approved at Priority 2 in 2011, but was triggered in late 2012 and achieved 100% completion during the last two weeks of Herschel lifetime in May 2013. This archival analysis, interpretation, and modeling program involves two parts: (i) PACS spectroscopy in 50 to 200 microns of 25 lensed galaxies in the fine-structure emission lines [SiII]34, [SIII]33, [OIV]26, [OIII]52, [NIII]57 and [OI]63, and the molecular hydrogen H_2 S(0) and S(1). (ii) SPIRE FTS spectroscopy of 44 lensed galaxies, including above 25, over the wavelength range of 200 to 600 microns targeting [CII]158, [OIII]88, [OI]63/145, and [NI]122. The analysis will lead to a better understanding of the ISM of starbursting galaxies that span 1 research supports Goal 2 of the

  7. Doppler term in the galaxy two-point correlation function: Wide-angle, velocity, Doppler lensing and cosmic acceleration effects

    Science.gov (United States)

    Raccanelli, Alvise; Bertacca, Daniele; Jeong, Donghui; Neyrinck, Mark C.; Szalay, Alexander S.

    2018-03-01

    We study the parity-odd part (that we shall call Doppler term) of the linear galaxy two-point correlation function that arises from wide-angle, velocity, Doppler lensing and cosmic acceleration effects. As it is important at low redshift and at large angular separations, the Doppler term is usually neglected in the current generation of galaxy surveys. For future wide-angle galaxy surveys, however, we show that the Doppler term must be included. The effect of these terms is dominated by the magnification due to relativistic aberration effects and the slope of the galaxy redshift distribution and it generally mimics the effect of the local type primordial non-Gaussianity with the effective nonlinearity parameter fNLeff of a few; we show that this would affect forecasts on measurements of fNL at low-redshift. Our results show that a survey at low redshift with large number density over a wide area of the sky could detect the Doppler term with a signal-to-noise ratio of ∼ 1 - 20, depending on survey specifications.

  8. A direct gravitational lensing test for 10 exp 6 solar masses black holes in halos of galaxies

    Science.gov (United States)

    Wambsganss, Joachim; Paczynski, Bohdan

    1992-01-01

    We propose a method that will be able to detect or exclude the existence of 10 exp 6 solar masses black holes in the halos of galaxies. VLBA radio maps of two milliarcsecond jets of a gravitationally lensed quasar will show the signature of these black holes - if they exist. If there are no compact objects in this mass range along the line of sight, the two jets should be linear mappings of each other. If they are not, there must be compact objects of about 10 exp 6 solar masses in the halo of the galaxy that deform the images by gravitational deflection. We present numerical simulations for the two jets A and B of the double quasar 0957 + 561, but the method is valid for any gravitationally lensed quasar with structure on milliarcsecond scales. As a by-product from high-quality VLBA maps of jets A and B, one will be able to tell which features in the maps are intrinsic in the original jet and which are only an optical illusion, i.e., gravitational distortions by black holes along the line of sight.

  9. The Hawaii SCUBA-2 Lensing Cluster Survey: Are Low-luminosity Submillimeter Galaxies Detected in the Rest-frame UV?

    Science.gov (United States)

    Hsu, Li-Yen; Cowie, Lennox L.; Barger, Amy J.; Wang, Wei-Hao

    2017-12-01

    In this third paper of the Hawaii SCUBA-2 Lensing Cluster Survey series, we present Submillimeter Array (SMA) detections of six intrinsically faint 850 μm sources detected in SCUBA-2 images of the lensing cluster fields, A1689, A2390, A370, MACS J0717.5+3745, and MACS J1423.8+2404. Two of the SCUBA-2 sources split into doublets, yielding a total of eight SMA detections. The intrinsic 870 μm flux densities of these submillimeter galaxies (SMGs) are ∼1 mJy. Five of the eight SMGs are not detected in optical or near-infrared (NIR) images. The NIR-to-submillimeter flux ratios of these faint SMGs suggest that most of them are extremely dusty and/or are at very high redshifts. By combining these SMGs and several other samples from the literature, we find a bimodal distribution for the faint sources in the space of submillimeter flux versus NIR-to-submillimeter flux ratio. While most of the SMA-detected lensed sources are very obscured, the other SMGs with similar flux densities are mostly bright in the NIR. Future Atacama Large Millimeter/submillimeter Array observations of a large sample of SCUBA-2 sources in cluster fields will allow us to decide whether or not the bimodality we observe here really exists.

  10. A MEASUREMENT OF THE COSMIC MICROWAVE BACKGROUND GRAVITATIONAL LENSING POTENTIAL FROM 100 SQUARE DEGREES OF SPTPOL DATA

    Energy Technology Data Exchange (ETDEWEB)

    Story, K. T.; Hanson, D.; Ade, P. A. R.; Aird, K. A.; Austermann, J. E.; J. A. Beall,; Bender, A. N.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Chiang, H. C.; Cho, H-M.; Citron, R.; Crawford, T. M.; Crites, A. T.; Haan, T. de; Dobbs, M. A.; Everett, W.; Gallicchio, J.; Gao, J.; George, E. M.; Gilbert, A.; Halverson, N. W.; Harrington, N.; Henning, J. W.; Hilton, G. C.; Holder, G. P.; Holzapfel, W. L.; Hoover, S.; Hou, Z.; Hrubes, J. D.; Huang, N.; Hubmayr, J.; Irwin, K. D.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Li, D.; Liang, C.; Luong-Van, D.; McMahon, J. J.; Mehl, J.; Meyer, S. S.; Mocanu, L.; Montroy, T. E.; Natoli, T.; Nibarger, J. P.; Novosad, V.; Padin, S.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Schaffer, K. K.; Smecher, G.; Stark, A. A.; Tucker, C.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Yefremenko, V.; Zahn, O.

    2015-08-28

    We present a measurement of the cosmic microwave background (CMB) gravitational lensing potential using data from the first two seasons of observations with SPTpol, the polarization-sensitive receiver currently installed on the South Pole Telescope. The observations used in this work cover 100 deg(2) of sky with arcminute resolution at 150 GHz. Using a quadratic estimator, we make maps of the CMB lensing potential from combinations of CMB temperature and polarization maps. We combine these lensing potential maps to form a minimum-variance (MV) map. The lensing potential is measured with a signal-to-noise ratio of greater than one for angular multipoles between $100\\lt L\\lt 250$. This is the highest signal-to-noise mass map made from the CMB to date and will be powerful in cross-correlation with other tracers of large-scale structure. We calculate the power spectrum of the lensing potential for each estimator, and we report the value of the MV power spectrum between $100\\lt L\\lt 2000$ as our primary result. We constrain the ratio of the spectrum to a fiducial ΛCDM model to be A(MV) = 0.92 ± 0.14 (Stat.) ± 0.08 (Sys.). Restricting ourselves to polarized data only, we find A(POL) = 0.92 ± 0.24 (Stat.) ± 0.11 (Sys.). This measurement rejects the hypothesis of no lensing at $5.9\\sigma $ using polarization data alone, and at $14\\sigma $ using both temperature and polarization data.

  11. Redshift distributions of galaxies in the Dark Energy Survey Science Verification shear catalogue and implications for weak lensing

    Energy Technology Data Exchange (ETDEWEB)

    Bonnett, C.; Troxel, M. A.; Hartley, W.; Amara, A.; Leistedt, B.; Becker, M. R.; Bernstein, G. M.; Bridle, S. L.; Bruderer, C.; Busha, M. T.; Carrasco Kind, M.; Childress, M. J.; Castander, F. J.; Chang, C.; Crocce, M.; Davis, T. M.; Eifler, T. F.; Frieman, J.; Gangkofner, C.; Gaztanaga, E.; Glazebrook, K.; Gruen, D.; Kacprzak, T.; King, A.; Kwan, J.; Lahav, O.; Lewis, G.; Lidman, C.; Lin, H.; MacCrann, N.; Miquel, R.; O’Neill, C. R.; Palmese, A.; Peiris, H. V.; Refregier, A.; Rozo, E.; Rykoff, E. S.; Sadeh, I.; Sánchez, C.; Sheldon, E.; Uddin, S.; Wechsler, R. H.; Zuntz, J.; Abbott, T.; Abdalla, F. B.; Allam, S.; Armstrong, R.; Banerji, M.; Bauer, A. H.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carretero, J.; Cunha, C. E.; D’Andrea, C. B.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Fausti Neto, A.; Fernandez, E.; Flaugher, B.; Fosalba, P.; Gerdes, D. W.; Gruendl, R. A.; Honscheid, K.; Jain, B.; James, D. J.; Jarvis, M.; Kim, A. G.; Kuehn, K.; Kuropatkin, N.; Li, T. S.; Lima, M.; Maia, M. A. G.; March, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Miller, C. J.; Neilsen, E.; Nichol, R. C.; Nord, B.; Ogando, R.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Thomas, D.; Vikram, V.; Walker, A. R.

    2016-08-01

    We present photometric redshift estimates for galaxies used in the weak lensing analysis of the Dark Energy Survey Science Verification (DES SV) data. Four model- or machine learning-based photometric redshift methods { annz2, bpz calibrated against BCC-U fig simulations, skynet, and tpz { are analysed. For training, calibration, and testing of these methods, we also construct a catalogue of spectroscopically confirmed galaxies matched against DES SV data. The performance of the methods is evalu-ated against the matched spectroscopic catalogue, focusing on metrics relevant for weak lensing analyses, with additional validation against COSMOS photo-zs. From the galaxies in the DES SV shear catalogue, which have mean redshift 0.72 ±0.01 over the range 0:3 < z < 1:3, we construct three tomographic bins with means of z = {0.45; 0.67,1.00g}. These bins each have systematic uncertainties δz ≲ 0.05 in the mean of the fiducial skynet photo-z n(z). We propagate the errors in the redshift distributions through to their impact on cosmological parameters estimated with cosmic shear, and find that they cause shifts in the value of σ8 of approx. 3%. This shift is within the one sigma statistical errors on σ8 for the DES SV shear catalog. We also found that further study of the potential impact of systematic differences on the critical surface density, Σcrit, contained levels of bias safely less than the statistical power of DES SV data. We recommend a final Gaussian prior for the photo-z bias in the mean of n(z) of width 0:05 for each of the three tomographic bins, and show that this is a sufficient bias model for the corresponding cosmology analysis.

  12. SEARCHING FOR COOLING SIGNATURES IN STRONG LENSING GALAXY CLUSTERS: EVIDENCE AGAINST BARYONS SHAPING THE MATTER DISTRIBUTION IN CLUSTER CORES

    International Nuclear Information System (INIS)

    Blanchard, Peter K.; Bayliss, Matthew B.; McDonald, Michael; Dahle, Håkon; Gladders, Michael D.; Sharon, Keren; Mushotzky, Richard

    2013-01-01

    The process by which the mass density profile of certain galaxy clusters becomes centrally concentrated enough to produce high strong lensing (SL) cross-sections is not well understood. It has been suggested that the baryonic condensation of the intracluster medium (ICM) due to cooling may drag dark matter to the cores and thus steepen the profile. In this work, we search for evidence of ongoing ICM cooling in the first large, well-defined sample of SL selected galaxy clusters in the range 0.1 0.2 and shows no statistically significant deviation from the total cluster population. Specific star formation rates, as traced by the strength of the 4000 Å break, D 4000 , are also consistent with the general cluster population. Finally, we use optical imaging of the SL clusters to measure the angular separation, R arc , between the arc and the center of mass of each lensing cluster in our sample and test for evidence of changing [O II] emission and D 4000 as a function of R arc , a proxy observable for SL cross-sections. D 4000 is constant with all values of R arc , and the [O II] emission fractions show no dependence on R arc for R arc > 10'' and only very marginal evidence of increased weak [O II] emission for systems with R arc < 10''. These results argue against the ability of baryonic cooling associated with cool core activity in the cores of galaxy clusters to strongly modify the underlying dark matter potential, leading to an increase in SL cross-sections

  13. KiDS-450 + 2dFLenS: Cosmological parameter constraints from weak gravitational lensing tomography and overlapping redshift-space galaxy clustering

    Science.gov (United States)

    Joudaki, Shahab; Blake, Chris; Johnson, Andrew; Amon, Alexandra; Asgari, Marika; Choi, Ami; Erben, Thomas; Glazebrook, Karl; Harnois-Déraps, Joachim; Heymans, Catherine; Hildebrandt, Hendrik; Hoekstra, Henk; Klaes, Dominik; Kuijken, Konrad; Lidman, Chris; Mead, Alexander; Miller, Lance; Parkinson, David; Poole, Gregory B.; Schneider, Peter; Viola, Massimo; Wolf, Christian

    2018-03-01

    We perform a combined analysis of cosmic shear tomography, galaxy-galaxy lensing tomography, and redshift-space multipole power spectra (monopole and quadrupole) using 450 deg2 of imaging data by the Kilo Degree Survey (KiDS-450) overlapping with two spectroscopic surveys: the 2-degree Field Lensing Survey (2dFLenS) and the Baryon Oscillation Spectroscopic Survey (BOSS). We restrict the galaxy-galaxy lensing and multipole power spectrum measurements to the overlapping regions with KiDS, and self-consistently compute the full covariance between the different observables using a large suite of N-body simulations. We methodically analyse different combinations of the observables, finding that the galaxy-galaxy lensing measurements are particularly useful in improving the constraint on the intrinsic alignment amplitude, while the multipole power spectra are useful in tightening the constraints along the lensing degeneracy direction. The fully combined constraint on S_8 ≡ σ _8 √{Ω _m/0.3}=0.742± 0.035, which is an improvement by 20 per cent compared to KiDS alone, corresponds to a 2.6σ discordance with Planck, and is not significantly affected by fitting to a more conservative set of scales. Given the tightening of the parameter space, we are unable to resolve the discordance with an extended cosmology that is simultaneously favoured in a model selection sense, including the sum of neutrino masses, curvature, evolving dark energy and modified gravity. The complementarity of our observables allows for constraints on modified gravity degrees of freedom that are not simultaneously bounded with either probe alone, and up to a factor of three improvement in the S8 constraint in the extended cosmology compared to KiDS alone.

  14. Geodesic curve-of-sight formulae for the cosmic microwave background: a unified treatment of redshift, time delay, and lensing

    International Nuclear Information System (INIS)

    Saito, Ryo; Naruko, Atsushi; Hiramatsu, Takashi; Sasaki, Misao

    2014-01-01

    In this paper, we introduce a new approach to a treatment of the gravitational effects (redshift, time delay and lensing) on the observed cosmic microwave background (CMB) anisotropies based on the Boltzmann equation. From the Liouville's theorem in curved spacetime, the intensity of photons is conserved along a photon geodesic when non-gravitational scatterings are absent. Motivated by this fact, we derive a second-order line-of-sight formula by integrating the Boltzmann equation along a perturbed geodesic (curve) instead of a background geodesic (line). In this approach, the separation of the gravitational and intrinsic effects are manifest. This approach can be considered as a generalization of the remapping approach of CMB lensing, where all the gravitational effects can be treated on the same footing

  15. Next Generation Virgo Cluster Survey. XXI. The weak lensing masses of the CFHTLS and NGVS RedGOLD galaxy clusters and calibration of the optical richness

    OpenAIRE

    Parroni, Carolina; Mei, Simona; Erben, Thomas; Van Waerbeke, Ludovic; Raichoor, Anand; Ford, Jes; Licitra, Rossella; Meneghetti, Massimo; Hildebrandt, Hendrik; Miller, Lance; Côté, Patrick; Covone, Giovanni; Cuillandre, Jean-Charles; Duc, Pierre-Alain; Ferrarese, Laura

    2017-01-01

    We measured stacked weak lensing cluster masses for a sample of 1325 galaxy clusters detected by the RedGOLD algorithm in the Canada-France-Hawaii Telescope Legacy Survey W1 and the Next Generation Virgo Cluster Survey at $0.2

  16. 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.

  17. 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

  18. LoCuSS: A COMPARISON OF SUNYAEV-ZEL'DOVICH EFFECT AND GRAVITATIONAL-LENSING MEASUREMENTS OF GALAXY CLUSTERS

    International Nuclear Information System (INIS)

    Marrone, Daniel P.; Culverhouse, Thomas; Carlstrom, John E.; Greer, Christopher; Hennessy, Ryan; Leitch, Erik M.; Loh, Michael; Pryke, Clem; Smith, Graham P.; Hamilton-Morris, Victoria; Richard, Johan; Joy, Marshall; Bonamente, Massimiliano; Hasler, Nicole; Kneib, Jean-Paul; Hawkins, David; Lamb, James W.; Muchovej, Stephen; Miller, Amber; Mroczkowski, Tony

    2009-01-01

    We present the first measurement of the relationship between the Sunyaev-Zel'dovich effect (SZE) signal and the mass of galaxy clusters that uses gravitational lensing to measure cluster mass, based on 14 X-ray luminous clusters at z ≅ 0.2 from the Local Cluster Substructure Survey. We measure the integrated Compton y-parameter, Y, and total projected mass of the clusters (M GL ) within a projected clustercentric radius of 350 kpc, corresponding to mean overdensities of 4000-8000 relative to the critical density. We find self-similar scaling between M GL and Y, with a scatter in mass at fixed Y of 32%. This scatter exceeds that predicted from numerical cluster simulations, however, it is smaller than comparable measurements of the scatter in mass at fixed T X . We also find no evidence of segregation in Y between disturbed and undisturbed clusters, as had been seen with T X on the same physical scales. We compare our scaling relation to the Bonamente et al. relation based on mass measurements that assume hydrostatic equilibrium, finding no evidence for a hydrostatic mass bias in cluster cores (M GL = 0.98 ± 0.13 M HSE ), consistent with both predictions from numerical simulations and lensing/X-ray-based measurements of mass-observable scaling relations at larger radii. Overall our results suggest that the SZE may be less sensitive than X-ray observations to the details of cluster physics in cluster cores.

  19. Probing the properties of relic neutrinos using the cosmic microwave background, the Hubble Space Telescope and galaxy clusters

    Science.gov (United States)

    Nunes, Rafael C.; Bonilla, Alexander

    2018-02-01

    We investigate the observational constraints on the cosmic neutrino background (CNB) given by the extended ΛCDM scenario (ΛCDM + N_eff + \\sum m_{ν } + c^2_eff + c^2_vis + ξ _{ν }) using the latest observational data from the cosmic microwave background (CMB) as observed by Planck (i.e. temperature power spectrum, low-polarization and lensing reconstruction), baryon acoustic oscillations (BAOs), the new recent local value of the Hubble constant from the Hubble Space Telescope (HST) and information on the abundance of galaxy clusters (GCs). We study the constraints on the CNB background using CMB + BAO + HST data with and without the GC data. We find ΔNeff = 0.614 ± 0.26 at the 68 per cent confidence level when the GC data are added to the analysis. We do not find any significant deviation for sound speed in the CNB rest frame. We also analyse the particular case ΛCDM +Neff + ∑mν + ξν with the observational data. Within this scenario, we find ΔNeff = 0.60 ± 0.28 at the 68 per cent confidence level. In both scenarios, no mean deviations are found for the degeneracy parameter.

  20. The number counts and infrared backgrounds from infrared-bright galaxies

    International Nuclear Information System (INIS)

    Hacking, P.B.; Soifer, B.T.

    1991-01-01

    Extragalactic number counts and diffuse backgrounds at 25, 60, and 100 microns are predicted using new luminosity functions and improved spectral-energy distribution density functions derived from IRAS observations of nearby galaxies. Galaxies at redshifts z less than 3 that are like those in the local universe should produce a minimum diffuse background of 0.0085, 0.038, and 0.13 MJy/sr at 25, 60, and 100 microns, respectively. Models with significant luminosity evolution predict backgrounds about a factor of 4 greater than this minimum. 22 refs

  1. The impact of ΛCDM substructure and baryon-dark matter transition on the image positions of quad galaxy lenses

    Science.gov (United States)

    Gomer, Matthew R.; Williams, Liliya L. R.

    2018-04-01

    The positions of multiple images in galaxy lenses are related to the galaxy mass distribution. Smooth elliptical mass profiles were previously shown to be inadequate in reproducing the quad population. In this paper, we explore the deviations from such smooth elliptical mass distributions. Unlike most other work, we use a model-free approach based on the relative polar image angles of quads, and their position in 3D space with respect to the fundamental surface of quads (FSQ). The FSQ is defined by quads produced by elliptical lenses. We have generated thousands of quads from synthetic populations of lenses with substructure consistent with Lambda cold dark matter (ΛCDM) simulations, and found that such perturbations are not sufficient to match the observed distribution of quads relative to the FSQ. The result is unchanged even when subhalo masses are increased by a factor of 10, and the most optimistic lensing selection bias is applied. We then produce quads from galaxies created using two components, representing baryons and dark matter. The transition from the mass being dominated by baryons in inner radii to being dominated by dark matter in outer radii can carry with it asymmetries, which would affect relative image angles. We run preliminary experiments using lenses with two elliptical mass components with non-identical axial ratios and position angles, perturbations from ellipticity in the form of non-zero Fourier coefficients a4 and a6, and artificially offset ellipse centres as a proxy for asymmetry at image radii. We show that combination of these effects is a promising way of accounting for quad population properties. We conclude that the quad population provides a unique and sensitive tool for constraining detailed mass distribution in the centres of galaxies.

  2. Observations of Cluster Substructure using Weakly Lensed Sextupole Moments

    Energy Technology Data Exchange (ETDEWEB)

    Irwin, John

    2003-08-01

    Since dark matter clusters and groups may have substructure, we have examined the sextupole content of Hubble images looking for a curvature signature in background galaxies that would arise from galaxy-galaxy lensing. We describe techniques for extracting and analyzing sextupole and higher weakly lensed moments. Indications of substructure, via spatial clumping of curved background galaxies, were observed in the image of CL0024 and then surprisingly in both Hubble deep fields. We estimate the dark cluster masses in the deep field. Alternatives to a lensing hypothesis appear improbable, but better statistics will be required to exclude them conclusively. Observation of sextupole moments would then provide a means to measure dark matter structure on smaller length scales than heretofore.

  3. Relieving the tension between weak lensing and cosmic microwave background with interacting dark matter and dark energy models

    Science.gov (United States)

    An, Rui; Feng, Chang; Wang, Bin

    2018-02-01

    We constrain interacting dark matter and dark energy (IDMDE) models using a 450-degree-square cosmic shear data from the Kilo Degree Survey (KiDS) and the angular power spectra from Planck's latest cosmic microwave background measurements. We revisit the discordance problem in the standard Lambda cold dark matter (ΛCDM) model between weak lensing and Planck datasets and extend the discussion by introducing interacting dark sectors. The IDMDE models are found to be able to alleviate the discordance between KiDS and Planck as previously inferred from the ΛCDM model, and moderately favored by a combination of the two datasets.

  4. Cross-correlation Weak Lensing of SDSS galaxy Clusters II: Cluster Density Profiles and the Mass--Richness Relation

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, David E.; Sheldon, Erin S.; Wechsler, Risa H.; Rozo, Eduardo; Koester, Benjamin P.; Frieman, Joshua A.; McKay, Timothy A.; Evrard, August E.; Becker, Matthew; Annis, James

    2007-09-28

    We interpret and model the statistical weak lensing measurements around 130,000 groups and clusters of galaxies in the Sloan Digital Sky Survey presented by Sheldon et al. (2007). We present non-parametric inversions of the 2D shear profiles to the mean 3D cluster density and mass profiles in bins of both optical richness and cluster i-band luminosity. Since the mean cluster density profile is proportional to the cluster-mass correlation function, the mean profile is spherically symmetric by the assumptions of large-scale homogeneity and isotropy. We correct the inferred 3D profiles for systematic effects, including non-linear shear and the fact that cluster halos are not all precisely centered on their brightest galaxies. We also model the measured cluster shear profile as a sum of contributions from the brightest central galaxy, the cluster dark matter halo, and neighboring halos. We infer the relations between mean cluster virial mass and optical richness and luminosity over two orders of magnitude in cluster mass; the virial mass at fixed richness or luminosity is determined with a precision of {approx} 13% including both statistical and systematic errors. We also constrain the halo concentration parameter and halo bias as a function of cluster mass; both are in good agreement with predictions from N-body simulations of LCDM models. The methods employed here will be applicable to deeper, wide-area optical surveys that aim to constrain the nature of the dark energy, such as the Dark Energy Survey, the Large Synoptic Survey Telescope and space-based surveys.

  5. Electroweak corrections to photon scattering, polarization and lensing in a gravitational background and the near horizon limit

    Energy Technology Data Exchange (ETDEWEB)

    Corianò, Claudio; Rose, Luigi Delle; Maglio, Matteo Maria [Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento and INFN-Lecce,Via Arnesano, 73100 Lecce (Italy); Serino, Mirko [Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento and INFN-Lecce,Via Arnesano, 73100 Lecce (Italy); Institute of Nuclear Physics, Polish Academy of Sciences,ul. Radzikowskiego 152, 31-342 Krakow (Poland)

    2015-01-19

    We investigate the semiclassical approach to the lensing of photons in a spherically symmetric gravitational background, starting from Born level and include in our analysis the radiative corrections obtained from the electroweak theory for the graviton/photon/photon vertex. In this approach, the cross section is related to the angular variation of the impact parameter (b), which is then solved for b as a function of the angle of deflection, and measured in horizon units (b{sub h}≡b/(2GM)). Exact numerical solutions for the angular deflection are presented. The numerical analysis shows that perturbation theory in a weak background agrees with the classical Einstein formula for the deflection already at distances of the order of 20 horizon units (∼20 b{sub h}) and it is optimal in the description both of very strong and weak lensings. We show that the electroweak corrections to the cross section are sizeable, becoming very significant for high energy gamma rays. Our analysis covers in energy most of the photon spectrum, from the cosmic microwave background up to very high energy gamma rays, and scatterings with any value of the photon impact parameter. We also study the helicity-flip photon amplitude, which is of O(α{sup 2}) in the weak coupling α, and its massless fermion limit, which involves the exchange of a conformal anomaly pole. The corresponding cross section is proportional to the Born level result and brings to a simple renormalization of Einsten’s formula.

  6. Hot gas in clusters of galaxies, cosmic microwave background radiation and cosmology

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    Presence of the hot (kTe ~ 3 - 10 KeV) rarefied gas in the clusters of galaxies (most massive gravitationally bound objects in the Universe) leads to the appearance of  "shadows"  in the angular distribution of the Cosmic Microwave Background (CMB) Radiation and permits to measure the peculiar velocities of these clusters relative to the unique coordinate frame where CMB is isotropic. I plan to describe the physics leading to these observational effects. Planck spacecraft, ground based South Pole and Atacama Cosmology Telescopes discovered recently more than two thousand of unknown before Clusters of Galaxies at high redshifts detecting these "shadows" and traces of kinematic effect, demonstrating the correlation of the hot gas velocities with mass concentrations on large scales. Giant ALMA interferometer in Atacama desert resolved recently strong shocks between merging clusters of galaxies. Newly discovered clusters of galaxies permit to study the rate of growth of the large scale structur...

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

    NARCIS (Netherlands)

    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.

    2017-01-01

    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

  8. 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.

  9. A Measurement of CMB Cluster Lensing with SPT and DES Year 1 Data

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, E.J.; et al.

    2017-08-03

    Clusters of galaxies gravitationally lens the cosmic microwave background (CMB) radiation, resulting in a distinct imprint in the CMB on arcminute scales. Measurement of this effect offers a promising way to constrain the masses of galaxy clusters, particularly those at high redshift. We use CMB maps from the South Pole Telescope Sunyaev-Zel'dovich (SZ) survey to measure the CMB lensing signal around galaxy clusters identified in optical imaging from first year observations of the Dark Energy Survey. We detect lensing of the CMB by the galaxy clusters at 6.5$\\sigma$ significance. Using the measured lensing signal, we constrain the amplitude of the relation between cluster mass and optical richness to roughly $20\\%$ precision, finding good agreement with recent constraints obtained with galaxy lensing. The error budget is dominated by statistical noise but includes significant contributions from systematic biases due to the thermal SZ effect and cluster miscentering.

  10. The Unresolved Star-Forming Galaxy Component of the Extragalactic Gamma Ray Background

    Science.gov (United States)

    Venters, Tonia M.; Stecker, F. W.

    2011-01-01

    We present new theoretical estimates of the contribution of unresolved star-forming galaxies to the extragalactic gamma-ray background (EGB) as measured by EGRET and the Fermi-LAT. We employ several methods for determining the star-forming galaxy contribution the the EGB, including a method positing a correlation between the gamma-ray luminosity of a galaxy and its rate of star formation as calculated from the total infrared luminosity, and a method that makes use of a model of the evolution of the galaxy gas mass with cosmic time. We find that depending on the model, unresolved star-forming galaxies could contribute significantly to the EGB as measured by the Fermi-LAT at energies between approx. 300 MeV and approx. few GeV. However, the overall spectrum of unresolved star-forming galaxies can explain neither the EGRET EGB spectrum at energies between 50 and 200 MeV nor the Fermi-LAT EGB spectrum at energies above approx. few GeV.

  11. Extragalactic gamma-ray background from AGN winds and star-forming galaxies in cosmological galaxy-formation models

    Science.gov (United States)

    Lamastra, A.; Menci, N.; Fiore, F.; Antonelli, L. A.; Colafrancesco, S.; Guetta, D.; Stamerra, A.

    2017-10-01

    We derive the contribution to the extragalactic gamma-ray background (EGB) from active galactic nuclei (AGN) winds and star-forming galaxies by including a physical model for the γ-ray emission produced by relativistic protons accelerated by AGN-driven and supernova-driven shocks into a state-of-the-art semi-analytic model of galaxy formation. This is based on galaxy interactions as triggers of AGN accretion and starburst activity and on expanding blast waves as the mechanism to communicate outwards the energy injected into the interstellar medium by the active nucleus. We compare the model predictions with the latest measurement of the EGB spectrum performed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi) in the range between 100 MeV and 820 GeV. We find that AGN winds can provide 35 ± 15% of the observed EGB in the energy interval Eγ = 0.1-1 GeV, for 73 ± 15% at Eγ = 1-10 GeV, and for 60 ± 20% at Eγ ≳10 GeV. The AGN wind contribution to the EGB is predicted to be larger by a factor of 3-5 than that provided by star-forming galaxies (quiescent plus starburst) in the hierarchical clustering scenario. The cumulative γ-ray emission from AGN winds and blazars can account for the amplitude and spectral shape of the EGB, assuming the standard acceleration theory, and AGN wind parameters that agree with observations. We also compare the model prediction for the cumulative neutrino background from AGN winds with the most recent IceCube data. We find that for AGN winds with accelerated proton spectral index p = 2.2-2.3, and taking into account internal absorption of γ-rays, the Fermi-LAT and IceCube data could be reproduced simultaneously.

  12. Weak-lensing mass calibration of redMaPPer galaxy clusters in Dark Energy Survey Science Verification data

    Energy Technology Data Exchange (ETDEWEB)

    Melchior, P.; Gruen, D.; McClintock, T.; Varga, T. N.; Sheldon, E.; Rozo, E.; Amara, A.; Becker, M. R.; Benson, B. A.; Bermeo, A.; Bridle, S. L.; Clampitt, J.; Dietrich, J. P.; Hartley, W. G.; Hollowood, D.; Jain, B.; Jarvis, M.; Jeltema, T.; Kacprzak, T.; MacCrann, N.; Rykoff, E. S.; Saro, A.; Suchyta, E.; Troxel, M. A.; Zuntz, J.; Bonnett, C.; Plazas, A. A.; Abbott, T. M. C.; Abdalla, F. B.; Annis, J.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; D’Andrea, C. B.; da Costa, L. N.; Desai, S.; Eifler, T. F.; Flaugher, B.; Fosalba, P.; García-Bellido, J.; Gaztanaga, E.; Gerdes, D. W.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kirk, D.; Krause, E.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; Maia, M. A. G.; March, M.; Martini, P.; Menanteau, F.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Ogando, R.; Romer, A. K.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.; Weller, J.; Zhang, Y.

    2017-05-16

    We use weak-lensing shear measurements to determine the mean mass of optically selected galaxy clusters in Dark Energy Survey Science Verification data. In a blinded analysis, we split the sample of more than 8,000 redMaPPer clusters into 15 subsets, spanning ranges in the richness parameter $5 \\leq \\lambda \\leq 180$ and redshift $0.2 \\leq z \\leq 0.8$, and fit the averaged mass density contrast profiles with a model that accounts for seven distinct sources of systematic uncertainty: shear measurement and photometric redshift errors; cluster-member contamination; miscentering; deviations from the NFW halo profile; halo triaxiality; and line-of-sight projections. We combine the inferred cluster masses to estimate the joint scaling relation between mass, richness and redshift, $\\mathcal{M}(\\lambda,z) \\varpropto M_0 \\lambda^{F} (1+z)^{G}$. We find $M_0 \\equiv \\langle M_{200\\mathrm{m}}\\,|\\,\\lambda=30,z=0.5\\rangle=\\left[ 2.35 \\pm 0.22\\ \\rm{(stat)} \\pm 0.12\\ \\rm{(sys)} \\right] \\cdot 10^{14}\\ M_\\odot$, with $F = 1.12\\,\\pm\\,0.20\\ \\rm{(stat)}\\, \\pm\\, 0.06\\ \\rm{(sys)}$ and $G = 0.18\\,\\pm\\, 0.75\\ \\rm{(stat)}\\, \\pm\\, 0.24\\ \\rm{(sys)}$. The amplitude of the mass-richness relation is in excellent agreement with the weak-lensing calibration of redMaPPer clusters in SDSS by Simet et al. (2016) and with the Saro et al. (2015) calibration based on abundance matching of SPT-detected clusters. Our results extend the redshift range over which the mass-richness relation of redMaPPer clusters has been calibrated with weak lensing from $z\\leq 0.3$ to $z\\leq0.8$. Calibration uncertainties of shear measurements and photometric redshift estimates dominate our systematic error budget and require substantial improvements for forthcoming studies.

  13. Early Science with the Large Millimeter Telescope: Detection of Dust Emission in Multiple Images of a Normal Galaxy at z > 4 Lensed by a Frontier Fields Cluster

    Energy Technology Data Exchange (ETDEWEB)

    Pope, Alexandra; Battisti, Andrew; Wilson, Grant W.; Calzetti, Daniela; Cybulski, Ryan; Giavalisco, Mauro; Kirkpatrick, Allison [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Montaña, Alfredo; Aretxaga, Itziar; Hughes, David [Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), Luis Enrique Erro 1, Sta. Ma. Tonantzintla, 72840 Puebla (Mexico); Limousin, Marceau [Aix Marseille Univ, CNRS, LAM, Laboratoire d' Astrophysique de Marseille, Marseille (France); Marchesini, Danilo; Kado-Fong, Erin [Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States); Alberts, Stacey [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Avila-Reese, Vladimir [Instituto de Astronomía, Universidad Nacional Autónoma de México, A.P. 70-264, 04510, CDMX (Mexico); Bermejo-Climent, José Ramón [Departamento de Astrofísica, Universidad de La Laguna. Vía Láctea s/n, La Laguna 38200, Tenerife (Spain); Brammer, Gabriel [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Bravo-Alfaro, Hector [Departamento de Astronomia, Universidad de Guanajuato, Apdo. Postal 144, Guanajuato 36000 (Mexico); Chary, Ranga-Ram [Infrared Processing and Analysis Center, MS314-6, California Institute of Technology, Pasadena, CA 91125 (United States); Keller, Erica, E-mail: pope@astro.umass.edu [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); and others

    2017-04-01

    We directly detect dust emission in an optically detected, multiply imaged galaxy lensed by the Frontier Fields cluster MACSJ0717.5+3745. We detect two images of the same galaxy at 1.1 mm with the AzTEC camera on the Large Millimeter Telescope leaving no ambiguity in the counterpart identification. This galaxy, MACS0717-Az9, is at z > 4 and the strong lensing model ( μ = 7.5) allows us to calculate an intrinsic IR luminosity of 9.7 × 10{sup 10} L {sub ⊙} and an obscured star formation rate of 14.6 ± 4.5 M {sub ⊙} yr{sup −1}. The unobscured star formation rate from the UV is only 4.1 ± 0.3 M {sub ⊙} yr{sup −1}, which means the total star formation rate (18.7 ± 4.5 M {sub ⊙} yr{sup −1}) is dominated (75%–80%) by the obscured component. With an intrinsic stellar mass of only 6.9 × 10{sup 9} M {sub ⊙}, MACS0717-Az9 is one of only a handful of z > 4 galaxies at these lower masses that is detected in dust emission. This galaxy lies close to the estimated star formation sequence at this epoch. However, it does not lie on the dust obscuration relation (IRX- β ) for local starburst galaxies and is instead consistent with the Small Magellanic Cloud attenuation law. This remarkable lower mass galaxy, showing signs of both low metallicity and high dust content, may challenge our picture of dust production in the early universe.

  14. Gravitational lensing and microlensing

    CERN Document Server

    Mollerach, Silvia

    2002-01-01

    This book provides a comprehensive and self-contained exposition of gravitational lensing phenomena. It presents the up-to-date status of gravitational lensing and microlensing, covering the cosmological applications of the observed lensing by galaxies, clusters and the large scale structures, as well as the microlensing searches in the Local Group and its applications to unveil the nature of the galactic dark matter, the search for planetary objects and the distribution of faint stars in our galaxy. Gravitational Lensing and Microlensing is pitched at the level of the graduate student interes

  15. HST Grism Observations of a Gravitationally Lensed Redshift 9.5 Galaxy

    Science.gov (United States)

    Hoag, A.; Bradač, M.; Brammer, G.; Huang, K.-H.; Treu, T.; Mason, C. A.; Castellano, M.; Di Criscienzo, M.; Jones, T.; Kelly, P.; Pentericci, L.; Ryan, R.; Schmidt, K.; Trenti, M.

    2018-02-01

    We present deep spectroscopic observations of a Lyman break galaxy (LBG) candidate (hereafter MACS1149-JD) at z ∼ 9.5 with the Hubble Space Telescope (HST) WFC3/IR grisms. The grism observations were taken at four distinct position angles, totaling 34 orbits with the G141 grism, although only 19 of the orbits are relatively uncontaminated along the trace of MACS1149-JD. We fit a three-parameter (z, F160W mag, and Lyα equivalent width [EW]) LBG template to the three least contaminated grism position angles using a Markov chain Monte Carlo approach. The grism data alone are best fit with a redshift of {z}{grism}={9.53}-0.60+0.39 (68% confidence), in good agreement with our photometric estimate of {z}{phot}={9.51}-0.12+0.06 (68% confidence). Our analysis rules out Lyα emission from MACS1149-JD above a 3σ EW of 21 Å, consistent with a highly neutral IGM. We explore a scenario where the red Spitzer/IRAC [3.6]–[4.5] color of the galaxy previously pointed out in the literature is due to strong rest-frame optical emission lines from a very young stellar population rather than a 4000 Å break. We find that while this can provide an explanation for the observed IRAC color, it requires a lower redshift (z ≲ 9.1), which is less preferred by the HST imaging data. The grism data are consistent with both scenarios, indicating that the red IRAC color can still be explained by a 4000 Å break, characteristic of a relatively evolved stellar population. In this interpretation, the photometry indicates that a {340}-35+29 Myr stellar population is already present in this galaxy only ∼500 Myr after the big bang.

  16. 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

  17. MERGERS OF LUMINOUS EARLY-TYPE GALAXIES IN THE LOCAL UNIVERSE AND GRAVITATIONAL WAVE BACKGROUND

    International Nuclear Information System (INIS)

    Wen, Z. L.; Liu, F. S.; Han, J. L.

    2009-01-01

    Supermassive black hole (SMBH) coalescence in galaxy mergers is believed to be one of the primary sources of very low frequency gravitational waves (GWs). Significant contribution of the GWs comes from mergers of massive galaxies with redshifts z p r g ∼ (1.0 ± 0.4) x 10 -5 Mpc -3 Gyr -1 with an uncertainty mainly depending on the merging timescale. We estimated the masses of SMBHs in the centers of merging galaxies based on their luminosities. We found that the chirp mass distribution of the SMBH binaries follows a power law with an index of -3.0 ± 0.5 in the range 5 x 10 8 -5 x 10 9 M sun . Using the SMBH population in the mergers and assuming that the SMBHs can be efficiently driven into the GW regime, we investigated the stochastic GW background in the frequency range 10 -9 -10 -7 Hz. We obtained the spectrum of the GW background of h c (f) ∼ 10 -15 (f/yr -1 ) -2/3 , which is one magnitude higher than that obtained by Jaffe and Backer in 2003, but consistent with those calculated from galaxy-formation models.

  18. Weak lensing of the Lyman-alpha forest

    Science.gov (United States)

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

    2018-03-01

    The angular positions of quasars are deflected by the gravitational lensing effect of foreground matter. The Lyα forest seen in the spectra of these quasars is therefore also lensed. We propose that the signature of weak gravitional lensing of the Lyα forest could be measured using similar techniques that have been applied to the lensed Cosmic Microwave Background, and which have also been proposed for application to spectral data from 21cm radio telescopes. As with 21cm 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.

  19. Near-infrared background anisotropies from diffuse intrahalo light of galaxies

    Science.gov (United States)

    Cooray, Asantha; Smidt, Joseph; de Bernardis, Francesco; Gong, Yan; Stern, Daniel; Ashby, Matthew L. N.; Eisenhardt, Peter R.; Frazer, Christopher C.; Gonzalez, Anthony H.; Kochanek, Christopher S.; Kozłowski, Szymon; Wright, Edward L.

    2012-10-01

    Unresolved anisotropies of the cosmic near-infrared background radiation are expected to have contributions from the earliest galaxies during the epoch of reionization and from faint, dwarf galaxies at intermediate redshifts. Previous measurements were unable to pinpoint conclusively the dominant origin because they did not sample spatial scales that were sufficiently large to distinguish between these two possibilities. Here we report a measurement of the anisotropy power spectrum from subarcminute to one-degree angular scales, and find the clustering amplitude to be larger than predicted by the models based on the two existing explanations. As the shot-noise level of the power spectrum is consistent with that expected from faint galaxies, a new source population on the sky is not necessary to explain the observations. However, a physical mechanism that increases the clustering amplitude is needed. Motivated by recent results related to the extended stellar light profile in dark-matter haloes, we consider the possibility that the fluctuations originate from intrahalo stars of all galaxies. We find that the measured power spectrum can be explained by an intrahalo light fraction of 0.07 to 0.2 per cent relative to the total luminosity in dark-matter haloes of 109 to 1012 solar masses at redshifts of about 1 to 4.

  20. Near-infrared background anisotropies from diffuse intrahalo light of galaxies.

    Science.gov (United States)

    Cooray, Asantha; Smidt, Joseph; De Bernardis, Francesco; Gong, Yan; Stern, Daniel; Ashby, Matthew L N; Eisenhardt, Peter R; Frazer, Christopher C; Gonzalez, Anthony H; Kochanek, Christopher S; Kozłowski, Szymon; Wright, Edward L

    2012-10-25

    Unresolved anisotropies of the cosmic near-infrared background radiation are expected to have contributions from the earliest galaxies during the epoch of reionization and from faint, dwarf galaxies at intermediate redshifts. Previous measurements were unable to pinpoint conclusively the dominant origin because they did not sample spatial scales that were sufficiently large to distinguish between these two possibilities. Here we report a measurement of the anisotropy power spectrum from subarcminute to one-degree angular scales, and find the clustering amplitude to be larger than predicted by the models based on the two existing explanations. As the shot-noise level of the power spectrum is consistent with that expected from faint galaxies, a new source population on the sky is not necessary to explain the observations. However, a physical mechanism that increases the clustering amplitude is needed. Motivated by recent results related to the extended stellar light profile in dark-matter haloes, we consider the possibility that the fluctuations originate from intrahalo stars of all galaxies. We find that the measured power spectrum can be explained by an intrahalo light fraction of 0.07 to 0.2 per cent relative to the total luminosity in dark-matter haloes of 10(9) to 10(12) solar masses at redshifts of about 1 to 4.

  1. The masses of satellites in GAMA galaxy groups from 100 square degrees of KiDS weak lensing data

    NARCIS (Netherlands)

    Sifón, Cristóbal; Cacciato, Marcello; Hoekstra, Henk; Brouwer, Margot; van Uitert, Edo; Viola, Massimo; Baldry, Ivan; Brough, Sarah; Brown, Michael J. I.; Choi, Ami; Driver, Simon P.; Erben, Thomas; Grado, Aniello; Heymans, Catherine; Hildebrandt, Hendrik; Joachimi, Benjamin; de Jong, Jelte T. A.; Kuijken, Konrad; McFarland, John; Miller, Lance; Nakajima, Reiko; Napolitano, Nicola; Norberg, Peder; Robotham, Aaron S. G.; Schneider, Peter; Kleijn, Gijs Verdoes

    2015-01-01

    We use the first 100 deg2 of overlap between the Kilo-Degree Survey and the Galaxy And Mass Assembly survey to determine the average galaxy halo mass of ˜10 000 spectroscopically confirmed satellite galaxies in massive (M > 1013 h-1 M⊙) galaxy groups. Separating the sample as a function of projected

  2. Cluster Mass Calibration at High Redshift: HST Weak Lensing Analysis of 13 Distant Galaxy Clusters from the South Pole Telescope Sunyaev-Zel'dovich Survey

    Energy Technology Data Exchange (ETDEWEB)

    Schrabback, T.; et al.

    2016-11-11

    We present an HST/ACS weak gravitational lensing analysis of 13 massive high-redshift (z_median=0.88) galaxy clusters discovered in the South Pole Telescope (SPT) Sunyaev-Zel'dovich Survey. This study is part of a larger campaign that aims to robustly calibrate mass-observable scaling relations over a wide range in redshift to enable improved cosmological constraints from the SPT cluster sample. We introduce new strategies to ensure that systematics in the lensing analysis do not degrade constraints on cluster scaling relations significantly. First, we efficiently remove cluster members from the source sample by selecting very blue galaxies in V-I colour. Our estimate of the source redshift distribution is based on CANDELS data, where we carefully mimic the source selection criteria of the cluster fields. We apply a statistical correction for systematic photometric redshift errors as derived from Hubble Ultra Deep Field data and verified through spatial cross-correlations. We account for the impact of lensing magnification on the source redshift distribution, finding that this is particularly relevant for shallower surveys. Finally, we account for biases in the mass modelling caused by miscentring and uncertainties in the mass-concentration relation using simulations. In combination with temperature estimates from Chandra we constrain the normalisation of the mass-temperature scaling relation ln(E(z) M_500c/10^14 M_sun)=A+1.5 ln(kT/7.2keV) to A=1.81^{+0.24}_{-0.14}(stat.) +/- 0.09(sys.), consistent with self-similar redshift evolution when compared to lower redshift samples. Additionally, the lensing data constrain the average concentration of the clusters to c_200c=5.6^{+3.7}_{-1.8}.

  3. Cluster Mass Calibration at High Redshift: HST Weak Lensing Analysis of 13 Distant Galaxy Clusters from the South Pole Telescope Sunyaev-Zel’dovich Survey

    Energy Technology Data Exchange (ETDEWEB)

    Schrabback, T.; Applegate, D.; Dietrich, J. P.; Hoekstra, H.; Bocquet, S.; Gonzalez, A. H.; der Linden, A. von; McDonald, M.; Morrison, C. B.; Raihan, S. F.; Allen, S. W.; Bayliss, M.; Benson, B. A.; Bleem, L. E.; Chiu, I.; Desai, S.; Foley, R. J.; de Haan, T.; High, F. W.; Hilbert, S.; Mantz, A. B.; Massey, R.; Mohr, J.; Reichardt, C. L.; Saro, A.; Simon, P.; Stern, C.; Stubbs, C. W.; Zenteno, A.

    2017-10-14

    We present an HST/Advanced Camera for Surveys (ACS) weak gravitational lensing analysis of 13 massive high-redshift (z(median) = 0.88) galaxy clusters discovered in the South Pole Telescope (SPT) Sunyaev-Zel'dovich Survey. This study is part of a larger campaign that aims to robustly calibrate mass-observable scaling relations over a wide range in redshift to enable improved cosmological constraints from the SPT cluster sample. We introduce new strategies to ensure that systematics in the lensing analysis do not degrade constraints on cluster scaling relations significantly. First, we efficiently remove cluster members from the source sample by selecting very blue galaxies in V - I colour. Our estimate of the source redshift distribution is based on Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) data, where we carefully mimic the source selection criteria of the cluster fields. We apply a statistical correction for systematic photometric redshift errors as derived from Hubble Ultra Deep Field data and verified through spatial cross-correlations. We account for the impact of lensing magnification on the source redshift distribution, finding that this is particularly relevant for shallower surveys. Finally, we account for biases in the mass modelling caused by miscentring and uncertainties in the concentration-mass relation using simulations. In combination with temperature estimates from Chandra we constrain the normalization of the mass-temperature scaling relation ln (E(z) M-500c/10(14)M(circle dot)) = A + 1.5ln (kT/7.2 keV) to A = 1.81(-0.14)(+0.24)(stat.)+/- 0.09(sys.), consistent with self-similar redshift evolution when compared to lower redshift samples. Additionally, the lensing data constrain the average concentration of the clusters to c(200c) = 5.6(-1.8)(+3.7).

  4. Cumulative Neutrino and Gamma-Ray Backgrounds from Halo and Galaxy Mergers

    Science.gov (United States)

    Yuan, Chengchao; Mészáros, Peter; Murase, Kohta; Jeong, Donghui

    2018-04-01

    The merger of dark matter halos and the gaseous structures embedded in them, such as protogalaxies, galaxies, and groups and clusters of galaxies, results in strong shocks that are capable of accelerating cosmic rays (CRs) to ≳10 PeV. These shocks will produce high-energy neutrinos and γ-rays through inelastic pp collisions. In this work, we study the contributions of these halo mergers to the diffuse neutrino flux and to the nonblazar portion of the extragalactic γ-ray background. We formulate the redshift dependence of the shock velocity, galactic radius, halo gas content, and galactic/intergalactic magnetic fields over the dark matter halo distribution up to a redshift z = 10. We find that high-redshift mergers contribute a significant amount of the CR luminosity density, and the resulting neutrino spectra could explain a large part of the observed diffuse neutrino flux above 0.1 PeV up to several PeV. We also show that our model can somewhat alleviate tensions with the extragalactic γ-ray background. First, since a larger fraction of the CR luminosity density comes from high redshifts, the accompanying γ-rays are more strongly suppressed through γγ annihilations with the cosmic microwave background and the extragalactic background light. Second, mildly radiative-cooled shocks may lead to a harder CR spectrum with spectral indices of 1.5 ≲ s ≲ 2.0. Our study suggests that halo mergers, a fraction of which may also induce starbursts in the merged galaxies, can be promising neutrino emitters without violating the existing Fermi γ-ray constraints on the nonblazar component of the extragalactic γ-ray background.

  5. Ultra-faint ultraviolet galaxies at z ∼ 2 behind the lensing cluster A1689: The luminosity function, dust extinction, and star formation rate density

    Energy Technology Data Exchange (ETDEWEB)

    Alavi, Anahita; Siana, Brian; Freeman, William R.; Dominguez, Alberto [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Richard, Johan [Centre de Recherche Astrophysique de Lyon, Université Lyon 1, 9 Avenue Charles André, F-69561 Saint Genis Laval Cedex (France); Stark, Daniel P.; Robertson, Brant [Department of Astronomy, Steward Observatory, University of Arizona, 933 North Cherry Avenue, Rm N204, Tucson, AZ 85721 (United States); Scarlata, Claudia [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Teplitz, Harry I.; Rafelski, Marc [Infrared Processing and Analysis Center, Caltech, Pasadena, CA 91125 (United States); Kewley, Lisa, E-mail: anahita.alavi@email.ucr.edu [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia)

    2014-01-10

    We have obtained deep ultraviolet imaging of the lensing cluster A1689 with the WFC3/UVIS camera onboard the Hubble Space Telescope in the F275W (30 orbits) and F336W (4 orbits) filters. These images are used to identify z ∼ 2 star-forming galaxies via their Lyman break, in the same manner that galaxies are typically selected at z ≥ 3. Because of the unprecedented depth of the images and the large magnification provided by the lensing cluster, we detect galaxies 100× fainter than previous surveys at this redshift. After removing all multiple images, we have 58 galaxies in our sample in the range –19.5 < M {sub 1500} < –13 AB mag. Because the mass distribution of A1689 is well constrained, we are able to calculate the intrinsic sensitivity of the observations as a function of source plane position, allowing for accurate determinations of effective volume as a function of luminosity. We fit the faint-end slope of the luminosity function to be α = –1.74 ± 0.08, which is consistent with the values obtained for 2.5 < z < 6. Notably, there is no turnover in the luminosity function down to M {sub 1500} = –13 AB mag. We fit the UV spectral slopes with photometry from existing Hubble optical imaging. The observed trend of increasingly redder slopes with luminosity at higher redshifts is observed in our sample, but with redder slopes at all luminosities and average reddening of (E(B – V)) = 0.15 mag. We assume the stars in these galaxies are metal poor (0.2 Z {sub ☉}) compared to their brighter counterparts (Z {sub ☉}), resulting in bluer assumed intrinsic UV slopes and larger derived values for dust extinction. The total UV luminosity density at z ∼ 2 is 4.31{sub −0.60}{sup +0.68}×10{sup 26} erg s{sup –1} Hz{sup –1} Mpc{sup –3}, more than 70% of which is emitted by galaxies in the luminosity range of our sample. Finally, we determine the global star formation rate density from UV-selected galaxies at z ∼ 2 (assuming a constant dust

  6. Gravitational Lensing Signatures of Long Cosmic Strings

    CERN Document Server

    De Laix, A A; Vachaspati, T; Laix, Andrew A. de; Krauss, Lawrence M.; Vachaspati, Tanmay

    1997-01-01

    The gravitational lensing by long, wiggly cosmic strings is shown to produce a large number of lensed images of a background source. In addition to pairs of images on either side of the string, a number of small images outline the string due to small-scale structure on the string. This image pattern could provide a highly distinctive signature of cosmic strings. Since the optical depth for multiple imaging of distant quasar sources by long strings may be comparable to that by galaxies, these image patterns should be clearly observable in the next generation of redshift surveys such as the Sloan Digital Sky Survey.

  7. The Effects of Nearby Clusters of Galaxies on the Microwave Background Radiation

    Science.gov (United States)

    Birkinshaw, M.

    1999-01-01

    This project proposed to use the COBE (Cosmic Background Explorer) DMR sky-maps to measure the anisotropies introduced into the microwave background radiation by the Sunyaev-Zel'dovich and Rees-Sciama effects of nearby clusters and superclusters of galaxies. We intended to seek these effects by making maps of the best-fit anisotropies on particular angular scales and comparing the apparent anisotropies near target clusters and superclusters with the statistical noise and sky variance. The locations of the clusters and superclusters were to be found using HEAO-1 (High Energy Astronomy Observatory) A2 and Einstein X-ray maps. Checks against biases were to be made using radio and X-ray sky-maps as guides to the properties of the clusters and superclusters. Any signals detected would have implications for the gas properties and baryonic masses of clusters and superclusters. The scientific background, project activities and references to published papers are included.

  8. Galaxies

    International Nuclear Information System (INIS)

    1981-01-01

    Normal galaxies, radio galaxies, and Seyfert galaxies are considered. The large magellanic cloud and the great galaxy in Andromedia are highlighted. Quasars and BL lacertae objects are also discussed and a review of the spectral observations of all of these galaxies and celestial objects is presented

  9. Starburst Galaxies: Hard X-ray spectra and contribution to the diffuse background

    Science.gov (United States)

    Gruber, Duane E.

    1993-01-01

    During the period of this grant two main tasks were performed: a determination of a selection criterion for starburst galaxies most likely to emit X-rays, and performance of a pilot study of the X-ray emission from nine such systems. Starburst galaxies may be expected to emit flat-spectrum X-ray at energies above 10 keV resulting from the various remnants of the short-lived massive stars which characterize the starburst. The investigation to determine the optimum sample resulted in a change from an X-ray selected (HEAO-2) sample to infrared selection based on the IRAS catalogue. A much broader sample thereby available for study, and selection could be limited to only the nearest objects and still obtain a reasonably large sample. A sample of 99 of the brightest infrared starburst galaxies was settled on for the X-ray survey. For a set of practical size, this was then reduced to a subset of 53, based on luminosity and nearness. X-ray emission from these objects was individually measured from the UCSD HEAO-1 all-sky survey in four energy bands between 13 keV to 160 keV. This data base consists of about 20 optical disk volumes. Net significance for the result was roughly two sigma, and a very hard spectral shape is indicated for the net spectrum of the surveyed galaxies. With the possibility of detection of the class, it was then felt worthwhile to examine fluxes from these sources in other archival data. This was performed with the HEAO-1 A2 data and the HEAO-2 (EINSTEIN) main archive and slew survey. Positive results were also obtained for the sample, but again at weak significance. With three independent measures of weak X-ray fluxes from nearby starburst galaxies, we wrote a letter to the Astrophysical Journal (enclosed) discussing these results and their likely significance, in particular, for the contribution to the cosmic diffuse x-ray background, perhaps as much as 25 percent.

  10. SPHEREx: Understanding the Origin and Evolution of Galaxies Through the Extragalactic Background Light

    Science.gov (United States)

    Zemcov, Michael; SPHEREx Science Team

    2018-01-01

    The near IR extragalactic background light (EBL) encodes the integrated light production over cosmic history, so traces the total emission from all galaxies along the line of sight up to the ancient first-light objects responsible for the epoch of reionization (EOR). The EBL can be constrained through measurements of anisotropies, taking advantage of the fact that extragalactic populations produce fluctuations with distinct spatial and spectral characteristics from local foregrounds. In particular, EBL anisotropies trace the underlying clustering of faint emission sources, such as stars, galaxies and accreting black holes present during the EOR, dwarf galaxies, and intra-halo light (IHL), all of which are components not readily detected in point source surveys. The fluctuation amplitude observed independently by a number of recent measurements exceeds that expected from the large-scale clustering of known galaxy populations, indicating the presence of a large integrated brightness from these faint and diffuse components. Improved large-area measurements covering the entire near-IR are required to constrain the possible models for the history of emission from stars back to the EOR.SPHEREx brings new capabilities to EBL fluctuation measurements, employing 96 spectral channels covering 0.75 to 5 microns with spectral resolving power R = 41 to 135 that enable SPHEREx to carry out a multi-frequency separation of the integrated light from galaxies, IHL, and EOR components using the rich auto- and cross-correlation information available from two 45 square degree surveys of the ecliptic poles. SPHEREx is an ideal intensity mapping machine, and has the sensitivity to disentangle the history of light production associated with EBL fluctuations. SPHEREx will search for an EOR component its to minimum required level through component separation and spectral fitting techniques optimized for the near-IR. In addition to broad-band intensity mapping that enhances and extends the

  11. Star Formation at z = 2.481 in the Lensed Galaxy SDSS J1110+6459. II. What is Missed at the Normal Resolution of the Hubble Space Telescope?

    Science.gov (United States)

    Rigby, J. R.; Johnson, T. L.; Sharon, K.; Whitaker, K.; Gladders, M. D.; Florian, M.; Lotz, J.; Bayliss, M.; Wuyts, E.

    2017-07-01

    For lensed galaxy SGAS J111020.0+645950.8 at redshift z = 2.481, which is magnified by a factor of 28 ± 8, we analyze the morphology of star formation, as traced by rest-frame ultraviolet emission, in both the highly magnified source plane and simulations of how this galaxy would appear without lensing magnification. Were this galaxy not lensed, but rather drawn from a Hubble Space Telescope deep field, we would conclude that almost all its star formation arises from an exponential disk (Sérsic index of 1.0 ± 0.4) with an effective radius of {r}e=2.7+/- 0.3 {kpc} measured from two-dimensional fitting to F606W using Galfit, and {r}e=1.9+/- 0.1 {kpc} measured by fitting a radial profile to F606W elliptical isophotes. At the normal spatial resolution of the deep fields, there is no sign of clumpy star formation within SGAS J111020.0+645950.8. However, the enhanced spatial resolution enabled by gravitational lensing tells a very different story; much of the star formation arises in two dozen clumps with sizes of r = 30-50 pc spread across the 7 kpc length of the galaxy. The color and spatial distribution of the diffuse component suggests that still-smaller clumps are unresolved. Despite this clumpy, messy morphology, the radial profile is still well-characterized by an exponential profile. In this lensed galaxy, stars are forming in complexes with sizes well below 100 pc such sizes are wholly unexplored by surveys of galaxy evolution at 1< z< 3.

  12. Spatially Resolved Analysis of the Interstellar Medium in the Cosmic Eye, a Lensed Lyman Break Galaxy at z=3.074

    Science.gov (United States)

    Ball, Catherine; Riechers, Dominik A.; Pavesi, Riccardo

    2018-01-01

    The [CII]/[NII] ratio combines the [CII] line, a tracer of photodissociation and HII regions emerging from the neutral and ionized phases of the interstellar medium (ISM), with [NII] emission, which only originates from the ionized ISM. In this, the [CII]/[NII] ratio can be used to separate the fractions of [CII] emission emerging from the different phases of the ISM. We present Atacama Large sub-Millimeter Array (ALMA) observations of the Cosmic Eye, a gravitationally lensed Lyman Break Galaxy (LBG). As an LBG, the Cosmic Eye represents a "normal" star forming galaxy in the z>2 universe. LBGs were host to the bulk of star formation during the peak epoch of star formation. Diagnosing star formation in these galaxies provides insight into the evolution of “normal” galaxies in a cosmic sense. The high magnification (30x) allows us to resolve the [CII] 158μm and the [NII] 205μm lines in detail, allowing for a position-resolved analysis of their ratio. We find variations of the line ratio across the galaxy, suggesting the galaxy’s internal structure affects this ratio. We consider the Cosmic Eye in the context of both higher redshift LBGs and local luminous and ultraluminous infrared galaxies, finding that the Cosmic Eye’s line ratio is similar to those of both higher- and lower- redshift galaxies. The Cosmic Eye’s global [CII]/[NII] ratio sits between two previous measurements of z>5 LBGs at low resolution, suggesting that the ratio may correlate more significantly with LFIR than with redshift in this epoch. Furthermore, the Cosmic Eye’s [CII]/[NII] ratio is similar to those of the nearby LIRG/ULIRGs, though we expect local [CII]/[NII] values to be lower due to their different metallicities and dust content. High-resolution studies like this one probe the evolution of [CII]/[NII] over cosmic time by examining the evolution of the ISM’s structure. With a better understanding of the [CII]/[NII] line ratio, we can more effectively use it as a probe of the

  13. On the Lack of Correlation Between Mg II 2796, 2803 Angstrom and Lyman alpha Emission in Lensed Star-Forming Galaxies

    Science.gov (United States)

    Rigby, Jane Rebecca; Bayliss, M. B.; Gladders, M. D.; Sharon, K.; Wuyts, E.; Dahle, H.

    2014-01-01

    We examine the Mg II 2796, 2803 Angstrom, Lyman alpha, and nebular line emission in five bright star-forming galaxies at 1.66 less than z less than 1.91 that have been gravitationally lensed by foreground galaxy clusters. All five galaxies show prominent Mg II emission and absorption in a P Cygni profile. We find no correlation between the equivalent widths of Mg II and Lyman alpha emission. The Mg II emission has a broader range of velocities than do the nebular emission line profiles; the Mg II emission is redshifted with respect to systemic by 100 to 200 km s(exp-1). When present, Lyman alpha is even more redshifted. The reddest components of Mg II and Lyman alpha emission have tails to 500-600 km s(exp-1), implying a strong outflow. The lack of correlation in the Mg II and Lyman alpha equivalent widths, the differing velocity profiles, and the high ratios of Mg II to nebular line fluxes together suggest that the bulk of Mg II emission does not ultimately arise as nebular line emission, but may instead be reprocessed stellar continuum emission.

  14. VizieR Online Data Catalog: Lensed z~6-8 galaxies behind CLASH clusters (Bradley+, 2014)

    Science.gov (United States)

    Bradley, L. D.; Zitrin, A.; Coe, D.; Bouwens, R.; Postman, M.; Balestra, I.; Grillo, C.; Monna, A.; Rosati, P.; Seitz, S.; Host, O.; Lemze, D.; Moustakas, J.; Moustakas, L. A.; Shu, X.; Zheng, W.; Broadhurst, T.; Carrasco, M.; Jouvel, S.; Koekemoer, A.; Medezinski, E.; Meneghetti, M.; Nonino, M.; Smit, R.; Umetsu, K.; Bartelmann, M.; Benitez, N.; Donahue, M.; Ford, H.; Infante, L.; Jimenez-Teja, Y.; Kelson, D.; Lahav, O.; Maoz, D.; Melchior, P.; Merten, J.; Molino, A.

    2017-04-01

    CLASH is a 524 orbit multi-cycle treasury program to observe 25 galaxy clusters to a total depth of 20 orbits each, incorporating archival HST data for our cluster sample whenever possible (Postman et al. 2012, J/ApJS/199/25). Each cluster is observed using WFC3/UVIS, ACS/WFC, and WFC3/IR to obtain imaging in 16 broadband filters spanning from 0.2 to 1.7 um (for the throughput curves of each filter, see Postman et al. 2012, J/ApJS/199/25 or Jouvel et al. 2014, J/A+A/562/A86). We used SExtractor version 2.5.0 (Bertin & Arnouts 1996A&AS..117..393B) in dual-image mode to perform object detection and photometry. For each of our 18 clusters, we constructed a detection image by performing an inverse-variance weighted sum of the images in all five WFC3/IR bands: Y105, J110, J125, JH140, and H160. The local background was measured within a rectangular annulus (default width 24 pixels) and sources were required to be detected at >1σ significance over a minimum area of nine contiguous pixels. (4 data files).

  15. The Ultraluminous X-Ray Source X-37 Is a Background Quasar in the Antennae Galaxies

    Science.gov (United States)

    Clark, D. M.; Christopher, M. H.; Eikenberry, S. S.; Brandl, B. R.; Wilson, J. C.; Carson, J. C.; Henderson, C. P.; Hayward, T. L.; Barry, D. J.; Ptak, A. F.; Colbert, E. J. M.

    2005-10-01

    In this Letter we report that a bright, X-ray source in the Antennae galaxies (NGC 4038/9), previously identified as an ultraluminous X-ray source (ULX), is in fact a background quasar. We identify an isolated infrared and optical counterpart within 0.3" +/- 0.5" of the X-ray source X-37. After acquiring an optical spectrum of its counterpart, we use the narrow [O III] and broad Hα emission lines to identify X-37 as a quasar at a redshift of z=0.26. Through a U, V, and Ks photometric analysis, we demonstrate that most of the observable light along this line of sight is from the quasar. We discuss the implications of this discovery and the importance of acquiring spectra for optical and IR counterparts to ULXs.

  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. Galaxies

    International Nuclear Information System (INIS)

    1987-01-01

    The size and nature of any large-scale anisotropy in the three-dimensional distribution of galaxies is still little understood. Recent studies have indicated that large fluctuations in the matter distribution on a scale from tens up to several hundreds of megaparsecs may exist. Work at the South African Astronomical Observatory (SAAO) in recent years has made major contributions to studies of the large scale distribution of galaxies, as well as to solving the problems of the galactic and extragalactic distance scale. Other studies of galaxies undertaken at SAAO include: quasars in the fields of nearby galaxies; dwarf irregular galaxies; IRAS galaxies; Seyfert galaxies; 'hot spot' galaxies; supernovae in NGC 5128 and NGC 1559 and superclusters. 4 figs

  18. Galaxies

    International Nuclear Information System (INIS)

    1989-01-01

    In studies of the large scale structure of the universe there is a continuing need for extensive galaxy redshift determinations. Optically selected redshift surveys are of particular importance, since flux-limited samples record much higher space densities of galaxies than samples of similar size selected in other wavebands. A considerable amount of the South African Astronomical Observatory (SAAO) observing time is currently being devoted to carrying out a large southern galaxy redshift survey. A recently completed study, the Durham-SAAO redshift survey suggests that the mean density of matter is well below the critical limit for a closed universe and also that the universe may be homogenous at very large scales. Other research conducted by the SAAO include studies on: the distribution of galaxies; Seyfert galaxies; starburst and IRAS galaxies; interacting and compact galaxies; a re-evaluation of the Cepheid distance to NGC 300, and a search for quasars behind galaxies. 1 fig

  19. 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.

  20. The Sloan Lens ACS Survey. I. A Large Spectroscopically Selected Sample of Massive Early-Type Lens Galaxies

    Science.gov (United States)

    Bolton, Adam S.; Burles, Scott; Koopmans, Leon V. E.; Treu, Tommaso; Moustakas, Leonidas A.

    2006-01-01

    The Sloan Lens ACS (SLACS) Survey is an efficient Hubble Space Telescope (HST) Snapshot imaging survey for new galaxy-scale strong gravitational lenses. The targeted lens candidates are selected spectroscopically from the Sloan Digital Sky Survey (SDSS) database of galaxy spectra for having multiple nebular emission lines at a redshift significantly higher than that of the SDSS target galaxy. The SLACS survey is optimized to detect bright early-type lens galaxies with faint lensed sources in order to increase the sample of known gravitational lenses suitable for detailed lensing, photometric, and dynamical modeling. In this paper, the first in a series on the current results of our HST Cycle 13 imaging survey, we present a catalog of 19 newly discovered gravitational lenses, along with nine other observed candidate systems that are either possible lenses, nonlenses, or nondetections. The survey efficiency is thus >=68%. We also present Gemini 8 m and Magellan 6.5 m integral-field spectroscopic data for nine of the SLACS targets, which further support the lensing interpretation. A new method for the effective subtraction of foreground galaxy images to reveal faint background features is presented. We show that the SLACS lens galaxies have colors and ellipticities typical of the spectroscopic parent sample from which they are drawn (SDSS luminous red galaxies and quiescent MAIN sample galaxies), but are somewhat brighter and more centrally concentrated. Several explanations for the latter bias are suggested. The SLACS survey provides the first statistically significant and homogeneously selected sample of bright early-type lens galaxies, furnishing a powerful probe of the structure of early-type galaxies within the half-light radius. The high confirmation rate of lenses in the SLACS survey suggests consideration of spectroscopic lens discovery as an explicit science goal of future spectroscopic galaxy surveys.

  1. The GeV Excess Shining Through: Background Systematics for the Inner Galaxy Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Calore, Francesca; Cholis, Ilias; Weniger, Christoph

    2015-02-10

    Recently, a spatially extended excess of gamma rays collected by the Fermi-LAT from the inner region of the Milky Way has been detected by different groups and with increasingly sophisticated techniques. Yet, any final conclusion about the morphology and spectral properties of such an extended diffuse emission are subject to a number of potentially critical uncertainties, related to the high density of cosmic rays, gas, magnetic fields and abundance of point sources. We will present a thorough study of the systematic uncertainties related to the modelling of diffuse background and to the propagation of cosmic rays in the inner part of our Galaxy. We will test a large set of models for the Galactic diffuse emission, generated by varying the propagation parameters within extreme conditions. By using those models in the fit of Fermi-LAT data as Galactic foreground, we will show that the gamma-ray excess survives and we will quantify the uncertainties on the excess emission morphology and energy spectrum.

  2. The kinematical structure of gravitationally lensed arcs

    NARCIS (Netherlands)

    Moller, O; Noordermeer, E

    2006-01-01

    In this paper, the expected properties of the velocity fields of strongly lensed arcs behind galaxy clusters are investigated. The velocity profile along typical lensed arcs is determined by ray-tracing light rays from a model source galaxy through parametric cluster toy models consisting of

  3. Star-forming galaxies significantly contribute to the isotropic gamma-ray background

    Science.gov (United States)

    Linden, Tim

    2017-10-01

    The origin of the isotropic gamma-ray background (IGRB)—the portion of the extragalactic gamma-ray sky that is not resolvable into individual point sources—provides a powerful probe into the evolution of the high-energy Universe. Star-forming galaxies (SFGs) are among the most likely contributors to the IGRB, though their contribution is difficult to constrain because their flux distribution is dominated by numerous faint sources. We produce a novel joint-likelihood analysis of the γ -ray emission from 584 SFGs, utilizing advanced statistical techniques to compare the distribution of low-significance excesses against the non-Poissonian γ -ray background fluctuations. We first examine the theoretically well-motivated relationship between the far-IR and γ -ray luminosities of SFGs, utilizing a model where the γ -ray luminosity is given by log10 (Lγ/(erg s-1 ))=αlog10 (LIR /(10 10L⊙))+β . We calculate best-fit parameters α =1.18 ±0.15 , β =38.49 ±0.24 , with a log-normal dispersion in this relationship given by σ =0.39 ±0.12 . The best-fit values of α and β are consistent with previous studies. We find a larger dispersion in the far-IR to γ -ray correlation than previous studies. This dispersion is significant at the level of 5.7 σ . These results imply that SFGs significantly contribute to the IGRB, producing between 61.0-18.3+30.2% of the total IGRB intensity above an energy of 1 GeV. Along with recent works, this strongly indicates that multiple source classes provide comparable contributions to the IGRB intensity. We discuss the implication of these results for the interpretation of the IceCube neutrinos.

  4. GALAXY CLUSTERS IN THE LINE OF SIGHT TO BACKGROUND QUASARS. III. MULTI-OBJECT SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, H.; Barrientos, L. F.; Padilla, N.; Lacerna, I. [Instituto de Astrofisica, Pontificia Universidad Catolica de Chile, Avenida Vicuna Mackenna 4860, Santiago (Chile); Lopez, S.; Lira, P.; Maureira, M. J. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Gilbank, D. G. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935 (South Africa); Ellingson, E. [Center for Astrophysics and Space Astronomy, University of Colorado at Boulder, Campus Box 389, Boulder, CO 80309-0389 (United States); Gladders, M. D. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Yee, H. K. C., E-mail: barrientos@astro.puc.cl [Department of Astronomy and Astrophysics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 3H8 (Canada)

    2013-09-01

    We present Gemini/GMOS-S multi-object spectroscopy of 31 galaxy cluster candidates at redshifts between 0.2 and 1.0 and centered on QSO sight lines taken from Lopez et al. The targets were selected based on the presence of an intervening Mg II absorption system at a similar redshift to that of a galaxy cluster candidate lying at a projected distance <2 h{sub 71}{sup -1} Mpc from the QSO sight line (a {sup p}hotometric hit{sup )}. The absorption systems span rest-frame equivalent widths between 0.015 and 2.028 A. Our aim was three-fold: (1) to identify the absorbing galaxies and determine their impact parameters, (2) to confirm the galaxy cluster candidates in the vicinity of each quasar sightline, and (3) to determine whether the absorbing galaxies reside in galaxy clusters. In this way, we are able to characterize the absorption systems associated with cluster members. Our main findings are as follows. (1) We identified 10 out of 24 absorbing galaxies with redshifts between 0.2509 {<=} z{sub gal} {<=} 1.0955, up to an impact parameter of 142 h{sub 71}{sup -1} kpc and a maximum velocity difference of 280 km s{sup -1}. (2) We spectroscopically confirmed 20 out of 31 cluster/group candidates, with most of the confirmed clusters/groups at z < 0.7. This relatively low efficiency results from the fact that we centered our observations on the QSO location, and thus occasionally some of the cluster centers were outside the instrument field of view. (3) Following from the results above, we spectroscopically confirmed of 10 out of 14 photometric hits within {approx}650 km s{sup -1} from galaxy clusters/groups, in addition to two new ones related to galaxy group environments. These numbers imply efficiencies of 71% in finding such systems with MOS spectroscopy. This is a remarkable result since we defined a photometric hit as those cluster-absorber pairs having a redshift difference {Delta}z = 0.1. The general population of our confirmed absorbing galaxies have luminosities

  5. Predicting weak lensing statistics from halo mass reconstructions - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Everett, Spencer [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-20

    As dark matter does not absorb or emit light, its distribution in the universe must be inferred through indirect effects such as the gravitational lensing of distant galaxies. While most sources are only weakly lensed, the systematic alignment of background galaxies around a foreground lens can constrain the mass of the lens which is largely in the form of dark matter. In this paper, I have implemented a framework to reconstruct all of the mass along lines of sight using a best-case dark matter halo model in which the halo mass is known. This framework is then used to make predictions of the weak lensing of 3,240 generated source galaxies through a 324 arcmin² field of the Millennium Simulation. The lensed source ellipticities are characterized by the ellipticity-ellipticity and galaxy-mass correlation functions and compared to the same statistic for the intrinsic and ray-traced ellipticities. In the ellipticity-ellipticity correlation function, I and that the framework systematically under predicts the shear power by an average factor of 2.2 and fails to capture correlation from dark matter structure at scales larger than 1 arcminute. The model predicted galaxy-mass correlation function is in agreement with the ray-traced statistic from scales 0.2 to 0.7 arcminutes, but systematically underpredicts shear power at scales larger than 0.7 arcminutes by an average factor of 1.2. Optimization of the framework code has reduced the mean CPU time per lensing prediction by 70% to 24 ± 5 ms. Physical and computational shortcomings of the framework are discussed, as well as potential improvements for upcoming work.

  6. Dark Energy Survey Year 1 Results: The Impact of Galaxy Neighbours on Weak Lensing Cosmology with im3shape

    Energy Technology Data Exchange (ETDEWEB)

    Samuroff, S.; et al.

    2017-08-04

    We use a suite of simulated images based on Year 1 of the Dark Energy Survey to explore the impact of galaxy neighbours on shape measurement and shear cosmology. The hoopoe image simulations include realistic blending, galaxy positions, and spatial variations in depth and PSF properties. Using the im3shape maximum-likelihood shape measurement code, we identify four mechanisms by which neighbours can have a non-negligible influence on shear estimation. These effects, if ignored, would contribute a net multiplicative bias of $m \\sim 0.03 - 0.09$ in the DES Y1 im3shape catalogue, though the precise impact will be dependent on both the measurement code and the selection cuts applied. This can be reduced to percentage level or less by removing objects with close neighbours, at a cost to the effective number density of galaxies $n_\\mathrm{eff}$ of 30%. We use the cosmological inference pipeline of DES Y1 to explore the cosmological implications of neighbour bias and show that omitting blending from the calibration simulation for DES Y1 would bias the inferred clustering amplitude $S_8\\equiv \\sigma_8 (\\Omega _\\mathrm{m} /0.3)^{0.5}$ by $2 \\sigma$ towards low values. Finally, we use the hoopoe simulations to test the effect of neighbour-induced spatial correlations in the multiplicative bias. We find the impact on the recovered $S_8$ of ignoring such correlations to be subdominant to statistical error at the current level of precision.

  7. Reconstructing the lensing mass in the Universe from photometric catalogue data

    NARCIS (Netherlands)

    Collett, Thomas E.; Marshall, Philip J.; Auger, Matthew W.; Hilbert, Stefan; Suyu, Sherry H.; Greene, Zachary; Treu, Tommaso; Fassnacht, Christopher D.; Koopmans, Leon V. E.; Bradac, Marusa; Blandford, Roger D.

    2013-01-01

    High precision cosmological distance measurements towards individual objects such as time delay gravitational lenses or Type Ia supernovae are affected by weak lensing perturbations by galaxies and groups along the line of sight. In time delay gravitational lenses, 'external convergence',

  8. 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)

  9. Gravitational lenses and. cosmological evolution

    Science.gov (United States)

    Peacock, J. A.

    1982-06-01

    The effect of gravitational lensing on the apparent evolution of extragalactic radio sources is investigated. Models for a lens population consisting of galaxies and clusters of galaxies are constructed 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 10-20 per cent relative to a homogeneous universe, flux conservation implies that de-amplification is as common as amplification. The effect 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 sample Lensing effects may be of greater importance for optically selected quasar where lenses of mass as low as ˜10-4 Msun can cause large amplifications.

  10. A DIRECT MEASUREMENT OF THE LINEAR BIAS OF MID-INFRARED-SELECTED QUASARS AT z ≈ 1 USING COSMIC MICROWAVE BACKGROUND LENSING

    Energy Technology Data Exchange (ETDEWEB)

    Geach, J. E. [Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield, AL10 9AB (United Kingdom); Hickox, R. C.; Hainline, K. N. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States); Bleem, L. E.; Benson, B. A.; Bhattacharya, S.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Brodwin, M. [Department of Physics and Astronomy, University of Missouri, Kansas City, MO 64110 (United States); Holder, G. P.; De Haan, T.; Dobbs, M. A.; Dudley, J. [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada); Aird, K. A. [University of Chicago, Chicago, IL 60637 (United States); Cho, H.-M. [NIST Quantum Devices Group, Boulder, CO 80305 (United States); George, E. M.; Holzapfel, W. L. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Halverson, N. W., E-mail: j.geach@herts.ac.uk [Department of Astrophysical and Planetary Sciences and Department of Physics, University of Colorado, Boulder, CO 80309 (United States); and others

    2013-10-20

    We measure the cross-power spectrum of the projected mass density as traced by the convergence of the cosmic microwave background lensing field from the South Pole Telescope (SPT) and a sample of Type 1 and 2 (unobscured and obscured) quasars at (z) ∼ 1 selected with the Wide-field Infrared Survey Explorer, over 2500 deg{sup 2}. The cross-power spectrum is detected at ≈7σ, and we measure a linear bias b = 1.61 ± 0.22, consistent with clustering analyses. Using an independent lensing map, derived from Planck observations, to measure the cross-spectrum, we find excellent agreement with the SPT analysis. The bias of the combined sample of Type 1 and 2 quasars determined in this work is similar to that previously determined for Type 1 quasars alone; we conclude that obscured and unobscured quasars trace the matter field in a similar way. This result has implications for our understanding of quasar unification and evolution schemes.

  11. Dark Energy Survey Year 1 results: the impact of galaxy neighbours on weak lensing cosmology with IM3SHAPE

    Science.gov (United States)

    Samuroff, S.; Bridle, S. L.; Zuntz, J.; Troxel, M. A.; Gruen, D.; Rollins, R. P.; Bernstein, G. M.; Eifler, T. F.; Huff, E. M.; Kacprzak, T.; Krause, E.; MacCrann, N.; Abdalla, F. B.; Allam, S.; Annis, J.; Bechtol, K.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Crocce, M.; D'Andrea, C. B.; da Costa, L. N.; Davis, C.; Desai, S.; Doel, P.; Fausti Neto, A.; Flaugher, B.; Fosalba, P.; Frieman, J.; García-Bellido, J.; Gerdes, D. W.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; Honscheid, K.; James, D. J.; Jarvis, M.; Jeltema, T.; Kirk, D.; Kuehn, K.; Kuhlmann, S.; Li, T. S.; Lima, M.; Maia, M. A. G.; March, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Menanteau, F.; Miquel, R.; Nord, B.; Ogando, R. L. C.; Plazas, A. A.; Roodman, A.; Sanchez, E.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, M.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Thomas, D.; Tucker, D. L.; DES Collaboration

    2018-04-01

    We use a suite of simulated images based on Year 1 of the Dark Energy Survey to explore the impact of galaxy neighbours on shape measurement and shear cosmology. The HOOPOE image simulations include realistic blending, galaxy positions, and spatial variations in depth and point spread function properties. Using the IM3SHAPE maximum-likelihood shape measurement code, we identify four mechanisms by which neighbours can have a non-negligible influence on shear estimation. These effects, if ignored, would contribute a net multiplicative bias of m ˜ 0.03-0.09 in the Year One of the Dark Energy Survey (DES Y1) IM3SHAPE catalogue, though the precise impact will be dependent on both the measurement code and the selection cuts applied. This can be reduced to percentage level or less by removing objects with close neighbours, at a cost to the effective number density of galaxies neff of 30 per cent. We use the cosmological inference pipeline of DES Y1 to explore the cosmological implications of neighbour bias and show that omitting blending from the calibration simulation for DES Y1 would bias the inferred clustering amplitude S8 ≡ σ8(Ωm/0.3)0.5 by 2σ towards low values. Finally, we use the HOOPOE simulations to test the effect of neighbour-induced spatial correlations in the multiplicative bias. We find the impact on the recovered S8 of ignoring such correlations to be subdominant to statistical error at the current level of precision.

  12. 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

  13. Constraining Dark Energy with X-ray Galaxy Clusters, Supernovae and the Cosmic Microwave Background

    International Nuclear Information System (INIS)

    Rapetti, D

    2005-01-01

    We present new constraints on the evolution of dark energy from an analysis of Cosmic Microwave Background, supernova and X-ray galaxy cluster data. Our analysis employs a minimum of priors and exploits the complementary nature of these data sets. We examine a series of dark energy models with up to three free parameters: the current dark energy equation of state w 0 , the early time equation of state w et and the scale factor at transition, a t . From a combined analysis of all three data sets, assuming a constant equation of state and that the Universe is flat, we measure w 0 = 1.05 -0.12 +0.10 . Including w et as a free parameter and allowing the transition scale factor to vary over the range 0.5 t 0 = -1.27 -0.39 +0.33 and w et = -0.66 -0.62 +0.44 . We find no significant evidence for evolution in the dark energy equation of state parameter with redshift. Marginal hints of evolution in the supernovae data become less significant when the cluster constraints are also included in the analysis. The complementary nature of the data sets leads to a tight constraint on the mean matter density, (Omega) m and alleviates a number of other parameter degeneracies, including that between the scalar spectral index n s , the physical baryon density (Omega) b h 2 and the optical depth τ. This complementary nature also allows us to examine models in which we drop the prior on the curvature. For non-flat models with a constant equation of state, we measure w 0 = -1.09 -0.15 +0.12 and obtain a tight constraint on the current dark energy density, (Omega) de = 0.70 ± 0.03. For dark energy models other than a cosmological constant, energy-momentum conservation requires the inclusion of spatial perturbations in the dark energy component. Our analysis includes such perturbations, assuming a sound speed c s 2 = 1 in the dark energy fluid as expected for Quintessence scenarios. For our most general dark energy model, not including such perturbations would lead to spurious constraints

  14. High-energy gamma-ray and neutrino backgrounds from clusters of galaxies and radio constraints

    NARCIS (Netherlands)

    Zandanel, F.; Tamborra, I.; Gabici, S.; Ando, S.

    2015-01-01

    Cosmic-ray protons accumulate for cosmological times in clusters of galaxies because their typical radiative and diffusive escape times are longer than the Hubble time. Their hadronic interactions with protons of the intra-cluster medium generate secondary electrons, gamma rays, and neutrinos. In

  15. 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

  16. Galaxy Clustering and Merging

    Science.gov (United States)

    Wen, Z. L.

    2011-09-01

    Cosmic structure formation and galaxy evolution are important subjects in astrophysics. The thesis consists of two parts: (1) identification of galaxy clusters and studies of their properties; (2) identification of the mergers of luminous early-type galaxies and gravitational waves (GWs). Most of the galaxy clusters in the previous catalogs have redshifts z≤0.3 with richnesses not well determined. Using the photometric redshifts of galaxies from the Sixth Data Release of Sloan Digital Sky Survey (SDSS DR6), we identify 39716 clusters in the redshift range of 0.05contamination rate and the completeness of member galaxies are found to be ˜20% and ∼90%, respectively. Monte Carlo simulations show that the cluster detection rate is larger than 90% for the massive (M_{200}>2×10^{14} M_{⊙}) clusters with z≤0.42. The false detection rate is ˜5%. We obtain the richness, the summed luminosity and the gross galaxy number. They are tightly correlated with the X-ray luminosity and the temperature of clusters. The cluster mass is also found to be tightly related to the richness and summed luminosity in the form of M_{200}∝ R^{1.90±0.04} and M_{200}∝ L_r^{1.64±0.03}, respectively. In addition, 790 new candidates of X-ray clusters are found by cross-identification of our clusters with the unidentified source list of the ROSAT X-ray survey. By visual inspections of the detected clusters, we recognize 13 gravitational lensing candidates. Among all the candidates, four can be sure strong lensing systems even without further spectroscopic identification, five are more probable and four are possible lenses. In the second part, we discuss the merger rates of luminous early-type galaxies and GWs from the mergers of supermassive black holes (SMBHs). The merger rates of massive galaxies in the local universe are still not clear so far. We select a large sample (1209) of close pairs of galaxies with projected separations 7 kpc

  17. Maximal lens bounds on QSO-galaxy association

    International Nuclear Information System (INIS)

    Kovner, I.

    1989-01-01

    The maximal possible enhancement of QSO number counts that can be produced by any ensemble of lenses which conserve brightness and in which the magnification probability is negligibly correlated with the intrinsic QSO flux is obtained. Under the assumption of the Boyle et al. (1988) number-magnitude relation for the QSOs unaffected by lenses, the theory is applied to the QSO-galaxy association sample of Webster et al. (1988). The results suggest that the background QSOs of Webster et al. may be appreciably affected by lensing. 17 refs

  18. A measurement of CMB cluster lensing with SPT and DES year 1 data

    Science.gov (United States)

    Baxter, E. J.; Raghunathan, S.; Crawford, T. M.; Fosalba, P.; Hou, Z.; Holder, G. P.; Omori, Y.; Patil, S.; Rozo, E.; Abbott, T. M. C.; Annis, J.; Aylor, K.; Benoit-Lévy, A.; Benson, B. A.; Bertin, E.; Bleem, L.; Buckley-Geer, E.; Burke, D. L.; Carlstrom, J.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Chang, C. L.; Cho, H.-M.; Crites, A. T.; Crocce, M.; Cunha, C. E.; da Costa, L. N.; D'Andrea, C. B.; Davis, C.; de Haan, T.; Desai, S.; Dietrich, J. P.; Dobbs, M. A.; Dodelson, S.; Doel, P.; Drlica-Wagner, A.; Estrada, J.; Everett, W. B.; Fausti Neto, A.; Flaugher, B.; Frieman, J.; García-Bellido, J.; George, E. M.; Gaztanaga, E.; Giannantonio, T.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; Halverson, N. W.; Harrington, N. L.; Hartley, W. G.; Holzapfel, W. L.; Honscheid, K.; Hrubes, J. D.; Jain, B.; James, D. J.; Jarvis, M.; Jeltema, T.; Knox, L.; Krause, E.; Kuehn, K.; Kuhlmann, S.; Kuropatkin, N.; Lahav, O.; Lee, A. T.; Leitch, E. M.; Li, T. S.; Lima, M.; Luong-Van, D.; Manzotti, A.; March, M.; Marrone, D. P.; Marshall, J. L.; Martini, P.; McMahon, J. J.; Melchior, P.; Menanteau, F.; Meyer, S. S.; Miller, C. J.; Miquel, R.; Mocanu, L. M.; Mohr, J. J.; Natoli, T.; Nord, B.; Ogando, R. L. C.; Padin, S.; Plazas, A. A.; Pryke, C.; Rapetti, D.; Reichardt, C. L.; Romer, A. K.; Roodman, A.; Ruhl, J. E.; Rykoff, E.; Sako, M.; Sanchez, E.; Sayre, J. T.; Scarpine, V.; Schaffer, K. K.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Shirokoff, E.; Smith, M.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Staniszewski, Z.; Stark, A.; Story, K.; Suchyta, E.; Tarle, G.; Thomas, D.; Troxel, M. A.; Vanderlinde, K.; Vieira, J. D.; Walker, A. R.; Williamson, R.; Zhang, Y.; Zuntz, J.

    2018-05-01

    Clusters of galaxies gravitationally lens the cosmic microwave background (CMB) radiation, resulting in a distinct imprint in the CMB on arcminute scales. Measurement of this effect offers a promising way to constrain the masses of galaxy clusters, particularly those at high redshift. We use CMB maps from the South Pole Telescope Sunyaev-Zel'dovich (SZ) survey to measure the CMB lensing signal around galaxy clusters identified in optical imaging from first year observations of the Dark Energy Survey. The cluster catalogue used in this analysis contains 3697 members with mean redshift of \\bar{z} = 0.45. We detect lensing of the CMB by the galaxy clusters at 8.1σ significance. Using the measured lensing signal, we constrain the amplitude of the relation between cluster mass and optical richness to roughly 17 {per cent} precision, finding good agreement with recent constraints obtained with galaxy lensing. The error budget is dominated by statistical noise but includes significant contributions from systematic biases due to the thermal SZ effect and cluster miscentring.

  19. A Measurement of CMB Cluster Lensing with SPT and DES Year 1 Data

    Science.gov (United States)

    Baxter, E. J.; Raghunathan, S.; Crawford, T. M.; Fosalba, P.; Hou, Z.; Holder, G. P.; Omori, Y.; Patil, S.; Rozo, E.; Abbott, T. M. C.; Annis, J.; Aylor, K.; Benoit-Lévy, A.; Benson, B. A.; Bertin, E.; Bleem, L.; Buckley-Geer, E.; Burke, D. L.; Carlstrom, J.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Chang, C. L.; Cho, H.-M.; Crites, A. T.; Crocce, M.; Cunha, C. E.; da Costa, L. N.; D'Andrea, C. B.; Davis, C.; de Haan, T.; Desai, S.; Dietrich, J. P.; Dobbs, M. A.; Dodelson, S.; Doel, P.; Drlica-Wagner, A.; Estrada, J.; Everett, W. B.; Fausti Neto, A.; Flaugher, B.; Frieman, J.; García-Bellido, J.; George, E. M.; Gaztanaga, E.; Giannantonio, T.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; Halverson, N. W.; Harrington, N. L.; Hartley, W. G.; Holzapfel, W. L.; Honscheid, K.; Hrubes, J. D.; Jain, B.; James, D. J.; Jarvis, M.; Jeltema, T.; Knox, L.; Krause, E.; Kuehn, K.; Kuhlmann, S.; Kuropatkin, N.; Lahav, O.; Lee, A. T.; Leitch, E. M.; Li, T. S.; Lima, M.; Luong-Van, D.; Manzotti, A.; March, M.; Marrone, D. P.; Marshall, J. L.; Martini, P.; McMahon, J. J.; Melchior, P.; Menanteau, F.; Meyer, S. S.; Miller, C. J.; Miquel, R.; Mocanu, L. M.; Mohr, J. J.; Natoli, T.; Nord, B.; Ogando, R. L. C.; Padin, S.; Plazas, A. A.; Pryke, C.; Rapetti, D.; Reichardt, C. L.; Romer, A. K.; Roodman, A.; Ruhl, J. E.; Rykoff, E.; Sako, M.; Sanchez, E.; Sayre, J. T.; Scarpine, V.; Schaffer, K. K.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Shirokoff, E.; Smith, M.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Staniszewski, Z.; Stark, A.; Story, K.; Suchyta, E.; Tarle, G.; Thomas, D.; Troxel, M. A.; Vanderlinde, K.; Vieira, J. D.; Walker, A. R.; Williamson, R.; Zhang, Y.; Zuntz, J.

    2018-02-01

    Clusters of galaxies gravitationally lens the cosmic microwave background (CMB) radiation, resulting in a distinct imprint in the CMB on arcminute scales. Measurement of this effect offers a promising way to constrain the masses of galaxy clusters, particularly those at high redshift. We use CMB maps from the South Pole Telescope Sunyaev-Zel'dovich (SZ) survey to measure the CMB lensing signal around galaxy clusters identified in optical imaging from first year observations of the Dark Energy Survey. The cluster catalog used in this analysis contains 3697 members with mean redshift of \\bar{z} = 0.45. We detect lensing of the CMB by the galaxy clusters at 8.1σ significance. Using the measured lensing signal, we constrain the amplitude of the relation between cluster mass and optical richness to roughly 17% precision, finding good agreement with recent constraints obtained with galaxy lensing. The error budget is dominated by statistical noise but includes significant contributions from systematic biases due to the thermal SZ effect and cluster miscentering.

  20. Cross-correlation of gravitational lensing from DES Science Verification data with SPT and Planck lensing

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, D.; Omori, Y.; Benoit-Lévy, A.; Cawthon, R.; Chang, C.; Larsen, P.; Amara, A.; Bacon, D.; Crawford, T. M.; Dodelson, S.; Fosalba, P.; Giannantonio, T.; Holder, G.; Jain, B.; Kacprzak, T.; Lahav, O.; MacCrann, N.; Nicola, A.; Refregier, A.; Sheldon, E.; Story, K. T.; Troxel, M. A.; Vieira, J. D.; Vikram, V.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Becker, M. R.; Benson, B. A.; Bernstein, G. M.; Bernstein, R. A.; Bleem, L. E.; Bonnett, C.; Bridle, S. L.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carlstrom, J. E.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Crocce, M.; Cunha, C. E.; D' Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Jarvis, M.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lima, M.; March, M.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Reichardt, C. L.; Roodman, A.; Rozo, E.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Simard, G.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Wechsler, R. H.; Weller, J.

    2016-03-10

    We measure the cross-correlation between weak lensing of galaxy images and of the cosmic microwave background (CMB). The effects of gravitational lensing on different sources will be correlated if the lensing is caused by the same mass fluctuations. We use galaxy shape measurements from 139 deg(2) of the Dark Energy Survey (DES) Science Verification data and overlapping CMB lensing from the South Pole Telescope (SPT) and Planck. The DES source galaxies have a median redshift of z(med) similar to 0.7, while the CMB lensing kernel is broad and peaks at z similar to 2. The resulting cross-correlation is maximally sensitive to mass fluctuations at z similar to 0.44. Assuming the Planck 2015 best-fitting cosmology, the amplitude of the DESxSPT cross-power is found to be A(SPT) = 0.88 +/- 0.30 and that from DESxPlanck to be A(Planck) = 0.86 +/- 0.39, where A = 1 corresponds to the theoretical prediction. These are consistent with the expected signal and correspond to significances of 2.9 sigma and 2.2 sigma, respectively. We demonstrate that our results are robust to a number of important systematic effects including the shear measurement method, estimator choice, photo-z uncertainty and CMB lensing systematics. We calculate a value of A = 1.08 +/- 0.36 for DESxSPT when we correct the observations with a simple intrinsic alignment model. With three measurements of this cross-correlation now existing in the literature, there is not yet reliable evidence for any deviation from the expected LCDM level of cross-correlation. We provide forecasts for the expected signal-to-noise ratio of the combination of the five-year DES survey and SPT-3G.

  1. Evidence for Galaxy Dynamics Tracing Background Cosmology Below the de Sitter Scale of Acceleration

    Science.gov (United States)

    Van Putten, Maurice H.

    2018-01-01

    Galaxy dynamics probes weak gravity at accelerations below the de Sitter scale of acceleration $a_{dS}=cH$, where $c$ is the velocity of light and $H$ is the Hubble parameter. Low and high redshift galaxies hereby offer a novel probe of weak gravity in an evolving cosmology, satisfying $H(z)=H_0\\sqrt{1+\\omega_m(6z+12z^2+12z^3+6z^4+(6/5)z^5)}/(1+z)$ with baryonic matter content $\\omega_m=0.2808\\pm0.028$ sans tension to $H_0$ in surveys of the Local Universe. Galaxy rotation curves show anomalous galaxy dynamics in weak gravity $a_Ninertia from entanglement entropy, that introduces a $C^0$ onset across $a_N=a_{dS}$ with asymptotic behavior described by a Milgrom parameter satisfying $a_0=\\omega_0/2\\pi$, where $\\omega_0=\\sqrt{1-q}H$ is a fundamental eigenfrequency of the cosmological horizon. Extending an earlier confrontation with data covering $0.003\\lesssim a_N/a_{dS}\\lesssim1$ at redshift $z\\sim0$ in Lellie et al. (2016), the modest anomalous behavior in the Genzel et al. sample at redshifts $0.854\\le z\\le 2.282$ is found to be mostly due to clustering $0.36\\lesssim a_N/a_{dS}\\lesssim1$ close to the $C^0$ onset to weak gravity and an increase of up to 65\\% in $a_0$.

  2. 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.

  3. The LABOCA/ACT Survey of Clusters at All Redshifts: Multiwavelength Analysis of Background Submillimeter Galaxies

    Science.gov (United States)

    Aguirre, Paula; Lindner, Robert R.; Baker, Andrew J.; Bond, J. Richard; Dünner, Rolando; Galaz, Gaspar; Gallardo, Patricio; Hilton, Matt; Hughes, John P.; Infante, Leopoldo; Lima, Marcos; Menten, Karl M.; Sievers, Jonathan; Weiss, Axel; Wollack, Edward J.

    2018-03-01

    We present a multiwavelength analysis of 48 submillimeter galaxies (SMGs) detected in the Large APEX Bolometer Camera/Atacama Cosmology Telescope (ACT) Survey of Clusters at All Redshifts, LASCAR, which acquired new 870 μm and Australia Telescope Compact Array 2.1 GHz observations of 10 galaxy clusters detected through their Sunyaev–Zel’dovich effect (SZE) signal by the ACT. Far-infrared observations were also conducted with the Photodetector Array Camera and Spectrometer (100/160 μm) and SPIRE (250/350/500 μm) instruments on Herschel for sample subsets of five and six clusters. LASCAR 870 μm maps were reduced using a multiscale iterative pipeline that removes the SZE increment signal, yielding point-source sensitivities of σ ∼ 2 mJy beam‑1. We detect in total 49 sources at the 4σ level and conduct a detailed multiwavelength analysis considering our new radio and far-IR observations plus existing near-IR and optical data. One source is identified as a foreground galaxy, 28 SMGs are matched to single radio sources, four have double radio counterparts, and 16 are undetected at 2.1 GHz but tentatively associated in some cases to near-IR/optical sources. We estimate photometric redshifts for 34 sources with secure (25) and tentative (9) matches at different wavelengths, obtaining a median z={2.8}-1.7+2.1. Compared to previous results for single-dish surveys, our redshift distribution has a comparatively larger fraction of sources at z > 3, and the high-redshift tail is more extended. This is consistent with millimeter spectroscopic confirmation of a growing number of high-z SMGs and relevant for testing of cosmological models. Analytical lens modeling is applied to estimate magnification factors for 42 SMGs at clustercentric radii >1.‧2 with the demagnified flux densities and source-plane areas, we obtain integral number counts that agree with previous submillimeter surveys.

  4. The Cluster Lens SDSS 1004+4112: Constraining World Models With its Multiply-Imaged Quasar and Galaxies

    Science.gov (United States)

    Kochanek, C.

    2005-07-01

    We will use deep ACS imaging of the giant {15 arcsec} four-image z_s=1.734 lensed quasar SDSS 1004+4112, and its z_l=0.68 lensing galaxy cluster, to identify many additional multiply-imaged background galaxies. Combining the existing single orbit ACS I-band image with ground based data, we have definitely identified two multiply imaged galaxies with estimated redshifts of 2.6 and 4.3, about 15 probable images of background galaxies, and a point source in the core of the central cD galaxy, which is likely to be the faint, fifth image of the quasar. The new data will provide accurate photometric redshifts, confirm that the candidate fifth image has the same spectral energy distribution as the other quasar images, allow secure identification of additional multiply-lensed galaxies for improving the mass model, and permit identification of faint cluster members. Due to the high lens redshift and the broad redshift distribution of the lensed background sources, we should be able to use the source-redshift scaling of the Einstein radius that depends on {d_ls/d_os}, to derive a direct, geometric estimate of Omega_Lambda. The deeper images will also allow a weak lensing analysis to extend the mass distribution to larger radii. Unlike any other cluster lenses, the time delay between the lensed quasar images {already measured for the A-B images, and measurable for the others over the next few years}, breaks the so-called kappa-degeneracies that complicate weak-lensing analyses.

  5. BIASED DARK ENERGY CONSTRAINTS FROM NEGLECTING REDUCED SHEAR IN WEAK-LENSING SURVEYS

    International Nuclear Information System (INIS)

    Shapiro, Charles

    2009-01-01

    The weak gravitational lensing of distant galaxies by a large-scale structure is expected to become a powerful probe of dark energy. By measuring the ellipticities of large number of background galaxies, the subtle gravitational distortion called 'cosmic shear' can be measured and used to constrain dark energy parameters. The observed galaxy ellipticities, however, are induced not by shear but by reduced shear, which also accounts for slight magnifications of the images. This distinction is negligible for present weak-lensing surveys, but it will become more important as we improve our ability to measure and understand small-angle cosmic shear modes. I calculate the discrepancy between shear and reduced shear in the context of power spectra and cross spectra, finding the difference could be as high as 10% on the smallest accessible angular scales. I estimate how this difference will bias dark energy parameters obtained from two weak-lensing methods: weak-lensing tomography and the shear ratio method known as offset-linear scaling. For weak-lensing tomography, ignoring the effects of reduced shear will cause future surveys considered by the Dark Energy Task Force to measure dark energy parameters that are biased by amounts comparable to their error bars. I advocate that reduced shear be properly accounted for in such surveys, and I provide a semi-analytic formula for doing so. Since reduced shear cross spectra do not follow an offset-linear scaling relation, the shear ratio method is similarly biased but with smaller significance.

  6. Gravitational Lensing Mass Mapping with Gaussian Processes

    Science.gov (United States)

    Schneider, Michael; Ng, Karen; Dawson, William; Marshall, Phil; Meyers, Joshua; Bard, Deborah

    2018-01-01

    We infer gravitational lensing shear and convergence fields from galaxy ellipticity catalogs under a Gaussian 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 orGaussian-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 present computational performance metrics with approximate algorithms that introduce sparsity in the Gaussian Process kernel.

  7. Galaxy formation from annihilation-generated supersonic turbulence in the baryon-symmetric big-bang cosmology and the gamma ray background spectrum

    Science.gov (United States)

    Stecker, F. W.; Puget, J. L.

    1972-01-01

    Following the big-bang baryon symmetric cosmology of Omnes, the redshift was calculated to be on the order of 500-600. It is show that, at these redshifts, annihilation pressure at the boundaries between regions of matter and antimatter drives large scale supersonic turbulence which can trigger galaxy formation. This picture is consistent with the gamma-ray background observations discussed previously. Gravitational binding of galaxies then occurs at a redshift of about 70, at which time vortical turbulent velocities of about 3 x 10 to the 7th power cm/s lead to angular momenta for galaxies comparable with measured values.

  8. First Weak-lensing Results from “See Change”: Quantifying Dark Matter in the Two z ≳ 1.5 High-redshift Galaxy Clusters SPT-CL J2040-4451 and IDCS J1426+3508

    Science.gov (United States)

    Jee, M. James; Ko, Jongwan; Perlmutter, Saul; Gonzalez, Anthony; Brodwin, Mark; Linder, Eric; Eisenhardt, Peter

    2017-10-01

    We present a weak-lensing study of SPT-CL J2040-4451 and IDCS J1426+3508 at z = 1.48 and 1.75, respectively. The two clusters were observed in our “See Change” program, a Hubble Space Telescope survey of 12 massive high-redshift clusters aimed at high-z supernova measurements and weak-lensing estimation of accurate cluster masses. We detect weak but significant galaxy shape distortions using infrared images from the Wide Field Camera 3 (WFC3), which has not yet been used for weak-lensing studies. Both clusters appear to possess relaxed morphology in projected mass distribution, and their mass centroids agree nicely with those defined by both the galaxy luminosity and X-ray emission. Using a Navarro-Frenk-White profile, for which we assume that the mass is tightly correlated with the concentration parameter, we determine the masses of SPT-CL J2040-4451 and IDCS J1426 + 3508 to be {M}200={8.6}-1.4+1.7× {10}14 {M}⊙ and {2.2}-0.7+1.1× {10}14 {M}⊙ , respectively. The weak-lensing mass of SPT-CL J2040-4451 shows that the cluster is clearly a rare object. Adopting the central value, the expected abundance of such a massive cluster at z≳ 1.48 is only ˜ 0.07 in the parent 2500 sq. deg. survey. However, it is yet premature to claim that the presence of this cluster creates a serious tension with the current ΛCDM paradigm unless that tension will remain in future studies after marginalizing over many sources of uncertainties such as the accuracy of the mass function and the mass-concentration relation at the high-mass end. The mass of IDCS J1426+3508 is in excellent agreement with our previous Advanced Camera for Surveys-based weak-lensing result, while the much higher source density from our WFC3 imaging data makes the current statistical uncertainty ˜ 40% smaller.

  9. Weak Weak Lensing : How Accurately Can Small Shears be Measured?

    NARCIS (Netherlands)

    Kuijken, K.

    2006-01-01

    Abstract: Now that weak lensing signals on the order of a percent are actively being searched for (cosmic shear, galaxy-galaxy lensing, large radii in clusters...) it is important to investigate how accurately weak shears can be determined. Many systematic effects are present, and need to be

  10. Imaging the Lenses in the Quintuple Gravitational Lens PMN J0134-0931

    Science.gov (United States)

    Wiklind, Tommy

    2017-08-01

    The gravitational lens PMN J0134-0931 is one of only two known non-cluster lenses producing six images of the background source. In this case the source is a quasar located at z=2.2 and the lens plane at z=0.76. It is likely that a small compact group of galaxies are located in the lens plane. The lens modeling for these six-image systems has, however, proven to be extraordinarily complicated and no satisfactory lens model has been produced for this system.PMN J0194-0931 is also unique in the sense that it is one of only two cases where molecular absorption lines are seen against two or more background images, the other one being PKS1830-211. The absorption lines make it possible to probe the kinematics of the lensing galaxies on sub-kpc scales and to determine kinematically derived total masses. Comparing with the mass derived from lens models, it provides a test of the assumed dark matter halo profile. In order to use the absorption lines to constrain the rotation curve it is necessary to know where the sigh lines cross the galaxies, the galaxy center and their inclination.The goal with this proposal is to image the galaxies at z=0.76 that lens the background quasar PMN J0134-0931. At optical and near-infrared wavelengths the highly magnified background quasar dominates the light. Attempts to subtract the quasar light has not produced useable results. We propose to observe PMN J0134-0931 at a wavelength short of the redshifted Lyman limit of the background quasar. This ensures that the quasar is essentially turned off. This can be accomplished by using the WFC3/F275W filter. The lensing galaxies will be observed in restframe 1500A.

  11. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    Science.gov (United States)

    Melchior, P.; Suchyta, E.; Huff, E.; Hirsch, M.; Kacprzak, T.; Rykoff, E.; Gruen, D.; Armstrong, R.; Bacon, D.; Bechtol, K.; Bernstein, G. M.; Bridle, S.; Clampitt, J.; Honscheid, K.; Jain, B.; Jouvel, S.; Krause, E.; Lin, H.; MacCrann, N.; Patton, K.; Plazas, A.; Rowe, B.; Vikram, V.; Wilcox, H.; Young, J.; Zuntz, J.; Abbott, T.; Abdalla, F. B.; Allam, S. S.; Banerji, M.; Bernstein, J. P.; Bernstein, R. A.; Bertin, E.; Buckley-Geer, E.; Burke, D. L.; Castander, F. J.; da Costa, L. N.; Cunha, C. E.; Depoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Evrard, A. E.; Neto, A. Fausti; Fernandez, E.; Finley, D. A.; Flaugher, B.; Frieman, J. A.; Gaztanaga, E.; Gerdes, D.; Gruendl, R. A.; Gutierrez, G. R.; Jarvis, M.; Karliner, I.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marriner, J.; Marshall, J. L.; Merritt, K. W.; Miller, C. J.; Miquel, R.; Mohr, J.; Neilsen, E.; Nichol, R. C.; Nord, B. D.; Reil, K.; Roe, N. A.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B. X.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, C.; Soares-Santos, M.; Swanson, M. E. C.; Sypniewski, A. J.; Tarle, G.; Thaler, J.; Thomas, D.; Tucker, D. L.; Walker, A.; Wechsler, R.; Weller, J.; Wester, W.

    2015-05-01

    We measure the weak lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey (DES). This pathfinder study is meant to (1) validate the Dark Energy Camera (DECam) imager for the task of measuring weak lensing shapes, and (2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, point spread function (PSF) modelling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well behaved, but the modelling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting Navarro-Frenk-White profiles to the clusters in this study, we determine weak lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak lensing mass, and richness. In addition, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1°(approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.

  12. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    Energy Technology Data Exchange (ETDEWEB)

    Melchior, P.; Suchyta, E.; Huff, E.; Hirsch, M.; Kacprzak, T.; Rykoff, E.; Gruen, D.; Armstrong, R.; Bacon, D.; Bechtol, K.; Bernstein, G. M.; Bridle, S.; Clampitt, J.; Honscheid, K.; Jain, B.; Jouvel, S.; Krause, E.; Lin, H.; MacCrann, N.; Patton, K.; Plazas, A.; Rowe, B.; Vikram, V.; Wilcox, H.; Young, J.; Zuntz, J.; Abbott, T.; Abdalla, F. B.; Allam, S. S.; Banerji, M.; Bernstein, J. P.; Bernstein, R. A.; Bertin, E.; Buckley-Geer, E.; Burke, D. L.; Castander, F. J.; da Costa, L. N.; Cunha, C. E.; Depoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Evrard, A. E.; Neto, A. F.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Frieman, J. A.; Gaztanaga, E.; Gerdes, D.; Gruendl, R. A.; Gutierrez, G. R.; Jarvis, M.; Karliner, I.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marriner, J.; Marshall, J. L.; Merritt, K. W.; Miller, C. J.; Miquel, R.; Mohr, J.; Neilsen, E.; Nichol, R. C.; Nord, B. D.; Reil, K.; Roe, N. A.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B. X.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, C.; Soares-Santos, M.; Swanson, M. E. C.; Sypniewski, A. J.; Tarle, G.; Thaler, J.; Thomas, D.; Tucker, D. L.; Walker, A.; Wechsler, R.; Weller, J.; Wester, W.

    2015-03-31

    We measure the weak-lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey. This pathfinder study is meant to 1) validate the DECam imager for the task of measuring weak-lensing shapes, and 2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, PSF modeling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well-behaved, but the modeling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting NFW profiles to the clusters in this study, we determine weak-lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak-lensing mass, and richness. In addition, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1 degree (approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.

  13. Gravitational Lensing of Supernova Neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Mena, Olga; /Fermilab /Rome U.; Mocioiu, Irina; /Penn State U.; Quigg, Chris; /Fermilab

    2006-10-01

    The black hole at the center of the galaxy is a powerful lens for supernova neutrinos. In the very special circumstance of a supernova near the extended line of sight from Earth to the galactic center, lensing could dramatically enhance the neutrino flux at Earth and stretch the neutrino pulse.

  14. The Optical Gravitational Lensing Experiment

    Science.gov (United States)

    Udalski, A.; Szymanski, M.; Kaluzny, J.; Kubiak, M.; Mateo, Mario

    1992-01-01

    The technical features are described of the Optical Gravitational Lensing Experiment, which aims to detect a statistically significant number of microlensing events toward the Galactic bulge. Clusters of galaxies observed during the 1992 season are listed and discussed and the reduction methods are described. Future plans are addressed.

  15. The WFIRST Galaxy Survey Exposure Time Calculator

    Science.gov (United States)

    Hirata, Christopher M.; Gehrels, Neil; Kneib, Jean-Paul; Kruk, Jeffrey; Rhodes, Jason; Wang, Yun; Zoubian, Julien

    2013-01-01

    This document describes the exposure time calculator for the Wide-Field Infrared Survey Telescope (WFIRST) high-latitude survey. The calculator works in both imaging and spectroscopic modes. In addition to the standard ETC functions (e.g. background and SN determination), the calculator integrates over the galaxy population and forecasts the density and redshift distribution of galaxy shapes usable for weak lensing (in imaging mode) and the detected emission lines (in spectroscopic mode). The source code is made available for public use.

  16. Lensing-induced morphology changes in CMB temperature maps in modified gravity theories

    Energy Technology Data Exchange (ETDEWEB)

    Munshi, D.; Coles, P. [Astronomy Centre, School of Mathematical and Physical Sciences, University of Sussex, Brighton BN1 9QH (United Kingdom); Hu, B. [Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, E08028 Barcelona (Spain); Matsubara, T. [Kobayashi-Maskawa Institute, Nagoya University, Chikusa, Nagoya 464-8602 (Japan); Heavens, A., E-mail: D.Munshi@sussex.ac.uk, E-mail: binhu@icc.ub.edu, E-mail: taka@kmi.nagoya-u.ac.jp, E-mail: P.Coles@sussex.ac.uk, E-mail: a.heavens@imperial.ac.uk [Imperial Centre for Inference and Cosmology, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom)

    2016-04-01

    Lensing of the Cosmic Microwave Background (CMB) changes the morphology of pattern of temperature fluctuations, so topological descriptors such as Minkowski Functionals can probe the gravity model responsible for the lensing. We show how the recently introduced two-to-two and three-to-one kurt-spectra (and their associated correlation functions), which depend on the power spectrum of the lensing potential, can be used to probe modified gravity theories such as f ( R ) theories of gravity and quintessence models. We also investigate models based on effective field theory, which include the constant-Ω model, and low-energy Hořava theories. Estimates of the cumulative signal-to-noise for detection of lensing-induced morphology changes, reaches O(10{sup 3}) for the future planned CMB polarization mission COrE{sup +}. Assuming foreground removal is possible to ℓ{sub max}=3000, we show that many modified gravity theories can be rejected with a high level of significance, making this technique comparable in power to galaxy weak lensing or redshift surveys. These topological estimators are also useful in distinguishing lensing from other scattering secondaries at the level of the four-point function or trispectrum. Examples include the kinetic Sunyaev-Zel'dovich (kSZ) effect which shares, with lensing, a lack of spectral distortion. We also discuss the complication of foreground contamination from unsubtracted point sources.

  17. 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.

  18. Dynamics of Galaxy Clusters and their Outskirts

    DEFF Research Database (Denmark)

    Falco, Martina

    Galaxy clusters have demonstrated to be powerful probes of cosmology, since their mass and abundance depend on the cosmological model that describes the Universe and on the gravitational formation process of cosmological structures. The main challenge in using clusters to constrain cosmology...... is that their masses cannot be measured directly, but need to be inferred indirectly through their observable properties. The most common methods extract the cluster mass from their strong X-ray emission or from the measured redshifts of the galaxy members. The gravitational lensing effect caused by clusters...... on the background galaxies is also an important trace of their total mass distribution.In the work presented within this thesis, we exploit the connection between the gravitational potential of galaxy clusters and the kinematical properties of their surroundings, in order to determine the total cluster mass...

  19. Cross-correlation of gravitational lensing from DES Science Verification data with SPT and Planck lensing

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, D.; Omori, Y.; Benoit-Lévy, A.; Cawthon, R.; Chang, C.; Larsen, P.; Amara, A.; Bacon, D.; Crawford, T. M.; Dodelson, S.; Fosalba, P.; Giannantonio, T.; Holder, G.; Jain, B.; Kacprzak, T.; Lahav, O.; MacCrann, N.; Nicola, A.; Refregier, A.; Sheldon, E.; Story, K. T.; Troxel, M. A.; Vieira, J. D.; Vikram, V.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Becker, M. R.; Benson, B. A.; Bernstein, G. M.; Bernstein, R. A.; Bleem, L. E.; Bonnett, C.; Bridle, S. L.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carlstrom, J. E.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Crocce, M.; Cunha, C. E.; D' Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Jarvis, M.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lima, M.; March, M.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Reichardt, C. L.; Roodman, A.; Rozo, E.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Simard, G.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Wechsler, R. H.; Weller, J.

    2016-03-10

    We measure the cross-correlation between weak lensing of galaxy images and of the cosmic microwave background (CMB). The effects of gravitational lensing on different sources will be correlated if the lensing is caused by the same mass fluctuations. We use galaxy shape measurements from 139 deg$^{2}$ of the Dark Energy Survey (DES) Science Verification data and overlapping CMB lensing from the South Pole Telescope (SPT) and Planck. The DES source galaxies have a median redshift of $z_{\\rm med} {\\sim} 0.7$, while the CMB lensing kernel is broad and peaks at $z{\\sim}2$. The resulting cross-correlation is maximally sensitive to mass fluctuations at $z{\\sim}0.44$. Assuming the Planck 2015 best-fit cosmology, the amplitude of the DES$\\times$SPT cross-power is found to be $A = 0.88 \\pm 0.30$ and that from DES$\\times$Planck to be $A = 0.86 \\pm 0.39$, where $A=1$ corresponds to the theoretical prediction. These are consistent with the expected signal and correspond to significances of $2.9 \\sigma$ and $2.2 \\sigma$ respectively. We demonstrate that our results are robust to a number of important systematic effects including the shear measurement method, estimator choice, photometric redshift uncertainty and CMB lensing systematics. Significant intrinsic alignment of galaxy shapes would increase the cross-correlation signal inferred from the data; we calculate a value of $A = 1.08 \\pm 0.36$ for DES$\\times$SPT when we correct the observations with a simple IA model. With three measurements of this cross-correlation now existing in the literature, there is not yet reliable evidence for any deviation from the expected LCDM level of cross-correlation, given the size of the statistical uncertainties and the significant impact of systematic errors, particularly IAs. We provide forecasts for the expected signal-to-noise of the combination of the five-year DES survey and SPT-3G.

  20. The Discovery and Properties of a Newly Discovered Compact Lensing Cluster CLIO at z=0.42: A unique JWST target

    Science.gov (United States)

    Conselice, Christopher; Griffiths, Alex; Alpaslan, Mehmet; Frye, Brenda; Zitrin, Adi; Diego, Jose; Yan, Haojing; Ma, Zhiyuan; Barone-Nugent, Robert; Bhatawdekar, Rachana; Driver, Simon; Robotham, Aaron; Windhorst, Rogier; Wyithe, Stuart

    2018-01-01

    We present the results of a new study of a unique compact lensing cluster we name CLIO at redshift 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 identied 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 imaging. Using deep FORS2 and Spitzer imaging in combination with MUSE optical spectroscopy we identify 89 cluster members and background sources out to z = 5.79. We describe the physical state of this cluster, finding a strong correlation between environment and galaxy spectral type. We furthermore measure the total mass of CLIO to be 4$\\times 10^{14}$ solar masses . We build and present an initial strong-lensing model for this cluster, and measure a relatively low intracluster light (ICL) fraction of ~7%. Due to its strong potential for lensing background galaxies and its low ICL, the CLIO cluster will be a target for our 110 hour JWST `Webb Medium-Deep Field' (WMDF) GTO program.

  1. Halo-lensing or Self-lensing? Locating the MACHO Lenses

    Science.gov (United States)

    Nelson, C. A.; Cook, K. H.; Popowski, P.; Drake, A. J.; Marshall, S. L.; Griest, K.; Vandehei, T.; Alcock, C.; Allsman, R. A.; Axelrod, T. S.; Freeman, K. C.; Peterson, B. A.; Alves, D. R.; Becker, A. C.; Stubbs, C. W.; Tomaney, A. B.; Bennett, D. P.; Geha, M.; Lehner, M. J.; Minniti, D.; Pratt, M. R.; Quinn, P. J.; Sutherland, W.; Welch, D.; MACHO Collaboration

    2000-12-01

    There are two principle geometrical arrangements which may explain Large Magellanic Cloud (LMC) microlensing: a) halo-lensing, in which the lensed object is part of the Milky Way galactic halo and b) self-lensing, in which the lensed object is part of the LMC. Self-lensing in turn may be broken into two categories: LMC-LMC self-lensing, in which both the source and the lens reside in the LMC and background self-lensing, in which the lens is a star in the LMC and the source star is drawn from some population behind the LMC. Models suggest the contribution of LMC-LMC self-lensing is small, so the nature of LMC microlensing may be estimated from the location of the microlensing source stars. If the source stars are in the LMC then microlensing is dominated by halo-lensing; conversely if the source stars are located behind the LMC then microlensing is dominated by self-lensing. Since background populations reside behind the LMC, we expect them to be both redder and fainter then the average population of the LMC. We attempt to determine if the MACHO source stars come from such a background population by comparing the HST color-magnitude diagram (CMD) of source stars to the CMD of the average population of the LMC and looking for the effects of extra reddening and extinction. The microlensing source stars are identified by deriving accurate centroids in the ground-based MACHO images using difference image analysis (DIA) and then transforming the DIA coordinates to the HST frame. Preliminary results suggest that halo-lensing accounts for ≳ 40% of the observed microlensing results. Support provided by NASA, DOE, NSF and NPSC.

  2. Constraining dark sector perturbations II: ISW and CMB lensing tomography

    Science.gov (United States)

    Soergel, B.; Giannantonio, T.; Weller, J.; Battye, R. A.

    2015-02-01

    Any Dark Energy (DE) or Modified Gravity (MG) model that deviates from a cosmological constant requires a consistent treatment of its perturbations, which can be described in terms of an effective entropy perturbation and an anisotropic stress. We have considered a recently proposed generic parameterisation of DE/MG perturbations and compared it to data from the Planck satellite and six galaxy catalogues, including temperature-galaxy (Tg), CMB lensing-galaxy (varphi g) and galaxy-galaxy (gg) correlations. Combining these observables of structure formation with tests of the background expansion allows us to investigate the properties of DE/MG both at the background and the perturbative level. Our constraints on DE/MG are mostly in agreement with the cosmological constant paradigm, while we also find that the constraint on the equation of state w (assumed to be constant) depends on the model assumed for the perturbation evolution. We obtain w=-0.92+0.20-0.16 (95% CL; CMB+gg+Tg) in the entropy perturbation scenario; in the anisotropic stress case the result is w=-0.86+0.17-0.16. Including the lensing correlations shifts the results towards higher values of w. If we include a prior on the expansion history from recent Baryon Acoustic Oscillations (BAO) measurements, we find that the constraints tighten closely around w=-1, making it impossible to measure any DE/MG perturbation evolution parameters. If, however, upcoming observations from surveys like DES, Euclid or LSST show indications for a deviation from a cosmological constant, our formalism will be a useful tool towards model selection in the dark sector.

  3. Joint measurement of lensing–galaxy correlations using SPT and DES SV data

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, E.; Clampitt, J.; Giannantonio, T.; Dodelson, S.; Jain, B.; Huterer, D.; Bleem, L.; Crawford, T.; Efstathiou, G.; Fosalba, P.; Kirk, D.; Kwan, J.; Sánchez, C.; Story, K.; Troxel, M. A.; Abbott, T. M. C.; Abdalla, F. B.; Armstrong, R.; Benoit-Lévy, A.; Benson, B.; Bernstein, G. M.; Bernstein, R. A.; Bertin, E.; Brooks, D.; Carlstrom, J.; Rosell, A. Carnero; Carrasco Kind, M.; Carretero, J.; Chown, R.; Crocce, M.; Cunha, C. E.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Fausti Neto, A.; Flaugher, B.; Frieman, J.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; de Haan, T.; Holder, G.; Honscheid, K.; Hou, Z.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lima, M.; March, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nord, B.; Omori, Y.; Plazas, A. A.; Reichardt, C.; Romer, A. K.; Rykoff, E. S.; Sanchez, E.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Stark, A.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.; Wechsler, R. H.

    2016-07-04

    We measure the correlation of galaxy lensing and cosmic microwave background lensing with a set of galaxies expected to trace the matter density field. The measurements are performed using pre-survey Dark Energy Survey (DES) Science Verification optical imaging data and millimetre-wave data from the 2500 sq. deg. South Pole Telescope Sunyaev–Zel'dovich (SPT-SZ) survey. The two lensing–galaxy correlations are jointly fit to extract constraints on cosmological parameters, constraints on the redshift distribution of the lens galaxies, and constraints on the absolute shear calibration of DES galaxy-lensing measurements. We show that an attractive feature of these fits is that they are fairly insensitive to the clustering bias of the galaxies used as matter tracers. The measurement presented in this work confirms that DES and SPT data are consistent with each other and with the currently favoured Λ cold dark matter cosmological model. It also demonstrates that joint lensing–galaxy correlation measurement considered here contains a wealth of information that can be extracted using current and future surveys.

  4. 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.

  5. Weighing 'El Gordo' with a precision scale: Hubble space telescope weak-lensing analysis of the merging galaxy cluster ACT-CL J0102–4915 at z = 0.87

    Energy Technology Data Exchange (ETDEWEB)

    Jee, M. James; Ng, Karen Y. [Department of Physics, University of California, Davis, One Shields Avenue, Davis, CA 95616 (United States); Hughes, John P.; Menanteau, Felipe [Department of Physics and Astronomy, Rutgers University, 136 Frelinghysen Rd., Piscataway, NJ 08854 (United States); Sifón, Cristóbal [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Mandelbaum, Rachel [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Barrientos, L. Felipe; Infante, Leopoldo [Departamento de Astronomía y Astrofísica, Facultad de Física, Ponticia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile)

    2014-04-10

    We present a Hubble Space Telescope weak-lensing study of the merging galaxy cluster 'El Gordo' (ACT-CL J0102–4915) at z = 0.87 discovered by the Atacama Cosmology Telescope (ACT) collaboration as the strongest Sunyaev-Zel'dovich decrement in its ∼1000 deg{sup 2} survey. Our weak-lensing analysis confirms that ACT-CL J0102–4915 is indeed an extreme system consisting of two massive (≳ 10{sup 15} M {sub ☉} each) subclusters with a projected separation of ∼0.7 h{sub 70}{sup −1} Mpc. This binary mass structure revealed by our lensing study is consistent with the cluster galaxy distribution and the dynamical study carried out with 89 spectroscopic members. We estimate the mass of ACT-CL J0102–4915 by simultaneously fitting two axisymmetric Navarro-Frenk-White (NFW) profiles allowing their centers to vary. We use only a single parameter for the NFW mass profile by enforcing the mass-concentration relation from numerical simulations. Our Markov-Chain-Monte-Carlo analysis shows that the masses of the northwestern (NW) and the southeastern (SE) components are M{sub 200c}=(1.38±0.22)×10{sup 15} h{sub 70}{sup −1} M{sub ⊙} and (0.78±0.20)×10{sup 15} h{sub 70}{sup −1} M{sub ⊙}, respectively, where the quoted errors include only 1σ statistical uncertainties determined by the finite number of source galaxies. These mass estimates are subject to additional uncertainties (20%-30%) due to the possible presence of triaxiality, correlated/uncorrelated large scale structure, and departure of the cluster profile from the NFW model. The lensing-based velocity dispersions are 1133{sub −61}{sup +58} km s{sup −1} and 1064{sub −66}{sup +62} km s{sup −1} for the NW and SE components, respectively, which are consistent with their spectroscopic measurements (1290 ± 134 km s{sup –1} and 1089 ± 200 km s{sup –1}, respectively). The centroids of both components are tightly constrained (∼4'') and close to the optical luminosity

  6. The massive galaxy cluster XMMU J1230.3+1339 at z ˜ 1: colour-magnitude relation, Butcher-Oemler effect, X-ray and weak lensing mass estimates

    Science.gov (United States)

    Lerchster, M.; Seitz, S.; Brimioulle, F.; Fassbender, R.; Rovilos, M.; Böhringer, H.; Pierini, D.; Kilbinger, M.; Finoguenov, A.; Quintana, H.; Bender, R.

    2011-03-01

    We present results from the multiwavelength study of XMMU J1230.3+1339 at z˜ 1. We analyse deep multiband wide-field images from the Large Binocular Telescope (LBT), multi-object spectroscopy observations from VLT, as well as space-based serendipitous observations, from the GALEX and Chandra X-ray observatories. We apply a Bayesian photometric redshift code to derive the redshifts using the far-UV (FUV), near-UV (NUV) and the deep U, B, V, r, i, z data. We make further use of spectroscopic data from FORS2 to calibrate our photometric redshifts, and investigate the photometric and spectral properties of the early-type galaxies. We achieve an accuracy of ▵z/(1 +z)= 0.07 (0.04) and the fraction of catastrophic outliers is η= 13 (0) per cent, when using all (secure) spectroscopic data, respectively. The i-z against z colour-magnitude relation of the photo-z members shows a tight red sequence with a zero-point of 0.935 mag, and slope equal to -0.027. We observe evidence for a truncation at the faint end of the red-cluster-sequence and the Butcher-Oemler effect, finding a fraction of blue galaxies fb≈ 0.5. Further, we conduct a weak lensing analysis of the deep 26 × 26 arcmin r-band LBC image. The observed shear is fitted with a Single-Isothermal-Sphere and a Navarro-Frenk-White model to obtain the velocity dispersion and the model parameters, respectively. Our best-fitting values are, for the velocity dispersion σSIS= 1308 ± 284 km s-1, concentration parameter c= 4.0+14-2 and scale radius rs= 345+50-57 kpc. From a 38 ks Chandra X-ray observation we obtain an independent estimate of the cluster mass. In addition, we create a signal-to-noise ratio (S/N) map for the detection of the matter mass distribution of the cluster using the mass-aperture technique. We find excellent agreement of the mass concentration identified with weak lensing and the X-ray surface brightness. Combining our mass estimates from the kinematic, X-ray and weak lensing analyses we obtain a

  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. Can AGN and galaxy clusters explain the surface brightness fluctuations of the cosmic X-ray background?

    Science.gov (United States)

    Kolodzig, Alexander; Gilfanov, Marat; Hütsi, Gert; Sunyaev, Rashid

    2017-04-01

    Fluctuations of the surface brightness of cosmic X-ray background (CXB) carry unique information about faint and low-luminosity source populations, which is inaccessible for conventional large-scale structure (LSS) studies based on resolved sources. We used XBOOTES (5ks deep Chandra X-ray Observatory ACIS-I maps of the ˜ 9 deg2 Bootes field of the NOAO Deep Wide-Field Survey) to conduct the most accurate measurement to date of the power spectrum of fluctuations of the unresolved CXB on the angular scales of 3 arcsec-17 arcmin. We find that at sub-arcmin angular scales, the power spectrum is consistent with the active galactic nucleus (AGN) shot noise, without much need for any significant contribution from their one-halo term. This is consistent with the theoretical expectation that low-luminosity AGN reside alone in their dark matter haloes. However, at larger angular scales, we detect a significant LSS signal above the AGN shot noise. Its power spectrum, obtained after subtracting the AGN shot noise, follows a power law with the slope of -0.8 ± 0.1 and its amplitude is much larger than what can be plausibly explained by the two-halo term of AGN. We demonstrate that the detected LSS signal is produced by unresolved clusters and groups of galaxies. For the flux limit of the XBOOTES survey, their flux-weighted mean redshift equals ˜ 0.3, and the mean temperature of their intracluster medium (ICM), ≈ 1.4 keV, corresponds to the mass of M500 ˜ 1013.5 M⊙. The power spectrum of CXB fluctuations carries information about the redshift distribution of these objects and the spatial structure of their ICM on the linear scales of up to ˜Mpc, I.e. of the order of the virial radius.

  9. 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

  10. Dependence of GAMA galaxy halo masses on the cosmic web environment from 100 deg2 of KiDS weak lensing data

    NARCIS (Netherlands)

    Brouwer, Margot M.; Cacciato, Marcello; Dvornik, Andrej; Eardley, Lizzie; Heymans, Catherine; Hoekstra, Henk; Kuijken, Konrad; McNaught-Roberts, Tamsyn; Sifón, Cristóbal; Viola, Massimo; Alpaslan, Mehmet; Bilicki, Maciej; Bland-Hawthorn, Joss; Brough, Sarah; Choi, Ami; Driver, Simon P.; Erben, Thomas; Grado, Aniello; Hildebrandt, Hendrik; Holwerda, Benne W.; Hopkins, Andrew M.; de Jong, Jelte T. A.; Liske, Jochen; Mc Farland, John; Nakajima, Reiko; Napolitano, Nicola R.; Norberg, Peder; Peacock, John A.; Radovich, Mario; Robotham, Aaron S. G.; Schneider, Peter; Sikkema, Gert; van Uitert, Edo; Verdoes Kleijn, Gijs; Valentijn, Edwin A.

    2016-01-01

    Galaxies and their dark matter haloes are part of a complex network of mass structures, collectively called the cosmic web. Using the tidal tensor prescription these structures can be classified into four cosmic environments: voids, sheets, filaments and knots. As the cosmic web may influence the

  11. DARK MATTER SEARCHES IN THE GAMMA-RAY EXTRAGALACTIC BACKGROUND VIA CROSS-CORRELATIONS WITH GALAXY CATALOGS

    Energy Technology Data Exchange (ETDEWEB)

    Cuoco, Alessandro; Regis, Marco; Fornengo, Nicolao [Dipartimento di Fisica, Università di Torino, via P. Giuria 1, I-10125 Torino (Italy); Xia, Jun-Qing [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Branchini, Enzo [Dipartimento di Matematica e Fisica, Università degli Studi “Roma Tre,” via della Vasca Navale 84, I-00146 Roma (Italy); Viel, Matteo, E-mail: cuoco@to.infn.it, E-mail: regis@to.infn.it, E-mail: fornengo@to.infn.it, E-mail: xiajq@bnu.edu.cn, E-mail: branchin@fis.uniroma3.it, E-mail: viel@oats.inaf.it [INAF Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, I-34141, Trieste (Italy)

    2015-12-15

    We compare the measured angular cross-correlation between the Fermi-Large Area Telescope γ-ray sky and catalogs of extragalactic objects with the expected signal induced by weakly interacting massive particle (WIMP) dark matter (DM). We include a detailed description of the contribution of astrophysical γ-ray emitters such as blazars, misaligned active galactic nucleus (AGN), and star-forming galaxies, and perform a global fit to the measured cross-correlation. Five catalogs are considered: Sloan Digital Sky Survey (SDSS)-DR6 quasars, Two Micron All Sky Survey galaxies, NRAO VLA Sky Survey radio galaxies, SDSS-DR8 Luminous Red Galaxies, and the SDSS-DR8 main galaxy sample. To model the cross-correlation signal, we use the halo occupation distribution formalism to estimate the number of galaxies of a given catalog in DM halos and their spatial correlation properties. We discuss uncertainties in the predicted cross-correlation signal arising from the DM clustering and WIMP microscopic properties, which set the DM γ-ray emission. The use of different catalogs probing objects at different redshifts significantly reduces, though not completely, the degeneracy among the different γ-ray components. We find that the presence of a significant WIMP DM signal is allowed by the data but not significantly preferred by the fit, although this is mainly due to a degeneracy with the misaligned AGN component. With modest substructure boost, the sensitivity of this method excludes thermal annihilation cross sections at 95% level for WIMP masses up to few tens of GeV. Constraining the low-redshift properties of astrophysical populations with future data will further improve the sensitivity to DM.

  12. Studying the ICM in clusters of galaxies via surface brightness fluctuations of the cosmic X-ray background

    Science.gov (United States)

    Kolodzig, Alexander; Gilfanov, Marat; Hütsi, Gert; Sunyaev, Rashid

    2018-02-01

    We study surface brightness fluctuations of the cosmic X-ray background (CXB) using Chandra data of XBOOTES. After masking out resolved sources we compute the power spectrum of fluctuations of the unresolved CXB for angular scales from {≈ } 2 arcsec to ≈3°. The non-trivial large-scale structure (LSS) signal dominates over the shot noise of unresolved point sources on angular scales above {˜ } 1 arcmin and is produced mainly by the intracluster medium (ICM) of unresolved clusters and groups of galaxies, as shown in our previous publication. The shot-noise-subtracted power spectrum of CXB fluctuations has a power-law shape with the slope of Γ = 0.96 ± 0.06. Their energy spectrum is well described by the redshifted emission spectrum of optically thin plasma with the best-fitting temperature of T ≈ 1.3 keV and the best-fitting redshift of z ≈ 0.40. These numbers are in good agreement with theoretical expectations based on the X-ray luminosity function and scaling relations of clusters. From these values we estimate the typical mass and luminosity of the objects responsible for CXB fluctuations, M500 ∼ 1013.6 M⊙ h-1 and L0.5-2.0 keV ∼ 1042.5 erg s-1. On the other hand, the flux-weighted mean temperature and redshift of resolved clusters are T ≈ 2.4 keV and z ≈ 0.23 confirming that fluctuations of unresolved CXB are caused by cooler (i.e. less massive) and more distant clusters, as expected. We show that the power spectrum shape is sensitive to the ICM structure all the way to the outskirts, out to ∼few × R500. We also searched for possible contribution of the warm-hot intergalactic medium (WHIM) to the observed CXB fluctuations. Our results underline the significant diagnostic potential of the CXB fluctuation analysis in studying the ICM structure in clusters.

  13. 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.

  14. What is Gravitational Lensing? (LBNL Summer Lecture Series)

    Energy Technology Data Exchange (ETDEWEB)

    Leauthaud, Alexie; Nakajima, Reiko [Berkeley Center for Cosmological Physics

    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.

  15. Using Weak-Lensing Dilution to Measure Light Properties of A1689

    Science.gov (United States)

    Medezinski, Elinor; Broadhurst, Tom; Umetsu, Keiichi; Coe, Dan

    Weak-lensing induced by clusters of galaxies can probe the total mass distribution out to the virial radius of the cluster, regardless of the nature of the mass or its dynamical state. To make a robust analysis, the cluster and background galaxy populations need to be separated. The E/S0 sequence of a cluster defines a boundary redward of which a reliable weak-lensing signal can be obtained from background galaxies, uncontaminated by the cluster. Below this limit, the signal is diluted by the proportion of unlensed cluster members. Employing deep Subaru and HST/ACS images of the massive cluster A1689, we use this dilution effect to carefully separate between the cluster members and the background, and thus derive the cluster light profile and luminosity functions to large radius. The light profile of A1689 is found to decline steadily to the limit of the data, r cluster luminosity function with a flat faint-end slope of α = -1.05 ± 0.07, nearly independent of radius and with no faint upturn to Mi‧ subtraction of far-field background counts is required.

  16. A Comparison Of X-ray, Radio, And Lensing Results With GBT+MUSTANG Observations Of The Sunyaev-Zel'dovich Effect In Galaxy Clusters

    Science.gov (United States)

    Mroczkowski, Tony; Devlin, M.; Dicker, S.; Korngut, P.; Mason, B.; Reese, E.; Romero, C.; Sarazin, C.; Sun, M.; Young, A.; Lensing, Cluster; survey with Hubble, Supernova

    2012-05-01

    We present recent high angular resolution (9") Sunyaev-Zel'dovich effect (SZE) observations with MUSTANG, a 90-GHz bolometric receiver on the 100-meter Green Bank Telescope (GBT). MUSTANG is now imaging a sample of clusters with complementary Chandra X-ray observations, HST optical observations that probe the mass distribution through strong and weak lensing, radio observations that probe the non-thermal component of the intra-cluster gas, and lower resolution SZE observations that can recover larger scales (>1'). The MUSTANG observations, which will be used to assess the impact of substructure on SZE scaling relations, are some of the highest resolution SZE images to date, and are revealing complex pressure substructures in intermediate redshift clusters. Combined, these observations reveal complicated cluster dynamics, which must be understood in order to use clusters as cosmological probes.

  17. Gravitational lensing effect and polarization of the cosmic microwave background in the PLANCK Experiment and post-planckian projects; Effet de lentilles gravitationnelles et polarisation du fond diffus cosmologique dans le cadre de l'experience PLANCK et de projets post-planckiens

    Energy Technology Data Exchange (ETDEWEB)

    Perotto, Laurence [Universite Paris 7 - Denis Diderot, UFR de Physique, 75205 Paris Cedex 13 (France)

    2006-01-15

    This thesis is motivated by the upcoming high-resolution, high-sensitivity microwave background experiments, which should be sensitive to the CMB polarization and lensing. The first chapter provides a review of the CMB polarization with emphasis on future related experiments. The PLANCK experiment is described in a second chapter, where I develop a fast simulation code of PLANCK time-ordered data optimized to ease elaboration and test of data analysis methods. The two last chapters deal with gravitational lensing of the cosmic background radiation. First, I evaluate the capability of the upcoming experiments mentioned above to measure the power spectrum of Large Scale Structure by means of the extraction of weak lensing. Then I derive their sensitivity to the total neutrino mass, using the suppression of power due to free-streaming of massive neutrinos. Finally, I develop a method to estimate the foreground effects in the gravitational lensing extraction process. This method uses the best linear estimator available in the literature and is validated by numerical simulations that include non-Gaussian CMB lensed maps and extra-galactic radio sources maps. I find that sources emission reduces the sensitivity of future experiments to the weak lensing and leads to an overestimate of the convergence power spectrum. (author)

  18. GRAVITATIONAL LENSES AND UNCONVENTIONAL GRAVITY THEORIES

    NARCIS (Netherlands)

    BEKENSTEIN, JD; SANDERS, RH

    1994-01-01

    We study gravitational lensing by clusters of galaxies in the context of the generic class of unconventional gravity theories which describe gravity in terms of a metric and one or more scalar fields (called here scalar-tensor theories). We conclude that, if the scalar fields have positive energy,

  19. 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

  20. 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 ...

  1. The diffuse source at the center of LMC SNR 0509–67.5 is a background galaxy at z = 0.031

    Energy Technology Data Exchange (ETDEWEB)

    Pagnotta, Ashley [Department of Astrophysics, American Museum of Natural History, New York, NY 10024 (United States); Walker, Emma S. [Department of Physics, Yale University, New Haven, CT 06520 (United States); Schaefer, Bradley E., E-mail: pagnotta@amnh.org [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States)

    2014-06-20

    Type Ia supernovae (SNe Ia) are well-known for their use in the measurement of cosmological distances, but our continuing lack of concrete knowledge about their progenitor stars is both a matter of debate and a source of systematic error. In our attempts to answer this question, we presented unambiguous evidence that LMC SNR 0509–67.5, the remnant of an SN Ia that exploded in the Large Magellanic Cloud 400 ± 50 yr ago, did not have any point sources (stars) near the site of the original supernova explosion, from which we concluded that this particular supernova must have had a progenitor system consisting of two white dwarfs. There is, however, evidence of nebulosity near the center of the remnant, which could have been left over detritus from the less massive WD, or could have been a background galaxy unrelated to the supernova explosion. We obtained long-slit spectra of the central nebulous region using GMOS on Gemini South to determine which of these two possibilities is correct. The spectra show Hα emission at a redshift of z = 0.031, which implies that the nebulosity in the center of LMC SNR 0509–67.5 is a background galaxy, unrelated to the supernova.

  2. The diffuse source at the center of LMC SNR 0509–67.5 is a background galaxy at z = 0.031

    International Nuclear Information System (INIS)

    Pagnotta, Ashley; Walker, Emma S.; Schaefer, Bradley E.

    2014-01-01

    Type Ia supernovae (SNe Ia) are well-known for their use in the measurement of cosmological distances, but our continuing lack of concrete knowledge about their progenitor stars is both a matter of debate and a source of systematic error. In our attempts to answer this question, we presented unambiguous evidence that LMC SNR 0509–67.5, the remnant of an SN Ia that exploded in the Large Magellanic Cloud 400 ± 50 yr ago, did not have any point sources (stars) near the site of the original supernova explosion, from which we concluded that this particular supernova must have had a progenitor system consisting of two white dwarfs. There is, however, evidence of nebulosity near the center of the remnant, which could have been left over detritus from the less massive WD, or could have been a background galaxy unrelated to the supernova explosion. We obtained long-slit spectra of the central nebulous region using GMOS on Gemini South to determine which of these two possibilities is correct. The spectra show Hα emission at a redshift of z = 0.031, which implies that the nebulosity in the center of LMC SNR 0509–67.5 is a background galaxy, unrelated to the supernova.

  3. 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.

  4. X-Rays from NGC 3256: High-Energy Emission in Starburst Galaxies and Their Contribution to the Cosmic X-Ray Background

    International Nuclear Information System (INIS)

    Moran, Edward C.; Lehnert, Matthew D.; Helfand, David J.

    1999-01-01

    The infrared-luminous galaxy NGC 3256 is a classic example of a merger-induced nuclear starburst system. We find here that it is the most X-ray-luminous star-forming galaxy yet detected (L 0.5-10keV =1.6x10 42 ergs s-1). Long-slit optical spectroscopy and a deep, high-resolution ROSAT X-ray image show that the starburst is driving a ''superwind'' which accounts for ∼20% of the observed soft X-ray emission. Analysis of X-ray spectral data from ASCA indicates this gas has a characteristic temperature of kT≅0.3 keV. Our model for the broadband X-ray emission of NGC 3256 contains two additional components: a warm thermal plasma (kT≅0.8 keV) associated with the central starburst, and a hard power-law component with an energy index of α X ≅0.7. We discuss the energy budget for the two thermal plasmas and find that the input of mechanical energy from the starburst is more than sufficient to sustain the observed level of emission. We also examine possible origins for the power-law component, concluding that neither a buried AGN nor the expected population of high-mass X-ray binaries can account for this emission. Inverse Compton scattering, involving the galaxy's copious flux of infrared photons and the relativistic electrons produced by supernovae, is likely to make a substantial contribution to the hard X-ray flux. Such a model is consistent with the observed radio and IR fluxes and the radio and X-ray spectral indices. We explore the role of X-ray-luminous starbursts in the production of the cosmic X-ray background radiation. The number counts and spectral index distribution of the faint radio source population, thought to be dominated by star-forming galaxies, suggest that a significant fraction of the hard X-ray background could arise from starbursts at moderate redshift. (c) (c) 1999. The American Astronomical Society

  5. On Using a Space Telescope to Detect Weak-lensing Shear

    Science.gov (United States)

    Tung, Nathan; Wright, Edward

    2017-11-01

    Ignoring redshift dependence, the statistical performance of a weak-lensing survey is set by two numbers: the effective shape noise of the sources, which includes the intrinsic ellipticity dispersion and the measurement noise, and the density of sources that are useful for weak-lensing measurements. In this paper, we provide some general guidance for weak-lensing shear measurements from a “generic” space telescope by looking for the optimum wavelength bands to maximize the galaxy flux signal-to-noise ratio (S/N) and minimize ellipticity measurement error. We also calculate an effective galaxy number per square degree across different wavelength bands, taking into account the density of sources that are useful for weak-lensing measurements and the effective shape noise of sources. Galaxy data collected from the ultra-deep UltraVISTA Ks-selected and R-selected photometric catalogs (Muzzin et al. 2013) are fitted to radially symmetric Sérsic galaxy light profiles. The Sérsic galaxy profiles are then stretched to impose an artificial weak-lensing shear, and then convolved with a pure Airy Disk PSF to simulate imaging of weak gravitationally lensed galaxies from a hypothetical diffraction-limited space telescope. For our model calculations and sets of galaxies, our results show that the peak in the average galaxy flux S/N, the minimum average ellipticity measurement error, and the highest effective galaxy number counts all lie around the K-band near 2.2 μm.

  6. GOLDEN GRAVITATIONAL LENSING SYSTEMS FROM THE SLOAN LENS ACS SURVEY. I. SDSS J1538+5817: ONE LENS FOR TWO SOURCES ,

    International Nuclear Information System (INIS)

    Grillo, C.; Seitz, S.; Bender, R.; Eichner, T.; Bauer, A.; Lombardi, M.; Gobat, R.

    2010-01-01

    We present a gravitational lensing and photometric study of the exceptional strong lensing system SDSS J1538+5817, identified by the Sloan Lens Advanced Camera for Survey. The lens is a luminous elliptical galaxy at redshift z l = 0.143. Using Hubble Space Telescope public images obtained with two different filters, the presence of two background sources lensed, respectively, into an Einstein ring and a double system is ascertained. Our new spectroscopic observations, performed at the Nordic Optical Telescope, reveal unequivocally that the two sources are located at the same redshift z s = 0.531. We investigate the total (luminous and dark) mass distribution of the lens between 1 and 4 kpc from the galaxy center by means of parametric and non-parametric lensing codes that describe the multiple images as point-like objects. Bootstrapping and Bayesian analyses are performed to determine the uncertainties on the quantities relevant to the lens mass characterization. Several disparate lensing models provide results that are consistent, given the errors, with those obtained from the best-fit model of the lens mass distribution in terms of a singular power-law ellipsoid model. In particular, the lensing models agree on: (1) reproducing accurately the observed positions of the images; (2) predicting a nearly axisymmetric total mass distribution, centered and oriented as the light distribution; (3) measuring a value of 8.11 +0.27 -0.59 x 10 10 M sun for the total mass projected within the Einstein radius of 2.5 kpc; and (4) estimating a total mass density profile slightly steeper than an isothermal one (ρ(r)∝r -2.33 +0.43 -0.20 ). A fit of the Sloan Digital Sky Survey multicolor photometry with composite stellar population models provides a value of 20 +1 -4 x 10 10 M sun for the total mass of the galaxy in the form of stars and of 0.9 +0.1 -0.2 for the fraction of projected luminous over total mass enclosed inside the Einstein radius. By combining lensing (total) and

  7. 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.

  8. Model of a black hole gas submitted to background gravitational field for active galaxy nuclei with application to calculating the continuous emission spectra of massless particles (Photons: neutrinos and gravitons)

    International Nuclear Information System (INIS)

    Pinto Neto, A.

    1987-01-01

    A new theoretical model for active galaxy nuclei which describes the continuous spectrum of rest massless particles (photons, neutrinos and gravitons) in the frequency range from radiofrequency to gamma ray frequency, is presented. The model consists in a black hole gas interacting with a background gravitacional field. The previously models proposed for active galaxy nuclei are exposured. Whole theoretical fundaments based on Einstein general relativity theory for defining and studying singularity properties (black holes) are also presented. (M.C.K.) [pt

  9. The unusual lensing BCG in Abell 1201: A steep IMF gradient, or an ultra-massive central black hole?

    Science.gov (United States)

    Smith, Russell

    2016-10-01

    Abell 1201 is a cluster of galaxies at z=0.17, with a brightest cluster galaxy (BCG) which acts as a gravitational lens to a background surce at z=0.45. The lensing configuration is unusual, with a single bright arc formed at small radius ( 5kpc), where the stars are expected to contribute substantially to the total lensing mass. Using VLT/MUSE data, we have recently discovered a faint counter-image to the main arc, located just 0.6 from the lens centre. This image is not predicted at all in lensing models which incorporate the mass contributions from stars (following the observed light profile) and dark matter. Modelling shows that the formation of the counter-image requires additional mass at small radius. Possible solutions include (a) imposing a gradient of the stellar-mass-to-light ratio, reflecting a heavier initial mass function (IMF) in the galaxy centre, or (b) adding a central black hole with mass above ten billion solar masses, comparable to the largest dynamical measurements. The first scenario would be relevant to ongoing controversies concering possible non-standard IMFs in massive elliptical galaxies. The second explanation would be the first lensing-based detection of a central black hole, with implications for the still sparsely-populated upper end of the black hole scaling relations.The two alternative models yield different predictions for the morphology of the counter-image. Our proposed WFC3/UVIS observations will establish whether the image is (a) a radial arc, supporting the IMF gradient interpretation, or (b) a compact counter-image, confirming the ultra-massive black hole scenario. HST resolution is essential for this measurement.

  10. Pulsar lensing geometry

    Science.gov (United States)

    Liu, Siqi; Pen, Ue-Li; Macquart, J.-P.; Brisken, Walter; Deller, Adam

    2016-05-01

    We test the inclined sheet pulsar scintillation model (Pen & Levin) against archival very long baseline interferometry (VLBI) data on PSR 0834+06 and show that its scintillation properties can be precisely reproduced by a model in which refraction occurs on two distinct lens planes. These data strongly favour a model in which grazing-incidence refraction instead of diffraction off turbulent structures is the primary source of pulsar scattering. This model can reproduce the parameters of the observed diffractive scintillation with an accuracy at the percent level. Comparison with new VLBI proper motion results in a direct measure of the ionized interstellar medium (ISM) screen transverse velocity. The results are consistent with ISM velocities local to the PSR 0834+06 sight-line (through the Galaxy). The simple 1-D structure of the lenses opens up the possibility of using interstellar lenses as precision probes for pulsar lens mapping, precision transverse motions in the ISM, and new opportunities for removing scattering to improve pulsar timing. We describe the parameters and observables of this double screen system. While relative screen distances can in principle be accurately determined, a global conformal distance degeneracy exists that allows a rescaling of the absolute distance scale. For PSR B0834+06, we present VLBI astrometry results that provide (for the first time) a direct measurement of the distance of the pulsar. For most of the recycled millisecond pulsars that are the targets of precision timing observations, the targets where independent distance measurements are not available. The degeneracy presented in the lens modelling could be broken if the pulsar resides in a binary system.

  11. The BOSS Emission-line Lens Survey. V. Morphology and Substructure of Lensed Lyα Emitters at Redshift Z ≈ 2.5 in the BELLS GALLERY

    Science.gov (United States)

    Cornachione, Matthew A.; Bolton, Adam S.; Shu, Yiping; Zheng, Zheng; Montero-Dorta, Antonio D.; Brownstein, Joel R.; Oguri, Masamune; Kochanek, Christopher S.; Mao, Shude; Pèrez-Fournon, Ismael; Marques-Chaves, Rui; Mènard, Brice

    2018-02-01

    We present a morphological study of the 17 lensed Lyα emitter (LAE) galaxies of the Baryon Oscillation Spectroscopic Survey Emission-Line Lens Survey (BELLS) for the GALaxy-Lyα EmitteR sYstems (BELLS GALLERY) sample. This analysis combines the magnification effect of strong galaxy–galaxy lensing with the high resolution of the Hubble Space Telescope to achieve a physical resolution of ∼80 pc for this 2 matter substructure in the foreground lensing galaxies.

  12. LENS MODELS OF HERSCHEL-SELECTED GALAXIES FROM HIGH-RESOLUTION NEAR-IR OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Calanog, J. A.; Cooray, A.; Ma, B.; Casey, C. M. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Fu, Hai [Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242 (United States); Wardlow, J. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Amber, S. [Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA (United Kingdom); Baker, A. J. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Baes, M. [1 Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281, B-9000 Gent (Belgium); Bock, J. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Bourne, N.; Dye, S. [School of Physics and Astronomy, University of Nottingham, NG7 2RD (United Kingdom); Bussmann, R. S. [Department of Astronomy, Space Science Building, Cornell University, Ithaca, NY 14853-6801 (United States); Chapman, S. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Conley, A. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Dannerbauer, H. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); De Zotti, G. [INAF-Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Dunne, L.; Eales, S. [School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); and others

    2014-12-20

    We present Keck-Adaptive Optics and Hubble Space Telescope high resolution near-infrared (IR) imaging for 500 μm bright candidate lensing systems identified by the Herschel Multi-tiered Extragalactic Survey and Herschel Astrophysical Terahertz Large Area Survey. Out of 87 candidates with near-IR imaging, 15 (∼17%) display clear near-IR lensing morphologies. We present near-IR lens models to reconstruct and recover basic rest-frame optical morphological properties of the background galaxies from 12 new systems. Sources with the largest near-IR magnification factors also tend to be the most compact, consistent with the size bias predicted from simulations and previous lensing models for submillimeter galaxies (SMGs). For four new sources that also have high-resolution submillimeter maps, we test for differential lensing between the stellar and dust components and find that the 880 μm magnification factor (μ{sub 880}) is ∼1.5 times higher than the near-IR magnification factor (μ{sub NIR}), on average. We also find that the stellar emission is ∼2 times more extended in size than dust. The rest-frame optical properties of our sample of Herschel-selected lensed SMGs are consistent with those of unlensed SMGs, which suggests that the two populations are similar.

  13. Measuring weak lensing correlations of Type Ia supernovae

    Science.gov (United States)

    Scovacricchi, D.; Nichol, R. C.; Macaulay, E.; Bacon, D.

    2017-03-01

    We study the feasibility of detecting weak lensing spatial correlations between supernova (SN) Type Ia magnitudes with present (Dark Energy Survey, DES) and future (Large Synoptic Survey Telescope, LSST) surveys. We investigate the angular auto-correlation function of SN magnitudes (once the background cosmology has been subtracted) and cross-correlation with galaxy catalogues. We examine both analytical and numerical predictions, the latter using simulated galaxy catalogues from the MICE Grand Challenge Simulation. We predict that we will be unable to detect the SN auto-correlation in DES, while it should be detectable with the LSST SN deep fields (15 000 SNe on 70 deg2) at ≃6σ level of confidence (assuming 0.15 mag of intrinsic dispersion). The SN-galaxy cross-correlation function will deliver much higher signal to noise, being detectable in both surveys with an integrated signal to noise of ∼100 (up to 30 arcmin separations). We predict joint constraints on the matter density parameter (Ωm) and the clustering amplitude (σ8) by fitting the auto-correlation function of our mock LSST deep fields. When assuming a Gaussian prior for Ωm, we can achieve a 25 per cent measurement of σ8 from just these LSST supernovae (assuming 0.15 mag of intrinsic dispersion). These constraints will improve significantly if the intrinsic dispersion of SNe Ia can be reduced.

  14. Galaxy Formation

    CERN Document Server

    Longair, Malcolm S

    2008-01-01

    This second edition of Galaxy Formation is an up-to-date text on astrophysical cosmology, expounding the structure of the classical cosmological models from a contemporary viewpoint. This forms the background to a detailed study of the origin of structure and galaxies in the Universe. The derivations of many of the most important results are derived by simple physical arguments which illuminate the results of more advanced treatments. A very wide range of observational data is brought to bear upon these problems, including the most recent results from WMAP, the Hubble Space Telescope, galaxy surveys like the Sloan Digital Sky Survey and the 2dF Galaxy Redshift Survey, studies of Type 1a supernovae, and many other observations.

  15. IDCS J1426.5+3508: COSMOLOGICAL IMPLICATIONS OF A MASSIVE, STRONG LENSING CLUSTER AT z = 1.75

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Anthony H.; Fedeli, Cosimo; Mancone, Conor [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States); Stanford, S. Adam; Zeimann, Greg [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Brodwin, Mark [Department of Physics, University of Missouri, 5110 Rockhill Road, Kansas City, MO 64110 (United States); Dey, Arjun [NOAO, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Eisenhardt, Peter R. M.; Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2012-07-10

    The galaxy cluster IDCS J1426.5+3508 at z = 1.75 is the most massive galaxy cluster yet discovered at z > 1.4 and the first cluster at this epoch for which the Sunyaev-Zel'Dovich effect has been observed. In this paper, we report on the discovery with Hubble Space Telescope imaging of a giant arc associated with this cluster. The curvature of the arc suggests that the lensing mass is nearly coincident with the brightest cluster galaxy, and the color is consistent with the arc being a star-forming galaxy. We compare the constraint on M{sub 200} based upon strong lensing with Sunyaev-Zel'Dovich results, finding that the two are consistent if the redshift of the arc is z {approx}> 3. Finally, we explore the cosmological implications of this system, considering the likelihood of the existence of a strongly lensing galaxy cluster at this epoch in a {Lambda}CDM universe. While the existence of the cluster itself can potentially be accommodated if one considers the entire volume covered at this redshift by all current high-redshift cluster surveys, the existence of this strongly lensed galaxy greatly exacerbates the long-standing giant arc problem. For standard {Lambda}CDM structure formation and observed background field galaxy counts this lens system should not exist. Specifically, there should be no giant arcs in the entire sky as bright in F814W as the observed arc for clusters at z {>=} 1.75, and only {approx}0.3 as bright in F160W as the observed arc. If we relax the redshift constraint to consider all clusters at z {>=} 1.5, the expected number of giant arcs rises to {approx}15 in F160W, but the number of giant arcs of this brightness in F814W remains zero. These arc statistic results are independent of the mass of IDCS J1426.5+3508. We consider possible explanations for this discrepancy.

  16. 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...

  17. Extragalactic background light from hierarchical galaxy formation. Gamma-ray attenuation up to the epoch of cosmic reionization and the first stars

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Yoshiyuki [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; Inoue, Susumu [Max Planck Inst. for Nuclear Physics, Heidelberg (Germany); Univ. of Tokyo (Japan). Inst. for Cosmic Ray Research; Kobayashi, Masakazu A. R. [Ehime Univ., Matsuyama (Japan). Research Center for Space and Cosmic Evolution; Makiya, Ryu [Kyoto Univ. (Japan). Dept. of Astronomy; Niino, Yuu [National Astronomical Observatory of Japan, Mitaka (Tokyo). Optical and Infrared Astronomy Division; Totani, Tomonori [Kyoto Univ. (Japan). Dept. of Astronomy

    2013-04-26

    Here, we present a new model of the extragalactic background light (EBL) and corresponding γγ opacity for intergalactic gamma-ray absorption from z = 0 up to z = 10, based on a semi-analytical model of hierarchical galaxy formation that reproduces key observed properties of galaxies at various redshifts. Including the potential contribution from Population III stars and following the cosmic reionization history in a simplified way, the model is also broadly consistent with available data concerning reionization, particularly the Thomson scattering optical depth constraints from Wilkinson Microwave Anisotropy Probe (WMAP). In comparison with previous EBL studies up to z ~ 3-5, our predicted γγ opacity is in general agreement for observed gamma-ray energy below 400/(1 + z) GeV, whereas it is a factor of ~2 lower above this energy because of a correspondingly lower cosmic star formation rate, even though the observed ultraviolet (UV) luminosity is well reproduced by virtue of our improved treatment of dust obscuration and direct estimation of star formation rate. Moreover, the horizon energy at which the gamma-ray opacity is unity does not evolve strongly beyond z ~ 4 and approaches ~20 GeV. The contribution of Population III stars is a minor fraction of the EBL at z = 0, and is also difficult to distinguish through gamma-ray absorption in high-z objects, even at the highest levels allowed by the WMAP constraints. Nevertheless, the attenuation due to Population II stars should be observable in high-z gamma-ray sources by telescopes such as Fermi or the Cherenkov Telescope Array and provide a valuable probe of the evolving EBL in the rest-frame UV. Our detailed results of our model are publicly available in numerical form at http://www.slac.stanford.edu/~yinoue/Download.html.

  18. New Theoretical Estimates of the Contribution of Unresolved Star-Forming Galaxies to the Extragalactic Gamma-Ray Background (EGB) as Measured by EGRET and the Fermi-LAT

    Science.gov (United States)

    Venters, Tonia M.

    2011-01-01

    We present new theoretical estimates of the contribution of unresolved star-forming galaxies to the extragalactic gamma-ray background (EGB) as measured by EGRET and the Fermi-LAT. We employ several methods for determining the star-forming galaxy contribution the the EGB, including a method positing a correlation between the gamma-ray luminosity of a galaxy and its rate of star formation as calculated from the total infrared luminosity, and a method that makes use of a model of the evolution of the galaxy gas mass with cosmic time. We find that depending on the model, unresolved star-forming galaxies could contribute significantly to the EGB as measured by the Fermi-LAT at energies between approx. 300 MeV and approx. few GeV. However, the overall spectrum of unresolved star-forming galaxies can explain neither the EGRET EGB spectrum at energies between 50 and 200 MeV nor the Fermi-LAT EGB spectrum at energies above approx. few GeV.

  19. 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

  20. Gravitational Lensing in the metric theory proposed by Sobouti

    Science.gov (United States)

    Bernal, Tula; Mendoza, Sergio

    2008-12-01

    Recently, Y. Sobouti (2007) has provided a metric theory f(R) that can account for certain dynamical anomalies observed in spiral galaxies. Mendoza & Rosas-Guevara (2007) have shown that in this theory there is an extra-bending as compared to standard general relativity. In the present work we have developed in more specific detail this additional lensing effect and we have made evaluations of the α parameter used in the model adjusting the theory to observations in X-rays of 13 clusters of galaxies with gravitational lensing ([6]).

  1. Constraining unified dark matter models with weak lensing

    Energy Technology Data Exchange (ETDEWEB)

    Camera, S. [Dipartimento di Fisica Generale Amedeo Avogadro, Universita degli Studi di Torino, Torino (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Torino, Torino (Italy)

    2010-04-15

    Unified Dark Matter (UDM) models provide an intriguing alternative to Dark Matter (DM) and Dark Energy (DE) through only one exotic component, i.e. a classical scalar field {phi}(t,x). Thanks to a non-canonical kinetic term, this scalar field can mimic both the behaviour of the matter-dominated era at earlier times, as DM do, and the outcoming late-time acceleration, as a cosmological constant DE. Thus, it has been shown that these models can reproduce the same expansion history of the {lambda}CDM concordance model. In this work I review the first prediction of a physical observable, the power spectrum of the weak lensing cosmic convergence (shear). I present the weak lensing signal as predicted by the standard {lambda}CDM model and by a family of viable UDM models parameterized by the late-time sound speed c{sub {infinity}} of the scalar field.last-scattering surface and a series of background galaxies peaked at different redshifts and spread over different redshifts as described by a functional form of their distribution of sources. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  2. GALAXY HALO TRUNCATION AND GIANT ARC SURFACE BRIGHTNESS RECONSTRUCTION IN THE CLUSTER MACSJ1206.2-0847

    International Nuclear Information System (INIS)

    Eichner, Thomas; Seitz, Stella; Monna, Anna; Suyu, Sherry H.; Halkola, Aleksi; Umetsu, Keiichi; Zitrin, Adi; Coe, Dan; Postman, Marc; Koekemoer, Anton; Bradley, Larry; Rosati, Piero; Grillo, Claudio; Høst, Ole; Balestra, Italo; Zheng, Wei; Lemze, Doron; Broadhurst, Tom; Moustakas, Leonidas; Molino, Alberto

    2013-01-01

    In this work, we analyze the mass distribution of MACSJ1206.2-0847, particularly focusing on the halo properties of its cluster members. The cluster appears relaxed in its X-ray emission, but has a significant amount of intracluster light that is not centrally concentrated, suggesting that galaxy-scale interactions are still ongoing despite the overall relaxed state. The cluster lenses 12 background galaxies into multiple images and one galaxy at z = 1.033 into a giant arc and its counterimage. The multiple image positions and the surface brightness (SFB) distribution of the arc, which is bent around several cluster members, are sensitive to the cluster galaxy halo properties. We model the cluster mass distribution with a Navarro-Frenk-White profile and the galaxy halos with two parameters for the mass normalization and the extent of a reference halo assuming scalings with their observed near-infrared light. We match the multiple image positions at an rms level of 0.''85 and can reconstruct the SFB distribution of the arc in several filters to a remarkable accuracy based on this cluster model. The length scale where the enclosed galaxy halo mass is best constrained is about 5 effective radii—a scale in between those accessible to dynamical and field strong-lensing mass estimates on the one hand and galaxy-galaxy weak-lensing results on the other hand. The velocity dispersion and halo size of a galaxy with m 160W,AB = 19.2 and M B,Vega = –20.7 are σ = 150 km s –1 and r ≈ 26 ± 6 kpc, respectively, indicating that the halos of the cluster galaxies are tidally stripped. We also reconstruct the unlensed source, which is smaller by a factor of ∼5.8 in area, demonstrating the increase in morphological information due to lensing. We conclude that this galaxy likely has star-forming spiral arms with a red (older) central component

  3. 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......-scale temperature anisotropies, detecting a cross-correlation at the 3σ level, as expected because of dark energy in the concordance ΛCDM model....

  4. Weak lensing and cosmological investigation

    CERN Document Server

    Acquaviva, V

    2005-01-01

    In the last few years the scientific community has been dealing with the challenging issue of identifying the dark energy component. We regard weak gravitational lensing as a brand new, and extremely important, tool for cosmological investigation in this field. In fact, the features imprinted on the cosmic microwave background radiation by the lensing from the intervening distribution of matter represent a pretty unbiased estimator, and can thus be used for putting constraints on different dark energy models. This is true in particular for the magnetic-type B-modes of CMB polarization, whose unlensed spectrum at large multipoles (l approximately=1000) is very small even in presence of an amount of gravitational waves as large as currently allowed by the experiments: therefore, on these scales the lensing phenomenon is the only responsible for the observed power, and this signal turns out to be a faithful tracer of the dark energy dynamics. We first recall the formal apparatus of the weak lensing in extended t...

  5. A 2500 deg 2 CMB Lensing Map from Combined South Pole Telescope and Planck Data

    Energy Technology Data Exchange (ETDEWEB)

    Omori, Y.; Chown, R.; Simard, G.; Story, K. T.; Aylor, K.; Baxter, E. J.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Cho, H-M.; Crawford, T. M.; Crites, A. T.; Haan, T. de; Dobbs, M. A.; Everett, W. B.; George, E. M.; Halverson, N. W.; Harrington, N. L.; Holder, G. P.; Hou, Z.; Holzapfel, W. L.; Hrubes, J. D.; Knox, L.; Lee, A. T.; Leitch, E. M.; Luong-Van, D.; Manzotti, A.; Marrone, D. P.; McMahon, J. J.; Meyer, S. S.; Mocanu, L. M.; Mohr, J. J.; Natoli, T.; Padin, S.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Sayre, J. T.; Schaffer, K. K.; Shirokoff, E.; Staniszewski, Z.; Stark, A. A.; Vanderlinde, K.; Vieira, J. D.; Williamson, R.; Zahn, O.

    2017-11-07

    We present a cosmic microwave background (CMB) lensing map produced from a linear combination of South Pole Telescope (SPT) and \\emph{Planck} temperature data. The 150 GHz temperature data from the $2500\\ {\\rm deg}^{2}$ SPT-SZ survey is combined with the \\emph{Planck} 143 GHz data in harmonic space, to obtain a temperature map that has a broader $\\ell$ coverage and less noise than either individual map. Using a quadratic estimator technique on this combined temperature map, we produce a map of the gravitational lensing potential projected along the line of sight. We measure the auto-spectrum of the lensing potential $C_{L}^{\\phi\\phi}$, and compare it to the theoretical prediction for a $\\Lambda$CDM cosmology consistent with the \\emph{Planck} 2015 data set, finding a best-fit amplitude of $0.95_{-0.06}^{+0.06}({\\rm Stat.})\\! _{-0.01}^{+0.01}({\\rm Sys.})$. The null hypothesis of no lensing is rejected at a significance of $24\\,\\sigma$. One important use of such a lensing potential map is in cross-correlations with other dark matter tracers. We demonstrate this cross-correlation in practice by calculating the cross-spectrum, $C_{L}^{\\phi G}$, between the SPT+\\emph{Planck} lensing map and Wide-field Infrared Survey Explorer (\\emph{WISE}) galaxies. We fit $C_{L}^{\\phi G}$ to a power law of the form $p_{L}=a(L/L_{0})^{-b}$ with $a=2.15 \\times 10^{-8}$, $b=1.35$, $L_{0}=490$, and find $\\eta^{\\phi G}=0.94^{+0.04}_{-0.04}$, which is marginally lower, but in good agreement with $\\eta^{\\phi G}=1.00^{+0.02}_{-0.01}$, the best-fit amplitude for the cross-correlation of \\emph{Planck}-2015 CMB lensing and \\emph{WISE} galaxies over $\\sim67\\%$ of the sky. The lensing potential map presented here will be used for cross-correlation studies with the Dark Energy Survey (DES), whose footprint nearly completely covers the SPT $2500\\ {\\rm deg}^2$ field.

  6. CLASH: accurate photometric redshifts with 14 HST bands in massive galaxy cluster cores

    Science.gov (United States)

    Molino, A.; Benítez, N.; Ascaso, B.; Coe, D.; Postman, M.; Jouvel, S.; Host, O.; Lahav, O.; Seitz, S.; Medezinski, E.; Rosati, P.; Schoenell, W.; Koekemoer, A.; Jimenez-Teja, Y.; Broadhurst, T.; Melchior, P.; Balestra, I.; Bartelmann, M.; Bouwens, R.; Bradley, L.; Czakon, N.; Donahue, M.; Ford, H.; Graur, O.; Graves, G.; Grillo, C.; Infante, L.; Jha, S. W.; Kelson, D.; Lazkoz, R.; Lemze, D.; Maoz, D.; Mercurio, A.; Meneghetti, M.; Merten, J.; Moustakas, L.; Nonino, M.; Orgaz, S.; Riess, A.; Rodney, S.; Sayers, J.; Umetsu, K.; Zheng, W.; Zitrin, A.

    2017-09-01

    We present accurate photometric redshifts for galaxies observed by the Cluster Lensing And Supernova survey with Hubble (CLASH). CLASH observed 25 massive galaxy cluster cores with the Hubble Space Telescope in 16 filters spanning 0.2-1.7 μm. Photometry in such crowded fields is challenging. Compared to our previously released catalogues, we make several improvements to the photometry, including smaller apertures, intracluster light subtraction, point spread function matching and empirically measured uncertainties. We further improve the Bayesian photometric redshift estimates by adding a redder elliptical template and by inflating the photometric uncertainties of the brightest galaxies. The resulting photometric redshift accuracies are dz/(1+z) ˜ 0.8, 1.0 and 2.0 per cent for galaxies with I-band F814W AB magnitudes cluster members. We also provide stellar mass estimates. Finally, we include lensing magnification estimates of background galaxies based on our public lens models. Our new catalogue of all 25 CLASH clusters is available via Mikulski Archive for Space Telescopes. The analysis techniques developed here will be useful in other surveys of crowded fields, including the Frontier Fields and surveys carried out with Javalambre-Physics of the Accelerated Universe Astrophysical Survey and James Webb Space Telescope.

  7. SDSS J2222+2745: A GRAVITATIONALLY LENSED SEXTUPLE QUASAR WITH A MAXIMUM IMAGE SEPARATION OF 15.''1 DISCOVERED IN THE SLOAN GIANT ARCS SURVEY

    International Nuclear Information System (INIS)

    Dahle, H.; Groeneboom, N.; Gladders, M. D.; Abramson, L. E.; Sharon, K.; Bayliss, M. B.; Wuyts, E.; Koester, B. P.; Brinckmann, T. E.; Kristensen, M. T.; Lindholmer, M. O.; Nielsen, A.; Krogager, J.-K.; Fynbo, J. P. U.

    2013-01-01

    We report the discovery of a unique gravitational lens system, SDSS J2222+2745, producing five spectroscopically confirmed images of a z s = 2.82 quasar lensed by a foreground galaxy cluster at z l = 0.49. We also present photometric and spectroscopic evidence for a sixth lensed image of the same quasar. The maximum separation between the quasar images is 15.''1. Both the large image separations and the high image multiplicity are in themselves rare among known lensed quasars, and observing the combination of these two factors is an exceptionally unlikely occurrence in present data sets. This is only the third known case of a quasar lensed by a cluster, and the only one with six images. The lens system was discovered in the course of the Sloan Giant Arcs Survey, in which we identify candidate lenses in the Sloan Digital Sky Survey and target these for follow-up and verification with the 2.56 m Nordic Optical Telescope. Multi-band photometry obtained over multiple epochs from 2011 September to 2012 September reveals significant variability at the ∼10%-30% level in some of the quasar images, indicating that measurements of the relative time delay between quasar images will be feasible. In this lens system, we also identify a bright (g = 21.5) giant arc corresponding to a strongly lensed background galaxy at z s = 2.30. We fit parametric models of the lens system, constrained by the redshift and positions of the quasar images and the redshift and position of the giant arc. The predicted time delays between different pairs of quasar images range from ∼100 days to ∼6 yr

  8. Fitting gravitational lenses: truth or delusion

    Science.gov (United States)

    Evans, N. Wyn; Witt, Hans J.

    2003-11-01

    The observables in a strong gravitational lens are usually just the image positions and sometimes the flux ratios. We develop a new and simple algorithm which allows a set of models to be fitted exactly to the observations. Taking our cue from the strong body of evidence that early-type galaxies are close to isothermal, we assume that the lens is scale-free with a flat rotation curve. External shear can be easily included. Our algorithm allows full flexibility regarding the angular structure of the lensing potential. Importantly, all the free parameters enter linearly into the model and so the lens and flux ratio equations can always be solved by straightforward matrix inversion. The models are only restricted by the fact that the surface mass density must be positive. We use this new algorithm to examine some of the claims made for anomalous flux ratios. It has been argued that such anomalies betray the presence of substantial amounts of substructure in the lensing galaxy. We demonstrate by explicit construction that some of the lens systems for which substructure has been claimed can be well fitted by smooth lens models. This is especially the case when the systematic errors in the flux ratios (caused by microlensing or differential extinction) are taken into account. However, there is certainly one system (B1422+231) for which the existing smooth models are definitely inadequate and for which substructure may be implicated. Within a few tens of kpc of the lensing galaxy centre, dynamical friction and tidal disruption are known to be very efficient at dissolving any substructure. Very little substructure is projected within the Einstein radius. The numbers of strong lenses for which substructure is currently being claimed may be so large that this contradicts rather than supports cold dark matter theories.

  9. 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.

  10. Cosmological constraints from weak lensing non-Gaussian statistics

    Science.gov (United States)

    Liu, Jia; Haiman, Zoltan; Petri, Andrea; Hill, James; Hui, Lam; Kratochvil, Jan Michael; May, Morgan

    2016-01-01

    Weak gravitational lensing is one of the most promising techniques to probe dark energy. Our work to date suggests that the information in the nonlinear regime exceeds that in the two-point functions. Using the publicly available data from the 154 deg^2 CFHTLenS survey and a large suite of ray-tracing N-body simulations on a grid of 91 cosmological models, we find that constraints from peak counts are comparable to those from the power spectrum, and somewhat tighter when different smoothing scales are combined.I will also introduce the utility of cross-correlating weak galaxy lensing maps with CMB lensing maps, a technique that will be useful to probe structures at an intermediate redshift of 0.9, as larger weak lensing surveys such as HSC, DES, KiDS, Euclid, and LSST come online. We cross-correlate the CFHTLenS galaxy lensing convergence maps with Planck CMB lensing maps. Our results show two sigma tension with the constraints obtained from the Planck temperature measurements. I will discuss possible sources of the tension, including intrinsic alignments, photo-z uncertainties, masking of tSZ in the CMB maps, and the multiplicative bias.

  11. Irregular Dwarf Galaxy IC 1613

    Science.gov (United States)

    2005-01-01

    Ultraviolet image (left) and visual image (right) of the irregular dwarf galaxy IC 1613. Low surface brightness galaxies, such as IC 1613, are more easily detected in the ultraviolet because of the low background levels compared to visual wavelengths.

  12. 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)

  13. Learning through Different Lenses

    Science.gov (United States)

    Jeweler, Sue; Barnes-Robinson, Linda

    2015-01-01

    When parents and teachers help gifted kids use the metaphor "learning through different lenses," amazing things happen: Horizons open up. Ideas are focused. Thoughts are magnified and clarified. They see the big picture. Metaphoric thinking offers new and exciting ways to see the world. Viewing the world through different lenses provides…

  14. SPT-GMOS: A GEMINI/GMOS-SOUTH SPECTROSCOPIC SURVEY OF GALAXY CLUSTERS IN THE SPT-SZ SURVEY

    International Nuclear Information System (INIS)

    Bayliss, M. B.; Ruel, J.; Stubbs, C. W.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Benson, B. A.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Bleem, L. E.; Bocquet, S.; Brodwin, M.; Capasso, R.; Chiu, I.; Cho, H-M.; Clocchiatti, A.; Crites, A. T.; Haan, T. de

    2016-01-01

    We present the results of SPT-GMOS, a spectroscopic survey with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South. The targets of SPT-GMOS are galaxy clusters identified in the SPT-SZ survey, a millimeter-wave survey of 2500 deg 2 of the southern sky using the South Pole Telescope (SPT). Multi-object spectroscopic observations of 62 SPT-selected galaxy clusters were performed between 2011 January and 2015 December, yielding spectra with radial velocity measurements for 2595 sources. We identify 2243 of these sources as galaxies, and 352 as stars. Of the galaxies, we identify 1579 as members of SPT-SZ galaxy clusters. The primary goal of these observations was to obtain spectra of cluster member galaxies to estimate cluster redshifts and velocity dispersions. We describe the full spectroscopic data set and resulting data products, including galaxy redshifts, cluster redshifts, and velocity dispersions, and measurements of several well-known spectral indices for each galaxy: the equivalent width, W , of [O ii] λλ 3727, 3729 and H- δ , and the 4000 Å break strength, D4000. We use the spectral indices to classify galaxies by spectral type (i.e., passive, post-starburst, star-forming), and we match the spectra against photometric catalogs to characterize spectroscopically observed cluster members as a function of brightness (relative to m ⋆ ). Finally, we report several new measurements of redshifts for ten bright, strongly lensed background galaxies in the cores of eight galaxy clusters. Combining the SPT-GMOS data set with previous spectroscopic follow-up of SPT-SZ galaxy clusters results in spectroscopic measurements for >100 clusters, or ∼20% of the full SPT-SZ sample.

  15. SPT-GMOS: A GEMINI/GMOS-SOUTH SPECTROSCOPIC SURVEY OF GALAXY CLUSTERS IN THE SPT-SZ SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Bayliss, M. B.; Ruel, J.; Stubbs, C. W. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Allen, S. W. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, CA 94305 (United States); Applegate, D. E. [Argelander-Institut für Astronomie, Auf dem Hügel 71, D-53121 Bonn (Germany); Ashby, M. L. N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bautz, M. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Benson, B. A.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Bleem, L. E.; Bocquet, S. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Brodwin, M. [Department of Physics and Astronomy, University of Missouri, 5110 Rockhill Road, Kansas City, MO 64110 (United States); Capasso, R.; Chiu, I. [Faculty of Physics, Ludwig-Maximilians-Universität, Scheinerstr. 1, D-81679 Munich (Germany); Cho, H-M. [NIST Quantum Devices Group, Boulder, CO 80305 (United States); Clocchiatti, A. [Departamento de Astronomia y Astrosifica, Pontificia Universidad Catolica (Chile); Crites, A. T. [California Institute of Technology, Pasadena, CA 91125 (United States); Haan, T. de, E-mail: mbbayliss@cfa.harvard.edu [Department of Physics, University of California, Berkeley, CA 94720 (United States); and others

    2016-11-01

    We present the results of SPT-GMOS, a spectroscopic survey with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South. The targets of SPT-GMOS are galaxy clusters identified in the SPT-SZ survey, a millimeter-wave survey of 2500 deg{sup 2} of the southern sky using the South Pole Telescope (SPT). Multi-object spectroscopic observations of 62 SPT-selected galaxy clusters were performed between 2011 January and 2015 December, yielding spectra with radial velocity measurements for 2595 sources. We identify 2243 of these sources as galaxies, and 352 as stars. Of the galaxies, we identify 1579 as members of SPT-SZ galaxy clusters. The primary goal of these observations was to obtain spectra of cluster member galaxies to estimate cluster redshifts and velocity dispersions. We describe the full spectroscopic data set and resulting data products, including galaxy redshifts, cluster redshifts, and velocity dispersions, and measurements of several well-known spectral indices for each galaxy: the equivalent width, W , of [O ii] λλ 3727, 3729 and H- δ , and the 4000 Å break strength, D4000. We use the spectral indices to classify galaxies by spectral type (i.e., passive, post-starburst, star-forming), and we match the spectra against photometric catalogs to characterize spectroscopically observed cluster members as a function of brightness (relative to m {sup ⋆}). Finally, we report several new measurements of redshifts for ten bright, strongly lensed background galaxies in the cores of eight galaxy clusters. Combining the SPT-GMOS data set with previous spectroscopic follow-up of SPT-SZ galaxy clusters results in spectroscopic measurements for >100 clusters, or ∼20% of the full SPT-SZ sample.

  16. iPTF16geu: A multiply imaged, gravitationally lensed type Ia supernova.

    Science.gov (United States)

    Goobar, A; Amanullah, R; Kulkarni, S R; Nugent, P E; Johansson, J; Steidel, C; Law, D; Mörtsell, E; Quimby, R; Blagorodnova, N; Brandeker, A; Cao, Y; Cooray, A; Ferretti, R; Fremling, C; Hangard, L; Kasliwal, M; Kupfer, T; Lunnan, R; Masci, F; Miller, A A; Nayyeri, H; Neill, J D; Ofek, E O; Papadogiannakis, S; Petrushevska, T; Ravi, V; Sollerman, J; Sullivan, M; Taddia, F; Walters, R; Wilson, D; Yan, L; Yaron, O

    2017-04-21

    We report the discovery of a multiply imaged, gravitationally lensed type Ia supernova, iPTF16geu (SN 2016geu), at redshift z = 0.409. This phenomenon was identified because the light from the stellar explosion was magnified more than 50 times by the curvature of space around matter in an intervening galaxy. We used high-spatial-resolution observations to resolve four images of the lensed supernova, approximately 0.3 arc seconds from the center of the foreground galaxy. The observations probe a physical scale of ~1 kiloparsec, smaller than is typical in other studies of extragalactic gravitational lensing. The large magnification and symmetric image configuration imply close alignment between the lines of sight to the supernova and to the lens. The relative magnifications of the four images provide evidence for substructures in the lensing galaxy. Copyright © 2017, American Association for the Advancement of Science.

  17. 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.

  18. Class B0631+519: Last of the Class Lenses

    Energy Technology Data Exchange (ETDEWEB)

    York, Tom; Jackson, N.; Browne, I.W.A.; Koopmans, L.V.E.; McKean, J.P.; Norbury, M.A.; Biggs, A.D.; Blandford, R.D.; de Bruyn, A.G.; Fassnacht, C.D.; Myers, S.T.; Pearson, T.J.; Phillips, P.M.; Readhead, A.C.S.; Rusin, D.; Wilkinson, P.N.; /Jodrell Bank /Kapteyn Astron. Inst., Groningen /UC, Davis /JIVE, Dwingeloo /KIPAC, Menlo Park /NFRA,

    2005-05-31

    We report the discovery of the new gravitational lens system CLASS B0631+519. Imaging with the VLA, MERLIN and the VLBA reveals a doubly-imaged flat-spectrum radio core, a doubly-imaged steep-spectrum radio lobe and possible quadruply-imaged emission from a second lobe. The maximum separation between the lensed images is 1.16 arcsec. High resolution mapping with the VLBA at 5 GHz resolves the most magnified image of the radio core into a number of sub-components spread across approximately 20 mas. No emission from the lensing galaxy or an odd image is detected down to 0.31 mJy (5{sigma}) at 8.4 GHz. Optical and near-infrared imaging with the ACS and NICMOS cameras on the HST show that there are two galaxies along the line of sight to the lensed source, as previously discovered by optical spectroscopy. We find that the foreground galaxy at z=0.0896 is a small irregular, and that the other, at z=0.6196 is a massive elliptical which appears to contribute the majority of the lensing effect. The host galaxy of the lensed source is detected in the HST near-infrared imaging as a set of arcs, which form a nearly complete Einstein ring. Mass modeling using non-parametric techniques can reproduce the near-infrared observations and indicates that the small irregular galaxy has a (localized) effect on the flux density distribution in the Einstein ring at the 5-10% level.

  19. A gravitationally lensed quasar with quadruple images separated by 14.62 arcseconds.

    Science.gov (United States)

    Inada, Naohisa; Oguri, Masamune; Pindor, Bartosz; Hennawi, Joseph F; Chiu, Kuenley; Zheng, Wei; Ichikawa, Shin-Ichi; Gregg, Michael D; Becker, Robert H; Suto, Yasushi; Strauss, Michael A; Turner, Edwin L; Keeton, Charles R; Annis, James; Castander, Francisco J; Eisenstein, Daniel J; Frieman, Joshua A; Fukugita, Masataka; Gunn, James E; Johnston, David E; Kent, Stephen M; Nichol, Robert C; Richards, Gordon T; Rix, Hans-Walter; Sheldon, Erin Scott; Bahcall, Neta A; Brinkmann, J; Ivezić, Zeljko; Lamb, Don Q; McKay, Timothy A; Schneider, Donald P; York, Donald G

    2003-12-18

    Gravitational lensing is a powerful tool for the study of the distribution of dark matter in the Universe. The cold-dark-matter model of the formation of large-scale structures (that is, clusters of galaxies and even larger assemblies) predicts the existence of quasars gravitationally lensed by concentrations of dark matter so massive that the quasar images would be split by over 7 arcsec. Numerous searches for large-separation lensed quasars have, however, been unsuccessful. All of the roughly 70 lensed quasars known, including the first lensed quasar discovered, have smaller separations that can be explained in terms of galaxy-scale concentrations of baryonic matter. Although gravitationally lensed galaxies with large separations are known, quasars are more useful cosmological probes because of the simplicity of the resulting lens systems. Here we report the discovery of a lensed quasar, SDSS J1004 + 4112, which has a maximum separation between the components of 14.62 arcsec. Such a large separation means that the lensing object must be dominated by dark matter. Our results are fully consistent with theoretical expectations based on the cold-dark-matter model.

  20. Meso-Structure in Three Strong-lensing Systems

    Science.gov (United States)

    Saha, Prasenjit; Williams, Liliya L. R.; Ferreras, Ignacio

    2007-07-01

    We map substructure in three strong-lensing systems having particularly good image data: the galaxy lens MG J0414+053 and the clusters SDSS J1004+411 and ACO 1689. Our method is to first reconstruct the lens as a pixelated mass map and then subtract off the symmetric part (in the galaxy case) or a projected Navarro-Frenk-White profile (for the cluster lenses). In all three systems we find extended irregular structures, or meso-structures, having of order 10% of the total mass. In J0414+053, the meso-structure suggests a tidal tail connecting the main lens with a nearby galaxy; however, this interpretation is tentative. In the clusters, the identification of meso-structure is more secure, especially in ACO 1689, where two independent sets of lensed images imply very similar meso-structure. In all three cases, the meso-structures are correlated with galaxies but much more extended and massive than the stellar components of single galaxies. Such extended structures cannot plausibly persist in such high-density regions without being mixed; the crossing times are too short. The meso-structures therefore appear to be merging or otherwise dynamically evolving systems.

  1. Kiloparsec Mass/Light Offsets in the Galaxy Pair-Lyα Emitter Lens System SDSS J1011+0143

    Science.gov (United States)

    Shu, Yiping; Bolton, Adam S.; Moustakas, Leonidas A.; Stern, Daniel; Dey, Arjun; Brownstein, Joel R.; Burles, Scott; Spinrad, Hyron

    2016-03-01

    We report the discovery of significant mass/light offsets in the strong gravitational lensing system SDSS J1011+0143. We use the high-resolution Hubble Space Telescope (HST) F555W- and F814W-band imaging and Sloan Digital Sky Survey (SDSS) spectroscopy of this system, which consists of a close galaxy pair with a projected separation of ≈ 4.2 {{kpc}} at zlens ˜ 0.331 lensing an Lyα emitter (LAE) at zsource = 2.701. Comparisons between the mass peaks inferred from lens models and light peaks from HST imaging data reveal significant spatial mass/light offsets as large as 1.72 ± 0.24 ± 0.34 kpc in both filter bands. Such large mass/light offsets, not seen in isolated field lens galaxies and relaxed galaxy groups, may be related to the interactions between the two lens galaxies. The detected mass/light offsets can potentially serve as an important test for the self-interacting dark matter model. However, other mechanisms such as dynamical friction on spatially differently distributed dark matter and stars could produce similar offsets. Detailed hydrodynamical simulations of galaxy-galaxy interactions with self-interacting dark matter could accurately quantify the effects of different mechanisms. The background LAE is found to contain three distinct star-forming knots with characteristic sizes from 116 to 438 pc. It highlights the power of strong gravitational lensing in probing the otherwise too faint and unresolved structures of distance objects below subkiloparsec or even 100 pc scales through its magnification effect. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. These observations are associated with program #10831.

  2. The origin of galaxies

    International Nuclear Information System (INIS)

    Carr, B.J.

    1982-01-01

    The existence of galaxies implies that the early Universe must have contained initial density fluctuations. Overdense regions would then expand more slowly than the background and eventually - providing the fluctuations were not damped out first - they would stop expanding altogether and collapse to form bound objects. To understand how galaxies form we therefore need to know: how the initial density fluctuations arise, under what circumstances they evolve into bound objects, and how the bound objects develop the observed characteristics of galaxies. (author)

  3. Inverting Gravitational Lenses

    Science.gov (United States)

    Newbury, P. R.; Spiteri, R. J.

    2002-02-01

    Gravitational lensing provides a powerful tool to study a number of fundamental questions in astrophysics. Fortuitously, one can begin to explore some non-trivial issues associated with this phenomenon without a lot of very sophisticated mathematics, making an elementary treatment of this topic tractable even to senior undergraduates. In this paper, we give a relatively self-contained outline of the basic concepts and mathematics behind gravitational lensing as a recent and exciting topic for courses in mathematical modeling or scientific computing. To this end, we have designed and made available some interactive software to aid in the simulation and inversion of gravitational lenses in a classroom setting.

  4. Stress-Detection Lenses

    Science.gov (United States)

    1996-01-01

    An Ames Research Center scientist invented an infrared lens used in sunglasses to filter out ultraviolet rays. This product finds its origins in research for military enemy detection. Through a Space Act Agreement, Optical Sales Corporation introduced the Hawkeye Lenses not only as sunglasses but as plant stress detection lenses. The lenses enhance the stressed part of the leaf, which has less chlorophyll than healthy leaves, through dyes that filter out certain wavelengths of light. Plant stress is visible earlier, at a stage when something can be done to save the plants.

  5. Mass Models and Environment of the New Quadruply Lensed Quasar SDSS J1330+1810

    Energy Technology Data Exchange (ETDEWEB)

    Oguri, Masamune; Inada, Naohisa; Blackburne, Jeffrey A.; Shin, Min-Su; Kayo, Issha; Strauss, Michael A.; Schneider, Donald P.; York, Donald G.

    2008-09-09

    We present the discovery of a new quadruply lensed quasar. The lens system, SDSS J1330+1810 at z{sub s} = 1.393, was identified as a lens candidate from the spectroscopic sample of the Sloan Digital Sky Survey. Optical and near-infrared images clearly show four quasar images with a maximum image separation of 1.76 inch, as well as a bright lensing galaxy. We measure a redshift of the lensing galaxy of z{sub 1} = 0.373 from absorption features in the spectrum. We find a foreground group of galaxies at z = 0.31 centred {approx} 120 inch southwest of the lens system. Simple mass models fit the data quite well, including the flux ratios between images, although the lens galaxy appears to be {approx} 1 mag brighter than expected by the Faber-Jackson relation. Our mass modeling suggests that shear from nearby structure is affecting the lens potential.

  6. Weak lensing magnification in the Dark Energy Survey Science Verification data

    Science.gov (United States)

    Garcia-Fernandez, M.; Sanchez, E.; Sevilla-Noarbe, I.; Suchyta, E.; Huff, E. M.; Gaztanaga, E.; Aleksić, J.; Ponce, R.; Castander, F. J.; Hoyle, B.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Eifler, T. F.; Evrard, A. E.; Fernandez, E.; Flaugher, B.; Fosalba, P.; Frieman, J.; García-Bellido, J.; Gerdes, D. W.; Giannantonio, T.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; James, D. J.; Jarvis, M.; Kirk, D.; Krause, E.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; MacCrann, N.; Maia, M. A. G.; March, M.; Marshall, J. L.; Melchior, P.; Miquel, R.; Mohr, J. J.; Plazas, A. A.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Scarpine, V.; Schubnell, M.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Tarle, G.; Thomas, D.; Walker, A. R.; Wester, W.

    2018-02-01

    In this paper the effect of weak lensing magnification on galaxy number counts is studied by cross-correlating the positions of two galaxy samples, separated by redshift, using the Dark Energy Survey Science Verification dataset. This analysis is carried out for galaxies that are selected only by its photometric redshift. An extensive analysis of the systematic effects, using new methods based on simulations is performed, including a Monte Carlo sampling of the selection function of the survey.

  7. Weak lensing magnification in the Dark Energy Survey Science Verification data

    Science.gov (United States)

    Garcia-Fernandez, M.; Sanchez, E.; Sevilla-Noarbe, I.; Suchyta, E.; Huff, E. M.; Gaztanaga, E.; Aleksić, J.; Ponce, R.; Castander, F. J.; Hoyle, B.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Eifler, T. F.; Evrard, A. E.; Fernandez, E.; Flaugher, B.; Fosalba, P.; Frieman, J.; García-Bellido, J.; Gerdes, D. W.; Giannantonio, T.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; James, D. J.; Jarvis, M.; Kirk, D.; Krause, E.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; MacCrann, N.; Maia, M. A. G.; March, M.; Marshall, J. L.; Melchior, P.; Miquel, R.; Mohr, J. J.; Plazas, A. A.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Scarpine, V.; Schubnell, M.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Tarle, G.; Thomas, D.; Walker, A. R.; Wester, W.; DES Collaboration

    2018-05-01

    In this paper, the effect of weak lensing magnification on galaxy number counts is studied by cross-correlating the positions of two galaxy samples, separated by redshift, using the Dark Energy Survey Science Verification data set. This analysis is carried out for galaxies that are selected only by its photometric redshift. An extensive analysis of the systematic effects, using new methods based on simulations is performed, including a Monte Carlo sampling of the selection function of the survey.

  8. 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

  9. The Cambridge photographic atlas of galaxies

    CERN Document Server

    König, Michael

    2017-01-01

    Galaxies - the Milky Way's siblings - offer a surprising variety of forms and colours. Displaying symmetrical spiral arms, glowing red nebulae or diffuse halos, even the image of a galaxy can reveal much about its construction. All galaxies consist of gas, dust and stars, but the effects of gravity, dark matter and the interaction of star formation and stellar explosions all influence their appearances. This volume showcases more than 250 of the most beautiful galaxies within an amateur's reach and uses them to explain current astrophysical research. It features fantastic photographs, unique insights into our knowledge, tips on astrophotography and essential facts and figures based on the latest science. From the Andromeda Galaxy to galaxy clusters and gravitational lenses, the nature of galaxies is revealed through these stunning amateur photographs. This well illustrated reference atlas deserves a place on the bookshelves of astronomical imagers, observers and armchair enthusiasts.

  10. 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.

  11. CMB-lensing beyond the Born approximation

    International Nuclear Information System (INIS)

    Marozzi, Giovanni; Fanizza, Giuseppe; Durrer, Ruth; Dio, Enea Di

    2016-01-01

    We investigate the weak lensing corrections to the cosmic microwave background temperature anisotropies considering effects beyond the Born approximation. To this aim, we use the small deflection angle approximation, to connect the lensed and unlensed power spectra, via expressions for the deflection angles up to third order in the gravitational potential. While the small deflection angle approximation has the drawback to be reliable only for multipoles ℓ ∼< 2500, it allows us to consistently take into account the non-Gaussian nature of cosmological perturbation theory beyond the linear level. The contribution to the lensed temperature power spectrum coming from the non-Gaussian nature of the deflection angle at higher order is a new effect which has not been taken into account in the literature so far. It turns out to be the leading contribution among the post-Born lensing corrections. On the other hand, the effect is smaller than corrections coming from non-linearities in the matter power spectrum, and its imprint on CMB lensing is too small to be seen in present experiments.

  12. THE YUAN-TSEH LEE ARRAY FOR MICROWAVE BACKGROUND ANISOTROPY

    International Nuclear Information System (INIS)

    Ho, Paul T. P.; Altamirano, Pablo; Chang, C.-H.; Chang, S.-H.; Chang, S.-W.; Chen, C.-C.; Chen, K.-J.; Chen, M.-T.; Han, C.-C.; Ho, West M.; Huang, Y.-D.; Hwang, Y.-J.; Ibanez-Romano, Fabiola; Jiang Homin; Koch, Patrick M.; Kubo, Derek Y.; Li, C.-T.; Lim, Jeremy; Lin, K.-Y.; Liu, G.-C.

    2009-01-01

    The Yuan-Tseh Lee Array for microwave background anisotropy is the first interferometer dedicated to study the cosmic microwave background radiation at 3 mm wavelength. The choice of 3 mm is to minimize the contributions from foreground synchrotron radiation and Galactic dust emission. The initial configuration of seven 0.6 m telescopes mounted on a 6 m hexapod platform was dedicated in 2006 October on Mauna Loa, Hawaii. Scientific operations began with the detection of a number of clusters of galaxies via the thermal Sunyaev-Zel'dovich effect. We compare our data with Subaru weak-lensing data to study the structure of dark matter. We also compare our data with X-ray data to derive the Hubble constant.

  13. Observational constraints on Chaplygin quartessence: Background results

    International Nuclear Information System (INIS)

    Makler, Martin; Quinet de Oliveira, Sergio; Waga, Ioav

    2003-01-01

    We derive the constraints set by several experiments on the quartessence Chaplygin model (QCM). In this scenario, a single fluid component drives the Universe from a nonrelativistic matter-dominated phase to an accelerated expansion phase behaving, first, like dark matter and in a more recent epoch like dark energy. We consider current data from SNIa experiments, statistics of gravitational lensing, FR IIb radio galaxies, and x-ray gas mass fraction in galaxy clusters. We investigate the constraints from this data set on flat Chaplygin quartessence cosmologies. The observables considered here are dependent essentially on the background geometry, and not on the specific form of the QCM fluctuations. We obtain the confidence region on the two parameters of the model from a combined analysis of all the above tests. We find that the best fit occurs close to the ΛCDM limit (α=0). The standard Chaplygin quartessence (α=1) is also allowed by the data, but only at the ∼2σ level

  14. Precision cluster mass determination from weak lensing

    Science.gov (United States)

    Mandelbaum, Rachel; Seljak, Uroš; Baldauf, Tobias; Smith, Robert E.

    2010-07-01

    Weak gravitational lensing has been used extensively in the past decade to constrain the masses of galaxy clusters, and is the most promising observational technique for providing the mass calibration necessary for precision cosmology with clusters. There are several challenges in estimating cluster masses, particularly (a) the sensitivity to astrophysical effects and observational systematics that modify the signal relative to the theoretical expectations, and (b) biases that can arise due to assumptions in the mass estimation method, such as the assumed radial profile of the cluster. All of these challenges are more problematic in the inner regions of the cluster, suggesting that their influence would ideally be suppressed for the purpose of mass estimation. However, at any given radius the differential surface density measured by lensing is sensitive to all mass within that radius, and the corrupted signal from the inner parts is spread out to all scales. We develop a new statistic Υ(RR0) that is ideal for estimation of cluster masses because it completely eliminates mass contributions below a chosen scale (which we suggest should be about 20 per cent of the virial radius), and thus reduces sensitivity to systematic and astrophysical effects. We use simulated and analytical profiles including shape noise to quantify systematic biases on the estimated masses for several standard methods of mass estimation, finding that these can lead to significant mass biases that range from 10 to over 50 per cent. The mass uncertainties when using the new statistic Υ(RR0) are reduced by up to a factor of 10 relative to the standard methods, while only moderately increasing the statistical errors. This new method of mass estimation will enable a higher level of precision in future science work with weak lensing mass estimates for galaxy clusters.

  15. Golden Gravitational Lensing Systems from the Sloan Lens ACS Survey. I. SDSS J1538+5817: One Lens for Two Sources

    Science.gov (United States)

    Grillo, C.; Eichner, T.; Seitz, S.; Bender, R.; Lombardi, M.; Gobat, R.; Bauer, A.

    2010-02-01

    We present a gravitational lensing and photometric study of the exceptional strong lensing system SDSS J1538+5817, identified by the Sloan Lens Advanced Camera for Survey. The lens is a luminous elliptical galaxy at redshift zl = 0.143. Using Hubble Space Telescope public images obtained with two different filters, the presence of two background sources lensed, respectively, into an Einstein ring and a double system is ascertained. Our new spectroscopic observations, performed at the Nordic Optical Telescope, reveal unequivocally that the two sources are located at the same redshift zs = 0.531. We investigate the total (luminous and dark) mass distribution of the lens between 1 and 4 kpc from the galaxy center by means of parametric and non-parametric lensing codes that describe the multiple images as point-like objects. Bootstrapping and Bayesian analyses are performed to determine the uncertainties on the quantities relevant to the lens mass characterization. Several disparate lensing models provide results that are consistent, given the errors, with those obtained from the best-fit model of the lens mass distribution in terms of a singular power-law ellipsoid model. In particular, the lensing models agree on: (1) reproducing accurately the observed positions of the images; (2) predicting a nearly axisymmetric total mass distribution, centered and oriented as the light distribution; (3) measuring a value of 8.11+0.27 -0.59 × 1010 M sun for the total mass projected within the Einstein radius of 2.5 kpc; and (4) estimating a total mass density profile slightly steeper than an isothermal one (ρ (r) ∝ r^{-2.33^{+0.43}_{-0.20}}). A fit of the Sloan Digital Sky Survey multicolor photometry with composite stellar population models provides a value of 20+1 -4 × 1010 M sun for the total mass of the galaxy in the form of stars and of 0.9+0.1 -0.2 for the fraction of projected luminous over total mass enclosed inside the Einstein radius. By combining lensing (total

  16. FERMI/LAT OBSERVATIONS OF SWIFT/BAT SEYFERT GALAXIES: ON THE CONTRIBUTION OF RADIO-QUIET ACTIVE GALACTIC NUCLEI TO THE EXTRAGALACTIC γ-RAY BACKGROUND

    International Nuclear Information System (INIS)

    Teng, Stacy H.; Mushotzky, Richard F.; Reynolds, Christopher S.; Sambruna, Rita M.; Davis, David S.

    2011-01-01

    We present the analysis of 2.1 years of Fermi Large Area Telescope (LAT) data on 491 Seyfert galaxies detected by the Swift Burst Alert Telescope (BAT) survey. Only the two nearest objects, NGC 1068 and NGC 4945, which were identified in the Fermi first year catalog, are detected. Using Swift/BAT and radio 20 cm fluxes, we define a new radio-loudness parameter R X,BAT where radio-loud objects have log R X,BAT > –4.7. Based on this parameter, only radio-loud sources are detected by Fermi/LAT. An upper limit to the flux of the undetected sources is derived to be ∼2 × 10 –11 photons cm –2 s –1 , approximately seven times lower than the observed flux of NGC 1068. Assuming a median redshift of 0.031, this implies an upper limit to the γ-ray (1-100 GeV) luminosity of ∼ 41 erg s –1 . In addition, we identified 120 new Fermi/LAT sources near the Swift/BAT Seyfert galaxies with significant Fermi/LAT detections. A majority of these objects do not have Swift/BAT counterparts, but their possible optical counterparts include blazars, flat-spectrum radio quasars, and quasars.

  17. Fermi/LAT Observations of Swift/BAT Seyfert Galaxies: On the Contribution of Radio-Quiet Active Galactic Nuclei to the Extragalactic gamma-Ray Background

    Science.gov (United States)

    Teng, Stacy H.; Mushotzky, Richard F.; Sambruna, Rita M.; Davis, David S.; Reynolds, Christopher S.

    2011-01-01

    We present the analysis of 2.1 years of Fermi Large Area Telescope (LAT) data on 491 Seyfert galaxies detected by the Swift Burst Alert Telescope (BAT) survey. Only the two nearest objects, NGC 1068 and NGC 4945, which were identified in the Fermi first year catalog, are detected. Using Swift/BAT and radio 20 cm fluxes, we define a new radio-loudness parameter R(sub X,BAT) where radio-loud objects have logR(sub X,BAT) > -4.7. Based on this parameter, only radio-loud sources are detected by Fermi/LAT. An upper limit to the flux of the undetected sources is derived to be approx.2x10(exp -11) photons/sq cm/s, approximately seven times lower than the observed flux of NGC 1068. Assuming a median redshift of 0.031, this implies an upper limit to the gamma-ray (1-100 GeV) luminosity of BAT Seyfert galaxies with significant Fermi/LAT detections. A majority of these objects do not have Swift/BAT counterparts, but their possible optical counterparts include blazars, flat-spectrum radio quasars, and quasars.

  18. Modelling Baryonic Effects on Galaxy Cluster Mass Profiles

    Science.gov (United States)

    Shirasaki, Masato; Lau, Erwin T.; Nagai, Daisuke

    2018-03-01

    Gravitational lensing is a powerful probe of the mass distribution of galaxy clusters and cosmology. However, accurate measurements of the cluster mass profiles are limited by uncertainties in cluster astrophysics. In this work, we present a physically motivated model of baryonic effects on the cluster mass profiles, which self-consistently takes into account the impact of baryons on the concentration as well as mass accretion histories of galaxy clusters. We calibrate this model using the Omega500 hydrodynamical cosmological simulations of galaxy clusters with varying baryonic physics. Our model will enable us to simultaneously constrain cluster mass, concentration, and cosmological parameters using stacked weak lensing measurements from upcoming optical cluster surveys.

  19. 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.

  20. Gravitational Lensing as a Probe of Cold Dark Matter Subhalos

    Directory of Open Access Journals (Sweden)

    Erik Zackrisson

    2010-01-01

    Full Text Available In the cold dark matter scenario, dark matter halos are assembled hierarchically from smaller subunits. Some of these subunits are disrupted during the merging process, whereas others survive temporarily in the form of subhalos. A long-standing problem with this picture is that the number of subhalos predicted by simulations exceeds the number of luminous dwarf galaxies seen in the vicinity of large galaxies like the Milky Way. Many of the subhalos must therefore have remained dark or very faint. If cold dark matter subhalos are as common as predicted, gravitational lensing may in principle offer a promising route to detection. In this paper, we describe the many ways through which lensing by subhalos can manifest itself, and summarize the results from current efforts to constrain the properties of cold dark matter subhalos using such effects.

  1. Detection of brown dwarfs by the micro-lensing of unresolved stars

    CERN Document Server

    Baillon, Paul; Giraud-Héraud, Yannick; Kaplan, J; Baillon, Paul; Bouquet, Alain; Giraud-Héraud, Yannick; Kaplan, Jean

    1993-01-01

    The presence of brown dwarfs in the dark galactic halo could be detected through their gravitational lensing effect and experiments under way monitor about one million stars to observe a few lensing events per year. We show that if the photon flux from a galaxy is measured with a good precision, it is not necessary to resolve the stars and besides more events could be observed.

  2. 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.

  3. The LAMOST survey of background quasars in the vicinity of the Andromeda and Triangulum galaxies. II. Results from the commissioning observations and the pilot surveys

    Energy Technology Data Exchange (ETDEWEB)

    Huo, Zhi-Ying; Bai, Zhong-Rui; Chen, Jian-Jun; Chen, Xiao-Yan; Du, Bing; Jia, Lei; Lei, Ya-Juan [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Liu, Xiao-Wei; Yuan, Hai-Bo [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Xiang, Mao-Sheng; Huang, Yang; Zhang, Hui-Hua [Department of Astronomy, Peking University, Beijing 100871 (China); Yan, Lin [Infrared Processing and Analysis Center, California Institute of Technology, MS 100-22, Pasadena, CA 91125 (United States); Chu, Jia-Ru; Chu, Yao-Quan; Hu, Hong-Zhuan [University of Science and Technology of China, Hefei 230026 (China); Cui, Xiang-Qun; Hou, Yong-Hui; Hu, Zhong-Wen; Jiang, Fang-Hua, E-mail: zhiyinghuo@bao.ac.cn [Nanjing Institute of Astronomical Optics and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Nanjing 210042 (China); and others

    2013-06-01

    We present new quasars discovered in the vicinity of the Andromeda and Triangulum galaxies with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, also named the Guoshoujing Telescope, during the 2010 and 2011 observational seasons. Quasar candidates are selected based on the available Sloan Digital Sky Survey, Kitt Peak National Observatory 4 m telescope, Xuyi Schmidt Telescope Photometric Survey optical, and Wide-field Infrared Survey Explorer near-infrared photometric data. We present 509 new quasars discovered in a stripe of ∼135 deg{sup 2} from M31 to M33 along the Giant Stellar Stream in the 2011 pilot survey data sets, and also 17 new quasars discovered in an area of ∼100 deg{sup 2} that covers the central region and the southeastern halo of M31 in the 2010 commissioning data sets. These 526 new quasars have i magnitudes ranging from 15.5 to 20.0, redshifts from 0.1 to 3.2. They represent a significant increase of the number of identified quasars in the vicinity of M31 and M33. There are now 26, 62, and 139 known quasars in this region of the sky with i magnitudes brighter than 17.0, 17.5, and 18.0, respectively, of which 5, 20, and 75 are newly discovered. These bright quasars provide an invaluable collection with which to probe the kinematics and chemistry of the interstellar/intergalactic medium in the Local Group of galaxies. A total of 93 quasars are now known with locations within 2.°5 of M31, of which 73 are newly discovered. Tens of quasars are now known to be located behind the Giant Stellar Stream, and hundreds are behind the extended halo and its associated substructures of M31. The much enlarged sample of known quasars in the vicinity of M31 and M33 can potentially be utilized to construct a perfect astrometric reference frame to measure the minute proper motions (PMs) of M31 and M33, along with the PMs of substructures associated with the Local Group of galaxies. Those PMs are some of the most fundamental properties of the Local

  4. Biocompatibility of Intraocular Lenses.

    Science.gov (United States)

    Özyol, Pelin; Özyol, Erhan; Karel, Fatih

    2017-08-01

    The performance of an intraocular lens is determined by several factors such as the surgical technique, surgical complications, intraocular lens biomaterial and design, and host reaction to the lens. The factor indicating the biocompatibility of an intraocular lens is the behavior of inflammatory and lens epithelial cells. Hence, the biocompatibility of intraocular lens materials is assessed in terms of uveal biocompatibility, based on the inflammatory foreign-body reaction of the eye against the implant, and in terms of capsular biocompatibility, determined by the relationship of the intraocular lens with residual lens epithelial cells within the capsular bag. Insufficient biocompatibility of intraocular lens materials may result in different clinical entities such as anterior capsule opacification, posterior capsule opacification, and lens epithelial cell ongrowth. Intraocular lenses are increasingly implanted much earlier in life in cases such as refractive lens exchange or pediatric intraocular lens implantation after congenital cataract surgery, and these lenses are expected to exhibit maximum performance for many decades. The materials used in intraocular lens manufacture should, therefore, ensure long-term uveal and capsular biocompatibility. In this article, we review the currently available materials used in the manufacture of intraocular lenses, especially with regard to their uveal and capsular biocompatibility, and discuss efforts to improve the biocompatibility of intraocular lenses.

  5. THE THIRD GRAVITATIONAL LENSING ACCURACY TESTING (GREAT3) CHALLENGE HANDBOOK

    International Nuclear Information System (INIS)

    Mandelbaum, Rachel; Kannawadi, Arun; Simet, Melanie; Rowe, Barnaby; Kacprzak, Tomasz; Bosch, James; Miyatake, Hironao; Chang, Chihway; Gill, Mandeep; Courbin, Frederic; Jarvis, Mike; Armstrong, Bob; Lackner, Claire; Leauthaud, Alexie; Nakajima, Reiko; Rhodes, Jason; Zuntz, Joe; Bridle, Sarah; Coupon, Jean; Dietrich, Jörg P.

    2014-01-01

    The GRavitational lEnsing Accuracy Testing 3 (GREAT3) challenge is the third in a series of image analysis challenges, with a goal of testing and facilitating the development of methods for analyzing astronomical images that will be used to measure weak gravitational lensing. This measurement requires extremely precise estimation of very small galaxy shape distortions, in the presence of far larger intrinsic galaxy shapes and distortions due to the blurring kernel caused by the atmosphere, telescope optics, and instrumental effects. The GREAT3 challenge is posed to the astronomy, machine learning, and statistics communities, and includes tests of three specific effects that are of immediate relevance to upcoming weak lensing surveys, two of which have never been tested in a community challenge before. These effects include many novel aspects including realistically complex galaxy models based on high-resolution imaging from space; a spatially varying, physically motivated blurring kernel; and a combination of multiple different exposures. To facilitate entry by people new to the field, and for use as a diagnostic tool, the simulation software for the challenge is publicly available, though the exact parameters used for the challenge are blinded. Sample scripts to analyze the challenge data using existing methods will also be provided. See http://great3challenge.info and http://great3.projects.phys.ucl.ac.uk/leaderboard/ for more information

  6. Subaru weak-lensing survey of dark matter subhalos in the Coma cluster: Subhalo mass function and statistical properties

    Energy Technology Data Exchange (ETDEWEB)

    Okabe, Nobuhiro [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Futamase, Toshifumi; Kuroshima, Risa [Astronomical Institute, Tohoku University, Sendai 980-8578 (Japan); Kajisawa, Masaru, E-mail: nobuhiro.okabe@ipmu.jp [Research Center for Space and Cosmic Evolution, Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577 (Japan)

    2014-04-01

    We present a 4 deg{sup 2} weak gravitational lensing survey of subhalos in the very nearby Coma cluster using the Subaru/Suprime-Cam. The large apparent size of cluster subhalos allows us to measure the mass of 32 subhalos detected in a model-independent manner, down to the order of 10{sup –3} of the virial mass of the cluster. Weak-lensing mass measurements of these shear-selected subhalos enable us to investigate subhalo properties and the correlation between subhalo masses and galaxy luminosities for the first time. The mean distortion profiles stacked over subhalos show a sharply truncated feature which is well-fitted by a Navarro-Frenk-White (NFW) mass model with the truncation radius, as expected due to tidal destruction by the main cluster. We also found that subhalo masses, truncation radii, and mass-to-light ratios decrease toward the cluster center. The subhalo mass function, dn/dln M {sub sub}, in the range of 2 orders of magnitude in mass, is well described by a single power law or a Schechter function. Best-fit power indices of 1.09{sub −0.32}{sup +0.42} for the former model and 0.99{sub −0.23}{sup +0.34} for the latter, are in remarkable agreement with slopes of ∼0.9-1.0 predicted by the cold dark matter paradigm. The tangential distortion signals in the radial range of 0.02-2 h {sup –1} Mpc from the cluster center show a complex structure which is well described by a composition of three mass components of subhalos, the NFW mass distribution as a smooth component of the main cluster, and a lensing model from a large scale structure behind the cluster. Although the lensing signals are 1 order of magnitude lower than those for clusters at z ∼ 0.2, the total signal-to-noise ratio, S/N = 13.3, is comparable, or higher, because the enormous number of background source galaxies compensates for the low lensing efficiency of the nearby cluster.

  7. Isolated galaxies

    International Nuclear Information System (INIS)

    Einasto, Maret

    1990-01-01

    To test for the possible presence of really isolated galaxies, which form a randomly distributed population in voids, we compare the distribution of most isolated galaxies in an observed sample with distributions of the same number of random points using the nearest neighbour test. The results show that the random population of really isolated galaxies does not exist - even the most isolated galaxies are connected with systems of galaxies, forming their outlying parts. (author)

  8. Visibility of galaxies

    International Nuclear Information System (INIS)

    Disney, M.J.

    1976-01-01

    It is stated that counts of galaxies could be seriously biased by selection effects, largely influenced by the brightness of the night sky. To illustrate this suppose the Earth were situated near the center of a giant elliptical galaxy. The mean surface brightness of the sky would then appear some 8 to 9 mag. brighter than is observed from our position in the Galaxy. Extragalactic space would then appear to be empty void; spiral and irregular galaxies would be invisible, and all that could be easily detected would be the core regions of galaxy ellipticals very similar to our own. Much of the Universe would be blinded by the surface brightness of the parent galaxy. This blinding, however, is a relative matter and the question arises as to what extent we are blinded by the spiral galaxy in which we exist. Strong indirect evidence exists that our knowledge of galaxies is heavily biased by the sky background, and the true population of extragalactic space may be very different from that seen. Other relevant work is also discussed, and further investigational work is indicated. (U.K.)

  9. Learning unit: Thin lenses

    Science.gov (United States)

    Nita, L.-S.

    2012-04-01

    Learning unit: Thin lenses "Why objects seen through lenses are sometimes upright and sometimes reversed" Nita Laura Simona National College of Arts and Crafts "Constantin Brancusi", Craiova, Romania 1. GEOMETRIC OPTICS. 13 hours Introduction (models, axioms, principles, conventions) 1. Thin lenses (Types of lenses. Defining elements. Path of light rays through lenses. Image formation. Required physical quantities. Lens formulas). 2. Lens systems (Non-collated lenses. Focalless systems). 3. Human eye (Functioning as an optical system. Sight defects and their corrections). 4. Optical instruments (Characteristics exemplified by a magnifying glass. Paths of light rays through a simplified photo camera. Path of light rays through a classical microscope) (Physics curriculum for the IXth grade/ 2011). This scenario exposes a learning unit based on experimental sequences (defining specific competencies), as a succession of lessons started by noticing a problem whose solution assumes the setup of an experiment under laboratory conditions. Progressive learning of theme objectives are realised with sequential experimental steps. The central cognitive process is the induction or the generalization (development of new knowledge based on observation of examples or counterexamples of the concept to be learnt). Pupil interest in theme objectives is triggered by problem-situations, for example: "In order to better see small objects I need a magnifying glass. But when using a magnifier, small object images are sometimes seen upright and sometimes seen reversed!" Along the way, pupils' reasoning will converge to the idea: "The image of an object through a lens depends on the relative distances among object, lens, and observer". Associated learning model: EXPERIMENT Specific competencies: derived from the experiment model, in agreement with the following learning unit steps I. Evoking - Anticipation: Size of the problem, formulation of hypotheses and planning of experiment. II

  10. Spectroscopic Observations of the Outflowing Wind in the Lensed Quasar SDSS J1001+5027

    Science.gov (United States)

    Misawa, Toru; Inada, Naohisa; Oguri, Masamune; Charlton, Jane C.; Eracleous, Michael; Koyamada, Suzuka; Itoh, Daisuke

    2018-02-01

    We performed spectroscopic observations of the small-separation lensed quasar SDSS J1001+5027, whose images have an angular separation θ =2\\buildrel{\\prime\\prime}\\over{.} 86, and placed constraints on the physical properties of gas clouds in the vicinity of the quasar (i.e., in the outflowing wind launched from the accretion disk). The two cylinders of sight to the two lensed images go through the same region of the outflowing wind and they become fully separated with no overlap at a very large distance from the source (∼330 pc). We discovered a clear difference in the profile of the C IV broad absorption line (BAL) detected in the two lensed images in two observing epochs. Because the kinematic components in the BAL profile do not vary in concert, the observed variations cannot be reproduced by a simple change of ionization state. If the variability is due to gas motion around the background source (i.e., the continuum source), the corresponding rotational velocity is {v}rot} ≥ 18,000 km s‑1, and their distance from the source is r≤slant 0.06 pc assuming Keplerian motion. Among three Mg II and three C IV NAL systems that we detected in the spectra, only the Mg II system at {z}abs} = 0.8716 shows a hint of variability in its Mg I profile on a rest-frame timescale of {{Δ }}{t}rest} ≤slant 191 days and an obvious velocity shear between the sightlines whose physical separation is ∼7 kpc. We interpret this as the result of motion of a cosmologically intervening absorber, perhaps located in a foreground galaxy. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

  11. 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.

  12. Galaxy mergers

    International Nuclear Information System (INIS)

    Roos, N.

    1981-01-01

    This thesis contains a series of four papers dealing with the effects of interactions among galaxies during the epoch of cluster formation. Galaxy interactions are investigated and the results incorporated in numerical simulations of the formation of groups and clusters of galaxies. The role of galaxy interactions is analysed in the more general context of simulations of an expanding universe. The evolution of galaxies in rich clusters is discussed. The results of the investigations are presented and their relation to other work done in the field are briefly reviewed and an attempt is made to link galaxy mergers to the occurrence of activity in galactic nuclei. (Auth.)

  13. An Empirical Determination of the Intergalactic Background Light Using Near-Infrared Deep Galaxy Survey Data Out to 5 Micrometers and the Gamma-Ray Opacity of the Universe

    Science.gov (United States)

    Scully, Sean T.; Malkan, Matthew A.; Stecker, Floyd W.

    2014-01-01

    We extend our previous model-independent determination of the intergalactic background light, based purely on galaxy survey data, out to a wavelength of 5 micrometers. Our approach enables us to constrain the range of photon densities, based on the uncertainties from observationally determined luminosity densities and colors. We further determine a 68% confidence upper and lower limit on the opacity of the universe to gamma-rays up to energies of 1.6/(1 + z) terraelectron volts. A comparison of our lower limit redshift-dependent opacity curves to the opacity limits derived from the results of both ground-based air Cerenkov telescope and Fermi-LAT observations of PKS 1424+240 allows us to place a new upper limit on the redshift of this source, independent of IBL modeling.

  14. Lensing and dynamics in two simple steps

    Science.gov (United States)

    Agnello, A.; Auger, M. W.; Evans, N. W.

    2013-02-01

    We present a ready-to-use method to constrain the density distribution in spherically symmetric early-type galaxy lenses. Assuming a power-law density profile, then joint use of the virial theorem and the lens equation yields simple formulae for the power-law index (or logarithmic density gradient). Any dependence on orbital anisotropy can be tightly constrained or even erased completely. Our results rely just on surface brightnesses and line-of-sight kinematics, making deprojection unnecessary. We revisit three systems that have already been examined in the literature (the Cosmic Horseshoe, the Jackpot and B1608+656) and provide our estimates. Finally, we show that the method yields a good approximation for the density profile even when the true profile is a broken power law, albeit with a mild bias towards isothermality.

  15. Search for [C II] emission in z = 6.5-11 star-forming galaxies

    International Nuclear Information System (INIS)

    González-López, Jorge; Infante, Leopoldo; Riechers, Dominik A.

    2014-01-01

    We present the search for the [C II] emission line in three z > 6.5 Lyα emitters (LAEs) and one J-dropout galaxy using the Combined Array for Research in Millimeter-wave Astronomy and the Plateau de Bure Interferometer. We observed three bright z ∼ 6.5-7 LAEs discovered in the Subaru Deep Field (SDF) and the multiple imaged lensed z ∼ 11 galaxy candidate found behind the galaxy cluster MACSJ0647.7+7015. For the LAEs IOK-1 (z = 6.965), SDF J132415.7+273058 (z = 6.541), and SDF J132408.3+271543 (z = 6.554) we find upper limits for the [C II] line luminosity of <2.05, <4.52, and <10.56 × 10 8 L ☉ , respectively. We find upper limits to the far-IR (FIR) luminosity of the galaxies using a spectral energy distribution template of the local galaxy NGC 6946 and taking into account the effects of the cosmic microwave background on the millimeter observations. For IOK-1, SDF J132415.7+273058, and SDF J132408.3+271543 we find upper limits for the FIR luminosity of <2.33, 3.79, and 7.72 × 10 11 L ☉ , respectively. For the lensed galaxy MACS0647-JD, one of the highest-redshift galaxy candidates to date with z ph =10.7 −0.4 +0.6 , we put an upper limit in the [C II] emission of <1.36 × 10 8 × (μ/15) –1 L ☉ and an upper limit in the FIR luminosity of <6.1 × 10 10 × (μ/15) –1 L ☉ (where μ is the magnification factor). We explore the different conditions relevant for the search for [C II] emission in high-redshift galaxies as well as the difficulties for future observations with the Atacama Large Millimeter/submillimeter Array (ALMA) and the Cerro Chajnantor Atacama Telescope (CCAT).

  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. Searching for supernovae in the multiply-imaged galaxies behind the gravitational telescope A370

    OpenAIRE

    Petrushevska, T.; Goobar, A.; Lagattuta, D. J.; Amanullah, R.; Hangard, L.; Fabbro, S.; Lidman, C.; Paech, K.; Richard, J.; Kneib, J. P.

    2018-01-01

    Strong lensing by massive galaxy clusters can provide magnification of the flux and even multiple images of the galaxies that lie behind them. This phenomenon facilitates observations of high-redshift supernovae (SNe), that would otherwise remain undetected. Type Ia supernovae (SNe Ia) detections are of particular interest because of their standard brightness, since they can be used to improve either cluster lensing models or cosmological parameter measurements. We present a ground-based, nea...

  19. Active Galaxies

    DEFF Research Database (Denmark)

    Kilerci Eser, Ece

    Galaxy formation and evolution is one of the main research themes of modern astronomy. Active galaxies such as Active Galactic Nuclei (AGN) and Ultraluminous Infrared Galaxies (ULIRGs) are important evolutionary stages of galaxies. The ULIRG stage is mostly associated with galaxy mergers...... and interactions. During the interactions of gas-rich galaxies, the gas inflows towards the centers of the galaxies and can trigger both star formation and AGN activity. The ULIRG stage includes rapid star formation activity and fast black hole growth that is enshrouded by dust. Once the AGN emission...... one is related to the mass estimates of supermassive black holes (SMBHs). Mass estimates of SMBHs are important to understand the formation and evolution of SMBHs and their host galaxies. Black hole masses in Type 1 AGN are measured with the reverberation mapping (RM) technique. Reverberation mapping...

  20. Galaxy Formation

    DEFF Research Database (Denmark)

    Sparre, Martin

    Galaxy formation is an enormously complex discipline due to the many physical processes that play a role in shaping galaxies. The objective of this thesis is to study galaxy formation with two different approaches: First, numerical simulations are used to study the structure of dark matter and how...... galaxies form stars throughout the history of the Universe, and secondly it is shown that observations of gamma-ray bursts (GRBs) can be used to probe galaxies with active star formation in the early Universe. A conclusion from the hydrodynamical simulations is that the galaxies from the stateof...... is important, since it helps constraining chemical evolution models at high redshift. A new project studying how the population of galaxies hosting GRBs relate to other galaxy population is outlined in the conclusion of this thesis. The core of this project will be to quantify how the stellar mass function...

  1. Technology Development for Cosmic Microwave Background Cosmology

    Science.gov (United States)

    Munson, Charles D.

    2017-05-01

    The Cosmic Microwave Background (CMB) offers a unique window into the early universe by probing thermal radiation remaining from the big bang. Due to its low temperature and bright foregrounds, its thorough characterization requires technological advancement beyond the current state-of-the-art. In this thesis, I present the development and fabrication of novel metamaterial silicon optics to improve the sensitivity of current and future CMB telescopes. By machining subwavelength features into the silicon surfaces, traditional antireflection coatings can be replaced by all-silicon metamaterials that significantly reduce reflections over previous approaches. I discuss the design of these structured surfaces and the design and construction of a sophisticated fabrication facility necessary to implement this technology on large diameter (30+ cm) lenses for the Atacama Cosmology Telescope Polarization project (ACTPol). I then apply this metamaterial technology to the development of improved free-space filters for millimeter and sub-millimeter wavelength imaging (focusing specifically on blocking infrared radiation, necessary for current cryogenic detector systems). This produces a highly effective infrared-blocking filter, blocking over 99% of the incident power from a 300 K blackbody while maintaining transmission of better than 99% in a target CMB observing band (between 70 and 170 GHz). I conclude with a discussion of the development of a real-space simulation framework to assist in better understanding current CMB results and forecasting for future experiments. By taking a CMB realization and adding to it accurate real-space modeling of the Sunyaev-Zel'dovich effect and weak lensing distortions (introduced by galaxy clusters), a better understanding of the impacts of large scale structure on the CMB can be obtained.

  2. 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.

  3. The JVAS/CLASS search for 6-arcsec to 15-arcsec image separation lensing

    NARCIS (Netherlands)

    Phillips, PM; Browne, IWA; Jackson, NJ; Wilkinson, PN; Mao, S; Rusin, D; Marlow, DR; Snellen, [No Value; Neeser, M

    2001-01-01

    The Jodrell Bank-VLA Astrometric Survey (JVAS) and the Cosmic Lens All Sky Survey (CLASS) have been systematically searched for multiple gravitational imaging of sources with image separations between 6 arcsec and 15 arcsec, associated with galaxy group and cluster lensing masses. The radio and

  4. Mask effects on cosmological studies with weak-lensing peak statistics

    International Nuclear Information System (INIS)

    Liu, Xiangkun; Pan, Chuzhong; Fan, Zuhui; Wang, Qiao

    2014-01-01

    With numerical simulations, we analyze in detail how the bad data removal, i.e., the mask effect, can influence the peak statistics of the weak-lensing convergence field reconstructed from the shear measurement of background galaxies. It is found that high peak fractions are systematically enhanced because of the presence of masks; the larger the masked area is, the higher the enhancement is. In the case where the total masked area is about 13% of the survey area, the fraction of peaks with signal-to-noise ratio ν ≥ 3 is ∼11% of the total number of peaks, compared with ∼7% of the mask-free case in our considered cosmological model. This can have significant effects on cosmological studies with weak-lensing convergence peak statistics, inducing a large bias in the parameter constraints if the effects are not taken into account properly. Even for a survey area of 9 deg 2 , the bias in (Ω m , σ 8 ) is already intolerably large and close to 3σ. It is noted that most of the affected peaks are close to the masked regions. Therefore, excluding peaks in those regions in the peak statistics can reduce the bias effect but at the expense of losing usable survey areas. Further investigations find that the enhancement of the number of high peaks around the masked regions can be largely attributed to the smaller number of galaxies usable in the weak-lensing convergence reconstruction, leading to higher noise than that of the areas away from the masks. We thus develop a model in which we exclude only those very large masks with radius larger than 3' but keep all the other masked regions in peak counting statistics. For the remaining part, we treat the areas close to and away from the masked regions separately with different noise levels. It is shown that this two-noise-level model can account for the mask effect on peak statistics very well, and the bias in cosmological parameters is significantly reduced if this model is applied in the parameter fitting.

  5. Giant luminous arcs from lensing: determination of the mass distribution inside distant cluster cores

    International Nuclear Information System (INIS)

    Hammer, F.; Rigaut, F.

    1989-01-01

    The observations of giant luminous arcs are used in the context of the gravitational lensing theory, to investigate the distribution of the deflecting matter, usually situated in the cores of distant clusters. Analytic equations of the caustic curves are presented for a multi-point mass model, which roughly accounts for the observed arc properties. A more general lensing model is introduced, where the lensing objects (galaxies, groups and clusters of galaxies) are extended and follow the r 1/4 law. Numerical simulations reproduce pixel by pixel all the gravitational images, including the arcs, found in the cores of the A 370 and CI2244-02 clusters. They are consistent with the use of the observations of luminous matter and X-ray emitting matter as a tracer of the total mass distribution

  6. Giant luminous arcs from lensing: determination of the mass distribution inside distant cluster cores

    Energy Technology Data Exchange (ETDEWEB)

    Hammer, F.; Rigaut, F. (Observatoire de Paris, Section de Meudon, 92 (FR))

    1989-12-01

    The observations of giant luminous arcs are used in the context of the gravitational lensing theory, to investigate the distribution of the deflecting matter, usually situated in the cores of distant clusters. Analytic equations of the caustic curves are presented for a multi-point mass model, which roughly accounts for the observed arc properties. A more general lensing model is introduced, where the lensing objects (galaxies, groups and clusters of galaxies) are extended and follow the r{sup 1/4} law. Numerical simulations reproduce pixel by pixel all the gravitational images, including the arcs, found in the cores of the A 370 and CI2244-02 clusters. They are consistent with the use of the observations of luminous matter and X-ray emitting matter as a tracer of the total mass distribution.

  7. Cosmological measurements with general relativistic galaxy correlations

    Energy Technology Data Exchange (ETDEWEB)

    Raccanelli, Alvise [Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218 (United States); Montanari, Francesco; Durrer, Ruth [Département de Physique Théorique, Université de Genève, 24 quai Ernest Ansermet, 1211 Genève 4 (Switzerland); Bertacca, Daniele [Argelander-Institut für Astronomie, Auf dem Hügel 71, D-53121 Bonn (Germany); Doré, Olivier, E-mail: alvise@jhu.edu, E-mail: francesco.montanari@helsinki.fi, E-mail: daniele.bertacca@gmail.com, E-mail: Olivier.P.Dore@jpl.nasa.gov, E-mail: ruth.durrer@unige.ch [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2016-05-01

    We investigate the cosmological dependence and the constraining power of large-scale galaxy correlations, including all redshift-distortions, wide-angle, lensing and gravitational potential effects on linear scales. We analyze the cosmological information present in the lensing convergence and in the gravitational potential terms describing the so-called ''relativistic effects'', and we find that, while smaller than the information contained in intrinsic galaxy clustering, it is not negligible. We investigate how neglecting them does bias cosmological measurements performed by future spectroscopic and photometric large-scale surveys such as SKA and Euclid. We perform a Fisher analysis using the CLASS code, modified to include scale-dependent galaxy bias and redshift-dependent magnification and evolution bias. Our results show that neglecting relativistic terms, especially lensing convergence, introduces an error in the forecasted precision in measuring cosmological parameters of the order of a few tens of percent, in particular when measuring the matter content of the Universe and primordial non-Gaussianity parameters. The analysis suggests a possible substantial systematic error in cosmological parameter constraints. Therefore, we argue that radial correlations and integrated relativistic terms need to be taken into account when forecasting the constraining power of future large-scale number counts of galaxy surveys.

  8. A Portrait of One Hundred Thousand and One Galaxies

    Science.gov (United States)

    2002-08-01

    , identified and retrieved all available broad-band and H-alpha images of NGC 300 available in the ESO Science Data Archive. Most of these have been observed for the project by Gieren and his colleagues, described above. However, the scientific interest of the German astronomers was very different from that of their colleagues and they were not at all concerned about the main object in the field, NGC 300. In a very different approach, they instead wanted to study those images to measure the amount of dark matter in the Universe, by means of the weak gravitational lensing effect produced by distant galaxy clusters. Various observations, ranging from the measurement of internal motions ("rotation curves") in spiral galaxies to the presence of hot X-ray gas in clusters of galaxies and the motion of galaxies in those clusters, indicate that there is about ten times more matter in the Universe than what is observed in the form of stars, gas and galaxies ("luminous matter"). As this additional matter does not emit light at any wavelengths, it is commonly referred to as "dark" matter - its true nature is yet entirely unclear. Insight into the distribution of dark matter in the Universe can be gained by looking at the shapes of images of very remote galaxies, billions of light-years away, cf. ESO PR 24/00. Light from such distant objects travels vast distances through space before arriving here on Earth, and whenever it passes heavy clusters of galaxies, it is bent a little due to the associated gravitational field. Thus, in long-exposure, high-quality images, this "weak lensing" effect can be perceived as a coherent pattern of distortion of the images of background galaxies. Gravitational lensing in the NGC 300 field ESO PR Photo 18d/02 ESO PR Photo 18d/02 [Preview - JPEG: 400 x 495 pix - 82k] [Full-Res - JPEG: 1304 x 1615 pix - 3.2M] Caption : PR Photo 18d/02 shows the distant cluster of galaxies CL0053-37 , as imaged on the WFI photo of the NGC 300 sky field. The elongated

  9. The mass-temperature relation for clusters of galaxies

    DEFF Research Database (Denmark)

    Hjorth, J.; Oukbir, J.; van Kampen, E.

    1998-01-01

    temperatures measured with ASCA and masses inferred from weak and strong gravitational lensing. The surface lensing masses are deprojected in accordance with N-body simulations and analytic results. The data are well-fitted by the mass-temperature relation and are consistent with the empirical normalization...... with wide-held HST imaging could provide a sensitive test of the normalization and intrinsic scatter of the relation, resulting in a powerful and expedient way of measuring masses of clusters of galaxies. In addition, as M(r)/r las derived from lensing) is dependent on the cosmological model at high...

  10. Lensing bias to CMB polarization measurements of compensated isocurvature perturbations

    Science.gov (United States)

    Heinrich, Chen

    2018-01-01

    Compensated isocurvature perturbations (CIPs) are opposite spatial fluctuations in the baryon and dark matter (DM) densities. They arise in the curvaton model and some models of baryogenesis. While the gravitational effects of baryon fluctuations are compensated by those of DM, leaving no observable impacts on the cosmic microwave background (CMB) at first order, they modulate the sound horizon at recombination, thereby correlating CMB anisotropies at different multipoles. As a result, CIPs can be reconstructed using quadratic estimators similarly to CMB detection of gravitational lensing. Because of these similarities, however, the CIP estimators are biased with lensing contributions that must be subtracted. These lensing contributions for CMB polarization measurement of CIPs are found to roughly triple the noise power of the total CIP estimator on large scales. In addition, the cross power with temperature and E -mode polarization are contaminated by lensing-ISW (integrated Sachs-Wolfe) correlations and reionization-lensing correlations respectively. For a cosmic-variance-limited temperature and polarization experiment measuring out to multipoles lmax=2500 , the lensing noise raises the detection threshold by a factor of 1.5, leaving a 2.7 σ detection possible for the maximal CIP signal in the curvaton model.

  11. 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.

  12. Planck 2013 results. XVII. Gravitational lensing by large-scale structure

    DEFF Research Database (Denmark)

    Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.

    2013-01-01

    On the arcminute angular scales probed by Planck, the cosmic microwave background (CMB) anisotropies are gently perturbed by gravitational lensing. Here we present a detailed study of this eect, detecting lensing independently in the 100, 143, and 217 GHz frequency bands with an overall significa...

  13. Galaxies and clusters of galaxies

    International Nuclear Information System (INIS)

    Salpeter, E.E.

    1982-01-01

    Stellar populations and massive halos, the properties of individual galaxies, and the clusters of galaxies are discussed. Baade's concept of the two stellar populations in our Galaxy had an important influence on the theories of stellar evolution. In Baade's day, there were two puzzling questions. Population II stars manage to form more rapidly than population I stars. Population II has lower rotational velocity than population I. This story is affected by the presence of an extended, massive halo which was not known in Baade's day. It is known from galaxy rotation curves that massive halos extend much further out. The most striking feature about the variation amongst galaxies is the separation between elliptical and spiral galaxies, with SO-galaxies occupying an intermediate position. The absolute luminosity L of a galaxy provides the second parameter in a two-dimensional classification scheme. In many ways, elliptical galaxies bear the same relationship to late-type spirals as does our stellar population II to population I. Most galaxies occur in some kind of groupings, ranging from a small group such as Local Group to a rich and dense cluster such as the Coma cluster. The formation of galaxies is connected with the formation of clusters. Various models are presented and discussed. (Kato, T.)

  14. Gas, Dust, and Quenching of Dusty Galaxies in the Early Universe

    Science.gov (United States)

    Spilker, Justin Scott

    In this dissertation, I study various aspects related to the gas and star formation in dusty star-forming galaxies in the distant universe. My dissertation is heavily based on observations made by the Atacama Large Millimeter/submillimeter Array (ALMA), observing a sample of gravitationally lensed high-redshift dusty galaxies originally discovered by the South Pole Telescope (SPT). In addition to the introductions to the individual chapters, Chapter 1 provides a broader background to the study of these objects and places them in the overall context of galaxy evolution. In Chapter 2 I describe a technique designed to search for faint molecular lines in the spectrum of high-redshift dusty galaxies. The brightest molecular lines in the spectra of these objects are due to carbon monoxide, but a host of other species are present in the interstellar media. These other molecules trace gas of a wide range of temperatures and densities, but are generally ten times fainter than the brighter CO lines. I detected several other molecular lines, and used them to characterize the conditions of the interstellar gas. This work was published in Spilker et al. (2014). In Chapter 3, I describe a technique for modeling the effects of gravitational lensing which is optimized for data from interferometers such as ALMA. Using these models and data for a large sample of objects from ALMA, I studied the intrinsic properties of the sample such as the source sizes and luminosities. I used these intrinsic properties to revisit topics from the literature which benefit from the additional size information I determined. This work was published in Spilker et al. (2016). In Chapter 4, I use the modeling technique I developed to investigate the relationship between the star formation and the cold molecular gas from which stars form in two objects selected from the SPT sample. Using the models of the source, I was able to determine the mass of molecular gas in these objects using several independent

  15. Comparative Evaluation of Ultraviolet and Visible Light Transmittance through Prescriptive Ophthalmic Minus Lenses

    Directory of Open Access Journals (Sweden)

    Mohammadreza Nazari

    2014-06-01

    Full Text Available Background: Wearing spectacles is the most common approach in correcting the refractive errors worldwide. Due to harmful effects of overexposure to solar ultraviolet radiations, the usage of multi-layer coatings in ophthalmic lenses has recently been increased. These lenses can reduce the reflections and hence increase the transmission of visible light; they can also decrease the transmission of ultraviolet rays. This study aims to compare the transmission of ultraviolet (A and B and visible rays through coated and uncoated prescriptive ophthalmic plastic lenses.Materials and Methods: In this study, 39 minus non-photochromic multi-coated white plastic single-vision lenses; 9 similar lenses but without any coatings were assessed by spectral transmittancemeter for evaluation of the transmission of visible and ultraviolet rays.Results: The transmission of visible light was 97.9%±1.07% for coated lenses and 93.5%±0.54% for lenses without coating. Ultraviolet-A transmission was 12.15%±8.02% for coated lenses compared to 66.27%±23.92% in lenses without coating. The transmission of ultraviolet-B rays was 1.21%±0.4% and 23.0%±15.97% for lenses with and without coatings, respectively.Conclusion: The transmission of visible light was significantly higher in multi-coated lenses compared to uncoated samples; whereas the transmissions of ultraviolet rays in multi-coated lenses were significantly lower than uncoated ones. Therefore, it is recommended that, except for particular cases, prescribed lenses be equipped with this multi-layer coating.

  16. The DES Science Verification Weak Lensing Shear Catalogs

    International Nuclear Information System (INIS)

    Jarvis, M.

    2016-01-01

    We present weak lensing shear catalogs for 139 square degrees of data taken during the Science Verification (SV) time for the new Dark Energy Camera (DECam) being used for the Dark Energy Survey (DES). We describe our object selection, point spread function estimation and shear measurement procedures using two independent shear pipelines, IM3SHAPE and NGMIX, which produce catalogs of 2.12 million and 3.44 million galaxies respectively. We also detail a set of null tests for the shear measurements and find that they pass the requirements for systematic errors at the level necessary for weak lensing science applications using the SV data. Furthermore, we discuss some of the planned algorithmic improvements that will be necessary to produce sufficiently accurate shear catalogs for the full 5-year DES, which is expected to cover 5000 square degrees

  17. Weak gravitational lensing towards high-precision cosmology

    International Nuclear Information System (INIS)

    Berge, Joel

    2007-01-01

    This thesis aims at studying weak gravitational lensing as a tool for high-precision cosmology. We first present the development and validation of a precise and accurate tool for measuring gravitational shear, based on the shapelets formalism. We then use shapelets on real images for the first time, we analyze CFHTLS images, and combine them with XMM-LSS data. We measure the normalisation of the density fluctuations power spectrum σ 8 , and the one of the mass-temperature relation for galaxy clusters. The analysis of the Hubble space telescope COSMOS field confirms our σ 8 measurement and introduces tomography. Finally, aiming at optimizing future surveys, we compare the individual and combined merits of cluster counts and power spectrum tomography. Our results demonstrate that next generation surveys will allow weak lensing to yield its full potential in the high-precision cosmology era. (author) [fr

  18. Finding strong gravitational lenses in the Kilo Degree Survey with Convolutional Neural Networks

    Science.gov (United States)

    Petrillo, C. E.; Tortora, C.; Chatterjee, S.; Vernardos, G.; Koopmans, L. V. E.; Verdoes Kleijn, G.; Napolitano, N. R.; Covone, G.; Schneider, P.; Grado, A.; McFarland, J.

    2017-11-01

    The volume of data that will be produced by new-generation surveys requires automatic classification methods to select and analyse sources. Indeed, this is the case for the search for strong gravitational lenses, where the population of the detectable lensed sources is only a very small fraction of the full source population. We apply for the first time a morphological classification method based on a Convolutional Neural Network (CNN) for recognizing strong gravitational lenses in 255 deg2 of the Kilo Degree Survey (KiDS), one of the current-generation optical wide surveys. The CNN is currently optimized to recognize lenses with Einstein radii ≳1.4 arcsec, about twice the r-band seeing in KiDS. In a sample of 21 789 colour-magnitude selected luminous red galaxies (LRGs), of which three are known lenses, the CNN retrieves 761 strong-lens candidates and correctly classifies two out of three of the known lenses. The misclassified lens has an Einstein radius below the range on which the algorithm is trained. We down-select the most reliable 56 candidates by a joint visual inspection. This final sample is presented and discussed. A conservative estimate based on our results shows that with our proposed method it should be possible to find ∼100 massive LRG-galaxy lenses at z ≲ 0.4 in KiDS when completed. In the most optimistic scenario, this number can grow considerably (to maximally ∼2400 lenses), when widening the colour-magnitude selection and training the CNN to recognize smaller image-separation lens systems.

  19. Evolution of galaxies

    International Nuclear Information System (INIS)

    Palous, J.

    1987-01-01

    The proceedings contain 87 papers divided into 8 chapters. The chapter Bipolar outflows and star formations contains papers on optical and infrared observations of young bipolar outflow objects and the theory thereof, and on observations of cometary nebulae. The chapter Masers and early stellar evolution discusses molecular masers and star forming regions. The following chapter contains papers on initial mass function and star formation rates in galaxies. The chapter Clusters and star formation contains data on OB associations and open star clusters, their development and observations, CO and H 2 in our galaxy, the four vector model of radio emission and an atlas of the wavelength dependence of ultraviolet extinction in the Galaxy. The most voluminous is the chapter Evolution of galaxies. It contains papers on the theories of the physical and chemodynamic development of galaxies of different types, rotation research and rotation velocities of galaxies and their arms, and on mathematical and laboratory models of morphological development. Chapter seven contains papers dealing with active extragalactic objects, quasars and active galactic nuclei. The last chapter discusses cosmological models, the theory of the inflationary universe, and presents an interpretation of the central void and X-ray background. (M.D.). 299 figs., 48 tabs., 1651 refs

  20. Noise Estimates for Measurements of Weak Lensing from the Lyman-alpha Forest

    Science.gov (United States)

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

    2018-03-01

    Lensing changes the apparent separation between pixels in the Lyman-α forest of separate quasars or high redshift objects by changing their observed positions on the sky. This changes the implied correlations in the absorption and in particular makes the Lyman-α forest correlation function, or power spectrum, locally anisotropic in the plane of the sky. We have proposed a method for measuring weak lensing using this effect. Here we estimate the noise expected in weak lensing maps and power spectra for different sets of observational parameters. We find that surveys of the size and quality of the ones being done today and ones planned for the future will be able to measure the lensing power spectrum at a source redshift of z ≃ 2.5 with high precision and even be able to image the distribution of foreground matter with high fidelity on degree scales. For example, we predict that Lyman-α forest lensing measurements from the DESI and WEAVE surveys should yield the mass fluctuation amplitude with a statistical error of ˜3%, eBOSS ˜6%. and the proposed MSE survey less than 1%. By dividing the redshift range into multiple bins some tomographic lensing information should be accessible as well. This would allow for cosmological lensing measurements at higher redshift than are accessible with galaxy shear surveys and correspondingly better constraints on the evolution of dark energy at relatively early times.

  1. THE SLACS SURVEY. VIII. THE RELATION BETWEEN ENVIRONMENT AND INTERNAL STRUCTURE OF EARLY-TYPE GALAXIES

    NARCIS (Netherlands)

    Treu, Tommaso; Gavazzi, Raphael; Gorecki, Alexia; Marshall, Philip J.; Koopmans, Leon V. E.; Bolton, Adam S.; Moustakas, Leonidas A.; Burles, Scott

    2009-01-01

    We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the SLACS Survey. The Sloan Digital Sky Survey (SDSS) database is used to determine two measures of overdensity of galaxies around each lens-the projected

  2. A clumpy and anisotropic galaxy halo at redshift 1 from gravitational-arc tomography.

    Science.gov (United States)

    Lopez, Sebastian; Tejos, Nicolas; Ledoux, Cédric; Barrientos, L Felipe; Sharon, Keren; Rigby, Jane R; Gladders, Michael D; Bayliss, Matthew B; Pessa, Ismael

    2018-02-22

    Every star-forming galaxy has a halo of metal-enriched gas that extends out to at least 100 kiloparsecs, as revealed by the absorption lines that this gas imprints on the spectra of background quasars. However, quasars are sparse and typically probe only one narrow beam of emission through the intervening galaxy. Close quasar pairs and gravitationally lensed quasars have been used to circumvent this inherently one-dimensional technique, but these objects are rare and the structure of the circumgalactic medium remains poorly constrained. As a result, our understanding of the physical processes that drive the recycling of baryons across the lifetime of a galaxy is limited. Here we report integral-field (tomographic) spectroscopy of an extended background source-a bright, giant gravitational arc. We can thus coherently map the spatial and kinematic distribution of Mg ɪɪ absorption-a standard tracer of enriched gas-in an intervening galaxy system at redshift 0.98 (around 8 billion years ago). Our gravitational-arc tomography unveils a clumpy medium in which the absorption strength decreases with increasing distance from the galaxy system, in good agreement with results for quasars. Furthermore, we find strong evidence that the gas is not distributed isotropically. Interestingly, we detect little kinematic variation over a projected area of approximately 600 square kiloparsecs, with all line-of-sight velocities confined to within a few tens of kilometres per second of each other. These results suggest that the detected absorption originates from entrained recycled material, rather than in a galactic outflow.

  3. A clumpy and anisotropic galaxy halo at redshift 1 from gravitational-arc tomography

    Science.gov (United States)

    Lopez, Sebastian; Tejos, Nicolas; Ledoux, Cédric; Barrientos, L. Felipe; Sharon, Keren; Rigby, Jane R.; Gladders, Michael D.; Bayliss, Matthew B.; Pessa, Ismael

    2018-02-01

    Every star-forming galaxy has a halo of metal-enriched gas that extends out to at least 100 kiloparsecs, as revealed by the absorption lines that this gas imprints on the spectra of background quasars. However, quasars are sparse and typically probe only one narrow beam of emission through the intervening galaxy. Close quasar pairs and gravitationally lensed quasars have been used to circumvent this inherently one-dimensional technique, but these objects are rare and the structure of the circumgalactic medium remains poorly constrained. As a result, our understanding of the physical processes that drive the recycling of baryons across the lifetime of a galaxy is limited. Here we report integral-field (tomographic) spectroscopy of an extended background source—a bright, giant gravitational arc. We can thus coherently map the spatial and kinematic distribution of Mg ɪɪ absorption—a standard tracer of enriched gas—in an intervening galaxy system at redshift 0.98 (around 8 billion years ago). Our gravitational-arc tomography unveils a clumpy medium in which the absorption strength decreases with increasing distance from the galaxy system, in good agreement with results for quasars. Furthermore, we find strong evidence that the gas is not distributed isotropically. Interestingly, we detect little kinematic variation over a projected area of approximately 600 square kiloparsecs, with all line-of-sight velocities confined to within a few tens of kilometres per second of each other. These results suggest that the detected absorption originates from entrained recycled material, rather than in a galactic outflow.

  4. Do satellite galaxies trace matter in galaxy clusters?

    Science.gov (United States)

    Wang, Chunxiang; Li, Ran; Gao, Liang; Shan, Huanyuan; Kneib, Jean-Paul; Wang, Wenting; Chen, Gang; Makler, Martin; Pereira, Maria E. S.; Wang, Lin; Maia, Marcio A. G.; Erben, Thomas

    2018-04-01

    The spatial distribution of satellite galaxies encodes rich information of the structure and assembly history of galaxy clusters. In this paper, we select a red-sequence Matched-filter Probabilistic Percolation cluster sample in SDSS Stripe 82 region with 0.1 ≤ z ≤ 0.33, 20 0.7. Using the high-quality weak lensing data from CS82 Survey, we constrain the mass profile of this sample. Then we compare directly the mass density profile with the satellite number density profile. We find that the total mass and number density profiles have the same shape, both well fitted by an NFW profile. The scale radii agree with each other within a 1σ error (r_s,gal=0.34_{-0.03}^{+0.04} Mpc versus r_s=0.37_{-0.10}^{+0.15} Mpc).

  5. Matching Supernovae to Galaxies

    Science.gov (United States)

    Kohler, Susanna

    2016-12-01

    One of the major challenges for modern supernova surveys is identifying the galaxy that hosted each explosion. Is there an accurate and efficient way to do this that avoids investing significant human resources?Why Identify Hosts?One problem in host galaxy identification. Here, the supernova lies between two galaxies but though the centroid of the galaxy on the right is closer in angular separation, this may be a distant background galaxy that is not actually near the supernova. [Gupta et al. 2016]Supernovae are a critical tool for making cosmological predictions that help us to understand our universe. But supernova cosmology relies on accurately identifying the properties of the supernovae including their redshifts. Since spectroscopic followup of supernova detections often isnt possible, we rely on observations of the supernova host galaxies to obtain redshifts.But how do we identify which galaxy hosted a supernova? This seems like a simple problem, but there are many complicating factors a seemingly nearby galaxy could be a distant background galaxy, for instance, or a supernovas host could be too faint to spot.The authors algorithm takes into account confusion, a measure of how likely the supernova is to be mismatched. In these illustrations of low (left) and high (right) confusion, the supernova is represented by a blue star, and the green circles represent possible host galaxies. [Gupta et al. 2016]Turning to AutomationBefore the era of large supernovae surveys, searching for host galaxies was done primarily by visual inspection. But current projects like the Dark Energy Surveys Supernova Program is finding supernovae by the thousands, and the upcoming Large Synoptic Survey Telescope will likely discover hundreds of thousands. Visual inspection will not be possible in the face of this volume of data so an accurate and efficient automated method is clearly needed!To this end, a team of scientists led by Ravi Gupta (Argonne National Laboratory) has recently

  6. The Morphologies and Alignments of Gas, Mass, and the Central Galaxies of CLASH Clusters of Galaxies

    Science.gov (United States)

    Donahue, Megan; Ettori, Stefano; Rasia, Elena; Sayers, Jack; Zitrin, Adi; Meneghetti, Massimo; Voit, G. Mark; Golwala, Sunil; Czakon, Nicole; Yepes, Gustavo; Baldi, Alessandro; Koekemoer, Anton; Postman, Marc

    2016-03-01

    Morphology is often used to infer the state of relaxation of galaxy clusters. The regularity, symmetry, and degree to which a cluster is centrally concentrated inform quantitative measures of cluster morphology. The Cluster Lensing and Supernova survey with Hubble Space Telescope (CLASH) used weak and strong lensing to measure the distribution of matter within a sample of 25 clusters, 20 of which were deemed to be “relaxed” based on their X-ray morphology and alignment of the X-ray emission with the Brightest Cluster Galaxy. Toward a quantitative characterization of this important sample of clusters, we present uniformly estimated X-ray morphological statistics for all 25 CLASH clusters. We compare X-ray morphologies of CLASH clusters with those identically measured for a large sample of simulated clusters from the MUSIC-2 simulations, selected by mass. We confirm a threshold in X-ray surface brightness concentration of C ≳ 0.4 for cool-core clusters, where C is the ratio of X-ray emission inside 100 h70-1 kpc compared to inside 500 {h}70-1 kpc. We report and compare morphologies of these clusters inferred from Sunyaev-Zeldovich Effect (SZE) maps of the hot gas and in from projected mass maps based on strong and weak lensing. We find a strong agreement in alignments of the orientation of major axes for the lensing, X-ray, and SZE maps of nearly all of the CLASH clusters at radii of 500 kpc (approximately 1/2 R500 for these clusters). We also find a striking alignment of clusters shapes at the 500 kpc scale, as measured with X-ray, SZE, and lensing, with that of the near-infrared stellar light at 10 kpc scales for the 20 “relaxed” clusters. This strong alignment indicates a powerful coupling between the cluster- and galaxy-scale galaxy formation processes.

  7. 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

  8. Cosmological tests with strong gravitational lenses using Gaussian processes

    Science.gov (United States)

    Yennapureddy, Manoj K.; Melia, Fulvio

    2018-03-01

    Strong gravitational lenses provide source/lens distance ratios D_{obs} useful in cosmological tests. Previously, a catalog of 69 such systems was used in a one-on-one comparison between the standard model, Λ CDM, and the Rh=ct universe, which has thus far been favored by the application of model selection tools to many other kinds of data. But in that work, the use of model parametric fits to the observations could not easily distinguish between these two cosmologies, in part due to the limited measurement precision. Here, we instead use recently developed methods based on Gaussian Processes (GP), in which D_{obs} may be reconstructed directly from the data without assuming any parametric form. This approach not only smooths out the reconstructed function representing the data, but also reduces the size of the 1σ confidence regions, thereby providing greater power to discern between different models. With the current sample size, we show that analyzing strong lenses with a GP approach can definitely improve the model comparisons, producing probability differences in the range ˜ 10-30%. These results are still marginal, however, given the relatively small sample. Nonetheless, we conclude that the probability of Rh=ct being the correct cosmology is somewhat higher than that of Λ CDM, with a degree of significance that grows with the number of sources in the subsamples we consider. Future surveys will significantly grow the catalog of strong lenses and will therefore benefit considerably from the GP method we describe here. In addition, we point out that if the Rh=ct universe is eventually shown to be the correct cosmology, the lack of free parameters in the study of strong lenses should provide a remarkably powerful tool for uncovering the mass structure in lensing galaxies.

  9. Gravitational lensing of gravitational waves: A statistical perspective

    Science.gov (United States)

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

    2018-02-01

    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 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 percent for the aLIGO survey and ˜6 percent 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%) will have time delays less than ˜1 month which will be far shorter than survey durations.

  10. 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.

  11. Stacked Weak Lensing Mass Calibration: Estimators, Systematics, and Impact on Cosmological Parameter Constraints

    Energy Technology Data Exchange (ETDEWEB)

    Rozo, Eduardo; /U. Chicago /Chicago U., KICP; Wu, Hao-Yi; /KIPAC, Menlo Park; Schmidt, Fabian; /Caltech

    2011-11-04

    When extracting the weak lensing shear signal, one may employ either locally normalized or globally normalized shear estimators. The former is the standard approach when estimating cluster masses, while the latter is the more common method among peak finding efforts. While both approaches have identical signal-to-noise in the weak lensing limit, it is possible that higher order corrections or systematic considerations make one estimator preferable over the other. In this paper, we consider the efficacy of both estimators within the context of stacked weak lensing mass estimation in the Dark Energy Survey (DES). We find that the two estimators have nearly identical statistical precision, even after including higher order corrections, but that these corrections must be incorporated into the analysis to avoid observationally relevant biases in the recovered masses. We also demonstrate that finite bin-width effects may be significant if not properly accounted for, and that the two estimators exhibit different systematics, particularly with respect to contamination of the source catalog by foreground galaxies. Thus, the two estimators may be employed as a systematic cross-check of each other. Stacked weak lensing in the DES should allow for the mean mass of galaxy clusters to be calibrated to {approx}2% precision (statistical only), which can improve the figure of merit of the DES cluster abundance experiment by a factor of {approx}3 relative to the self-calibration expectation. A companion paper investigates how the two types of estimators considered here impact weak lensing peak finding efforts.

  12. Galaxy Disks

    NARCIS (Netherlands)

    van der Kruit, P. C.; Freeman, K. C.

    The disks of disk galaxies contain a substantial fraction of their baryonic matter and angular momentum, and much of the evolutionary activity in these galaxies, such as the formation of stars, spiral arms, bars and rings, and the various forms of secular evolution, takes place in their disks. The

  13. A massive, dead disk galaxy in the early Universe.

    Science.gov (United States)

    Toft, Sune; Zabl, Johannes; Richard, Johan; Gallazzi, Anna; Zibetti, Stefano; Prescott, Moire; Grillo, Claudio; Man, Allison W S; Lee, Nicholas Y; Gómez-Guijarro, Carlos; Stockmann, Mikkel; Magdis, Georgios; Steinhardt, Charles L

    2017-06-21

    At redshift z = 2, when the Universe was just three billion years old, half of the most massive galaxies were extremely compact and had already exhausted their fuel for star formation. It is believed that they were formed in intense nuclear starbursts and that they ultimately grew into the most massive local elliptical galaxies seen today, through mergers with minor companions, but validating this picture requires higher-resolution observations of their centres than is currently possible. Magnification from gravitational lensing offers an opportunity to resolve the inner regions of galaxies. Here we report an analysis of the stellar populations and kinematics of a lensed z = 2.1478 compact galaxy, which-surprisingly-turns out to be a fast-spinning, rotationally supported disk galaxy. Its stars must have formed in a disk, rather than in a merger-driven nuclear starburst. The galaxy was probably fed by streams of cold gas, which were able to penetrate the hot halo gas until they were cut off by shock heating from the dark matter halo. This result confirms previous indirect indications that the first galaxies to cease star formation must have gone through major changes not just in their structure, but also in their kinematics, to evolve into present-day elliptical galaxies.

  14. GMRT Low Radio Frequency Study of the Wolf Rayet Galaxy NGC ...

    Indian Academy of Sciences (India)

    with a background galaxy, 2MASX J12153795+3622218. Key words. Galaxy: radio continuum—galaxy: Wolf Rayet—individual: NGC 4214. 1. Introduction. Galaxies containing the signatures of Wolf Rayet stars such as broad He II 4686 Å emission feature in their optical spectra are known as Wolf Rayet (WR) galaxies.

  15. 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.

  16. An automatic taxonomy of galaxy morphology using unsupervised machine learning

    Science.gov (United States)

    Hocking, Alex; Geach, James E.; Sun, Yi; Davey, Neil

    2018-01-01

    We present an unsupervised machine learning technique that automatically segments and labels galaxies in astronomical imaging surveys using only pixel data. Distinct from previous unsupervised machine learning approaches used in astronomy we use no pre-selection or pre-filtering of target galaxy type to identify galaxies that are similar. We demonstrate the technique on the Hubble Space Telescope (HST) Frontier Fields. By training the algorithm using galaxies from one field (Abell 2744) and applying the result to another (MACS 0416.1-2403), we show how the algorithm can cleanly separate early and late type galaxies without any form of pre-directed training for what an 'early' or 'late' type galaxy is. We then apply the technique to the HST Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) fields, creating a catalogue of approximately 60 000 classifications. We show how the automatic classification groups galaxies of similar morphological (and photometric) type and make the classifications public via a catalogue, a visual catalogue and galaxy similarity search. We compare the CANDELS machine-based classifications to human-classifications from the Galaxy Zoo: CANDELS project. Although there is not a direct mapping between Galaxy Zoo and our hierarchical labelling, we demonstrate a good level of concordance between human and machine classifications. Finally, we show how the technique can be used to identify rarer objects and present lensed galaxy candidates from the CANDELS imaging.

  17. Discovery of two gravitationally lensed quasars with image separations of 3 arcseconds from the Sloan Digital Sky Survey

    Energy Technology Data Exchange (ETDEWEB)

    Oguri, Masamune; Inada, Naohisa; Hennawi, Joseph F.; Richards, Gordon T.; Johnston, David E.; Frieman, Joshua A.; Pindor, Bartosz; Strauss, Michael A.; Brunner, Robert; Becker, Robert H.; Castander, Francisco J.; Gregg, Michael D.; Hall, Patrick B.; Rix, Hans-Walter; Schneider, Donald P.; Bahcall, Neta A.; Brinkmann, Jonathan; York, Donald G.

    2004-11-01

    We report the discovery of two doubly-imaged quasars, SDSS J100128.61+502756.9 and SDSS J120629.65+433217.6, at redshifts of 1.838 and 1.789 and with image separations of 2.86'' and 2.90'', respectively. The objects were selected as lens candidates from the Sloan Digital Sky Survey (SDSS). Based on the identical nature of the spectra of the two quasars in each pair and the identification of the lens galaxies, we conclude that the objects are gravitational lenses. The lenses are complicated; in both systems there are several galaxies in the fields very close to the quasars, in addition to the lens galaxies themselves. The lens modeling implies that these nearby galaxies contribute significantly to the lens potentials. On larger scales, we have detected an enhancement in the galaxy density near SDSS J100128.61+502756.9. The number of lenses with image separation of {approx} 3'' in the SDSS already exceeds the prediction of simple theoretical models based on the standard Lambda-dominated cosmology and observed velocity function of galaxies.

  18. Statistical and systematic errors in the measurement of weak-lensing Minkowski functionals: Application to the Canada-France-Hawaii Lensing Survey

    Energy Technology Data Exchange (ETDEWEB)

    Shirasaki, Masato; Yoshida, Naoki, E-mail: masato.shirasaki@utap.phys.s.u-tokyo.ac.jp [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan)

    2014-05-01

    The measurement of cosmic shear using weak gravitational lensing is a challenging task that involves a number of complicated procedures. We study in detail the systematic errors in the measurement of weak-lensing Minkowski Functionals (MFs). Specifically, we focus on systematics associated with galaxy shape measurements, photometric redshift errors, and shear calibration correction. We first generate mock weak-lensing catalogs that directly incorporate the actual observational characteristics of the Canada-France-Hawaii Lensing Survey (CFHTLenS). We then perform a Fisher analysis using the large set of mock catalogs for various cosmological models. We find that the statistical error associated with the observational effects degrades the cosmological parameter constraints by a factor of a few. The Subaru Hyper Suprime-Cam (HSC) survey with a sky coverage of ∼1400 deg{sup 2} will constrain the dark energy equation of the state parameter with an error of Δw {sub 0} ∼ 0.25 by the lensing MFs alone, but biases induced by the systematics can be comparable to the 1σ error. We conclude that the lensing MFs are powerful statistics beyond the two-point statistics only if well-calibrated measurement of both the redshifts and the shapes of source galaxies is performed. Finally, we analyze the CFHTLenS data to explore the ability of the MFs to break degeneracies between a few cosmological parameters. Using a combined analysis of the MFs and the shear correlation function, we derive the matter density Ω{sub m0}=0.256±{sub 0.046}{sup 0.054}.

  19. 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

  20. Bacterial adherence to extended wear soft contact lenses

    International Nuclear Information System (INIS)

    Aswad, M.I.; John, T.; Barza, M.; Kenyon, K.; Baum, J.

    1990-01-01

    The authors studied the adherence of Pseudomonas aeruginosa and Staphylococcus aureus to extended wear soft contact lenses (EWSCLs) with and without focal deposits using both a radiolabeling technique and electron microscopy. P. aeruginosa showed significant adherence to contact lenses in vitro. In contrast, S. aureus failed to show significant adherence to contact lenses in vitro (i.e., the radioactive uptake was not significantly above background). The extent of adherence of Pseudomonas was proportional to the number of focal deposits on the lenses. Results of electron microscopic examination showed the bacteria to be adherent primarily to large focal deposits (greater than or equal to 150 microns). There was no pseudomonal adherence to the small focal deposits (less than or equal to 50 microns) and little adherence to the areas in between the focal deposits. The authors hypothesize that worn lenses, especially those with large focal deposits, serve as a vehicle for the transport of P. aeruginosa to the cornea. This hypothesis could be a partial explanation for the high incidence of keratitis caused by P. aeruginosa in EWSCL patients

  1. Ultraviolet Extinction in Backlit Galaxies - from Galaxy Zoo to GALEX

    Science.gov (United States)

    Keel, William C.; Manning, A.; Holwerda, B. W.; Lintott, C.; Schawinski, K.; Galaxy Zoo Team

    2012-01-01

    We examine the ultraviolet extinction of galaxies on large scales, combining optical and GALEX UV data on backlit galaxies (most found in the Galaxy Zoo citizen-science project). We analyze the images in matching ways, modelling both foreground and background galaxies by symmetry or elliptical isophote families as appropriate, and using the non-overlapping regions of the galaxies to estimate errors in the derived transmission T=e-κ. Spirals appear less symmetric in the UV, as star-forming regions become more dominant, so that our most reliable results are mean values across multiple regions and multiple galaxies. Our mean effective extinction curve is dominated by the contribution of luminous spirals,and shows a fairly flat gray" extinction law into the ultraviolet. For example, the median of κNUV/κB in spiral arms is only 1.3. Along with previous high-resolution HST studies of a few nearby backlit galaxies, this suggests that on kpc scales the effective extinction is dominated by the dust clumping rather than the intrinsic reddening law. This implies that extrapolation of local properties to short wavelengths, a step toward the history of dust in galaxies through comparison of local properties with a similar analysis in deep HST fields, can be done without introducing much additional error. This work was supported by NASA Astrophysics Data Analysis Program grant NNX10AD54G.

  2. Exploring cosmic origins with CORE: Extragalactic sources in cosmic microwave background maps

    Science.gov (United States)

    De Zotti, G.; González-Nuevo, J.; Lopez-Caniego, M.; Negrello, M.; Greenslade, J.; Hernández-Monteagudo, C.; Delabrouille, J.; Cai, Z.-Y.; Bonato, M.; Achúcarro, A.; Ade, P.; Allison, R.; Ashdown, M.; Ballardini, M.; Banday, A. J.; Banerji, R.; Bartlett, J. G.; Bartolo, N.; Basak, S.; Bersanelli, M.; Biesiada, M.; Bilicki, M.; Bonaldi, A.; Bonavera, L.; Borrill, J.; Bouchet, F.; Boulanger, F.; Brinckmann, T.; Bucher, M.; Burigana, C.; Buzzelli, A.; Calvo, M.; Carvalho, C. S.; Castellano, M. G.; Challinor, A.; Chluba, J.; Clements, D. L.; Clesse, S.; Colafrancesco, S.; Colantoni, I.; Coppolecchia, A.; Crook, M.; D'Alessandro, G.; de Bernardis, P.; de Gasperis, G.; Diego, J. M.; Di Valentino, E.; Errard, J.; Feeney, S. M.; Fernández-Cobos, R.; Ferraro, S.; Finelli, F.; Forastieri, F.; Galli, S.; Génova-Santos, R. T.; Gerbino, M.; Grandis, S.; Hagstotz, S.; Hanany, S.; Handley, W.; Hervias-Caimapo, C.; Hills, M.; Hivon, E.; Kiiveri, K.; Kisner, T.; Kitching, T.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamagna, L.; Lasenby, A.; Lattanzi, M.; Le Brun, A.; Lesgourgues, J.; Lewis, A.; Liguori, M.; Lindholm, V.; Luzzi, G.; Maffei, B.; Mandolesi, N.; Martinez-Gonzalez, E.; Martins, C. J. A. P.; Masi, S.; Massardi, M.; Matarrese, S.; McCarthy, D.; Melchiorri, A.; Melin, J.-B.; Molinari, D.; Monfardini, A.; Natoli, P.; Notari, A.; Paiella, A.; Paoletti, D.; Partridge, R. B.; Patanchon, G.; Piat, M.; Pisano, G.; Polastri, L.; Polenta, G.; Pollo, A.; Poulin, V.; Quartin, M.; Remazeilles, M.; Roman, M.; Rossi, G.; Roukema, B. F.; Rubiño-Martín, J.-A.; Salvati, L.; Scott, D.; Serjeant, S.; Tartari, A.; Toffolatti, L.; Tomasi, M.; Trappe, N.; Triqueneaux, S.; Trombetti, T.; Tucci, M.; Tucker, C.; Väliviita, J.; van de Weygaert, R.; Van Tent, B.; Vennin, V.; Vielva, P.; Vittorio, N.; Young, K.; Zannoni, M.

    2018-04-01

    We discuss the potential of a next generation space-borne Cosmic Microwave Background (CMB) experiment for studies of extragalactic sources. Our analysis has particular bearing on the definition of the future space project, CORE, that has been submitted in response to ESA's call for a Medium-size mission opportunity as the successor of the Planck satellite. Even though the effective telescope size will be somewhat smaller than that of Planck, CORE will have a considerably better angular resolution at its highest frequencies, since, in contrast with Planck, it will be diffraction limited at all frequencies. The improved resolution implies a considerable decrease of the source confusion, i.e. substantially fainter detection limits. In particular, CORE will detect thousands of strongly lensed high-z galaxies distributed over the full sky. The extreme brightness of these galaxies will make it possible to study them, via follow-up observations, in extraordinary detail. Also, the CORE resolution matches the typical sizes of high-z galaxy proto-clusters much better than the Planck resolution, resulting in a much higher detection efficiency; these objects will be caught in an evolutionary phase beyond the reach of surveys in other wavebands. Furthermore, CORE will provide unique information on the evolution of the star formation in virialized groups and clusters of galaxies up to the highest possible redshifts. Finally, thanks to its very high sensitivity, CORE will detect the polarized emission of thousands of radio sources and, for the first time, of dusty galaxies, at mm and sub-mm wavelengths, respectively.

  3. Interpreting the cosmic far-infrared background anisotropies using a gas regulator model

    Science.gov (United States)

    Wu, Hao-Yi; Doré, Olivier; Teyssier, Romain; Serra, Paolo

    2018-04-01

    Cosmic far-infrared background (CFIRB) is a powerful probe of the history of star formation rate (SFR) and the connection between baryons and dark matter across cosmic time. In this work, we explore to which extent the CFIRB anisotropies can be reproduced by a simple physical framework for galaxy evolution, the gas regulator (bathtub) model. This model is based on continuity equations for gas, stars, and metals, taking into account cosmic gas accretion, star formation, and gas ejection. We model the large-scale galaxy bias and small-scale shot noise self-consistently, and we constrain our model using the CFIRB power spectra measured by Planck. Because of the simplicity of the physical model, the goodness of fit is limited. We compare our model predictions with the observed correlation between CFIRB and gravitational lensing, bolometric infrared luminosity functions, and submillimetre source counts. The strong clustering of CFIRB indicates a large galaxy bias, which corresponds to haloes of mass 1012.5 M⊙ at z = 2, higher than the mass associated with the peak of the star formation efficiency. We also find that the far-infrared luminosities of haloes above 1012 M⊙ are higher than the expectation from the SFR observed in ultraviolet and optical surveys.

  4. OT2_smalhotr_3: Herschel Extreme Lensing Line Observations (HELLO)

    Science.gov (United States)

    Malhotra, S.

    2011-09-01

    We request 59.8 hours of Herschel time to observe 20 normal star-forming galaxies in the [CII] 158 micron and [OI] 63 micron lines. These galaxies lie at high redshift (1lensing, but have modest star formation rates. Therefore they represent our best chance of studying star formation and the interstellar medium in typical, common galaxies at this epoch. Redshift 1 to 3 spans the peak of both star formation activity and black hole accretion in active galactic nuclei-- a period that was crucial in shaping our modern universe. Most of this redshift range is inaccesible to ground-based observations of [CII], [OI], or both. Herschel offers the unique opportunity to study both lines with high sensitivity throughout this epoch (using HIFI for [CII] and PACS for [OI]). These two lines are the main cooling lines of the atomic medium. By measuring their fluxes, we will measure (1) the cooling efficiency of gas, (2) gas densities and temperatures near starforming regions, and (3) gas pressures, which are important to drive the winds that provide feedback to starformation processes. By combining the proposed observations with existing multiwavelength data on these objects, we will obtain as complete a picture of galaxy-scale star formation and ISM physical conditions at high redshifts as we have at z=0. Then perhaps we can understand why star formation and AGN activity peaked at this epoch. In Herschel cycle OT1, 49 high redshift IR luminous galaxies were approved for spectroscopy, but only two so-called normal galaxies were included. This is an imbalance that should be corrected, to balance Herschel's legacy.

  5. Use of Scleral Lenses and Miniscleral Lenses After Penetrating Keratoplasty.

    Science.gov (United States)

    Barnett, Melissa; Lien, Vivian; Li, Jennifer Y; Durbin-Johnson, Blythe; Mannis, Mark J

    2016-05-01

    To examine the clinical outcomes of scleral lenses for visual rehabilitation after penetrating keratoplasty (PK). A retrospective review was conducted for 34 patients (48 eyes) who had a history of prior PK and were fit with scleral lenses between October 2009 and December 2013 at the UC Davis Eye Center. The most common initial indication for PK was keratoconus in 27 eyes (56%). Thirty-three eyes (69%) had previously been fit with other types of contact lenses, with small-diameter rigid gas-permeable lenses being the most common. The improvement in best-corrected visual acuity with a scleral lens compared with prior spectacle refraction or other contact lens was a mean of two best-corrected visual acuity lines. Forty-four eyes (91.7%) achieved functional vision with best scleral lens-corrected visual acuities of 20/40 or better. Patients who continued wearing scleral lenses were significantly more likely to report "good" subjective vision compared with patients who abandoned scleral lens wear (P=0.009), although change in objective best-corrected visual acuity did not differ significantly. There were no cases of infectious keratitis. Six eyes (12.5%) developed graft rejection; 3 were able to resume scleral lens wear. Nineteen eyes (39.5%) discontinued scleral lens wear for various reasons, the most common reason for discontinuation of lens wear was difficulty with scleral lens insertion or removal (8 eyes, 42.1%). Scleral lenses are effective and safe in patients who have had PK. There was a mean gain in visual acuity, with the majority of patients achieving 20/40 vision or better. The patient's subjective perception of vision was a significant factor in determining whether scleral lens wear was continued or abandoned.

  6. Strongly lensed gravitational waves and electromagnetic signals as powerful cosmic rulers

    Science.gov (United States)

    Wei, Jun-Jie; Wu, Xue-Feng

    2017-12-01

    In this paper, we discuss the possibility of using strongly lensed gravitational waves (GWs) and their electromagnetic (EM) counterparts as powerful cosmic rulers. In the EM domain, it has been suggested that joint observations of the time delay (Δτ) between lensed quasar images and the velocity dispersion (σ) of the lensing galaxy (i.e. the combination Δτ/σ2) are able to constrain the cosmological parameters more strongly than Δτ or σ2 separately. Here, for the first time, we propose that this Δτ/σ2 method can be applied to the strongly lensed systems observed in both GW and EM windows. Combining the redshifts, images and σ observed in the EM domain with the very precise Δτ derived from lensed GW signals, we expect that accurate multimessenger cosmology can be achieved in the era of third-generation GW detectors. Comparing with the constraints from the Δτ method, we prove that using Δτ/σ2 can improve the discrimination between cosmological models. Furthermore, we demonstrate that with ∼50 strongly lensed GW-EM systems, we can reach a constraint on the dark energy equation of state w comparable to the 580 Union2.1 Type Ia supernovae data. Much more stringent constraints on w can be obtained when combining the Δτ and Δτ/σ2 methods.

  7. Scleral lenses: a literature review.

    Science.gov (United States)

    Schornack, Muriel M

    2015-01-01

    To present a comprehensive review of current and historical literature on scleral lenses. A comprehensive search of several databases from each database's earliest inception to May 23, 2014 was conducted by an experienced librarian with input from the author to locate articles related to scleral lens design, fabrication, prescription, and management. A total of 899 references were identified, 184 of which were directly related to scleral lenses. References of interest were organized by date, topic, and study design. Most of articles published before 1983 presented lens design and fabrication techniques or indications for scleral lens therapy. Case reviews published after 1983 identified major indications for scleral lenses (corneal ectasia, ocular surface disease, and refractive error) and visual and functional outcomes of scleral lens wear. Statistically significant improvements in visual acuity, vision-related quality of life, and ocular surface integrity were reported. Reviews of ocular and systemic conditions suggested that comprehensive management strategies for these conditions could include scleral lenses. Early work investigating scleral lens fitting characteristics, optical qualities, and potential physiological impact on anterior ocular structures have been published in the past 5 years. Indications for scleral lens wear are well-established. Developing areas of research on the physiologic impact of scleral lens wear on the ocular surface, the use of technology to improve scleral lens vision and fit, and the impact of these devices on the quality of life should further enhance our understanding of scleral lenses in the future.

  8. Deficiency of normal galaxies among Markaryan galaxies

    International Nuclear Information System (INIS)

    Iyeveer, M.M.

    1986-01-01

    Comparison of the morphological types of Markaryan galaxies and other galaxies in the Uppsala catalog indicates a strong deficiency of normal ellipticals among the Markaryan galaxies, for which the fraction of type E galaxies is ≤ 1% against 10% among the remaining galaxies. Among the Markaryan galaxies, an excess of barred galaxies is observed - among the Markaryan galaxies with types Sa-Scd, approximately half or more have bars, whereas among the remaining galaxies of the same types bars are found in about 1/3

  9. Precise LIGO lensing rate predictions for binary black holes

    Science.gov (United States)

    Ng, Ken K. Y.; Wong, Kaze W. K.; Broadhurst, Tom; Li, Tjonnie G. F.

    2018-01-01

    We show how LIGO is expected to detect coalescing binary black holes at z >1 that are lensed by the intervening galaxy population. Gravitational magnification, μ , strengthens gravitational-wave signals by √{μ } without altering their frequencies, which if unrecognized leads to an underestimate of the event redshift and hence an overestimate of the binary mass. High magnifications can be reached for coalescing binaries, because the region of intense gravitational-wave emission during coalescence is so small (˜100 km ), permitting very close projections between lensing caustics and gravitational-wave events. Our simulations use the current LIGO event-based mass function and incorporate accurate waveforms convolved with the LIGO power spectral density. Importantly, we include the detection dependence on sky position and orbital orientation, which for the LIGO configuration translates into a wide spread in observed redshifts and chirp masses. Currently, we estimate a detectable rate of lensed events 0. 06-0.02+0.02 yr-1 that rises to 5-3+5 yr-1 at LIGO design sensitivity limit, depending on the high redshift rate of black hole coalescence.

  10. Contact Lenses for Keratoconus- Current Practice

    Science.gov (United States)

    Moschos, Marilita M.; Nitoda, Eirini; Georgoudis, Panagiotis; Balidis, Miltos; Karageorgiadis, Eleftherios; Kozeis, Nikos

    2017-01-01

    Background: Keratoconus is a chronic, bilateral, usuallly asymmetrical, non-inflammatory, ectatic disorder, being characterized by progressive steepening, thinning and apical scarring of the cornea. Initially, the patient is asymptomatic, but the visual acuity gradually decreases, resulting in significant vision loss due to the development of irregular astigmatism, myopia, corneal thinning and scarring. The classic treatment of visual rehabilitation in keratoconus is based on spectacles and contact lenses (CLs). Objective: To summarize the types of CLs used in the treatment of keratoconus. This is literature review of several important published articles focusing on the visual rehabilitation in keratoconus with CLs. Method: Gas permeable (GP) CLs have been found to achieve better best corrected visual acuity than spectacles, eliminating 3rd-order coma root-mean-square (RMS) error, 3rd-order RMS, and higher-order RMS. However, they have implicated in reduction of corneal basal epithelial cell and anterior stromal keratocyte densities. Soft CLs seem to provide greater comfort and lower cost, but the low oxygen permeability (if the lens is not a silicone hydrogel), and the inability to mask moderate to severe irregular astigmatism are the main disadvantages of them. On the other hand, scleral CLs ensure stable platforms, which eliminate high-order aberrations and provide good centration and visual acuity. Their main disadvantages include the difficulties in application and removal of these lenses along with corneal flattening and swelling. Result: The modern hybrid CLs are indicated in cases of poor centration, poor stability or intolerance with GP lenses. Finally, piggyback CL systems effectively ameliorate visual acuity, but they have been related to corneal neovascularization and giant papillary conjunctivitis. Conclusion: CLs seem to rehabilitate visual performance, diminishing the power of the cylinder and the high-order aberrations. The final choice of CLs is

  11. HOW TO FIND GRAVITATIONALLY LENSED TYPE Ia SUPERNOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, Daniel A.; Nugent, Peter E. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

    2017-01-01

    Type Ia supernovae (SNe Ia) that are multiply imaged by gravitational lensing can extend the SN Ia Hubble diagram to very high redshifts ( z ≳ 2), probe potential SN Ia evolution, and deliver high-precision constraints on H {sub 0}, w , and Ω{sub m} via time delays. However, only one, iPTF16geu, has been found to date, and many more are needed to achieve these goals. To increase the multiply imaged SN Ia discovery rate, we present a simple algorithm for identifying gravitationally lensed SN Ia candidates in cadenced, wide-field optical imaging surveys. The technique is to look for supernovae that appear to be hosted by elliptical galaxies, but that have absolute magnitudes implied by the apparent hosts’ photometric redshifts that are far brighter than the absolute magnitudes of normal SNe Ia (the brightest type of supernovae found in elliptical galaxies). Importantly, this purely photometric method does not require the ability to resolve the lensed images for discovery. Active galactic nuclei, the primary sources of contamination that affect the method, can be controlled using catalog cross-matches and color cuts. Highly magnified core-collapse SNe will also be discovered as a byproduct of the method. Using a Monte Carlo simulation, we forecast that the Large Synoptic Survey Telescope can discover up to 500 multiply imaged SNe Ia using this technique in a 10 year z -band search, more than an order of magnitude improvement over previous estimates. We also predict that the Zwicky Transient Facility should find up to 10 multiply imaged SNe Ia using this technique in a 3 year R -band search—despite the fact that this survey will not resolve a single system.

  12. ROSAT Discovers Unique, Distant Cluster of Galaxies

    Science.gov (United States)

    1995-06-01

    galaxies as they were 5,000 million years ago. Knowing the intensity of the X-ray emission as measured by ROSAT and also the distance, the astronomers were then able to estimate the total X-ray energy emitted by this cluster. It was found to be extremely high [3], in fact higher than that of any other cluster ever observed by ROSAT. It amounts to no less than 1.5 million million times the total energy emitted by the Sun. It is believed that this strong X-ray emission originates in a hot gas located between the galaxies in the cluster. The high temperature indicates that the components of the gas move very rapidly; this is related to the strong gravitational field within the cluster. THE GRAVITATIONAL ARCS To their great surprise and delight, the astronomers also discovered two bright arcs, 5 - 6 arcseconds long and symmetrically placed about 35 arcseconds to the North-East and South-West of the brightest galaxies in the cluster (see the photo). They were detected on exposures of only 3 minutes duration with the 2.2-metre telescope and are among the brightest such arcs ever found. At the indicated distance, the arcs are situated at a projected distance of about 500,000 light-years from the centre of the cluster. It is an interesting possibility that the two arcs may in fact be two images of the same, very distant galaxy, that is situated far beyond RXJ1347.5-1145 and whose light has been bent and split by this cluster's strong gravitational field. This strange phenomenon was first discovered in the late 1970's and is referred to as gravitational lensing. Quite a few examples are now known, in most cases in the form of double or multiple images of quasars. About three dozen cases involve well visible galaxy clusters and elongated arcs, but few, if any, of these arcs are as bright as those seen in the present cluster. This particular arc configuration enables a very accurate determination of the total mass of the cluster, once the distance of the background galaxy has been

  13. 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.

  14. Gravitational lensing by exotic objects

    Science.gov (United States)

    Asada, Hideki

    2017-11-01

    This paper reviews a phenomenological approach to the gravitational lensing by exotic objects such as the Ellis wormhole lens, where the exotic lens objects may follow a non-standard form of the equation of state or may obey a modified gravity theory. A gravitational lens model is proposed in the inverse powers of the distance, such that the Schwarzschild lens and exotic lenses can be described in a unified manner as a one parameter family. As observational implications, the magnification, shear, photo-centroid motion and time delay in this lens model are discussed.

  15. 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.

  16. 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.; 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.

    2018-01-01

    With the advent of wide-area submillimeter surveys, a large number of high-redshift gravitationally lensed dusty star-forming galaxies (DSFGs) has been revealed. Due to the simplicity of the selection criteria for candidate lensed sources in such surveys, identified as those with S500μm > 100 mJy, uncertainties associated with the modelling of the selection function are expunged. The combination of these attributes makes submillimeter 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 Millimetre 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 which contains both dark matter and baryons. We used three different density distributions, one based on analytical fits to the halos 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 ˜1013M⊙ for the SIS and SISSA models, above which we assumed that the density distribution could be represented by an NFW 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.

  17. The Sloan Lens ACS Survey. I. A large spectroscopically selected sample of massive early-type lens galaxies

    NARCIS (Netherlands)

    Bolton, AS; Burles, S; Koopmans, LVE; Treu, T; Moustakas, LA

    2006-01-01

    The Sloan Lens ACS (SLACS) Survey is an efficient Hubble Space Telescope (HST) Snapshot imaging survey for new galaxy-scale strong gravitational lenses. The targeted lens candidates are selected spectroscopically from the Sloan Digital Sky Survey (SDSS) database of galaxy spectra for having multiple

  18. Mapping Dark Matter in Simulated Galaxy Clusters

    Science.gov (United States)

    Bowyer, Rachel

    2018-01-01

    Galaxy clusters are the most massive bound objects in the Universe with most of their mass being dark matter. Cosmological simulations of structure formation show that clusters are embedded in a cosmic web of dark matter filaments and large scale structure. It is thought that these filaments are found preferentially close to the long axes of clusters. We extract galaxy clusters from the simulations "cosmo-OWLS" in order to study their properties directly and also to infer their properties from weak gravitational lensing signatures. We investigate various stacking procedures to enhance the signal of the filaments and large scale structure surrounding the clusters to better understand how the filaments of the cosmic web connect with galaxy clusters. This project was supported in part by the NSF REU grant AST-1358980 and by the Nantucket Maria Mitchell Association.

  19. 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

  20. Large-scale galaxy bias

    Science.gov (United States)

    Jeong, Donghui; Desjacques, Vincent; Schmidt, Fabian

    2018-01-01

    Here, we briefly introduce the key results of the recent review (arXiv:1611.09787), whose abstract is as following. This review presents a comprehensive overview of galaxy bias, that is, the statistical relation between the distribution of galaxies and matter. We focus on large scales where cosmic density fields are quasi-linear. On these scales, the clustering of galaxies can be described by a perturbative bias expansion, and the complicated physics of galaxy formation is absorbed by a finite set of coefficients of the expansion, called bias parameters. The review begins with a detailed derivation of this very important result, which forms the basis of the rigorous perturbative description of galaxy clustering, under the assumptions of General Relativity and Gaussian, adiabatic initial conditions. Key components of the bias expansion are all leading local gravitational observables, which include the matter density but also tidal fields and their time derivatives. We hence expand the definition of local bias to encompass all these contributions. This derivation is followed by a presentation of the peak-background split in its general form, which elucidates the physical meaning of the bias parameters, and a detailed description of the connection between bias parameters and galaxy (or halo) statistics. We then review the excursion set formalism and peak theory which provide predictions for the values of the bias parameters. In the remainder of the review, we consider the generalizations of galaxy bias required in the presence of various types of cosmological physics that go beyond pressureless matter with adiabatic, Gaussian initial conditions: primordial non-Gaussianity, massive neutrinos, baryon-CDM isocurvature perturbations, dark energy, and modified gravity. Finally, we discuss how the description of galaxy bias in the galaxies' rest frame is related to clustering statistics measured from the observed angular positions and redshifts in actual galaxy catalogs.

  1. Large-scale galaxy bias

    Science.gov (United States)

    Desjacques, Vincent; Jeong, Donghui; Schmidt, Fabian

    2018-02-01

    This review presents a comprehensive overview of galaxy bias, that is, the statistical relation between the distribution of galaxies and matter. We focus on large scales where cosmic density fields are quasi-linear. On these scales, the clustering of galaxies can be described by a perturbative bias expansion, and the complicated physics of galaxy formation is absorbed by a finite set of coefficients of the expansion, called bias parameters. The review begins with a detailed derivation of this very important result, which forms the basis of the rigorous perturbative description of galaxy clustering, under the assumptions of General Relativity and Gaussian, adiabatic initial conditions. Key components of the bias expansion are all leading local gravitational observables, which include the matter density but also tidal fields and their time derivatives. We hence expand the definition of local bias to encompass all these contributions. This derivation is followed by a presentation of the peak-background split in its general form, which elucidates the physical meaning of the bias parameters, and a detailed description of the connection between bias parameters and galaxy statistics. We then review the excursion-set formalism and peak theory which provide predictions for the values of the bias parameters. In the remainder of the review, we consider the generalizations of galaxy bias required in the presence of various types of cosmological physics that go beyond pressureless matter with adiabatic, Gaussian initial conditions: primordial non-Gaussianity, massive neutrinos, baryon-CDM isocurvature perturbations, dark energy, and modified gravity. Finally, we discuss how the description of galaxy bias in the galaxies' rest frame is related to clustering statistics measured from the observed angular positions and redshifts in actual galaxy catalogs.

  2. A new detection of an UFO in the X-ray spectrum of a lensed QSO

    Science.gov (United States)

    Dadina, M.

    2017-10-01

    The discovery of the "M_{SMBH}-σ relation" indicated that a connection between the central black-hole and the hosting galaxies acted during the cosmic time. With the discovery in X-rays of the ultra-fast outflows in nearby AGN, we have most probably probed one of the ingredients that are needed to build-up this mechanism. At high-z, however, such measurements were possible only in an handful of objects and this was possible mainly for the presence of gravitational lenses that magnified otherwise X-ray weak QSO. Following this, we proposed a program to use XMM-Newton and gravitational lenses as telescopes to point bright, lensed and distant QSO to characterize in detail their X-ray spectrum and to detect blushifted absorption lines at E˜7-10 keV (rest frame). Here we present the preliminary results obtained for the z=2.64 QSO MG J0414+0534.

  3. 3D weak lensing with spin wavelets on the ball

    Science.gov (United States)

    Leistedt, Boris; McEwen, Jason D.; Kitching, Thomas D.; Peiris, Hiranya V.

    2015-12-01

    We construct the spin flaglet transform, a wavelet transform to analyze spin signals in three dimensions. Spin flaglets can probe signal content localized simultaneously in space and frequency and, moreover, are separable so that their angular and radial properties can be controlled independently. They are particularly suited to analyzing cosmological observations such as the weak gravitational lensing of galaxies. Such observations have a unique 3D geometrical setting since they are natively made on the sky, have spin angular symmetries, and are extended in the radial direction by additional distance or redshift information. Flaglets are constructed in the harmonic space defined by the Fourier-Laguerre transform, previously defined for scalar functions and extended here to signals with spin symmetries. Thanks to various sampling theorems, both the Fourier-Laguerre and flaglet transforms are theoretically exact when applied to bandlimited signals. In other words, in numerical computations the only loss of information is due to the finite representation of floating point numbers. We develop a 3D framework relating the weak lensing power spectrum to covariances of flaglet coefficients. We suggest that the resulting novel flaglet weak lensing estimator offers a powerful alternative to common 2D and 3D approaches to accurately capture cosmological information. While standard weak lensing analyses focus on either real- or harmonic-space representations (i.e., correlation functions or Fourier-Bessel power spectra, respectively), a wavelet approach inherits the advantages of both techniques, where both complicated sky coverage and uncertainties associated with the physical modeling of small scales can be handled effectively. Our codes to compute the Fourier-Laguerre and flaglet transforms are made publicly available.

  4. Only marginal alignment of disc galaxies

    Science.gov (United States)

    Andrae, René; Jahnke, Knud

    2011-12-01

    Testing theories of angular-momentum acquisition of rotationally supported disc galaxies is the key to understanding the formation of this type of galaxies. The tidal-torque theory aims to explain this acquisition process in a cosmological framework and predicts positive autocorrelations of angular-momentum orientation and spiral-arm handedness, i.e. alignment of disc galaxies, on short distance scales of 1 Mpc h-1. This disc alignment can also cause systematic effects in weak-lensing measurements. Previous observations claimed discovering these correlations but are overly optimistic in the reported level of statistical significance of the detections. Errors in redshift, ellipticity and morphological classifications were not taken into account, although they have a significant impact. We explain how to rigorously propagate all the important errors through the estimation process. Analysing disc galaxies in the Sloan Digital Sky Survey (SDSS) data base, we find that positive autocorrelations of spiral-arm handedness and angular-momentum orientations on distance scales of 1 Mpc h-1 are plausible but not statistically significant. Current data appear not good enough to constrain parameters of theory. This result agrees with a simple hypothesis test in the Local Group, where we also find no evidence for disc alignment. Moreover, we demonstrate that ellipticity estimates based on second moments are strongly biased by galactic bulges even for Scd galaxies, thereby corrupting correlation estimates and overestimating the impact of disc alignment on weak-lensing studies. Finally, we discuss the potential of future sky surveys. We argue that photometric redshifts have too large errors, i.e. PanSTARRS and LSST cannot be used. Conversely, the EUCLID project will not cover the relevant redshift regime. We also discuss the potentials and problems of front-edge classifications of galaxy discs in order to improve the autocorrelation estimates of angular-momentum orientation.

  5. COMBINED EFFECTS OF GALAXY INTERACTIONS AND LARGE-SCALE ENVIRONMENT ON GALAXY PROPERTIES

    International Nuclear Information System (INIS)

    Park, Changbom; Choi, Yun-Young

    2009-01-01

    We inspect the coupled dependence of physical parameters of the Sloan Digital Sky Survey galaxies on the small-scale (distance to and morphology of the nearest neighbor galaxy) and the large-scale (background density smoothed over 20 nearby galaxies) environments. The impacts of interaction on galaxy properties are detected at least out to the neighbor separation corresponding to the virial radius of galaxies, which is typically between 200 and 400 h -1 kpc for the galaxies in our sample. To detect these long-range interaction effects, it is crucial to divide galaxy interactions into four cases dividing the morphology of target and neighbor galaxies into early and late types. We show that there are two characteristic neighbor-separation scales where the galaxy interactions cause abrupt changes in the properties of galaxies. The first scale is the virial radius of the nearest neighbor galaxy r vir,nei . Many physical parameters start to deviate from those of extremely isolated galaxies at the projected neighbor separation r p of about r vir,nei . The second scale is at r p ∼ 0.05r vir,nei = 10-20 h -1 kpc, and is the scale at which the galaxies in pairs start to merge. We find that late-type neighbors enhance the star formation activity of galaxies while early-type neighbors reduce it, and that these effects occur within r vir,nei . The hot halo gas and cold disk gas must be participating in the interactions at separations less than the virial radius of the galaxy plus dark halo system. Our results also show that the role of the large-scale density in determining galaxy properties is minimal once luminosity and morphology are fixed. We propose that the weak residual dependence of galaxy properties on the large-scale density is due to the dependence of the halo gas property on the large-scale density.

  6. 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

  7. 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…

  8. Polarization optics of GRIN lenses

    Science.gov (United States)

    Camacho, Javier; Tentori, Diana

    2001-01-01

    In this paper we show that the matrix representation for a linear retarder, given by Jones calculus, can be successfully applied to describe the birefringence properties of GRIN lenses for meridional rays. The usefulness of this description is experimentally verified by comparing the output pattern of a GRIN lens obtained in a linear polariscope with the predicted conoscopic pattern.

  9. Galactic rings revisited - I. CVRHS classifications of 3962 ringed galaxies from the Galaxy Zoo 2 Database

    Science.gov (United States)

    Buta, Ronald J.

    2017-11-01

    Rings are important and characteristic features of disc-shaped galaxies. This paper is the first in a series that re-visits galactic rings with the goals of further understanding the nature of the features and for examining their role in the secular evolution of galaxy structure. The series begins with a new sample of 3962 galaxies drawn from the Galaxy Zoo 2 citizen science data base, selected because zoo volunteers recognized a ring-shaped pattern in the morphology as seen in Sloan Digital Sky Survey colour images. The galaxies are classified within the framework of the Comprehensive de Vaucouleurs revised Hubble-Sandage system. It is found that zoo volunteers cued on the same kinds of ring-like features that were recognized in the 1995 Catalogue of Southern Ringed Galaxies. This paper presents the full catalogue of morphological classifications, comparisons with other sources of classifications and some histograms designed mainly to highlight the content of the catalogue. The advantages of the sample are its large size and the generally good quality of the images; the main disadvantage is the low physical resolution that limits the detectability of linearly small rings such as nuclear rings. The catalogue includes mainly inner and outer disc rings and lenses. Cataclysmic (`encounter-driven') rings (such as ring and polar ring galaxies) are recognized in less than 1 per cent of the sample.

  10. 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.

    2018-03-01

    We present the discovery of 3 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″ 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″ 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 3 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.

  11. Glutathione preservation during storage of rat lenses in optisol-GS and castor oil.

    Directory of Open Access Journals (Sweden)

    Thomas Holm

    Full Text Available BACKGROUND: Glutathione concentration in the lens decreases in aging and cataractous lenses, providing a marker for tissue condition. Experimental procedures requiring unfrozen lenses from donor banks rely on transportation in storage medium, affecting lens homeostasis and alterations in glutathione levels. The aim of the study was to examine the effects of Optisol-GS and castor oil on lens condition, determined from their ability to maintain glutathione concentrations. METHODOLOGY/PRINCIPAL FINDINGS: Rat lenses were stored in the two types of storage media at varying time intervals up to 3 days. Glutathione concentration was afterwards determined in an enzymatic detection assay, specific for both reduced and oxidized forms. Lenses removed immediately after death exhibited a glutathione concentration of 4.70±0.29 mM. In vitro stored lenses in Optisol-GS lost glutathione quickly, ending with a concentration of 0.60±0.34 mM after 3 days while castor oil stored lenses exhibited a slower decline and ended at 3 times the concentration. A group of lenses were additionally stored under post mortem conditions within the host for 6 hours before its removal. Total glutathione after 6 hours was similar to that of lenses removed immediately after death, but with altered GSH and GSSG concentrations. Subsequent storage of these lenses in media showed changes similar to those in the first series of experiments, albeit to a lesser degree. CONCLUSIONS/SIGNIFICANCE: It was determined that storage in Optisol-GS resulted in a higher loss of glutathione than lenses stored in castor oil. Storage for more than 12 hours reduced glutathione to half its original concentration, and was considered unusable after 24 hours.

  12. S0 galaxies in Formax

    DEFF Research Database (Denmark)

    Bedregal...[], A. G.; Aragón-Salamanca, A.; Merrifield, M. R.

    2006-01-01

    Galaxies: elliptical and lenticular, cD: galaxies: kinematics and dynamics Udgivelsesdato: Oct.1......Galaxies: elliptical and lenticular, cD: galaxies: kinematics and dynamics Udgivelsesdato: Oct.1...

  13. Pathogenic Free-Living Amoebae Isolated From Contact Lenses of Keratitis Patients

    OpenAIRE

    HAJIALILO, Elham; NIYYATI, Maryam; SOLAYMANI, Mohammad; REZAEIAN, Mostafa

    2015-01-01

    Background: Free-living amoeba (FLA)-related keratitis is a progressive infection of the cornea with poor prognosis. The present study aimed to investigates the con­tact lenses of patients with keratitis for pathogenic free-living amoebae.Methods: Overall, 62 contact lenses and their paraphernalia of patients with kerati­tis cultured and tested for the presence of free-living amoebae using morphological criteria. Unusual plates including plates containing mix amoebae and Vermamoeba were submi...

  14. Microbial contamination of soft contact lenses & accessories in asymptomatic contact lens users

    OpenAIRE

    Deeksha V Thakur; Ujjwala N Gaikwad

    2014-01-01

    Background & objectives: With increasing use of soft contact lenses the incidence of contact lens induced infections is also increasing. This study was aimed to assess the knowledge of new and existing contact lens users about the risk of microbial contamination associated with improper use and maintenance of contact lenses, type of microbial flora involved and their potential to cause ophthalmic infections. Methods: Four samples each from 50 participants (n=200) were collected from the l...

  15. CCD photometry of apparent dwarf galaxies in Fornax

    International Nuclear Information System (INIS)

    Phillipps, S.; Grimley, P.L.; Disney, M.J.; Cawson, M.G.M.; Kibblewhite, E.J.

    1986-01-01

    Blue and red CCD surface photometry of two apparent dwarf galaxies in the Fornax cluster region is presented. Luminosity profiles are derived and their form discussed. The fainter galaxy resembles an archetypal diffuse dwarf elliptical but the brighter of the pair is either an unusual red dwarf or a background galaxy in chance juxtaposition. (author)

  16. Weak gravitational lensing as a method to constrain unstable dark matter

    International Nuclear Information System (INIS)

    Wang Meiyu; Zentner, Andrew R.

    2010-01-01

    The nature of the dark matter remains a mystery. The possibility of an unstable dark matter particle decaying to invisible daughter particles has been explored many times in the past few decades. Meanwhile, weak gravitational lensing shear has gained a lot of attention as a probe of dark energy, though it was previously considered a dark matter probe. Weak lensing is a useful tool for constraining the stability of the dark matter. In the coming decade a number of large galaxy imaging surveys will be undertaken and will measure the statistics of cosmological weak lensing with unprecedented precision. Weak lensing statistics are sensitive to unstable dark matter in at least two ways. Dark matter decays alter the matter power spectrum and change the angular diameter distance-redshift relation. We show how measurements of weak lensing shear correlations may provide the most restrictive, model-independent constraints on the lifetime of unstable dark matter. Our results rely on assumptions regarding nonlinear evolution of density fluctuations in scenarios of unstable dark matter and one of our aims is to stimulate interest in theoretical work on nonlinear structure growth in unstable dark matter models.

  17. 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.

  18. CLASH: EXTREME EMISSION-LINE GALAXIES AND THEIR IMPLICATION ON SELECTION OF HIGH-REDSHIFT GALAXIES

    International Nuclear Information System (INIS)

    Huang, Xingxing; Wang, Junxian; Shu, Xinwen; Zheng, Wei; Ford, Holland; Lemze, Doron; Moustakas, John; Van der Wel, Arjen; Zitrin, Adi; Frye, Brenda L.; Postman, Marc; Bradley, Larry; Coe, Dan; Bartelmann, Matthias; Benítez, Narciso; Broadhurst, Tom; Donahue, Megan; Infante, Leopoldo

    2015-01-01

    We utilize the Cluster Lensing And Supernova survey with Hubble observations of 25 clusters to search for extreme emission-line galaxies (EELGs). The selections are carried out in two central bands: F105W (Y 105 ) and F125W (J 125 ), as the flux of the central bands could be enhanced by the presence of [O III] λλ4959, 5007 at redshifts of ∼0.93-1.14 and 1.57-1.79, respectively. The multiband observations help to constrain the equivalent widths (EWs) of emission lines. Thanks to cluster lensing, we are able to identify 52 candidates down to an intrinsic limiting magnitude of 28.5 and to a rest-frame [O III] λλ4959, 5007 EW of ≅ 3700 Å. Our samples include a number of EELGs at lower luminosities that are missed in other surveys, and the extremely high EW can only be found in such faint galaxies. These EELGs can mimic a dropout feature similar to that of high-redshift galaxies and contaminate the color-color selection of high-redshift galaxies when the signal-to-noise ratio is limited or the band coverage is incomplete

  19. CLASH: EXTREME EMISSION-LINE GALAXIES AND THEIR IMPLICATION ON SELECTION OF HIGH-REDSHIFT GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xingxing; Wang, Junxian; Shu, Xinwen [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zheng, Wei; Ford, Holland; Lemze, Doron [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Moustakas, John [Department of Physics and Astronomy, Siena College, 515 Loudon Road, Loudonville, NY 12211 (United States); Van der Wel, Arjen [Max-Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg (Germany); Zitrin, Adi [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Frye, Brenda L. [Steward Observatory/Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Postman, Marc; Bradley, Larry; Coe, Dan [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21208 (United States); Bartelmann, Matthias [Leiden Observatory, Leiden University, P. O. Box 9513, 2300 RA Leiden (Netherlands); Benítez, Narciso [Instituto de Astrofísica de Andalucía (CSIC), C/Camino Bajo de Huétor 24, Granada E-18008 (Spain); Broadhurst, Tom [Department of Theoretical Physics, University of Basque Country UPV/EHU E-Bilbao (Spain); Donahue, Megan [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Infante, Leopoldo, E-mail: hxx@mail.ustc.edu.cn [Departamento de Astronoía y Astrofísica, Pontificia Universidad Católica de Chile, V. Mackenna 4860 Santiago 22 (Chile); and others

    2015-03-01

    We utilize the Cluster Lensing And Supernova survey with Hubble observations of 25 clusters to search for extreme emission-line galaxies (EELGs). The selections are carried out in two central bands: F105W (Y {sub 105}) and F125W (J {sub 125}), as the flux of the central bands could be enhanced by the presence of [O III] λλ4959, 5007 at redshifts of ∼0.93-1.14 and 1.57-1.79, respectively. The multiband observations help to constrain the equivalent widths (EWs) of emission lines. Thanks to cluster lensing, we are able to identify 52 candidates down to an intrinsic limiting magnitude of 28.5 and to a rest-frame [O III] λλ4959, 5007 EW of ≅ 3700 Å. Our samples include a number of EELGs at lower luminosities that are missed in other surveys, and the extremely high EW can only be found in such faint galaxies. These EELGs can mimic a dropout feature similar to that of high-redshift galaxies and contaminate the color-color selection of high-redshift galaxies when the signal-to-noise ratio is limited or the band coverage is incomplete.

  20. Mapping stellar content to dark matter halos - III. Environmental dependence and conformity of galaxy colours

    Science.gov (United States)

    Zu, Ying; Mandelbaum, Rachel

    2018-02-01

    Recent studies suggest that the quenching properties of galaxies are correlated over several mega-parsecs. The large-scale "galactic conformity" phenomenon around central galaxies has been regarded as a potential signature of "galaxy assembly bias" or "pre-heating", both of which interpret conformity as a result of direct environmental effects acting on galaxy formation. Building on the iHOD halo quenching framework developed in Zu & Mandelbaum (2015, 2016), we discover that our fiducial halo mass quenching model, without any galaxy assembly bias, can successfully explain the overall environmental dependence and the conformity of galaxy colours in SDSS, as measured by the mark correlation functions of galaxy colours and the red galaxy fractions around isolated primaries, respectively. Our fiducial iHOD halo quenching mock also correctly predicts the differences in the spatial clustering and galaxy-galaxy lensing signals between the more vs. less red galaxy subsamples, split by the red-sequence ridge-line at fixed stellar mass. Meanwhile, models that tie galaxy colours fully or partially to halo assembly bias have difficulties in matching all these observables simultaneously. Therefore, we demonstrate that the observed environmental dependence of galaxy colours can be naturally explained by the combination of 1) halo quenching and 2) the variation of halo mass function with environment — an indirect environmental effect mediated by two separate physical processes.

  1. Gravitational lensing by rotating wormholes

    Science.gov (United States)

    Jusufi, Kimet; Ã-vgün, Ali

    2018-01-01

    In this paper the deflection angle of light by a rotating Teo wormhole spacetime is calculated in the weak limit approximation. We mainly focus on the weak deflection angle by revealing the gravitational lensing as a partially global topological effect. We apply the Gauss-Bonnet theorem (GBT) to the optical geometry osculating the Teo-Randers wormhole optical geometry to calculate the deflection angle. Furthermore we find the same result using the standard geodesic method. We have found that the deflection angle can be written as a sum of two terms, namely the first term is proportional to the throat of the wormhole and depends entirely on the geometry, while the second term is proportional to the spin angular momentum parameter of the wormhole. A direct observation using lensing can shed light and potentially test the nature of rotating wormholes by comparing with the black holes systems.

  2. 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

  3. Polycapillary neutron lenses

    International Nuclear Information System (INIS)

    Mildner, D.F.R.

    1997-01-01

    The principle of multiple mirror reflection from smooth surfaces at small grazing angles enables the transport and guiding of high intensity slow neutron beams to locations of low background for neutron scattering and absorption experiments and to provide facilities for multiple instruments. Curved guides have been widely used at cold neutron facilities to remove the unwanted radiation (fast neutrons and gamma rays) from the beam without the use of filters. A typical guide has transverse dimensions of 50 mm and, with a radius of curvature of 1 km, transmits wavelengths longer than 5 A. Much tighter curves requires narrower transverse dimensions, otherwise there is little transmission. Typical neutron benders have a number of slots with transverse dimensions of ∼5 mm. Based on the same principle but using a different technology, recent developments in glass polycapillary fibers have produced miniature versions of neutron guides. Fibers with many thousands of channels having sizes of ∼ 10 μm enable beams of long wavelength neutrons (λ > 4 A) to be transmitted efficiently in a radius of curvature as small as a fraction of 1 m. A large collection of these miniature versions of neutron guides can be used to bend the neutron trajectories such that the incident beam can be focused. (author)

  4. Crashing galaxies, cosmic fireworks

    International Nuclear Information System (INIS)

    Keel, W.C.

    1989-01-01

    The study of binary systems is reviewed. The history of the study of interacting galaxies, the behavior of gas in binary systems, studies to identify the processes that occur when galaxies interact, and the relationship of Seyfert galaxies and quasars to binary systems are discussed. The development of an atlas of peculiar galaxies (Arp, 1966) and methods for modeling galaxy interactions are examined

  5. 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...

  6. Galaxy Zoo: A Catalog of Overlapping Galaxy Pairs for Dust Studies

    OpenAIRE

    Keel, William C.; Manning, Anna; Holwerda, Benne W.; Mezzoprete, Massimo; Lintott, Chris J.; Schawinski, Kevin; Gay, Pamela; Masters, Karen L.

    2012-01-01

    Analysis of galaxies with overlapping images offers a direct way to probe the distribution of dust extinction and its effects on the background light. We present a catalog of 1990 such galaxy pairs selected from the Sloan Digital Sky Survey (SDSS) by volunteers of the Galaxy Zoo project. We highlight subsamples which are particularly useful for retrieving such properties of the dust distribution as UV extinction, the extent perpendicular to the disk plane, and extinction in the inner parts of...

  7. Scleral lenses in the management of keratoconus.

    Science.gov (United States)

    Schornack, Muriel M; Patel, Sanjay V

    2010-01-01

    To describe the use of Jupiter scleral lenses (Medlens Innovations, Front Royal, VA; and Essilor Contact Lenses, Inc., Dallas, TX) in the management of keratoconus. We performed a single-center retrospective chart review of our initial 32 patients with keratoconus evaluated for scleral lens wear. All patients were referred for scleral lens evaluation after exhausting other nonsurgical options for visual correction. Diagnostic lenses were used in the initial fitting process. If adequate fit could not be achieved with standard lenses, custom lenses were designed in consultation with the manufacturers' specialists. The following measures were evaluated for each patient: ability to tolerate and handle lenses, visual acuity with scleral lenses, number of lenses, and visits needed to complete the fitting process. Fifty-two eyes of 32 patients were evaluated for scleral lens wear. Of these, 12 patients (20 eyes) decided not to pursue scleral lens wear after initial evaluation. One patient (2 eyes) abandoned the fitting process after cataract surgery. The remaining 19 patients (30 eyes) were fit successfully. The average number of lenses ordered per eye was 1.5. The fitting process required an average of 2.8 visits. Standard lenses were prescribed for 23 eyes, and custom designs were needed for 7 eyes. Median best-corrected visual acuity improved from 20/40 (mean, 20/76) before scleral lens fitting to 20/20 (mean, 20/30) after fitting. Follow-up ranged from 3 to 32 months. Jupiter scleral lenses provide acceptable visual acuity and comfort in patients with keratoconus. The availability of diagnostic lenses facilitates the fitting process.

  8. The SAMI Galaxy Survey: first 1000 galaxies

    Science.gov (United States)

    Allen, J. T.

    2015-02-01

    The Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey is an ongoing project to obtain integral field spectroscopic observations of ~3400 galaxies by mid-2016. Including the pilot survey, a total of ~1000 galaxies have been observed to date, making the SAMI Galaxy Survey the largest of its kind in existence. This unique dataset allows a wide range of investigations into different aspects of galaxy evolution. The first public data from the SAMI Galaxy Survey, consisting of 107 galaxies drawn from the full sample, has now been released. By giving early access to SAMI data for the entire research community, we aim to stimulate research across a broad range of topics in galaxy evolution. As the sample continues to grow, the survey will open up a new and unique parameter space for galaxy evolution studies.

  9. Glimpse: Sparsity based weak lensing mass-mapping tool

    Science.gov (United States)

    Lanusse, F.; Starck, J.-L.; Leonard, A.; Pires, S.

    2018-02-01

    Glimpse, also known as Glimpse2D, is a weak lensing mass-mapping tool that relies on a robust sparsity-based regularization scheme to recover high resolution convergence from either gravitational shear alone or from a combination of shear and flexion. Including flexion allows the supplementation of the shear on small scales in order to increase the sensitivity to substructures and the overall resolution of the convergence map. To preserve all available small scale information, Glimpse avoids any binning of the irregularly sampled input shear and flexion fields and treats the mass-mapping problem as a general ill-posed inverse problem, regularized using a multi-scale wavelet sparsity prior. The resulting algorithm incorporates redshift, reduced shear, and reduced flexion measurements for individual galaxies and is made highly efficient by the use of fast Fourier estimators.

  10. Multipolar moments of weak lensing signal around clusters. Weighing filaments in harmonic space

    Science.gov (United States)

    Gouin, C.; Gavazzi, R.; Codis, S.; Pichon, C.; Peirani, S.; Dubois, Y.

    2017-09-01

    Context. Upcoming weak lensing surveys such as Euclid will provide an unprecedented opportunity to quantify the geometry and topology of the cosmic web, in particular in the vicinity of lensing clusters. Aims: Understanding the connectivity of the cosmic web with unbiased mass tracers, such as weak lensing, is of prime importance to probe the underlying cosmology, seek dynamical signatures of dark matter, and quantify environmental effects on galaxy formation. Methods: Mock catalogues of galaxy clusters are extracted from the N-body PLUS simulation. For each cluster, the aperture multipolar moments of the convergence are calculated in two annuli (inside and outside the virial radius). By stacking their modulus, a statistical estimator is built to characterise the angular mass distribution around clusters. The moments are compared to predictions from perturbation theory and spherical collapse. Results: The main weakly chromatic excess of multipolar power on large scales is understood as arising from the contraction of the primordial cosmic web driven by the growing potential well of the cluster. Besides this boost, the quadrupole prevails in the cluster (ellipsoidal) core, while at the outskirts, harmonic distortions are spread on small angular modes, and trace the non-linear sharpening of the filamentary structures. Predictions for the signal amplitude as a function of the cluster-centric distance, mass, and redshift are presented. The prospects of measuring this signal are estimated for current and future lensing data sets. Conclusions: The Euclid mission should provide all the necessary information for studying the cosmic evolution of the connectivity of the cosmic web around lensing clusters using multipolar moments and probing unique signatures of, for example, baryons and warm dark matter.

  11. Stellar-to-halo mass relation of cluster galaxies

    International Nuclear Information System (INIS)

    Niemiec, Anna; Jullo, Eric; Limousin, Marceau; Giocoli, Carlo

    2017-01-01

    In the formation of galaxy groups and clusters, the dark matter haloes containing satellite galaxies are expected to be tidally stripped in gravitational interactions with the host. We use galaxy-galaxy weak lensing to measure the average mass of dark matter haloes of satellite galaxies as a function of projected distance to the centre of the host, since stripping is expected to be greater for satellites closer to the centre of the cluster. We further classify the satellites according to their stellar mass: assuming that the stellar component of the galaxy is less disrupted by tidal stripping, stellar mass can be used as a proxy of the infall mass. We study the stellar to halo mass relation of satellites as a function of the cluster-centric distance to measure tidal stripping. We use the shear catalogues of the DES science veri cation archive, the CFHTLenS and the CFHT Stripe 82 surveys, and we select satellites from the redMaPPer catalogue of clusters. For galaxies located in the outskirts of clusters, we nd a stellar to halo mass relation in good agreement with the theoretical expectations from Moster, Naab & White (2013) for central galaxies. In the centre of the cluster, we nd that this relation is shifted to smaller halo mass for a given stellar mass. We interpret this nding as further evidence for tidal stripping of dark matter haloes in high density environments.

  12. Testing cosmology with galaxy clusters

    DEFF Research Database (Denmark)

    Rapetti Serra, David Angelo

    2011-01-01

    such as • the cosmic microwave background, • galaxies and large-scale structure. For further details about how to contact the organising committee or the workshop secretary, please follow the Organisation link. Please follow this link for the full programme of plenary lectures and parallel sessions. (Note that places...

  13. 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.

  14. Modelling the line-of-sight contribution in substructure lensing

    Science.gov (United States)

    Despali, Giulia; Vegetti, Simona; White, Simon D. M.; Giocoli, Carlo; van den Bosch, Frank C.

    2018-04-01

    We investigate how Einstein rings and magnified arcs are affected by small-mass dark-matter haloes placed along the line of sight to gravitational lens systems. By comparing the gravitational signature of line-of-sight haloes with that of substructures within the lensing galaxy, we derive a mass-redshift relation that allows us to rescale the detection threshold (i.e. lowest detectable mass) for substructures to a detection threshold for line-of-sight haloes at any redshift. We then quantify the line-of-sight contribution to the total number density of low-mass objects that can be detected through strong gravitational lensing. Finally, we assess the degeneracy between substructures and line-of-sight haloes of different mass and redshift to provide a statistical interpretation of current and future detections, with the aim of distinguishing between cold dark matter and warm dark matter. We find that line-of-sight haloes statistically dominate with respect to substructures, by an amount