Evolution of Lyα Forest in Redshift Range 0.5

Indian Academy of Sciences (India)

represents the number of Lyα absorption lines in the interval width of unit redshift (z); when z is equal to zero,. ( dn dz. ) is represented by. ( dn dz. ) 0. , and γ is the evolution index. In general, we are using maximum likelihood estimation to do a statistical research. For 1.7 Lyα forest is very strong when ...

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-03-10

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

A Faraday rotation search for magnetic fields in quasar damped Ly alpha absorption systems

Science.gov (United States)

Oren, Abraham L.; Wolfe, Arthur M.

1995-01-01

We present the results of a Faraday rotation survey of 61 radio-bright QSOs conducted at the National Radio Astronomy Observatory (NRAO) Very Large Array (VLA). The Galactic contribution to the Faraday rotation is estimated and subtracted to determine the extragalactic rotation measure (RRM) for each source. Eleven of these QSOs are known to exhibit damped Ly alpha absorption. The rate of incidence of significant Faraday rotation of these 11 sources is compared to the remaining 50 and is found to be higher at the 99.8% confidence level. However, as this is based upon only two detections of Faraday rotation in the damped Ly alpha sample, the result is only tentative. If the two detections in the damped Ly alpha sample are dug to the absorbing systems, then the inferred rotation measure induced by these systems is roughly 250 rad/sq m. The two detections were for the two lowest redshift absorbers in the sample. We find that a rotation measure of 250 rad/sq m would have gone undetected for any other absorber in the damped Ly alpha sample due to the 1/(1 + 2) squared dilution of the observed RRM with redshift. Thus the data are consistent with, but do not prove, the hypothesis that Faraday rotation is a generic property of damped Ly alpha absorbers. We do not confirm the suggestion that the amplitude of RRMs increases with redshift. Rather, the data are consistent with no redshift evolution. We find that the uncertainty in the estimation of the Galactic rotation measure (GRM) is a more serious problem than previously realized for extra-galactic Faraday rotation studies of QSO absorbers. A careful analysis of current methods for estimating GRM indicate that it can be determined to an accuracy of about 15 - 20 rad/sq m. Previous studies underestimated this uncertainty by more than a factor of 2. Due to this uncertainty, rotation measures such as we suspect are associated with damped Ly alpha absorption systems can only be detected at redshifts less than z approximately

arXiv Neutrino masses and cosmology with Lyman-alpha forest power spectrum

CERN Document Server

Palanque-Delabrouille, Nathalie; Baur, Julien; Magneville, Christophe; Rossi, Graziano; Lesgourgues, Julien; Borde, Arnaud; Burtin, Etienne; LeGoff, Jean-Marc; Rich, James; Viel, Matteo; Weinberg, David

2015-11-06

We present constraints on neutrino masses, the primordial fluctuation spectrum from inflation, and other parameters of the $\\Lambda$CDM model, using the one-dimensional Ly$\\alpha$-forest power spectrum measured by Palanque-Delabrouille et al. (2013) from SDSS-III/BOSS, complemented by Planck 2015 cosmic microwave background (CMB) data and other cosmological probes. This paper improves on the previous analysis by Palanque-Delabrouille et al. (2015) by using a more powerful set of calibrating hydrodynamical simulations that reduces uncertainties associated with resolution and box size, by adopting a more flexible set of nuisance parameters for describing the evolution of the intergalactic medium, by including additional freedom to account for systematic uncertainties, and by using Planck 2015 constraints in place of Planck 2013. Fitting Ly$\\alpha$ data alone leads to cosmological parameters in excellent agreement with the values derived independently from CMB data, except for a weak tension on the scalar index ...

Observation of solar hydrogen Ly-αline with the K-10-12 rocket

International Nuclear Information System (INIS)

Koshio, Takafumi; Masuoka, Toshio; Tono, Ichiro; Watanabe, Norihiko.

1976-01-01

The purpose of the observation is to perform the absolute irradiance measurement of the solar hydrogen Ly-α line (1216 A 0 ) in the exosphere. The solar hydrogen Ly-α line is emitted from the chromosphere, and contributes to the ionization in the lower ionosphere. The ionization chamber was used for the detection of the solar hydrogen Ly-α line. The K-10-9 rocket was launched on Jan. 18, 1976. The irradiance of the solar hydrogen Ly-α line was measured in the exosphere, and the height distribution of O 2 density was studied on the basis of the absorbancy of the HLy-α line. The result was in good agreement with the previously observed results. (Yoshimori, M.)

A New Method to Measure the Post-reionization Ionizing Background from the Joint Distribution of Lyα and Lyβ Forest Transmission

Science.gov (United States)

Davies, Frederick B.; Hennawi, Joseph F.; Eilers, Anna-Christina; Lukić, Zarija

2018-03-01

The amplitude of the ionizing background that pervades the intergalactic medium (IGM) at the end of the epoch of reionization provides a valuable constraint on the emissivity of the sources that reionized the universe. While measurements of the ionizing background at lower redshifts rely on a simulation-calibrated mapping between the photoionization rate and the mean transmission of the Lyα forest, at z ≳ 6 the IGM becomes increasingly opaque and transmission arises solely in narrow spikes separated by saturated Gunn–Peterson troughs. In this regime, the traditional approach of measuring the average transmission over large ∼50 Mpc/h regions is less sensitive and suboptimal. In addition, the five times smaller oscillator strength of the Lyβ transition implies that the Lyβ forest is considerably more transparent at z ≳ 6, even in the presence of contamination by foreground z ∼ 5 Lyα forest absorption. In this work we present a novel statistical approach to analyze the joint distribution of transmission spikes in the cospatial z ∼ 6 Lyα and Lyβ forests. Our method relies on approximate Bayesian computation (ABC), which circumvents the necessity of computing the intractable likelihood function describing the highly correlated Lyα and Lyβ transmission. We apply ABC to mock data generated from a large-volume hydrodynamical simulation combined with a state-of-the-art model of ionizing background fluctuations in the post-reionization IGM and show that it is sensitive to higher IGM neutral hydrogen fractions than previous techniques. As a proof of concept, we apply this methodology to a real spectrum of a z = 6.54 quasar and measure the ionizing background from 5.4 ≤ z ≤ 6.4 along this sightline with ∼0.2 dex statistical uncertainties. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the

Indication of the Hanle Effect by Comparing the Scattering Polarization Observed by CLASP in the Ly α and Si iii 120.65 nm Lines

Energy Technology Data Exchange (ETDEWEB)

Ishikawa, R.; Kubo, M.; Kano, R.; Narukage, N.; Bando, T.; Katsukawa, Y.; Giono, G.; Suematsu, Y.; Hara, H. [National Astronomical Observatory of Japan, National Institutes of Natural Science, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Bueno, J. Trujillo [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Uitenbroek, H. [National Solar Observatory, 3665 Discovery Drive, Boulder, CO 80303 (United States); Tsuneta, S.; Ishikawa, S.; Shimizu, T.; Sakao, T. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210 (Japan); Goto, M. [National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu 509-5292 (Japan); Winebarger, A.; Kobayashi, K. [NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States); Cirtain, J. [University of Virginia, Department of Astronomy, 530 McCormick Road, Charlottesville, VA 22904 (United States); Champey, P. [University of Alabama in Huntsville, 301 Sparkman Drive, Huntsville, AL 35899 (United States); and others

2017-05-20

The Chromospheric Lyman-Alpha Spectro-Polarimeter is a sounding rocket experiment that has provided the first successful measurement of the linear polarization produced by scattering processes in the hydrogen Ly α line (121.57 nm) radiation of the solar disk. In this paper, we report that the Si iii line at 120.65 nm also shows scattering polarization and we compare the scattering polarization signals observed in the Ly α and Si iii lines in order to search for observational signatures of the Hanle effect. We focus on four selected bright structures and investigate how the U / I spatial variations vary between the Ly α wing, the Ly α core, and the Si iii line as a function of the total unsigned photospheric magnetic flux estimated from Solar Dynamics Observatory /Helioseismic and Magnetic Imager observations. In an internetwork region, the Ly α core shows an antisymmetric spatial variation across the selected bright structure, but it does not show it in other more magnetized regions. In the Si iii line, the spatial variation of U / I deviates from the above-mentioned antisymmetric shape as the total unsigned photospheric magnetic flux increases. A plausible explanation of this difference is the operation of the Hanle effect. We argue that diagnostic techniques based on the scattering polarization observed simultaneously in two spectral lines with very different sensitivities to the Hanle effect, like Ly α and Si iii, are of great potential interest for exploring the magnetism of the upper solar chromosphere and transition region.

PHYSICAL PROPERTIES OF Ly{alpha} EMITTERS AT z {approx} 0.3 FROM UV-TO-FIR MEASUREMENTS

Energy Technology Data Exchange (ETDEWEB)

Oteo, I.; Bongiovanni, A.; Perez Garcia, A. M.; Cepa, J.; Pintos-Castro, I. [Instituto de Astrofisica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Ederoclite, A. [Centro de Estudios de Fisica del Cosmos de Aragon, Plaza San Juan 1, Planta 2, Teruel, 44001 (Spain); Sanchez-Portal, M.; Altieri, B. [Herschel Science Centre (ESAC), Villafranca del Castillo (Spain); Perez-Martinez, R. [XMM/Newton Science Operations Centre (ESAC), Villafranca del Castillo (Spain); Lutz, D.; Berta, S.; Foerster Schreiber, N.; Genzel, R.; Magnelli, B. [Max-Planck-Institut fuer Extraterrestrische Physik (MPE), Postfach 1312, 85741 Garching (Germany); Andreani, P. [ESO, Karl-Schwarzchild-Str. 2, D-85748 Garching (Germany); Aussel, H.; Daddi, E.; Elbaz, D.; Le Floc' h, E. [Commissariat a l' Energie Atomique (CEA-SAp) Saclay (France); Cimatti, A. [Dipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, 40127 Bologna (Italy); and others

2012-06-01

The analysis of the physical properties of low-redshift Ly{alpha} emitters (LAEs) can provide clues in the study of their high-redshift analogs. At z {approx} 0.3, LAEs are bright enough to be detected over almost the entire electromagnetic spectrum and it is possible to carry out a more precise and complete study than at higher redshifts. In this work, we examine the UV and IR emission, dust attenuation, star formation rate (SFR), and morphology of a sample of 23 GALEX-discovered star-forming LAEs at z {approx} 0.3 with direct UV (GALEX), optical (ACS), and FIR (PACS and MIPS) data. Using the same UV and IR limiting luminosities, we find that LAEs at z {approx} 0.3 tend to be less dusty, have slightly higher total SFRs, have bluer UV continuum slopes, and are much smaller than other galaxies that do not exhibit Ly{alpha} emission in their spectrum (non-LAEs). These results suggest that at z {approx} 0.3, Ly{alpha} photons tend to escape from small galaxies with low dust attenuation. Regarding their morphology, LAEs belong to Irr/merger classes, unlike non-LAEs. Size and morphology represent the most noticeable difference between LAEs and non-LAEs at z {approx} 0.3. Furthermore, the comparison of our results with those obtained at higher redshifts indicates either that the Ly{alpha} technique picks up different kind of galaxies at different redshifts or that the physical properties of LAEs are evolving with redshift.

The Lyman alpha reference sample

DEFF Research Database (Denmark)

Hayes, M.; Östlin, G.; Schaerer, D.

2013-01-01

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

Discovery of Scattering Polarization in the Hydrogen Ly α Line of the Solar Disk Radiation

International Nuclear Information System (INIS)

Kano, R.; Narukage, N.; Ishikawa, R.; Bando, T.; Katsukawa, Y.; Kubo, M.; Giono, G.; Hara, H.; Suematsu, Y.; Bueno, J. Trujillo; Winebarger, A.; Kobayashi, K.; Auchère, F.; Ishikawa, S.; Shimizu, T.; Sakao, T.; Tsuneta, S.; Ichimoto, K.; Goto, M.; Belluzzi, L.

2017-01-01

There is a thin transition region (TR) in the solar atmosphere where the temperature rises from 10,000 K in the chromosphere to millions of degrees in the corona. Little is known about the mechanisms that dominate this enigmatic region other than the magnetic field plays a key role. The magnetism of the TR can only be detected by polarimetric measurements of a few ultraviolet (UV) spectral lines, the Ly α line of neutral hydrogen at 121.6 nm (the strongest line of the solar UV spectrum) being of particular interest given its sensitivity to the Hanle effect (the magnetic-field-induced modification of the scattering line polarization). We report the discovery of linear polarization produced by scattering processes in the Ly α line, obtained with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) rocket experiment. The Stokes profiles observed by CLASP in quiet regions of the solar disk show that the Q / I and U / I linear polarization signals are of the order of 0.1% in the line core and up to a few percent in the nearby wings, and that both have conspicuous spatial variations with scales of ∼10 arcsec. These observations help constrain theoretical models of the chromosphere–corona TR and extrapolations of the magnetic field from photospheric magnetograms. In fact, the observed spatial variation from disk to limb of polarization at the line core and wings already challenge the predictions from three-dimensional magnetohydrodynamical models of the upper solar chromosphere.

Discovery of Scattering Polarization in the Hydrogen Ly α Line of the Solar Disk Radiation

Energy Technology Data Exchange (ETDEWEB)

Kano, R.; Narukage, N.; Ishikawa, R.; Bando, T.; Katsukawa, Y.; Kubo, M.; Giono, G.; Hara, H.; Suematsu, Y. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Bueno, J. Trujillo [Instituto de Astrofísica de Canarias, La Laguna, Tenerife, E-38205 (Spain); Winebarger, A.; Kobayashi, K. [Marshall Space Flight Center, National Aeronautics and Space Administration (NASA), Huntsville, AL 35812 (United States); Auchère, F. [Institut d’Astrophysique Spatiale, Université Paris Sud, Batiment 121, F-91405 Orsay (France); Ishikawa, S.; Shimizu, T.; Sakao, T.; Tsuneta, S. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210 (Japan); Ichimoto, K. [Hida Observatory, Kyoto University, Takayama, Gifu 506-1314 (Japan); Goto, M. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Belluzzi, L., E-mail: ryouhei.kano@nao.ac.jp [Istituto Ricerche Solari Locarno, CH-6605 Locarno Monti (Switzerland); and others

2017-04-10

There is a thin transition region (TR) in the solar atmosphere where the temperature rises from 10,000 K in the chromosphere to millions of degrees in the corona. Little is known about the mechanisms that dominate this enigmatic region other than the magnetic field plays a key role. The magnetism of the TR can only be detected by polarimetric measurements of a few ultraviolet (UV) spectral lines, the Ly α line of neutral hydrogen at 121.6 nm (the strongest line of the solar UV spectrum) being of particular interest given its sensitivity to the Hanle effect (the magnetic-field-induced modification of the scattering line polarization). We report the discovery of linear polarization produced by scattering processes in the Ly α line, obtained with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) rocket experiment. The Stokes profiles observed by CLASP in quiet regions of the solar disk show that the Q / I and U / I linear polarization signals are of the order of 0.1% in the line core and up to a few percent in the nearby wings, and that both have conspicuous spatial variations with scales of ∼10 arcsec. These observations help constrain theoretical models of the chromosphere–corona TR and extrapolations of the magnetic field from photospheric magnetograms. In fact, the observed spatial variation from disk to limb of polarization at the line core and wings already challenge the predictions from three-dimensional magnetohydrodynamical models of the upper solar chromosphere.

THE LINE POLARIZATION WITHIN A GIANT Lyα NEBULA

International Nuclear Information System (INIS)

Prescott, Moire K. M.; Smith, Paul S.; Schmidt, Gary D.; Dey, Arjun

2011-01-01

Recent theoretical work has suggested that Lyα nebulae could be substantially polarized in the Lyα emission line, depending on the geometry, kinematics, and powering mechanism at work. Polarization observations can therefore provide a useful constraint on the source of ionization in these systems. In this Letter, we present the first Lyα polarization measurements for a giant Lyα nebula at z∼ 2.656. We do not detect any significant linear polarization of the Lyα emission: P Lyα = 2.6% ± 2.8% (corrected for statistical bias) within a single large aperture. The current data also do not show evidence for the radial polarization gradient predicted by some theoretical models. These results rule out singly scattered Lyα (e.g., from the nearby active galactic nucleus, AGN) and may be inconsistent with some models of backscattering in a spherical outflow. However, the effects of seeing, diminished signal-to-noise ratio, and angle averaging within radial bins make it difficult to put strong constraints on the radial polarization profile. The current constraints may be consistent with higher density outflow models, spherically symmetric infall models, photoionization by star formation within the nebula or the nearby AGN, resonant scattering, or non-spherically symmetric cold accretion (i.e., along filaments). Higher signal-to-noise ratio data probing to higher spatial resolution will allow us to harness the full diagnostic power of polarization observations in distinguishing between theoretical models of giant Lyα nebulae.

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

International Nuclear Information System (INIS)

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

2013-01-01

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

THE Lyα LINE PROFILES OF ULTRALUMINOUS INFRARED GALAXIES: FAST WINDS AND LYMAN CONTINUUM LEAKAGE

Energy Technology Data Exchange (ETDEWEB)

Martin, Crystal L.; Wong, Joseph [Department of Physics, University of California, Santa Barbara, CA, 93106 (United States); Dijkstra, Mark [Institute of Theoretical Astrophysics, University of Oslo, Postboks 1029, 0858 Oslo (Norway); Henry, Alaina [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Soto, Kurt T. [Institute for Astronomy, Department of Physics, ETH Zurich, CH-8093 Zurich (Switzerland); Danforth, Charles W., E-mail: cmartin@physics.ucsb.edu [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO, 80309 (United States)

2015-04-10

We present new Hubble Space Telescope Cosmic Origins Spectrograph far-ultraviolet (far-UV) spectroscopy and Keck Echellete optical spectroscopy of 11 ultraluminous infrared galaxies (ULIRGs), a rare population of local galaxies experiencing massive gas inflows, extreme starbursts, and prominent outflows. We detect Lyα emission from eight ULIRGs and the companion to IRAS09583+4714. In contrast to the P Cygni profiles often seen in galaxy spectra, the Lyα profiles exhibit prominent, blueshifted emission out to Doppler shifts exceeding −1000 km s{sup −1} in three H ii-dominated and two AGN-dominated ULIRGs. To better understand the role of resonance scattering in shaping the Lyα line profiles, we directly compare them to non-resonant emission lines in optical spectra. We find that the line wings are already present in the intrinsic nebular spectra, and scattering merely enhances the wings relative to the line core. The Lyα attenuation (as measured in the COS aperture) ranges from that of the far-UV continuum to over 100 times more. A simple radiative transfer model suggests the Lyα photons escape through cavities which have low column densities of neutral hydrogen and become optically thin to the Lyman continuum in the most advanced mergers. We show that the properties of the highly blueshifted line wings on the Lyα and optical emission-line profiles are consistent with emission from clumps of gas condensing out of a fast, hot wind. The luminosity of the Lyα emission increases nonlinearly with the ULIRG bolometric luminosity and represents about 0.1–1% of the radiative cooling from the hot winds in the H ii-dominated ULIRGs.

Noise estimates for measurements of weak lensing from the Ly α forest

Science.gov (United States)

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

2018-06-01

Lensing changes the apparent separation between pixels in the Ly 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 Ly 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 Ly α forest lensing measurements from the DESI and WEAVE surveys should yield the mass fluctuation amplitude with a statistical error of ˜3 per cent, eBOSS ˜6 per cent. and the proposed MSE survey less than 1 per cent. 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.

GAS MOTION STUDY OF Lyα EMITTERS AT z ∼ 2 USING FUV AND OPTICAL SPECTRAL LINES ,

International Nuclear Information System (INIS)

Hashimoto, Takuya; Shimasaku, Kazuhiro; Nakajima, Kimihiko; Ouchi, Masami; Ono, Yoshiaki; Rauch, Michael; Janice Lee; Okamura, Sadanori

2013-01-01

We present the results of Magellan/MMIRS and Keck/NIRSPEC spectroscopy for five Lyα emitters (LAEs) at z ≅ 2.2 for which high-resolution FUV spectra from Magellan/MagE are available. We detect nebular emission lines including Hα on the individual basis and low-ionization interstellar (LIS) absorption lines in a stacked FUV spectrum, and measure average offset velocities of the Lyα line, Δv Lyα , and LIS absorption lines, Δv abs , with respect to the systemic velocity defined by the nebular lines. For a sample of eight z ∼ 2-3 LAEs without active galactic nucleus from our study and the literature, we obtain Δv Lyα = 175 ± 35 km s –1 , which is significantly smaller than that of Lyman-break Galaxies (LBGs), Δv Lyα ≅ 400 km s –1 . The stacked FUV spectrum gives Δv abs = –179 ± 73 km s –1 , comparable to that of LBGs. These positive Δv Lyα and negative Δv abs suggest that LAEs also have outflows. In contrast to LBGs, however, the LAEs' Δv Lyα is as small as |Δv abs |, suggesting low neutral hydrogen column densities. Such a low column density with a small number of resonant scattering may cause the observed strong Lyα emission of LAEs. We find an anti-correlation between Lyα equivalent width (EW) and Δv Lyα in a compilation of LAE and LBG samples. Although its physical origin is not clear, this anti-correlation result appears to challenge the hypothesis that a strong outflow, by means of a reduced number of resonant scattering, produces a large EW. If LAEs at z > 6 have similarly small Δv Lyα values, constraints on the reionization history derived from the Lyα transmissivity may need to be revised.

A quadruple quasar coincident with a giant Ly-alpha nebula and a protocluster at z=2

Science.gov (United States)

Vignali, Cristian

2016-09-01

We propose to observe the only known quadruple AGN system in the Universe, embedded in a giant Ly-alpha nebula at z 2. These active nuclei and the large number of Ly-alpha emitting galaxies at the same redshift are clear indications that this is one of the most overdense protoclusters known z 2. We request a 140 ks Chandra exposure to (a) define the basic X-ray properties of all the AGN and then their bolometric luminosities and Eddington ratios, and compare these with those of "isolated" quasars at similar redshifts/luminosities; (b) detect the hot gas emission in the protocluster. Chandra is unique for this investigation: the close (few arcsec) distance of some of the AGN needs high spatial resolution, and the extended emission requires low background contribution.

The non-linear power spectrum of the Lyman alpha forest

International Nuclear Information System (INIS)

Arinyo-i-Prats, Andreu; Miralda-Escudé, Jordi; Viel, Matteo; Cen, Renyue

2015-01-01

The Lyman alpha forest power spectrum has been measured on large scales by the BOSS survey in SDSS-III at z∼ 2.3, has been shown to agree well with linear theory predictions, and has provided the first measurement of Baryon Acoustic Oscillations at this redshift. However, the power at small scales, affected by non-linearities, has not been well examined so far. We present results from a variety of hydrodynamic simulations to predict the redshift space non-linear power spectrum of the Lyα transmission for several models, testing the dependence on resolution and box size. A new fitting formula is introduced to facilitate the comparison of our simulation results with observations and other simulations. The non-linear power spectrum has a generic shape determined by a transition scale from linear to non-linear anisotropy, and a Jeans scale below which the power drops rapidly. In addition, we predict the two linear bias factors of the Lyα forest and provide a better physical interpretation of their values and redshift evolution. The dependence of these bias factors and the non-linear power on the amplitude and slope of the primordial fluctuations power spectrum, the temperature-density relation of the intergalactic medium, and the mean Lyα transmission, as well as the redshift evolution, is investigated and discussed in detail. A preliminary comparison to the observations shows that the predicted redshift distortion parameter is in good agreement with the recent determination of Blomqvist et al., but the density bias factor is lower than observed. We make all our results publicly available in the form of tables of the non-linear power spectrum that is directly obtained from all our simulations, and parameters of our fitting formula

A Luminous Lyα-emitting Galaxy at Redshift z = 6.535: Discovery and Spectroscopic Confirmation

Science.gov (United States)

Rhoads, James E.; Xu, Chun; Dawson, Steve; Dey, Arjun; Malhotra, Sangeeta; Wang, JunXian; Jannuzi, Buell T.; Spinrad, Hyron; Stern, Daniel

2004-08-01

We present a redshift z=6.535 galaxy discovered by its Lyα emission in a 9180 Å narrowband image from the Large Area Lyman Alpha survey. The Lyα line luminosity (1.1×1043 ergs s-1) is among the largest known for star-forming galaxies at z~6.5. The line shows the distinct asymmetry that is characteristic of high-redshift Lyα. The 2 σ lower bound on the observer-frame equivalent width is greater than 530 Å. This is hard to reconcile with a neutral intergalactic medium (IGM) unless the Lyα line is intrinsically strong and is emitted from its host galaxy with an intrinsic Doppler shift of several hundred km s-1. If the IGM is ionized, it corresponds to a rest-frame equivalent width greater than 40 Å after correcting for Lyα forest absorption. We also present a complete spectroscopic follow-up of the remaining candidates with line flux greater than 2×10-17 ergs cm-2 s-1 in our 1200 arcmin2 narrowband image. These include another galaxy with a strong emission line at 9136 Å and no detected continuum flux, which, however, is most likely an [O III] λ5007 source at z=0.824, on the basis of a weak detection of the [O III] λ4959 line. The data presented in this paper were obtained at the Kitt Peak National Observatory, the Gemini Observatory, and the W. M. Keck Observatory. Kitt Peak National Observatory, National Optical Astronomy Observatory, is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under cooperative agreement with the National Science Foundation (NSF). The Gemini Observatory is operated by AURA under a cooperative agreement with the NSF on behalf of the Gemini partnership: the NSF (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council, CNPq (Brazil), and CONICET (Argentina). The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the

Lyα Profile, Dust, and Prediction of Lyα Escape Fraction in Green Pea Galaxies

Science.gov (United States)

Yang, Huan; Malhotra, Sangeeta; Gronke, Max; Rhoads, James E.; Leitherer, Claus; Wofford, Aida; Jiang, Tianxing; Dijkstra, Mark; Tilvi, V.; Wang, Junxian

2017-08-01

We studied Lyman-α (Lyα) escape in a statistical sample of 43 Green Peas with HST/COS Lyα spectra. Green Peas are nearby star-forming galaxies with strong [O III]λ5007 emission lines. Our sample is four times larger than the previous sample and covers a much more complete range of Green Pea properties. We found that about two-thirds of Green Peas are strong Lyα line emitters with rest-frame Lyα equivalent width > 20 \\mathringA . The Lyα profiles of Green Peas are diverse. The Lyα escape fraction, defined as the ratio of observed Lyα flux to intrinsic Lyα flux, shows anti-correlations with a few Lyα kinematic features—both the blue peak and red peak velocities, the peak separations, and the FWHM of the red portion of the Lyα profile. Using properties measured from Sloan Digital Sky Survey optical spectra, we found many correlations—the Lyα escape fraction generally increases at lower dust reddening, lower metallicity, lower stellar mass, and higher [O III]/[O II] ratio. We fit their Lyα profiles with the H I shell radiative transfer model and found that the Lyα escape fraction is anti-correlated with the best-fit N H I . Finally, we fit an empirical linear relation to predict {f}{esc}{Lyα } from the dust extinction and Lyα red peak velocity. The standard deviation of this relation is about 0.3 dex. This relation can be used to isolate the effect of intergalactic medium (IGM) scatterings from Lyα escape and to probe the IGM optical depth along the line of sight of each z> 7 Lyα emission-line galaxy in the James Webb Space Telescope era.

The z = 0.8596 damped Ly-alpha absorbing galaxy toward PKS 0454+039

Science.gov (United States)

Steidel, Charles C.; Bowen, David V.; Blades, J. Chris; Dickenson, Mark

1995-01-01

We present Hubble Space Telescope (HST) and ground-based data on the Z(sub abs) = 0.8596 metal-line absorption system along the line of sight to PKS 0454+0356. The system is a moderate-redshift damped Ly-alpha system, with N(H I) = (5.7 +/- 0.3) x 10(exp 20)/sq cm as measured from the Faint Object Spectrograph (FOS) spectrum. We also present ground-based images which we use to identify the galaxy which most probably gives rise to the damped system; the most likely candidate is relatively underluminous by QSO absorber standards M(sub B) approximately -19.0 for A(sub 0) = 0.5 and H(sub 0) = 50 km/s/Mpc) and lies approximately 8.5/h kpc in projection from the QSO sight line. Ground-based measurements of Zn II, Cr II, and Fe II absorption lines from this system allow us to infer abundances of (Zn/H) = -1.1, (Cr/H) = -1.2, and (Fe/H) = -1.2 indicating overall metallicity similar to damped systems at z is greater than 2, and that the depletion of Cr and Fe onto dust grains may be even less important than in many of the high-redshift systems of comparable metallicity. Limits previously placed on the 21 cm optical depth in the z = 0.8596 system, together with our new N(H I) measurement, suggest a very high spin temperature for the H I, T(sub s) is greater than 580 K.

PROBING THE EPOCH OF REIONIZATION WITH THE Lyα FOREST AT z ∼ 4-5

International Nuclear Information System (INIS)

Cen Renyue; McDonald, Patrick; Trac, Hy; Loeb, Abraham

2009-01-01

The inhomogeneous cosmological reionization process leaves tangible imprints in the intergalactic medium (IGM) down to z ∼ 4-5. The Lyα forest flux power spectrum provides a potentially powerful probe of the epoch of reionization. With the existing Sloan Digital Sky Survey I/II quasar sample, we show that two cosmological reionization scenarios, one completing reionization at z = 6 and the other at z = 9, can be distinguished at ∼7σ level by utilizing Lyα forest absorption spectra at z = 3.9-4.1 in the absence of other physical processes that may also affect the Lyα flux power spectrum. The difference may not be distinguishable at such high significance after marginalization over other effects, but, in any case, one will need to consider this effect in order to correctly interpret the power spectrum in this redshift range. The redshift range z = 4-5 may provide the best window because there are still enough transmitted flux and quasars to measure precise statistics of the flux fluctuations, and the IGM still retains a significant amount of memory of reionization.

On the inversion of the scattering polarization and the Hanle effect signals in the hydrogen Lyα line

Energy Technology Data Exchange (ETDEWEB)

Ishikawa, R. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Asensio Ramos, A.; Manso Sainz, R.; Trujillo Bueno, J. [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain); Belluzzi, L. [Istituto Ricerche Solari Locarno (IRSOL), via Patocchi, 6605 Locarno Monti (Switzerland); Štěpán, J. [Astronomical Institute of the Academy of Sciences, Fričova 298, 251 65 Ondřejov (Czech Republic); Goto, M. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan); Tsuneta, S., E-mail: ryoko.ishikawa@nao.ac.jp [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210 (Japan)

2014-06-01

Magnetic field measurements in the upper chromosphere and above, where the gas-to-magnetic pressure ratio β is lower than unity, are essential for understanding the thermal structure and dynamical activity of the solar atmosphere. Recent developments in the theory and numerical modeling of polarization in spectral lines have suggested that information on the magnetic field of the chromosphere-corona transition region could be obtained by measuring the linear polarization of the solar disk radiation at the core of the hydrogen Lyα line at 121.6 nm, which is produced by scattering processes and the Hanle effect. The Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) sounding rocket experiment aims to measure the intensity (Stokes I) and the linear polarization profiles (Q/I and U/I) of the hydrogen Lyα line. In this paper, we clarify the information that the Hanle effect can provide by applying a Stokes inversion technique based on a database search. The database contains all theoretical Q/I and U/I profiles calculated in a one-dimensional semi-empirical model of the solar atmosphere for all possible values of the strength, inclination, and azimuth of the magnetic field vector, though this atmospheric region is highly inhomogeneous and dynamic. We focus on understanding the sensitivity of the inversion results to the noise and spectral resolution of the synthetic observations as well as the ambiguities and limitation inherent to the Hanle effect when only the hydrogen Lyα is used. We conclude that spectropolarimetric observations with CLASP can indeed be a suitable diagnostic tool for probing the magnetism of the transition region, especially when complemented with information on the magnetic field azimuth that can be obtained from other instruments.

THE LYMAN ALPHA REFERENCE SAMPLE. V. THE IMPACT OF NEUTRAL ISM KINEMATICS AND GEOMETRY ON Lyα ESCAPE

International Nuclear Information System (INIS)

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

2015-01-01

We present high-resolution far-UV spectroscopy of the 14 galaxies of the Lyα Reference Sample; a sample of strongly star-forming galaxies at low redshifts (0.028 < z < 0.18). We compare the derived properties to global properties derived from multi-band imaging and 21 cm H i interferometry and single-dish observations, as well as archival optical SDSS spectra. Besides the Lyα line, the spectra contain a number of metal absorption features allowing us to probe the kinematics of the neutral ISM and evaluate the optical depth and and covering fraction of the neutral medium as a function of line of sight velocity. Furthermore, we show how this, in combination with the precise determination of systemic velocity and good Lyα spectra, can be used to distinguish a model in which separate clumps together fully cover the background source, from the “picket fence” model named by Heckman et al. We find that no one single effect dominates in governing Lyα radiative transfer and escape. Lyα escape in our sample coincides with a maximum velocity-binned covering fraction of ≲0.9 and bulk outflow velocities of ≳50 km s −1 , although a number of galaxies show these characteristics and yet little or no Lyα escape. We find that Lyα peak velocities, where available, are not consistent with a strong backscattered component, but rather with a simpler model of an intrinsic emission line overlaid by a blueshifted absorption profile from the outflowing wind. Finally, we find a strong anticorrelation between Hα equivalent width and maximum velocity-binned covering factor, and propose a heuristic explanatory model

THE LYMAN ALPHA REFERENCE SAMPLE. V. THE IMPACT OF NEUTRAL ISM KINEMATICS AND GEOMETRY ON Lyα ESCAPE

Energy Technology Data Exchange (ETDEWEB)

Rivera-Thorsen, Thøger E.; Hayes, Matthew; Östlin, Göran; Duval, Florent; Sandberg, Andreas; Guaita, Lucia; Adamo, Angela [Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden); Orlitová, Ivana [Astronomical Institute, Academy of Sciences of the Czech Republic, Boční II, CZ-14131 Prague (Czech Republic); Verhamme, Anne; Schaerer, Daniel [Geneva Observatory, University of Geneva, 51 Chemin des Maillettes, CH-1290 Versoix (Switzerland); Mas-Hesse, J. Miguel [Centro de Astrobiología (CSIC–INTA), Departamento de Astrofísica, P.O. Box 78, E-28691 Villanueva de la Cañada (Spain); Cannon, John M. [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Otí-Floranes, Héctor [Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 106, B. C. 22800 Ensenada (Mexico); Atek, Hakim [Laboratoire d’Astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire, CH-1290 Sauverny (Switzerland); Herenz, E. Christian [Leibniz-Institut für Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Kunth, Daniel, E-mail: trive@astro.su.se [Institut d’Astrophysique de Paris, UMR 7095 CNRS and UPMC, 98 bis Bd Arago, F-75014 Paris (France); and others

2015-05-20

We present high-resolution far-UV spectroscopy of the 14 galaxies of the Lyα Reference Sample; a sample of strongly star-forming galaxies at low redshifts (0.028 < z < 0.18). We compare the derived properties to global properties derived from multi-band imaging and 21 cm H i interferometry and single-dish observations, as well as archival optical SDSS spectra. Besides the Lyα line, the spectra contain a number of metal absorption features allowing us to probe the kinematics of the neutral ISM and evaluate the optical depth and and covering fraction of the neutral medium as a function of line of sight velocity. Furthermore, we show how this, in combination with the precise determination of systemic velocity and good Lyα spectra, can be used to distinguish a model in which separate clumps together fully cover the background source, from the “picket fence” model named by Heckman et al. We find that no one single effect dominates in governing Lyα radiative transfer and escape. Lyα escape in our sample coincides with a maximum velocity-binned covering fraction of ≲0.9 and bulk outflow velocities of ≳50 km s{sup −1}, although a number of galaxies show these characteristics and yet little or no Lyα escape. We find that Lyα peak velocities, where available, are not consistent with a strong backscattered component, but rather with a simpler model of an intrinsic emission line overlaid by a blueshifted absorption profile from the outflowing wind. Finally, we find a strong anticorrelation between Hα equivalent width and maximum velocity-binned covering factor, and propose a heuristic explanatory model.

Minihalo Model for the Low-Redshift Lyman alpha Absorbers Revisited

Directory of Open Access Journals (Sweden)

Lalović, A.

2008-06-01

Full Text Available We reconsider the basic properties of the classical minihalo model of Rees and Milgrom in light of the new work, both observational (on "dark galaxies" and masses of baryonic haloes and theoretical (on the cosmological mass function and the history of star formation. In particular, we show that more detailed models of ionized gas in haloes of dark matter following isothermal and Navarro-Frenk-White density profile can effectively reproduce particular aspects of the observed column density distribution function in a heterogeneous sample of low-and intermediate-redshift Ly$alpha$ forest absorption lines.

A SEARCH FOR OXYGEN IN THE LOW-DENSITY Lyα FOREST USING THE SLOAN DIGITAL SKY SURVEY

International Nuclear Information System (INIS)

Pieri, Matthew M.; Frank, Stephan; Mathur, Smita; Weinberg, David H.; York, Donald G.; Oppenheimer, Benjamin D.

2010-01-01

We use 2167 Sloan Digital Sky Survey quasar spectra to search for low-density oxygen in the intergalactic medium (IGM). Oxygen absorption is detected on a pixel-by-pixel basis by its correlation with Lyα forest absorption. We have developed a novel locally calibrated pixel (LCP) search method that uses adjacent regions of the spectrum to calibrate interlopers and spectral artifacts, which would otherwise limit the measurement of O VI absorption. Despite the challenges presented by searching for weak O VI within the Lyα forest in spectra of moderate resolution and signal-to-noise, we find a highly significant detection of absorption by oxygen at 2.7 2 = 80 for nine data points). We interpret our results using synthetic spectra generated from a log-normal density field assuming a mixed quasar-galaxy photoionizing background and that it dominates the ionization fraction of detected O VI. The LCP search data can be fit by a constant metallicity model with [O/H] = -2.15 +0.07 -0.09 but also by models in which low-density regions are unenriched and higher density regions have a higher metallicity. The density-dependent enrichment model by Aguirre et al. is also an acceptable fit. All our successful models have similar mass-weighted oxygen abundance, corresponding to [(O/H) MW ] = -2.45 ± 0.06. This result can be used to find the cosmic oxygen density in the Lyα forest, Ω Oxy,IGM = 1.4(±0.2) x 10 -6 ∼ 3 x 10 -4 Ω b . This is the tightest constraint on the mass-weighted mean oxygen abundance and the cosmic oxygen density in the Lyα forest to date and indicates that it contains ∼16% of the total expected metal production by star formation up to z = 3.

The large-scale cross-correlation of Damped Lyman alpha systems with the Lyman alpha forest: first measurements from BOSS

Energy Technology Data Exchange (ETDEWEB)

Font-Ribera, Andreu [Institute of Theoretical Physics, University of Zurich, 8057 Zurich (Switzerland); Miralda-Escudé, Jordi [Institució Catalana de Recerca i Estudis Avançats, Barcelona, Catalonia (Spain); Arnau, Eduard [Institut de Ciències del Cosmos (IEEC/UB), Barcelona, Catalonia (Spain); Carithers, Bill; Ross, Nicholas P.; White, Martin [Lawrence Berkeley National Laboratory, University of California Berkeley, Berkeley, California 94720 (United States); Lee, Khee-Gan [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany); Noterdaeme, Pasquier; Pâris, Isabelle; Petitjean, Patrick; Rollinde, Emmanuel [Institut d' Astrophysique de Paris, Université Paris 6 et CNRS, 98bis blvd. Arago, 75014 Paris (France); Rich, James [CEA, Centre de Saclay, IRFU, 91191 Gif-sur-Yvette (France); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); York, Donald G., E-mail: font@physik.uzh.ch, E-mail: miralda@icc.ub.edu [Department of Astronomy and Astrophysics and The Fermi Institute, Chicago University, 5640 So. Ellis Ave., Chicago, IL 60637 (United States)

2012-11-01

We present the first measurement of the large-scale cross-correlation of Lyα forest absorption and Damped Lyman α systems (DLA), using the 9th Data Release of the Baryon Oscillation Spectroscopic Survey (BOSS). The cross-correlation is clearly detected on scales up to 40h{sup −1}Mpc and is well fitted by the linear theory prediction of the standard Cold Dark Matter model of structure formation with the expected redshift distortions, confirming its origin in the gravitational evolution of structure. The amplitude of the DLA-Lyα cross-correlation depends on only one free parameter, the bias factor of the DLA systems, once the Lyα forest bias factors are known from independent Lyα forest correlation measurements. We measure the DLA bias factor to be b{sub D} = (2.17±0.20)β{sub F}{sup 0.22}, where the Lyα forest redshift distortion parameter β{sub F} is expected to be above unity. This bias factor implies a typical host halo mass for DLAs that is much larger than expected in present DLA models, and is reproduced if the DLA cross section scales with halo mass as M{sub h}{sup α}, with α = 1.1±0.1 for β{sub F} = 1. Matching the observed DLA bias factor and rate of incidence requires that atomic gas remains extended in massive halos over larger areas than predicted in present simulations of galaxy formation, with typical DLA proper sizes larger than 20 kpc in host halos of masses ∼ 10{sup 12}M{sub ☉}. We infer that typical galaxies at z ≅ 2 to 3 are surrounded by systems of atomic clouds that are much more extended than the luminous parts of galaxies and contain ∼ 10% of the baryons in the host halo.

INFERENCES ON THE DISTRIBUTION OF Ly{alpha} EMISSION OF z {approx} 7 AND z {approx} 8 GALAXIES

Energy Technology Data Exchange (ETDEWEB)

Treu, Tommaso; Auger, Matthew W. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Trenti, Michele [University of Colorado, Center for Astrophysics and Space Astronomy, 389-UCB, Boulder, CO 80309 (United States); Stiavelli, Massimo; Bradley, Larry D., E-mail: tt@physics.ucsb.edu [Space Telescope Science Institute, 3700 San Martin Dr, Baltimore MD 21218 (United States)

2012-03-01

Spectroscopic confirmation of galaxies at z {approx} 7 and above has been extremely difficult, owing to a drop in intensity of Ly{alpha} emission in comparison with samples at z {approx} 6. This crucial finding could potentially signal the ending of cosmic reionization. However, it is based on small data sets, often incomplete and heterogeneous in nature. We introduce a flexible Bayesian framework, useful to interpret such evidence. Within this framework, we implement two simple phenomenological models: a smooth one where the distribution of Ly{alpha} is attenuated by a factor {epsilon}{sub s} with respect to z {approx} 6 and a patchy one where a fraction {epsilon}{sub p} is absorbed/non-emitted while the rest is unabsorbed. From a compilation of 39 observed z {approx} 7 galaxies, we find {epsilon}{sub s} = 0.69 {+-} 0.12 and {epsilon}{sub p} = 0.66 {+-} 0.16. The models can be used to compute fractions of emitters above any equivalent width W. For W > 25 A, we find X{sup 25}{sub z=7} = 0.37 {+-} 0.11 (0.14 {+-} 0.06) for galaxies fainter (brighter) than M{sub UV} = -20.25 for the patchy model, consistent with previous work, but with smaller uncertainties by virtue of our full use of the data. At z {approx} 8 we combine new deep (5{sigma} flux limit 10{sup -17} erg s{sup -1} cm{sup -2}) Keck/NIRSPEC observations of a bright Y-dropout identified by our Brightest of Reionization Galaxies Survey, with those of three objects from the literature and find that the inference is inconclusive. We compute predictions for future near-infrared spectroscopic surveys and show that it is challenging but feasible to constrain the distribution of Ly{alpha} emitters at z {approx} 8 and distinguish between models.

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-04-10

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

What is the physical origin of strong Lyα emission? II. Gas kinematics and distribution of Lyα emitters

Energy Technology Data Exchange (ETDEWEB)

Shibuya, Takatoshi; Ouchi, Masami; Ono, Yoshiaki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Nakajima, Kimihiko; Hashimoto, Takuya; Shimasaku, Kazuhiro; Goto, Ryosuke [Department of Astronomy, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan); Rauch, Michael [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Gauthier, Jean-Rene [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Mori, Masao; Umemura, Masayuki, E-mail: shibyatk@icrr.u-tokyo.ac.jp [Center for Computational Sciences, The University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan)

2014-06-10

We present a statistical study of velocities of Lyα, interstellar (IS) absorption, and nebular lines and gas covering fraction for Lyα emitters (LAEs) at z ≅ 2. We make a sample of 22 LAEs with a large Lyα equivalent width (EW) of ≳ 50 Å based on our deep Keck/Low Resolution Imaging Spectrometer (LRIS) observations, in conjunction with spectroscopic data from the Subaru/Fiber Multi Object Spectrograph program and the literature. We estimate the average velocity offset of Lyα from a systemic redshift determined with nebular lines to be Δv {sub Lyα} = 234 ± 9 km s{sup –1}. Using a Kolmogorov-Smirnov test, we confirm the previous claim of Hashimoto et al. that the average Δv {sub Lyα} of LAEs is smaller than that of Lyman break galaxies (LBGs). Our LRIS data successfully identify blueshifted multiple IS absorption lines in the UV continua of four LAEs on an individual basis. The average velocity offset of IS absorption lines from a systemic redshift is Δv {sub IS} = 204 ± 27 km s{sup –1}, indicating LAEs' gas outflow with a velocity comparable to typical LBGs. Thus, the ratio R{sub IS}{sup Lyα}≡Δv{sub Lyα}/Δv{sub IS} of LAEs is around unity, suggestive of low impacts on Lyα transmission by resonant scattering of neutral hydrogen in the IS medium. We find an anti-correlation between Lyα EW and the covering fraction, f{sub c} , estimated from the depth of absorption lines, where f{sub c} is an indicator of average neutral hydrogen column density, N {sub H} {sub I}. The results of our study support the idea that N {sub H} {sub I} is a key quantity determining Lyα emissivity.

Solar Lyman-Alpha Polarization Observation of the Chromosphere and Transition Region by the Sounding Rocket Experiment CLASP

Science.gov (United States)

Narukage, Noriyuki; Kano, Ryohei; Bando, Takamasa; Ishikawa, Ryoko; Kubo, Masahito; Katsukawa, Yukio; Ishikawa, Shinnosuke; Hara, Hiroshi; Suematsu, Yoshinori; Giono, Gabriel;

Cosmological parameter analysis including SDSS Lyα forest and galaxy bias: Constraints on the primordial spectrum of fluctuations, neutrino mass, and dark energy

International Nuclear Information System (INIS)

Seljak, Uros; Makarov, Alexey; McDonald, Patrick; Anderson, Scott F.; Bahcall, Neta A.; Cen, Renyue; Gunn, James E.; Lupton, Robert H.; Schlegel, David J.; Brinkmann, J.; Burles, Scott; Doi, Mamoru; Ivezic, Zeljko; Kent, Stephen; Loveday, Jon; Munn, Jeffrey A.; Nichol, Robert C.; Ostriker, Jeremiah P.; Schneider, Donald P.; Berk, Daniel E. Vanden

2005-01-01

We combine the constraints from the recent Lyα forest analysis of the Sloan Digital Sky Survey (SDSS) and the SDSS galaxy bias analysis with previous constraints from SDSS galaxy clustering, the latest supernovae, and 1st year WMAP cosmic microwave background anisotropies. We find significant improvements on all of the cosmological parameters compared to previous constraints, which highlights the importance of combining Lyα forest constraints with other probes. Combining WMAP and the Lyα forest we find for the primordial slope n s =0.98±0.02. We see no evidence of running, dn/dlnk=-0.003±0.010, a factor of 3 improvement over previous constraints. We also find no evidence of tensors, r 2 model is within the 2-sigma contour, V∝φ 4 is outside the 3-sigma contour. For the amplitude we find σ 8 =0.90±0.03 from the Lyα forest and WMAP alone. We find no evidence of neutrino mass: for the case of 3 massive neutrino families with an inflationary prior, eV and the mass of lightest neutrino is m 1 ν λ =0.72±0.02, w(z=0.3)=-0.98 -0.12 +0.10 , the latter changing to w(z=0.3)=-0.92 -0.10 +0.09 if tensors are allowed. We find no evidence for variation of the equation of state with redshift, w(z=1)=-1.03 -0.28 +0.21 . These results rely on the current understanding of the Lyα forest and other probes, which need to be explored further both observationally and theoretically, but extensive tests reveal no evidence of inconsistency among different data sets used here

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

Science.gov (United States)

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

2014-10-01

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

Line broadening analysis of implosion core conditions at Z using argon K-shell spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Burris-Mog, T.J. [Department of Physics, University of Nevada, Reno, NV 89557 (United States)]. E-mail: burris@physics.unr.edu; Mancini, R.C. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Bailey, J.E. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Chandler, G.A. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Rochau, G. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Dunham, G. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Lake, P.W. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Peterson, K. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Slutz, S.A. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Mehlhorn, T.A. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Golovkin, I.E. [Prism Computational Sciences, Madison, WI 53703 (United States); MacFarlane, J.J. [Prism Computational Sciences, Madison, WI 53703 (United States)

2006-05-15

We report on spectral line broadening analysis of Ar K-shell lines from argon-doped implosion cores driven by a dynamic hohlraum z-pinch. The observed Ar spectra include emissions from the resonance series in H- and He-like Ar ions, i.e., Ly{alpha}, Ly{beta} and Ly{gamma}, and He{alpha}, He{beta}, He{gamma} and He{delta} lines, respectively. The analysis accounts for opacity and Stark broadening to determine electron density, N{sub e}, and areal-density, N{delta}R, values for the ground state populations of H- and He-like Ar ions. Furthermore, these results are combined with the ratio of H- and He-like ground state populations to extract the electron temperature, T{sub e}.

Constraining Reionization with the z ˜ 5-6 Lyα Forest Power Spectrum: The Outlook after Planck

Science.gov (United States)

Oñorbe, J.; Hennawi, J. F.; Lukić, Z.; Walther, M.

2017-09-01

The latest measurements of cosmic microwave background electron-scattering optical depth reported by Planck significantly reduces the allowed space of {{H}} {{I}} reionization models, pointing toward a later ending and/or less extended phase transition than previously believed. Reionization impulsively heats the intergalactic medium (IGM) to ˜ {10}4 {{K}}, and owing to long cooling and dynamical times in the diffuse gas that are comparable to the Hubble time, memory of reionization heating is retained. Therefore, a late-ending reionization has significant implications for the structure of the z˜ 5{--}6 Lyα forest. Using state-of-the-art hydrodynamical simulations that allow us to vary the timing of reionization and its associated heat injection, we argue that extant thermal signatures from reionization can be detected via the Lyα forest power spectrum at 5noise ratio will allow distinguishing between different reionization scenarios.

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

Science.gov (United States)

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

2010-05-01

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

First Spectroscopic Confirmations of z ∼ 7.0 Ly α Emitting Galaxies in the LAGER Survey

Energy Technology Data Exchange (ETDEWEB)

Hu, Weida; Wang, Junxian; Kang, Wenyong; Kong, Xu; Yang, Huan [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zheng, Zhen-Ya; Jiang, Chunyan [CAS Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Shanghai 200030 (China); Malhotra, Sangeeta; Rhoads, James; Gonzalez, Alicia; Tilvi, Vithal [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Infante, Leopoldo [Las Campanas Observatory, Carnegie Institution for Science, Casilla 601, La Serena (Chile); Walker, Alistair R. [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile); Jiang, Linhua [The Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Hibon, Pascale [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago (Chile); Barrientos, L. Felipe; Galaz, Gaspar [Centro de Astroingeniería, Facultad de Física, Pontificia Universidad Católica de Chile, Santiago (Chile); Finkelstein, Steven [Department of Astronomy, The University of Texas at Austin, Austin, TX 78712 (United States); Zheng, XianZhong, E-mail: urverda@mail.ustc.edu.cn, E-mail: jxw@ustc.edu.cn, E-mail: zhengzy@shao.ac.cn, E-mail: Sangeeta.Malhotra@asu.edu, E-mail: James.Rhoads@asu.edu, E-mail: linfante@carnegiescience.edu [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

2017-08-20

Narrowband imaging is a highly successful approach for finding large numbers of high-redshift Ly α emitting galaxies (LAEs) up to z ∼ 6.6. However, at z ≳ 7 there are as of yet only three narrowband selected LAEs with spectroscopic confirmations (two at z ∼ 6.9–7.0, one at z ∼ 7.3), which hinders extensive studies on cosmic reionization and galaxy evolution at this key epoch. We have selected 23 candidate z ∼ 6.9 LAEs in COSMOS field with the large area narrowband survey Lyman-Alpha Galaxies at the End of Reionization (LAGER). In this work, we present spectroscopic follow-up observations of 12 candidates using the Inamori Magellan Areal Camera and Spectrograph on Magellan. For nine of these, the observations are sufficiently deep to detect the expected lines. Ly α emission lines are identified in six sources (yielding a success rate of 2/3), including three luminous LAEs with Ly α luminosities of L {sub Lyα} ∼ 10{sup 43.5} erg s{sup −1}, the highest among known spectroscopically confirmed galaxies at ≳7.0. This triples the sample size of spectroscopically confirmed narrowband selected LAEs at z ≳ 7, and confirms the bright-end bump in the Ly α luminosity function we previously derived based on the photometric sample, supporting a patchy reionization scenario. Two luminous LAEs appear physically linked with a projected distance of 1.1 pMpc and velocity difference of ∼170 km s{sup −1}. They likely sit in a common ionized bubble produced by themselves or with close neighbors, which reduces the intergalactic medium attenuation of Ly α . A tentative narrow N v λ 1240 line is seen in one source, hinting at activity of a central massive black hole with metal-rich line-emitting gas.

Damped Lyman-alpha absorption by disk galaxies with large redshifts. III. Intermediate-resolution spectroscopy

International Nuclear Information System (INIS)

Turnshek, D.A.; Wolfe, A.M.; Lanzetta, K.M.; Briggs, F.H.; Cohen, R.D.

1989-01-01

New intermediate-resolution spectroscopy for six members of a sample of 68 moderate- to high-redshift QSOs is presented. Evidence is reported which indicates that seven strong absorption features in the QSO spectra are due to damped Ly-alpha absorption. A standard curve-of-growth analysis on five of the damped systems is performed, and relevant properties are tabulated and discussed. Six of the seven damped Ly-alpha systems have H I column densities of 2 x 10 to the 20th/sq cm or larger, while the remaining system has an H I column density of about 10 to the 20th/sq cm. It is suggested that damped Ly-alpha systems arise when a sight line intercepts a high-redshift protogalaxy disk containing a quiescent cloud component characterized by high column density and low effective velocity dispersion. At the same time, the sight line usually intercepts a broader turbulent component, which is identified as the halo, characterized by much lower column density and higher effective velocity dispersion. 42 refs

A z = 3 Lyα BLOB ASSOCIATED WITH A DAMPED Lyα SYSTEM PROXIMATE TO ITS BACKGROUND QUASAR

International Nuclear Information System (INIS)

Hennawi, Joseph F.; Prochaska, J. Xavier; Kollmeier, Juna; Zheng Zheng

2009-01-01

We report on the discovery of a bright Lyα blob associated with the z = 3 quasar SDSS J124020.91+145535.6 which is also coincident with strong damped Lyα absorption from a foreground galaxy (a so-called proximate damped Lyα (PDLA) system). The one-dimensional spectrum acquired by the Sloan Digital Sky Survey (SDSS) shows a broad Lyα emission line with a FWHM ≅500 km s -1 and a luminosity of L Lyα = 3.9 x 10 43 erg s -1 superposed on the trough of the PDLA. Follow-up observations using the Keck/LRIS spectrometer confirm that this source has a Lyα nebula with spatial extent exceeding 5'', corresponding to a proper size >39 kpc. Mechanisms for powering the large Lyα luminosity in this nebula are discussed. We use a Monte Carlo radiative transfer simulation to investigate the possibility that the line emission is fluorescent recombination radiation from a kpc-scale PDLA galaxy powered by the ionizing flux of the quasar, but find that the predicted Lyα flux is several orders of magnitude lower than observed. We conclude that the Lyα emission is not associated with the PDLA galaxy at all, but instead is intrinsic to the quasar's host and similar to the extended Lyα f uzzwhich is detected around many active galactic nuclei. PDLAs are natural coronagraphs that block their background quasar at Lyα and we discuss how systems similar to SDSS J124020.91+145535.6 might be used to image the neutral hydrogen in the PDLA galaxy in silhouette against the screen of extended Lyα emission from the background quasar.

Comparison of Solar Fine Structure Observed Simultaneously in Lyα and Mg II h

Science.gov (United States)

Schmit, D.; Sukhorukov, A. V.; De Pontieu, B.; Leenaarts, J.; Bethge, C.; Winebarger, A.; Auchère, F.; Bando, T.; Ishikawa, R.; Kano, R.; Kobayashi, K.; Narukage, N.; Trujillo Bueno, J.

2017-10-01

The Chromospheric Lyman Alpha Spectropolarimeter (CLASP) observed the Sun in H I Lyα during a suborbital rocket flight on 2015 September 3. The Interface Region Imaging Telescope (IRIS) coordinated with the CLASP observations and recorded nearly simultaneous and co-spatial observations in the Mg II h and k lines. The Mg II h and Lyα lines are important transitions, energetically and diagnostically, in the chromosphere. The canonical solar atmosphere model predicts that these lines form in close proximity to each other and so we expect that the line profiles will exhibit similar variability. In this analysis, we present these coordinated observations and discuss how the two profiles compare over a region of quiet Sun at viewing angles that approach the limb. In addition to the observations, we synthesize both line profiles using a 3D radiation-MHD simulation. In the observations, we find that the peak width and the peak intensities are well correlated between the lines. For the simulation, we do not find the same relationship. We have attempted to mitigate the instrumental differences between IRIS and CLASP and to reproduce the instrumental factors in the synthetic profiles. The model indicates that formation heights of the lines differ in a somewhat regular fashion related to magnetic geometry. This variation explains to some degree the lack of correlation, observed and synthesized, between Mg II and Lyα. Our analysis will aid in the definition of future observatories that aim to link dynamics in the chromosphere and transition region.

Comparison of Solar Fine Structure Observed Simultaneously in Ly α and Mg ii h

Energy Technology Data Exchange (ETDEWEB)

Schmit, D. [Bay Area Environmental Research Institute, 625 2nd Street, Suite 209, Petaluma, CA 94952 (United States); Sukhorukov, A. V.; Leenaarts, J. [Institute for Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern NO-0315 Oslo (Norway); De Pontieu, B. [Lockheed Martin Solar and Astrophysics Laboratory, Building 252, 3176 Porter Drive, Palo Alto, CA 94304 (United States); Bethge, C.; Winebarger, A.; Kobayashi, K. [NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States); Auchère, F. [Institut d’Astrophysique Spatiale, CNRS/Univ. Paris-Sud 11, Bâtiment 121, F-91405 Orsay (France); Bando, T.; Kano, R.; Narukage, N. [National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Ishikawa, R. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Bueno, J. Trujillo [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain)

2017-10-01

The Chromospheric Lyman Alpha Spectropolarimeter (CLASP) observed the Sun in H i Ly α during a suborbital rocket flight on 2015 September 3. The Interface Region Imaging Telescope ( IRIS ) coordinated with the CLASP observations and recorded nearly simultaneous and co-spatial observations in the Mg ii h and k lines. The Mg ii h and Ly α lines are important transitions, energetically and diagnostically, in the chromosphere. The canonical solar atmosphere model predicts that these lines form in close proximity to each other and so we expect that the line profiles will exhibit similar variability. In this analysis, we present these coordinated observations and discuss how the two profiles compare over a region of quiet Sun at viewing angles that approach the limb. In addition to the observations, we synthesize both line profiles using a 3D radiation-MHD simulation. In the observations, we find that the peak width and the peak intensities are well correlated between the lines. For the simulation, we do not find the same relationship. We have attempted to mitigate the instrumental differences between IRIS and CLASP and to reproduce the instrumental factors in the synthetic profiles. The model indicates that formation heights of the lines differ in a somewhat regular fashion related to magnetic geometry. This variation explains to some degree the lack of correlation, observed and synthesized, between Mg ii and Ly α . Our analysis will aid in the definition of future observatories that aim to link dynamics in the chromosphere and transition region.

The Lyα Reference Sample

DEFF Research Database (Denmark)

Ostlin, Goran; Hayes, Matthew; Duval, Florent

2014-01-01

The Lyα Reference Sample (LARS) is a substantial program with the Hubble Space Telescope (HST) that provides a sample of local universe laboratory galaxies in which to study the detailed astrophysics of the visibility and strength of the Lyαline of neutral hydrogen. Lyα is the dominant spectral...... are produced (whether or not they escape), we demanded an Hα equivalent width W(Hα) ≥100 Å. The final sample of 14 galaxies covers far-UV (FUV, λ ~ 1500 Å) luminosities that overlap with those of high-z Lyα emitters (LAEs) and Lyman break galaxies (LBGs), making LARS a valid comparison sample. We present......) but strongly asymmetric Lyα emission. Spectroscopy from the Cosmic Origins Spectrograph on board HST centered on the brightest UV knot shows a moderate outflow in the neutral interstellar medium (probed by low ionization stage absorption features) and Lyα emission with an asymmetric profile. Radiative transfer...

Ly α and UV Sizes of Green Pea Galaxies

Energy Technology Data Exchange (ETDEWEB)

Yang, Huan; Wang, Junxian [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China (China); Malhotra, Sangeeta; Rhoads, James E.; Jiang, Tianxing [Arizona State University, School of Earth and Space Exploration (United States); Leitherer, Claus [Space Telescope Science Institute, 3700 San Martin Dr, Baltimore, MD 21218 (United States); Wofford, Aida, E-mail: huan.y@asu.edu [National Autonomous University of Mexico, Institute of Astronomy (Mexico)

2017-03-20

Green Peas are nearby analogs of high-redshift Ly α -emitting galaxies (LAEs). To probe their Ly α escape, we study the spatial profiles of Ly α and UV continuum emission of 24 Green Pea galaxies using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope . We extract the spatial profiles of Ly α emission from their 2D COS spectra, and of the UV continuum from both 2D spectra and NUV images. The Ly α emission shows more extended spatial profiles than the UV continuum, in most Green Peas. The deconvolved full width at half maximum of the Ly α spatial profile is about 2–4 times that of the UV continuum, in most cases. Because Green Peas are analogs of high z LAEs, our results suggest that most high- z LAEs probably have larger Ly α sizes than UV sizes. We also compare the spatial profiles of Ly α photons at blueshifted and redshifted velocities in eight Green Peas with sufficient data quality, and find that the blue wing of the Ly α line has a larger spatial extent than the red wing in four Green Peas with comparatively weak blue Ly α line wings. We show that Green Peas and MUSE z = 3–6 LAEs have similar Ly α and UV continuum sizes, which probably suggests that starbursts in both low- z and high- z LAEs drive similar gas outflows illuminated by Ly α light. Five Lyman continuum (LyC) leakers in this sample have similar Ly α to UV continuum size ratios (∼1.4–4.3) to the other Green Peas, indicating that their LyC emissions escape through ionized holes in the interstellar medium.

Minihalo model for the low-redshift Lyα absorbers revisited

Directory of Open Access Journals (Sweden)

Lalović A.

2008-01-01

Full Text Available We reconsider the basic properties of the classical minihalo model of Rees and Milgrom in light of the new work, both observational (on 'dark galaxies' and masses of baryonic haloes and theoretical (on the cosmological mass function and the history of star formation. In particular, we show that more detailed models of ionized gas in haloes of dark matter following isothermal and Navarro-Frenk-White density profile can effectively reproduce particular aspects of the observed column density distribution function in a heterogeneous sample of low- and intermediate-redshift Lyα forest absorption lines.

What is the physical origin of strong Lyα emission? I. Demographics of Lyα emitter structures

International Nuclear Information System (INIS)

Shibuya, Takatoshi; Ouchi, Masami; Yuma, Suraphong; Nakajima, Kimihiko; Hashimoto, Takuya; Shimasaku, Kazuhiro; Mori, Masao; Umemura, Masayuki

2014-01-01

We present the results of structure analyses for a large sample of 426 Lyα emitters (LAEs) at z ∼ 2.2 that are observed with the Hubble Space Telescope/Advanced Camera for Surveys and WFC3-IR during deep extra-galactic legacy surveys. We confirm that the merger fraction and the average ellipticity of LAE's stellar component are 10%-30% and 0.4-0.6, respectively, that are comparable with previous study results. We successfully identify that some LAEs have a spatial offset between Lyα and stellar-continuum emission peaks, δ Lyα , by ∼2.5-4 kpc beyond our statistical errors. To uncover the physical origin of strong Lyα emission found in LAEs, we investigate the Lyα equivalent width (EW) dependences of three structural parameters: merger fraction, δ Lyα , and ellipticity of stellar distribution in the range of EW(Lyα) = 20-250 Å. Contrary to expectations, we find that the merger fraction does not significantly increase with Lyα EW. We reveal an anti-correlation between δ Lyα and EW(Lyα) using a Kolmogorov-Smirnov (K-S) test. There is a trend that the LAEs with a large Lyα EW have a small ellipticity. This is consistent with the recent theoretical claims that Lyα photons can more easily escape from face-on disks having a small ellipticity, due to less inter-stellar gas along the line of sight, although our K-S test indicates that this trend is not statistically significant. Our results of Lyα-EW dependence generally support the idea that an H I column density is a key quantity determining Lyα emissivity.

SEURAT: SPH scheme extended with ultraviolet line radiative transfer

Science.gov (United States)

Abe, Makito; Suzuki, Hiroyuki; Hasegawa, Kenji; Semelin, Benoit; Yajima, Hidenobu; Umemura, Masayuki

2018-05-01

We present a novel Lyman alpha (Ly α) radiative transfer code, SEURAT (SPH scheme Extended with Ultraviolet line RAdiative Transfer), where line scatterings are solved adaptively with the resolution of the smoothed particle hydrodynamics (SPH). The radiative transfer method implemented in SEURAT is based on a Monte Carlo algorithm in which the scattering and absorption by dust are also incorporated. We perform standard test calculations to verify the validity of the code; (i) emergent spectra from a static uniform sphere, (ii) emergent spectra from an expanding uniform sphere, and (iii) escape fraction from a dusty slab. Thereby, we demonstrate that our code solves the {Ly} α radiative transfer with sufficient accuracy. We emphasize that SEURAT can treat the transfer of {Ly} α photons even in highly complex systems that have significantly inhomogeneous density fields. The high adaptivity of SEURAT is desirable to solve the propagation of {Ly} α photons in the interstellar medium of young star-forming galaxies like {Ly} α emitters (LAEs). Thus, SEURAT provides a powerful tool to model the emergent spectra of {Ly} α emission, which can be compared to the observations of LAEs.

Molecular Mechanism of Enhanced Anticancer Effect of Nanoparticle Formulated LY2835219 via p16-CDK4/6-pRb Pathway in Colorectal Carcinoma Cell Line

Directory of Open Access Journals (Sweden)

Xu Tang

2016-01-01

Full Text Available LY2835219 is a dual inhibitor to CDK4 and CDK6. This study was to prepare LY2835219-loaded chitosan nanoparticles (CNP/LY and LY2835219-loaded hyaluronic acid-conjugated chitosan nanoparticles (HACNP/LY and revealed their anticancer effect and influence on p16-CDK4/6-pRb pathway against colon cell line. The nanoparticle sizes of CNP/LY and HACNP/LY were approximately 195±39.6 nm and 217±31.1 nm, respectively. The zeta potentials of CNP/LY and HACNP/LY were 37.3±1.5 mV and 30.3±2.2 mV, respectively. And the preparation process showed considerable drug encapsulation efficiency and loading efficiency. LY2835219, CNP/LY, and HACNP/LY inhibited HT29 cell proliferation with 0.68, 0.54, and 0.30 μM of IC50, respectively. G1 phase was arrested by LY2835219 and its formulations. Furthermore, inhibition of CDK4/6 by LY2835219 formulations induced CDK4, CDK6, cyclin D1, and pRb decrease and p16 increase at both protein and mRNA levels. Overall, nanoparticle formulated LY2835219 could enhance the cytotoxicity and cell cycle arrest, and HACNP/LY strengthened the trend furtherly compared to CNP/LY. It is the first time to demonstrate the anticancer effect and mechanism against HT29 by LY2835219 and its nanoparticles. The drug and its nanoparticle formulations delay the cell growth and arrest cell cycle through p16-CDK4/6-pRb pathway, while the nanoparticle formulated LY2835219 could strengthen the process.

GREEN PEA GALAXIES REVEAL SECRETS OF Lyα ESCAPE

Energy Technology Data Exchange (ETDEWEB)

Yang, Huan; Wang, Junxian [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China (China); Malhotra, Sangeeta; Rhoads, James E. [Arizona State University, School of Earth and Space Exploration (United States); Gronke, Max; Dijkstra, Mark [Institute of Theoretical Astrophysics, University of Oslo (Norway); Jaskot, Anne [Smith College, Northampton, MA (United States); Zheng, Zhenya, E-mail: yanghuan@mail.ustc.edu.cn, E-mail: huan.y@asu.edu, E-mail: Sangeeta.Malhotra@asu.edu, E-mail: James.Rhoads@asu.edu [Pontificia Universidad Católica de Chile, Santiago (Chile)

2016-04-01

We analyze archival Lyα spectra of 12 “Green Pea” galaxies observed with the Hubble Space Telescope, model their Lyα profiles with radiative transfer models, and explore the dependence of the Lyα escape fraction on various properties. Green Pea galaxies are nearby compact starburst galaxies with [O iii] λ5007 equivalent widths (EWs) of hundreds of Å. All 12 Green Pea galaxies in our sample show Lyα lines in emission, with an Lyα EW distribution similar to high-redshift Lyα emitters. Combining the optical and UV spectra of Green Pea galaxies, we estimate their Lyα escape fractions and find correlations between Lyα escape fraction and kinematic features of Lyα profiles. The escape fraction of Lyα in these galaxies ranges from 1.4% to 67%. We also find that the Lyα escape fraction depends strongly on metallicity and moderately on dust extinction. We compare their high-quality Lyα profiles with single H i shell radiative transfer models and find that the Lyα escape fraction anticorrelates with the derived H i column densities. Single-shell models fit most Lyα profiles well, but not the ones with the highest escape fractions of Lyα. Our results suggest that low H i column density and low metallicity are essential for Lyα escape and make a galaxy an Lyα emitter.

The effect of high column density systems on the measurement of the Lyman-α forest correlation function

Energy Technology Data Exchange (ETDEWEB)

Font-Ribera, Andreu [Institut de Ciències de l' Espai (IEEC-CSIC), E. de Ciències, Torre C5, Bellaterra, Catalonia (Spain); Miralda-Escudé, Jordi, E-mail: font@physik.uzh.ch, E-mail: miralda@icc.ub.edu [Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Catalonia (Spain)

2012-07-01

We present a study of the effect of High Column Density (HCD) systems on the Lyα forest correlation function on large scales. We study the effect both numerically, by inserting HCD systems on mock spectra for a specific model, and analytically, in the context of two-point correlations and linear theory. We show that the presence of HCDs substantially contributes to the noise of the correlation function measurement, and systematically alters the measured redshift-space correlation function of the Lyα forest, increasing the value of the density bias factor and decreasing the redshift distortion parameter β{sub α} of the Lyα forest. We provide simple formulae for corrections on these derived parameters, as a function of the mean effective optical depth and bias factor of the host halos of the HCDs, and discuss the conditions under which these expressions should be valid. In practice, precise corrections to the measured parameters of the Lyα forest correlation for the HCD effects are more complex than the simple analytical approximations we present, owing to non-linear effects of the damped wings of the HCD systems and the presence of three-point terms. However, we conclude that an accurate correction for these HCD effects can be obtained numerically and calibrated with observations of the HCD-Lyα cross-correlation. We also discuss an analogous formalism to treat and correct for the contaminating effect of metal lines overlapping the Lyα forest spectra.

The physical properties and evolution of Lyα emitting galaxies

Science.gov (United States)

Pentericci, L.; Grazian, A.; Fontana, A.

2009-05-01

A significant fraction of high redshift starburst galaxies presents strong Lyα emission. Understanding the nature of these galaxies is important to assess the role they played in the early Universe and to shed light on the relation between the narrow band selected Lyα emitters and the Lyman break galaxies: are the Lyα emitters a subset of the general LBG population? or do they represent the youngest galaxies in their early phases of formation? We studied a sample of UV continuum selected galaxies from z~2.5 to z~6 (U, B, V and i-dropouts) from the GOODS-South survey, that have been observed spectroscopically. Using the GOODS-MUSIC catalog we investigated their physical properties, such as total masses, ages, SFRs, extinction etc as determined from a spectrophotometric fit to the multi-wavelength (U band to mid-IR) SEDs, and their dependence on the emission line characteristics. In particular we determined the nature of the LBGs with Lyα in emission and compared them to the properties of narrow band selected Lyα emitters. For U and B-dropouts we also compared the properties of LBGs with and without the Lyα emission line.

GRB 130606A AS A PROBE OF THE INTERGALACTIC MEDIUM AND THE INTERSTELLAR MEDIUM IN A STAR-FORMING GALAXY IN THE FIRST Gyr AFTER THE BIG BANG

Energy Technology Data Exchange (ETDEWEB)

Chornock, Ryan; Berger, Edo; Lunnan, Ragnhild; Drout, Maria R.; Fong Wenfai; Laskar, Tanmoy [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fox, Derek B. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Roth, Katherine C., E-mail: rchornock@cfa.harvard.edu [Gemini Observatory, 670 North Aohoku Place, Hilo, HI 96720 (United States)

2013-09-01

We present high signal-to-noise ratio Gemini and MMT spectroscopy of the optical afterglow of the gamma-ray burst (GRB) 130606A at redshift z = 5.913, discovered by Swift. This is the first high-redshift GRB afterglow to have spectra of comparable quality to those of z Almost-Equal-To 6 quasars. The data exhibit a smooth continuum at near-infrared wavelengths that is sharply cut off blueward of 8410 A due to absorption from Ly{alpha} at redshift z Almost-Equal-To 5.91, with some flux transmitted through the Ly{alpha} forest between 7000 and 7800 A. We use column densities inferred from metal absorption lines to constrain the metallicity of the host galaxy between a lower limit of [Si/H] {approx}> -1.7 and an upper limit of [S/H] {approx}< -0.5 set by the non-detection of S II absorption. We demonstrate consistency between the dramatic evolution in the transmission fraction of Ly{alpha} seen in this spectrum over the redshift range z = 4.9-5.85 with that previously measured from observations of high-redshift quasars. There is an extended redshift interval of {Delta}z = 0.12 in the Ly{alpha} forest at z = 5.77 with no detected transmission, leading to a 3{sigma} upper limit on the mean Ly{alpha} transmission fraction of {approx}<0.2% (or {tau}{sub GP}{sup eff} (Ly{alpha}) > 6.4). This is comparable to the lowest-redshift Gunn-Peterson troughs found in quasar spectra. Some Ly{beta} and Ly{gamma} transmission is detected in this redshift window, indicating that it is not completely opaque, and hence that the intergalactic medium (IGM) is nonetheless mostly ionized at these redshifts. We set a 2{sigma} upper limit of 0.11 on the neutral fraction of the IGM at the redshift of the GRB from the lack of a Ly{alpha} red damping wing, assuming a model with a constant neutral density. GRB 130606A thus for the first time realizes the promise of GRBs as probes of the first galaxies and cosmic reionization.

The properties of the brightest Lyα emitters at z=5.7

Science.gov (United States)

Lidman, C.; Hayes, M.; Jones, D. H.; Schaerer, D.; Westra, E.; Tapken, C.; Meisenheimer, K.; Verhamme, A.

2012-03-01

We use deep Very Large Telescope (VLT) optical and near-infrared spectroscopy and deep Spitzer/IRAC imaging to examine the properties of two of the most luminous Lyα emitters at z= 5.7. The continuum redward of the Lyα line is clearly detected in both objects, thus facilitating a relatively accurate measurement (10-20 per cent uncertainties) of the observed rest-frame equivalent widths, which are around 160 Å for both objects. Through detailed modelling of the profile of the Lyα line with a 3D Monte Carlo radiative transfer code, we estimate the intrinsic rest-frame equivalent width of Lyα and find values that are around 300 Å, which is at the upper end of the range allowed for very young, moderately metal-poor star-forming galaxies. However, the uncertainties are large and values as high as 700 Å are permitted by the data. Both Lyα emitters are detected at 3.6 ?m in deep images taken with the Spitzer Space Telescope. We use these measurements, the measurement of the continuum redward of Lyα and other photometry to constrain the spectral energy distributions of these very luminous Lyα emitters and to compare them with three similar Lyα emitters from the literature. The contribution from nebular emission is included in our models: excluding it results in significantly higher masses. Four of the five Lyα emitters have masses of the order of ˜109 M⊙ and fairly high specific star formation rates (≳10-100 Gyr-1). While our two Lyα emitters appear similar in terms of the observed Lyα rest-frame equivalent width, they are quite distinct from each other in terms of age, mass and star formation history. Evidence for dust is found in all objects, and emission from nebular lines often makes a dominant contribution to the rest-frame 3.6 ?m flux. Rich in emission lines, these objects are prime targets for the next generation of extremely large telescopes, the James Webb Space Telescope (JWST) and the Atacama Large Millimeter Array (ALMA). a Initial 2σ lower

Clustering of galaxies near damped Lyman-alpha systems with (z) = 2.6

Science.gov (United States)

Wolfe, A. M

1993-01-01

The galaxy two-point correlation function, xi, at (z) = 2.6 is determined by comparing the number of Ly-alpha-emitting galaxies in narrowband CCD fields selected for the presence of damped L-alpha absorption to their number in randomly selected control fields. Comparisons between the presented determination of (xi), a density-weighted volume average of xi, and model predictions for (xi) at large redshifts show that models in which the clustering pattern is fixed in proper coordinates are highly unlikely, while better agreement is obtained if the clustering pattern is fixed in comoving coordinates. Therefore, clustering of Ly-alpha-emitting galaxies around damped Ly-alpha systems at large redshifts is strong. It is concluded that the faint blue galaxies are drawn from a parent population different from normal galaxies, the presumed offspring of damped Ly-alpha systems.

The cross-correlation between 21 cm intensity mapping maps and the Lyα forest in the post-reionization era

Energy Technology Data Exchange (ETDEWEB)

Carucci, Isabella P. [SISSA—International School for Advanced Studies, Via Bonomea 265, 34136 Trieste (Italy); Villaescusa-Navarro, Francisco [Center for Computational Astrophysics, 160 5th Avenue, New York, NY, 10010 (United States); Viel, Matteo, E-mail: ipcarucci@sissa.it, E-mail: fvillaescusa@simonsfoundation.org, E-mail: viel@oats.inaf.it [INAF—Osservatorio Astronomico di Trieste, Via Tiepolo 11, 34143, Trieste (Italy)

2017-04-01

We investigate the cross-correlation signal between 21cm intensity mapping maps and the Lyα forest in the fully non-linear regime using state-of-the-art hydrodynamic simulations. The cross-correlation signal between the Lyα forest and 21cm maps can provide a coherent and comprehensive picture of the neutral hydrogen (HI) content of our Universe in the post-reionization era, probing both its mass content and volume distribution. We compute the auto-power spectra of both fields together with their cross-power spectrum at z = 2.4 and find that on large scales the fields are completely anti-correlated. This anti-correlation arises because regions with high (low) 21cm emission, such as those with a large (low) concentration of damped Lyα systems, will show up as regions with low (high) transmitted flux. We find that on scales smaller than k ≅ 0.2 h Mpc{sup −1} the cross-correlation coefficient departs from −1, at a scale where non-linearities show up. We use the anisotropy of the power spectra in redshift-space to determine the values of the bias and of the redshift-space distortion parameters of both fields. We find that the errors on the value of the cosmological and astrophysical parameters could decrease by 30% when adding data from the cross-power spectrum, in a conservative analysis. Our results point out that linear theory is capable of reproducing the shape and amplitude of the cross-power up to rather non-linear scales. Finally, we find that the 21cm-Lyα cross-power spectrum can be detected by combining data from a BOSS-like survey together with 21cm intensity mapping observations by SKA1-MID with a S/N ratio higher than 3 in k element of [0.06,1] h Mpc{sup −1}. We emphasize that while the shape and amplitude of the 21cm auto-power spectrum can be severely affected by residual foreground contamination, cross-power spectra will be less sensitive to that and therefore can be used to identify systematics in the 21cm maps.

SPATIALLY RESOLVED GAS KINEMATICS WITHIN A Lyα NEBULA: EVIDENCE FOR LARGE-SCALE ROTATION

Energy Technology Data Exchange (ETDEWEB)

Prescott, Moire K. M. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Martin, Crystal L. [Department of Physics, Broida Hall, Mail Code 9530, University of California, Santa Barbara, CA 93106 (United States); Dey, Arjun, E-mail: mkmprescott@dark-cosmology.dk [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)

2015-01-20

We use spatially extended measurements of Lyα as well as less optically thick emission lines from an ≈80 kpc Lyα nebula at z ≈ 1.67 to assess the role of resonant scattering and to disentangle kinematic signatures from Lyα radiative transfer effects. We find that the Lyα, C IV, He II, and C III] emission lines all tell a similar story in this system, and that the kinematics are broadly consistent with large-scale rotation. First, the observed surface brightness profiles are similar in extent in all four lines, strongly favoring a picture in which the Lyα photons are produced in situ instead of being resonantly scattered from a central source. Second, we see low kinematic offsets between Lyα and the less optically thick He II line (∼100-200 km s{sup –1}), providing further support for the argument that the Lyα and other emission lines are all being produced within the spatially extended gas. Finally, the full velocity field of the system shows coherent velocity shear in all emission lines: ≈500 km s{sup –1} over the central ≈50 kpc of the nebula. The kinematic profiles are broadly consistent with large-scale rotation in a gas disk that is at least partially stable against collapse. These observations suggest that the Lyα nebula represents accreting material that is illuminated by an offset, hidden active galactic nucleus or distributed star formation, and that is undergoing rotation in a clumpy and turbulent gas disk. With an implied mass of M(

The large-scale quasar-Lyman α forest cross-correlation from BOSS

Energy Technology Data Exchange (ETDEWEB)

Font-Ribera, Andreu [Institute of Theoretical Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich (Switzerland); Arnau, Eduard [Institut de Ciències del Cosmos (IEEC/UB), Martí i Franquès 1, 08028 Barcelona, Catalonia (Spain); Miralda-Escudé, Jordi, E-mail: font@physik.uzh.ch, E-mail: edu.arnau.lazaro@gmail.com, E-mail: miralda@icc.ub.edu [Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Catalonia (Spain); and others

2013-05-01

We measure the large-scale cross-correlation of quasars with the Lyα forest absorption in redshift space, using ∼ 60000 quasar spectra from Data Release 9 (DR9) of the Baryon Oscillation Spectroscopic Survey (BOSS). The cross-correlation is detected over a wide range of scales, up to comoving separations r of 80 h{sup −1}Mpc. For r > 15 h{sup −1}Mpc, we show that the cross-correlation is well fitted by the linear theory prediction for the mean overdensity around a quasar host halo in the standard ΛCDM model, with the redshift distortions indicative of gravitational evolution detected at high confidence. Using previous determinations of the Lyα forest bias factor obtained from the Lyα autocorrelation, we infer the quasar bias factor to be b{sub q} = 3.64{sup +0.13}{sub −0.15} at a mean redshift z = 2.38, in agreement with previous measurements from the quasar auto-correlation. We also obtain a new estimate of the Lyα forest redshift distortion factor, β{sub F} = 1.1±0.15, slightly larger than but consistent with the previous measurement from the Lyα forest autocorrelation. The simple linear model we use fails at separations r < 15h{sup −1}Mpc, and we show that this may reasonably be due to the enhanced ionization due to radiation from the quasars. We also provide the expected correction that the mass overdensity around the quasar implies for measurements of the ionizing radiation background from the line-of-sight proximity effect.

The large-scale quasar-Lyman α forest cross-correlation from BOSS

International Nuclear Information System (INIS)

Font-Ribera, Andreu; Arnau, Eduard; Miralda-Escudé, Jordi

2013-01-01

We measure the large-scale cross-correlation of quasars with the Lyα forest absorption in redshift space, using ∼ 60000 quasar spectra from Data Release 9 (DR9) of the Baryon Oscillation Spectroscopic Survey (BOSS). The cross-correlation is detected over a wide range of scales, up to comoving separations r of 80 h −1 Mpc. For r > 15 h −1 Mpc, we show that the cross-correlation is well fitted by the linear theory prediction for the mean overdensity around a quasar host halo in the standard ΛCDM model, with the redshift distortions indicative of gravitational evolution detected at high confidence. Using previous determinations of the Lyα forest bias factor obtained from the Lyα autocorrelation, we infer the quasar bias factor to be b q = 3.64 +0.13 −0.15 at a mean redshift z = 2.38, in agreement with previous measurements from the quasar auto-correlation. We also obtain a new estimate of the Lyα forest redshift distortion factor, β F = 1.1±0.15, slightly larger than but consistent with the previous measurement from the Lyα forest autocorrelation. The simple linear model we use fails at separations r −1 Mpc, and we show that this may reasonably be due to the enhanced ionization due to radiation from the quasars. We also provide the expected correction that the mass overdensity around the quasar implies for measurements of the ionizing radiation background from the line-of-sight proximity effect

LyGDI expression in HeLa cells increased its sensitivity to radiation-induced apoptosis

International Nuclear Information System (INIS)

Zhou Xinwen; Xu Yaxiang

2006-01-01

Objective: In order to confirm whether LyGDI has apoptotic signal transduction function and can increase the apoptotic rate of radiation-induced cell death, the lyGDI and mutant D19lyGDI gene, which constructed with the pCDNA3. 1 His A, were transfected into no-endogenous lyGDI HeLa cells. Methods Transient expressions of lyGDI and D19lyGDI in HeLa cells were analyzed by Western blot using anti-mono antibody of LyGDI and Xpress tag. Cell apoptosis was assayed with Annexin V-FITC apoptosis kit. To select stable clone, the transferred HeLa cells had been maintained in G418 medium for 3 weeks, then a cell line, which stably expressed LyGDI and mutant D19lyGDI, was selected. The selected cell line was irradiated with 12 Gy 60 Co y-rays. Caspase-3 activity of the cells was determined by Western blot and cell viability by clone-forming assay after 48 hours post-irradiation culture. Results: Western blot and Annexin V-FITC apoptotic analysis revealed that lyGDI and D19lyGDI transient expressions in HeLa cells induced apoptosis; Caspase-3 activity measurement and clone-forming assay showed that lyGDI increased sensitivity to radiation-induced cell apoptosis. Conclusions: lyGDI performs function in apoptosis signal transduction, its expression in HeLa cells can increase the sensitivity to radiation-induced cell apoptosis. (authors)

Unlocking the Full Potential of Extragalactic Lyα through Its Polarization Properties

Science.gov (United States)

Eide, Marius B.; Gronke, Max; Dijkstra, Mark; Hayes, Matthew

2018-04-01

Lyα is a powerful astrophysical probe. Not only is it ubiquitous at high redshifts, it is also a resonant line, making Lyα photons scatter. This scattering process depends on the physical conditions of the gas through which Lyα propagates, and these conditions are imprinted on observables such as the Lyα spectrum and its surface brightness profile. In this work, we focus on a less-used observable capable of probing any scattering process: polarization. We implement the density matrix formalism of polarization into the Monte Carlo radiative transfer code tlac. This allows us to treat it as a quantum mechanical process where single photons develop and lose polarization from scatterings in arbitrary gas geometries. We explore static and expanding ellipsoids, biconical outflows, and clumpy multiphase media. We find that photons become increasingly polarized as they scatter and diffuse into the wings of the line profiles, making scattered Lyα polarized in general. The degree and orientation of Lyα polarization depends on the kinematics and distribution of the scattering H I gas. We find that it generally probes spatial or velocity space asymmetries and aligns itself tangentially to the emission source. We show that the mentioned observables, when studied separately, can leave similar signatures for different source models. We conclude by revealing how a joint analysis of the Lyα spectra, surface brightness profiles, and polarization can break these degeneracies and help us extract unique physical information on galaxies and their environments from their strongest, most prominent emission line.

Weak lensing of the Lyman α forest

Science.gov (United States)

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

2018-06-01

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

Boosting Lyα and He II λ1640 Line Fluxes from Population III Galaxies: Stochastic IMF Sampling and Departures from Case-B

Science.gov (United States)

Mas-Ribas, Lluís; Dijkstra, Mark; Forero-Romero, Jaime E.

2016-12-01

We revisit calculations of nebular hydrogen Lyα and He II λ1640 line strengths for Population III (Pop III) galaxies, undergoing continuous, and bursts of, star formation. We focus on initial mass functions (IMFs) motivated by recent theoretical studies, which generally span a lower range of stellar masses than earlier works. We also account for case-B departures and the stochastic sampling of the IMF. In agreement with previous work, we find that departures from case-B can enhance the Lyα flux by a factor of a few, but we argue that this enhancement is driven mainly by collisional excitation and ionization, and not due to photoionization from the n = 2 state of atomic hydrogen. The increased sensitivity of the Lyα flux to the high-energy end of the galaxy spectrum makes it more subject to stochastic sampling of the IMF. The latter introduces a dispersion in the predicted nebular line fluxes around the deterministic value by as much as a factor of ˜4. In contrast, the stochastic sampling of the IMF has less impact on the emerging Lyman Werner photon flux. When case-B departures and stochasticity effects are combined, nebular line emission from Pop III galaxies can be up to one order of magnitude brighter than predicted by “standard” calculations that do not include these effects. This enhances the prospects for detection with future facilities such as the James Webb Space Telescope and large, ground-based telescopes.

A young star-forming galaxy at z = 3.5 with an extended Ly\\,$α$ halo seen with MUSE

DEFF Research Database (Denmark)

Patrício, Vera; Richard, Johan; Verhamme, Anne

2016-01-01

.5$, observed with MUSE, for which we obtain 2D resolved spatial information of Ly$\\alpha$ and, for the first time, of CIII] emission. The exceptional signal-to-noise of the data reveals UV emission and absorption lines rarely seen at these redshifts, allowing us to derive important physical properties (T$_e......\\sim$15600 K, n$_e\\sim$300 cm$^{-3}$, covering fraction f$_c\\sim0.4$) using multiple diagnostics. Inferred stellar and gas-phase metallicities point towards a low metallicity object (Z$_{\\mathrm{stellar}}$ = $\\sim$ 0.07 Z$_\\odot$ and Z$_{\\mathrm{ISM}}$ $...

THE REST-FRAME OPTICAL SPECTROSCOPIC PROPERTIES OF LY α -EMITTERS AT z  ∼ 2.5: THE PHYSICAL ORIGINS OF STRONG LY α EMISSION

Energy Technology Data Exchange (ETDEWEB)

Trainor, Ryan F. [Department of Astronomy, University of California, Berkeley, 501 Campbell Hall, Berkeley, CA 94720 (United States); Strom, Allison L.; Steidel, Charles C. [Cahill Center for Astrophysics, MC 249-17, 1200 E California Boulevard, Pasadena, CA 91125 (United States); Rudie, Gwen C., E-mail: trainor@berkeley.edu [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

2016-12-01

We present the rest-frame optical spectroscopic properties of 60 faint ( R {sub AB} ∼ 27; L ∼ 0.1 L {sub *}) Ly α -selected galaxies (LAEs) at z  ≈ 2.56. These LAEs also have rest-UV spectra of their Ly α emission line morphologies, which trace the effects of interstellar and circumgalactic gas on the escape of Ly α photons. We find that the LAEs have diverse rest-optical spectra, but their average spectroscopic properties are broadly consistent with the extreme low-metallicity end of the populations of continuum-selected galaxies selected at z  ≈ 2–3. In particular, the LAEs have extremely high [O iii] λ 5008/H β ratios (log([O iii]/H β ) ∼ 0.8) and low [N ii] λ 6585/H α ratios (log([N ii]/H α ) < 1.15). Coupled with a detection of the [O iii] λ 4364 auroral line, these measurements indicate that the star-forming regions in faint LAEs are characterized by high electron temperatures (T{sub e} ≈ 1.8 × 10{sup 4} K), low oxygen abundances (12 + log(O/H) ≈ 8.04, Z{sub neb} ≈ 0.22 Z {sub ⊙}), and high excitations with respect to their more luminous continuum-selected analogs. Several of our faintest LAEs have line ratios consistent with even lower metallicities, including six with 12 + log(O/H) ≈ 6.9–7.4 (Z {sub neb} ≈ 0.02–0.05 Z{sub ⊙}). We interpret these observations in light of new models of stellar evolution (including binary interactions) that have been shown to produce long-lived populations of hot, massive stars at low metallicities. We find that strong, hard ionizing continua are required to reproduce our observed line ratios, suggesting that faint galaxies are efficient producers of ionizing photons and important analogs of reionization-era galaxies. Furthermore, we investigate the physical trends accompanying Ly α emission across the largest current sample of combined Ly α and rest-optical galaxy spectroscopy, including both the 60 KBSS-Ly α LAEs and 368 more luminous galaxies at similar redshifts. We

BOOSTING LY α   AND He ii λ 1640 LINE FLUXES FROM POPULATION III GALAXIES: STOCHASTIC IMF SAMPLING AND DEPARTURES FROM CASE-B

International Nuclear Information System (INIS)

Mas-Ribas, Lluís; Dijkstra, Mark; Forero-Romero, Jaime E.

2016-01-01

We revisit calculations of nebular hydrogen Ly α and He ii λ 1640 line strengths for Population III (Pop III) galaxies, undergoing continuous, and bursts of, star formation. We focus on initial mass functions (IMFs) motivated by recent theoretical studies, which generally span a lower range of stellar masses than earlier works. We also account for case-B departures and the stochastic sampling of the IMF. In agreement with previous work, we find that departures from case-B can enhance the Ly α flux by a factor of a few, but we argue that this enhancement is driven mainly by collisional excitation and ionization, and not due to photoionization from the n  = 2 state of atomic hydrogen. The increased sensitivity of the Ly α flux to the high-energy end of the galaxy spectrum makes it more subject to stochastic sampling of the IMF. The latter introduces a dispersion in the predicted nebular line fluxes around the deterministic value by as much as a factor of ∼4. In contrast, the stochastic sampling of the IMF has less impact on the emerging Lyman Werner photon flux. When case-B departures and stochasticity effects are combined, nebular line emission from Pop III galaxies can be up to one order of magnitude brighter than predicted by “standard” calculations that do not include these effects. This enhances the prospects for detection with future facilities such as the James Webb Space Telescope and large, ground-based telescopes.

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

Science.gov (United States)

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

2009-08-28

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

Lyman Alpha Searches at Redshift Z>7

Science.gov (United States)

Willis, Jon

2007-05-01

The ZEN survey is a narrow J-band survey for Ly-alpha emitting galaxies at z > 7. I will briefly review the pros and cons of narrow band observations before summarising the ZEN1 and ZEN2 searches based upon deep ISAAC pointings. I will then present ZEN3, consisting of wide field, narrow band observations of two fields using the CFHT WIRCam facility. I will conclude by reviewing the current sample of candidates and what we have learned about the z > 7 Ly-alpha emitting population.

The Mean Metal-line Absorption Spectrum of Damped Ly α Systems in BOSS

Energy Technology Data Exchange (ETDEWEB)

Mas-Ribas, Lluís [Institute of Theoretical Astrophysics, University of Oslo, Postboks 1029, NO-0315 Oslo (Norway); Miralda-Escudé, Jordi; Pérez-Ràfols, Ignasi; Arinyo-i-Prats, Andreu [Institut de Ciències del Cosmos, Universitat de Barcelona (UB-IEEC), Barcelona E-08028, Catalonia (Spain); Noterdaeme, Pasquier; Petitjean, Patrick [Institut d’Astrophysique de Paris, UPMC and CNRS, UMR7095 98bis Boulevard Arago, F-75014—Paris (France); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); York, Donald G. [Department of Astronomy and Astrophysics and the Enrico Fermi Institute, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Ge, Jian, E-mail: l.m.ribas@astro.uio.no [Department of Astronomy, University of Florida, Bryant Space Science Center, Gainesville, FL 32611-2055 (United States)

2017-09-01

We study the mean absorption spectrum of the Damped Ly α (DLA) population at z ∼ 2.6 by stacking normalized, rest-frame-shifted spectra of ∼27,000 DLA systems from the DR12 of the Baryon Oscillation Spectroscopic Survey (BOSS)/SDSS-III. We measure the equivalent widths of 50 individual metal absorption lines in five intervals of DLA hydrogen column density, five intervals of DLA redshift, and overall mean equivalent widths for an additional 13 absorption features from groups of strongly blended lines. The mean equivalent width of low-ionization lines increases with N {sub H} {sub i}, whereas for high-ionization lines the increase is much weaker. The mean metal line equivalent widths decrease by a factor ∼1.1–1.5 from z ∼ 2.1 to z ∼ 3.5, with small or no differences between low- and high-ionization species. We develop a theoretical model, inspired by the presence of multiple absorption components observed in high-resolution spectra, to infer mean metal column densities from the equivalent widths of partially saturated metal lines. We apply this model to 14 low-ionization species and to Al iii, S iii, Si iii, C iv, Si iv, N v, and O vi. We use an approximate derivation for separating the equivalent width contributions of several lines to blended absorption features, and infer mean equivalent widths and column densities from lines of the additional species N i, Zn ii, C ii*, Fe iii, and S iv. Several of these mean column densities of metal lines in DLAs are obtained for the first time; their values generally agree with measurements of individual DLAs from high-resolution, high signal-to-noise ratio spectra when they are available.

Time-dependent H-like and He-like Al lines produced by ultra-short pulse laser

Energy Technology Data Exchange (ETDEWEB)

Kato, Takako; Kato, Masatoshi [National Inst. for Fusion Science, Nagoya (Japan); Shepherd, R; Young, B; More, R; Osterheld, Al

1998-03-01

We have performed numerical modeling of time-resolved x-ray spectra from thin foil targets heated by the LLNL Ultra-short pulse (USP) laser. The targets were aluminum foils of thickness ranging from 250 A to 1250 A, heated with 120 fsec pulses of 400 nm light from the USP laser. The laser energy was approximately 0.2 Joules, focused to a 3 micron spot size for a peak intensity near 2 x 10{sup 19} W/cm{sup 2}. Ly{alpha} and He{alpha} lines were recorded using a 900 fsec x-ray streak camera. We calculate the effective ionization, recombination and emission rate coefficients including density effects for H-like and He-like aluminum ions using a collisional radiative model. We calculate time-dependent ion abundances using these effective ionization and recombination rate coefficients. The time-dependent electron temperature and density used in the calculation are based on an analytical model for the hydrodynamic expansion of the target foils. During the laser pulse the target is ionized. After the laser heating stops, the plasma begins to recombine. Using the calculated time dependent ion abundances and the effective emission rate coefficients, we calculate the time dependent Ly{alpha} and He{alpha} lines. The calculations reproduce the main qualitative features of the experimental spectra. (author)

STACKED REST-FRAME ULTRAVIOLET SPECTRA OF Lyα-EMITTING AND CONTINUUM-SELECTED GALAXIES AT 2 < z < 3.5

International Nuclear Information System (INIS)

Berry, Michael; Gawiser, Eric; Guaita, Lucia; Padilla, Nelson; Francke, Harold; Treister, Ezequiel; Blanc, Guillermo A.; Ciardullo, Robin; Gronwall, Caryl

2012-01-01

We present properties of individual and composite rest-UV spectra of continuum- and narrowband-selected star-forming galaxies (SFGs) at a redshift of 2 Lyα > 20 Å, the canonical limit to be classified as an Lyα-emitting galaxy. We divide our data set into subsamples based on properties that we are able to measure for each individual galaxy: Lyα equivalent width, rest-frame UV colors, and redshift. Among our subsample of galaxies with R Lyα > 20 Å have bluer UV continua, weaker low-ionization interstellar absorption lines, weaker C IV absorption, and stronger Si II* nebular emission than those with W Lyα –1 between Lyα emission and low-ionization absorption, which does not vary substantially among any of our subsamples. We find that the interstellar component, as opposed to the stellar component, dominates the high-ionization absorption line profiles. We find that the low- and high-ionization Si ionization states have similar kinematic properties, yet the low-ionization absorption is correlated with Lyα emission and the high-ionization absorption is not. These trends are consistent with outflowing neutral gas being in the form of neutral clouds embedded in ionized gas as previously suggested by Steidel et al. Moreover, our galaxies with bluer UV colors have stronger Lyα emission, weaker low-ionization absorption, and more prominent nebular emission line profiles. From a redshift of 2.7 Lyα Lyα > 20 Å exhibit weaker Lyα emission at lower redshifts, although we caution that this could be caused by spectroscopic confirmation of low Lyα equivalent width galaxies being harder at z ∼ 3 than z ∼ 2.

Spectroscopy of z ~ 6 i-Dropout Galaxies: Frequency of Lyα Emission and the Sizes of Lyα-emitting Galaxies1,

Science.gov (United States)

Dow-Hygelund, C. C.; Holden, B. P.; Bouwens, R. J.; Illingworth, G. D.; van der Wel, A.; Franx, M.; van Dokkum, P. G.; Ford, H.; Rosati, P.; Magee, D.; Zirm, A.

2007-05-01

We report on deep spectroscopy, using LRIS on Keck I and FORS2 on the VLT, of a sample of 22 candidate z~6 Lyman break galaxies (LBGs) selected by the i775-z850>1.3 dropout criterion. Redshifts could be measured for eight objects. These redshifts are all in the range z=5.5-6.1, confirming the efficiency of the i775-z850 color selection technique. Six of the confirmed galaxies show Lyα emission. Assuming that the 14 objects without redshifts are z~6 LBGs that lack detectable Lyα emission lines, we infer that the fraction of Lyα-emitting LBGs with Lyα equivalent widths greater than 20 Å among z~6 LBGs is ~30%, similar to that found at z~3. Every Lyα-emitting object in our sample is compact, with half-light radii rhldropout sample (332 candidate z~6 objects). We can reject the hypothesis that the Lyα-emitting population is a subset of the rest of the z~6 LBG population at >97% confidence. We speculate that the small sizes of the Lyα-emitting LBGs are due to these objects being less massive than other LBGs at z~6. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 7817, 9270, 9301, 9583, and 9803. Based on observations collected at the European Southern Observatory, Paranal, Chile (LP166.A-0701 and 169.A-045).

Far-ultraviolet and optical spectrophotometry of X-ray selected Seyfert galaxies

International Nuclear Information System (INIS)

Clarke, J.T.; Bowyer, S.; Grewing, M.; California Univ., Berkeley; Tuebingen Universitaet, West Germany)

1986-01-01

Five X-ray selected Seyfert galaxies were examined via near-simultaneous far-ultraviolet and optical spectrophotometry in an effort to test models for excitation of emission lines by X-ray and ultraviolet continuum photoionization. The observed Ly-alpha/H-beta ratio in the present sample averages 22, with an increase found toward the high-velocity wings of the H lines in the spectrum of at least one of the Seyfert I nuclei. It is suggested that Seyfert galaxies with the most high-velocity gas exhibit the highest Ly-alpha/H-beta ratios at all velocities in the line profiles, and that sometimes this ratio may be highest for the highest velocity material in the broad-line clouds. Since broad-lined objects are least affected by Ly-alpha trapping effects, they have Ly-alpha/H-beta ratios much closer to those predicted by early photoionization calculations. 21 references

The Lyα reference sample. I. Survey outline and first results for Markarian 259

International Nuclear Information System (INIS)

Östlin, Göran; Hayes, Matthew; Duval, Florent; Sandberg, Andreas; Rivera-Thorsen, Thøger; Marquart, Thomas; Adamo, Angela; Melinder, Jens; Guaita, Lucia; Micheva, Genoveva; Orlitová, Ivana; Atek, Hakim; Cannon, John M.; Pardy, Stephen A.; Gruyters, Pieter; Herenz, Edmund Christian; Kunth, Daniel; Laursen, Peter; Mas-Hesse, J. Miguel; Otí-Floranes, Héctor

2014-01-01

The Lyα Reference Sample (LARS) is a substantial program with the Hubble Space Telescope (HST) that provides a sample of local universe laboratory galaxies in which to study the detailed astrophysics of the visibility and strength of the Lyαline of neutral hydrogen. Lyα is the dominant spectral line in use for characterizing high-redshift (z) galaxies. This paper presents an overview of the survey, its selection function, and HST imaging observations. The sample was selected from the combined GALEX+Sloan Digital Sky Survey catalog at z = 0.028-0.19, in order to allow Lyα to be captured with combinations of long-pass filters in the Solar Blind Channel (SBC) of the Advanced Camera for Surveys (ACS) onboard HST. In addition, LARS utilizes Hα and Hβ narrowband and u, b, i broadband imaging with ACS and the Wide Field Camera 3 (WFC3). In order to study galaxies in which large numbers of Lyα photons are produced (whether or not they escape), we demanded an Hα equivalent width W(Hα) ≥100 Å. The final sample of 14 galaxies covers far-UV (FUV, λ ∼ 1500 Å) luminosities that overlap with those of high-z Lyα emitters (LAEs) and Lyman break galaxies (LBGs), making LARS a valid comparison sample. We present the reduction steps used to obtain the Lyα images, including our LARS eXtraction software (LaXs), which utilizes pixel-by-pixel spectral synthesis fitting of the energy distribution to determine and subtract the continuum at Lyα. We demonstrate that the use of SBC long-pass-filter combinations increase the signal-to-noise ratio by an order of magnitude compared to the nominal Lyα filter available in SBC. To exemplify the science potential of LARS, we also present some first results for a single galaxy, Mrk 259 (LARS #1). This irregular galaxy shows bright and extended (indicative of resonance scattering) but strongly asymmetric Lyα emission. Spectroscopy from the Cosmic Origins Spectrograph on board HST centered on the brightest UV knot shows a moderate

The Lyα reference sample. I. Survey outline and first results for Markarian 259

Energy Technology Data Exchange (ETDEWEB)

Östlin, Göran; Hayes, Matthew; Duval, Florent; Sandberg, Andreas; Rivera-Thorsen, Thøger; Marquart, Thomas; Adamo, Angela; Melinder, Jens; Guaita, Lucia; Micheva, Genoveva [Department of Astronomy, Stockholm University, Oscar Klein Centre, AlbaNova, Stockholm SE-106 91 (Sweden); Orlitová, Ivana [Observatoire de Genève, Université de Genève, Chemin des Maillettes 51, 1290 Versoix (Switzerland); Atek, Hakim [Laboratoire d' Astrophysique, Ecole Polytechnique Fédérale de Lausanne, Observatoire de Sauverny, CH-1290 Versoix (Switzerland); Cannon, John M.; Pardy, Stephen A. [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Gruyters, Pieter [Department of Physics and Astronomy, Division of Astronomy and Space Physics, Uppsala University, Box 516, 75120 Uppsala (Sweden); Herenz, Edmund Christian [Leibniz-Institute for Astrophysics Potsdam (AIP), innoFSPEC, An der Sternwarte 16, D-14482 Potsdam (Germany); Kunth, Daniel [Institut d' Astrophysique Paris, 98bis Bd Arago, F-75014 Paris (France); Laursen, Peter [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Mas-Hesse, J. Miguel [Centro de Astrobiologa (CSIC-INTA), Departamento de Astrofsica, POB 78, E-28691, Villanueva de la Cañada (Spain); Otí-Floranes, Héctor [Instituto de Astronoma, Universidad Nacional Autnoma de Mxico, Apdo. Postal 106, Ensenada B. C. 22800 (Mexico); and others

2014-12-10

The Lyα Reference Sample (LARS) is a substantial program with the Hubble Space Telescope (HST) that provides a sample of local universe laboratory galaxies in which to study the detailed astrophysics of the visibility and strength of the Lyαline of neutral hydrogen. Lyα is the dominant spectral line in use for characterizing high-redshift (z) galaxies. This paper presents an overview of the survey, its selection function, and HST imaging observations. The sample was selected from the combined GALEX+Sloan Digital Sky Survey catalog at z = 0.028-0.19, in order to allow Lyα to be captured with combinations of long-pass filters in the Solar Blind Channel (SBC) of the Advanced Camera for Surveys (ACS) onboard HST. In addition, LARS utilizes Hα and Hβ narrowband and u, b, i broadband imaging with ACS and the Wide Field Camera 3 (WFC3). In order to study galaxies in which large numbers of Lyα photons are produced (whether or not they escape), we demanded an Hα equivalent width W(Hα) ≥100 Å. The final sample of 14 galaxies covers far-UV (FUV, λ ∼ 1500 Å) luminosities that overlap with those of high-z Lyα emitters (LAEs) and Lyman break galaxies (LBGs), making LARS a valid comparison sample. We present the reduction steps used to obtain the Lyα images, including our LARS eXtraction software (LaXs), which utilizes pixel-by-pixel spectral synthesis fitting of the energy distribution to determine and subtract the continuum at Lyα. We demonstrate that the use of SBC long-pass-filter combinations increase the signal-to-noise ratio by an order of magnitude compared to the nominal Lyα filter available in SBC. To exemplify the science potential of LARS, we also present some first results for a single galaxy, Mrk 259 (LARS #1). This irregular galaxy shows bright and extended (indicative of resonance scattering) but strongly asymmetric Lyα emission. Spectroscopy from the Cosmic Origins Spectrograph on board HST centered on the brightest UV knot shows a moderate

Constraints on neutrino masses from Lyman-alpha forest power spectrum with BOSS and XQ-100

Energy Technology Data Exchange (ETDEWEB)

Yèche, Christophe; Palanque-Delabrouille, Nathalie; Baur, Julien; Bourboux, Hélion du Mas des, E-mail: christophe.yeche@cea.fr, E-mail: nathalie.palanque-delabrouille@cea.fr, E-mail: julien.baur@cea.fr, E-mail: helion.du-mas-des-bourboux@cea.fr [CEA, Centre de Saclay, IRFU/SPP, F-91191 Gif-sur-Yvette (France)

2017-06-01

We present constraints on masses of active and sterile neutrinos in the context of the ΛCDMν and ΛWDM models, respectively. We use the one-dimensional Lyα-forest power spectrum from the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey (SDSS-III) measured by Palanque-Delabrouille et al. [1], and from the VLT/XSHOOTER legacy survey (XQ-100). In this paper, we present our own measurement of the publicly released XQ-100 quasar spectra, focusing in particular on an improved determination of the spectrograph resolution that allows us to push to smaller scales than the public release and reach k -modes of 0.070 s km{sup −1}. We compare the obtained 1D Lyα flux power spectrum to the one measured by Irsic et al. [2] to k -modes of 0.057 s km{sup −1}. Fitting Lyα data alone leads to cosmological parameters in excellent agreement with the values derived independently from Planck 2015 Cosmic Microwave Background (CMB) data. Combining BOSS and XQ-100 Lyα power spectra, we constrain the sum of neutrino masses to ∑ m {sub ν} < 0.8 eV (95% C.L.) including all identified sources of systematic uncertainties. With the addition of CMB data, this bound is tightened to ∑ m {sub ν} < 0.14 eV (95% C.L.). With their sensitivity to small scales, Lyα data are ideal to constrain ΛWDM models. Using XQ-100 alone, we issue lower bounds on pure dark matter particles: m {sub X} ∼> 2.08 : keV (95% C.L.) for early decoupled thermal relics, and m {sub s} ∼> 10.2 : keV (95% C.L.) for non-resonantly produced right-handed neutrinos. Combining the 1D Lyα-forest power spectrum measured by BOSS and XQ-100, we improve the two bounds to m {sub X} ∼> 4.17 : keV and m {sub s} ∼> 25.0 : keV (95% C.L.), slightly more constraining than what was achieved in Baur et al. 2015 [3] with BOSS data alone. The 3 σ bound shows a more significant improvement, increasing from m {sub X} ∼> 2.74 : keV for BOSS alone to m {sub X} ∼> 3.10 : keV for the combined BOSS

Physical properties of z ~ 4 LBGs: differences between galaxies with and without Lyα emission

Science.gov (United States)

Pentericci, L.; Grazian, A.; Fontana, A.; Salimbeni, S.; Santini, P.; de Santis, C.; Gallozzi, S.; Giallongo, E.

2007-08-01

Aims:We analysed the physical properties of z ˜4 Lyman Break Galaxies observed in the GOODS-S survey, in order to investigate possible differences between galaxies where the Lyα is present in emission, and those where the line is absent or in absorption. Methods: The objects were selected from their optical color and then spectroscopically confirmed by Vanzella et al. (2005). From the public spectra we assessed the nature of the Lyα emission and divided the sample into galaxies with Lyα in emission and objects without a Lyα line (i.e. either absent or in absorption). We then used complete photometry, from U band to mid-infrared from the GOODS-MUSIC database, to study the observational properties of the galaxies, such as UV spectral slopes and optical to mid-infrared colors, and the possible differences between the two samples. Lastly, we used standard spectral fitting techniques to determine the physical properties of the galaxies, such as total stellar mass, stellar ages and so on, and again we looked at the possible differences between the two samples. Results: Our results indicate that LBG with Lyα in emission are on average a much younger and less massive population than the LBGs without Lyα emission. Both populations are forming stars very actively and are relatively dust free, although those with line emission seem to be even less dusty on average. We briefly discuss these results in the context of recent models for the evolution of Lyman break galaxies and Lyα emitters.

Impact of Massive Neutrinos and Dark Radiation on the High-redshift Cosmic Web. I. Lyα Forest Observables

Science.gov (United States)

Rossi, Graziano

2017-11-01

With upcoming high-quality data from surveys such as the Extended Baryon Oscillation Spectroscopic Survey or the Dark Energy Spectroscopic Instrument, improving the theoretical modeling and gaining a deeper understanding of the effects of neutrinos and dark radiation on structure formation at small scales are necessary, to obtain robust constraints free from systematic biases. Using a novel suite of hydrodynamical simulations that incorporate dark matter, baryons, massive neutrinos, and dark radiation, we present a detailed study of their impact on Lyα forest observables. In particular, we accurately measure the tomographic evolution of the shape and amplitude of the small-scale matter and flux power spectra and search for unique signatures along with preferred scales where a neutrino mass detection may be feasible. We then investigate the thermal state of the intergalactic medium (IGM) through the temperature-density relation. Our findings suggest that at k˜ 5 h {{Mpc}}-1 the suppression on the matter power spectrum induced by \\sum {m}ν =0.1 {eV} neutrinos can reach ˜ 4 % at z˜ 3 when compared to a massless neutrino cosmology, and ˜ 10 % if a massless sterile neutrino is included; surprisingly, we also find good agreement (˜ 2 % ) with some analytic predictions. For the 1D flux power spectrum {P}{ F }1{{D}}, the highest response to free-streaming effects is achieved at k˜ 0.005 {[{km}/{{s}}]}-1 when \\sum {m}ν =0.1 {eV}; this k-limit falls in the Lyα forest regime, making the small-scale {P}{ F }1{{D}} an excellent probe for detecting neutrino and dark radiation imprints. Our results indicate that the IGM at z˜ 3 provides the best sensitivity to active and sterile neutrinos.

DIFFUSE Lyα EMITTING HALOS: A GENERIC PROPERTY OF HIGH-REDSHIFT STAR-FORMING GALAXIES

International Nuclear Information System (INIS)

Steidel, Charles C.; Bogosavljevic, Milan; Shapley, Alice E.; Kollmeier, Juna A.; Reddy, Naveen A.; Erb, Dawn K.; Pettini, Max

2011-01-01

Using a sample of 92 UV continuum-selected, spectroscopically identified galaxies with (z) = 2.65, all of which have been imaged in the Lyα line with extremely deep narrow-band imaging, we examine galaxy Lyα emission profiles to very faint surface brightness limits. The galaxy sample is representative of spectroscopic samples of Lyman break galaxies (LBGs) at similar redshifts in terms of apparent magnitude, UV luminosity, inferred extinction, and star formation rate and was assembled without regard to Lyα emission properties. Approximately 45% (55%) of the galaxy spectra have Lyα appearing in net absorption (emission), with ≅ 20% satisfying commonly used criteria for the identification of 'Lyα emitters' (LAEs; W 0 (Lyα) ≥ 20 A). We use extremely deep stacks of rest-UV continuum and continuum-subtracted Lyα images to show that all sub-samples exhibit diffuse Lyα emission to radii of at least 10'' (∼80 physical kpc). The characteristic exponential scale lengths for Lyα line emission exceed that of the λ 0 = 1220 A UV continuum light by factors of ∼5-10. The surface brightness profiles of Lyα emission are strongly suppressed relative to the UV continuum light in the inner few kpc, by amounts that are tightly correlated with the galaxies' observed spectral morphology; however, all galaxy sub-subsamples, including that of galaxies for which Lyα appears in net absorption in the spectra, exhibit qualitatively similar diffuse Lyα emission halos. Accounting for the extended Lyα emission halos, which generally would not be detected in the slit spectra of individual objects or with typical narrow-band Lyα imaging, increases the total Lyα flux (and rest equivalent width W 0 (Lyα)) by an average factor of ∼5, and by a much larger factor for the 80% of LBGs not classified as LAEs. We argue that most, if not all, of the observed Lyα emission in the diffuse halos originates in the galaxy H II regions but is scattered in our direction by H I gas in the

A DEEP NARROWBAND IMAGING SEARCH FOR C iv AND He ii EMISSION FROM Lyα BLOBS

International Nuclear Information System (INIS)

Battaia, Fabrizio Arrigoni; Yang, Yujin; Hennawi, Joseph F.; Prochaska, J. Xavier; Matsuda, Yuichi; Yamada, Toru; Hayashino, Tomoki

2015-01-01

We conduct a deep narrowband imaging survey of 13 Lyα blobs (LABs) located in the SSA22 proto-cluster at z ∼ 3.1 in the C iv and He ii emission lines in an effort to constrain the physical process powering the Lyα emission in LABs. Our observations probe down to unprecedented surface brightness (SB) limits of (2.1–3.4) × 10 −18 erg s −1 cm −2 arcsec −2 per 1 arcsec 2 aperture (5σ) for the He ii λ1640 and C iv λ1549 lines, respectively. We do not detect extended He ii and C iv emission in any of the LABs, placing strong upper limits on the He ii/Lyα and C iv/Lyα line ratios, of 0.11 and 0.16, for the brightest two LABs in the field. We conduct detailed photoionization modeling of the expected line ratios and find that, although our data constitute the deepest ever observations of these lines, they are still not deep enough to rule out a scenario where the Lyα emission is powered by the ionizing radiation from an obscured active galactic nucleus. Our models can accommodate He ii/Lyα and C iv/Lyα ratios as low as ≃0.05 and ≃0.07, respectively, implying that one needs to reach SB as low as (1–1.5) × 10 −18 erg s −1 cm −2 arcsec −2  (at 5σ) in order to rule out a photoionization scenario. These depths will be achievable with the new generation of image-slicing integral field units such as the Multi Unit Spectroscopic Explorer (MUSE) on VLT and the Keck Cosmic Web Imager (KCWI). We also model the expected He ii/Lyα and C iv/Lyα in a different scenario, where Lyα emission is powered by shocks generated in a large-scale superwind, but find that our observational constraints can only be met for shock velocities v s ≳ 250 km s −1 , which appear to be in conflict with recent observations of quiescent kinematics in LABs

Ultraviolet photometry from the orbiting astronomical observatory. XVI - The stellar Lyman-alpha absorption line

Science.gov (United States)

Savage, B. D.; Panek, R. J.

1974-01-01

The stellar Lyman-alpha line at 1216 A was observed in 29 lightly reddened stars of spectral type B2.5 to B9 by a far-UV spectrophotometer on OAO-2. The equivalent widths obtained range from 15 A at type B2.5 to 65 A at type B8; in the late-B stars, the L-alpha line removes 2 to 3% of the total stellar flux. In this sampling, the strength of the L-alpha line correlates well with measures of the Balmer discontinuity and Balmer line strengths; luminosity classification does not seem to affect the line strength. The observed line widths also agree with the predictions of Mihala's grid of non-LTE model atmospheres. In some cases, the L-alpha line influences the interstellar column densities reported in the interstellar OAO-2 L-alpha survey. Hence, these data toward lightly reddened B2 and B1.5 stars should be regarded as upper limits only.

A submillimeter galaxy illuminating its circumgalactic medium: Lyα scattering in a cold, clumpy outflow

Energy Technology Data Exchange (ETDEWEB)

Geach, J. E.; Coppin, K. E. K.; Smith, D. J. B. [Center for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Bower, R. G.; Alexander, D. M.; Swinbank, A. M. [Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Blain, A. W. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Bremer, M. N. [School of Physics, HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Chapin, E. L. [XMM SOC, ESAC, Apartado 78, E-28691 Villanueva de la Canada, Madrid (Spain); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University Halifax, NS B3H 3J5 (Canada); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Dunlop, J. S.; Koprowski, M. P.; Michałowski, M. J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Farrah, D. [Virginia Polytechnic Institute and State University Department of Physics, MC 0435, 910 Drillfield Drive, Blacksburg, VA 24061 (United States); Jenness, T. [Joint Astronomy Centre, 660 North A' ohoku Place University Park, Hilo, HI 96720 (United States); Robson, E. I. [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Scott, D. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Spaans, M. [Kapteyn Institute, University of Groningen, PO Box 800, 9700 AV Groningen (Netherlands); Van der Werf, P., E-mail: j.geach@herts.ac.uk [Leiden Observatory, Leiden University, PO box 9513, 2300 RA Leiden (Netherlands)

2014-09-20

We report the detection at 850 μm of the central source in SSA22-LAB1, the archetypal 'Lyman-α Blob' (LAB), a 100 kpc scale radio-quiet emission-line nebula at z = 3.1. The flux density of the source, S {sub 850} = 4.6 ± 1.1 mJy, implies the presence of a galaxy or group of galaxies with a total luminosity of L {sub IR} ≈ 10{sup 12} L {sub ☉}. The position of an active source at the center of a ∼50 kpc radius ring of linearly polarized Lyα emission detected by Hayes et al. suggests that the central source is leaking Lyα photons preferentially in the plane of the sky, which undergo scattering in H I clouds at a large galactocentric radius. The Lyα morphology around the submillimeter detection is reminiscent of a biconical outflow, and the average Lyα line profiles of the two 'lobes' are dominated by a red peak, which is expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evidence that the central active galaxy (or galaxies) is responsible for a large fraction of the extended Lyα emission and morphology. Less clear is the history of the cold gas in the circumgalactic medium being traced by Lyα: is it mainly pristine material accreting into the halo that has not yet been processed through an interstellar medium (ISM), now being blown back as it encounters an outflow, or does it mainly comprise gas that has been swept-up within the ISM and expelled from the galaxy?.

PREDICTING Lyα AND Mg II FLUXES FROM K AND M DWARFS USING GALAXY EVOLUTION EXPLORER ULTRAVIOLET PHOTOMETRY

International Nuclear Information System (INIS)

Shkolnik, Evgenya L.; Rolph, Kristina A.; Peacock, Sarah; Barman, Travis S.

2014-01-01

A star's ultraviolet (UV) emission can greatly affect the atmospheric chemistry and physical properties of closely orbiting planets with the potential for severe mass loss. In particular, the Lyα emission line at 1216 Å, which dominates the far-ultraviolet (FUV) spectrum, is a major source of photodissociation of important atmospheric molecules such as water and methane. The intrinsic flux of Lyα, however, cannot be directly measured due to the absorption of neutral hydrogen in the interstellar medium and contamination by geocoronal emission. To date, reconstruction of the intrinsic Lyα line based on Hubble Space Telescope spectra has been accomplished for 46 FGKM nearby stars, 28 of which have also been observed by the Galaxy Evolution Explorer (GALEX). Our investigation provides a correlation between published intrinsic Lyα and GALEX far- and near-ultraviolet (NUV) chromospheric fluxes for K and M stars. The negative correlations between the ratio of the Lyα to the GALEX fluxes reveal how the relative strength of Lyα compared to the broadband fluxes weakens as the FUV and NUV excess flux increase. We also correlate GALEX fluxes with the strong NUV Mg II h+k spectral emission lines formed at lower chromospheric temperatures than Lyα. The reported correlations provide estimates of intrinsic Lyα and Mg II fluxes for the thousands of K and M stars in the archived GALEX all-sky surveys. These will constrain new stellar upper atmosphere models for cool stars and provide realistic inputs to models describing exoplanetary photochemistry and atmospheric evolution in the absence of UV spectroscopy

A DEEP NARROWBAND IMAGING SEARCH FOR C iv AND He ii EMISSION FROM Lyα BLOBS

Energy Technology Data Exchange (ETDEWEB)

Battaia, Fabrizio Arrigoni; Yang, Yujin; Hennawi, Joseph F. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Prochaska, J. Xavier [Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, California 95064 (United States); Matsuda, Yuichi [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Yamada, Toru [Astronomical Institute, Tohoku University, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Hayashino, Tomoki, E-mail: arrigoni@mpia.de [Research Center for Neutrino Science, Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan)

2015-05-01

We conduct a deep narrowband imaging survey of 13 Lyα blobs (LABs) located in the SSA22 proto-cluster at z ∼ 3.1 in the C iv and He ii emission lines in an effort to constrain the physical process powering the Lyα emission in LABs. Our observations probe down to unprecedented surface brightness (SB) limits of (2.1–3.4) × 10{sup −18} erg s{sup −1} cm{sup −2} arcsec{sup −2} per 1 arcsec{sup 2} aperture (5σ) for the He ii λ1640 and C iv λ1549 lines, respectively. We do not detect extended He ii and C iv emission in any of the LABs, placing strong upper limits on the He ii/Lyα and C iv/Lyα line ratios, of 0.11 and 0.16, for the brightest two LABs in the field. We conduct detailed photoionization modeling of the expected line ratios and find that, although our data constitute the deepest ever observations of these lines, they are still not deep enough to rule out a scenario where the Lyα emission is powered by the ionizing radiation from an obscured active galactic nucleus. Our models can accommodate He ii/Lyα and C iv/Lyα ratios as low as ≃0.05 and ≃0.07, respectively, implying that one needs to reach SB as low as (1–1.5) × 10{sup −18} erg s{sup −1} cm{sup −2} arcsec{sup −2} (at 5σ) in order to rule out a photoionization scenario. These depths will be achievable with the new generation of image-slicing integral field units such as the Multi Unit Spectroscopic Explorer (MUSE) on VLT and the Keck Cosmic Web Imager (KCWI). We also model the expected He ii/Lyα and C iv/Lyα in a different scenario, where Lyα emission is powered by shocks generated in a large-scale superwind, but find that our observational constraints can only be met for shock velocities v{sub s} ≳ 250 km s{sup −1}, which appear to be in conflict with recent observations of quiescent kinematics in LABs.

The Ca II resonance lines in M dwarf stars without H-alpha emission

Energy Technology Data Exchange (ETDEWEB)

Giampapa, M.S.; Cram, L.E.; Wild, W.J. (National Solar Observatory, Tucson, AZ (USA) Sydney Univ. (Australia) Arizona Univ., Tucson (USA))

1989-10-01

Spectra of the Ca II H and K lines in a sample of 31 M dwarf stars without H-alpha emission are used to calculate chromospheric K line radiative losses, F(k), and to study the joint response of Ca II K and H-alpha to chromospheric heating in dwarf M stars. It is suggested that the poor correlation found in the equivalent width - log F(K) diagram may be due either to radial segregation of the H-alpha and K line forming regions or to lateral inhomogeneities in the chromospheres. The results confirm the existence of dM stars with weak H-alpha absorption and K line emission only slightly weaker than that of the dMe stars, and show that dM stars with weak H-alpha but kinematics and metallicities representative of the young disk population belong to a class characterized by a comparatively high degree of chromospheric activity. 32 refs.

DISCOVERY OF A DAMPED Lyα ABSORBER AT z = 3.3 ALONG A GALAXY SIGHT-LINE IN THE SSA22 FIELD

Energy Technology Data Exchange (ETDEWEB)

Mawatari, K.; Inoue, A. K. [College of General Education, Osaka Sangyo University, 3-1-1, Nakagaito, Daito, Osaka, 574-8530 (Japan); Kousai, K.; Hayashino, T. [Research Center for Neutrino Science, General School of Science, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578 (Japan); Cooke, R.; Prochaska, J. X. [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Yamada, T. [Astronomical Institute, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578 (Japan); Matsuda, Y., E-mail: mawatari@las.osaka-sandai.ac.jp [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan)

2016-02-01

Using galaxies as background light sources to map the Lyα absorption lines is a novel approach to study Damped Lyα Absorbers (DLAs). We report the discovery of an intervening z = 3.335 ± 0.007 DLA along a galaxy sight-line identified among 80 Lyman Break Galaxy (LBG) spectra obtained with our Very Large Telescope/Visible Multi-Object Spectrograph survey in the SSA22 field. The measured DLA neutral hydrogen (H i) column density is log(N{sub H} {sub i}/cm{sup −2}) = 21.68 ± 0.17. The DLA covering fraction over the extended background LBG is >70% (2σ), yielding a conservative constraint on the DLA area of ≳1 kpc{sup 2}. Our search for a counterpart galaxy hosting this DLA concludes that there is no counterpart galaxy with star formation rate larger than a few M{sub ⊙} yr{sup −1}, ruling out an unobscured violent star formation in the DLA gas cloud. We also rule out the possibility that the host galaxy of the DLA is a passive galaxy with M{sub *} ≳ 5 × 10{sup 10}M{sub ⊙} or a heavily dust-obscured galaxy with E(B − V) ≳ 2. The DLA may coincide with a large-scale overdensity of the spectroscopic LBGs. The occurrence rate of the DLA is compatible with that of DLAs found in QSO sight-lines.

On the lack of correlation between Mg II 2796, 2803 Å and Lyα emission in lensed star-forming galaxies

Energy Technology Data Exchange (ETDEWEB)

Rigby, J. R. [Astrophysics Science Division, Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Bayliss, M. B. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Gladders, M. D. [Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Avenue, Chicago, IL 60637 (United States); Sharon, K. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Wuyts, E. [Max Plank Institute for Extraterrestrial Physics, Giessenbachstrasse 1, D-85748 Garching (Germany); Dahle, H. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway)

2014-07-20

We examine the Mg II 2796, 2803 Å, Lyα, and nebular line emission in five bright star-forming galaxies at 1.66 < z < 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 Lyα 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 100-200 km s{sup –1}. When present, Lyα is even more redshifted. The reddest components of Mg II and Lyα emission have tails to 500-600 km s{sup –1}, implying a strong outflow. The lack of correlation in the Mg II and Lyα 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.

Deep Submillimeter and Radio Observations in the SSA22 Field. I. Powering Sources and the Lyα Escape Fraction of Lyα Blobs

Science.gov (United States)

Ao, Y.; Matsuda, Y.; Henkel, C.; Iono, D.; Alexander, D. M.; Chapman, S. C.; Geach, J.; Hatsukade, B.; Hayes, M.; Hine, N. K.; Kato, Y.; Kawabe, R.; Kohno, K.; Kubo, M.; Lehnert, M.; Malkan, M.; Menten, K. M.; Nagao, T.; Norris, R. P.; Ouchi, M.; Saito, T.; Tamura, Y.; Taniguchi, Y.; Umehata, H.; Weiss, A.

2017-12-01

We study the heating mechanisms and Lyα escape fractions of 35 Lyα blobs (LABs) at z ≈ 3.1 in the SSA22 field. Dust continuum sources have been identified in 11 of the 35 LABs, all with star formation rates (SFRs) above 100 M ⊙ yr-1. Likely radio counterparts are detected in 9 out of 29 investigated LABs. The detection of submillimeter dust emission is more linked to the physical size of the Lyα emission than to the Lyα luminosities of the LABs. A radio excess in the submillimeter/radio-detected LABs is common, hinting at the presence of active galactic nuclei. Most radio sources without X-ray counterparts are located at the centers of the LABs. However, all X-ray counterparts avoid the central regions. This may be explained by absorption due to exceptionally large column densities along the line-of-sight or by LAB morphologies, which are highly orientation dependent. The median Lyα escape fraction is about 3% among the submillimeter-detected LABs, which is lower than a lower limit of 11% for the submillimeter-undetected LABs. We suspect that the large difference is due to the high dust attenuation supported by the large SFRs, the dense large-scale environment as well as large uncertainties in the extinction corrections required to apply when interpreting optical data.

A Faint Flux-limited Ly α Emitter Sample at z ∼ 0.3

Energy Technology Data Exchange (ETDEWEB)

Wold, Isak G. B.; Finkelstein, Steven L. [Department of Astronomy, The University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712 (United States); Barger, Amy J.; Rosenwasser, Benjamin [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Cowie, Lennox L., E-mail: wold@astro.as.utexas.edu [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

2017-10-20

We present a flux-limited sample of z ∼ 0.3 Ly α emitters (LAEs) from Galaxy Evolution Explorer ( GALEX ) grism spectroscopic data. The published GALEX z ∼ 0.3 LAE sample is pre-selected from continuum-bright objects and thus is biased against high equivalent width (EW) LAEs. We remove this continuum pre-selection and compute the EW distribution and the luminosity function of the Ly α emission line directly from our sample. We examine the evolution of these quantities from z ∼ 0.3 to 2.2 and find that the EW distribution shows little evidence for evolution over this redshift range. As shown by previous studies, the Ly α luminosity density from star-forming (SF) galaxies declines rapidly with declining redshift. However, we find that the decline in Ly α luminosity density from z = 2.2 to z = 0.3 may simply mirror the decline seen in the H α luminosity density from z = 2.2 to z = 0.4, implying little change in the volumetric Ly α escape fraction. Finally, we show that the observed Ly α luminosity density from AGNs is comparable to the observed Ly α luminosity density from SF galaxies at z = 0.3. We suggest that this significant contribution from AGNs to the total observed Ly α luminosity density persists out to z ∼ 2.2.

Quercetin suppresses hypoxia-induced accumulation of hypoxia-inducible factor-1alpha (HIF-1alpha) through inhibiting protein synthesis.

Science.gov (United States)

Lee, Dae-Hee; Lee, Yong J

2008-10-01

Quercetin, a ubiquitous bioactive plant flavonoid, has been shown to inhibit the proliferation of cancer cells and induce the accumulation of hypoxia-inducible factor-1alpha (HIF-1alpha) in normoxia. In this study, under hypoxic conditions (1% O(2)), we examined the effect of quercetin on the intracellular level of HIF-1alpha and extracellular level of vascular endothelial growth factor (VEGF) in a variety of human cancer cell lines. Surprisingly, we observed that quercetin suppressed the HIF-1alpha accumulation during hypoxia in human prostate cancer LNCaP, colon cancer CX-1, and breast cancer SkBr3 cells. Quercetin treatment also significantly reduced hypoxia-induced secretion of VEGF. Suppression of HIF-1alpha accumulation during treatment with quercetin in hypoxia was not prevented by treatment with 26S proteasome inhibitor MG132 or PI3K inhibitor LY294002. Interestingly, hypoxia (1% O(2)) in the presence of 100 microM quercetin inhibited protein synthesis by 94% during incubation for 8 h. Significant quercetin concentration-dependent inhibition of protein synthesis and suppression of HIF-1alpha accumulation were observed under hypoxic conditions. Treatment with 100 microM cycloheximide, a protein synthesis inhibitor, replicated the effect of quercetin by inhibiting HIF-1alpha accumulation during hypoxia. These results suggest that suppression of HIF-1alpha accumulation during treatment with quercetin under hypoxic conditions is due to inhibition of protein synthesis. (c) 2008 Wiley-Liss, Inc.

The Lyα properties of faint galaxies at z ∼ 2-3 with systemic redshifts and velocity dispersions from Keck-MOSFIRE

Energy Technology Data Exchange (ETDEWEB)

Erb, Dawn K. [Center for Gravitation, Cosmology and Astrophysics, Department of Physics, University of Wisconsin Milwaukee, 1900 East Kenwood Boulevard, Milwaukee, WI 53211 (United States); Steidel, Charles C.; Trainor, Ryan F.; Strom, Allison L.; Konidaris, Nicholas P.; Matthews, Keith [Cahill Center for Astrophysics, California Institute of Technology, 1216 East California Boulevard, MS 249-17, Pasadena, CA 91125 (United States); Bogosavljević, Milan [Astronomical Observatory, Volgina 7, 11060 Belgrade (Serbia); Shapley, Alice E.; Nestor, Daniel B.; Mace, Gregory; McLean, Ian S. [Department of Physics and Astronomy, University of California, Los Angeles, 430 Portola Plaza, Los Angeles, CA 90095 (United States); Kulas, Kristin R. [NASA Ames Research Center, Bldg. 211, Room 112, Moffett Field, CA 94035-1000 (United States); Law, David R. [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); Rudie, Gwen C. [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Reddy, Naveen A. [Department of Physics and Astronomy, University of California, Riverside, 900 University Avenue, Riverside, CA 92521 (United States); Pettini, Max, E-mail: erbd@uwm.edu [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)

2014-11-01

We study the Lyα profiles of 36 spectroscopically detected Lyα-emitters (LAEs) at z ∼ 2-3, using Keck MOSFIRE to measure systemic redshifts and velocity dispersions from rest-frame optical nebular emission lines. The sample has a median optical magnitude R=26.0, and ranges from R≃23 to R>27, corresponding to rest-frame UV absolute magnitudes M {sub UV} ≅ –22 to M {sub UV} > –18.2. Dynamical masses range from M {sub dyn} < 1.3 × 10{sup 8} M {sub ☉} to M {sub dyn} = 6.8 × 10{sup 9} M {sub ☉}, with a median value of M {sub dyn} = 6.3 × 10{sup 8} M {sub ☉}. Thirty of the 36 Lyα emission lines are redshifted with respect to the systemic velocity with at least 1σ significance, and the velocity offset with respect to systemic Δv {sub Lyα} is correlated with the R-band magnitude, M {sub UV}, and the velocity dispersion measured from nebular emission lines with >3σ significance: brighter galaxies with larger velocity dispersions tend to have larger values of Δv {sub Lyα}. We also make use of a comparison sample of 122 UV-color-selected R<25.5 galaxies at z ∼ 2, all with Lyα emission and systemic redshifts measured from nebular emission lines. Using the combined LAE and comparison samples for a total of 158 individual galaxies, we find that Δv {sub Lyα} is anti-correlated with the Lyα equivalent width with 7σ significance. Our results are consistent with a scenario in which the Lyα profile is determined primarily by the properties of the gas near the systemic redshift; in such a scenario, the opacity to Lyα photons in lower mass galaxies may be reduced if large gaseous disks have not yet developed and if the gas is ionized by the harder spectrum of young, low metallicity stars.

The Lyman-alpha signature of the first galaxies

Science.gov (United States)

Smith, Aaron

2018-01-01

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

The Kinematics of Multiple-peaked Lyα Emission in Star-forming Galaxies at z ~ 2-3

Science.gov (United States)

Kulas, Kristin R.; Shapley, Alice E.; Kollmeier, Juna A.; Zheng, Zheng; Steidel, Charles C.; Hainline, Kevin N.

2012-01-01

We present new results on the Lyα emission-line kinematics of 18 z ~ 2-3 star-forming galaxies with multiple-peaked Lyα profiles. With our large spectroscopic database of UV-selected star-forming galaxies at these redshifts, we have determined that ~30% of such objects with detectable Lyα emission display multiple-peaked emission profiles. These profiles provide additional constraints on the escape of Lyα photons due to the rich velocity structure in the emergent line. Despite recent advances in modeling the escape of Lyα from star-forming galaxies at high redshifts, comparisons between models and data are often missing crucial observational information. Using Keck II NIRSPEC spectra of Hα (z ~ 2) and [O III]λ5007 (z ~ 3), we have measured accurate systemic redshifts, rest-frame optical nebular velocity dispersions, and emission-line fluxes for the objects in the sample. In addition, rest-frame UV luminosities and colors provide estimates of star formation rates and the degree of dust extinction. In concert with the profile sub-structure, these measurements provide critical constraints on the geometry and kinematics of interstellar gas in high-redshift galaxies. Accurate systemic redshifts allow us to translate the multiple-peaked Lyα profiles into velocity space, revealing that the majority (11/18) display double-peaked emission straddling the velocity-field zero point with stronger red-side emission. Interstellar absorption-line kinematics suggest the presence of large-scale outflows for the majority of objects in our sample, with an average measured interstellar absorption velocity offset of langΔv absrang = -230 km s-1. A comparison of the interstellar absorption kinematics for objects with multiple- and single-peaked Lyα profiles indicate that the multiple-peaked objects are characterized by significantly narrower absorption line widths. We compare our data with the predictions of simple models for outflowing and infalling gas distributions around

Development of a low-level, in-line alpha counter (LLILAC)

International Nuclear Information System (INIS)

Gritzo, R.E.; Farnham, J.E.; Fowler, M.M.; Wouters, J.

1996-01-01

This is the final report of a two-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). With the increasing awareness of water contamination issues and the rising consequences of any form of contamination, real-time continuous monitoring is rapidly becoming a necessity. In particular, monitoring for the presence of any radioactive material is paramount. The most difficult of such monitoring tasks is that of detecting alpha-emitting radionuclides in water. Our development of the Low Level In-Line Alpha Counter (LLILAC) addresses the need for on-line, near real-time monitoring of alpha-emitting radionuclides in aqueous streams in a wide variety of applications. Although primarily designed as an on-line instrument for real-time applications, the detector can also be used for long-term in situ/post-closure monitoring. This detection system operates by allowing the stream to be monitored to come in contact with a large number of small rods or tubes made of scintillation material. By maximizing the surface to volume ratio of the scintillator, the response to alpha particles is favored over other types of radiation. Several configurations of scintillator and light collection schemes have been investigated to optimize the detection efficiency. We have also written several Monte Carlo codes to help to predict and understand the detector performance

Spectrophotometry of Bowen resonance fluorescence lines in three planetary nebulae

Science.gov (United States)

O'Dell, C. R.; Miller, Christopher O.

1992-01-01

The results are presented of a uniquely complete, carefully reduced set of observations of the O III Bowen fluorescence lines in the planetary nebulae NGC 6210, NGC 7027, and NGC 7662. A detailed comparison with the predictions of radiative excitation verify that some secondary lines are enhanced by selective population by the charge exchange mechanism involving O IV. Charge exchange is most important in NGC 6210, which is of significantly lower ionization than the other nebulae. In addition to the principal Bowen lines arising from Ly-alpha pumping of the O III O1 line, lines arising from pumping of the O3 line are also observed. Comparison of lines produced by O1 and O3 with the theoretical predictions of Neufeld indicate poor agreement; comparison with the theoretical predictions of Harrington show agreement with NGC 7027 and NGC 7662.

An Intercomparison Study of Two Proximate Damped Lyα Systems with Residual Flux upon the Lyα Absorption Trough toward Quasars

Science.gov (United States)

Xie, Xiaoyi; Zhou, Hongyan; Pan, Xiang; Jiang, Peng; Shi, Xiheng; Ji, Tuo; Zhang, Shaohua; Wu, Shengmiao; Zhong, Zhihao

2018-05-01

In this paper, we present an intercomparison study of two quasars, SDSS J145618.32+340037.2 and SDSS J215331.50–025514.1, which have proximate damped Lyα systems (PDLAs) with residual flux upon the Lyα absorption trough. Though they both have residual flux as luminous as 1043 erg s‑1, their PDLAs are quite different in, e.g., neutral hydrogen column density, metal line absorption strength, high-ionization absorption lines as well as residual flux strength. For J1456+3400, the H I column density is log(N H I /cm–2) = 20.6 ± 0.2, with z abs = 2.3138, nearly identical to the quasar redshift (z = 2.3142) determined from the [O III] emission line. The metallicity of this system is typical of DLAs and there is high ionization therein, suggesting that the PDLA system is multiphase, putting it in the quasar environment. For J2153–0255, we measure the H I column density to be log(N H I /cm–2) = 21.5 ± 0.1 at z abs = 3.511, slightly redshifted with respect to the quasar (z = 3.490) measured from C III]. The metallicity of this system is quite low and there is a lack of significant high-ionization absorption lines therein, suggesting that the system is beyond the quasar host galaxy. The residual flux is wide (∼1000 km s‑1) in J1456, with a significance of ∼8σ, while also wide (∼1500 km s‑1) but with a smaller significance of ∼3σ in J2153. Among many explanations, we find that Lyα fuzz or resonant scattering can be used to explain the residual flux in the two sources while partial coverage cannot be excluded for J1456. By comparing these two cases, together with a similar case reported previously, we suggest that the strength of the residual flux is related to properties such as metallicity and high-ionization absorption lines of PDLAs. The residual flux recorded upon the PDLA absorption trough opens a window for us to see the physical conditions and processes of the quasar environment, and their profile and strength further remind us of their

Resonant line transfer in a fog: using Lyman-alpha to probe tiny structures in atomic gas

Science.gov (United States)

Gronke, Max; Dijkstra, Mark; McCourt, Michael; Peng Oh, S.

2017-11-01

Motivated by observational and theoretical work that suggest very small-scale (≲ 1 pc) structure in the circumgalactic medium of galaxies and in other environments, we study Lyman-α (Lyα) radiative transfer in an extremely clumpy medium with many clouds of neutral gas along the line of sight. While previous studies have typically considered radiative transfer through sightlines intercepting ≲ 10 clumps, we explored the limit of a very large number of clumps per sightline (up to fc 1000). Our main finding is that, for covering factors greater than some critical threshold, a multiphase medium behaves similarly to a homogeneous medium in terms of the emergent Lyα spectrum. The value of this threshold depends on both the clump column density and the movement of the clumps. We estimated this threshold analytically and compare our findings to radiative transfer simulations with a range of covering factors, clump column densities, radii, and motions. Our results suggest that (I) the success in fitting observed Lyα spectra using homogeneous "shell models" (and the corresponding failure of multiphase models) hints at the presence of very small-scale structure in neutral gas, which is in agreement within a number of other observations; and (II) the recurrent problems of reproducing realistic line profiles from hydrodynamical simulations may be due to their inability to resolve small-scale structure, which causes simulations to underestimate the effective covering factor of neutral gas clouds. The movie associated to Fig. B.2 is available at http://www.aanda.org

Lyα EMITTING GALAXIES AS EARLY STAGES IN GALAXY FORMATION

International Nuclear Information System (INIS)

Cowie, Lennox L.; Barger, Amy J.; Hu, Esther M.

2011-01-01

We present optical spectroscopy of two samples of Galaxy Evolution Explorer grism selected Lyα emitters (LAEs): one at z = 0.195-0.44 and the other at z = 0.65-1.25. We have also observed a comparison sample of galaxies in the same redshift intervals with the same UV magnitude distributions but with no detected Lyα. We use the optical spectroscopy to eliminate active galactic nuclei and to obtain the optical emission-line properties of the samples. We compare the luminosities of the LAEs in the two redshift intervals and show that there is dramatic evolution in the maximum Lyα luminosity over z = 0-1. Focusing on the z = 0.195-0.44 samples alone, we show that there are tightly defined relations between all of the galaxy parameters and the rest-frame equivalent width (EW) of Hα. The higher EW(Hα) sources all have lower metallicities, bluer colors, smaller sizes, and less extinction, consistent with their being in the early stages of the galaxy formation process. We find that 75% ± 12% of the LAEs have EW(Hα) >100 A and, conversely, that 31% ± 13% of galaxies with EW(Hα) >100 A are LAEs. We correct the broadband magnitudes for the emission-line contributions and use spectral synthesis fits to estimate the ages of the galaxies. We find a median age of 1.1 x 10 8 yr for the LAE sample and 1.4 x 10 9 yr for the UV-continuum sample without detected Lyα. The median metallicity of the LAE sample is 12 + log (O/H) = 8.24, or about 0.4 dex lower than the UV-continuum sample.

In vitro cytotoxicity of alpha conjugates for human pancreatic cancer cell lines

International Nuclear Information System (INIS)

Qu, C.; Li, Y.; Rizvi, M.A.; Allen, B.; Samra, J.; Smith, R.

2003-01-01

Targeted Alpha therapy (TAT) can inhibit the growth of micrometastases by selectively killing isolated and preangiogenic clusters of cancer cells. The aim of this study is to demonstrate the cytotoxicity of different alpha conjugates in vitro to human metastatic pancreatic cancer cell lines (CAPAN-1, CFPAN-1 and PANC-1). We are labeling the C595 and J591 (non-specific controls) monoclonal antibodies (Mabs) with 213 Bi were performed according to the standard methods in our laboratory. 213 Bi-C595 is specifically cytotoxic to CAPAN-1, CFPAN-1 and PANC-1cell lines in a concentration-dependent fashion. While non-specific alpha conjugates only killed very small fractions of pancreatic cancer cells. These alpha conjugates might be useful agents for the treatment of micro-metastases in pancreatic cancer patients with over-expression of the targeted receptors

ON THE REDSHIFT EVOLUTION OF THE Lyα ESCAPE FRACTION AND THE DUST CONTENT OF GALAXIES

International Nuclear Information System (INIS)

Hayes, Matthew; Schaerer, Daniel; Oestlin, Goeran; Mas-Hesse, J. Miguel; Atek, Hakim; Kunth, Daniel

2011-01-01

The Lyα emission line has been proven to be a powerful tool for studying evolving galaxies at the highest redshift. However, in order to use Lyα as a physical probe of galaxies, it becomes vital to know the Lyα escape fraction (f Lyα esc ). Unfortunately, due to the resonant nature of Lyα, f Lyα esc may vary unpredictably and requires empirical measurement. Here, we compile Lyα luminosity functions (LFs) between redshifts z = 0 and 8 and, combined with Hα and ultraviolet data, assess how f Lyα esc evolves with redshift. We find a strong upward evolution in f Lyα esc over the range z = 0.3-6, which is well fit by the power law f Lyα esc ∝(1 + z) ξ with ξ = (2.57 +0.19 -0.12 ). This predicts that f Lyα esc should reach unity at z = 11.1. By comparing f Lyα esc and E B-V in individual galaxies we derive an empirical relationship between f Lyα esc and E B-V , which includes resonance scattering and can explain the redshift evolution of f Lyα esc between z = 0 and 6 purely as a function of the evolution in the dust content of galaxies. Beyond z ∼ 6.5, f Lyα esc drops more substantially, an effect attributed to either ionizing photon leakage, or an increase in the neutral gas fraction of the intergalactic medium. While distinguishing between these two scenarios may be extremely challenging, by framing the problem this way we remove the uncertainty of the halo mass from Lyα-based tests of reionization. We finally derive a new method by which to estimate the dust content of galaxies, based purely upon the observed Lyα and UV LFs. These data are characterized by an exponential with an e-folding scale of z EBV ∼ 3.4.

Activating the Wnt/β-Catenin Pathway for the Treatment of Melanoma--Application of LY2090314, a Novel Selective Inhibitor of Glycogen Synthase Kinase-3.

Directory of Open Access Journals (Sweden)

Jennifer M Atkinson

Full Text Available It has previously been observed that a loss of β-catenin expression occurs with melanoma progression and that nuclear β-catenin levels are inversely proportional to cellular proliferation, suggesting that activation of the Wnt/β-catenin pathway may provide benefit for melanoma patients. In order to further probe this concept we tested LY2090314, a potent and selective small-molecule inhibitor with activity against GSK3α and GSK3β isoforms. In a panel of melanoma cell lines, nM concentrations of LY2090314 stimulated TCF/LEF TOPFlash reporter activity, stabilized β-catenin and elevated the expression of Axin2, a Wnt responsive gene and marker of pathway activation. Cytotoxicity assays revealed that melanoma cell lines are very sensitive to LY2090314 in vitro (IC50 ~10 nM after 72hr of treatment in contrast to other solid tumor cell lines (IC50 >10 uM as evidenced by caspase activation and PARP cleavage. Cell lines harboring mutant B-RAF or N-RAS were equally sensitive to LY2090314 as were those with acquired resistance to the BRAF inhibitor Vemurafenib. shRNA studies demonstrated that β-catenin stabilization is required for apoptosis following treatment with the GSK3 inhibitor since the sensitivity of melanoma cell lines to LY290314 could be overcome by β-catenin knockdown. We further demonstrate that in vivo, LY2090314 elevates Axin2 gene expression after a single dose and produces tumor growth delay in A375 melanoma xenografts with repeat dosing. The activity of LY2090314 in preclinical models suggests that the role of Wnt activators for the treatment of melanoma should be further explored.

Determining coronal electron temperatures from observations with UVCS/SOHO

Science.gov (United States)

Fineschi, S.; Esser, R.; Habbal, S. R.; Karovska, M.; Romoli, M.; Strachan, L.; Kohl, J. L.; Huber, M. C. E.

1995-01-01

The electron temperature is a fundamental physical parameter of the coronal plasma. Currently, there are no direct measurements of this quantity in the extended corona. Observations with the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the upcoming Solar and Heliospheric Observatory (SOHO) mission can provide the most direct determination of the electron kinetic temperature (or, more precisely, the electron velocity distribution along the line of sight). This measurement is based on the observation of the Thomson-scattered Lyman alpha (Ly-alpha) profile. This observation is made particularly challenging by the fact that the integrated intensity of the electron-scattered Ly-alpha line is about 10(exp 3) times fainter than that of the resonantly-scattered Ly-alpha component. In addition, the former is distributed across 50 A (FWHM), unlike the latter that is concentrated in 1 A. These facts impose stringent requirements on the stray-light rejection properties of the coronagraph/spectrometer, and in particular on the requirements for the grating. We make use of laboratory measurements of the UVCS Ly-alpha grating stray-light, and of simulated electron-scattered Ly-alpha profiles to estimate the expected confidence levels of electron temperature determination. Models of different structures typical of the corona (e.g., streamers, coronal holes) are used for this parameter study.

A Faint Flux-limited Lyα Emitter Sample at z ˜ 0.3

Science.gov (United States)

Wold, Isak G. B.; Finkelstein, Steven L.; Barger, Amy J.; Cowie, Lennox L.; Rosenwasser, Benjamin

2017-10-01

We present a flux-limited sample of z ˜ 0.3 Lyα emitters (LAEs) from Galaxy Evolution Explorer (GALEX) grism spectroscopic data. The published GALEX z ˜ 0.3 LAE sample is pre-selected from continuum-bright objects and thus is biased against high equivalent width (EW) LAEs. We remove this continuum pre-selection and compute the EW distribution and the luminosity function of the Lyα emission line directly from our sample. We examine the evolution of these quantities from z ˜ 0.3 to 2.2 and find that the EW distribution shows little evidence for evolution over this redshift range. As shown by previous studies, the Lyα luminosity density from star-forming (SF) galaxies declines rapidly with declining redshift. However, we find that the decline in Lyα luminosity density from z = 2.2 to z = 0.3 may simply mirror the decline seen in the Hα luminosity density from z = 2.2 to z = 0.4, implying little change in the volumetric Lyα escape fraction. Finally, we show that the observed Lyα luminosity density from AGNs is comparable to the observed Lyα luminosity density from SF galaxies at z = 0.3. We suggest that this significant contribution from AGNs to the total observed Lyα luminosity density persists out to z ˜ 2.2. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.

Effect of intrathecal non-NMDA EAA receptor antagonist LY293558 in rats: a new class of drugs for spinal anesthesia.

Science.gov (United States)

Von Bergen, Nicholas H; Subieta, Alberto; Brennan, Timothy J

2002-07-01

Excitatory amino acid receptors are important for both sensory and motor function in the spinal cord. We studied the effects of intrathecal LY293558, a competitive non-N-methyl-D-aspartate excitatory amino acid receptor antagonist, on motor and sensory function in rats to determine whether drugs blocking these receptors could potentially be used as alternative agents to local anesthetics for spinal anesthesia. Rats were tested before and 15-240 min after intrathecal injection of 5 nmol (in 10 microl) LY293558. Sensory function was tested at the hind paw using withdrawal response to pin prick and withdrawal to pinch with sharp forceps. Motor performance (ambulation, placing reflex, and Rotorod time), blood pressure, and heart rate were also evaluated. Some tests were repeated the next day. Responses after LY293558 were compared to injection of 40 microl bupivacaine, 0.75%. Pin-prick responses at the forepaw, chest, abdomen, hind leg, and hind paw were also examined after intrathecal LY293558. Intrathecal LY293558 blocked both sensory and motor responses through 180 min; complete recovery was present the following day. No change in blood pressure or heart rate occurred. The effects of LY293558 were more pronounced and sustained than those of bupivacaine. Segmental blockade of the response to pin prick was present after LY293558. Drugs like LY293558 that block alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA)/kainate receptors may be an alternative to local anesthetics for spinal anesthesia in humans.

Polymeric Nano-Micelles as Novel Cargo-Carriers for LY2157299 Liver Cancer Cells Delivery

Directory of Open Access Journals (Sweden)

Nemany Abdelhamid Nemany Hanafy

2018-03-01

Full Text Available LY2157299 (LY, which is very small molecule bringing high cancer diffusion, is a pathway antagonist against TGFβ. LY dosage can be diluted by blood plasma, can be captured by immune system or it might be dissolved during digestion in gastrointestinal tract. The aim of our study is to optimize a “nano-elastic” carrier to avoid acidic pH of gastrointestinal tract, colon alkaline pH, and anti-immune recognition. Polygalacturonic acid (PgA is not degradable in the gastrointestinal tract due to its insolubility at acidic pH. To avoid PgA solubility in the colon, we have designed its conjugation with Polyacrylic acid (PAA. PgA-PAA conjugation has enhanced their potential use for oral and injected dosage. Following these pre-requisites, novel polymeric nano-micelles derived from PgA-PAA conjugation and loading LY2157299 are developed and characterized. Efficacy, uptake and targeting against a hepatocellular carcinoma cell line (HLF have also been demonstrated.

SILVERRUSH. V. Census of Lyα, [O III] λ5007, Hα, and [C II] 158 μm Line Emission with ∼1000 LAEs at z = 4.9–7.0 Revealed with Subaru/HSC

Science.gov (United States)

Harikane, Yuichi; Ouchi, Masami; Shibuya, Takatoshi; Kojima, Takashi; Zhang, Haibin; Itoh, Ryohei; Ono, Yoshiaki; Higuchi, Ryo; Inoue, Akio K.; Chevallard, Jacopo; Capak, Peter L.; Nagao, Tohru; Onodera, Masato; Faisst, Andreas L.; Martin, Crystal L.; Rauch, Michael; Bruzual, Gustavo A.; Charlot, Stephane; Davidzon, Iary; Fujimoto, Seiji; Hilmi, Miftahul; Ilbert, Olivier; Lee, Chien-Hsiu; Matsuoka, Yoshiki; Silverman, John D.; Toft, Sune

2018-06-01

We investigate Lyα, [O III] λ5007, Hα, and [C II] 158 μm emission from 1124 galaxies at z = 4.9–7.0. Our sample is composed of 1092 Lyα emitters (LAEs) at z = 4.9, 5.7, 6.6, and 7.0 identified by Subaru/Hyper-Suprime-Cam (HSC) narrowband surveys covered by Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH) and 34 galaxies at z = 5.148–7.508 with deep ALMA [C II] 158 μm data in the literature. Fluxes of strong rest-frame optical lines of [O III] and Hα (Hβ) are constrained by significant excesses found in the SPLASH 3.6 and 4.5 μm photometry. At z = 4.9, we find that the rest-frame Hα equivalent width and the Lyα escape fraction f Lyα positively correlate with the rest-frame Lyα equivalent width {EW}}Lyα }0. The {f}Lyα }{--}{EW}}Lyα }0 correlation is similarly found at z ∼ 0–2, suggesting no evolution of the correlation over z ≃ 0–5. The typical ionizing photon production efficiency of LAEs is log(ξ ion/[Hz erg‑1]) ≃ 25.5, significantly (60%–100%) higher than those of LBGs at a given UV magnitude. At z = 5.7–7.0, there exists an interesting turnover trend that the [O III]/Hα flux ratio increases in {EW}}Lyα }0≃ 0{--}30 \\mathringA and then decreases out to {EW}}Lyα }0≃ 130 \\mathringA . We also identify an anticorrelation between a ratio of [C II] luminosity to star formation rate (L [C II]/SFR) and {EW}}Lyα }0 at the >99% confidence level.. We carefully investigate physical origins of the correlations with stellar-synthesis and photoionization models and find that a simple anticorrelation between {EW}}Lyα }0 and metallicity explains self-consistently all of the correlations of Lyα, Hα, [O III]/Hα, and [C II] identified in our study, indicating detections of metal-poor (∼0.03 Z ⊙) galaxies with {EW}}Lyα }0≃ 200 \\mathringA .

Identification of potential target genes of ROR-alpha in THP1 and HUVEC cell lines

Energy Technology Data Exchange (ETDEWEB)

Gulec, Cagri, E-mail: cagri.gulec@gmail.com; Coban, Neslihan, E-mail: neslic@istanbul.edu.tr; Ozsait-Selcuk, Bilge, E-mail: ozsaitb@istanbul.edu.tr; Sirma-Ekmekci, Sema, E-mail: semasirma@gmail.com; Yildirim, Ozlem, E-mail: ozlm-yildirim@hotmail.com; Erginel-Unaltuna, Nihan, E-mail: nihanerginel@yahoo.com

2017-04-01

ROR-alpha is a nuclear receptor, activity of which can be modulated by natural or synthetic ligands. Due to its possible involvement in, and potential therapeutic target for atherosclerosis, we aimed to identify ROR-alpha target genes in monocytic and endothelial cell lines. We performed chromatin immunoprecipitation (ChIP) followed by tiling array (ChIP-on-chip) for ROR-alpha in monocytic cell line THP1 and endothelial cell line HUVEC. Following bioinformatic analysis of the array data, we tested four candidate genes in terms of dependence of their expression level on ligand-mediated ROR-alpha activity, and two of them in terms of promoter occupancy by ROR-alpha. Bioinformatic analyses of ChIP-on-chip data suggested that ROR-alpha binds to genomic regions near the transcription start site (TSS) of more than 3000 genes in THP1 and HUVEC. Potential ROR-alpha target genes in both cell types seem to be involved mainly in membrane receptor activity, signal transduction and ion transport. While SPP1 and IKBKA were shown to be direct target genes of ROR-alpha in THP1 monocytes, inflammation related gene HMOX1 and heat shock protein gene HSPA8 were shown to be potential target genes of ROR-alpha. Our results suggest that ROR-alpha may regulate signaling receptor activity, and transmembrane transport activity through its potential target genes. ROR-alpha seems also to play role in cellular sensitivity to environmental substances like arsenite and chloroprene. Although, the expression analyses have shown that synthetic ROR-alpha ligands can modulate some of potential ROR-alpha target genes, functional significance of ligand-dependent modulation of gene expression needs to be confirmed with further analyses.

The Spectroscopic Properties of Lyα-Emitters at z ˜2.7: Escaping Gas and Photons from Faint Galaxies

Science.gov (United States)

Trainor, Ryan F.; Steidel, Charles C.; Strom, Allison L.; Rudie, Gwen C.

2015-08-01

We present a spectroscopic survey of 318 faint ({R}˜ 27, L˜ 0.1{L}*), Lyα-emission-selected galaxies (LAEs) in regions centered on the positions of hyperluminous QSOs (HLQSOs) at 2.5\\lt z\\lt 3. A sample of 32 LAEs with rest-frame optical emission line spectra from Keck/Multi-Object Spectrometer For InfraRed Exploration (MOSFIRE) are used to interpret the LAE spectra in the context of their systemic redshifts. The fields are part of the Keck Baryonic Structure Survey, which includes substantial ancillary multi-wavelength imaging from both the ground and space. From a quantitative analysis of the diverse Lyα spectral morphologies, including line widths, asymmetries, and multi-peaked profiles, we find that peak widths and separations are typically smaller than among samples of more luminous continuum-selected galaxies (Lyman-break galaxies and their analogs; LBGs) at similar redshifts. We find tentative evidence for an association between Lyα spectral morphology and external illumination by the nearby HLQSO. Using the MOSFIRE subsample, we find that the peak of the resolved (R ≈ 1300) Lyα line is shifted by +200 km s-1 with respect to systemic across a diverse set of galaxies including both LAEs and LBGs. We also find a small number of objects with significantly blueshifted Lyα emission, a potential indicator of accreting gas. The Lyα-to-Hα line ratios measured for the MOSFIRE subset suggest that the LAEs in this sample have Lyα escape fractions {f}{esc,{Ly}α } ≈ 30%, significantly higher than typical LBG samples. Using redshifts calibrated by our MOSFIRE sample, we construct composite LAE spectra, finding the first evidence for metal-enriched outflows in such intrinsically faint high-redshift galaxies. These outflows have smaller continuum covering fractions ({f}{{c}}≈ 0.3) and velocities ({v}{ave} ≈ 100-200 km s-1, {v}{max} ≈ 500 km s-1) than those associated with typical LBGs, suggesting that the gas covering fraction is a likely driver of

The Abundance of Low-Luminosity Lyα Emitters at High Redshift

Science.gov (United States)

Santos, Michael R.; Ellis, Richard S.; Kneib, Jean-Paul; Richard, Johan; Kuijken, Konrad

2004-05-01

We derive the luminosity function of high-redshift Lyα-emitting sources from a deep, blind, spectroscopic survey that utilized strong-lensing magnification by intermediate-redshift clusters of galaxies. We observed carefully selected regions near nine clusters, consistent with magnification factors generally greater than 10 for the redshift range 4.5account our varying intrinsic Lyα line sensitivity as a function of wavelength and sky position. By virtue of the strong magnification factor, we provide constraints on the Lyα luminosity function to unprecedented limits of 1040 ergs s -1, corresponding to a star formation rate of 0.01 Msolar yr-1. Our cumulative z~=5 Lyα luminosity function is consistent with a power-law form n(>L)~L-1 over 1041-1042.5 ergs s-1. When combined with the results of other surveys, limited at higher luminosities, our results suggest evidence for the suppression of star formation in low-mass halos, as predicted in popular models of galaxy formation. Data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Spectrophotometry near the atmospheric cutoff of the strongest Bowen resonance fluorescence lines of O III in two planetary nebulae

Science.gov (United States)

O'Dell, C. R.; Opal, Chet B.

1989-01-01

Spectrophotometric results are presented for the stronger, well-resolved Bowen O III resonance fluorescence emission lines in the planetary nebulae 7027 and NGC 7662 down to and including the intrinsically strong line at 3133 A. These data are combined with results from the IUE atlas of spectra and similar results for the longer wavelength lines by Likkel and Aller (1986) to give the first full coverage of the Bowen lines. Good agreement is found with fluorescence theory for the primary cascade lines, except for the Likkel and Aller results. The efficiency of conversion of the exciting He II Ly-alpha into O III lines is determined, and values comparable to other planetary nebulae are found.

Target specificity, in vivo pharmacokinetics, and efficacy of the putative STAT3 inhibitor LY5 in osteosarcoma, Ewing's sarcoma, and rhabdomyosarcoma.

Directory of Open Access Journals (Sweden)

Peter Y Yu

Full Text Available STAT3 is a transcription factor involved in cytokine and receptor kinase signal transduction that is aberrantly activated in a variety of sarcomas, promoting metastasis and chemotherapy resistance. The purpose of this work was to develop and test a novel putative STAT3 inhibitor, LY5.An in silico fragment-based drug design strategy was used to create LY5, a small molecule inhibitor that blocks the STAT3 SH2 domain phosphotyrosine binding site, inhibiting homodimerization. LY5 was evaluated in vitro demonstrating good biologic activity against rhabdomyosarcoma, osteosarcoma and Ewing's sarcoma cell lines at high nanomolar/low micromolar concentrations, as well as specific inhibition of STAT3 phosphorylation without effects on other STAT3 family members. LY5 exhibited excellent oral bioavailability in both mice and healthy dogs, and drug absorption was enhanced in the fasted state with tolerable dosing in mice at 40 mg/kg BID. However, RNAi-mediated knockdown of STAT3 did not phenocopy the biologic effects of LY5 in sarcoma cell lines. Moreover, concentrations needed to inhibit ex vivo metastasis growth using the PuMA assay were significantly higher than those needed to inhibit STAT3 phosphorylation in vitro. Lastly, LY5 treatment did not inhibit the growth of sarcoma xenografts or prevent pulmonary metastasis in mice.LY5 is a novel small molecule inhibitor that effectively inhibits STAT3 phosphorylation and cell proliferation at nanomolar concentrations. LY5 demonstrates good oral bioavailability in mice and dogs. However LY5 did not decrease tumor growth in xenograft mouse models and STAT3 knockdown did not induce concordant biologic effects. These data suggest that the anti-cancer effects of LY5 identified in vitro were not mediated through STAT3 inhibition.

Target specificity, in vivo pharmacokinetics, and efficacy of the putative STAT3 inhibitor LY5 in osteosarcoma, Ewing's sarcoma, and rhabdomyosarcoma.

Science.gov (United States)

Yu, Peter Y; Gardner, Heather L; Roberts, Ryan; Cam, Hakan; Hariharan, Seethalakshmi; Ren, Ling; LeBlanc, Amy K; Xiao, Hui; Lin, Jiayuh; Guttridge, Denis C; Mo, Xiaokui; Bennett, Chad E; Coss, Christopher C; Ling, Yonghua; Phelps, Mitch A; Houghton, Peter; London, Cheryl A

2017-01-01

STAT3 is a transcription factor involved in cytokine and receptor kinase signal transduction that is aberrantly activated in a variety of sarcomas, promoting metastasis and chemotherapy resistance. The purpose of this work was to develop and test a novel putative STAT3 inhibitor, LY5. An in silico fragment-based drug design strategy was used to create LY5, a small molecule inhibitor that blocks the STAT3 SH2 domain phosphotyrosine binding site, inhibiting homodimerization. LY5 was evaluated in vitro demonstrating good biologic activity against rhabdomyosarcoma, osteosarcoma and Ewing's sarcoma cell lines at high nanomolar/low micromolar concentrations, as well as specific inhibition of STAT3 phosphorylation without effects on other STAT3 family members. LY5 exhibited excellent oral bioavailability in both mice and healthy dogs, and drug absorption was enhanced in the fasted state with tolerable dosing in mice at 40 mg/kg BID. However, RNAi-mediated knockdown of STAT3 did not phenocopy the biologic effects of LY5 in sarcoma cell lines. Moreover, concentrations needed to inhibit ex vivo metastasis growth using the PuMA assay were significantly higher than those needed to inhibit STAT3 phosphorylation in vitro. Lastly, LY5 treatment did not inhibit the growth of sarcoma xenografts or prevent pulmonary metastasis in mice. LY5 is a novel small molecule inhibitor that effectively inhibits STAT3 phosphorylation and cell proliferation at nanomolar concentrations. LY5 demonstrates good oral bioavailability in mice and dogs. However LY5 did not decrease tumor growth in xenograft mouse models and STAT3 knockdown did not induce concordant biologic effects. These data suggest that the anti-cancer effects of LY5 identified in vitro were not mediated through STAT3 inhibition.

How to estimate the 3D power spectrum of the Lyman-α forest

Science.gov (United States)

Font-Ribera, Andreu; McDonald, Patrick; Slosar, Anže

2018-01-01

We derive and numerically implement an algorithm for estimating the 3D power spectrum of the Lyman-α (Lyα) forest flux fluctuations. The algorithm exploits the unique geometry of Lyα forest data to efficiently measure the cross-spectrum between lines of sight as a function of parallel wavenumber, transverse separation and redshift. We start by approximating the global covariance matrix as block-diagonal, where only pixels from the same spectrum are correlated. We then compute the eigenvectors of the derivative of the signal covariance with respect to cross-spectrum parameters, and project the inverse-covariance-weighted spectra onto them. This acts much like a radial Fourier transform over redshift windows. The resulting cross-spectrum inference is then converted into our final product, an approximation of the likelihood for the 3D power spectrum expressed as second order Taylor expansion around a fiducial model. We demonstrate the accuracy and scalability of the algorithm and comment on possible extensions. Our algorithm will allow efficient analysis of the upcoming Dark Energy Spectroscopic Instrument dataset.

THE MUSCLES TREASURY SURVEY. II. INTRINSIC LY α AND EXTREME ULTRAVIOLET SPECTRA OF K AND M DWARFS WITH EXOPLANETS

Energy Technology Data Exchange (ETDEWEB)

Youngblood, Allison; France, Kevin; Loyd, R. O. Parke [Laboratory for Atmospheric and Space Physics, University of Colorado, 600 UCB, Boulder, CO 80309 (United States); Linsky, Jeffrey L. [JILA, University of Colorado and NIST, 440 UCB, Boulder, CO 80309 (United States); Redfield, Seth [Astronomy Department and Van Vleck Observatory, Wesleyan University, Middletown, CT 06459-0123 (United States); Schneider, P. Christian [European Space Research and Technology Centre (ESA/ESTEC), Keplerlaan 1, 2201 AZ Noordwijk (Netherlands); Wood, Brian E. [Naval Research Laboratory, Space Science Division, Washington, DC 20375 (United States); Brown, Alexander [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Froning, Cynthia [Dept. of Astronomy C1400, University of Texas, Austin, TX 78712 (United States); Miguel, Yamila [Laboratoire Lagrange, Universite de Nice-Sophia Antipolis, Observatoire de la Cote d’Azur, CNRS, Blvd de l’Observatoire, CS 34229, F-06304 Nice cedex 4 (France); Rugheimer, Sarah [Department of Earth and Environmental Sciences, Irvine Building, University of St. Andrews, St. Andrews KY16 9AL (United Kingdom); Walkowicz, Lucianne, E-mail: allison.youngblood@colorado.edu [The Adler Planetarium, 1300 S Lakeshore Dr, Chicago, IL 60605 (United States)

2016-06-20

The ultraviolet (UV) spectral energy distributions (SEDs) of low-mass (K- and M-type) stars play a critical role in the heating and chemistry of exoplanet atmospheres, but are not observationally well-constrained. Direct observations of the intrinsic flux of the Ly α line (the dominant source of UV photons from low-mass stars) are challenging, as interstellar H i absorbs the entire line core for even the closest stars. To address the existing gap in empirical constraints on the UV flux of K and M dwarfs, the MUSCLES Hubble Space Telescope Treasury Survey has obtained UV observations of 11 nearby M and K dwarfs hosting exoplanets. This paper presents the Ly α and extreme-UV spectral reconstructions for the MUSCLES targets. Most targets are optically inactive, but all exhibit significant UV activity. We use a Markov Chain Monte Carlo technique to correct the observed Ly α profiles for interstellar absorption, and we employ empirical relations to compute the extreme-UV SED from the intrinsic Ly α flux in ∼100 Å bins from 100–1170 Å. The reconstructed Ly α profiles have 300 km s{sup −1} broad cores, while >1% of the total intrinsic Ly α flux is measured in extended wings between 300 and 1200 km s{sup −1}. The Ly α surface flux positively correlates with the Mg ii surface flux and negatively correlates with the stellar rotation period. Stars with larger Ly α surface flux also tend to have larger surface flux in ions formed at higher temperatures, but these correlations remain statistically insignificant in our sample of 11 stars. We also present H i column density measurements for 10 new sightlines through the local interstellar medium.

Solution In-Line Alpha Counter (SILAC) Instruction Manual-Version 4.00

International Nuclear Information System (INIS)

Alferink, Steven M.; Farnham, Joel E.; Fowler, Malcolm M.; Wong, Amy S.

2002-01-01

The Solution In-Line Alpha Counter (SILAC) provides near real-time alpha activity measurements of aqueous solutions in gloveboxes located in the Plutonium Facility (TA-55) at Los Alamos National Laboratory (LANL). The SILAC detector and its interface software were first developed by Joel Farnham at LANL [1]. This instruction manual describes the features of the SILAC interface software and contains the schematic and fabrication instructions for the detector

LY-293558. Eli Lilly & Co.

Science.gov (United States)

Gilron, I

2001-09-01

Lilly is developing the racemic compound LY-215490, a selective and competitive AMPA antagonist, as a potential treatment for cerebral infarction, cerebrovascular ischemia, epilepsy and as an analgesic [135089], [158980], [254029], [278691]. By January 2000, LY-293558 was undergoing phase II trials for pain [414000].

Crystal Structure of the FGFR4/LY2874455 Complex Reveals Insights into the Pan-FGFR Selectivity of LY2874455.

Science.gov (United States)

Wu, Daichao; Guo, Ming; Philips, Michael A; Qu, Lingzhi; Jiang, Longying; Li, Jun; Chen, Xiaojuan; Chen, Zhuchu; Chen, Lin; Chen, Yongheng

2016-01-01

Aberrant FGFR4 signaling has been documented abundantly in various human cancers. The majority of FGFR inhibitors display significantly reduced potency toward FGFR4 compared to FGFR1-3. However, LY2874455 has similar inhibition potency for FGFR1-4 with IC50 less than 6.4 nM. To date, there is no published crystal structure of LY2874455 in complex with any kinase. To better understand the pan-FGFR selectivity of LY2874455, we have determined the crystal structure of the FGFR4 kinase domain bound to LY2874455 at a resolution of 2.35 Å. LY2874455, a type I inhibitor for FGFR4, binds to the ATP-binding pocket of FGFR4 in a DFG-in active conformation with three hydrogen bonds and a number of van der Waals contacts. After alignment of the kinase domain sequence of 4 FGFRs, and superposition of the ATP binding pocket of 4 FGFRs, our structural analyses reveal that the interactions of LY2874455 to FGFR4 are largely conserved in 4 FGFRs, explaining at least partly, the broad inhibitory activity of LY2874455 toward 4 FGFRs. Consequently, our studies reveal new insights into the pan-FGFR selectivity of LY2874455 and provide a structural basis for developing novel FGFR inhibitors that target FGFR1-4 broadly.

Regulation of expression of two LY-6 family genes by intron retention and transcription induced chimerism

Directory of Open Access Journals (Sweden)

Mallya Meera

2008-09-01

Full Text Available Abstract Background Regulation of the expression of particular genes can rely on mechanisms that are different from classical transcriptional and translational control. The LY6G5B and LY6G6D genes encode LY-6 domain proteins, whose expression seems to be regulated in an original fashion, consisting of an intron retention event which generates, through an early premature stop codon, a non-coding transcript, preventing expression in most cell lines and tissues. Results The MHC LY-6 non-coding transcripts have shown to be stable and very abundant in the cell, and not subject to Nonsense Mediated Decay (NMD. This retention event appears not to be solely dependent on intron features, because in the case of LY6G5B, when the intron is inserted in the artificial context of a luciferase expression plasmid, it is fully spliced but strongly stabilises the resulting luciferase transcript. In addition, by quantitative PCR we found that the retained and spliced forms are differentially expressed in tissues indicating an active regulation of the non-coding transcript. EST database analysis revealed that these genes have an alternative expression pathway with the formation of Transcription Induced Chimeras (TIC. This data was confirmed by RT-PCR, revealing the presence of different transcripts that would encode the chimeric proteins CSNKβ-LY6G5B and G6F-LY6G6D, in which the LY-6 domain would join to a kinase domain and an Ig-like domain, respectively. Conclusion In conclusion, the LY6G5B and LY6G6D intron-retained transcripts are not subjected to NMD and are more abundant than the properly spliced forms. In addition, these genes form chimeric transcripts with their neighbouring same orientation 5' genes. Of interest is the fact that the 5' genes (CSNKβ or G6F undergo differential splicing only in the context of the chimera (CSNKβ-LY6G5B or G6F-LY6G6C and not on their own.

BROAD Lyα EMISSION FROM THREE NEARBY BL LACERTAE OBJECTS

International Nuclear Information System (INIS)

Stocke, John T.; Danforth, Charles W.; Perlman, Eric S.

2011-01-01

We present far-UV HST/COS spectra of four nearby BL Lac objects. BL Lac spectra are dominated by a smooth, power-law continuum which arises in a relativistic jet. However, the spectra are not necessarily featureless; weak, broad- and/or narrow-line emission is sometimes seen in high-quality optical spectra. We present detections of Lyα emission in HST/COS spectra of Mrk 421 (z = 0.030) and PKS 2005-489 (z = 0.071) as well as an archival HST/GHRS observation of Mrk 501 (z = 0.0337). Archival HST/STIS observations of PKS 2155-304 (z = 0.116) show no Lyα emission to a very low upper limit. Using the assumption that the broad-line region (BLR) clouds are symmetrically placed around the active galactic nucleus (AGN), we use these measured Lyα emission features to constrain either the relativistic Γ values for the ionizing continuum produced by the jet (in the ionization-bounded case) or the mass of warm gas (in the density-bounded case). While realistic Γ values can be obtained for all four cases, the values for Mrk 421 and PKS 2155-304 are high enough to suggest that covering factors of BLR clouds of ∼1%-2% might be required to provide consistency with earlier values of Doppler boosting and viewing angles suggested for this class of BL Lacs. This discrepancy also exists in the case of M 87, where the amount of Doppler boosting in our direction is expected to be minimal, again suggestive of a small covering factor of BLR clouds. If, as these small covering factors might suggest, the assumptions of a density-bounded model could be more correct, then the observed Lyα luminosities require that BL Lac/FR 1 nuclei possess very little warm gas (10 -4 to 10 -5 M sun ) as suggested by Guilbert et al. If these clouds are in pressure balance with a hotter (∼10 6 K) gas, the BLR contains too little mass to power the AGN by accretion alone.

The nature of luminous Ly α emitters at z ˜ 2-3: maximal dust-poor starbursts and highly ionizing AGN

Science.gov (United States)

Sobral, David; Matthee, Jorryt; Darvish, Behnam; Smail, Ian; Best, Philip N.; Alegre, Lara; Röttgering, Huub; Mobasher, Bahram; Paulino-Afonso, Ana; Stroe, Andra; Oteo, Iván

2018-06-01

Deep narrow-band surveys have revealed a large population of faint Ly α emitters (LAEs) in the distant Universe, but relatively little is known about the most luminous sources ({L}_{Lyα } ≳ 10^{42.7} erg s-1; L_{Lyα }≳ L^*_{Lyα }). Here we present the spectroscopic follow-up of 21 luminous LAEs at z ˜ 2-3 found with panoramic narrow-band surveys over five independent extragalactic fields (≈4 × 106 Mpc3 surveyed at z ˜ 2.2 and z ˜ 3.1). We use WHT/ISIS, Keck/DEIMOS, and VLT/X-SHOOTER to study these sources using high ionization UV lines. Luminous LAEs at z ˜ 2-3 have blue UV slopes (β =-2.0^{+0.3}_{-0.1}) and high Ly α escape fractions (50^{+20}_{-15} per cent) and span five orders of magnitude in UV luminosity (MUV ≈ -19 to -24). Many (70 per cent) show at least one high ionization rest-frame UV line such as C IV, N V, C III], He II or O III], typically blue-shifted by ≈100-200 km s-1 relative to Ly α. Their Ly α profiles reveal a wide variety of shapes, including significant blue-shifted components and widths from 200 to 4000 km s-1. Overall, 60 ± 11 per cent appear to be active galactic nucleus (AGN) dominated, and at LLyα > 1043.3 erg s-1 and/or MUV sharp transition in the nature of LAEs, from star formation dominated to AGN dominated.

Eclipsing damped Lyα systems in the Sloan Digital Sky Survey Data Release 12★

Science.gov (United States)

Fathivavsari, H.; Petitjean, P.; Jamialahmadi, N.; Khosroshahi, H. G.; Rahmani, H.; Finley, H.; Noterdaeme, P.; Pâris, I.; Srianand, R.

2018-04-01

We present the results of our automatic search for proximate damped Lyα absorption (PDLA) systems in the quasar spectra from the Sloan Digital Sky Survey Data Release 12. We constrain our search to those PDLAs lying within 1500 km s-1 from the quasar to make sure that the broad DLA absorption trough masks most of the strong Lyα emission from the broad line region (BLR) of the quasar. When the Lyα emission from the BLR is blocked by these so-called eclipsing DLAs, narrow Lyα emission from the host galaxy could be revealed as a narrow emission line (NEL) in the DLA trough. We define a statistical sample of 399 eclipsing DLAs with log N(H I) ≥ 21.10. We divide our statistical sample into three subsamples based on the strength of the NEL detected in the DLA trough. By studying the stacked spectra of these subsamples, we found that absorption from high ionization species are stronger in DLAs with stronger NEL in their absorption core. Moreover, absorption from the excited states of species like Si II are also stronger in DLAs with stronger NEL. We also found no correlation between the luminosity of the Lyα NEL and the quasar luminosity. These observations are consistent with a scenario in which the DLAs with stronger NEL are denser and physically closer to the quasar. We propose that these eclipsing DLAs could be the product of the interaction between infalling and outflowing gas. High resolution spectroscopic observation would be needed to shed some light on the nature of these eclipsing DLAs.

Optical Alignment of the Chromospheric Lyman-Alpha SpectroPolarimeter using Sophisticated Methods to Minimize Activities under Vacuum

Science.gov (United States)

Giono, G.; Katsukawa, Y.; Ishikawa, R.; Narukage, N.; Kano, R.; Kubo, M.; Ishikawa, S.; Bando, T.; Hara, H.; Suematsu, Y.;

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-03-01

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

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

International Nuclear Information System (INIS)

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

2017-01-01

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

The odd man out? Might climate explain the lower tree alpha-diversity of African rain forests relative to Amazonian rain forests?

NARCIS (Netherlands)

Parmentier, I.; Malhi, Y.; Senterre, B.; Whittaker, R.J.; Alonso, A.; Balinga, M.P.B.; Bakayoko, A.; Bongers, F.J.J.M.; Chatelain, C.; Comiskey, J.; Cortay, R.; Djuikouo Kamdem, M.N.; Doucet, J.L.; Gauier, L.; Hawthorne, W.D.; Issembe, Y.A.; Kouamé, F.N.; Kouka, L.; Leal, M.E.; Lejoly, J.; Lewis, S.L.; Newbery, D.; Nusbaumer, L.; Parren, M.P.E.; Peh, K.S.H.; Phillips, O.L.; Sheil, D.; Sonké, B.; Sosef, M.S.M.; Sunderland, T.; Stropp, J.; Steege, ter H.; Swaine, M.; Tchouto, P.; Gemerden, van B.S.; Valkenburg, van J.; Wöll, H.

2007-01-01

1. Comparative analyses of diversity variation among and between regions allow testing of alternative explanatory models and ideas. Here, we explore the relationships between the tree alpha-diversity of small rain forest plots in Africa and in Amazonia and climatic variables, to test the explanatory

The physical properties of Lyα emitting galaxies: not just primeval galaxies?

Science.gov (United States)

Pentericci, L.; Grazian, A.; Fontana, A.; Castellano, M.; Giallongo, E.; Salimbeni, S.; Santini, P.

2009-02-01

Aims: We have analyzed a sample of Lyman break galaxies from z ~ 3.5 to z ~ 6 selected from the GOODS-S field as B, V, and i-dropouts, and with spectroscopic observations showing that they have the Lyα line in emission. Our main aim is to investigate their physical properties and their dependence on the emission line characteristic and to shed light on the relation between galaxies with Lyα emission and the general LBG population. Methods: The objects were selected from their optical continuum colors and then spectroscopically confirmed by the GOODS collaboration and other campaigns. From the public spectra we derived the main properties of the Lyα emission such as total flux and rest frame EW. We then used complete photometry, from U band to mid-infrared from the GOODS-MUSIC database, and through standard spectro-photometric techniques we derived the physical properties of the galaxies, such as total stellar mass, stellar ages, star formation rates, and dust content. Finally we investigated the relation between emission line and physical properties. Results: Although most galaxies are fit by young stellar populations, a small but non negligible fraction has SEDs that cannot be represented well by young models and require considerably older stellar component, up to ~1 Gyr. There is no apparent relation between age and EW: some of the oldest galaxies have high line EW, and should be also selected in narrow-band surveys. Therefore not all Lyα emitting galaxies are primeval galaxies in the very early stages of formation, as is commonly assumed. We also find a range of stellar populations, with masses from 5 × 108 M_⊙ to 5 × 1010 M_⊙ and SFR from few to 60 M_⊙ yr-1. Although there is no net correlation between mass and EW, we find a significant lack of massive galaxies with high EW, which could be explained if the most massive galaxies were either dustier and/or if they contained more neutral gas than less massive objects. Finally we find that more than

Characterization of the binding of radioiodinated hybrid recombinant IFN-alpha A/D to murine and human lymphoid cell lines

International Nuclear Information System (INIS)

Faltynek, C.R.; Princler, G.L.; Schwabe, M.; Shata, M.T.; Lewis, G.K.; Kamin-Lewis, R.M.

1990-01-01

The hybrid recombinant human interferon (IFN) rIFN-alpha A/D was radioiodinated. Specific binding of [125I]rIFN-alpha A/D was observed with both human and murine cell lines. The binding of [125I]rIFN-alpha A/D to human Daudi cells had similar characteristics to the previously described binding of [125I]rIFN-alpha A or -alpha 2. The following lines of evidence demonstrated that [125I]rIFN-alpha A/D bound with high affinity to the same receptor on murine cells as murine IFN-alpha and -beta: (i) the binding of [125I]rIFN-alpha A/D to murine LBRM cells was inhibited to a similar extent by natural murine IFN-alpha, natural murine IFN-beta, and rIFN-A/D; (ii) the Kd (approximately 2 X 10(-10) M) obtained from both competition experiments and saturation binding experiments with [125I]rIFN-alpha A/D was comparable to the previously reported Kd for the binding of natural murine IFN-alpha and -beta to other murine cell lines; (iii) the size of the cross-linked [125I]rIFN-alpha A/D receptor complex formed on murine LBRM cells was similar to the previously reported cross-linked complex formed after binding radioiodinated natural murine IFN-beta to other murine cell lines. Due to the current lack of readily available recombinant murine IFN-alpha or -beta for radiolabeling and the previously demonstrated biological activity of rIFN-alpha A/D on murine cells, [125I]rIFN-alpha A/D should prove to be a useful reagent for further studies of murine IFN receptors

Extended and broad Ly α emission around a BAL quasar at z ˜ 5

Science.gov (United States)

Ginolfi, M.; Maiolino, R.; Carniani, S.; Arrigoni Battaia, F.; Cantalupo, S.; Schneider, R.

2018-05-01

In this work we report deep MUSE observations of a broad absorption line (BAL) quasar at z ˜ 5, revealing a Ly α nebula with a maximum projected linear size of ˜60 kpc around the quasar (down to our 2σ SB limit per layer of ˜ 9× 10^{-19} erg s^{-1} cm^{-2} arcsec^{-2} for a 1 arcsec2 aperture). After correcting for the cosmological surface brightness dimming, we find that our nebula, at z ˜ 5, has an intrinsically less extended Ly α emission than nebulae at lower redshift. However, such a discrepancy is greatly reduced when referring to comoving distances, which take into account the cosmological growth of dark matter (DM) haloes, suggesting a positive correlation between the size of Ly α nebulae and the sizes of DM haloes/structures around quasars. Differently from the typical nebulae around radio-quiet non-BAL quasars, in the inner regions (˜10 kpc) of the circumgalactic medium of our source, the velocity dispersion of the Ly α emission is very high (FWHM > 1000 km s-1), suggesting that in our case we may be probing outflowing material associated with the quasar.

Locus specificity in the mutability of mouse lymphoma strain LY-S

International Nuclear Information System (INIS)

Evans, H.H.; Mencl, J.; Horng, M.F.

1985-01-01

Mouse lymphoma L5178Y strains, LY-R and LY-S, are closely related but differ in their sensitivity to the lethal effects of radiation and various chemicals. Strain LY-S was originally isolated in 1961 following a spontaneous change in the sensitivity of cultured LY-R cells to ionizing radiation. The authors previously reported that, although strain LY-S is more sensitive to the lethal effects of ionizing radiation and alkylating agents than strain LY-R, it is markedly less mutable than strain LY-R at the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) locus. The isolated sublines of strains LY-R and LY-S which are heterozygous at the thymidine kinase (TK) locus. The LY-S TK+/- heterozygote, like its TK+/+ parent, is more sensitive to the lethal effects of ionizing radiation and alkylating agents and less mutable at the HGPRT locus by these agents than the LY-R TK+/- heterozygote. However, the LY-S heterozygote is 100 times more mutable by these agents at the TK locus than at the HGRT locus. In contrast to LY-R, the majority of the spontaneous and induced LY-S TK-/- mutants form small colonies in the presence of trifluorothymidine, indicating that in the LY-S heterozygote, the inactivation of the TK gene is accompanied by damage to, or rearrangement of neighboring genes

New Results from the Magellan IMACS Spectroscopic Lyα Survey: NICMOS Observations of Lyα Emitters at z = 5.7

Science.gov (United States)

Henry, Alaina L.; Martin, Crystal L.; Dressler, Alan; McCarthy, Patrick; Sawicki, Marcin

2010-08-01

We present NICMOS J 110 (rest-frame 1200-2100 Å) observations of the three z = 5.7 Lyα emitters discovered in the blind multislit spectroscopic survey by Martin et al. These images confirm the presence of the two sources that were previously only seen in spectroscopic observations. The third source, which is undetected in our J 110 observations, has been detected in narrowband imaging of the Cosmic Origins Survey, so our non-detection implies a rest-frame equivalent width >146 Å (3σ). The two J 110-detected sources have more modest rest-frame equivalent widths of 30-40 Å, but all three are typical of high-redshift Lyα emitters. In addition, the J 110-detected sources have UV luminosities that are within a factor of 2 of L*UV, and sizes that appear compact (r hl~ 0farcs15) in our NIC2 images—consistent with a redshift of 5.7. We use these UV-continuum and Lyα measurements to estimate the i 775-z 850 colors of these galaxies and show that at least one and possibly all three would be missed by the i-dropout Lyman break galaxy selection. These observations help demonstrate the utility of multislit narrowband spectroscopy as a technique for finding faint emission-line galaxies. This work is based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy Inc., under NASA contract NAS 5-26555. These observations are associated with proposal 11183.

EVIDENCE FOR PopIII-LIKE STELLAR POPULATIONS IN THE MOST LUMINOUS Lyα EMITTERS AT THE EPOCH OF REIONIZATION: SPECTROSCOPIC CONFIRMATION

Energy Technology Data Exchange (ETDEWEB)

Sobral, David; Santos, Sérgio [Instituto de Astrofísica e Ciências do Espaço, Universidade de Lisboa, OAL, Tapada da Ajuda, PT1349-018 Lisbon (Portugal); Matthee, Jorryt; Röttgering, Huub J. A. [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Darvish, Behnam; Mobasher, Bahram; Hemmati, Shoubaneh [Department of Physics and Astronomy, University of California, 900 University Avenue, Riverside, CA 92521 (United States); Schaerer, Daniel, E-mail: sobral@iastro.pt [Observatoire de Genève, Département d’Astronomie, Université de Genève, 51 Ch. des Maillettes, 1290 Versoix (Switzerland)

2015-08-01

Faint Lyα emitters become increasingly rarer toward the reionization epoch (z ∼ 6–7). However, observations from a very large (∼5 deg{sup 2}) Lyα narrow-band survey at z = 6.6 show that this is not the case for the most luminous emitters, capable of ionizing their own local bubbles. Here we present follow-up observations of the two most luminous Lyα candidates in the COSMOS field: “MASOSA” and “CR7.” We used X-SHOOTER, SINFONI, and FORS2 on the Very Large Telescope, and DEIMOS on Keck, to confirm both candidates beyond any doubt. We find redshifts of z = 6.541 and z = 6.604 for “MASOSA” and “CR7,” respectively. MASOSA has a strong detection in Lyα with a line width of 386 ± 30 km s{sup −1} (FWHM) and with very high EW{sub 0} (>200 Å), but undetected in the continuum, implying very low stellar mass and a likely young, metal-poor stellar population. “CR7,” with an observed Lyα luminosity of 10{sup 43.92±0.05} erg s{sup −1} is the most luminous Lyα emitter ever found at z > 6 and is spatially extended (∼16 kpc). “CR7” reveals a narrow Lyα line with 266 ± 15 km s{sup −1} FWHM, being detected in the near-infrared (NIR) (rest-frame UV; β = −2.3 ± 0.1) and in IRAC/Spitzer. We detect a narrow He ii 1640 Å emission line (6σ, FWHM = 130 ± 30 km s{sup −1}) in CR7 which can explain the clear excess seen in the J-band photometry (EW{sub 0} ∼ 80 Å). We find no other emission lines from the UV to the NIR in our X-SHOOTER spectra (He ii/O iii] 1663 Å > 3 and He ii/C iii] 1908 Å > 2.5). We conclude that CR7 is best explained by a combination of a PopIII-like population, which dominates the rest-frame UV and the nebular emission, and a more normal stellar population, which presumably dominates the mass. Hubble Space Telescope/WFC3 observations show that the light is indeed spatially separated between a very blue component, coincident with Lyα and He ii emission, and two red components (∼5 kpc away), which

The dynamic history of the upper forest line ecotone in the northern Andes

NARCIS (Netherlands)

Hooghiemstra, H.; Berrio, J.C.; Groot, M.H.M.; Bogotá-A, R.G.; Moscol Olivera, M.; González-Carranza, Z.; Myster, R.W.

2012-01-01

In the Andean cordilleras very conspicuous ecotones can be found. The transition from continuous upper montane forest to treeless herbaceous vegetation, regionally known as "páramo" (Cleef 1981; Luteyn 1999) is known as the "upper forest line" (UFL) or "timber line" (Holtmeier 2009). Above the UFL

TensorLy: Tensor Learning in Python

NARCIS (Netherlands)

Kossaifi, Jean; Panagakis, Yannis; Pantic, Maja

2016-01-01

Tensor methods are gaining increasing traction in machine learning. However, there are scant to no resources available to perform tensor learning and decomposition in Python. To answer this need we developed TensorLy. TensorLy is a state of the art general purpose library for tensor learning.

Mechanism and computational model for Lyman-{alpha}-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas

Energy Technology Data Exchange (ETDEWEB)

Louchev, Oleg A.; Saito, Norihito; Wada, Satoshi [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Bakule, Pavel [STFC, ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX (United Kingdom); Yokoyama, Koji [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Ishida, Katsuhiko; Iwasaki, Masahiko [Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan)

2011-09-15

We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-{alpha} (Ly-{alpha}) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-{alpha} generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-{alpha} radiation generation can achieve a value of {approx}5x10{sup -4} which is restricted by the total combined absorption of the fundamental and generated radiation.

Ly49Q, a member of the Ly49 family that is selectively expressed on myeloid lineage cells and involved in regulation of cytoskeletal architecture

Science.gov (United States)

Toyama-Sorimachi, Noriko; Tsujimura, Yusuke; Maruya, Mikako; Onoda, Atsuko; Kubota, Toshiyuki; Koyasu, Shigeo; Inaba, Kayo; Karasuyama, Hajime

2004-01-01

Here, we identified and characterized a Ly49 family member, designated as Ly49Q. The Ly49q gene encodes a 273-aa protein with an immunoreceptor tyrosine-based inhibitory motif (ITIM) at the N terminus of its cytoplasmic domain. We show that the ITIM of Ly49Q can recruit SHP-2 and SHP-1 in a tyrosine phosphorylation-dependent manner. In contrast to other known members of the Ly49 family, Ly49Q was found not to be expressed on NK1.1+ cells, but instead was detectable on virtually all Gr-1+ cells, such as myeloid precursors in bone marrow. Monocytes/macrophages also expressed low levels of Ly49Q, and the expression was enhanced by the treatment of cells with IFN-γ. Treatment of activated macrophages with anti-Ly49Q mAb induced rapid formation of polarized actin structures, showing filopodia-like structure on one side and lamellipodial-like structure on the other side. A panel of proteins became tyrosine-phosphorylated in myeloid cells when treated with the mAb. Induction of the phosphorylation depends on the ITIM of Ly49Q. Thus, Ly49Q has unique features different from other known Ly49 family members and appears to be involved in regulation of cytoskeletal architecture of macrophages through ITIM-mediated signaling. PMID:14732700

A Search for Lyα Emission from Galaxies AT 6 < z < 8 Using Deep HST Grism Observations: Discovery of a z = 7.5 Galaxy

Science.gov (United States)

Larson, Rebecca L.; Finkelstein, Steven; Pirzkal, Nor; Ryan, Russell; Tilvi, Vithal; Malhotra, Sangeeta; Rhoads, James; Finkelstein, Keely; Jung, Intae; Christensen, Lise; Cimatti, Andrea; Ferreras, Ignacio; Grogin, Norman; Koekemoer, Anton; Hathi, Nimish; O'Connell, Robert; Östlin, Göran; Pasquali, Anna; Rothberg, Barry; Windhorst, Rogier; FIGS Team

2018-01-01

We have built an automated detection method to find Lyα emission lines in HST grism data from 6 state of the intergalactic medium (IGM) during the epoch of reionization. We use 160 orbits of G102 slitless spectroscopy obtained from HST/WFC3 for the Faint Infrared Grism Survey (FIGS; PI: Malhotra) that were optimized to sample previously-identified high-redshift galaxy candidates. This dataset has already been used to identify one of these candidates, at redshift z = 7.51, which has been observed to have Lyα emission detectable with the HST Grism (Finkelstein et al. 2013; Tilvi et al. 2016). The FIGS data use five separate roll-angles of HST in an effort to mitigate the overall contamination effects of nearby galaxies and we have created a method that accounts for and removes the contamination from surrounding galaxies, while also removing any dispersed continuum light from each individual spectrum (Pirzkal et al. 2017). Using our new automated process we searched for significant (> 3σ) emission lines via two different methods. First, we compared the results for each galaxy across all roll angles and identified significant lines detected in more than one roll angle. Second, we performed a fit to all five roll angles simultaneously, accounting for the total flux of the emission line across all of our spectra. We have examined the spectra for 64 z > 7 candidates in our sample and found one new candidate Lyα emission line at a (> 5σ) level at 1.03µm (FIGS ID: GS2 1406 also named CANDELS ID: z7 PAR2 2909). After comparing this emission line with the broadband photometric colors, we conclude that this line is Lyα at z = 7.542 ± 0.003. This galaxy has the highest Lyα rest-frame equivalent width (EWLyα) yet published at z > 7 (110 ± 14 A).

Observations of nickel, chromium, and zinc in QSO absorption-line systems

International Nuclear Information System (INIS)

Meyer, D.M.; Roth, K.C.

1990-01-01

New observations of Ni II, Cr II, and Zn II in several damped Ly-alpha QSO absorption-line systems at z about 2 are presented. Using the N(Zn II)/N(H I) ratio as a probe of the metallicity and N(Cr II)/N(Zn II) as a measure of the dust content, it is found that the heavy-element abundances in the z = 1.921 system toward the QSO 2206-199N are 20 percent solar and that the dust-to-gas ratio is 11 percent of the Galactic disk value. The observations of these species in the z = 2.309 system toward PHL 957 yield a more extreme metallicity (4 percent solar) and dust-to-gas ratio (3 percent Galactic). In addition, a depletion of Ni in the z = 2.039 absorber toward PKS 0458 - 020 and an absence of C I absorption in the z about 2 damped systems toward 1215 + 333 and 2359 - 022 are found which are consistent with a lack of dust. Among the four damped systems whose Ni, Cr, and Zn abundances have been examined quantitatively to date, all show convincing evidence of much lower metallicities and dust content than the Galactic disk. The implications of these results with regard to the interpretation of the high-redshift damped Ly-alpha systems as an evolving population of young galaxies are discussed. 41 refs

The effect of an homogeneous magnetic field on the line profiles of hydrogen; Effet d'un champ magnetique uniforme sur les profils des raies de l'hydrogene

Energy Technology Data Exchange (ETDEWEB)

Nguyen, H; Herman, L [Universite de Paris Sorbonne, Lab. de Recherche Physique, 75 - Paris (France); Drawin, H W [Association Euratom-CEA, Centre d' Etudes Nucleaires de Fontenay-aux-Roses, 92 (France)

1966-07-01

The profiles of the hydrogen lines have been calculated taking into account the intermolecular electric field, the electronic collisions, and an external homogeneous magnetic field in which the plasma is imbedded. We considered electron densities N within the range 10{sup 15} {<=} N {<=} 10{sup 18} cm{sup -3} and magnetic field strengths < 1,2 10{sup 5} gauss. These values cover practically most of the experimental conditions in which one is interested in the present state of research. In the present paper we only present the numerical results for the lines Ly-{alpha}, Ly-{beta} and H-{alpha}. For very small magnetic fields our calculated line profiles coincide with the pure Stark profiles recently calculated by GRIEM, KOLB and SHEN (1960). With increasing magnetic fields, important deviations appear. The essential parameters for these deviations are, firstly: the direction of observation with regard to the direction of the magnetic field, and secondly: the ratio between the Zeeman splitting in a magnetic field only and the Stark splitting due to the mean intermolecular electric field. Experimental line profiles have been obtained using a linear discharge tube surrounded by an induction coil, the comparison of tie theoretical profiles with the experimental ones shows a satisfying agreement. The results for the lines originating from higher principal quantum numbers are actually exploited and will be communicated soon. (author) [French] Les profils des raies de l'hydrogene ont ete calcules en tenant compte des collisions electroniques, du champ electrique intermoleculaire et d'un champ magnetique uniforme exterieur. Nous avons considere des concentrations electroniques comprises entre 10{sup 15} cm{sup -3} et 10{sup 18} cm{sup -3} et des champs magnetiques inferieurs ou egaux a 1,2 10{sup 5} gauss. Ces valeurs couvrent pratiquement toutes les conditions experimentales qui ont un interet a l'heure actuelle. Dans le present travail, nous ne donnons que des resultats

Expression of the Ly-6 family proteins Lynx1 and Ly6H in the rat brain is compartmentalized, cell-type specific, and developmentally regulated

DEFF Research Database (Denmark)

Thomsen, Morten Skøtt; Cinar, Betül; Jensen, Majbrit Myrup

2014-01-01

regarding the distribution and developmental regulation of these proteins in the brain. We use protein cross-linking and synaptosomal fractions to demonstrate that the Ly-6 proteins Lynx1 and Ly6H are membrane-bound proteins in the brain, which are present on the cell surface and localize to synaptic...... demonstrate that Lynx1 and Ly6H are expressed in cultured neurons, but not cultured micro- or astroglial cultures. In addition, Lynx1, but not Ly6H was detected in the CSF. Finally, we show that the Ly-6 proteins Lynx1, Lynx2, Ly6H, and PSCA, display distinct expression patterns during postnatal development...

Monte Carlo particle-trajectory models for neutral cometary gases. I. Models and equations. II. The spatial morphology of the Lyman-alpha coma

International Nuclear Information System (INIS)

Combi, M.R.; Smyth, W.H.

1988-01-01

The mathematical derivations of various methods employed in the Monte Carlo particle-trajectory model (MCPTM) are presented, and the application of the MCPTM to the calculation of the photochemical heating of the inner coma through the partial thermalization of cometary hydrogen atoms produced by the photodissociation of water is discussed. This model is then used to explain the observed morphology of the spatially extended Ly-alpha comas of comets. The rocket and Skylab images of the Ly-alpha coma of Comet Kohoutek are examined. 90 references

Specific binding of [3H]LY186126, an analogue of indolidan (LY195115), to cardiac membranes enriched in sarcoplasmic reticulum vesicles

International Nuclear Information System (INIS)

Kauffman, R.F.; Utterback, B.G.; Robertson, D.W.

1989-01-01

LY186126 was found to be a potent inhibitor of type IV cyclic AMP phosphodiesterase located in the sarcoplasmic reticulum of canine cardiac muscle. This compound, a close structural analogue of indolidan (LY195115), was prepared in high specific activity, tritiated form to study the positive inotropic receptor(s) for cardiotonic phosphodiesterase inhibitors such as indolidan and milrinone. A high-affinity binding site for [ 3 H]LY186126 was observed (Kd = 4 nM) in purified preparations of canine cardiac sarcoplasmic reticulum vesicles. Binding was proportional to vesicle protein, was inactivated by subjecting membranes to proteolysis or boiling, and was dependent on added Mg2+. Scatchard analysis suggested the presence of a single class of binding sites in the membrane preparation. Indolidan, milrinone, and LY186126 (all at 1 microM) produced essentially complete displacement of bound [ 3 H]LY186126, while nifedipine, propranolol, and prazosin had little or no effect at this concentration. This represents the first reported use of a radioactive analogue to label the inotropic receptor for cardiotonic phosphodiesterase inhibitors. The results suggest that [ 3 H]LY186126 is a useful radioligand for examining the subcellular site(s) responsible for positive inotropic effects of these drugs

Generating mock data sets for large-scale Lyman-α forest correlation measurements

Energy Technology Data Exchange (ETDEWEB)

Font-Ribera, Andreu [Institut de Ciències de l' Espai (CSIC-IEEC), Campus UAB, Fac. Ciències, torre C5 parell 2, Bellaterra, Catalonia (Spain); McDonald, Patrick [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Miralda-Escudé, Jordi, E-mail: font@ieec.uab.es, E-mail: pvmcdonald@lbl.gov, E-mail: miralda@icc.ub.edu [Institució Catalana de Recerca i Estudis Avançats, Barcelona, Catalonia (Spain)

2012-01-01

Massive spectroscopic surveys of high-redshift quasars yield large numbers of correlated Lyα absorption spectra that can be used to measure large-scale structure. Simulations of these surveys are required to accurately interpret the measurements of correlations and correct for systematic errors. An efficient method to generate mock realizations of Lyα forest surveys is presented which generates a field over the lines of sight to the survey sources only, instead of having to generate it over the entire three-dimensional volume of the survey. The method can be calibrated to reproduce the power spectrum and one-point distribution function of the transmitted flux fraction, as well as the redshift evolution of these quantities, and is easily used for modeling any survey systematic effects. We present an example of how these mock surveys are applied to predict the measurement errors in a survey with similar parameters as the BOSS quasar survey in SDSS-III.

Generating mock data sets for large-scale Lyman-α forest correlation measurements

International Nuclear Information System (INIS)

Font-Ribera, Andreu; McDonald, Patrick; Miralda-Escudé, Jordi

2012-01-01

Massive spectroscopic surveys of high-redshift quasars yield large numbers of correlated Lyα absorption spectra that can be used to measure large-scale structure. Simulations of these surveys are required to accurately interpret the measurements of correlations and correct for systematic errors. An efficient method to generate mock realizations of Lyα forest surveys is presented which generates a field over the lines of sight to the survey sources only, instead of having to generate it over the entire three-dimensional volume of the survey. The method can be calibrated to reproduce the power spectrum and one-point distribution function of the transmitted flux fraction, as well as the redshift evolution of these quantities, and is easily used for modeling any survey systematic effects. We present an example of how these mock surveys are applied to predict the measurement errors in a survey with similar parameters as the BOSS quasar survey in SDSS-III

The HETDEX pilot survey. V. The physical origin of Lyα emitters probed by near-infrared spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Song, Mimi; Finkelstein, Steven L.; Gebhardt, Karl; Hill, Gary J.; Drory, Niv; Chonis, Taylor; Jogee, Shardha; Livermore, Rachael [Department of Astronomy, The University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712 (United States); Ashby, Matthew L. N.; Fazio, Giovanni G.; Huang, Jia-Sheng [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Blanc, Guillermo A. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Bridge, Joanna; Ciardullo, Robin; Gronwall, Caryl; Hagen, Alex; Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Fabricius, Maximilian; Gawiser, Eric [Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854 (United States); Salmon, Brett, E-mail: mmsong@astro.as.utexas.edu [Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); and others

2014-08-10

We present the results from a Very Large Telescope/SINFONI and Keck/NIRSPEC near-infrared spectroscopic survey of 16 Lyα emitters (LAEs) at z = 2.1-2.5 in the COSMOS and GOODS-N fields discovered from the Hobby Eberly Telescope Dark Energy Experiment Pilot Survey. We detect rest-frame optical nebular lines (Hα and/or [O III] λ5007) for 10 of the LAEs and measure physical properties, including the star formation rate (SFR), gas-phase metallicity, gas mass fraction, and Lyα velocity offset. We find that LAEs may lie below the mass-metallicity relation for continuum-selected star-forming galaxies at the same redshift. The LAEs all show velocity shifts of Lyα relative to the systemic redshift ranging between +85 and +296 km s{sup –1} with a mean of +180 km s{sup –1}. This value is smaller than measured for continuum-selected star-forming galaxies at similar redshifts. The Lyα velocity offsets show a moderate correlation with the measured SFR (2.5σ), but no significant correlations are seen with the SFR surface density, specific SFR, stellar mass, or dynamical mass (≲1.5σ). Exploring the role of dust, kinematics of the interstellar medium (ISM), and geometry on the escape of Lyα photons, we find no signature of selective quenching of resonantly scattered Lyα photons. However, we also find no evidence that a clumpy ISM is enhancing the Lyα equivalent width. Our results suggest that the low metallicity in LAEs may be responsible for yielding an environment with a low neutral hydrogen column density and less dust, easing the escape of Lyα photons over that in continuum-selected star-forming galaxies.

The HETDEX pilot survey. V. The physical origin of Lyα emitters probed by near-infrared spectroscopy

International Nuclear Information System (INIS)

Song, Mimi; Finkelstein, Steven L.; Gebhardt, Karl; Hill, Gary J.; Drory, Niv; Chonis, Taylor; Jogee, Shardha; Livermore, Rachael; Ashby, Matthew L. N.; Fazio, Giovanni G.; Huang, Jia-Sheng; Blanc, Guillermo A.; Bridge, Joanna; Ciardullo, Robin; Gronwall, Caryl; Hagen, Alex; Schneider, Donald P.; Fabricius, Maximilian; Gawiser, Eric; Salmon, Brett

2014-01-01

We present the results from a Very Large Telescope/SINFONI and Keck/NIRSPEC near-infrared spectroscopic survey of 16 Lyα emitters (LAEs) at z = 2.1-2.5 in the COSMOS and GOODS-N fields discovered from the Hobby Eberly Telescope Dark Energy Experiment Pilot Survey. We detect rest-frame optical nebular lines (Hα and/or [O III] λ5007) for 10 of the LAEs and measure physical properties, including the star formation rate (SFR), gas-phase metallicity, gas mass fraction, and Lyα velocity offset. We find that LAEs may lie below the mass-metallicity relation for continuum-selected star-forming galaxies at the same redshift. The LAEs all show velocity shifts of Lyα relative to the systemic redshift ranging between +85 and +296 km s –1 with a mean of +180 km s –1 . This value is smaller than measured for continuum-selected star-forming galaxies at similar redshifts. The Lyα velocity offsets show a moderate correlation with the measured SFR (2.5σ), but no significant correlations are seen with the SFR surface density, specific SFR, stellar mass, or dynamical mass (≲1.5σ). Exploring the role of dust, kinematics of the interstellar medium (ISM), and geometry on the escape of Lyα photons, we find no signature of selective quenching of resonantly scattered Lyα photons. However, we also find no evidence that a clumpy ISM is enhancing the Lyα equivalent width. Our results suggest that the low metallicity in LAEs may be responsible for yielding an environment with a low neutral hydrogen column density and less dust, easing the escape of Lyα photons over that in continuum-selected star-forming galaxies.

Proliferative and antiproliferative effects of interferon-gamma and tumor necrosis factor-alpha on cell lines derived from cervical and ovarian malignancies

International Nuclear Information System (INIS)

Mutch, D.G.; Massad, L.S.; Kao, M.S.; Collins, J.L.

1990-01-01

Four human cell lines derived from cervical carcinomas (ME-180, SiHa, HT-3, and MS751) and three human cell lines derived from ovarian carcinomas (SK-OV-3, Caov-3, and NIH:OVCAR-3) were analyzed in vitro to determine the effect of recombinant interferon-gamma and recombinant human tumor necrosis factor-alpha on cell growth and survival. The effects of interferon-gamma, tumor necrosis factor-alpha, and both interferon-gamma and tumor necrosis factor-alpha on cell growth were measured after 24 and 72 hours of incubation by the incorporation of chromium 51. The results of this analysis showed that all seven cell lines were resistant to the antiproliferative action of tumor necrosis factor-alpha, that the growth of most cell lines was inhibited by interferon-gamma by 72 hours of incubation, and that after 72 hours of incubation all cell lines demonstrated a synergistic antiproliferative response to the combination of interferon-gamma and tumor necrosis factor-alpha. However, the effects of these cytokines on cell growth were found to differ among cell lines and varied with the concentration and the duration of incubation. The growth of one cell line (Caov-3) was stimulated by both tumor necrosis factor-alpha and interferon-gamma. These results suggest that the clinical effects of these cytokines on the growth of gynecologic cancers may be more complex than previously supposed

The Role of PPAR Receptors and Leukotriene B4 Receptors in Mediating the Effects of LY293111 in Pancreatic Cancer

Directory of Open Access Journals (Sweden)

Thomas E. Adrian

2008-01-01

Full Text Available Pancreatic cancer is a devastating disease in which current therapies are inadequate. Separate lines of research have identified the 5-lipoxygenase/leukotriene B4 receptor pathway and the PPAR pathway as potential targets for prevention or treatment of this disease. LY293111 was originally designed as a potent leukotriene B4 receptor antagonist for treatment of inflammatory conditions. LY293111 was also known to have inhibitory effects on 5-lipoxygenase, which is upstream of the production of leukotrienes. LY293111 was shown to have potent anticancer effects in pancreatic cancer and several other solid malignancies, where it caused cell cycle arrest and marked apoptosis. Subsequently, it came to light that LY293111 exhibited PPAR agonist activity in addition to its effects on the 5-lipoxygenase pathway. This raises the question of which of the two targets is of greatest importance with regard to the anticancer effects of this agent. The evidence to date is not conclusive, but suggests that the effects of LY293111 may be mediated by both LTB4 receptors and PPAR.

Pharmacological characterization of LY233053: A structurally novel tetrazole-substituted competitive N-methyl-D-aspartic acid antagonist with a short duration of action

International Nuclear Information System (INIS)

Schoepp, D.D.; Ornstein, P.L.; Leander, J.D.; Lodge, D.; Salhoff, C.R.; Zeman, S.; Zimmerman, D.M.

1990-01-01

This study reports the activity of a structurally novel excitatory amino acid receptor antagonist, LY233053 [cis-(+-)-4-[(2H-tetrazol-5-yl)methyl]piperidine-2-carboxylic acid], the first tetrazole-containing competitive N-methyl-D-aspartic acid (NMDA) antagonist. LY233053 potently inhibited NMDA receptor binding to rat brain membranes as shown by the in vitro displacement of [3H] CGS19755 (IC50 = 107 +/- 7 nM). No appreciable affinity in [3H]alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) or [3H]kainate binding assays was observed (IC50 values greater than 10,000 nM). In vitro NMDA receptor antagonist activity was further demonstrated by selective inhibition of NMDA-induced depolarization in cortical wedges (IC50 = 4.2 +/- 0.4 microM vs. 40 microM NMDA). LY233053 was effective after in vivo systemic administration in a number of animal models. In neonatal rats, LY233053 selectively blocked NMDA-induced convulsions (ED50 = 14.5 mg/kg i.p.) with a relatively short duration of action (2-4 hr). In pigeons, LY233053 potently antagonized (ED50 = 1.3 mg/kg i.m.) the behavioral suppressant effects of 10 mg/kg of NMDA. However, a dose of 160 mg/kg, i.m., was required to produce phencyclidine-like catalepsy in pigeons. In mice, LY233053 protected against maximal electroshock-induced seizures at lower doses (ED50 = 19.9 mg/kg i.p.) than those that impaired horizontal screen performance (ED50 = 40.9 mg/kg i.p.). Cholinergic and GABAergic neuronal degenerations after striatal infusion of NMDA were prevented by single or multiple i.p. doses of LY233053. In summary, the antagonist activity of LY233053 after systemic administration demonstrates potential therapeutic value in conditions of neuronal cell loss due to NMDA receptor excitotoxicity

Regulation of Akt and Wnt signaling by the group II metabotropic glutamate receptor antagonist LY341495 and agonist LY379268.

Science.gov (United States)

Sutton, Laurie P; Rushlow, Walter J

2011-06-01

Metabotropic glutamate receptors 2/3 (mGlu(2/3)) have been implicated in schizophrenia and as a novel treatment target for schizophrenia. The current study examined whether mGlu(2/3) regulates Akt (protein kinase B) and Wnt (Wingless/Int-1) signaling, two cascades associated with schizophrenia and modified by antipsychotics. Western blotting revealed increases in phosphorylated Akt (pAkt) and phosphorylated glycogen synthase kinase-3 (pGSK-3) following acute and repeated treatment of LY379268 (mGlu(2/3) agonist), whereas increases in dishevelled-2 (Dvl-2), dishevelled-3 (Dvl-3), GSK-3 and β-catenin were only observed following repeated treatment. LY341495 (mGlu(2/3) antagonist) induced the opposite response compared with LY379268. Co-immunoprecipitation experiments showed an association between the mGlu(2/3) complex and Dvl-2 providing a possible mechanism to explain how the mGlu(2/3) can mediate changes in Wnt signaling. However, there was no association between the mGlu(2/3) complex and Akt suggesting that changes in Akt signaling following LY341495 and LY379268 treatments may not be directly mediated by the mGlu(2/3) . Finally, an increase in locomotor activity induced by LY341495 treatment correlated with increased pAkt and pGSK-3 levels and was attenuated by the administration of the GSK-3 inhibitor, SB216763. Overall, the results suggest that mGlu(2/3) regulates Akt and Wnt signaling and LY379268 treatment has overlapping effects with D(2) dopamine receptor antagonists (antipsychotic drugs). © 2011 The Authors. Journal of Neurochemistry © 2011 International Society for Neurochemistry.

New evidence from the Lyman-alpha forest concerning the formation of galaxies

Energy Technology Data Exchange (ETDEWEB)

Wolfe, A M

1986-12-17

A new type of survey for galaxies with z > 2 is described. The idea is to search for the spectroscopic imprint that the H1 disc of a foreground galaxy leaves on radiation emitted by a background QSO; namely, a Lyman-..cap alpha.. absorption line broadened by radiation damping. A continuing survey has revealed the presence of 15 damped L..cap alpha.. lines with redshifts between 1.8 and 2.8 in the spectra of 68 QSOs. In comparison, no more than three discs with the properties of nearby galaxies should have been detected. Furthermore, the mean column density of the 15 absorbers, = 1.4 x 10/sup 21/cm/sup -2/, is much larger than expected for the outskirts of H1 discs. The statistical and physical evidence accumulated suggests that the damped L..cap alpha.. systems are a distinct population of absorbers with properties reminiscent of H1 discs. It is concluded that the progenitors of the baryon content of nearby galaxies have been detected. The implications for theories of galaxy formations of the discovery of this damped population of absorbers are explained.

The mGlu2/3 Receptor Agonists LY354740 and LY379268 Differentially Regulate Restraint-Stress-Induced Expression of c-Fos in Rat Cerebral Cortex

Directory of Open Access Journals (Sweden)

M. M. Menezes

2013-01-01

Full Text Available Metabotropic glutamate 2/3 (mGlu2/3 receptors have emerged as potential therapeutic targets due to the ability of mGlu2/3 receptor agonists to modulate excitatory transmission at specific synapses. LY354740 and LY379268 are selective and potent mGlu2/3 receptor agonists that show both anxiolytic- and antipsychotic-like effects in animal models. We compared the efficacy of LY354740 and LY379268 in attenuating restraint-stress-induced expression of the immediate early gene c-Fos in the rat prelimbic (PrL and infralimbic (IL cortex. LY354740 (10 and 30 mg/kg, i.p. showed statistically significant and dose-related attenuation of stress-induced increase in c-Fos expression, in the rat cortex. By contrast, LY379268 had no effect on restraint-stress-induced c-Fos upregulation (0.3–10 mg/kg, i.p.. Because both compounds inhibit serotonin 2A receptor (5-HT2AR-induced c-Fos expression, we hypothesize that LY354740 and LY379268 have different in vivo properties and that 5-HT2AR activation and restraint stress induce c-Fos through distinct mechanisms.

A novel small molecular STAT3 inhibitor, LY5, inhibits cell viability, cell migration, and angiogenesis in medulloblastoma cells.

Science.gov (United States)

Xiao, Hui; Bid, Hemant Kumar; Jou, David; Wu, Xiaojuan; Yu, Wenying; Li, Chenglong; Houghton, Peter J; Lin, Jiayuh

2015-02-06

Signal transducers and activators of transcription 3 (STAT3) signaling is persistently activated and could contribute to tumorigenesis of medulloblastoma. Numerous studies have demonstrated that inhibition of the persistent STAT3 signaling pathway results in decreased proliferation and increased apoptosis in human cancer cells, indicating that STAT3 is a viable molecular target for cancer therapy. In this study, we investigated a novel non-peptide, cell-permeable small molecule, named LY5, to target STAT3 in medulloblastoma cells. LY5 inhibited persistent STAT3 phosphorylation and induced apoptosis in human medulloblastoma cell lines expressing constitutive STAT3 phosphorylation. The inhibition of STAT3 signaling by LY5 was confirmed by down-regulating the expression of the downstream targets of STAT3, including cyclin D1, bcl-XL, survivin, and micro-RNA-21. LY5 also inhibited the induction of STAT3 phosphorylation by interleukin-6 (IL-6), insulin-like growth factor (IGF)-1, IGF-2, and leukemia inhibitory factor in medulloblastoma cells, but did not inhibit STAT1 and STAT5 phosphorylation stimulated by interferon-γ (IFN-γ) and EGF, respectively. In addition, LY5 blocked the STAT3 nuclear localization induced by IL-6, but did not block STAT1 and STAT5 nuclear translocation mediated by IFN-γ and EGF, respectively. A combination of LY5 with cisplatin or x-ray radiation also showed more potent effects than single treatment alone in the inhibition of cell viability in human medulloblastoma cells. Furthermore, LY5 demonstrated a potent inhibitory activity on cell migration and angiogenesis. Taken together, these findings indicate LY5 inhibits persistent and inducible STAT3 phosphorylation and suggest that LY5 is a promising therapeutic drug candidate for medulloblastoma by inhibiting persistent STAT3 signaling. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

BROADBAND IMAGING SEGREGATION OF z ∼ 3 Lyα EMITTING AND Lyα ABSORBING GALAXIES

International Nuclear Information System (INIS)

Cooke, Jeff

2009-01-01

The spectral properties of Lyman break galaxies (LBGs) offer a means to isolate pure samples displaying either dominant Lyα in absorption or Lyα in emission using broadband information alone. We present criteria developed using a large z ∼ 3 LBG spectroscopic sample from the literature that enables large numbers of each spectral type to be gathered in photometric data, providing good statistics for multiple applications. In addition, we find that the truncated faint, blue-end tail of z ∼ 3 LBG population overlaps and leads directly into an expected Lyα emitter (LAE) population. As a result, we present simple criteria to cleanly select large numbers of z ∼ 3 LAEs in deep broadband surveys. We present the spectroscopic results of 32r' ∼< 25.5 LBGs and r' ∼< 27.0 LAEs at z ∼ 3 preselected in the Canada-France-Hawaii Telescope Legacy Survey that confirm these criteria.

Structure of the T cell receptor in a Ti alpha V beta 2, alpha V beta 8-positive T cell line

DEFF Research Database (Denmark)

Hou, X; Dietrich, J; Kuhlmann, J

1994-01-01

not known; however, it has been suggested that each TcR contains two Ti dimers. To gain insight into the structure of the TcR we constructed a Ti alpha V beta 2, alpha V beta 8-positive T cell line which expressed the endogenous human TiV beta 8 and the transfected mouse TiV beta 2 both in association......The T cell receptor (TcR) is composed of at least six different polypeptide chains consisting of the clonotypic Ti heterodimer (Ti alpha beta or Ti gamma delta) and the noncovalently associated CD3 chains (CD3 gamma delta epsilon zeta). The exact number of subunits constituting the TcR is still...... with the endogenous Ti alpha and CD3 chains at the cell surface. Preclearing experiments with radioiodinated cell lysate prepared with digitonin lysis buffer demonstrated that depleting the lysate of Ti alpha V beta 8 by immunoprecipitation with anti V beta 8 monoclonal antibody (mAb) did not reduce the amount of Ti...

Synthesis of[11C]LY186126, an inhibitor of phosphodiesterase

International Nuclear Information System (INIS)

Prenant, C.; Crouzel, C.; Comar, D.; Robertson, D.W.

1992-01-01

LY186126 [1,3-dihydro-1,3,3-trimethyl-5-(1,4,5,6-tetrahydro-4-methyl-6-oxo-3-pyriddazinyl)-2H-indol-2-one ], an analogue of the cardiotonic agent indolidan, is a potent, selective and competitive inhibitor of an isozymic form of cyclic AMP phosphodiesterase. LY186126 was labelled with carbon-11 to permit pharmacological studies in the dog myocardium by positron emission tomography. Alkylation with [ 11 C]methyl iodide of N-norLY186126 (LY-197055) allowed the production of 1.7 GBq (50mCi) of [ 11 C]LY-186126 in 40 min. The product, was purified by HPLC. (author)

SPECTROSCOPIC CONFIRMATION OF THREE z-DROPOUT GALAXIES AT z = 6.844-7.213: DEMOGRAPHICS OF Lyα EMISSION IN z ∼ 7 GALAXIES

International Nuclear Information System (INIS)

Ono, Yoshiaki; Shimasaku, Kazuhiro; Nakajima, Kimihiko; Ouchi, Masami; Mobasher, Bahram; Nayyeri, Hooshang; Dickinson, Mark; Kartaltepe, Jeyhan S.; Penner, Kyle; Weiner, Benjamin J.; Stern, Daniel; Kashikawa, Nobunari; Spinrad, Hyron

2012-01-01

We present the results of our ultra-deep Keck/DEIMOS spectroscopy of z-dropout galaxies in the Subaru Deep Field and Great Observatories Origins Deep Survey's northern field. For 3 out of 11 objects, we detect an emission line at ∼1 μm with a signal-to-noise ratio of ∼10. The lines show asymmetric profiles with high weighted skewness values, consistent with being Lyα, yielding redshifts of z = 7.213, 6.965, and 6.844. Specifically, we confirm the z = 7.213 object in two independent DEIMOS runs with different spectroscopic configurations. The z = 6.965 object is a known Lyα emitter, IOK-1, for which our improved spectrum at a higher resolution yields a robust skewness measurement. The three z-dropouts have Lyα fluxes of 3 × 10 –17 erg s –1 cm –2 and rest-frame equivalent widths EW Lyα 0 = 33-43 Å. Based on the largest spectroscopic sample of 43 z-dropouts, which is the combination of our and previous data, we find that the fraction of Lyα-emitting galaxies (EW Lyα 0 > 25 Å) is low at z ∼ 7; 17% ± 10% and 24% ± 12% for bright (M UV ≅ –21) and faint (M UV ≅ –19.5) galaxies, respectively. The fractions of Lyα-emitting galaxies drop from z ∼ 6 to 7 and the amplitude of the drop is larger for faint galaxies than for bright galaxies. These two pieces of evidence would indicate that the neutral hydrogen fraction of the intergalactic medium increases from z ∼ 6 to 7 and that the reionization proceeds from high- to low-density environments, as suggested by an inside-out reionization model.

AVERAGE METALLICITY AND STAR FORMATION RATE OF Lyα EMITTERS PROBED BY A TRIPLE NARROWBAND SURVEY

International Nuclear Information System (INIS)

Nakajima, Kimihiko; Shimasaku, Kazuhiro; Ono, Yoshiaki; Okamura, Sadanori; Ouchi, Masami; Lee, Janice C.; Ly, Chun; Foucaud, Sebastien; Dale, Daniel A.; Salim, Samir; Finn, Rose; Almaini, Omar

2012-01-01

We present the average metallicity and star formation rate (SFR) of Lyα emitters (LAEs) measured from our large-area survey with three narrowband (NB) filters covering the Lyα, [O II]λ3727, and Hα+[N II] lines of LAEs at z = 2.2. We select 919 z = 2.2 LAEs from Subaru/Suprime-Cam NB data in conjunction with Magellan/IMACS spectroscopy. Of these LAEs, 561 and 105 are observed with KPNO/NEWFIRM near-infrared NB filters whose central wavelengths are matched to redshifted [O II] and Hα nebular lines, respectively. By stacking the near-infrared images of the LAEs, we successfully obtain average nebular-line fluxes of LAEs, the majority of which are too faint to be identified individually by NB imaging or deep spectroscopy. The stacked object has an Hα luminosity of 1.7 × 10 42 erg s –1 corresponding to an SFR of 14 M ☉ yr –1 . We place, for the first time, a firm lower limit to the average metallicity of LAEs of Z ∼> 0.09 Z ☉ (2σ) based on the [O II]/(Hα+[N II]) index together with photoionization models and empirical relations. This lower limit of metallicity rules out the hypothesis that LAEs, so far observed at z ∼ 2, are extremely metal-poor (Z –2 Z ☉ ) galaxies at the 4σ level. This limit is higher than a simple extrapolation of the observed mass-metallicity relation of z ∼ 2 UV-selected galaxies toward lower masses (5 × 10 8 M ☉ ), but roughly consistent with a recently proposed fundamental mass-metallicity relation when the LAEs' relatively low SFR is taken into account. The Hα and Lyα luminosities of our NB-selected LAEs indicate that the escape fraction of Lyα photons is ∼12%-30%, much higher than the values derived for other galaxy populations at z ∼ 2.

SPECTROPOLARIMETRY CONFIRMS CENTRAL POWERING IN A Lyα NEBULA AT z = 3.09

International Nuclear Information System (INIS)

Beck, Melanie; Scarlata, Claudia; Jones, Terry J.; Hayes, Matthew; Dijkstra, Mark

2016-01-01

We present a follow-up study to the imaging polarimetry performed by Hayes et al. on LAB1 in the SSA22 protocluster region. Arguably the most well-known Lyα “blob,” this radio-quiet emission-line nebula likely hosts a galaxy that either is undergoing significant star formation or hosts an active galactic nucleus, or both. We obtain deep, spatially resolved spectropolarimetry of the Lyα emission and detect integrated linear polarization of 9%–13% ± 2%–3% at a distance of approximately 15 kpc north and south of the peak of the Lyα surface brightness with polarization vectors lying tangential to the galactic central source. In these same regions, we also detect a wavelength dependence in the polarization that is low at the center of the Lyα line profile and rises substantially in the wings of the profile. These polarization signatures are easily explained by a weak outflowing shell model. The spectral dependence of the polarization presented here provides a framework for future observations and interpretations of the southern portion of LAB1 in that any model for this system must be able to reproduce this particular spectral dependence. However, questions still remain for the northernmost spur of LAB1. In this region we detect total linear polarization of between 3% and 20% at the 5% significance level. Simulations predict that polarization should increase with radius for a symmetric geometry. That the northern spur does not suggests either that this region is not symmetric (which is likely) and exhibits variations in columns density or that it is kinematically distinct from the rest of LAB1 and powered by another mechanism altogether

SPECTROPOLARIMETRY CONFIRMS CENTRAL POWERING IN A Lyα NEBULA AT z = 3.09

Energy Technology Data Exchange (ETDEWEB)

Beck, Melanie; Scarlata, Claudia; Jones, Terry J. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, 116 Church Street, Minneapolis, MN 55455 (United States); Hayes, Matthew [Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden); Dijkstra, Mark, E-mail: beck@astro.umn.edu [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, N-0315 Oslo (Norway)

2016-02-20

We present a follow-up study to the imaging polarimetry performed by Hayes et al. on LAB1 in the SSA22 protocluster region. Arguably the most well-known Lyα “blob,” this radio-quiet emission-line nebula likely hosts a galaxy that either is undergoing significant star formation or hosts an active galactic nucleus, or both. We obtain deep, spatially resolved spectropolarimetry of the Lyα emission and detect integrated linear polarization of 9%–13% ± 2%–3% at a distance of approximately 15 kpc north and south of the peak of the Lyα surface brightness with polarization vectors lying tangential to the galactic central source. In these same regions, we also detect a wavelength dependence in the polarization that is low at the center of the Lyα line profile and rises substantially in the wings of the profile. These polarization signatures are easily explained by a weak outflowing shell model. The spectral dependence of the polarization presented here provides a framework for future observations and interpretations of the southern portion of LAB1 in that any model for this system must be able to reproduce this particular spectral dependence. However, questions still remain for the northernmost spur of LAB1. In this region we detect total linear polarization of between 3% and 20% at the 5% significance level. Simulations predict that polarization should increase with radius for a symmetric geometry. That the northern spur does not suggests either that this region is not symmetric (which is likely) and exhibits variations in columns density or that it is kinematically distinct from the rest of LAB1 and powered by another mechanism altogether.

KECK SPECTROSCOPY OF LYMAN-BREAK GALAXIES AND ITS IMPLICATIONS FOR THE UV-CONTINUUM AND Lyα LUMINOSITY FUNCTIONS AT z > 6

International Nuclear Information System (INIS)

Jiang Linhua; Egami, Eiichi; Walth, Gregory; Kashikawa, Nobunari; Matsuda, Yuichi; Shimasaku, Kazuhiro; Nagao, Tohru; Ota, Kazuaki; Ouchi, Masami

2011-01-01

We present Keck spectroscopic observations of z > 6 Lyman-break galaxy (LBG) candidates in the Subaru Deep Field (SDF). The candidates were selected as i'-dropout objects down to z' = 27 AB magnitudes from an ultra-deep SDF z'-band image. With the Keck spectroscopy we identified 19 LBGs with prominent Lyα emission lines at 6 ≤ z ≤ 6.4. The median value of the Lyα rest-frame equivalent widths (EWs) is ∼50 Å, with four EWs >100 Å. This well-defined spectroscopic sample spans a UV-continuum luminosity range of –21.8 ≤ M UV ≤ –19.5 (0.6 ∼ 5 L* UV ) and a Lyα luminosity range of (0.3-3) × 10 43 erg s –1 (0.3-3 L* Lyα ). We derive the UV and Lyα luminosity functions (LFs) from our sample at (z) ∼ 6.2 after we correct for sample incompleteness. We find that our measurement of the UV LF is consistent with the results of previous studies based on photometric LBG samples at 5 6.

The Lyman alpha reference sample. II. Hubble space telescope imaging results, integrated properties, and trends

Energy Technology Data Exchange (ETDEWEB)

Hayes, Matthew; Östlin, Göran; Duval, Florent; Sandberg, Andreas; Guaita, Lucia; Melinder, Jens; Rivera-Thorsen, Thøger [Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden); Adamo, Angela [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Schaerer, Daniel [Université de Toulouse, UPS-OMP, IRAP, F-31000 Toulouse (France); Verhamme, Anne; Orlitová, Ivana [Geneva Observatory, University of Geneva, 51 Chemin des Maillettes, CH-1290 Versoix (Switzerland); Mas-Hesse, J. Miguel; Otí-Floranes, Héctor [Centro de Astrobiología (CSIC-INTA), Departamento de Astrofísica, P.O. Box 78, E-28691 Villanueva de la Cañada (Spain); Cannon, John M.; Pardy, Stephen [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Atek, Hakim [Laboratoire dAstrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire, CH-1290 Sauverny (Switzerland); Kunth, Daniel [Institut d' Astrophysique de Paris, UMR 7095, CNRS and UPMC, 98 bis Bd Arago, F-75014 Paris (France); Laursen, Peter [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Herenz, E. Christian, E-mail: matthew@astro.su.se [Leibniz-Institut für Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany)

2014-02-10

We report new results regarding the Lyα output of galaxies, derived from the Lyman Alpha Reference Sample, and focused on Hubble Space Telescope imaging. For 14 galaxies we present intensity images in Lyα, Hα, and UV, and maps of Hα/Hβ, Lyα equivalent width (EW), and Lyα/Hα. We present Lyα and UV radial light profiles and show they are well-fitted by Sérsic profiles, but Lyα profiles show indices systematically lower than those of the UV (n ≈ 1-2 instead of ≳ 4). This reveals a general lack of the central concentration in Lyα that is ubiquitous in the UV. Photometric growth curves increase more slowly for Lyα than the far ultraviolet, showing that small apertures may underestimate the EW. For most galaxies, however, flux and EW curves flatten by radii ≈10 kpc, suggesting that if placed at high-z only a few of our galaxies would suffer from large flux losses. We compute global properties of the sample in large apertures, and show total Lyα luminosities to be independent of all other quantities. Normalized Lyα throughput, however, shows significant correlations: escape is found to be higher in galaxies of lower star formation rate, dust content, mass, and nebular quantities that suggest harder ionizing continuum and lower metallicity. Six galaxies would be selected as high-z Lyα emitters, based upon their luminosity and EW. We discuss the results in the context of high-z Lyα and UV samples. A few galaxies have EWs above 50 Å, and one shows f{sub esc}{sup Lyα} of 80%; such objects have not previously been reported at low-z.

The Lyman alpha reference sample. II. Hubble space telescope imaging results, integrated properties, and trends

International Nuclear Information System (INIS)

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

2014-01-01

We report new results regarding the Lyα output of galaxies, derived from the Lyman Alpha Reference Sample, and focused on Hubble Space Telescope imaging. For 14 galaxies we present intensity images in Lyα, Hα, and UV, and maps of Hα/Hβ, Lyα equivalent width (EW), and Lyα/Hα. We present Lyα and UV radial light profiles and show they are well-fitted by Sérsic profiles, but Lyα profiles show indices systematically lower than those of the UV (n ≈ 1-2 instead of ≳ 4). This reveals a general lack of the central concentration in Lyα that is ubiquitous in the UV. Photometric growth curves increase more slowly for Lyα than the far ultraviolet, showing that small apertures may underestimate the EW. For most galaxies, however, flux and EW curves flatten by radii ≈10 kpc, suggesting that if placed at high-z only a few of our galaxies would suffer from large flux losses. We compute global properties of the sample in large apertures, and show total Lyα luminosities to be independent of all other quantities. Normalized Lyα throughput, however, shows significant correlations: escape is found to be higher in galaxies of lower star formation rate, dust content, mass, and nebular quantities that suggest harder ionizing continuum and lower metallicity. Six galaxies would be selected as high-z Lyα emitters, based upon their luminosity and EW. We discuss the results in the context of high-z Lyα and UV samples. A few galaxies have EWs above 50 Å, and one shows f esc Lyα of 80%; such objects have not previously been reported at low-z.

CONSTRAINING DUST AND MOLECULAR GAS PROPERTIES IN Lyα BLOBS AT z ∼ 3

International Nuclear Information System (INIS)

Yang Yujin; Decarli, Roberto; Walter, Fabian; Leipski, Christian; Dannerbauer, Helmut; Le Floc'h, Emeric; Weiss, Axel; Menten, Karl M.; Dey, Arjun; Chapman, Scott C.; Prescott, Moire K. M.; Neri, Roberto; Borys, Colin; Matsuda, Yuichi; Yamada, Toru; Hayashino, Tomoki; Tapken, Christian

2012-01-01

In order to constrain the bolometric luminosities, dust properties, and molecular gas content of giant Lyα nebulae, the so-called Lyα blobs, we have carried out a study of dust continuum and CO line emission in two well-studied representatives of this population at z ∼ 3: an Lyα blob discovered by its strong Spitzer Multiband Infrared Photometer 24 μm detection (LABd05) and the Steidel blob 1 (SSA22-LAB01). We find that the spectral energy distribution of LABd05 is well described by an active-galactic-nucleus-starburst composite template with L FIR = (4.0 ± 0.5) × 10 12 L ☉ , comparable to high-z submillimeter galaxies and ultraluminous infrared galaxies. New Large APEX Bolometer Camera 870 μm measurements rule out the reported Submillimeter Common-User Bolometer Array detection of the SSA22-LAB01 (S 850μm = 16.8 mJy) at the >4σ level. Consistent with this, ultradeep Plateau de Bure Interferometer observations with ∼2'' spatial resolution also fail to detect any 1.2 mm continuum source down to ≈0.45 mJy beam –1 (3σ). Combined with the existing (sub)millimeter observations in the literature, we conclude that the FIR luminosity of SSA22-LAB01 remains uncertain. No CO line is detected in either case down to integrated flux limits of S ν ΔV ∼ –1 , indicating a modest molecular gas reservoir, M(H 2 ) 10 M ☉ . The non-detections exclude, with high significance (12σ), the previous tentative detection of a CO J = 4-3 line in the SSA22-LAB01. The increased sensitivity afforded by the Atacama Large Millimeter/submillimeter Array will be critical in studying molecular gas and dust in these interesting systems.

Specific binding of (/sup 3/H)LY186126, an analogue of indolidan (LY195115), to cardiac membranes enriched in sarcoplasmic reticulum vesicles

Energy Technology Data Exchange (ETDEWEB)

Kauffman, R.F.; Utterback, B.G.; Robertson, D.W.

1989-05-01

LY186126 was found to be a potent inhibitor of type IV cyclic AMP phosphodiesterase located in the sarcoplasmic reticulum of canine cardiac muscle. This compound, a close structural analogue of indolidan (LY195115), was prepared in high specific activity, tritiated form to study the positive inotropic receptor(s) for cardiotonic phosphodiesterase inhibitors such as indolidan and milrinone. A high-affinity binding site for (/sup 3/H)LY186126 was observed (Kd = 4 nM) in purified preparations of canine cardiac sarcoplasmic reticulum vesicles. Binding was proportional to vesicle protein, was inactivated by subjecting membranes to proteolysis or boiling, and was dependent on added Mg2+. Scatchard analysis suggested the presence of a single class of binding sites in the membrane preparation. Indolidan, milrinone, and LY186126 (all at 1 microM) produced essentially complete displacement of bound (/sup 3/H)LY186126, while nifedipine, propranolol, and prazosin had little or no effect at this concentration. This represents the first reported use of a radioactive analogue to label the inotropic receptor for cardiotonic phosphodiesterase inhibitors. The results suggest that (/sup 3/H)LY186126 is a useful radioligand for examining the subcellular site(s) responsible for positive inotropic effects of these drugs.

Joint Bayesian Estimation of Quasar Continua and the Lyα Forest Flux Probability Distribution Function

Science.gov (United States)

Eilers, Anna-Christina; Hennawi, Joseph F.; Lee, Khee-Gan

2017-08-01

We present a new Bayesian algorithm making use of Markov Chain Monte Carlo sampling that allows us to simultaneously estimate the unknown continuum level of each quasar in an ensemble of high-resolution spectra, as well as their common probability distribution function (PDF) for the transmitted Lyα forest flux. This fully automated PDF regulated continuum fitting method models the unknown quasar continuum with a linear principal component analysis (PCA) basis, with the PCA coefficients treated as nuisance parameters. The method allows one to estimate parameters governing the thermal state of the intergalactic medium (IGM), such as the slope of the temperature-density relation γ -1, while marginalizing out continuum uncertainties in a fully Bayesian way. Using realistic mock quasar spectra created from a simplified semi-numerical model of the IGM, we show that this method recovers the underlying quasar continua to a precision of ≃ 7 % and ≃ 10 % at z = 3 and z = 5, respectively. Given the number of principal component spectra, this is comparable to the underlying accuracy of the PCA model itself. Most importantly, we show that we can achieve a nearly unbiased estimate of the slope γ -1 of the IGM temperature-density relation with a precision of +/- 8.6 % at z = 3 and +/- 6.1 % at z = 5, for an ensemble of ten mock high-resolution quasar spectra. Applying this method to real quasar spectra and comparing to a more realistic IGM model from hydrodynamical simulations would enable precise measurements of the thermal and cosmological parameters governing the IGM, albeit with somewhat larger uncertainties, given the increased flexibility of the model.

LY-354740 (Eli Lilly).

Science.gov (United States)

Pilc, Andrzej

2003-01-01

Lilly is developing LY-354740, the lead compound in a series of derivatives of the metabotropic glutamate receptor group II agonist L-CCG-1, for the potential treatment of anxiety [212536], [276941], [276942].

High-Reflectivity Multi-Layer Coatings for the CLASP Sounding Rocket Project

Science.gov (United States)

Narukage, Noriyuki; Kano, Ryohei; Bando, Takamasa; Ishikawa, Ryoko; Kubo, Masahito; Katsukawa, Yukio; Ishikawa, Shin-nosuke; Kobiki, Toshihiko; Giono, Gabriel; Auchere, Frederic;

Giant Ly α Nebulae in the Illustris Simulation

Energy Technology Data Exchange (ETDEWEB)

Gronke, Max [Institute of Theoretical Astrophysics, University of Oslo, Postboks 1029 Blindern, NO-0315 Oslo (Norway); Bird, Simeon, E-mail: maxbg@astro.uio.no [Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218 (United States)

2017-02-01

Several “giant” Ly α nebulae with an extent ≳300 kpc and observed Ly α luminosity of ≳10{sup 44} erg s{sup −1} cm{sup −2} arcsec{sup −2} have recently been detected, and it has been speculated that their presence hints at a substantial cold gas reservoir in small cool clumps not resolved in modern hydrodynamical simulations. We use the Illustris simulation to predict the Ly α emission emerging from large halos ( M > 10{sup 11.5} M {sub ⊙}) at z ∼ 2 and thus test this model. We consider both active galactic nucleus (AGN) and star driven ionization, and compare the simulated surface brightness maps, profiles, and Ly α spectra to a model where most gas is clumped below the simulation resolution scale. We find that with Illustris, no additional clumping is necessary to explain the extents, luminosities, and surface brightness profiles of the “giant Ly α nebulae” observed. Furthermore, the maximal extents of the objects show a wide spread for a given luminosity and do not correlate significantly with any halo properties. We also show how the detected size depends strongly on the employed surface brightness cutoff, and predict that further examples of such objects will be found in the near future.

TensorLy: Tensor Learning in Python

OpenAIRE

Kossaifi, Jean; Panagakis, Yannis; Pantic, Maja

2016-01-01

Tensors are higher-order extensions of matrices. While matrix methods form the cornerstone of machine learning and data analysis, tensor methods have been gaining increasing traction. However, software support for tensor operations is not on the same footing. In order to bridge this gap, we have developed \\emph{TensorLy}, a high-level API for tensor methods and deep tensorized neural networks in Python. TensorLy aims to follow the same standards adopted by the main projects of the Python scie...

CHARGE-EXCHANGE LIMITS ON LOW-ENERGY {alpha}-PARTICLE FLUXES IN SOLAR FLARES

Energy Technology Data Exchange (ETDEWEB)

Hudson, H. S. [SSL, UC Berkeley, CA 94720 (United States); Fletcher, L.; MacKinnon, A. L. [School of Physics and Astronomy, SUPA, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Woods, T. N., E-mail: hhudson@ssl.berkeley.edu [Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Dr., Boulder, CO 80303 (United States)

2012-06-20

This paper reports on a search for flare emission via charge-exchange radiation in the wings of the Ly{alpha} line of He II at 304 A, as originally suggested for hydrogen by Orrall and Zirker. Via this mechanism a primary {alpha} particle that penetrates into the neutral chromosphere can pick up an atomic electron and emit in the He II bound-bound spectrum before it stops. The Extreme-ultraviolet Variability Experiment on board the Solar Dynamics Observatory gives us our first chance to search for this effect systematically. The Orrall-Zirker mechanism has great importance for flare physics because of the essential roles that particle acceleration plays; this mechanism is one of the few proposed that would allow remote sensing of primary accelerated particles below a few MeV nucleon{sup -1}. We study 10 events in total, including the {gamma}-ray events SOL2010-06-12 (M2.0) and SOL2011-02-24 (M3.5) (the latter a limb flare), seven X-class flares, and one prominent M-class event that produced solar energetic particles. The absence of charge-exchange line wings may point to a need for more complete theoretical work. Some of the events do have broadband signatures, which could correspond to continua from other origins, but these do not have the spectral signatures expected from the Orrall-Zirker mechanism.

Time-Resolved Ultraviolet Spectroscopy of The M-Dwarf GJ 876 Exoplanetary System

Science.gov (United States)

France, Kevin; Linsky, Jeffrey L.; Tian, Feng; Froning, Cynthia S.; Roberge, Aki

2012-01-01

Extrasolar planets orbiting M-stars may represent our best chance to discover habitable worlds in the coming decade. The ultraviolet spectrum incident upon both Earth-like and Jovian planets is critically important for proper modeling of their atmospheric heating and chemistry. In order to provide more realistic inputs for atmospheric models of planets orbiting low-mass stars, we present new near- and far-ultraviolet (NUV and FUV) spectroscopy of the M-dwarf exoplanet host GJ 876 (M4V). Using the COS and STIS spectrographs on board the Hubble Space Telescope, we have measured the 1150-3140 A spectrum of GJ 876. We have reconstructed the stellar H1 Ly alpha emission line profile, and find that the integrated Ly alpha flux is roughly equal to the rest of the integrated flux (1150-1210 A + 1220-3140 A) in the entire ultraviolet bandpass (F(Ly alpha)/F(FUV+NUV) equals approximately 0.7). This ratio is approximately 2500x greater than the solar value. We describe the ultraviolet line spectrum and report surprisingly strong fluorescent emission from hot H2 (T(H2) greater than 2000 K). We show the light curve of a chromospheric + transition region flare observed in several far-UV emission lines, with flare/quiescent flux ratios greater than or equal to 10. The strong FUV radiation field of an M-star (and specifically Ly alpha) is important for determining the abundance of O2--and the formation of biomarkers-in the lower atmospheres of Earth-like planets in the habitable zones of low-mass stars.

Extinction Correction Significantly Influences the Estimate of the Lyα Escape Fraction

Science.gov (United States)

An, Fang Xia; Zheng, Xian Zhong; Hao, Cai-Na; Huang, Jia-Sheng; Xia, Xiao-Yang

2017-02-01

The Lyα escape fraction is a key measure to constrain the neutral state of the intergalactic medium and then to understand how the universe was fully reionized. We combine deep narrowband imaging data from the custom-made filter NB393 and the {{{H}}}2S1 filter centered at 2.14 μm to examine the Lyα emitters and Hα emitters at the same redshift z = 2.24. The combination of these two populations allows us to determine the Lyα escape fraction at z = 2.24. Over an area of 383 arcmin2 in the Extended Chandra Deep Field South (ECDFS), 124 Lyα emitters are detected down to NB393 = 26.4 mag at the 5σ level, and 56 Hα emitters come from An et al. Of these, four have both Lyα and Hα emissions (LAHAEs). We also collect the Lyα emitters and Hα emitters at z = 2.24 in the COSMOS field from the literature, and increase the number of LAHAEs to 15 in total. About one-third of them are AGNs. We measure the individual/volumetric Lyα escape fraction by comparing the observed Lyα luminosity/luminosity density to the extinction-corrected Hα luminosity/luminosity density. We revisit the extinction correction for Hα emitters using the Galactic extinction law with color excess for nebular emission. We also adopt the Calzetti extinction law together with an identical color excess for stellar and nebular regions to explore how the uncertainties in extinction correction affect the estimate of individual and global Lyα escape fractions. In both cases, an anti-correlation between the Lyα escape fraction and dust attenuation is found among the LAHAEs, suggesting that dust absorption is responsible for the suppression of the escaping Lyα photons. However, the estimated Lyα escape fraction of individual LAHAEs varies by up to ˜3 percentage points between the two methods of extinction correction. We find the global Lyα escape fraction at z = 2.24 to be (3.7 ± 1.4)% in the ECDFS. The variation in the color excess of the extinction causes a discrepancy of ˜1 percentage point

Targeting PI3K-AKT-mTOR by LY3023414 inhibits human skin squamous cell carcinoma cell growth in vitro and in vivo.

Science.gov (United States)

Zou, Ying; Ge, Minggai; Wang, Xuemin

2017-08-19

Abnormal activation of PI3K-AKT-mTOR signaling is detected in human skin squamous cell carcinoma (SCC). LY3023414 is a novel, potent, and orally bio-available PI3K-AKT-mTOR inhibitor. Its activity against human skin SCC cells was tested. We demonstrated that LY3023414 was cytotoxic when added to established (A431 line) and primary (patient-derived) human skin SCC cells. LY3023414 induced G0/1-S arrest and inhibited proliferation of skin SCC cells. Moreover, LY3023414 induced activation of caspase-3/-9 and apoptosis in skin SCC cells. Intriguingly, LY3023414 was yet non-cytotoxic nor pro-apoptotic to normal human skin cells (melanocytes, keratinocytes and fibroblasts). At the molecular level, LY3023414 blocked PI3K-AKT-mTOR activation in skin SCC cells, as it dephosphorylated PI3K-AKT-mTOR substrates: P85, AKT and S6K1. In vivo studies showed that oral administration of LY3023414 at well-tolerated doses inhibited A431 xenograft tumor growth in severe combined immunodeficiency (SCID) mice. AKT-mTOR activation in LY3023414-treated tumors was also largely inhibited. Together, these results suggest that targeting PI3K-AKT-mTOR by LY3023414 inhibits human skin SCC cell growth in vitro and in vivo, establishing the rationale for further clinical testing. Copyright © 2017 Elsevier Inc. All rights reserved.

Comparing the Antiseizure and Neuroprotective Efficacy of LY293558, Diazepam, Caramiphen, and LY293558-Caramiphen Combination against Soman in a Rat Model Relevant to the Pediatric Population

Science.gov (United States)

Apland, James P.; Aroniadou-Anderjaska, Vassiliki; Figueiredo, Taiza H.; Pidoplichko, Volodymyr I.; Rossetti, Katia

2018-01-01

The currently Food and Drug Administration–approved anticonvulsant for the treatment of status epilepticus (SE) induced by nerve agents is the benzodiazepine diazepam; however, diazepam does not appear to offer neuroprotective benefits. This is of particular concern with respect to the protection of children because, in the developing brain, synaptic transmission mediated via GABAA receptors, the target of diazepam, is weak. In the present study, we exposed 21-day-old male rats to 1.2 × LD50 soman and compared the antiseizure, antilethality, and neuroprotective efficacy of diazepam (10 mg/kg), LY293558 (an AMPA/GluK1 receptor antagonist; 15 mg/kg), caramiphen (CRM, an antimuscarinic with NMDA receptor-antagonistic properties; 50 mg/kg), and LY293558 (15 mg/kg) + CRM (50 mg/kg), administered 1 hour after exposure. Diazepam, LY293558, and LY293558 + CRM, but not CRM alone, terminated SE; LY293558 + CRM treatment acted significantly faster and produced a survival rate greater than 85%. Thirty days after soman exposure, neurodegeneration in limbic regions was most severe in the CRM-treated group, minimal to severe—depending on the region—in the diazepam group, absent to moderate in the LY293558-treated group, and totally absent in the LY293558 + CRM group. Amygdala and hippocampal atrophy, a severe reduction in spontaneous inhibitory activity in the basolateral amygdala, and increased anxiety-like behavior in the open-field and acoustic startle response tests were present in the diazepam and CRM groups, whereas the LY293558 and LY293558 + CRM groups did not differ from controls. The combined administration of LY293558 and CRM, by blocking mainly AMPA, GluK1, and NMDA receptors, is a very effective anticonvulsant and neuroprotective therapy against soman in young rats. PMID:29467308

Comparing the Antiseizure and Neuroprotective Efficacy of LY293558, Diazepam, Caramiphen, and LY293558-Caramiphen Combination against Soman in a Rat Model Relevant to the Pediatric Population.

Science.gov (United States)

Apland, James P; Aroniadou-Anderjaska, Vassiliki; Figueiredo, Taiza H; Pidoplichko, Volodymyr I; Rossetti, Katia; Braga, Maria F M

2018-05-01

The currently Food and Drug Administration-approved anticonvulsant for the treatment of status epilepticus (SE) induced by nerve agents is the benzodiazepine diazepam; however, diazepam does not appear to offer neuroprotective benefits. This is of particular concern with respect to the protection of children because, in the developing brain, synaptic transmission mediated via GABA A receptors, the target of diazepam, is weak. In the present study, we exposed 21-day-old male rats to 1.2 × LD 50 soman and compared the antiseizure, antilethality, and neuroprotective efficacy of diazepam (10 mg/kg), LY293558 (an AMPA/GluK1 receptor antagonist; 15 mg/kg), caramiphen (CRM, an antimuscarinic with NMDA receptor-antagonistic properties; 50 mg/kg), and LY293558 (15 mg/kg) + CRM (50 mg/kg), administered 1 hour after exposure. Diazepam, LY293558, and LY293558 + CRM, but not CRM alone, terminated SE; LY293558 + CRM treatment acted significantly faster and produced a survival rate greater than 85%. Thirty days after soman exposure, neurodegeneration in limbic regions was most severe in the CRM-treated group, minimal to severe-depending on the region-in the diazepam group, absent to moderate in the LY293558-treated group, and totally absent in the LY293558 + CRM group. Amygdala and hippocampal atrophy, a severe reduction in spontaneous inhibitory activity in the basolateral amygdala, and increased anxiety-like behavior in the open-field and acoustic startle response tests were present in the diazepam and CRM groups, whereas the LY293558 and LY293558 + CRM groups did not differ from controls. The combined administration of LY293558 and CRM, by blocking mainly AMPA, GluK1, and NMDA receptors, is a very effective anticonvulsant and neuroprotective therapy against soman in young rats. U.S. Government work not protected by U.S. copyright.

THE BARYON OSCILLATION SPECTROSCOPIC SURVEY OF SDSS-III

Energy Technology Data Exchange (ETDEWEB)

Dawson, Kyle S.; Ahn, Christopher P.; Bolton, Adam S. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Schlegel, David J.; Bailey, Stephen [Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720 (United States); Anderson, Scott F.; Bhardwaj, Vaishali [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Aubourg, Eric; Bautista, Julian E. [APC, University of Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cite (France); Barkhouser, Robert H. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Beifiori, Alessandra [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Berlind, Andreas A. [Department of Physics and Astronomy, Vanderbilt University, VU Station 1807, Nashville, TN 37235 (United States); Bizyaev, Dmitry; Brewington, Howard [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States); Blake, Cullen H. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Blanton, Michael R. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Blomqvist, Michael [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Borde, Arnaud [CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette (France); Bovy, Jo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Brandt, W. N., E-mail: kdawson@astro.utah.edu [Department of Astronomy and Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802 (United States); and others

2013-01-01

The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in the clustering of matter over a larger volume than the combined efforts of all previous spectroscopic surveys of large-scale structure. BOSS uses 1.5 million luminous galaxies as faint as i = 19.9 over 10,000 deg{sup 2} to measure BAO to redshifts z < 0.7. Observations of neutral hydrogen in the Ly{alpha} forest in more than 150,000 quasar spectra (g < 22) will constrain BAO over the redshift range 2.15 < z < 3.5. Early results from BOSS include the first detection of the large-scale three-dimensional clustering of the Ly{alpha} forest and a strong detection from the Data Release 9 data set of the BAO in the clustering of massive galaxies at an effective redshift z = 0.57. We project that BOSS will yield measurements of the angular diameter distance d{sub A} to an accuracy of 1.0% at redshifts z = 0.3 and z = 0.57 and measurements of H(z) to 1.8% and 1.7% at the same redshifts. Forecasts for Ly{alpha} forest constraints predict a measurement of an overall dilation factor that scales the highly degenerate D{sub A} (z) and H {sup -1}(z) parameters to an accuracy of 1.9% at z {approx} 2.5 when the survey is complete. Here, we provide an overview of the selection of spectroscopic targets, planning of observations, and analysis of data and data quality of BOSS.

Radial-velocity variations in Alpha Ori, Alpha Sco, and Alpha Her

International Nuclear Information System (INIS)

Smith, M.A.; Patten, B.M.; Goldberg, L.

1989-01-01

Radial-velocity observations of Alpha Ori, Alpha Sco A, and Alpha Her A are used to study radial-velocity periodicities in M supergiants. The data refer to several metallic lines in the H-alpha region and to H-alpha itself. It is shown that Alpha Ori and Alpha Sco A have cycle lengths of about 1 yr and semiamplitudes of 2 km/s. It is suggested that many semiregular red supergiant varibles such as Alpha Ori may be heading toward chaos. All three stars show short-term stochastic flucutations with an amplitude of 1-2 km/s. It is found that the long-term variability of H-alpha velocities may be a consequence of intermittent failed ejections. 58 refs

Observation of X-ray lines from a gamma-ray burst (GRB991216): evidence of moving ejecta from the progenitor.

Science.gov (United States)

Piro, L; Garmire, G; Garcia, M; Stratta, G; Costa, E; Feroci, M; Mészáros, P; Vietri, M; Bradt, H; Frail, D; Frontera, F; Halpern, J; Heise, J; Hurley, K; Kawai, N; Kippen, R M; Marshall, F; Murakami, T; Sokolov, V V; Takeshima, T; Yoshida, A

2000-11-03

We report on the discovery of two emission features observed in the x-ray spectrum of the afterglow of the gamma-ray burst (GRB) of 16 December 1999 by the Chandra X-ray Observatory. These features are identified with the Ly(alpha) line and the narrow recombination continuum by hydrogenic ions of iron at a redshift z = 1.00 +/- 0.02, providing an unambiguous measurement of the distance of a GRB. Line width and intensity imply that the progenitor of the GRB was a massive star system that ejected, before the GRB event, a quantity of iron approximately 0.01 of the mass of the sun at a velocity approximately 0.1 of the speed of light, probably by a supernova explosion.

Line broadening analysis of implosion core conditions at Z using argon K-shell spectroscopy

International Nuclear Information System (INIS)

Burris-Mog, T.J.; Mancini, R.C.; Bailey, J.E.; Chandler, G.A.; Rochau, G.; Dunham, G.; Lake, P.W.; Peterson, K.; Slutz, S.A.; Mehlhorn, T.A.; Golovkin, I.E.; MacFarlane, J.J.

2006-01-01

We report on spectral line broadening analysis of Ar K-shell lines from argon-doped implosion cores driven by a dynamic hohlraum z-pinch. The observed Ar spectra include emissions from the resonance series in H- and He-like Ar ions, i.e., Lyα, Lyβ and Lyγ, and Heα, Heβ, Heγ and Heδ lines, respectively. The analysis accounts for opacity and Stark broadening to determine electron density, N e , and areal-density, NΔR, values for the ground state populations of H- and He-like Ar ions. Furthermore, these results are combined with the ratio of H- and He-like ground state populations to extract the electron temperature, T e

Line officers' views on stated USDA Forest Service values and the agency reward system.

Science.gov (United States)

James J. Kennedy; Richard W. Haynes; Xiaoping Zhou

2005-01-01

To update and expand a study done in 1989 (Kennedy et al. 1992), we surveyed line officers attending the third National Forest Supervisors’ Conference (Chief, Associate Chief, deputy chiefs, regional foresters, directors of International Institute of Tropical Forestry and State and Private Forestry Northeastern Area, and forest supervisors; January 2004) and a 40-...

HUBBLE SPACE TELESCOPE IMAGING OF Lyα EMISSION AT z ∼ 4.4

International Nuclear Information System (INIS)

Finkelstein, Steven L.; Finkelstein, Keely D.; Cohen, Seth H.; Windhorst, Rogier A.; Malhotra, Sangeeta; Rhoads, James E.; Ryan, Russell E.; Hathi, Nimish P.; McCarthy, Patrick J.; Anderson, Jay; Grogin, Norman A.; Koekemoer, Anton M.; Mutchler, Max; Bond, Howard E.; O'Connell, Robert W.; Balick, Bruce; Calzetti, Daniela; Disney, Michael J.; Dopita, Michael A.; Frogel, Jay A.

2011-01-01

We present the highest redshift detections of resolved Lyα emission, using Hubble Space Telescope (HST)/Advanced Camera for Surveys F658N narrowband-imaging data taken in parallel with the Wide Field Camera 3 Early Release Science program in the GOODS Chandra Deep Field-South. We detect Lyα emission from three spectroscopically confirmed z = 4.4 Lyα emitting galaxies (LAEs), more than doubling the sample of LAEs with resolved Lyα emission. Comparing the light distribution between the rest-frame ultraviolet continuum and narrowband images, we investigate the escape of Lyα photons at high redshift. While our data do not support a positional offset between the Lyα and rest-frame ultraviolet (UV) continuum emission, the half-light radius in one out of the three galaxies is significantly (>1σ) larger in Lyα than in the rest-frame UV continuum. Stacking the three LAEs in both the narrowband and UV continuum images, we find that the Lyα light appears larger than the rest-frame UV at 4.2σ significance. This Lyα flux detected with HST is a factor of 4-10 less than observed in similar filters from the ground. These results together imply that the Lyα emission is not strictly confined to its indigenous star-forming regions. Rather, for at least one object the Lyα emission is more extended, with the missing HST flux possibly existing in a diffuse outer halo. This suggests that the radiative transfer of Lyα photons in high-redshift LAEs is complicated, with the interstellar-medium geometry and/or outflows playing a significant role in galaxies at these redshifts.

In vivo assay for conversion of testosterone to dihydrotestosterone by rat prostatic steroid 5 alpha-reductase and comparison of two inhibitors

International Nuclear Information System (INIS)

Toomey, R.E.; Goode, R.L.; Petrow, V.; Neubauer, B.L.

1991-01-01

An in vivo assay for steroid 5 alpha-reductase in rat ventral prostate has been developed and used to compare the inhibitory activity of N,N-diethyl-4-methyl-3-oxo-4-aza-5 alpha-androstane-17 beta-carboxamide (4-MA) and 6-methylene-4-pregnene-3,20-dione (LY207320). Immature rats (70-80 g) received test compounds 30 min prior to s.c. injection of [3H]-T. The rats were sacrificed 30 min later and the ventral prostates were analyzed for [3H]-T metabolites. Intraprostatic [3H]-T and [3H]-DHT reached peak levels within 5 min after injection of [3H]-T and declined to about 25% of peak levels after 2 hr. 4-MA was a very potent inhibitor of [3H]-DHT formation with an estimated IC50 of 0.2 mg/kg. LY207320, an inhibitor of 5 alpha-reductase in vitro, was weakly active in vivo and did not achieve greater than 45% inhibition at high doses (greater than 200 mg/kg, s.c.). Tissue uptake of [3H]-T was also inhibited by LY207320, which may contribute to its inhibitory activity on accessory sex organ growth in the rat

DEVELOPMENT OF AN ON-LINE, REAL-TIME ALPHA RADIATION MEASURING INSTRUMENT FOR LIQUID STREAMS

International Nuclear Information System (INIS)

Unknown

1999-01-01

Thermo Power Corporation has proven the technical viability of an on-line, real-time alpha radionuclide instrument for aqueous sample analysis through laboratory and initial field tests of the instrument. The instrument has been shown to be isotonically sensitive to extremely low (ten parts per trillion, or femto Curies per liter) levels of a broad range of radioisotopes. Performance enhancement and other scaling data obtained during the course of this investigation have shown that on-line, real-time operation is possible, with a sub 30-minute response time analyzing 20 ppb (30 pCi/1) natural uranium. Now that these initial field tests in Oak Ridge, Tennessee have been successfully completed, Thermo Power plans to conduct comprehensive field tests of the instrument. The purpose of these endurance tests will be to determine the endurance characteristics of the Thermo Alpha Monitor for Water when it is used by non-Thermo Power personnel in a series of one or more extended field tests. Such endurance testing is the vital next step towards the commercialization of the Alpha Monitor. Subsequently, it will be possible to provide the DOE with an instrument that has the capability of obtaining rapid feedback about the concentrations of alpha-emitting isotope contamination in effluent water streams (Subsurface Contaminants Focus Area). It will also be useful for process control of remediation and D and D operations such as monitoring scrubber/rinse water radioactivity levels (Mixed Waste, Plutonium and D and D Focus Areas)

Dark energy and curvature from a future baryonic acoustic oscillation survey using the Lyman-α forest

International Nuclear Information System (INIS)

McDonald, Patrick; Eisenstein, Daniel J.

2007-01-01

We explore the requirements for a Lyman-α forest survey designed to measure the angular diameter distance and Hubble parameter at 2 or approx. 250 spectrograph is sufficient to measure both the radial and transverse oscillation scales to 1.4% from the Lyα forest (or better, if fainter magnitudes and possibly Lyman-break galaxies can be used). At fixed integration time and in the sky-noise-dominated limit, a wider, noisier survey is generally more efficient; the only fundamental upper limit on noise being the need to identify a quasar and find a redshift. Because the Lyα forest is much closer to linear and generally better understood than galaxies, systematic errors are even less likely to be a problem

Ly49Q, an ITIM-bearing NK receptor, positively regulates osteoclast differentiation

International Nuclear Information System (INIS)

Hayashi, Mikihito; Nakashima, Tomoki; Kodama, Tatsuhiko; Makrigiannis, Andrew P.; Toyama-Sorimachi, Noriko; Takayanagi, Hiroshi

2010-01-01

Osteoclasts, multinucleated cells that resorb bone, play a key role in bone remodeling. Although immunoreceptor tyrosine-based activation motif (ITAM)-mediated signaling is critical for osteoclast differentiation, the significance of immunoreceptor tyrosine-based inhibitory motif (ITIM) has not been well understood. Here we report the function of Ly49Q, an Ly49 family member possessing an ITIM motif, in osteoclastogenesis. Ly49Q is selectively induced by receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL) stimulation in bone marrow-derived monocyte/macrophage precursor cells (BMMs) among the Ly49 family of NK receptors. The knockdown of Ly49Q resulted in a significant reduction in the RANKL-induced formation of tartrate-resistance acid phosphatase (TRAP)-positive multinucleated cells, accompanied by a decreased expression of osteoclast-specific genes such as Nfatc1, Tm7sf4, Oscar, Ctsk, and Acp5. Osteoclastogenesis was also significantly impaired in Ly49Q-deficient cells in vitro. The inhibitory effect of Ly49Q-deficiency may be explained by the finding that Ly49Q competed for the association of Src-homology domain-2 phosphatase-1 (SHP-1) with paired immunoglobulin-like receptor-B (PIR-B), an ITIM-bearing receptor which negatively regulates osteoclast differentiation. Unexpectedly, Ly49Q deficiency did not lead to impaired osteoclast formation in vivo, suggesting the existence of a compensatory mechanism. This study provides an example in which an ITIM-bearing receptor functions as a positive regulator of osteoclast differentiation.

Diagnosing the reionization of the universe - The absorption spectrum of the intergalactic medium and Lyman alpha clouds

Science.gov (United States)

Giroux, Mark L.; Shapiro, Paul R.

1991-01-01

The thermal and ionization evolution of a uniform intergalactic medium composed of H and He and undergoing reionization is studied. The diagnosis of the metagalactic ionizing radiation background at z of about three using metal line ratios for Lyman limit quasar absorption line systems is addressed. The use of the He II Gunn-Peterson effect to diagnose the reionization source and/or nature of the Hy-alpha forest clouds is considered.

The b Distribution and the Velocity Structure of Absorption Peaks in the Lyα Forest

International Nuclear Information System (INIS)

Hui, L.; Rutledge, R.E.

1999-01-01

A theory is developed that relates the observed b parameter of a Lyα absorption line to the velocity curvature of the corresponding peak in the optical depth fluctuation. Its relation to the traditional interpretation of b as the thermal broadening width is discussed. It is demonstrated that, independent of the details of the cosmological model, the differential b distribution has a high-b asymptote of dN/db∝b -m , where m≥5, when we make the reasonable assumption that low-curvature fluctuations are statistically favored over high-curvature ones. There in general always exist lines much broader than the thermal width. We develop a linear perturbative analysis of the optical depth fluctuation, which yields a single-parameter prediction for the full b distribution. In addition to exhibiting the high-velocity tail, it qualitatively explains the observed sharp low-b cutoff a simple reflection of the fact that high-curvature fluctuations are relatively rare. Although the existence of the high-b asymptote, which is independent of the validity of the linear expansion, is consistent with the observed b distribution, a detailed comparison of the linear prediction with six observational data sets indicates that higher order corrections are not negligible. The perturbative analysis nonetheless offers valuable insights into the dependence of the b distribution on cosmological parameters such as Ω and the power spectrum. A key parameter is the effective smoothing scale of the optical depth fluctuation, which is in turn determined by three scales: the thermal broadening width, the baryon smoothing scale (approximately the Jeans scale), and the observation/simulation resolution. The first two are determined by reionization history, but are comparable in general, whereas the third varies by about an order of magnitude in current hydrodynamic simulations. Studies with non resolution-dominated b distributions can be used to probe the reionization history of the universe

9-AAA inhibits growth and induces apoptosis in human melanoma A375 and rat prostate adenocarcinoma AT-2 and Mat-LyLu cell lines but does not affect the growth and viability of normal fibroblasts.

Science.gov (United States)

Korohoda, Włodzimierz; Hapek, Anna; Pietrzak, Monika; Ryszawy, Damian; Madeja, Zbigniew

2016-11-01

The present study found that, similarly to 5-fluorouracil, low concentrations (1-10 µM) of 9-aminoacridine (9-AAA) inhibited the growth of the two rat prostate cancer AT-2 and Mat-LyLu cell lines and the human melanoma A375 cell line. However, at the same concentrations, 9-AAA had no effect on the growth and apoptosis of normal human skin fibroblasts (HSFs). The differences between the cellular responses of the AT-2 and Mat-LyLu cell lines, which differ in malignancy, were found to be relatively small compared with the differences between normal HSFs and the cancer cell lines. Visible effects on the cell growth and survival of tumor cell lines were observed after 24-48 h of treatment with 9-AAA, and increased over time. The inhibition of cancer cell growth was found to be due to the gradually increasing number of cells dying by apoptosis, which was observed using two methods, direct counting and FlowSight analysis. Simultaneously, cell motile activity decreased to the same degree in cancer and normal cells within the first 8 h of incubation in the presence of 9-AAA. The results presented in the current study suggest that short-lasting tests for potential anticancer substances can be insufficient; which may result in cell type-dependent differences in the responses of cells to tested compounds that act with a delay being overlooked. The observed differences in responses between normal human fibroblasts and cancer cells to 9-AAA show the requirement for additional studies to be performed simultaneously on differently reacting cancer and normal cells, to determine the molecular mechanisms responsible for these differences.

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

Science.gov (United States)

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

2018-05-01

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

1alpha-hydroxylase and innate immune responses to 25-hydroxyvitamin D in colonic cell lines.

Science.gov (United States)

Lagishetty, Venu; Chun, Rene F; Liu, Nancy Q; Lisse, Thomas S; Adams, John S; Hewison, Martin

2010-07-01

Vitamin D-insufficiency is a prevalent condition in populations throughout the world, with low serum levels of 25-hydroxyvitamin D (25OHD) linked to a variety of human health concerns including cancer, autoimmune disease and infection. Current data suggest that 25OHD action involves localized extra-renal conversion to 1,25-dihydroxyvitamin D (1,25(OH)2D) via tissue-specific expression of the enzyme 25-hydroxyvitamin D-1alpha-hydroxylase (1alpha-hydroxylase). In cells such as macrophages, expression of 1alpha-hydroxylase is intimately associated with toll-like receptor (TLR) recognition of pathogens. However, this mechanism may not be exclusive to extra-renal generation of 1,25(OH)2D. To investigate the relationship between TLR-mediated pathogen recognition and vitamin D-induced antibacterial activity, intracrine responses to 25OHD metabolism were explored in vitro using the established colonic cell lines Caco-2 and Caco-2 clone BBe. Analysis of antibacterial factors such as cathelicidin (LL37) and beta-defensin-4 (DEFB4) was carried out following co-treatment with TLR ligands. Data indicate that, unlike macrophages, Caco-2 and BBe colonic cell lines are unresponsive to TLR-induced 1alpha-hydroxylase. Alternative activators of 1alpha-hydroxylase such as transforming growth factor beta were also ineffective at priming intracrine responses to 25OHD. Thus, in common with other barrier sites such as the skin or placenta, colonic epithelial cells may require specific factors to initiate intracrine responses to vitamin D. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Alternative splicing of T cell receptor (TCR) alpha chain transcripts containing V alpha 1 or V alpha 14 elements.

Science.gov (United States)

Mahotka, C; Hansen-Hagge, T E; Bartram, C R

1995-10-01

Human acute lymphoblastic leukemia cell lines represent valuable tools to investigate distinct steps of the complex regulatory pathways underlying T cell receptor recombination and expression. A case in point are V delta 2D delta 3 and subsequent V delta 2D delta 3J alpha rearrangements observed in human leukemic pre-B cells as well as in normal lymphopoiesis. The functional expression of these unusual (VD) delta (JC) alpha hybrids is almost exclusively prevented by alternative splicing events. In this report we show that alternative splicing at cryptic splice donor sites within V elements is not a unique feature of hybrid TCR delta/alpha transcripts. Among seven V alpha families analyzed by RT-PCR, alternatively spliced products were observed in TCR alpha recombinations containing V alpha 1 or V alpha 14 elements. In contrast to normal peripheral blood cells and thymocytes, the leukemia cell line JM expressing functional V alpha 1J alpha 3C alpha transcripts lacked evidence of aberrant TCR alpha RNA species.

Inspiraling halo accretion mapped in Ly α emission around a z ˜ 3 quasar

Science.gov (United States)

Arrigoni Battaia, Fabrizio; Prochaska, J. Xavier; Hennawi, Joseph F.; Obreja, Aura; Buck, Tobias; Cantalupo, Sebastiano; Dutton, Aaron A.; Macciò, Andrea V.

2018-01-01

In an effort to search for Ly α emission from circum- and intergalactic gas on scales of hundreds of kpc around z ∼ 3 quasars, and thus characterize the physical properties of the gas in emission, we have initiated an extensive fast survey with the Multi-Unit Spectroscopic Explorer (MUSE): Quasar Snapshot Observations with MUse: Search for Extended Ultraviolet eMission (QSO MUSEUM). In this work, we report the discovery of an enormous Ly α nebula (ELAN) around the quasar SDSS J102009.99+104002.7 at z = 3.164, which we followed-up with deeper MUSE observations. This ELAN spans ∼297 projected kpc, has an average Ly α surface brightness SBLy α ∼ 6.04 × 10-18 erg s-1 cm-2 arcsec-2(within the 2σ isophote) and is associated with an additional four previously unknown embedded sources: two Ly α emitters and two faint active galactic nuclei (one type-1 and one type-2 quasar). By mapping at high significance, the line-of-sight velocity in the entirety of the observed structure, we unveiled a large-scale coherent rotation-like pattern spanning ∼300 km s-1 with a velocity dispersion of <270 km s-1, which we interpret as a signature of the inspiraling accretion of substructures within the quasar's host halo. Future multiwavelength data will complement our MUSE observations and are definitely needed to fully characterize such a complex system. None the less, our observations reveal the potential of new sensitive integral-field spectrographs to characterize the dynamical state of diffuse gas on large scales in the young Universe, and thereby witness the assembly of galaxies.

LYα FOREST TOMOGRAPHY FROM BACKGROUND GALAXIES: THE FIRST MEGAPARSEC-RESOLUTION LARGE-SCALE STRUCTURE MAP AT z > 2

Energy Technology Data Exchange (ETDEWEB)

Lee, Khee-Gan; Hennawi, Joseph F.; Eilers, Anna-Christina [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Stark, Casey; White, Martin [Department of Astronomy, University of California at Berkeley, B-20 Hearst Field Annex 3411, Berkeley, CA 94720 (United States); Prochaska, J. Xavier [Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Schlegel, David J. [University of California Observatories, Lick Observatory, 1156 High Street, Santa Cruz, CA 95064 (United States); Arinyo-i-Prats, Andreu [Institut de Ciències del Cosmos, Universitat de Barcelona (IEEC-UB), Martí Franquès 1, E-08028 Barcelona (Spain); Suzuki, Nao [Kavli Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo, Kashiwano-ha 5-1-5, Kashiwa-shi, Chiba (Japan); Croft, Rupert A. C. [Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); Caputi, Karina I. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700-AV Groningen (Netherlands); Cassata, Paolo [Instituto de Fisica y Astronomia, Facultad de Ciencias, Universidad de Valparaiso, Av. Gran Bretana 1111, Casilla 5030, Valparaiso (Chile); Ilbert, Olivier; Le Brun, Vincent; Le Fèvre, Olivier [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Garilli, Bianca [INAF-IASF, Via Bassini 15, I-20133, Milano (Italy); Koekemoer, Anton M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Maccagni, Dario [INAF-Osservatorio Astronomico di Bologna, Via Ranzani,1, I-40127 Bologna (Italy); Nugent, Peter, E-mail: lee@mpia.de [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); and others

2014-11-01

We present the first observations of foreground Lyα forest absorption from high-redshift galaxies, targeting 24 star-forming galaxies (SFGs) with z ∼ 2.3-2.8 within a 5' × 14' region of the COSMOS field. The transverse sightline separation is ∼2 h {sup –1} Mpc comoving, allowing us to create a tomographic reconstruction of the three-dimensional (3D) Lyα forest absorption field over the redshift range 2.20 ≤ z ≤ 2.45. The resulting map covers 6 h {sup –1} Mpc × 14 h {sup –1} Mpc in the transverse plane and 230 h {sup –1} Mpc along the line of sight with a spatial resolution of ≈3.5 h {sup –1} Mpc, and is the first high-fidelity map of a large-scale structure on ∼Mpc scales at z > 2. Our map reveals significant structures with ≳ 10 h {sup –1} Mpc extent, including several spanning the entire transverse breadth, providing qualitative evidence for the filamentary structures predicted to exist in the high-redshift cosmic web. Simulated reconstructions with the same sightline sampling, spectral resolution, and signal-to-noise ratio recover the salient structures present in the underlying 3D absorption fields. Using data from other surveys, we identified 18 galaxies with known redshifts coeval with our map volume, enabling a direct comparison with our tomographic map. This shows that galaxies preferentially occupy high-density regions, in qualitative agreement with the same comparison applied to simulations. Our results establish the feasibility of the CLAMATO survey, which aims to obtain Lyα forest spectra for ∼1000 SFGs over ∼1 deg{sup 2} of the COSMOS field, in order to map out the intergalactic medium large-scale structure at (z) ∼ 2.3 over a large volume (100 h {sup –1} Mpc){sup 3}.

THE NATURE OF Lyα BLOBS: POWERED BY EXTREME STARBURSTS

International Nuclear Information System (INIS)

Cen, Renyue; Zheng, Zheng

2013-01-01

We present a new model for the observed Lyα blobs (LABs) within the context of the standard cold dark matter model. In this model, LABs are the most massive halos with the strongest clustering (protoclusters) undergoing extreme starbursts in the high-z universe. Aided by calculations of detailed radiative transfer of Lyα photons through ultrahigh resolution (159 pc), large-scale (≥30 Mpc) adaptive mesh refinement cosmological hydrodynamic simulations with galaxy formation, this model is shown to be able to, for the first time, reproduce simultaneously the global Lyα luminosity function and the luminosity-size relation of the observed LABs. Physically, a combination of dust attenuation of Lyα photons within galaxies, clustering of galaxies, and the complex propagation of Lyα photons through the circumgalactic and intergalactic medium gives rise to the large sizes and the irregular isophotal shapes of LABs that are frequently observed. A generic and unique prediction of this model is that there should be strong far-infrared (FIR) sources within each LAB with the most luminous FIR source likely representing the gravitational center of the protocluster, not necessarily the apparent center of the Lyα emission of the LAB or the most luminous optical source. Upcoming ALMA observations should unambiguously test this prediction. If verified, LABs will provide very valuable laboratories for studying the formation of galaxies in the most overdense regions of the universe at a time when the global star formation was the most vigorous

The Nature of Lyα Blobs: Powered by Extreme Starbursts

Science.gov (United States)

Cen, Renyue; Zheng, Zheng

2013-10-01

We present a new model for the observed Lyα blobs (LABs) within the context of the standard cold dark matter model. In this model, LABs are the most massive halos with the strongest clustering (protoclusters) undergoing extreme starbursts in the high-z universe. Aided by calculations of detailed radiative transfer of Lyα photons through ultrahigh resolution (159 pc), large-scale (>=30 Mpc) adaptive mesh refinement cosmological hydrodynamic simulations with galaxy formation, this model is shown to be able to, for the first time, reproduce simultaneously the global Lyα luminosity function and the luminosity-size relation of the observed LABs. Physically, a combination of dust attenuation of Lyα photons within galaxies, clustering of galaxies, and the complex propagation of Lyα photons through the circumgalactic and intergalactic medium gives rise to the large sizes and the irregular isophotal shapes of LABs that are frequently observed. A generic and unique prediction of this model is that there should be strong far-infrared (FIR) sources within each LAB with the most luminous FIR source likely representing the gravitational center of the protocluster, not necessarily the apparent center of the Lyα emission of the LAB or the most luminous optical source. Upcoming ALMA observations should unambiguously test this prediction. If verified, LABs will provide very valuable laboratories for studying the formation of galaxies in the most overdense regions of the universe at a time when the global star formation was the most vigorous.

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.

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

International Nuclear Information System (INIS)

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

2017-01-01

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

Hydrogen Balmer alpha intensity distributions and line profiles from multiple scattering theory using realistic geocoronal models

Science.gov (United States)

Anderson, D. E., Jr.; Meier, R. R.; Hodges, R. R., Jr.; Tinsley, B. A.

1987-01-01

The H Balmer alpha nightglow is investigated by using Monte Carlo models of asymmetric geocoronal atomic hydrogen distributions as input to a radiative transfer model of solar Lyman-beta radiation in the thermosphere and atmosphere. It is shown that it is essential to include multiple scattering of Lyman-beta radiation in the interpretation of Balmer alpha airglow data. Observations of diurnal variation in the Balmer alpha airglow showing slightly greater intensities in the morning relative to evening are consistent with theory. No evidence is found for anything other than a single sinusoidal diurnal variation of exobase density. Dramatic changes in effective temperature derived from the observed Balmer alpha line profiles are expected on the basis of changing illumination conditions in the thermosphere and exosphere as different regions of the sky are scanned.

Probing the Intergalactic Medium with Ly α and 21 cm Fluctuations

Energy Technology Data Exchange (ETDEWEB)

Heneka, Caroline [Dark Cosmology Center, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Cooray, Asantha; Feng, Chang [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)

2017-10-10

We study 21 cm and Ly α fluctuations, as well as H α , while distinguishing between Ly α emission of galactic, diffuse, and scattered intergalactic medium (IGM) origin. Cross-correlation information about the state of the IGM is obtained, testing neutral versus ionized medium cases with different tracers in a seminumerical simulation setup. In order to pave the way toward constraints on reionization history and modeling beyond power spectrum information, we explore parameter dependencies of the cross-power signal between 21 cm and Ly α , which displays a characteristic morphology and a turnover from negative to positive correlation at scales of a couple Mpc{sup −1}. In a proof of concept for the extraction of further information on the state of the IGM using different tracers, we demonstrate the use of the 21 cm and H α cross-correlation signal to determine the relative strength of galactic and IGM emission in Ly α . We conclude by showing the detectability of the 21 cm and Ly α cross-correlation signal over more than one decade in scale at high signal-to-noise ratio for upcoming probes like SKA and the proposed all-sky intensity mapping satellites SPHEREx and CDIM, while also including the Ly α damping tail and 21 cm foreground avoidance in the modeling.

Irradiation of bone lining cells from bone-seeking alpha-emitters

International Nuclear Information System (INIS)

Kruglikov, I.; Polig, E.

1993-01-01

The influence of bone remodeling and the non-uniform distribution of alpha-emitters on the hit statistics is discussed. It is shown that for the first generation of bone lining cells, bone remodeling decreases the probability of no hits to the nuclei of these cells whereas the randomness of the spatial distribution of nuclide increases this probability. For the subsequent generations bone remodeling as well as spatial distribution of nuclide increase the probability of no hits. The most conservative estimations for the variance of hits and probability of no hits, which are defined by the minimums of these values, are obtained. (orig.)

Vitamin E analogue, D-alpha tocopherol succinate, enhances x-ray induced growth delay of human adenocarcinoma cancer cell line

International Nuclear Information System (INIS)

Jaworska, A.; Ottesen, T.E.

2003-01-01

The purpose of this study was to assess the effects of d-alpha Tocopherol succinate (alpha-TS) in modifying radiation-induced viability reduction and apoptosis occurrence in the model for normal and cancer cells. Our hypothesis was that alpha-TS enhances the growth-inhibitory effect of x-irradiation in cancer cells and that the effect is more pronounced in these cells than in normal cells. Murine NIH 3T3 Swiss albino embryonic cells and HT29 human Caucasian colon adenocarcinoma cells were used in the experiments. Alpha-TS was added to the cultures 1 h prior to irradiation with doses of 2 or 5Gy of x-ray. After irradiation cells were incubated for 73 h. Trypan blue exclusion viability test and estimation of apoptosis and necrosis were made. Apoptotic and necrotic cells were counted in fluorescence microscope using fluorescence dyes: propidium iodide and Hoechst 33342. For experiments with the dose of 5 Gy at least five series of experiments were performed. At lower doses (up to approximately 25μM/ml) treatment with alpha-TS alone enhanced growth of both cell lines. At higher doses treatment with alpha-TS alone delayed the growth of the cell cultures, accompanied by 20-25% necrosis. At the concentrations higher than 25μM/mL alpha-TS alone caused growth delay of both cell cultures, being much more pronounced for the cancer cell line HT29. At the concentrations of 50 μM/mL, responsible for about 30-60% of growth delay, there was observed a synergy effect for x-rays and alpha-TS for both cell lines. The effect was more pronounced for HT29 cells (DMF=0.48 for HT29 versus DMF=0.73 for NIH 3T3). These results may confirm the views of the literature reports suggesting that use of vitamin E together with radiation could be favorable for colon cancer treatment; however, more experiments using more advanced techniques are needed

Raw data from the Italian National Forest Inventory are on-line and publicly available

Directory of Open Access Journals (Sweden)

Borghetti M

2016-12-01

Full Text Available Raw data from the Italian National Forest Inventory are on-line and publicly available. The National Forest Service in cooperation with the Forest Monitoring and Management Research Unit of the Council for Agricultural Research and Economics (CREA released the raw data from the National Inventory of Forests and forest Carbon pools - INFC2005 project, the second Italian national forest inventory. Data are available together with metadata information at http://www.inventarioforestale.org/. Users, after registration, can download data from 230.874 living tree stems, 16.472 dead tree stems, 31.083 stumps, from a total of 7.272 field plots (for 1.384 of them additional data on fine woody debris and soil carbon pools are also available.

Influence of Projection Operator on Oxygen Line Shapes and its effect on Rosseland-Mean Opacity in Stellar Interiors

Science.gov (United States)

Gomez, Thomas; Nagayama, Taisukue; Kilcrease, David; Hansen, Stephanie; Montgomery, Mike; Winget, Don

2018-01-01

The Rosseland-Mean opacity (RMO) is an important quantity in determining radiation transport through stars. The solar-convection-zone boundary predicted by the standard solar model disagrees with helioseismology measurements by many sigma; a 14% increase in the RMO would resolve this discrepancy. Experiments at Sandia National Laboratories are now measuring iron opacity at solar-interior conditions, and significant discrepancies are already observed. Highly-ionized oxygen is one of the dominant contributions to the RMO. The strongest line, Lyman alpha, is at the peak of the Rosseland weighting function. The accuracy of line-broadening calculations has been called into question due to various experimental results and comparisons between theory. We have developed an ab-initio calculation to explore different physical effects, our current focus is treating penetrating collisions explicitly. The equation of motion used to calculate line shapes within the relaxation and unified theories includes a projection operator, which performs an average over plasma electron states; this is neglected due to past calculations approximate treatment of penetrations. We now include this projection term explicitly, which results in a significant broadening of spectral lines from highly-charged ions (low-Z elements are not much affected). The additional broadening raises the O Ly-alpha wing opacity by a factor of 5; we examine the consequences of this additional broadening on the Rosseland mean.

Constraining the Intergalactic and Circumgalactic Media with Lyman-Alpha Absorption

Science.gov (United States)

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

2018-01-01

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

The CALYMHA survey: Lyα escape fraction and its dependence on galaxy properties at z = 2.23

Science.gov (United States)

Matthee, Jorryt; Sobral, David; Oteo, Iván; Best, Philip; Smail, Ian; Röttgering, Huub; Paulino-Afonso, Ana

2016-05-01

We present the first results from our CAlibrating LYMan α with Hα (CALYMHA) pilot survey at the Isaac Newton Telescope. We measure Lyα emission for 488 Hα selected galaxies at z = 2.23 from High-z Emission Line Survey in the COSMOS and UDS fields with a specially designed narrow-band filter (λc = 3918 Å, Δλ = 52 Å). We find 17 dual Hα-Lyα emitters [fLyα > 5 × 10-17 erg s-1 cm-2, of which five are X-ray active galactic nuclei (AGN)]. For star-forming galaxies, we find a range of Lyα escape fractions (fesc, measured with 3 arcsec apertures) from 2 to 30 per cent. These galaxies have masses from 3 × 108 M⊙ to 1011 M⊙ and dust attenuations E(B - V) = 0-0.5. Using stacking, we measure a median escape fraction of 1.6 ± 0.5 per cent (4.0 ± 1.0 per cent without correcting Hα for dust), but show that this depends on galaxy properties. The stacked fesc tends to decrease with increasing star formation rate and dust attenuation. However, at the highest masses and dust attenuations, we detect individual galaxies with fesc much higher than the typical values from stacking, indicating significant scatter in the values of fesc. Relations between fesc and UV slope are bimodal, with high fesc for either the bluest or reddest galaxies. We speculate that this bimodality and large scatter in the values of fesc is due to additional physical mechanisms such as outflows facilitating fesc for dusty/massive systems. Lyα is significantly more extended than Hα and the UV. fesc continues to increase up to at least 20 kpc (3σ, 40 kpc [2σ]) for typical star-forming galaxies and thus the aperture is the most important predictor of fesc.

A Survey of Metal Lines at High Redshift. II. SDSS Absorption Line Studies—O VI Line Density, Space Density, and Gas Metallicity at z abs ~ 3.0

Science.gov (United States)

Frank, S.; Mathur, S.; Pieri, M.; York, D. G.

2010-09-01

We have analyzed a large data set of O VI absorber candidates found in the spectra of 3702 Sloan Digital Sky Survey (SDSS) quasars, focusing on a subsample of 387 active galactic nuclei sight lines with an average S/N >=5.0, allowing for the detection of absorbers above a rest-frame equivalent width limit of W r >= 0.19 Å for the O VI 1032 Å component. Accounting for random interlopers mimicking an O VI doublet, we derive for the first time a secure lower limit for the redshift number density ΔN/Δz for redshifts z abs >= 2.8. With extensive Monte Carlo simulations, we quantify the losses of absorbers due to blending with the ubiquitous Lyα forest lines and estimate the success rate of retrieving each individual candidate as a function of its redshift, the emission redshift of the quasar, the strength of the absorber, and the measured signal-to-noise ratio (S/N) of the spectrum by modeling typical Lyman forest spectra. These correction factors allow us to derive the "incompleteness and S/N-corrected" redshift number densities of O VI absorbers: ΔN O VI,c /Δzc (2.8 secure lower limit for the contribution of O VI to the closure mass density at the redshifts probed here: ΩO VI (2.8 = 1.9 × 10-8 h -1. We show that the strong lines we probe account for over 65% of the mass in the O VI absorbers; the weak absorbers, while dominant in line number density, do not contribute significantly to the mass density. Making a conservative assumption about the ionization fraction, {O VI}/{O}, and adopting the Anders & Grevesse solar abundance values, we derive the mean metallicity of the gas probed in our search: ζ(2.8 = 3.6 × 10-4 h, in good agreement with other studies. These results demonstrate that large spectroscopic data sets such as SDSS can play an important role in QSO absorption line studies, in spite of the relatively low resolution.

A SURVEY OF METAL LINES AT HIGH REDSHIFT. II. SDSS ABSORPTION LINE STUDIES-O VI LINE DENSITY, SPACE DENSITY, AND GAS METALLICITY AT zabs ∼ 3.0

International Nuclear Information System (INIS)

Frank, S.; Mathur, S.; Pieri, M.; York, D. G.

2010-01-01

We have analyzed a large data set of O VI absorber candidates found in the spectra of 3702 Sloan Digital Sky Survey (SDSS) quasars, focusing on a subsample of 387 active galactic nuclei sight lines with an average S/N ≥5.0, allowing for the detection of absorbers above a rest-frame equivalent width limit of W r ≥ 0.19 A for the O VI 1032 A component. Accounting for random interlopers mimicking an O VI doublet, we derive for the first time a secure lower limit for the redshift number density ΔN/Δz for redshifts z abs ≥ 2.8. With extensive Monte Carlo simulations, we quantify the losses of absorbers due to blending with the ubiquitous Lyα forest lines and estimate the success rate of retrieving each individual candidate as a function of its redshift, the emission redshift of the quasar, the strength of the absorber, and the measured signal-to-noise ratio (S/N) of the spectrum by modeling typical Lyman forest spectra. These correction factors allow us to derive the 'incompleteness and S/N-corrected' redshift number densities of O VI absorbers: ΔN O V I,c /Δz c (2.8 O V I,c /Δz c (3.2 O V I,c /Δz c (3.6 O V I (2.8 -8 h -1 . We show that the strong lines we probe account for over 65% of the mass in the O VI absorbers; the weak absorbers, while dominant in line number density, do not contribute significantly to the mass density. Making a conservative assumption about the ionization fraction, O VI /O, and adopting the Anders and Grevesse solar abundance values, we derive the mean metallicity of the gas probed in our search: ζ(2.8 -4 h, in good agreement with other studies. These results demonstrate that large spectroscopic data sets such as SDSS can play an important role in QSO absorption line studies, in spite of the relatively low resolution.

The Discovery of a Luminous Z=5.80 Quasar from the Sloan Digital Sky Survey

Science.gov (United States)

Fan, Xiaohui; White, Richard L.; Davis, Marc; Becker, Robert H.; Strauss, Michael A.; Haiman, Zoltan; Schneider, Donald P.; Gregg, Michael D.; Gunn, James E.; Knapp, G. R.; Lupton, Robert H.; Anderson, John E., Jr.; Anderson, Scott F.; Annis, James; Bahcall, Neta A.; Boroski, William N.; Brunner, Robert J.; Chen, Bing; Connolly, Andrew J.; Csabai, István; Doi, Mamoru; Fukugita, Masataka; Hennessy, G. S.; Hindsley, Robert B.; Ichikawa, Takashi; Ivezić, Željko; Loveday, Jon; Meiksin, Avery; McKay, Timothy A.; Munn, Jeffrey A.; Newberg, Heidi Jo; Nichol, Robert; Okamura, Sadanori; Pier, Jeffrey R.; Sekiguchi, Maki; Shimasaku, Kazuhiro; Stoughton, Chris; Szalay, Alexander S.; Szokoly, Gyula P.; Thakar, Aniruddha R.; Vogeley, Michael S.; York, Donald G.

2000-09-01

We present observations of SDSSp J104433.04-012502.2, a luminous quasar at z=5.80 discovered from Sloan Digital Sky Survey (SDSS) multicolor imaging data. This object was selected as an i'-band dropout object, with i*=21.8+/-0.2 and z*=19.2+/-0.1. It has an absolute magnitude M1450=-27.2 (H0=50 km s-1 Mpc-1, q0=0.5). The spectrum shows a strong and broad Lyα emission line, strong Lyα forest absorption lines with a mean continuum decrement DA=0.91 and a Lyman limit system at z=5.72. The spectrum also shows strong O I and Si IV emission lines similar to those of quasars at zuniverse is already highly ionized at z~5.8. Using a high-resolution spectrum in the Lyα forest region, we place a conservative upper limit on the optical depth because of the Gunn-Peterson effect of τUniversity of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation.

For-LySa: UML for Authentication Analysis

DEFF Research Database (Denmark)

Buchholtz, Mikael; Montangero, Carlo; Perrone, Lara

2005-01-01

The DEGAS project aims at enriching standard UML-centred development environments in such a way that the developers of global applications can exploit automated formal analyses with minimal overhead. In this paper, we present For-LySa, an instantiation of the DEGAS approach for authentication...... analysis, which exploits an existing analysis tool developed for the process calculus LySa. We discuss what information is needed for the analysis, and how to build the UML model of an authentication protocol in such a way that the needed information can be extracted from the model. We then present our...

Synthesis of multidrug resistance modulator LY335979 labeled with deuterium and tritium

International Nuclear Information System (INIS)

Czeskis, B.A.

1997-01-01

DIDEUTERO AND DITRITIOISOTOPOMERS OF THE MULTIDRUG RESISTANCE MODULATOR LY335979 WERE PREPARED BY INITIAL BROMINATION OF 5-HYDROXYQUINOLINE UNDER ACIDIC CONDITIONS FOLLOWED BY MITSUNOBU COUPLING OF 6,8-DIBROMO-5-HYDROXYQUINOLINE WITH (S)-GLYCIDOL. OPENING OF THE RESULTING EPOXIDE WITH DIBENZOSUBERYLPIPERAZINE LY335995 RESULTED IN DIBROMOANALOG OF LY335979, WHICH WAS FINALLY REDUCTIVELY DEBROMINATED WITH DEUTERIUM OR TRITIUM IN THE PRESENCE OF PALLADIUM ON CARBON. (AUTHOR)

Beta3 subunits promote expression and nicotine-induced up-regulation of human nicotinic alpha6* nicotinic acetylcholine receptors expressed in transfected cell lines.

Science.gov (United States)

Tumkosit, Prem; Kuryatov, Alexander; Luo, Jie; Lindstrom, Jon

2006-10-01

Nicotinic acetylcholine receptors (AChRs) containing alpha6 subunits are typically found at aminergic nerve endings where they play important roles in nicotine addiction and Parkinson's disease. alpha6* AChRs usually contain beta3 subunits. beta3 subunits are presumed to assemble only in the accessory subunit position within AChRs where they do not participate in forming acetylcholine binding sites. Assembly of subunits in the accessory position may be a critical final step in assembly of mature AChRs. Human alpha6 AChRs subtypes were permanently transfected into human tsA201 human embryonic kidney (HEK) cell lines. alpha6beta2beta3 and alpha6beta4beta3 cell lines were found to express much larger amounts of AChRs and were more sensitive to nicotine-induced increase in the amount of AChRs than were alpha6beta2 or alpha6beta4 cell lines. The increased sensitivity to nicotine-induced up-regulation was due not to a beta3-induced increase in affinity for nicotine but probably to a direct effect on assembly of AChR subunits. HEK cells express only a small amount of mature alpha6beta2 AChRs, but many of these subunits are on the cell surface. This contrasts with Xenopus laevis oocytes, which express a large amount of incorrectly assembled alpha6beta2 subunits that bind cholinergic ligands but form large amorphous intracellular aggregates. Monoclonal antibodies (mAbs) were made to the alpha6 and beta3 subunits to aid in the characterization of these AChRs. The alpha6 mAbs bind to epitopes C-terminal of the extracellular domain. These data demonstrate that both cell type and the accessory subunit beta3 can play important roles in alpha6* AChR expression, stability, and up-regulation by nicotine.

Ly6G-mediated depletion of neutrophils is dependent on macrophages.

Science.gov (United States)

Bruhn, Kevin W; Dekitani, Ken; Nielsen, Travis B; Pantapalangkoor, Paul; Spellberg, Brad

2016-01-01

Antibody-mediated depletion of neutrophils is commonly used to study neutropenia. However, the mechanisms by which antibodies deplete neutrophils have not been well defined. We noticed that mice deficient in complement and macrophages had blunted neutrophil depletion in response to anti-Ly6G monoclonal antibody (MAb) treatment. In vitro, exposure of murine neutrophils to anti-Ly6G MAb in the presence of plasma did not result in significant depletion of cells, either in the presence or absence of complement. In vivo, anti-Ly6G-mediated neutrophil depletion was abrogated following macrophage depletion, but not complement depletion, indicating a requirement for macrophages to induce neutropenia by this method. These results inform the use and limitations of anti-Ly6G antibody as an experimental tool for depleting neutrophils in various immunological settings.

ORIGIN OF THE GALACTIC DIFFUSE X-RAY EMISSION: IRON K-SHELL LINE DIAGNOSTICS

Energy Technology Data Exchange (ETDEWEB)

Nobukawa, Masayoshi [Department of Teacher Training and School Education, Nara University of Education, Takabatake-cho, Nara, 630-8528 (Japan); Uchiyama, Hideki [Faculty of Education, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529 (Japan); Nobukawa, Kumiko K.; Koyama, Katsuji [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake-cho, Sakyo-ku, Kyoto, 606-8502 (Japan); Yamauchi, Shigeo, E-mail: nobukawa@nara-edu.ac.jp [Department of Physics, Nara Women’s University, Kitauoyanishimachi, Nara, 630-8506 (Japan)

2016-12-20

This paper reports detailed K-shell line profiles of iron (Fe) and nickel (Ni) of the Galactic Center X-ray Emission (GCXE), Galactic Bulge X-ray Emission (GBXE), Galactic Ridge X-ray Emission (GRXE), magnetic Cataclysmic Variables (mCVs), non-magnetic Cataclysmic Variables (non-mCVs), and coronally Active Binaries (ABs). For the study of the origin of the GCXE, GBXE, and GRXE, the spectral analysis is focused on equivalent widths of the Fe i-K α , Fe xxv-He α , and Fe xxvi-Ly α  lines. The global spectrum of the GBXE is reproduced by a combination of the mCVs, non-mCVs, and ABs spectra. On the other hand, the GRXE spectrum shows significant data excesses at the Fe i-K α and Fe xxv-He α  line energies. This means that additional components other than mCVs, non-mCVs, and ABs are required, which have symbiotic phenomena of cold gas and very high-temperature plasma. The GCXE spectrum shows larger excesses than those found in the GRXE spectrum at all the K-shell lines of iron and nickel. Among them the largest ones are the Fe i-K α , Fe xxv-He α , Fe xxvi-Ly α , and Fe xxvi-Ly β  lines. Together with the fact that the scale heights of the Fe i-K α , Fe xxv-He α , and Fe xxvi-Ly α lines are similar to that of the central molecular zone (CMZ), the excess components would be related to high-energy activity in the extreme envelopment of the CMZ.

MAPPING THE POLARIZATION OF THE RADIO-LOUD Ly α NEBULA B3 J2330+3927

International Nuclear Information System (INIS)

You, Chang; Zabludoff, Ann; Smith, Paul; Jannuzi, Buell; Yang, Yujin; Kim, Eunchong; Lee, Myung Gyoon; Prescott, Moire K. M.; Matsuda, Yuichi

2017-01-01

Ly α nebulae, or “Ly α blobs,” are extended (up to ∼100 kpc), bright (L Lyα  ≳ 10 43 erg s −1 ) clouds of Ly α emitting gas that tend to lie in overdense regions at z  ∼ 2–5. The origin of the Ly α emission remains unknown, but recent theoretical work suggests that measuring the polarization might discriminate among powering mechanisms. Here we present the first narrowband imaging polarimetry of a radio-loud Ly α nebula, B3 J2330+3927, at z = 3.09, with an embedded active galactic nucleus (AGN). The AGN lies near the blob’s Ly α emission peak, and its radio lobes align roughly with the blob’s major axis. With the SPOL polarimeter on the 6.5 m MMT telescope, we map the total (Ly α + continuum) polarization in a grid of circular apertures of a radius of 0.″6 (4.4 kpc), detecting a significant (>2 σ ) polarization fraction P % in nine apertures and achieving strong upper limits (as low as 2%) elsewhere. P % increases from <2% at ∼5 kpc from the blob center to 17% at ∼15–25 kpc. The detections are distributed asymmetrically, roughly along the nebula’s major axis. The polarization angles θ are mostly perpendicular to this axis. Comparing the Ly α flux to that of the continuum and conservatively assuming that the continuum is highly polarized (20%–100%) and aligned with the total polarization, we place lower limits on the polarization of the Ly α emission P %,Lyα ranging from no significant polarization at ∼5 kpc from the blob center to 3%–17% at 10–25 kpc. Like the total polarization, the Ly α polarization detections occur more often along the blob’s major axis.

The role of autophagy inhibition in the enhanced cytotoxicity of temozolomide on melanoma cell lines

Directory of Open Access Journals (Sweden)

O. O. Ryabaya

2017-01-01

Full Text Available Background. Despite advantages in treatment of metastatic melanoma it remains resistant to current therapy. Recent evidence indicates that tumor cells could overcome death through autophagy, a process that degrades cellular proteins and organelles to maintain cellular biosynthesis during nutrient deprivation or lack of energy. Objective: to investigate the involvement of autophagy inhibitors chloroquine (CQ and LY-294.002 (LY in temozolomide (TMZ cytotoxicity in human melanoma cell lines.Materials and methods. The study was performed on patient-derived melanoma cell lines Mel Z, Mel IL and Mel MTP. The antiproliferative activity of combined TMZ and autophagy inhibitors treatment was determined by MTT assay and colony-forming assay. Cell cycle analysis, apoptosis activation and expression analysis of key autophagy markers under combined treatment was evaluated.Results. CQ and LY enhanced the cytotoxicity of TMZ and reduced colony formation in 3 melanoma cell lines, moreover both inhibitors increased cell population in G0 / G1 phase of cell cycle in Mel Z, Mel IL cell lines, but not in Mel MTP. CQ and LY synergistically activated apoptosis in all cell lines. The matrix RNA expression analysis of key autophagy genes showed autophagy involvement in enhanced cytotoxicity.Conclusions. Thus, autophagy inhibition on different stages of this process could overcome resistance to TMZ and be applicable as potent target in metastatic melanoma treatment.

Galaxy at a redshift of 3.215 - further studies of the PKS 1614+051 system

International Nuclear Information System (INIS)

Djorgovski, S.; Strauss, M.A.; Spinrad, H.; Mccarthy, P.; Perley, R.A.; California Univ., Berkeley; National Radio Astronomy Observatory, Charlottesville, VA)

1987-01-01

A narrow-emission-line companion of the quasar PKS 1614+051 was reported earlier as a probable galaxy at a redshift of 3.218, which would have made it by far the most distant galaxy known at the time. New radio and optical imaging, and optical and near-IR spectroscopy of the PKS 1614+051 system is reported here. It is argued that the data support and reinforce the original interpretation of the companion object as a mildly active galaxy, possibly a marginal Seyfert 2. The object has a detectable and marginally resolved optical continuum, but was not detected at radio wavelengths. The ionization state is low, and the emission lines are fairly narrow. The improved redshift for the companion, based on the Ly-alpha line alone, is 3.215 + or - 0.002. New Ly-alpha images show interesting morphology of extended emission-line gas, suggestive of a possible tidal interaction with the neighboring QSO. 24 references

Modelling the gas kinematics of an atypical Ly α emitting compact dwarf galaxy

Science.gov (United States)

Forero-Romero, Jaime E.; Gronke, Max; Remolina-Gutiérrez, Maria Camila; Garavito-Camargo, Nicolás; Dijkstra, Mark

2018-02-01

Star-forming compact dwarf galaxies (CDGs) resemble the expected pristine conditions of the first galaxies in the Universe and are the best systems to test models on primordial galaxy formation and evolution. Here, we report on one of such CDGs, Tololo 1214-277, which presents a broad, single peaked, highly symmetric Ly α emission line that had evaded theoretical interpretation so far. In this paper, we reproduce for the first time these line features with two different physically motivated kinematic models: an interstellar medium composed by outflowing clumps with random motions and an homogeneous gaseous sphere undergoing solid body rotation. The multiphase model requires a clump velocity dispersion of 54.3 ± 0.6 km s-1 with outflows of 54.3 ± 5.1 km s-1 , while the bulk rotation velocity is constrained to be 348^{+75}_{-48} km s-1. We argue that the results from the multiphase model provide a correct interpretation of the data. In that case, the clump velocity dispersion implies a dynamical mass of 2 × 109 M⊙, 10 times its baryonic mass. If future kinematic maps of Tololo 1214-277 confirm the velocities suggested by the multiphase model, it would provide additional support to expect such kinematic state in primordial galaxies, opening the opportunity to use the models and methods presented in this paper to constrain the physics of star formation and feedback in the early generation of Ly α -emitting galaxies.

Spectroscopic Confirmation of Three z-dropout Galaxies at z = 6.844-7.213: Demographics of Lyα Emission in z ~ 7 Galaxies

Science.gov (United States)

Ono, Yoshiaki; Ouchi, Masami; Mobasher, Bahram; Dickinson, Mark; Penner, Kyle; Shimasaku, Kazuhiro; Weiner, Benjamin J.; Kartaltepe, Jeyhan S.; Nakajima, Kimihiko; Nayyeri, Hooshang; Stern, Daniel; Kashikawa, Nobunari; Spinrad, Hyron

2012-01-01

We present the results of our ultra-deep Keck/DEIMOS spectroscopy of z-dropout galaxies in the Subaru Deep Field and Great Observatories Origins Deep Survey's northern field. For 3 out of 11 objects, we detect an emission line at ~1 μm with a signal-to-noise ratio of ~10. The lines show asymmetric profiles with high weighted skewness values, consistent with being Lyα, yielding redshifts of z = 7.213, 6.965, and 6.844. Specifically, we confirm the z = 7.213 object in two independent DEIMOS runs with different spectroscopic configurations. The z = 6.965 object is a known Lyα emitter, IOK-1, for which our improved spectrum at a higher resolution yields a robust skewness measurement. The three z-dropouts have Lyα fluxes of 3 × 10-17 erg s-1 cm-2 and rest-frame equivalent widths EWLyα 0 = 33-43 Å. Based on the largest spectroscopic sample of 43 z-dropouts, which is the combination of our and previous data, we find that the fraction of Lyα-emitting galaxies (EWLyα 0 > 25 Å) is low at z ~ 7; 17% ± 10% and 24% ± 12% for bright (M UV ~= -21) and faint (M UV ~= -19.5) galaxies, respectively. The fractions of Lyα-emitting galaxies drop from z ~ 6 to 7 and the amplitude of the drop is larger for faint galaxies than for bright galaxies. These two pieces of evidence would indicate that the neutral hydrogen fraction of the intergalactic medium increases from z ~ 6 to 7 and that the reionization proceeds from high- to low-density environments, as suggested by an inside-out reionization model. Based on data obtained with the Subaru Telescope and the W. M. Keck Observatory. The Subaru Telescope is operated by the National Astronomical Observatory of Japan. The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration.

Line C17: alpha and medium-level beta-gamma laboratory pilot facility

International Nuclear Information System (INIS)

Calor, J.N.; Mauborgne, B.; Montuir, M.

2000-01-01

The Process Development Laboratory (LDP) uses the ATALANTE C17 line for integral testing in order to develop and validate spent fuel reprocessing methods and for overall qualification of calculation codes. Line C 17 comprises shielded cells and glove boxes, equipped with centrifugal extractors and laboratory-scale mixer-settlers to test liquid-liquid extraction processes in an alpha and medium-level beta-gamma environment. The high reliability and precision of the process instrumentation and control system allow full control of operating parameters and comprehensive operating data recording, meeting the experimentation quality requirements necessary for qualifying calculation codes. Direct online spectrophotometric analysis at various points in the process provides real-time concentration data for vital elements, some of which are difficult to analyze offline because of their poor chemical stability. Online analyses, supplemented when necessary by gamma spectrometry, provide valuable process control input for reaching stabilized operating conditions. Fifteen radioactive test campaigns have been successfully completed since line C 17 was commissioned in June 1995. (authors)

64Cu-Labeled LyP-1-Dendrimer for PET-CT Imaging of Atherosclerotic Plaque

Science.gov (United States)

2015-01-01

The ability to detect and quantify macrophage accumulation can provide important diagnostic and prognostic information for atherosclerotic plaque. We have previously shown that LyP-1, a cyclic 9-amino acid peptide, binds to p32 proteins on activated macrophages, facilitating the visualization of atherosclerotic plaque with PET. Yet, the in vivo plaque accumulation of monomeric [18F]FBA-LyP-1 was low (0.31 ± 0.05%ID/g). To increase the avidity of LyP-1 constructs to p32, we synthesized a dendritic form of LyP-1 on solid phase using lysine as the core structural element. Imaging probes (FAM or 6-BAT) were conjugated to a lysine or cysteine on the dendrimer for optical and PET studies. The N-terminus of the dendrimer was further modified with an aminooxy group in order to conjugate LyP-1 and ARAL peptides bearing a ketone. Oxime ligation of peptides to both dendrimers resulted in (LyP-1)4- and (ARAL)4-dendrimers with optical (FAM) and PET probes (6-BAT). For PET-CT studies, (LyP-1)4- and (ARAL)4-dendrimer-6-BAT were labeled with 64Cu (t1/2 = 12.7 h) and intravenously injected into the atherosclerotic (ApoE–/–) mice. After two hours of circulation, PET-CT coregistered images demonstrated greater uptake of the (LyP-1)4-dendrimer-64Cu than the (ARAL)4-dendrimer-64Cu in the aortic root and descending aorta. Ex vivo images and the biodistribution acquired at three hours after injection also demonstrated a significantly higher uptake of the (LyP-1)4-dendrimer-64Cu (1.1 ± 0.26%ID/g) than the (ARAL)4-dendrimer-64Cu (0.22 ± 0.05%ID/g) in the aorta. Similarly, subcutaneous injection of the LyP-1-dendrimeric carriers resulted in preferential accumulation in plaque-containing regions over 24 h. In the same model system, ex vivo fluorescence images within aortic plaque depict an increased accumulation and penetration of the (LyP-1)4-dendrimer-FAM as compared to the (ARAL)4-dendrimer-FAM. Taken together, the results suggest that the (LyP-1)4-dendrimer can be applied for in

Induction of DNA breakage in X-irradiated nucleoids selectively stripped of nuclear proteins in two mouse lymphoma cell lines differing in radiosensitivity

International Nuclear Information System (INIS)

Kruszewski, M.; Iwanenko, T.

1998-01-01

The role of nuclear proteins in protection of DNA against ionizing radiation and their contribution to the radiation sensitivity was examined by an alkaline version of comet assay in two L5178Y (LY) mouse lymphoma cell lines differing in sensitivity t o ionizing radiation. LY-S cells are twice more sensitive to ionizing radiation than LY-R cells (D 0 values of survival curves are 0.5 Gy and 1 Gy, respectively). Sequential removal of nuclear proteins by extraction with NaCl of different concentrations increased the X-ray induced DNA damage in LY-R nucleoids. In contrast, in the radiation sensitive LY-S cell line, depletion of nuclear proteins practically did not affect DNA damage. Although there is no doubt that the main cause of LY-S cells' sensitivity to ionizing radiation is a defect in the repair of double-strand breaks, our data support the concept that nuclear matrix organization may contribute to the cellular susceptibility to DNA damaging agents. (author)

THE HETDEX PILOT SURVEY. I. SURVEY DESIGN, PERFORMANCE, AND CATALOG OF EMISSION-LINE GALAXIES

International Nuclear Information System (INIS)

Adams, Joshua J.; Blanc, Guillermo A.; Gebhardt, Karl; Hao, Lei; Byun, Joyce; Fry, Alex; Jeong, Donghui; Komatsu, Eiichiro; Hill, Gary J.; Cornell, Mark E.; MacQueen, Phillip J.; Drory, Niv; Bender, Ralf; Hopp, Ulrich; Kelzenberg, Ralf; Ciardullo, Robin; Gronwall, Caryl; Finkelstein, Steven L.; Gawiser, Eric; Kelz, Andreas

2011-01-01

We present a catalog of emission-line galaxies selected solely by their emission-line fluxes using a wide-field integral field spectrograph. This work is partially motivated as a pilot survey for the upcoming Hobby-Eberly Telescope Dark Energy Experiment. We describe the observations, reductions, detections, redshift classifications, line fluxes, and counterpart information for 397 emission-line galaxies detected over 169 □' with a 3500-5800 A bandpass under 5 A full-width-half-maximum (FWHM) spectral resolution. The survey's best sensitivity for unresolved objects under photometric conditions is between 4 and 20x 10 -17 erg s -1 cm -2 depending on the wavelength, and Lyα luminosities between 3 x 10 42 and 6 x 10 42 erg s -1 are detectable. This survey method complements narrowband and color-selection techniques in the search of high-redshift galaxies with its different selection properties and large volume probed. The four survey fields within the COSMOS, GOODS-N, MUNICS, and XMM-LSS areas are rich with existing, complementary data. We find 105 galaxies via their high-redshift Lyα emission at 1.9 44 □' which appear to be extended Lyα nebulae. We also find three high-z objects with rest-frame Lyα EW above the level believed to be achievable with normal star formation, EW 0 >240 A. Future papers will investigate the physical properties of this sample.

MAPPING THE POLARIZATION OF THE RADIO-LOUD Ly α NEBULA B3 J2330+3927

Energy Technology Data Exchange (ETDEWEB)

You, Chang; Zabludoff, Ann; Smith, Paul; Jannuzi, Buell [Steward Observatory, University of Arizona, 933 N Cherry Avenue, Tucson, AZ 85721 (United States); Yang, Yujin [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055 (Korea, Republic of); Kim, Eunchong; Lee, Myung Gyoon [Department of Physics and Astronomy, Seoul National University, Gwanak-gu, Seoul 88226 (Korea, Republic of); Prescott, Moire K. M. [Department of Astronomy, New Mexico State University, 1320 Frenger Mall, Las Cruces, NM 88003 (United States); Matsuda, Yuichi, E-mail: yyang@kasi.re.kr [National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2017-01-10

Ly α nebulae, or “Ly α blobs,” are extended (up to ∼100 kpc), bright (L{sub Lyα}  ≳ 10{sup 43} erg s{sup −1}) clouds of Ly α emitting gas that tend to lie in overdense regions at z  ∼ 2–5. The origin of the Ly α emission remains unknown, but recent theoretical work suggests that measuring the polarization might discriminate among powering mechanisms. Here we present the first narrowband imaging polarimetry of a radio-loud Ly α nebula, B3 J2330+3927, at z = 3.09, with an embedded active galactic nucleus (AGN). The AGN lies near the blob’s Ly α emission peak, and its radio lobes align roughly with the blob’s major axis. With the SPOL polarimeter on the 6.5 m MMT telescope, we map the total (Ly α + continuum) polarization in a grid of circular apertures of a radius of 0.″6 (4.4 kpc), detecting a significant (>2 σ ) polarization fraction P {sub %} in nine apertures and achieving strong upper limits (as low as 2%) elsewhere. P{sub %} increases from <2% at ∼5 kpc from the blob center to 17% at ∼15–25 kpc. The detections are distributed asymmetrically, roughly along the nebula’s major axis. The polarization angles θ are mostly perpendicular to this axis. Comparing the Ly α flux to that of the continuum and conservatively assuming that the continuum is highly polarized (20%–100%) and aligned with the total polarization, we place lower limits on the polarization of the Ly α emission P{sub %,Lyα} ranging from no significant polarization at ∼5 kpc from the blob center to 3%–17% at 10–25 kpc. Like the total polarization, the Ly α polarization detections occur more often along the blob’s major axis.

Pharmacokinetics and pharmacodynamics of the cathepsin S inhibitor, LY3000328, in healthy subjects.

Science.gov (United States)

Payne, Christopher D; Deeg, Mark A; Chan, Melanie; Tan, Lai Hock; LaBell, Elizabeth Smith; Shen, Tong; DeBrota, David J

2014-12-01

The aim of this study was to assess the safety and tolerability, pharmacokinetics and pharmacodynamics of LY3000328 when administered as single escalating doses to healthy volunteers. This was a phase 1, placebo-controlled, dose escalation study with LY3000328 in 21 healthy male volunteers. Subjects were administered escalating LY3000328 doses up to 300 mg with food in this single dose study. Blood samples were collected at set times post-dose for the assessment of LY3000328 pharmacokinetics and the measurement of cathepsin S (CatS) activity, CatS mass and calculated CatS specific activity. All doses of LY3000328 were well tolerated, with linear pharmacokinetics up to the 300 mg dose. The pharmacodynamic activity of LY3000328 was measured ex vivo showing a biphasic response to LY3000328, where CatS activity declines, then returns to baseline, and then increases to a level above baseline. CatS mass was also assessed post-dose which increased in a dose-dependent manner, and continued to increase after LY3000328 had been cleared from the body. CatS specific activity was additionally calculated to normalize CatS activity for changes in CatS mass. This demonstrated the increase in CatS activity was attributable to the increase in CatS mass detected in plasma. A specific inhibitor of CatS which is cleared quickly from plasma may produce a transient decrease in plasma CatS activity which is followed by a more prolonged increase in plasma CatS mass which may have implications for the future clinical development of inhibitors of CatS. © 2014 The British Pharmacological Society.

Probing HeII Reionization at z>3.5 with Resolved HeII Lyman Alpha Forest Spectra

Science.gov (United States)

Worseck, Gabor

2017-08-01

The advent of GALEX and COS have revolutionized our view of HeII reionization, the final major phase transition of the intergalactic medium. COS spectra of the HeII Lyman alpha forest have confirmed with high confidence the high HeII transmission that signifies the completion of HeII reionization at z 2.7. However, the handful of z>3.5 quasars observed to date show a set of HeII transmission 'spikes' and larger regions with non-zero transmission that suggest HeII reionization was well underway by z=4. This is in striking conflict with predictions from state-of-the-art radiative transfer simulations of a HeII reionization driven by bright quasars. Explaining these measurements may require either faint quasars or more exotic sources of hard photons at z>4, with concomitant implications for HI reionization. However, many of the observed spikes are unresolved in G140L spectra and are significantly impacted by Poisson noise. Current data cannot reliably probe the ionization state of helium at z>3.5.We request 41 orbits to obtain science-grade G130M spectra of the two UV-brightest HeII-transmitting QSOs at z>3.5 to confirm and resolve their HeII transmission spikes as an unequivocal test of early HeII reionization. These spectra are complemented by recently obtained data from 8m telescopes: (1) Echelle spectra of the coeval HI Lya forest to map the underlying density field that modulates the HeII absorption, and (2) Our dedicated survey for foreground QSOs that may source the HeII transmission. Our recent HST programs revealed the only two viable targets to resolve the z>3.5 HeII Lyman alpha forest, and to conclusively solve this riddle.

Theoretical profiles of the spectral lines of the hydrogen atom; Profils theoriques des raies spectrales de l'atome d'hydrogene

Energy Technology Data Exchange (ETDEWEB)

Nguyen, H; Herman, L [Universite de la Sorbonne, Lab. de Recherche Physique, 75 - Paris (France); Drawin, H W [Commissariat a l' Energie Atomique, Fontenay-aux-Roses, Association Euratom-CEA, Groupe de Recherches sur la Fusion Controlee (France). Centre d' Etudes Nucleaires

1965-07-01

The line-broadening problem of the hydrogen lines has been formulated in the quasistatic approximation as far as the ions are concerned, and in the classical path approximation as far as the broadening due to collisions with electrons is concerned. These electrons interfere in different numerical results only by the self-correlation function of the fluctuating electrical field strength created at each point in the plasma. The Lewis correction has been applied, but using the whole velocity distribution function of the electrons. The formula which represents the usual impact profile, valid only for frequencies much smaller than the plasma frequency, has been extended using another formula which will be valid up to the neighbourhood of that spectral region where the quasi-static approximation begins to be valid also for the electrons. As an example, the line profile of Ly {alpha} is given by some graphs for T = 10{sup 4} deg. K and electron densities N = 10{sup 17} cm{sup -3} and N = 10{sup 18}cm{sup -3}. (authors) [French] Le probleme d'elargissement des raies de l'atome H est formule dans l'approximation quasi-statique en ce qui concerne les ions et dans l'approximation du chemin classique en ce qui concerne les electrons. Ceux-ci interviennent dans differents resultats uniquement par la fonction auto-correlation du champ electrique fluctuant qu'ils creent en chaque point du plasma. La correction de Lewis a ete appliquee mais en tenant compte de la distribution des vitesses electroniques. La formule donnant les profils d'impact habituels, valable seulement pour des frequences tres inferieures a la frequence du plasma, est ainsi prolongee de maniere continue par une autre formule, valable jusqu'au voisinage de la region spectrale ou l'approximation quasistatique commence a etre egalement justifiee pour les electrons. A titre d'illustration on represente graphiquement le profil de la raie Ly {alpha} pour T = 10{sup 4} deg. K et des densites electroniques de N = 10{sup

Human IgG1 Responses to Surface Localised Schistosoma mansoni Ly6 Family Members Drop following Praziquantel Treatment.

Directory of Open Access Journals (Sweden)

Iain W Chalmers

Full Text Available The heptalaminate-covered, syncytial tegument is an important anatomical adaptation that enables schistosome parasites to maintain long-term, intravascular residence in definitive hosts. Investigation of the proteins present in this surface layer and the immune responses elicited by them during infection is crucial to our understanding of host/parasite interactions. Recent studies have revealed a number of novel tegumental surface proteins including three (SmCD59a, SmCD59b and Sm29 containing uPAR/Ly6 domains (renamed SmLy6A SmLy6B and SmLy6D in this study. While vaccination with SmLy6A (SmCD59a and SmLy6D (Sm29 induces protective immunity in experimental models, human immunoglobulin responses to representative SmLy6 family members have yet to be thoroughly explored.Using a PSI-BLAST-based search, we present a comprehensive reanalysis of the Schistosoma mansoni Ly6 family (SmLy6A-K. Our examination extends the number of members to eleven (including three novel proteins and provides strong evidence that the previously identified vaccine candidate Sm29 (renamed SmLy6D is a unique double uPAR/Ly6 domain-containing representative. Presence of canonical cysteine residues, signal peptides and GPI-anchor sites strongly suggest that all SmLy6 proteins are cell surface-bound. To provide evidence that SmLy6 members are immunogenic in human populations, we report IgG1 (as well as IgG4 and IgE responses against two surface-bound representatives (SmLy6A and SmLy6B within a cohort of S. mansoni-infected Ugandan males before and after praziquantel treatment. While pre-treatment IgG1 prevalence for SmLy6A and SmLy6B differs amongst the studied population (7.4% and 25.3% of the cohort, respectively, these values are both higher than IgG1 prevalence (2.7% for a sub-surface tegumental antigen, SmTAL1. Further, post-treatment IgG1 levels against surface-associated SmLy6A and SmLy6B significantly drop (p = 0.020 and p < 0.001, respectively when compared to rising Ig

The Diversity of Diffuse Ly α Nebulae around Star-forming Galaxies at High Redshift

Energy Technology Data Exchange (ETDEWEB)

Xue, Rui; Lee, Kyoung-Soo [Department of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Dey, Arjun; Inami, Hanae [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Reddy, Naveen [Department of Physics and Astronomy, University of California, Riverside, 900 University Avenue, Riverside, CA 92521 (United States); Hong, Sungryong [Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712 (United States); Prescott, Moire K. M. [Department of Astronomy, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88001 (United States); Jannuzi, Buell T. [Steward Observatory, University of Arizona, 933 N Cherry Avenue, Tucson, AZ 85721 (United States); Gonzalez, Anthony H. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States)

2017-03-10

We report the detection of diffuse Ly α emission, or Ly α halos (LAHs), around star-forming galaxies at z ≈ 3.78 and 2.66 in the NOAO Deep Wide-Field Survey Boötes field. Our samples consist of a total of ∼1400 galaxies, within two separate regions containing spectroscopically confirmed galaxy overdensities. They provide a unique opportunity to investigate how the LAH characteristics vary with host galaxy large-scale environment and physical properties. We stack Ly α images of different samples defined by these properties and measure their median LAH sizes by decomposing the stacked Ly α radial profile into a compact galaxy-like and an extended halo-like component. We find that the exponential scale-length of LAHs depends on UV continuum and Ly α luminosities, but not on Ly α equivalent widths or galaxy overdensity parameters. The full samples, which are dominated by low UV-continuum luminosity Ly α emitters ( M {sub UV} ≳ −21), exhibit LAH sizes of 5–6 kpc. However, the most UV- or Ly α- luminous galaxies have more extended halos with scale-lengths of 7–9 kpc. The stacked Ly α radial profiles decline more steeply than recent theoretical predictions that include the contributions from gravitational cooling of infalling gas and from low-level star formation in satellites. However, the LAH extent matches what one would expect for photons produced in the galaxy and then resonantly scattered by gas in an outflowing envelope. The observed trends of LAH sizes with host galaxy properties suggest that the physical conditions of the circumgalactic medium (covering fraction, H i column density, and outflow velocity) change with halo mass and/or star formation rates.

Deep learning of quasar spectra to discover and characterize damped Lyα systems

Science.gov (United States)

Parks, David; Prochaska, J. Xavier; Dong, Shawfeng; Cai, Zheng

2018-05-01

We have designed, developed, and applied a convolutional neural network (CNN) architecture using multi-task learning to search for and characterize strong H I Lyα absorption in quasar spectra. Without any explicit modelling of the quasar continuum or application of the predicted line profile for Lyα from quantum mechanics, our algorithm predicts the presence of strong H I absorption and estimates the corresponding redshift zabs and H I column density N_{H I}, with emphasis on damped Lyα systems (DLAs, absorbers with N_{H I}≥ 2 × 10^{20} cm^{-2}). We tuned the CNN model using a custom training set of DLAs injected into DLA-free quasar spectra from the Sloan Digital Sky Survey (SDSS), data release 5 (DR5). Testing on a held-back validation set demonstrates a high incidence of DLAs recovered by the algorithm (97.4 per cent as DLAs and 99 per cent as an H I absorber with N_{H I}> 10^{19.5} cm^{-2}) and excellent estimates for zabs and N_{H I}. Similar results are obtained against a human-generated survey of the SDSS DR5 data set. The algorithm yields a low incidence of false positives and negatives but is challenged by overlapping DLAs and/or very high N_{H I} systems. We have applied this CNN model to the quasar spectra of SDSS DR7 and the Baryon Oscillation Spectroscopic Survey (data release 12) and provide catalogues of 4913 and 50 969 DLAs, respectively (including 1659 and 9230 high-confidence DLAs that were previously unpublished). This work validates the application of deep learning techniques to astronomical spectra for both classification and quantitative measurements.

Anne-Ly Võlli: Iga inimene ja asutus vajab omamoodi lähenemist / Anne-Ly Võlli ; intervjueerinud Jaanika Kressa

Index Scriptorium Estoniae

Võlli, Anne-Ly, 1976-

2009-01-01

MTÜ Jõgevamaa Omavalitsuste Aktiviseerimiskeskus kinnitas avaliku konkursi tulemusel juhatuse liikmeks Anne-Ly Võlli, kelle ülesandeks on keskuse tegevuse juhtimine ja koostöö arendamine partneromavalitsuste ja teiste koostööpartnerite vahel

Metal enriched gaseous halos around distant radio galaxies: Clues to feedback in galaxy formation

Energy Technology Data Exchange (ETDEWEB)

Reuland, M; van Breugel, W; de Vries, W; Dopita, A; Dey, A; Miley, G; Rottgering, H; Venemans, B; Stanford, S A; Lacy, M; Spinrad, H; Dawson, S; Stern, D; Bunker, A

2006-08-01

We present the results of an optical and near-IR spectroscopic study of giant nebular emission line halos associated with three z > 3 radio galaxies, 4C 41.17, 4C 60.07 and B2 0902+34. Previous deep narrow band Ly{alpha} imaging had revealed complex morphologies with sizes up to 100 kpc, possibly connected to outflows and AGN feedback from the central regions. The outer regions of these halos show quiet kinematics with typical velocity dispersions of a few hundred km s{sup -1}, and velocity shears that can mostly be interpreted as being due to rotation. The inner regions show shocked cocoons of gas closely associated with the radio lobes. These display disturbed kinematics and have expansion velocities and/or velocity dispersions >1000 km s{sup -1}. The core region is chemically evolved, and we also find spectroscopic evidence for the ejection of enriched material in 4C 41.17 up to a distance of {approx} 60 kpc along the radio-axis. The dynamical structures traced in the Ly{alpha} line are, in most cases, closely echoed in the Carbon and Oxygen lines. This shows that the Ly{alpha} line is produced in a highly clumped medium of small filling factor, and can therefore be used as a tracer of the dynamics of HzRGs. We conclude that these HzRGs are undergoing a final jet-induced phase of star formation with ejection of most of their interstellar medium before becoming 'red and dead' Elliptical galaxies.

Comparative effects of RRR-alpha- and RRR-gamma-tocopherol on proliferation and apoptosis in human colon cancer cell lines.

Science.gov (United States)

Campbell, Sharon E; Stone, William L; Lee, Steven; Whaley, Sarah; Yang, Hongsong; Qui, Min; Goforth, Paige; Sherman, Devin; McHaffie, Derek; Krishnan, Koyamangalath

2006-01-17

Mediterranean societies, with diets rich in vitamin E isoforms, have a lower risk for colon cancer than those of northern Europe and the Americas. Vitamin E rich diets may neutralize free radicals generated by fecal bacteria in the gut and prevent DNA damage, but signal transduction activities can occur independent of the antioxidant function. The term vitamin E represents eight structurally related compounds, each differing in their potency and mechanisms of chemoprevention. The RRR-gamma-tocopherol isoform is found primarily in the US diet, while RRR-alpha-tocopherol is highest in the plasma. The effectiveness of RRR-alpha- and RRR-gamma-tocopherol at inhibiting cell growth and inducing apoptosis in colon cancer cell lines with varying molecular characteristics (SW480, HCT-15, HCT-116 and HT-29) and primary colon cells (CCD-112CoN, nontransformed normal phenotype) was studied. Colon cells were treated with and without RRR-alpha- or RRR-gamma-tocopherol using varying tocopherol concentrations and time intervals. Cell proliferation and apoptosis were measured using the trypan blue assay, annexin V staining, DNA laddering and caspase activation. Treatment with RRR-gamma-tocopherol resulted in significant cell death for all cancer cell lines tested, while RRR-alpha-tocopherol did not. Further, RRR-gamma-tocopherol treatment showed no cytotoxicity to normal colon cells CCD-112CoN at the highest concentration and time point tested. RRR-gamma-tocopherol treatment resulted in cleavage of PARP, caspase 3, 7, and 8, but not caspase 9. Differences in the percentage cell death and apoptosis were observed in different cell lines suggesting that molecular differences in these cell lines may influence the ability of RRR-gamma-tocopherol to induce cell death. This is the first study to demonstrate that multiple colon cancer cell lines containing varying genetic alterations will under go growth reduction and apoptosis in the presence of RRR-gamma-tocopherol without damage to

Cellular determinants of the inverse cross sensitivity of mouse lymphoma L5178Y cell lines to ionizing radiation and hydrogen peroxide

International Nuclear Information System (INIS)

Kruszewski, M.

1999-01-01

The pair of L5178Y sublines (LY-R and LY-S) is exceptional among mammalian cell lines because of their unique inverse cross-sensitivity to ionizing radiation and hydrogen peroxide. The high sensitivity of LY-S cells to ionizing radiation is reasonably explained by the impairment of DNA double strand breaks rejoining. Although the enzymatic defect of LY-S cells is not yet identified, the more pronounced effect of DNA-dependent protein kinase (DNA-PK) inhibitor (OK-1035) on DNA damage repair after 8 Gy x-irradiation in LY-R cells than in LY-S cells, suggests that LY-S cells may be defective in DNA-PK activity or in the other enzymatic activities downstream from DNA-PK. An additional feature is a higher protection of DNA against ionizing radiation by nuclear proteins in LY-R cells. These data support the concept that nuclear matrix organization may contribute to the cellular susceptibility to DNA damaging agents. Ionizing radiation-sensitive LY-S cells suffer also more DNA base damage than ionizing radiation-resistant LY-R cells. However, the repair rates of the γ-ray-induced DNA base damage in LY sublines are related neither to the initial amounts of the damaged bases nor to the lethal or mutagenic effects of ionizing radiation. In contrast, hydrogen peroxide (H 2 O 2 ) sensitive LY-R cells suffer more DNA base damage after H 2 O 2 treatment. This may be due to the lower activity of catalase and/or the lower level of glutathione and other monobromobimane-reactive thiols in LY-R cells than in LY-S cells. However, the main cause of LY-R cells' sensitivity to H 2 O 2 seems to be a higher iron ion content in these cells as compared to LY-S cells. A higher content of iron ions and a higher iron:copper ratio is found in isolated nuclei of LY-R cells than in those of LY-S cells. This is further confirmed by a higher ''labile iron'' pool in LY-R cells than in LY-S cells. Further evidence of different ions content in LY cells and its influence on nuclear matrix organization

Effect of polarized radiative transfer on the Hanle magnetic field determination in prominences: Analysis of hydrogen H alpha line observations at Pic-du-Midi

Science.gov (United States)

Bommier, V.; Deglinnocenti, E. L.; Leroy, J. L.; Sahal-Brechot, S.

1985-01-01

The linear polarization of the Hydrogen H alpha line of prominences has been computed, taking into account the effect of a magnetic field (Hanle effect), of the radiative transfer in the prominence, and of the depolarization due to collisions with the surrounding electrons and protons. The corresponding formalisms are developed in a forthcoming series of papers. In this paper, the main features of the computation method are summarized. The results of computation have been used for interpretation in terms of magnetic field vector measurements from H alpha polarimetric observations in prominences performed at Pic-du-Midi coronagraph-polarimeter. Simultaneous observations in one optically thin line (He I D(3)) and one optically thick line (H alpha) give an opportunity for solving the ambiguity on the field vector determination.

Korelace mezi délkou lyžařské tratě a rychlostí vrcholových slalomářů Correlation between the length of the ski track and the velocity of top slalom skiers

Directory of Open Access Journals (Sweden)

Blaž Lešnik

2007-02-01

Full Text Available Teoreticky je nejlepší co nejkratší lyžařská dráha (lyžařská trať. V praxi je to však těžko proveditelné a kromě toho je to velmi riskantní. Může se proto stát pouze součástí taktiky těch nejlepších soutěžících. Pomocí kinematické analýzy byly stanoveny rozdíly mezi volbou lyžařské dráhy u jednotlivých soutěžících, a to na základě vzorku vrcholových soutěžících ve světovém poháru v Kranjske Gore. Snažili jsme se zjistit, zda soutěžící dosahovali na takové lyžařské dráze vyšší rychlosti, tedy zda dosahovali rychlejšího pohybu mezi slalomovými brankami a tudíž v konečném důsledku i lep ších časových výsledků. V první části našeho výzkumu bylo prokázáno, že žádný ze soutěžících neměl v prvních dvou po sobě následujících obratech extrémně krátkou lyžařskou dráhu. Bylo rovněž zjištěno, že soutěžící s nejkratšími lyžařskými drahami v prvním obratu měli zpravidla nejdelší lyžařské dráhy v obratu druhém a naopak. Na základě těchto zjištění bylo možno tvrdit, že za současných podmínek je mimořádně obtížné, a snad dokonce nemožné, lyžovat tak, aby lyžařský oblouk byl v několika po sobě následujících obratech velmi krátký. Druhá část našeho výzkumu se zaměřila na zjišťování korelace mezi trajektorií lyží a rychlostí lyžování. Výpočty korelací prokázaly statisticky významnou korelaci mezi průměrnou rychlostí lyžování a průměrnou vzdáleností délky lyžařské dráhy od osy y v celém měřeném úseku. Bylo zjištěno, že měřený prostor překonávali soutěžící s kratší, tedy přímější, lyžařskou dráhou rychleji. Theoretically, the shortest possible line of skiing (ski track is the best one. But in practice it is very difficult to carry this out and besides it is very risky. It can therefore be only a part of the tactics of the best competitors. With

DEVELOPMENT OF AN ON-LINE, REAL-TIME ALPHA RADIATION MEASURING INSTRUMENT FOR LIQUID STREAMS

International Nuclear Information System (INIS)

1996-01-01

The Department of Energy (DOE) has expressed a need for an on-line, real-time instrument for assaying alpha-emitting radionuclides (uranium and the transuranics) in effluent waters leaving DOE sites to ensure compliance with regulatory limits. Due to the short range of alpha particles in water (approximately40 Tm), it is necessary now to intermittently collect samples of water and send them to a central laboratory for analysis. A lengthy and costly procedure is used to separate and measure the radionuclides from each sample. Large variations in radionuclide concentrations in the water may go undetected due to the sporadic sampling. Even when detected, the reading may not be representative of the actual stream concentration. To address these issues, Tecogen, a division of Thermo Power Corporation, a Thermo Electron company, is developing a real-time, field-deployable, alpha monitor based on a solid-state silicon wafer semiconductor (patent pending, to be assigned to the Department of Energy). The Thermo Alpha Monitor (TAM) will serve to monitor effluent water streams (Subsurface Contaminants Focus Area) and will be suitable for process control of remediation as well as decontamination and decommissioning operations, such as monitoring scrubber or rinse water radioactivity levels (Mixed Waste Focus Area and D and D Focus Area). It would be applicable for assaying other liquids, such as oil, or solids after proper preconditioning. Rapid isotopic alpha air monitoring is also possible using this technology. This instrument for direct counting of alpha-emitters in aqueous streams is presently being developed by Thermo Power under a development program funded by the DOE Environmental Management program (DOE-EM), administered by the Morgantown Energy Technology Center (METC). Under this contract, Thermo Power has demonstrated a solid-state, silicon-based semiconductor instrument, which uses a proprietary film-based collection system to quantitatively extract the

A New Window into Escaping Exoplanet Atmospheres: 10830 Å Line of Helium

Science.gov (United States)

Oklopčić, Antonija; Hirata, Christopher M.

2018-03-01

Observational evidence for escaping exoplanet atmospheres has been obtained for a few exoplanets to date. It comes from strong transit signals detected in the ultraviolet, most notably in the wings of the hydrogen Lyα (Lyα) line. However, the core of the Lyα line is often heavily affected by interstellar absorption and geocoronal emission, limiting the information about the atmosphere that can be extracted from that part of the spectrum. Transit observations in atomic lines that are (a) sensitive enough to trace the rarefied gas in the planetary wind and (b) do not suffer from significant extinction by the interstellar medium could enable more detailed observations, and thus provide better constraints on theoretical models of escaping atmospheres. The absorption line of a metastable state of helium at 10830 Å could satisfy both of these conditions for some exoplanets. We develop a simple 1D model of escaping planetary atmospheres containing hydrogen and helium. We use it to calculate the density profile of helium in the 23S metastable excited state and the expected in-transit absorption at 10830 Å for two exoplanets known to have escaping atmospheres. Our results indicate that exoplanets similar to GJ 436b and HD 209458b should exhibit enhanced transit depths at 10830 Å, with ∼8% and ∼2% excess absorption in the line core, respectively.

Measurements of VUV lines on dense Z-pinch plasma

International Nuclear Information System (INIS)

Bertschinger, G.

1980-01-01

The transition n = 1 to n = 2 has the most simple structure of all hydrogen transitions and the corresponding spectralline Ly-α is therefore very appropriate to reveal discrepancies between theory and experiment. In this work mainly the Ly-α spectral line of neutral hydrogen has been studied. The electron density of the Z-pinch amounts to 1.5 x 10 24 m -3 with an electron temperature of about 1.2 x 10 5 K. In this parameter range the plasma can still be studied with spectroscopic methods in the visible spectral region. Based on a space and time resolved measurement of the continuous emission spectra the plasma parameters can be determined independent of line broadening. (orig./HT) [de

Escapist Motives for On-line Gaming and Strengthening of Weak Ties

DEFF Research Database (Denmark)

Sudzina, Frantisek; Razmerita, Liana

on-line gaming. The research investigates Facebook and other on-line games separate-ly. A surprising result is that while most of the investigated escapist motives are positively correlated with strengthening of weak ties, the mundane breaking motive is negatively correlated with strengthening...

Specific Depletion of Ly6Chi Inflammatory Monocytes Prevents Immunopathology in Experimental Cerebral Malaria

Science.gov (United States)

Kuepper, Janina M.; Biswas, Aindrila; Djie-Maletz, Andrea; Limmer, Andreas; van Rooijen, Nico; Mack, Matthias; Hoerauf, Achim; Dunay, Ildiko Rita

2015-01-01

Plasmodium berghei ANKA (PbA) infection of C57BL/6 mice leads to experimental cerebral malaria (ECM) that is commonly associated with serious T cell mediated damage. In other parasitic infection models, inflammatory monocytes have been shown to regulate Th1 responses but their role in ECM remains poorly defined, whereas neutrophils are reported to contribute to ECM immune pathology. Making use of the recent development of specific monoclonal antibodies (mAb), we depleted in vivo Ly6Chi inflammatory monocytes (by anti-CCR2), Ly6G+ neutrophils (by anti-Ly6G) or both cell types (by anti-Gr1) during infection with Ovalbumin-transgenic PbA parasites (PbTg). Notably, the application of anti-Gr1 or anti-CCR2 but not anti-Ly6G antibodies into PbTg-infected mice prevented ECM development. In addition, depletion of Ly6Chi inflammatory monocytes but not neutrophils led to decreased IFNγ levels and IFNγ+CD8+ T effector cells in the brain. Importantly, anti-CCR2 mAb injection did not prevent the generation of PbTg-specific T cell responses in the periphery, whereas anti-Gr1 mAb injection strongly diminished T cell frequencies and CTL responses. In conclusion, the specific depletion of Ly6Chi inflammatory monocytes attenuated brain inflammation and immune cell recruitment to the CNS, which prevented ECM following Plasmodium infection, pointing out a substantial role of Ly6C+ monocytes in ECM inflammatory processes. PMID:25884830

[Expression and distribution of xenoantigen alpha-Gal in intervertebral disk of Chinese banna minipig inbred line].

Science.gov (United States)

Shou, Jian-guo; Mi, Jian-hong; Ying, Da-jun

2002-09-01

To investigate the expression and distribution of xenoantigen in intervertebral disk of Chinese banna minipig inbred line, and to study the availability of xenograft transplantation of intervertebral disk. Samples of intervertebral disk were collected from six Banna pigs of 8 to 11-month-old. The fixation, embedment and slice were performed. alpha-Gal specific binding lection (BSI-B4) were used as affinity reagents and affinity-immunohistochemistry assays (SABC methods and DAB stain) were conducted to detect the expression and distribution of xenoantigen (alpha-Gal). alpha-Gal was found in chondrocyte cell and chondrocyte-like cell in intervertebral disk which have the positive yellow-stained particulate aggradation. There was no stain in the matrix, elastic fiber and collagen fiber. The distribution of xenoantigen is locally in the tissue of intervertebral disk and its expression is weak. This suggests that the intervertebral disk of Banna pig may be alternative donor for xenotransplantation.

DEVELOPMENT OF AN ON-LINE, REAL-TIME ALPHA RADIATION MEASURING INSTRUMENT FOR LIQUID STREAMS

International Nuclear Information System (INIS)

Unknown

1999-01-01

The US Department of Energy (DOE) has expressed a need for an on-line, real-time instrument for assaying alpha-emitting radionuclides (uranium and the transuranics) in effluent waters leaving DOE sites to ensure compliance with regulatory limits. Due to the short range of alpha particles in water (approximately40 Im), it is necessary now to intermittently collect samples of water and send them to a central laboratory for analysis. A lengthy and costly procedure is used to separate and measure the radionuclides from each sample. Large variations in radionuclide concentrations in the water may go undetected due to the sporadic sampling. Even when detected, the reading may not be representative of the actual stream concentration. To address these issues, the Advanced Technologies Group of Thermo Power Corporation (a Thermo Electron company) is developing a real-time, field-deployable alpha monitor based on a solid-state silicon wafer semiconductor (US Patent 5,652,013 and pending, assigned to the US Department of Energy). The Thermo Water Alpha Monitor will serve to monitor effluent water streams (Subsurface Contaminants Focus Area) and will be suitable for process control of remediation as well as decontamination and decommissioning (D and D) operations, such as monitoring scrubber or rinse water radioactivity levels (Mixed Waste, Plutonium, and D and D Focus Area). It would be applicable for assaying other liquids, such as oil, or solids after proper preconditioning. Rapid isotopic alpha air monitoring is also possible using this technology. This report details the program's accomplishments to date. Most significantly, the Alpha Monitoring Instrument was successfully field demonstrated on water 100X below the Environmental Protection Agency's proposed safe drinking water limit--down to under 1 pCi/1. During the Field Test, the Alpha Monitoring Instrument successfully analyzed isotopic uranium levels on a total of five different surface water, process water, and

A SUCCESSFUL BROADBAND SURVEY FOR GIANT Lyα NEBULAE. I. SURVEY DESIGN AND CANDIDATE SELECTION

International Nuclear Information System (INIS)

Prescott, Moire K. M.; Dey, Arjun; Jannuzi, Buell T.

2012-01-01

Giant Lyα nebulae (or Lyα 'blobs') are likely sites of ongoing massive galaxy formation, but the rarity of these powerful sources has made it difficult to form a coherent picture of their properties, ionization mechanisms, and space density. Systematic narrowband Lyα nebula surveys are ongoing, but the small redshift range covered and the observational expense limit the comoving volume that can be probed by even the largest of these surveys and pose a significant problem when searching for such rare sources. We have developed a systematic search technique designed to find large Lyα nebulae at 2 ∼ 2 NOAO Deep Wide-Field Survey Boötes field. With a total survey comoving volume of ≈10 8 h –3 70 Mpc 3 , this is the largest volume survey for Lyα nebulae ever undertaken. In this first paper in the series, we present the details of the survey design and a systematically selected sample of 79 candidates, which includes one previously discovered Lyα nebula.

First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z ∼ 7

Energy Technology Data Exchange (ETDEWEB)

Zheng, Zhen-Ya; Jiang, Chunyan [CAS Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Shanghai 200030 (China); Wang, Junxian; Hu, Weida; Kong, Xu [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China); Rhoads, James; Malhotra, Sangeeta; Gonzalez, Alicia [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Infante, Leopoldo; Galaz, Gaspar; Barrientos, L. Felipe [Institute of Astrophysics and Center for Astroengineering, Pontificia Universidad Catolica de Chile, Santiago 7820436 (Chile); Walker, Alistair R. [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile); Jiang, Linhua [The Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Hibon, Pascale [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago (Chile); Zheng, XianZhong, E-mail: zhengzy@shao.ac.cn, E-mail: linfante@astro.puc.cl, E-mail: jxw@ustc.edu.cn, E-mail: Sangeeta.Malhotra@asu.edu, E-mail: James.Rhoads@asu.edu [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

2017-06-20

We present the first results from the ongoing Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) project, which is the largest narrowband survey for z ∼ 7 galaxies to date. Using a specially built narrowband filter NB964 for the superb large-area Dark Energy Camera (DECam) on the NOAO/CTIO 4 m Blanco telescope, LAGER has collected 34 hr NB964 narrowband imaging data in the 3 deg{sup 2} COSMOS field. We have identified 23 Ly α Emitter candidates at z = 6.9 in the central 2-deg{sup 2} region, where DECam and public COSMOS multi-band images exist. The resulting luminosity function (LF) can be described as a Schechter function modified by a significant excess at the bright end (four galaxies with L {sub Lyα∼} 10{sup 43.4±0.2} erg s{sup −1}). The number density at L {sub Ly} {sub α} ∼ 10{sup 43.4±0.2} erg s{sup −1} is little changed from z = 6.6, while at fainter L {sub Lyα} it is substantially reduced. Overall, we see a fourfold reduction in Ly α luminosity density from z = 5.7 to z = 6.9. Combined with a more modest evolution of the continuum UV luminosity density, this suggests a factor of ∼3 suppression of Ly α by radiative transfer through the z ∼ 7 intergalactic medium (IGM). It indicates an IGM neutral fraction of x {sub Hi} ∼ 0.4–0.6 (assuming Ly α velocity offsets of 100–200 km s{sup −1}). The changing shape of the Ly α LF between z ≲ 6.6 and z = 6.9 supports the hypothesis of ionized bubbles in a patchy reionization at z ∼ 7.

Myostatin antibody (LY2495655) in older weak fallers: a proof-of-concept, randomised, phase 2 trial

Science.gov (United States)

BACKGROUND: Myostatin inhibits skeletal muscle growth. The humanised monoclonal antibody LY2495655 (LY) binds and neutralises myostatin. We aimed to test whether LY increases appendicular lean body mass (aLBM) and improves physical performance in older individuals who have had recent falls and low m...

The intrinsic far-UV spectrum of the high-redshift quasar B1422+231

Science.gov (United States)

O'Dowd, M.; Bate, N. F.; Webster, R. L.; Labrie, K.; King, A. L.; Yong, S.-. Y.

2018-02-01

We present new spectroscopy of the z = 3.62 gravitationally lensed quasar B1422+117 from the Gemini North GMOS integral field spectrograph. We observe significant differential magnifications between the broad emission lines and the continuum, as well as across the velocity structure of the Lyman-α line. We take advantage of this differential microlensing to algebraically decompose the quasar spectrum into the absorbed broad emission line and absorbed continuum components. We use the latter to derive the intrinsic Ly α forest absorption spectrum. The proximity effect is clearly detected, with a proximity zone edge of 8.6-17.3 Mpc from the quasar, implying (perhaps intermittent) activity over at least 28 Myr. The Ly α line profile exhibits a blue excess that is inconsistent with a symmetric fit to the unabsorbed red side. This has important implications for the use of this fitting technique in estimating the absorbed blue Ly α wings of Gunn-Peterson trough quasars.

The z=0.0912 and z=0.2212 damped Ly alpha galaxies along the sight line toward the quasar OI 363

NARCIS (Netherlands)

Turnshek, DA; Rao, S; Nestor, D; Lane, W; Monier, E; Bergeron, J; Smette, A

2001-01-01

New optical and infrared observations along the sight line toward the quasar OI 363 (0738+313) are presented and discussed. Excluding quasars selectively observed because they were known to be located behind gas-rich galaxies and systems which lack confirming UV spectroscopic observations of the

Positive regulation of plasmacytoid dendritic cell function via Ly49Q recognition of class I MHC

Science.gov (United States)

Tai, Lee-Hwa; Goulet, Marie-Line; Belanger, Simon; Toyama-Sorimachi, Noriko; Fodil-Cornu, Nassima; Vidal, Silvia M.; Troke, Angela D.; McVicar, Daniel W.; Makrigiannis, Andrew P.

2008-01-01

Plasmacytoid dendritic cells (pDCs) are an important source of type I interferon (IFN) during initial immune responses to viral infections. In mice, pDCs are uniquely characterized by high-level expression of Ly49Q, a C-type lectin-like receptor specific for class I major histocompatibility complex (MHC) molecules. Despite having a cytoplasmic immunoreceptor tyrosine-based inhibitory motif, Ly49Q was found to enhance pDC function in vitro, as pDC cytokine production in response to the Toll-like receptor (TLR) 9 agonist CpG-oligonucleotide (ODN) could be blocked using soluble monoclonal antibody (mAb) to Ly49Q or H-2Kb. Conversely, CpG-ODN–dependent IFN-α production by pDCs was greatly augmented upon receptor cross-linking using immobilized anti-Ly49Q mAb or recombinant H-2Kb ligand. Accordingly, Ly49Q-deficient pDCs displayed a severely reduced capacity to produce cytokines in response to TLR7 and TLR9 stimulation both in vitro and in vivo. Finally, TLR9-dependent antiviral responses were compromised in Ly49Q-null mice infected with mouse cytomegalovirus. Thus, class I MHC recognition by Ly49Q on pDCs is necessary for optimal activation of innate immune responses in vivo. PMID:19075287

The Properties of the local Interstellar Medium and the Interaction of the Stellar Winds of epsilon Indi and lambda Andromedae with the Interstellar Environment

Science.gov (United States)

Wood, Brian E.; Alexander, William R.; Linsky, Jeffrey L.

1996-01-01

We present new observations of the Ly alpha lines of Epsilon Indi (K5 5) and A Andromedae (G8 4-3 + ?) These data were obtained by the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope. Analysis of the interstellar H 1 and D 1 absorption lines reveals that the velocities and temperatures inferred from the H 1 lines are inconsistent with the parameters inferred from the D 1 lines, unless the H 1 absorption is assumed to be produced by two absorption components. One absorption component is produced by interstellar material. For both lines of sight observed, the velocity of this component is consistent with the velocity predicted by the local flow vector. For the Epsilon Indi data, the large velocity separation between the stellar emission and the interstellar absorption allows us to measure the H 1 column density independent of the shape of the intrinsic stellar Ly alpha profile. This approach permits us to quote an accurate column density and to assess its uncertainty with far more confidence than in previous analyses, for which the errors were dominated by uncertainties in the assumed stellar profiles.

Specific depletion of Ly6C(hi) inflammatory monocytes prevents immunopathology in experimental cerebral malaria.

Science.gov (United States)

Schumak, Beatrix; Klocke, Katrin; Kuepper, Janina M; Biswas, Aindrila; Djie-Maletz, Andrea; Limmer, Andreas; van Rooijen, Nico; Mack, Matthias; Hoerauf, Achim; Dunay, Ildiko Rita

2015-01-01

Plasmodium berghei ANKA (PbA) infection of C57BL/6 mice leads to experimental cerebral malaria (ECM) that is commonly associated with serious T cell mediated damage. In other parasitic infection models, inflammatory monocytes have been shown to regulate Th1 responses but their role in ECM remains poorly defined, whereas neutrophils are reported to contribute to ECM immune pathology. Making use of the recent development of specific monoclonal antibodies (mAb), we depleted in vivo Ly6C(hi) inflammatory monocytes (by anti-CCR2), Ly6G+ neutrophils (by anti-Ly6G) or both cell types (by anti-Gr1) during infection with Ovalbumin-transgenic PbA parasites (PbTg). Notably, the application of anti-Gr1 or anti-CCR2 but not anti-Ly6G antibodies into PbTg-infected mice prevented ECM development. In addition, depletion of Ly6C(hi) inflammatory monocytes but not neutrophils led to decreased IFNγ levels and IFNγ+CD8+ T effector cells in the brain. Importantly, anti-CCR2 mAb injection did not prevent the generation of PbTg-specific T cell responses in the periphery, whereas anti-Gr1 mAb injection strongly diminished T cell frequencies and CTL responses. In conclusion, the specific depletion of Ly6C(hi) inflammatory monocytes attenuated brain inflammation and immune cell recruitment to the CNS, which prevented ECM following Plasmodium infection, pointing out a substantial role of Ly6C+ monocytes in ECM inflammatory processes.

Extensive Sampling of Forest Carbon using High Density Power Line Lidar

Science.gov (United States)

Hampton, H. M.; Chen, Q.; Dye, D. G.; Hungate, B. A.

2013-12-01

unmanaged areas, using high point density lidar collected over transmission line corridors. The lidar metric of quadratic mean height guided our selection of field plots spanning the full range from low to high levels of aboveground biomass across the study region. Before model selection, we minimized two of the major sources of errors in lidar calibration: variance in tree allometry across landscapes and plot edge effects (spatial mismatch between field measurements and lidar points). We tested an assortment of model selection techniques and goodness of fit measures for deriving forest structural metrics of interest. For example, we obtained an R-squared value for aboveground biomass (Mg/ha) of 0.9 using stepwise regression. The forest metrics obtained are being used in the next stage of the project to parameterize biogeochemical models linking terrestrial carbon pools and atmospheric greenhouse gas exchanges.

WARM GAS IN THE VIRGO CLUSTER. I. DISTRIBUTION OF Lyα ABSORBERS

International Nuclear Information System (INIS)

Yoon, Joo Heon; Putman, Mary E.; Bryan, Greg L.; Thom, Christopher; Chen, Hsiao-Wen

2012-01-01

The first systematic study of the warm gas (T = 10 4–5 K) distribution across a galaxy cluster is presented using multiple background QSOs in and around the Virgo Cluster. We detect 25 Lyα absorbers (N HI = 10 13.1–15.4 cm –2 ) in the Virgo velocity range toward 9 of 12 QSO sightlines observed with the Cosmic Origin Spectrograph, with a cluster impact parameter range of 0.36-1.65 Mpc (0.23-1.05 R vir ). Including 18 Lyα absorbers previously detected by STIS or GHRS toward 7 of 11 background QSOs in and around the Virgo Cluster, we establish a sample of 43 absorbers toward a total of 23 background probes for studying the incidence of Lyα absorbers in and around the Virgo Cluster. With these absorbers, we find (1) warm gas is predominantly in the outskirts of the cluster and avoids the X-ray-detected hot intracluster medium (ICM). Also, Lyα absorption strength increases with cluster impact parameter. (2) Lyα-absorbing warm gas traces cold H I-emitting gas in the substructures of the Virgo Cluster. (3) Including the absorbers associated with the surrounding substructures, the warm gas covering fraction (100% for N HI > 10 13.1 cm –2 ) is in agreement with cosmological simulations. We speculate that the observed warm gas is part of large-scale gas flows feeding the cluster both in the ICM and galaxies.

Materiály pro superkondenzátory

OpenAIRE

Dvořák, Petr

2014-01-01

Tato dizertační práce se zabývá elektrodovými materiály, kapalnými a gelovými elektrolyty vhodnými pro superkondenzátory. V oblasti elektrodových materiálů byly zkoumány uhlíkové materiály na bázi uhlíkových sazí, expandovaného a mikromletého grafitu vhodné pro superkondenzátory pracující na principu dvojvrstvy. Další oblastí, které se tato práce věnuje, jsou kapalné aprotické elektrolyty připravené z vhodných typů solí a bezvodných organických rozpouštědel. Poslední část této práce je zaměře...

Nonclassical Ly6C− Monocytes Drive the Development of Inflammatory Arthritis in Mice

Directory of Open Access Journals (Sweden)

Alexander V. Misharin

2014-10-01

Full Text Available Different subsets and/or polarized phenotypes of monocytes and macrophages may play distinct roles during the development and resolution of inflammation. Here, we demonstrate in a murine model of rheumatoid arthritis that nonclassical Ly6C− monocytes are required for the initiation and progression of sterile joint inflammation. Moreover, nonclassical Ly6C− monocytes differentiate into inflammatory macrophages (M1, which drive disease pathogenesis and display plasticity during the resolution phase. During the development of arthritis, these cells polarize toward an alternatively activated phenotype (M2, promoting the resolution of joint inflammation. The influx of Ly6C− monocytes and their subsequent classical and then alternative activation occurs without changes in synovial tissue-resident macrophages, which express markers of M2 polarization throughout the course of the arthritis and attenuate joint inflammation during the initiation phase. These data suggest that circulating Ly6C− monocytes recruited to the joint upon injury orchestrate the development and resolution of autoimmune joint inflammation.

Diagnostics of red-shifted H-alpha line emission from a C-class flare with full non-LTE radiative and hydrodynamic approach

Science.gov (United States)

Druett, M. K.; Zharkova, V. V.; Scullion, E.; Zharkov, S.; Matthews, S. A.

2016-12-01

We analyse H-alpha line profiles with strong redshifts during the C1.8 flare on 1st July 2012 obtained from the Swedish Solar Telescope (SST) closely resembling the previous observations (Wuelser and Marti, 1989). The flare has a magnetic field configuration with two levels of loop structures. The kernels with red shifts are observed in one of the H-alpha ribbons in the south-west location formed after the main impulse recorded in the north-east. The locations of H-alpha kernels with red shifts reveal close temporal and spatial correlation with weaker HXR signatures and coincide with the locations of coronal jets observed with AIA/SDO. For interpretation we apply a revised 1D hydrodynamic and non-LTE (NLTE) radiative model for 5 level plus continuum model hydrogen atom (Druett & Zharkova, 2016) considering radiative, thermal and non-thermal excitation and ionisation by beam electrons with the updated beam densities (Zharkova & Dobranskis, 2016) and analytical excitation/ionisation rates (Zharkova& Kobylinskijj, 1993). We find the simultaneous solutions of steady state and radiative transfer equations in all optically-thick lines and continua. The electron and ion temperatures, ambient density and macrovelocity of the ambient plasma are derived from a 1D hydrodynamic model with initial condition of the pre-flaring photosphere for the two fluid ambient plasma heated by beam electrons (Zharkova & Zharkov, 2007). We simulate distributions over precipitation depth of ionisation and departure coefficients for all the hydrogen atom transitions including the deviation of ionisation from Saha equation affected by non-thermal electron beams. We show that in the very first seconds after the beam onset Balmer line profiles are sensitive to the effect of beam electrons. The combination of the additional ionisation caused by beam electrons leading to a very strong Stark effect in Balmer lines with the hydrodynamic heating and formation of a low temperature shock in the

Predicting alpha diversity of African rain forests: models based on climate and satellite-derived data do not perform better than a purely spatial model

NARCIS (Netherlands)

Parmentier, I.; Harrigan, R.; Buermann, W.; Mitchard, E.T.A.; Saatchi, S.; Malhi, Y.; Bongers, F.; Hawthorne, W.D.; Leal, M.E.; Lewis, S.; Nusbaumer, L.; Sheil, D.; Sosef, M.S.M.; Bakayoko, A.; Chuyong, G.; Chatelain, C.; Comiskey, J.; Dauby, G.; Doucet, J.L.; Hardy, O.

2011-01-01

Aim Our aim was to evaluate the extent to which we can predict and map tree alpha diversity across broad spatial scales either by using climate and remote sensing data or by exploiting spatial autocorrelation patterns. Location Tropical rain forest, West Africa and Atlantic Central Africa. Methods

Discovery of a z = 7.452 High Equivalent Width Lyα Emitter from the Hubble Space Telescope  Faint Infrared Grism Survey

Science.gov (United States)

Larson, Rebecca L.; Finkelstein, Steven L.; Pirzkal, Norbert; Ryan, Russell; Tilvi, Vithal; Malhotra, Sangeeta; Rhoads, James; Finkelstein, Keely; Jung, Intae; Christensen, Lise; Cimatti, Andrea; Ferreras, Ignacio; Grogin, Norman; Koekemoer, Anton M.; Hathi, Nimish; O’Connell, Robert; Östlin, Göran; Pasquali, Anna; Pharo, John; Rothberg, Barry; Windhorst, Rogier A.; The FIGS Team

2018-05-01

We present the results of an unbiased search for Lyα emission from continuum-selected 5.6 data set consists of 160 orbits of G102 slitless grism spectroscopy obtained with the Hubble Space Telescope(HST)/WFC3 as part of the Faint Infrared Grism Survey (FIGS; PI: Malhotra), which obtains deep slitless spectra of all sources in four fields, and was designed to minimize contamination in observations of previously identified high-redshift galaxy candidates. The FIGS data can potentially spectroscopically confirm the redshifts of galaxies, and as Lyα emission is resonantly scattered by neutral gas, FIGS can also constrain the ionization state of the intergalactic medium during the epoch of reionization. These data have sufficient depth to detect Lyα emission in this epoch, as Tilvi et al. have published the FIGS detection of previously known Lyα emission at z = 7.51. The FIGS data use five separate roll angles of HST to mitigate the contamination by nearby galaxies. We created a method that accounts for and removes the contamination from surrounding galaxies and also removes any dispersed continuum light from each individual spectrum. We searched for significant (>4σ) emission lines using two different automated detection methods, free of any visual inspection biases. Applying these methods on photometrically selected high-redshift candidates between 5.6 7 (140.3 ± 19.0 Å).

Lyα-Lyman continuum connection in 3.5 ≤ z ≤ 4.3 star-forming galaxies from the VUDS survey

Science.gov (United States)

Marchi, F.; Pentericci, L.; Guaita, L.; Schaerer, D.; Verhamme, A.; Castellano, M.; Ribeiro, B.; Garilli, B.; Fèvre, O. Le; Amorin, R.; Bardelli, S.; Cassata, P.; Durkalec, A.; Grazian, A.; Hathi, N. P.; Lemaux, B. C.; Maccagni, D.; Vanzella, E.; Zucca, E.

2018-06-01

Context. To identify the galaxies responsible for the reionization of the Universe, we must rely on the investigation of the Lyman continuum (LyC) properties of z ≲ 5 star-forming galaxies, where we can still directly observe their ionizing radiation. Aims: The aim of this work is to explore the correlation between the LyC emission and some of the proposed indirect indicators of LyC radiation at z 4 such as a bright Lyα emission and a compact UV continuum size. Methods: We selected a sample of 201 star-forming galaxies from the Vimos Ultra Deep Survey (VUDS) at 3.5 ≤ z ≤ 4.3 in the COSMOS, ECDFS, and VVDS-2h fields, including only those with reliable spectroscopic redshifts, a clean spectrum in the LyC range and clearly not contaminated by bright nearby sources in the same slit. For all galaxies we measured the Lyα EW, the Lyα velocity shift with respect to the systemic redshift, the Lyα spatial extension and the UV continuum effective radius. We then selected different sub-samples according to the properties predicted to be good LyC emission indicators: in particular we created sub-samples of galaxies with EW(Lyα) ≥ 70 Å, Lyαext ≤ 5.7 kpc, rUV ≤ 0.30 kpc and |ΔvLyα|≤ 200 km s-1. We stacked all the galaxies in each sub-sample and measured the flux density ratio (fλ(895)/fλ(1470)), that we considered to be a proxy for LyC emission. We then compared these ratios to those obtained for the complementary samples. Finally, to estimate the statistical contamination from lower redshift inter-lopers in our samples, we performed dedicated Monte Carlo simulations using an ultradeep U-band image of the ECDFS field. Results: We find that the stacks of galaxies which are UV compact (rUV ≤ 0.30 kpc) and have bright Lyα emission (EW(Lyα) ≥ 70 Å), have much higher LyC fluxes compared to the rest of the galaxy population. These parameters appear to be good indicators of LyC radiation in agreement with theoretical studies and previous observational

Co-ordinate transcriptional regulation of dopamine synthesis genes by alpha-synuclein in human neuroblastoma cell lines.

Science.gov (United States)

Baptista, Melisa J; O'Farrell, Casey; Daya, Sneha; Ahmad, Rili; Miller, David W; Hardy, John; Farrer, Matthew J; Cookson, Mark R

2003-05-01

Abnormal accumulation of alpha-synuclein in Lewy bodies is a neuropathological hallmark of both sporadic and familial Parkinson's disease (PD). Although mutations in alpha-synuclein have been identified in autosomal dominant PD, the mechanism by which dopaminergic cell death occurs remains unknown. We investigated transcriptional changes in neuroblastoma cell lines transfected with either normal or mutant (A30P or A53T) alpha-synuclein using microarrays, with confirmation of selected genes by quantitative RT-PCR. Gene products whose expression was found to be significantly altered included members of diverse functional groups such as stress response, transcription regulators, apoptosis-inducing molecules, transcription factors and membrane-bound proteins. We also found evidence of altered expression of dihydropteridine reductase, which indirectly regulates the synthesis of dopamine. Because of the importance of dopamine in PD, we investigated the expression of all the known genes in dopamine synthesis. We found co-ordinated downregulation of mRNA for GTP cyclohydrolase, sepiapterin reductase (SR), tyrosine hydroxylase (TH) and aromatic acid decarboxylase by wild-type but not mutant alpha-synuclein. These were confirmed at the protein level for SR and TH. Reduced expression of the orphan nuclear receptor Nurr1 was also noted, suggesting that the co-ordinate regulation of dopamine synthesis is regulated through this transcription factor.

The Ly49E receptor inhibits the immune control of acute Trypanosoma cruzi infection

Directory of Open Access Journals (Sweden)

Jessica Filtjens

2016-11-01

Full Text Available The protozoan parasite Trypanosoma cruzi (T. cruzi circulates in the blood upon infection and invades a variety of cells. Parasites intensively multiply during the acute phase of infection and persist lifelong at low levels in tissues and blood during the chronic phase. Natural killer (NK and NKT cells play an important role in the immune control of T. cruzi infection, mainly by releasing the cytokine IFN-γ that activates the microbicidal action of macrophages and other cells and shapes a protective type 1 immune response. The mechanisms by which immune cells are regulated to produce IFN-γ during T. cruzi infection are still incompletely understood. Here, we show that urokinase plasminogen activator (uPA is induced early upon T. cruzi infection, and remains elevated until day 20 post inoculation. We previously demonstrated that the inhibitory receptor Ly49E, which is expressed, among others, on NK and NKT cells, is triggered by uPA. Therefore, we compared wild type (WT to Ly49E knockout (KO mice for their control of experimental T. cruzi infection. Our results show that young, i.e. 4- and 6-week-old, Ly49E KO mice control the infection better than WT mice, indicated by a lower parasite load and less cachexia. The beneficial effect of Ly49E depletion is more obvious in 4-week-old male than in female mice and weakens in 8-week-old mice. In young mice, the lower T. cruzi parasitemia in Ly49E KO mice is paralleled by higher IFN-γ production compared to their WT controls. Our data indicate that Ly49E receptor expression inhibits the immune control of T. cruzi infection. This is the first demonstration that the inhibitory Ly49E receptor can interfere with the immune response to a pathogen in vivo.

Specific depletion of Ly6C(hi inflammatory monocytes prevents immunopathology in experimental cerebral malaria.

Directory of Open Access Journals (Sweden)

Beatrix Schumak

Full Text Available Plasmodium berghei ANKA (PbA infection of C57BL/6 mice leads to experimental cerebral malaria (ECM that is commonly associated with serious T cell mediated damage. In other parasitic infection models, inflammatory monocytes have been shown to regulate Th1 responses but their role in ECM remains poorly defined, whereas neutrophils are reported to contribute to ECM immune pathology. Making use of the recent development of specific monoclonal antibodies (mAb, we depleted in vivo Ly6C(hi inflammatory monocytes (by anti-CCR2, Ly6G+ neutrophils (by anti-Ly6G or both cell types (by anti-Gr1 during infection with Ovalbumin-transgenic PbA parasites (PbTg. Notably, the application of anti-Gr1 or anti-CCR2 but not anti-Ly6G antibodies into PbTg-infected mice prevented ECM development. In addition, depletion of Ly6C(hi inflammatory monocytes but not neutrophils led to decreased IFNγ levels and IFNγ+CD8+ T effector cells in the brain. Importantly, anti-CCR2 mAb injection did not prevent the generation of PbTg-specific T cell responses in the periphery, whereas anti-Gr1 mAb injection strongly diminished T cell frequencies and CTL responses. In conclusion, the specific depletion of Ly6C(hi inflammatory monocytes attenuated brain inflammation and immune cell recruitment to the CNS, which prevented ECM following Plasmodium infection, pointing out a substantial role of Ly6C+ monocytes in ECM inflammatory processes.

CHEMISTRY OF A PROTOPLANETARY DISK WITH GRAIN SETTLING AND Lyα RADIATION

International Nuclear Information System (INIS)

Fogel, Jeffrey K. J.; Bethell, Thomas J.; Bergin, Edwin A.; Calvet, Nuria; Semenov, Dmitry

2011-01-01

We present results from a model of the chemical evolution of protoplanetary disks. In our models, we directly calculate the changing propagation and penetration of a high energy radiation field with Lyα radiation included. We also explore the effect on our models of including dust grain settling. We find that, in agreement with earlier studies, the evolution of dust grains plays a large role in determining how deep the UV radiation penetrates into the disk. Significant grain settling at the midplane leads to much smaller freeze-out regions and a correspondingly larger molecular layer, which leads to an increase in column density for molecular species such as CO, CN, and SO. The inclusion of Lyα radiation impacts the disk chemistry through specific species that have large photodissociation cross sections at 1216 A. These include HCN, NH 3 , and CH 4 , for which the column densities are decreased by an order of magnitude or more due to the presence of Lyα radiation in the UV spectrum. A few species, such as CO 2 and SO, are enhanced by the presence of Lyα radiation, but rarely by more than a factor of a few.

LY294002 inhibits glucocorticoid-induced COX-2 gene expression in cardiomyocytes through a phosphatidylinositol 3 kinase-independent mechanism

International Nuclear Information System (INIS)

Sun Haipeng; Xu Beibei; Sheveleva, Elena; Chen, Qin M.

2008-01-01

Glucocorticoids induce COX-2 expression in rat cardiomyocytes. While investigating whether phosphatidylinositol 3 kinase (PI3K) plays a role in corticosterone (CT)-induced COX-2, we found that LY294002 (LY29) but not wortmannin (WM) attenuates CT from inducing COX-2 gene expression. Expression of a dominant-negative mutant of p85 subunit of PI3K failed to inhibit CT from inducing COX-2 expression. CT did not activate PI3K/AKT signaling pathway whereas LY29 and WM decreased the activity of PI3K. LY303511 (LY30), a structural analogue and a negative control for PI3K inhibitory activity of LY29, also suppressed COX-2 induction. These data suggest PI3K-independent mechanisms in regulating CT-induced COX-2 expression. LY29 and LY30 do not inhibit glucocorticoid receptor transactivity. Both compounds have been reported to inhibit Casein Kinase 2 activity and modulate potassium and calcium levels independent of PI3K, while LY29 has been reported to inhibit mammalian Target of Rapamycin (mTOR), and DNA-dependent Protein Kinase (DNA-PK). Inhibitor of Casein Kinase 2 (CK2), mTOR or DNA-PK failed to prevent CT from inducing COX-2 expression. Tetraethylammonium (TEA), a potassium channel blocker, and nimodipine, a calcium channel blocker, both attenuated CT from inducing COX-2 gene expression. CT was found to increase intracellular Ca 2+ concentration, which can be inhibited by LY29, TEA or nimodipine. These data suggest a possible role of calcium instead of PI3K in CT-induced COX-2 expression in cardiomyocytes

In vitro cytotoxicity of human recombinant tumor necrosis factor alpha in association with radiotherapy in a human ovarian carcinoma cell line

International Nuclear Information System (INIS)

Manetta, A.; Lucci, J.; Soopikian, J.; Granger, G.; Berman, M.L.; DiSaia, P.J.

1990-01-01

It has been speculated that tumor necrosis factor alpha (TNF-alpha) may decrease the cytotoxicity of radiotherapy by increasing the scavenging of toxic superoxide radicals. Because of the possible clinical implications, the cytotoxicity of TNF-alpha in combination with radiotherapy (RT) was compared with that of RT alone in a human ovarian cancer cell line. NIH:OVCAR-3 cells were incubated with TNF-alpha at 10.0, 1.0, 0.1, and 0.01 microgram/ml. Plates were divided into two groups; one received 150 cGy of radiotherapy and the other received no further therapy. Seventy-two hours later, supernatants were aspirated and viable cells were stained with a 1% solution of crystal violet. Survival of cells treated with RT plus TNF-alpha was expressed as a percentage of surviving irradiated controls. Analysis of results revealed minimal additive cell killing effect between TNF-alpha and radiotherapy at all concentrations of tumor necrosis factor, with the greatest difference noted in the group treated with 10 micrograms/ml TNF-alpha. A continued radiotherapy dose-response study with TNF-alpha showed a similar additive, not radioprotective, effect. This may have implication as a potentiator of RT in some human tumors

Interaction of LY171883 and other peroxisome proliferators with fatty-acid-binding protein isolated from rat liver.

Science.gov (United States)

Cannon, J R; Eacho, P I

1991-01-01

Fatty-acid-binding protein (FABP) is a 14 kDa protein found in hepatic cytosol which binds and transports fatty acids and other hydrophobic ligands throughout the cell. The purpose of this investigation was to determine whether LY171883, a leukotriene D4 antagonist, and other peroxisome proliferators bind to FABP and displace an endogenous fatty acid. [3H]Oleic acid was used to monitor the elution of FABP during chromatographic purification. [14C]LY171883 had a similar elution profile when substituted in the purification, indicating a common interaction with FABP. LY171883 and its structural analogue, LY189585, as well as the hypolipidaemic peroxisome proliferators clofibric acid, ciprofibrate, bezafibrate and WY14,643, displaced [3H]oleic acid binding to FABP. Analogues of LY171883 that do not induce peroxisome proliferation only weakly displaced oleate binding. [3H]Ly171883 bound directly to FABP with a Kd of 10.8 microM, compared with a Kd of 0.96 microM for [3H]oleate. LY171883 binding was inhibited by LY189585, clofibric acid, ciprofibrate and bezafibrate. These findings demonstrate that peroxisome proliferators, presumably due to their structural similarity to fatty acids, are able to bind to FABP and displace an endogenous ligand from its binding site. Interaction of peroxisome proliferators with FABP may be involved in perturbations of fatty acid metabolism caused by these agents as well as in the development of the pleiotropic response of peroxisome proliferation. Images Fig. 2. PMID:1747111

On modeling and measuring the temperature of the z ∼ 5 intergalactic medium

International Nuclear Information System (INIS)

Lidz, Adam; Malloy, Matthew

2014-01-01

The temperature of the low-density intergalactic medium (IGM) at high redshift is sensitive to the timing and nature of hydrogen and He II reionization, and can be measured from Lyman-alpha (Lyα) forest absorption spectra. Since the memory of intergalactic gas to heating during reionization gradually fades, measurements as close as possible to reionization are desirable. In addition, measuring the IGM temperature at sufficiently high redshifts should help to isolate the effects of hydrogen reionization since He II reionization starts later, at lower redshift. Motivated by this, we model the IGM temperature at z ≳ 5 using semi-numeric models of patchy reionization. We construct mock Lyα forest spectra from these models and consider their observable implications. We find that the small-scale structure in the Lyα forest is sensitive to the temperature of the IGM even at redshifts where the average absorption in the forest is as high as 90%. We forecast the accuracy at which the z ≳ 5 IGM temperature can be measured using existing samples of high resolution quasar spectra, and find that interesting constraints are possible. For example, an early reionization model in which reionization ends at z ∼ 10 should be distinguishable—at high statistical significance—from a lower redshift model where reionization completes at z ∼ 6. We discuss improvements to our modeling that may be required to robustly interpret future measurements.

Mock Quasar-Lyman-α forest data-sets for the SDSS-III Baryon Oscillation Spectroscopic Survey

Energy Technology Data Exchange (ETDEWEB)

Bautista, Julian E.; Busca, Nicolas G. [APC, Université Paris Diderot-Paris 7, CNRS/IN2P3, CEA, Observatoire de Paris, 10, rue A. Domon and L. Duquet, Paris (France); Bailey, Stephen; Font-Ribera, Andreu; Schlegel, David [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA (United States); Pieri, Matthew M. [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, 38 rue Frédéric Joliot-Curie, 13388, Marseille (France); Miralda-Escudé, Jordi; Gontcho, Satya Gontcho A. [Institut de Ciències del Cosmos, Universitat de Barcelona/IEEC, 1 Martí i Franquès, Barcelona 08028, Catalonia (Spain); Palanque-Delabrouille, Nathalie; Rich, James; Goff, Jean Marc Le [CEA, Centre de Saclay, Irfu/SPP, D128, F-91191 Gif-sur-Yvette (France); Dawson, Kyle [Department of Physics and Astronomy, University of Utah, 115 S 100 E, RM 201, Salt Lake City, UT 84112 (United States); Feng, Yu; Ho, Shirley [McWilliams Center for Cosmology, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213 (United States); Ge, Jian [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611-2055 (United States); Noterdaeme, Pasquier; Pâris, Isabelle [Université Paris 6 et CNRS, Institut d' Astrophysique de Paris, 98bis blvd. Arago, 75014 Paris (France); Rossi, Graziano, E-mail: bautista@astro.utah.edu [Department of Astronomy and Space Science, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul, 143-747 (Korea, Republic of)

2015-05-01

We describe mock data-sets generated to simulate the high-redshift quasar sample in Data Release 11 (DR11) of the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). The mock spectra contain Lyα forest correlations useful for studying the 3D correlation function including Baryon Acoustic Oscillations (BAO). They also include astrophysical effects such as quasar continuum diversity and high-density absorbers, instrumental effects such as noise and spectral resolution, as well as imperfections introduced by the SDSS pipeline treatment of the raw data. The Lyα forest BAO analysis of the BOSS collaboration, described in Delubac et al. 2014, has used these mock data-sets to develop and cross-check analysis procedures prior to performing the BAO analysis on real data, and for continued systematic cross checks. Tests presented here show that the simulations reproduce sufficiently well important characteristics of real spectra. These mock data-sets will be made available together with the data at the time of the Data Release 11.

THE ULTRAVIOLET RADIATION ENVIRONMENT AROUND M DWARF EXOPLANET HOST STARS

Energy Technology Data Exchange (ETDEWEB)

France, Kevin; Froning, Cynthia S.; Stocke, John T.; Bushinsky, Rachel [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Linsky, Jeffrey L. [JILA, University of Colorado and NIST, 440 UCB, Boulder, CO 80309 (United States); Roberge, Aki [Exoplanets and Stellar Astrophysics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Tian, Feng [Center for Earth System Sciences, Tsinghua University, Beijing 100084 (China); Desert, Jean-Michel [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Mauas, Pablo; Vieytes, Mariela [Instituto de Astronomsica del Espacio (CONICET-UBA), C.C. 67 Sucursal 28, 1428 Buenos Aires (Argentina); Walkowicz, Lucianne M., E-mail: kevin.france@colorado.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2013-02-15

The spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. Ultraviolet photons influence the atmospheric temperature profiles and production of potential biomarkers on Earth-like planets around these stars. At present, little observational or theoretical basis exists for understanding the ultraviolet spectra of M dwarfs, despite their critical importance to predicting and interpreting the spectra of potentially habitable planets as they are obtained in the coming decades. Using observations from the Hubble Space Telescope, we present a study of the UV radiation fields around nearby M dwarf planet hosts that covers both far-UV (FUV) and near-UV (NUV) wavelengths. The combined FUV+NUV spectra are publicly available in machine-readable format. We find that all six exoplanet host stars in our sample (GJ 581, GJ 876, GJ 436, GJ 832, GJ 667C, and GJ 1214) exhibit some level of chromospheric and transition region UV emission. No 'UV-quiet' M dwarfs are observed. The bright stellar Ly{alpha} emission lines are reconstructed, and we find that the Ly{alpha} line fluxes comprise {approx}37%-75% of the total 1150-3100 A flux from most M dwarfs; {approx}>10{sup 3} times the solar value. We develop an empirical scaling relation between Ly{alpha} and Mg II emission, to be used when interstellar H I attenuation precludes the direct observation of Ly{alpha}. The intrinsic unreddened flux ratio is F(Ly{alpha})/F(Mg II) = 10 {+-} 3. The F(FUV)/F(NUV) flux ratio, a driver for abiotic production of the suggested biomarkers O{sub 2} and O{sub 3}, is shown to be {approx}0.5-3 for all M dwarfs in our sample, >10{sup 3} times the solar ratio. For the four stars with moderate signal-to-noise Cosmic Origins Spectrograph time-resolved spectra, we find UV emission line variability with amplitudes of 50%-500% on 10{sup 2}-10{sup 3} s timescales. This effect should be taken into account in future UV

[Development and validation of event-specific quantitative PCR method for genetically modified maize LY038].

Science.gov (United States)

Mano, Junichi; Masubuchi, Tomoko; Hatano, Shuko; Futo, Satoshi; Koiwa, Tomohiro; Minegishi, Yasutaka; Noguchi, Akio; Kondo, Kazunari; Akiyama, Hiroshi; Teshima, Reiko; Kurashima, Takeyo; Takabatake, Reona; Kitta, Kazumi

2013-01-01

In this article, we report a novel real-time PCR-based analytical method for quantitation of the GM maize event LY038. We designed LY038-specific and maize endogenous reference DNA-specific PCR amplifications. After confirming the specificity and linearity of the LY038-specific PCR amplification, we determined the conversion factor required to calculate the weight-based content of GM organism (GMO) in a multilaboratory evaluation. Finally, in order to validate the developed method, an interlaboratory collaborative trial according to the internationally harmonized guidelines was performed with blind DNA samples containing LY038 at the mixing levels of 0, 0.5, 1.0, 5.0 and 10.0%. The precision of the method was evaluated as the RSD of reproducibility (RSDR), and the values obtained were all less than 25%. The limit of quantitation of the method was judged to be 0.5% based on the definition of ISO 24276 guideline. The results from the collaborative trial suggested that the developed quantitative method would be suitable for practical testing of LY038 maize.

CLASP2: The Chromospheric LAyer Spectro-Polarimeter

Science.gov (United States)

Rachmeler, Laurel; E McKenzie, David; Ishikawa, Ryohko; Trujillo Bueno, Javier; Auchère, Frédéric; Kobayashi, Ken; Winebarger, Amy; Bethge, Christian; Kano, Ryouhei; Kubo, Masahito; Song, Donguk; Narukage, Noriyuki; Ishikawa, Shin-nosuke; De Pontieu, Bart; Carlsson, Mats; Yoshida, Masaki; Belluzzi, Luca; Stepan, Jiri; del Pino Alemná, Tanausú; Ballester, Ernest Alsina; Asensio Ramos, Andres

2017-08-01

We present the instrument, science case, and timeline of the CLASP2 sounding rocket mission. The successful CLASP (Chromospheric Lyman-Alpha Spectro-Polarimeter) sounding rocket flight in 2015 resulted in the first-ever linear polarization measurements of solar hydrogen Lyman-alpha line, which is sensitive to the Hanle effect and can be used to constrain the magnetic field and geometric complexity of the upper chromosphere. Ly-alpha is one of several upper chromospheric lines that contain magnetic information. In the spring of 2019, we will re-fly the modified CLASP telescope to measure the full Stokes profile of Mg II h & k near 280 nm. This set of lines is sensitive to the upper chromospheric magnetic field via both the Hanle and the Zeeman effects.

Cosmic Metal Production and the Contribution of QSO Absorption Systems to the Ionizing Background

Science.gov (United States)

Madau, Piero; Shull, J. Michael

1996-01-01

The recent discovery by Cowie et al. (1995) and Tytler et al. (1995) of metals in the Ly alpha clouds shows that the intergalactic medium (IGM) at high redshift is contaminated by the products of stars and suggests that ionizing photons from massive star formation may be a significant contributor to the UV background radiation at early epochs. We assess the validity of the stellar photoionization hypothesis. Based on recent computations of metal yields and 0-star Lyman continuum (Lyc) fluxes, we find that 0.2 percent of the rest-mass energy of the metals produced is radiated as Lyc. By modeling the transfer of ionizing radiation through the IGM and the rate of chemical enrichment, we demonstrate that the background intensity of photons at 1 ryd that accompanies the production of metals in the Ly alpha forest clouds may be significant, approaching 0.5 x 10(exp -21) ergs cm squared s(-1) Hz(-1) sr(-1) at z approximately equals 3 if the Lyc escape fraction is greater than of equal to 0.25. Together with quasars, massive stars could then, in principle, provide the hydrogen and helium Lyc photons required to ionize the universe at high redshifts. We propose that observations of the He2 Gunn-Peterson effect and of the metal ionization states of the Ly alpha forest and Lyman-limit absorbers should show the signature of a stellar spectrum. We also note that the stellar photoionization model fails if a large fraction of the UV radiation emitted from stars cannot escape into the IGM, as suggested by the recent Hopkins Ultraviolet Telescope observations by Leitherer et al. (1995) of low-redshift starburst galaxies, or if most of the metals observed at z is approximately 3 were produced at much earlier epochs.

Reprocessing of Soft X-ray Emission Lines in Black Hole Accretion Disks

International Nuclear Information System (INIS)

Mauche, C W; Liedahl, D A; Mathiesen, B F; Jimenez-Garate, M A; Raymond, J C

2003-01-01

By means of a Monte Carlo code that accounts for Compton scattering and photoabsorption followed by recombination, we have investigated the radiation transfer of Lyα, Heα, and recombination continua photons of H- and He-like C, N, O, and Ne produced in the photoionized atmosphere of a relativistic black hole accretion disk. We find that photoelectric opacity causes significant attenuation of photons with energies above the O VIII K-edge; that the conversion efficiencies of these photons into lower-energy lines and recombination continua are high; and that accounting for this reprocessing significantly (by factors of 21% to 105%) increases the flux of the Lyα and Heα emission lines of H- and He-like C and O escaping the disk atmosphere

CLASP/SJ Observations of Rapid Time Variations in the Ly α Emission in a Solar Active Region

Energy Technology Data Exchange (ETDEWEB)

Ishikawa, Shin-nosuke [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252–5210 (Japan); Kubo, Masahito; Katsukawa, Yukio; Kano, Ryouhei; Narukage, Noriyuki; Ishikawa, Ryohko; Bando, Takamasa [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Winebarger, Amy; Kobayashi, Ken [NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Trujillo Bueno, Javier [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Auchère, Frédéric, E-mail: s.ishikawa@solar.isas.jaxa.jp [Institut d’Astrophysique Spatiale, CNRS/Univ. Paris-Sud 11, Bätiment 121, F-91405 Orsay (France)

2017-09-10

The Chromospheric Ly α SpectroPolarimeter (CLASP) is a sounding rocket experiment launched on 2015 September 3 to investigate the solar chromosphere and transition region. The slit-jaw (SJ) optical system captured Ly α images with a high time cadence of 0.6 s. From the CLASP/SJ observations, many variations in the solar chromosphere and transition region emission with a timescale of <1 minute were discovered. In this paper, we focus on the active region within the SJ field of view and investigate the relationship between short (<30 s) temporal variations in the Ly α emission and the coronal structures observed by Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA). We compare the Ly α temporal variations at the coronal loop footpoints observed in the AIA 211 Å (≈2 MK) and AIA 171 Å (≈0.6 MK) channels with those in the regions with bright Ly α features without a clear association with the coronal loop footpoints. We find more short (<30 s) temporal variations in the Ly α intensity in the footpoint regions. Those variations did not depend on the temperature of the coronal loops. Therefore, the temporal variations in the Ly α intensity at this timescale range could be related to the heating of the coronal structures up to temperatures around the sensitivity peak of 171 Å. No signature was found to support the scenario that these Ly α intensity variations were related to the nanoflares. Waves or jets from the lower layers (lower chromosphere or photosphere) are possible causes for this phenomenon.

MHC class I Dk locus and Ly49G2+ NK cells confer H-2k resistance to murine cytomegalovirus.

Science.gov (United States)

Xie, Xuefang; Stadnisky, Michael D; Brown, Michael G

2009-06-01

Essential NK cell-mediated murine CMV (MCMV) resistance is under histocompatibility-2(k) (H-2(k)) control in MA/My mice. We generated a panel of intra-H2(k) recombinant strains from congenic C57L.M-H2(k/b) (MCMV resistant) mice for precise genetic mapping of the critical interval. Recombination breakpoint sites were precisely mapped and MCMV resistance/susceptibility traits were determined for each of the new lines to identify the MHC locus. Strains C57L.M-H2(k)(R7) (MCMV resistant) and C57L.M-H2(k)(R2) (MCMV susceptible) are especially informative; we found that allelic variation in a 0.3-megabase interval in the class I D locus confers substantial difference in MCMV control phenotypes. When NK cell subsets responding to MCMV were examined, we found that Ly49G2(+) NK cells rapidly expand and selectively acquire an enhanced capacity for cytolytic functions only in C57L.M-H2(k)(R7). We further show that depletion of Ly49G2(+) NK cells before infection abrogated MCMV resistance in C57L.M-H2(k)(R7). We conclude that the MHC class I D locus prompts expansion and activation of Ly49G2(+) NK cells that are needed in H-2(k) MCMV resistance.

DETECTION OF A HYDROGEN CORONA IN HST Ly α IMAGES OF EUROPA IN TRANSIT OF JUPITER

Energy Technology Data Exchange (ETDEWEB)

Roth, Lorenz; Ivchenko, Nickolay; Schlatter, Nicola [KTH Royal Institute of Technology (Sweden); Retherford, Kurt D.; Becker, Tracy M.; Grava, Cesare [Southwest Research Institute, San Antonio, TX (United States); Strobel, Darrell F. [Johns Hopkins University, Baltimore, MD (United States)

2017-02-01

We report far-ultraviolet observations of Europa in transit of Jupiter obtained with the Space Telescope Imaging Spectrograph of the Hubble Space Telescope on six occasions between 2014 December and 2015 March. Absorption of Jupiter’s bright hydrogen Ly α dayglow is detected in a region several moon radii above the limb in all observations. The observed extended absorption provides the first detection of an atomic hydrogen corona around Europa. Molecular constituents in Europa’s global sputtered atmosphere are shown to be optically thin to Ly α . The observations are consistent with a radially escaping H corona with maximum densities at the surface in the range of (1.5–2.2) × 10{sup 3} cm{sup −3}, confirming the abundances predicted by Monte Carlo simulations. In addition, we search for anomalies around the limb of Europa from absorption by localized high H{sub 2}O abundances from active plumes. No significant local absorption features are detected. We find that an H{sub 2}O plume with line-of-sight column density in the order of 10{sup 16} cm{sup −2}, as inferred by Roth et al. would not be detectable based on the statistical fluctuations of the transit measurements, and hence is not excluded or further constrained. The presence of plumes with line-of-sight column densities of >2 × 10{sup 17} cm{sup −2} can be excluded at a 3- σ level during five of our six observations.

Studies on Inhibition of Proliferation of Enterovirus-71 by Compound YZ-LY-0.

Science.gov (United States)

Yang, Qingzhan; Jie, Qing; Shaw, Neil; Li, Lei; Rao, Zihe; Yin, Zheng; Lou, Zhiyong

2015-01-01

In recent years, hand-foot-and-mouth disease (HFMD), which is caused by Enteroviruses, has emerged as a serious illness. It affects mainly children under the age of five and results in high fatality rates. Enterovirus 71 (EV71) is the main causative agent of HFMD in China and currently there are no effective anti-viral drugs available to treat HFMD. In the present study, we screened compounds for inhibition of proliferation of EV71. Compound YZ-LY-0 stalled the life cycle of EV71. The inhibitor exhibited EC50 value of 0.29 μm against SK-EV006 strain of EV71. Notably, YZ-LY-0 had low cytotoxicity (CC50 > 100 μM) and a high selectivity index (over 300) in Vero and RD cells. YZ-LY-0 in combination with an EV71 RdRp inhibitor or an entry inhibitor showed an antagonistic effect at very low concentrations. However, at higher concentrations the inhibitors exhibited a synergistic effect in inhibiting viral replication. Preliminary results on investigation of the mechanism of inhibition indicate that YZ-LY-0 does not block the entry of the virus in the host cell, but instead inhibits an early stage of EV71 replication. Our studies provide a potential clinical therapeutic option against EV71 infections and suggest that a combined application of YZ-LY-0 with other inhibitors could be more effective in the treatment of HFMD.

Ly α Absorption at Transits of HD 209458b: A Comparative Study of Various Mechanisms Under Different Conditions

Energy Technology Data Exchange (ETDEWEB)

Khodachenko, M. L.; Lammer, H.; Kislyakova, K. G.; Fossati, L.; Arkhypov, O. V. [Space Research Institute, Austrian Academy of Sciences, Graz (Austria); Shaikhislamov, I. F.; Berezutsky, A. G.; Miroshnichenko, I. B.; Posukh, V. G. [Institute of Laser Physics SB RAS, Novosibirsk (Russian Federation); Johnstone, C. P., E-mail: maxim.khodachenko@oeaw.ac.at [Department of Astrophysics, University of Vienna (Austria)

2017-10-01

To shed more light on the nature of the observed Ly α absorption during transits of HD 209458b and to quantify the major mechanisms responsible for the production of fast hydrogen atoms (the so-called energetic neutral atoms, ENAs) around the planet, 2D hydrodynamic multifluid modeling of the expanding planetary upper atmosphere, which is driven by stellar XUV, and its interaction with the stellar wind has been performed. The model self-consistently describes the escaping planetary wind, taking into account the generation of ENAs due to particle acceleration by the radiation pressure and by the charge exchange between the stellar wind protons and planetary atoms. The calculations in a wide range of stellar wind parameters and XUV flux values showed that under typical Sun-like star conditions, the amount of generated ENAs is too small, and the observed absorption at the level of 6%–8% can be attributed only to the non-resonant natural line broadening. For lower XUV fluxes, e.g., during the activity minima, the number of planetary atoms that survive photoionization and give rise to ENAs increases, resulting in up to 10%–15% absorption at the blue wing of the Ly α line, caused by resonant thermal line broadening. A similar asymmetric absorption can be seen under the conditions realized during coronal mass ejections, when sufficiently high stellar wind pressure confines the escaping planetary material within a kind of bowshock around the planet. It was found that the radiation pressure in all considered cases has a negligible contribution to the production of ENAs and the corresponding absorption.

A comparison of alpha and beta diversity patterns of ferns, bryophytes and macrolichens in tropical montane forests of southern Ecuador

OpenAIRE

Mandl, N A; Lehnert, M; Kessler, M; Gradstein, S R

2010-01-01

We present a first comparison of patterns of alpha and beta diversity of ferns, mosses, liverworts and macrolichens in neotropical montane rainforests, and explore the question whether specific taxa may be used as surrogates for others. In three localities in southern Ecuador, we surveyed terrestrial and epiphytic species assemblages in ridge and slope forests in 28 plots of 400 m² each. The epiphytic habitat was significantly richer in ferns, liverworts, and macrolichens than the terrestrial...

Ectopic expression of miR-34a enhances radiosensitivity of non-small cell lung cancer cells, partly by suppressing the LyGDI signaling pathway

International Nuclear Information System (INIS)

Duan Weiming; Xu Yaxiang; Dong Yujin; Cao Lili; Tong Jian; Zhou Xinwen

2013-01-01

miR-34a is transcriptionally induced by the tumor suppressor gene p53, which is often downregulated in non-small cell lung cancer (NSCLC). To address whether the downstream signal of miR-34a is sufficient to induce apoptosis and to alter cellular radiosensitivity, a chemical synthetic miR-34a mimic was delivered into A549 and H1299 cells, with or without co-treatment of γ-irradiation. Results showed that ectopic expression of miR-34a induced dose-dependent cell growth inhibition and apoptosis in a p53-independent manner in both NSCLC cell lines. Interestingly, LyGDI was discovered as a new target gene of miR-34a, and downregulation of LyGDI promoted Rac1 activation and membrane translocation, resulting in cell apoptosis. Furthermore, restoration of miR-34a indirectly reduced cyclooxygenase-2 (COX-2) expression. Taken together, these results demonstrate that restoration of miR-34a expression enhances radiation-induced apoptosis, partly by suppressing the LyGDI signaling pathway, and miR-34a could possibly be used as a radiosensitizer for non-small cell lung cancer therapy. (author)

An ecological paradox: high species diversity and low position of the upper forest line in the Andean Depression.

Science.gov (United States)

Peters, Thorsten; Braeuning, Achim; Muenchow, Jannes; Richter, Michael

2014-06-01

Systematic investigations of the upper forest line (UFL) primarily concentrate on mid and high latitudes of the Northern Hemisphere, whereas studies of Neotropical UFLs are still fragmentary. This article outlines the extraordinary high tree diversity at the UFL within the Andean Depression and unravels the links between the comparatively low position of the local UFL, high tree-species diversity, and climate. On the basis of Gentry's rapid inventory methodology for the tropics, vegetation sampling was conducted at 12 UFL sites, and local climate (temperature, wind, precipitation, and soil moisture) was investigated at six sites. Monotypic forests dominated by Polylepis were only found at the higher located margins of the Andean Depression while the lower situated core areas were characterized by a species-rich forest, which lacked the elsewhere dominant tree-species Polylepis. In total, a remarkably high tree-species number of 255 tree species of 40 different plant families was found. Beta-diversity was also high with more than two complete species turnovers. A non-linear relationship between the floristic similarity of the investigated study sites and elevation was detected. Temperatures at the investigated study sites clearly exceeded 5.5°C, the postulated threshold value for the upper tree growth limit in the tropics. Instead, quasi-permanent trade winds, high precipitation amounts, and high soil water contents affect the local position of the UFL in a negative way. Interestingly, most of the above-mentioned factors are also contributing to the high species richness. The result is a combination of a clearly marked upper forest line depression combined with an extraordinary forest line complexity, which was an almost unknown paradox.

Damped Lyα system toward QSO1854+116: A new type of absorber?

Directory of Open Access Journals (Sweden)

Ćirković M.M.

1999-01-01

Full Text Available A puzzle of the low-redshift damped Lyα absorption system toward QSO 1854+116 is presented. Problems which conventional intepretation of damped Lyα systems encounters in this case are sketched and a possible explanation, based on transience of the phenomenon, is suggested. It is shown that the detailed Hα tomography can observationally resolve the controversy in the very near future.

Natural killer cell receptor genes in the family Equidae: not only Ly49.

Directory of Open Access Journals (Sweden)

Jan Futas

Full Text Available Natural killer (NK cells have important functions in immunity. NK recognition in mammals can be mediated through killer cell immunoglobulin-like receptors (KIR and/or killer cell lectin-like Ly49 receptors. Genes encoding highly variable NK cell receptors (NKR represent rapidly evolving genomic regions. No single conservative model of NKR genes was observed in mammals. Single-copy low polymorphic NKR genes present in one mammalian species may expand into highly polymorphic multigene families in other species. In contrast to other non-rodent mammals, multiple Ly49-like genes appear to exist in the horse, while no functional KIR genes were observed in this species. In this study, Ly49 and KIR were sought and their evolution was characterized in the entire family Equidae. Genomic sequences retrieved showed the presence of at least five highly conserved polymorphic Ly49 genes in horses, asses and zebras. These findings confirmed that the expansion of Ly49 occurred in the entire family. Several KIR-like sequences were also identified in the genome of Equids. Besides a previously identified non-functional KIR-Immunoglobulin-like transcript fusion gene (KIR-ILTA and two putative pseudogenes, a KIR3DL-like sequence was analyzed. In contrast to previous observations made in the horse, the KIR3DL sequence, genomic organization and mRNA expression suggest that all Equids might produce a functional KIR receptor protein molecule with a single non-mutated immune tyrosine-based inhibition motif (ITIM domain. No evidence for positive selection in the KIR3DL gene was found. Phylogenetic analysis including rhinoceros and tapir genomic DNA and deduced amino acid KIR-related sequences showed differences between families and even between species within the order Perissodactyla. The results suggest that the order Perissodactyla and its family Equidae with expanded Ly49 genes and with a potentially functional KIR gene may represent an interesting model for

Natural Killer Cell Receptor Genes in the Family Equidae: Not only Ly49

Science.gov (United States)

Futas, Jan; Horin, Petr

2013-01-01

Natural killer (NK) cells have important functions in immunity. NK recognition in mammals can be mediated through killer cell immunoglobulin-like receptors (KIR) and/or killer cell lectin-like Ly49 receptors. Genes encoding highly variable NK cell receptors (NKR) represent rapidly evolving genomic regions. No single conservative model of NKR genes was observed in mammals. Single-copy low polymorphic NKR genes present in one mammalian species may expand into highly polymorphic multigene families in other species. In contrast to other non-rodent mammals, multiple Ly49-like genes appear to exist in the horse, while no functional KIR genes were observed in this species. In this study, Ly49 and KIR were sought and their evolution was characterized in the entire family Equidae. Genomic sequences retrieved showed the presence of at least five highly conserved polymorphic Ly49 genes in horses, asses and zebras. These findings confirmed that the expansion of Ly49 occurred in the entire family. Several KIR-like sequences were also identified in the genome of Equids. Besides a previously identified non-functional KIR-Immunoglobulin-like transcript fusion gene (KIR-ILTA) and two putative pseudogenes, a KIR3DL-like sequence was analyzed. In contrast to previous observations made in the horse, the KIR3DL sequence, genomic organization and mRNA expression suggest that all Equids might produce a functional KIR receptor protein molecule with a single non-mutated immune tyrosine-based inhibition motif (ITIM) domain. No evidence for positive selection in the KIR3DL gene was found. Phylogenetic analysis including rhinoceros and tapir genomic DNA and deduced amino acid KIR-related sequences showed differences between families and even between species within the order Perissodactyla. The results suggest that the order Perissodactyla and its family Equidae with expanded Ly49 genes and with a potentially functional KIR gene may represent an interesting model for evolutionary biology of

A quasi-continuous observation of the {alpha}-transition of Fe{sub 1+x}S by Moessbauer line tracking

Energy Technology Data Exchange (ETDEWEB)

Mendoza Zelis, P., E-mail: pmendoza@fisica.unlp.edu.ar; Pasquevich, G. A.; Veiga, A.; Fernandez van Raap, M. B.; Sanchez, F. H. [Universidad Nacional de La Plata, CONICET, Depto. de Fisica, Fac. Ciencias Exactas, Instituto de Fisica La Plata (Argentina)

2010-01-15

Moessbauer absorption line tracking methodology, under a constant velocity strategy, is used for a quasi-continuous observation of the {alpha}-transition on slightly non stoichiometric Fe{sub 1+x}S alloy. To this end, two strategies were applied: an intelligent absorption line tracking with a control algorithm that uses the data measured in the previous region to establish the position of the next partial spectral range; and a predetermined line tracking in which temperature evolution of a partial spectral region of interest (ROI) is programmed. The latter uses results from the former, in order to achieve a quasi-continuous partial spectral observation. These experiments clearly demonstrate that line tracking allows a more efficient use of the radioactive source, as the effort is concentrated in a partial region of the spectra from which the desired information can be obtained.

Complex rearrangements within the human J delta-C delta/J alpha-C alpha locus and aberrant recombination between J alpha segments

NARCIS (Netherlands)

Baer, R.; Boehm, T.; Yssel, H.; Spits, H.; Rabbitts, T. H.

1988-01-01

We have examined DNA rearrangements within a 120 kb cloned region of the human T cell receptor J delta-C delta/J alpha-C alpha locus. Three types of pattern emerge from an analysis of T cell lines and clones. Firstly, cells with two rearrangements within J delta-C delta; secondly, cells with one

Widespread Amazon forest tree mortality from a single cross-basin squall line event

Science.gov (United States)

Negrón-Juárez, Robinson I.; Chambers, Jeffrey Q.; Guimaraes, Giuliano; Zeng, Hongcheng; Raupp, Carlos F. M.; Marra, Daniel M.; Ribeiro, Gabriel H. P. M.; Saatchi, Sassan S.; Nelson, Bruce W.; Higuchi, Niro

2010-08-01

Climate change is expected to increase the intensity of extreme precipitation events in Amazonia that in turn might produce more forest blowdowns associated with convective storms. Yet quantitative tree mortality associated with convective storms has never been reported across Amazonia, representing an important additional source of carbon to the atmosphere. Here we demonstrate that a single squall line (aligned cluster of convective storm cells) propagating across Amazonia in January, 2005, caused widespread forest tree mortality and may have contributed to the elevated mortality observed that year. Forest plot data demonstrated that the same year represented the second highest mortality rate over a 15-year annual monitoring interval. Over the Manaus region, disturbed forest patches generated by the squall followed a power-law distribution (scaling exponent α = 1.48) and produced a mortality of 0.3-0.5 million trees, equivalent to 30% of the observed annual deforestation reported in 2005 over the same area. Basin-wide, potential tree mortality from this one event was estimated at 542 ± 121 million trees, equivalent to 23% of the mean annual biomass accumulation estimated for these forests. Our results highlight the vulnerability of Amazon trees to wind-driven mortality associated with convective storms. Storm intensity is expected to increase with a warming climate, which would result in additional tree mortality and carbon release to the atmosphere, with the potential to further warm the climate system.

Stacking the Cosmic Web in fluorescent Ly α emission with MUSE

Science.gov (United States)

Gallego, Sofia G.; Cantalupo, Sebastiano; Lilly, Simon; Marino, Raffaella Anna; Pezzulli, Gabriele; Schaye, Joop; Wisotzki, Lutz; Bacon, Roland; Inami, Hanae; Akhlaghi, Mohammad; Tacchella, Sandro; Richard, Johan; Bouche, Nicolas F.; Steinmetz, Matthias; Carollo, Marcella

2018-04-01

Cosmological simulations suggest that most of the matter in the Universe is distributed along filaments connecting galaxies. Illuminated by the cosmic UV background (UVB), these structures are expected to glow in fluorescent Ly α emission with a surface brightness (SB) that is well below current limits for individual detections. Here, we perform a stacking analysis of the deepest MUSE/VLT data using three-dimensional regions (subcubes) with orientations determined by the position of neighbouring Ly α galaxies at 3 < z < 4. Our method increase the probability of detecting filamentary Ly α emission, provided that these structures are Lyman-limit systems (LLSs). By stacking 390 oriented subcubes we reach a 2σ sensitivity level of SB ≈ 0.44 × 10-20 erg s-1 cm-2 arcsec-2 in an aperture of 1 arcsec2 × 6.25 Å, three times below the expected fluorescent Ly α signal from the Haardt & Madau UVB at z ˜ 3.5. No detectable emission is found on intergalactic scales, implying that at least two thirds of our subcubes do not contain oriented LLSs. On the other hand, significant emission is detected in the circumgalactic medium (CGM) in the direction of the neighbours. The signal is stronger for galaxies with a larger number of neighbours and appears to be independent of any other galaxy properties. We estimate that preferentially oriented satellite galaxies cannot contribute significantly to this signal, suggesting instead that gas densities in the CGM are typically larger in the direction of neighbouring galaxies on cosmological scales.

Quasar-Lyman α forest cross-correlation from BOSS DR11: Baryon Acoustic Oscillations

Energy Technology Data Exchange (ETDEWEB)

Font-Ribera, Andreu [Institute of Theoretical Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich (Switzerland); Kirkby, David; Blomqvist, Michael [Department of Physics and Astronomy, University of California, 4129 Frederick Reines Hall, Irvine, CA, 92697 (United States); Busca, Nicolas; Aubourg, Éric; Bautista, Julian [APC, Université Paris Diderot-Paris 7, CNRS/IN2P3, CEA, Observatoire de Paris, 10, rue A. Domon and L. Duquet, Paris (France); Miralda-Escudé, Jordi [Institut de Ciències del Cosmos (IEEC/UB), Martí i Franquès 1, Barcelona, 08028 Catalonia (Spain); Ross, Nicholas P.; Bailey, Stephen; Beutler, Florian; Carithers, Bill [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA (United States); Slosar, Anže [Brookhaven National Laboratory, Blgd 510, Upton, NY, 11375 (United States); Rich, James; Delubac, Timothée [CEA, Centre de Saclay, IRFU, Gif-sur-Yvette, 91191 France (France); Bhardwaj, Vaishali; Bizyaev, Dmitry [Department of Astronomy, University of Washington, Box 351580, Seattle, WA, 98195 (United States); Brewington, Howard; Brinkmann, Jon [Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349-0059 (United States); Brownstein, Joel R.; Dawson, Kyle S., E-mail: font@physik.uzh.ch [Department of Physics and Astronomy, University of Utah, 115 S 1400 E, Salt Lake City, UT, 84112 (United States); and others

2014-05-01

We measure the large-scale cross-correlation of quasars with the Lyα forest absorption, using over 164,000 quasars from Data Release 11 of the SDSS-III Baryon Oscillation Spectroscopic Survey. We extend the previous study of roughly 60,000 quasars from Data Release 9 to larger separations, allowing a measurement of the Baryonic Acoustic Oscillation (BAO) scale along the line of sight c/(H(z = 2.36)r{sub s}) = 9.0±0.3 and across the line of sight D{sub A}(z = 2.36)/r{sub s} = 10.8±0.4, consistent with CMB and other BAO data. Using the best fit value of the sound horizon from Planck data (r{sub s} = 147.49 Mpc), we can translate these results to a measurement of the Hubble parameter of H(z = 2.36) = 226±8 km s{sup −1} Mpc{sup −1} and of the angular diameter distance of D{sub A}(z = 2.36) = 1590±60 Mpc. The measured cross-correlation function and an update of the code to fit the BAO scale (baofit) are made publicly available.

Tree Line Structure and Dynamics at the Northern Limit of the Larch Forest: Anabar Plateau, Siberia, Russia

Science.gov (United States)

Kharuk, Viacheslav I.; Ranson, Kenneth J.; Im, Sergey T.; Oskorbin, Pavel A.; Dvinskaya, Maria L.; Ovchinnikov, Dmitriy V.

2013-01-01

The goal of the study was to provide an analysis of climate impact before, during, and after the Little Ice Age (LIA) on the larch (Larix gmelinii) tree line at the northern extreme of Siberian forests. Recent decadal climate change impacts on the tree line, regeneration abundance, and age structure were analyzed. The location of the study area was within the forest-tundra ecotone (elevation range 170-450 m) in the Anabar Plateau, northern Siberia. Field studies were conducted along elevational transects. Tree natality/mortality and radial increment were determined based on dendrochronology analyses. Tree morphology, number of living and subfossil trees, regeneration abundance, and age structure were studied. Locations of pre-LIA, LIA, and post-LIA tree lines and refugia boundaries were established. Long-term climate variables and drought index were included in the analysis. It was found that tree mortality from the 16th century through the beginning of the 19th century caused a downward tree line recession. Sparse larch stands experienced deforestation, transforming into tundra with isolated relict trees. The maximum tree mortality and radial growth decrease were observed to have occurred at the beginning of 18th century. Now larch, at its northern boundary in Siberia, is migrating into tundra areas. Upward tree migration was induced by warming in the middle of the 19th century. Refugia played an important role in repopulation of the forest-tundra ecotone by providing a seed source and shelter for recruitment of larch regeneration. Currently this ecotone is being repopulated mainly by tree cohorts that were established after the 1930s. The last two decades of warming did not result in an acceleration of regeneration recruitment because of increased drought conditions. The regeneration line reached (but did not exceed) the pre-LIA tree line location, although contemporary tree heights and stand densities are comparatively lower than in the pre-LIA period. The mean

A MODEL FOR TYPE 2 CORONAL LINE FOREST (CLiF) AGNs

Energy Technology Data Exchange (ETDEWEB)

Glidden, Ana [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Rose, Marvin; Elvis, Martin; McDowell, Jonathan [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2016-06-10

We present a model for the classification of Coronal Line Forest Active Galactic Nuclei (CLiF AGNs). CLiF AGNs are of special interest due to their remarkably large number of emission lines, especially forbidden high-ionization lines (FHILs). Rose et al. suggest that their emission is dominated by reflection from the inner wall of the obscuring region rather than direct emission from the accretion disk. This makes CLiF AGNs laboratories to test AGN-torus models. Modeling an AGN as an accreting supermassive black hole surrounded by a cylinder of dust and gas, we show a relationship between the viewing angle and the revealed area of the inner wall. From the revealed area, we can determine the amount of FHIL emission at various angles. We calculate the strength of [Fe vii] λ 6087 emission for a number of intermediate angles (30°, 40°, and 50°) and compare the results with the luminosity of the observed emission line from six known CLiF AGNs. We find that there is good agreement between our model and the observational results. The model also enables us to determine the relationship between the type 2:type 1 AGN fraction vs the ratio of torus height to radius, h / r .

Correlation of repressed transcription of alpha-tocopherol transfer protein with serum alpha-tocopherol during hepatocarcinogenesis

NARCIS (Netherlands)

Wu, C. G.; Hoek, F. J.; Groenink, M.; Reitsma, P. H.; van Deventer, S. J.; Chamuleau, R. A.

1997-01-01

Using a subtraction-enhanced display technique, we identified a rodent alpha-tocopherol transfer protein (alpha-TTP) cDNA which exhibited markedly lower messenger RNA (mRNA) amounts in rat hepatocellular carcinoma (HCC) than in healthy controls. Several lines of evidence have substantiated that

Use of molecular markers aids in the development of diverse inbred backcross lines in Beit Alpha cucumber (Cucumis sativus L.)

Science.gov (United States)

Beit Alpha cucumber (Cucumis sativus L.) is a Mediterranean fresh-market type with a relatively narrow genetic base. To broaden its base for plant improvement, 42 diverse accessions were compared employing a previously defined standard marker array to choose wide-based parental lines for use in bac...

Colder freeze-in axinos decaying into photons

Science.gov (United States)

Bae, Kyu Jung; Kamada, Ayuki; Liew, Seng Pei; Yanagi, Keisuke

2018-03-01

We point out that 7 keV axino dark matter (DM) in the R-parity violating (RPV) supersymmetric (SUSY) Dine-Fischler-Srednicki-Zhitnitsky axion model can simultaneously reproduce the 3.5 keV x-ray line excess and evade stringent constraints from the Ly -α forest data. Peccei-Quinn symmetry breaking naturally generates both the TeV-scale μ term and the MeV-scale RPV term. The RPV term introduces a tiny axino-neutrino mixing and provides axino DM as a variant of the sterile neutrino DM explaining the 3.5 keV x-ray line excess. Axinos are produced by freeze-in processes via the μ term. The resultant phase space distribution tends to be colder than the Fermi-Dirac distribution. The inherent entropy production from late-time saxion decay makes axinos even colder than those without saxion decay. The resultant axino DM takes the correct relic density and is compatible even with the latest and strongest constraint from the Ly-α forest data.

TRANSITING THE SUN. II. THE IMPACT OF STELLAR ACTIVITY ON Lyα TRANSITS

International Nuclear Information System (INIS)

Llama, J.; Shkolnik, E. L.

2016-01-01

High-energy observations of the Sun provide an opportunity to test the limits of our ability to accurately measure the properties of transiting exoplanets in the presence of stellar activity. Here we insert the transit of a hot Jupiter into continuous disk integrated data of the Sun in Lyα from NASA’s Solar Dynamics Observatory/EVE instrument to assess the impact of stellar activity on the measured planet-to-star radius ratio (R p /R ⋆ ). In 75% of our simulated light curves, we measure the correct radius ratio; however, incorrect values can be measured if there is significant short-term variability in the light curve. The maximum measured value of R p /R ⋆ is 50% larger than the input value, which is much smaller than the large Lyα transit depths that have been reported in the literature, suggesting that for stars with activity levels comparable to the Sun, stellar activity alone cannot account for these deep transits. We ran simulations without a transit and found that stellar activity cannot mimic the Lyα transit of 55 Cancari b, strengthening the conclusion that this planet has a partially transiting exopshere. We were able to compare our simulations to more active stars by artificially increasing the variability in the Solar Lyα light curve. In the higher variability data, the largest value of R p /R ⋆ we measured is <3× the input value, which again is not large enough to reproduce the Lyα transit depth reported for the more active stars HD 189733 and GJ 436, supporting the interpretation that these planets have extended atmospheres and possible cometary tails

Alpha decay and various problems related to it

International Nuclear Information System (INIS)

Katori, Kenji

1992-01-01

On the proton-excessive nucleus side of lanthanide and actinide, alpha decay is the main decay mode. In lanthanide region, alpha decay has been measured to the drip line for most even-even nuclei. In the measurement of alpha decay, emitted energy and life are measured, but the measurement of converted alpha width remains in the limited range. In order to obtain the converted alpha width of high accuracy, the nucleus formation in larger quantity on the drip line and the simultaneous measurement with a multiple detector system including gamma ray and beta ray are required. In this paper, three topics related to alpha cluster and alpha decay and the problems that confront at present are discussed. The continuation to exist of alpha cluster structure to heavy nuclei, the analysis of lanthanide nucleus region by the alpha giant resonance model, and the new data on the alpha ray decaying from the mass of 175, 176 and 177 are reported. In lanthanide nucleus region, remarkable interference was not observed between beta-2 and beta-3 modes in the converted alpha width measured between the ground states. The present problems in alpha decay are enumerated. (K.I.)

Polarization Calibration of the Chromospheric Lyman-Alpha SpectroPolarimeter for a 0.1% Polarization Sensitivity in the VUV Range. Part II: In-Flight Calibration

Czech Academy of Sciences Publication Activity Database

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

2017-01-01

Roč. 292, č. 4 (2017), 57/1-57/19 ISSN 0038-0938 R&D Projects: GA ČR(CZ) GA16-16861S Institutional support: RVO:67985815 Keywords : solar transition region * ly-alpha * magnetohydrodynamic model Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 2.682, year: 2016

Lyman Alpha Camera for Io's SO2 atmosphere and Europa's water plumes

Science.gov (United States)

McEwen, Alfred S.; Sandel, Bill; Schneider, Nick

2014-05-01

The Student Lyman-Alpha Mapper (SLAM) was conceived for the Io Volcano Observer (IVO) mission proposal (McEwen et al., 2014) to determine the spatial and temporal variations in Io's SO2 atmosphere by recording the H Ly-α reflection over the disk (Feldman et al., 2000; Feaga et al., 2009). SO2 absorbs at H Ly-α, thereby modulating the brightness of sunlight reflected by the surface, and measures the density of the SO2 atmosphere and its variability with volcanic activity and time of day. Recently, enhancements at the Ly-α wavelength (121.57 nm) were seen near the limb of Europa and interpreted as active water plumes ~200 km high (Roth et al., 2014). We have a preliminary design for a very simple camera to image in a single bandpass at Ly-α, analogous to a simplified version of IMAGE EUV (Sandel et al. 2000). Our goal is at least 50 resolution elements across Io and/or Europa (~75 km/pixel), ~3x better than HST STIS, to be acquired at a range where the radiation noise is below 1E-4 hits/pixel/s. This goal is achieved with a Cassegrain-like telescope with a 10-cm aperture. The wavelength selection is achieved using a simple self-filtering mirror in combination with a solar-blind photocathode. A photon-counting detector based on a sealed image intensifier preserves the poisson statistics of the incoming photon flux. The intensifier window is coated with a solar-blind photocathode material (CsI). The location of each photon event is recorded by a position-sensitive anode based on crossed delay-line or wedge-and-strip technology. The sensitivity is 0.01 counts/pixel/sec/R, sufficient to estimate SO2 column abundances ranging from 1E15 to 1E17 per cm2 in a 5 min (300 sec) exposure. Sensitivity requirements to search for and image Europa plumes may be similar. Io's Ly-α brightness of ~3 kR exceeds the 0.8 kR brightness of Europa's plume reported by Roth et al. (2014), but the plume brightness is a direct measurement rather than inferring column abundance from

A potential germ cell-specific marker in Japanese flounder, Paralichthys olivaceus: identification and characterization of lymphocyte antigen 75 (Ly75/CD205)

Science.gov (United States)

Yang, Yang; Liu, Qinghua; Ma, Daoyuan; Song, Zongchen; Li, Jun

2018-04-01

Some germ cell marker genes, such as vasa, nanos, and dead end (dnd), have been identified in fish. Recently, lymphocyte antigen 75 (Ly75/CD205) has been identified as a mitotic germ cell-specific cell-surface marker in several fish species. In this study, the Japanese flounder ly75 homolog (ly75) was cloned and its expression pattern in gonads was analyzed. The full-length cDNA of ly75 was 7 346 bp, with an open reading frame (ORF) of 5 229 bp. The ORF encoded a protein containing 1 742 amino acids with a predicted molecular mass of 196.89 kDa. In adult tissues, ly75 transcripts were detected in all analyzed tissues but abundantly in the testis. In in-situ hybridization analyses, ly75 mRNA was predominantly localized in oocytes in the ovary and spermatogonia in the testis, but ly75 mRNA was not detected in oogonia, spermatocytes, spermatids, or spermatozoa. These results indicated that ly75 could be a potential germ cell-specific marker in P. olivaceus, as in other fishes.

CD11b⁺, Ly6G⁺ cells produce type I interferon and exhibit tissue protective properties following peripheral virus infection.

Directory of Open Access Journals (Sweden)

Matthew A Fischer

2011-11-01

Full Text Available The goal of the innate immune system is containment of a pathogen at the site of infection prior to the initiation of an effective adaptive immune response. However, effector mechanisms must be kept in check to combat the pathogen while simultaneously limiting undesirable destruction of tissue resulting from these actions. Here we demonstrate that innate immune effector cells contain a peripheral poxvirus infection, preventing systemic spread of the virus. These innate immune effector cells are comprised primarily of CD11b⁺Ly6C⁺Ly6G⁻ monocytes that accumulate initially at the site of infection, and are then supplemented and eventually replaced by CD11b⁺Ly6C⁺Ly6G⁺ cells. The phenotype of the CD11b⁺Ly6C⁺Ly6G⁺ cells resembles neutrophils, but the infiltration of neutrophils typically occurs prior to, rather than following, accumulation of monocytes. Indeed, it appears that the CD11b⁺Ly6C⁺Ly6G⁺ cells that infiltrated the site of VACV infection in the ear are phenotypically distinct from the classical description of both neutrophils and monocyte/macrophages. We found that CD11b⁺Ly6C⁺Ly6G⁺ cells produce Type I interferons and large quantities of reactive oxygen species. We also observed that depletion of Ly6G⁺ cells results in a dramatic increase in tissue damage at the site of infection. Tissue damage is also increased in the absence of reactive oxygen species, although reactive oxygen species are typically thought to be damaging to tissue rather than protective. These data indicate the existence of a specialized population of CD11b⁺Ly6C⁺Ly6G⁺ cells that infiltrates a site of virus infection late and protects the infected tissue from immune-mediated damage via production of reactive oxygen species. Regulation of the action of this population of cells may provide an intervention to prevent innate immune-mediated tissue destruction.

Identities of P2 and P3 Residues of H-2Kb-Bound Peptides Determine Mouse Ly49C Recognition.

Directory of Open Access Journals (Sweden)

Elsa A Marquez

Full Text Available Ly49 receptors can be peptide selective in their recognition of MHC-I-peptide complexes, affording them a level of discrimination beyond detecting the presence or absence of specific MHC-I allele products. Despite this ability, little is understood regarding the properties that enable some peptides, when bound to MHC-I molecules, to support Ly49 recognition, but not others. Using RMA-S target cells expressing MHC-I molecules loaded with individual peptides and effector cells expressing the ectodomain of the inhibitory Ly49C receptor, we found that two adjacent amino acid residues, P2 and P3, both buried in the peptide binding groove of H-2Kb, determine mouse Ly49C specificity. If both are aliphatic residues, this is supportive. Whereas, small amino acids at P2 and aromatic amino acids at the P3 auxiliary anchor residue are detrimental to Ly49C recognition. These results resemble those with a rat Ly49 where the identity of a peptide anchor residue determines recognition, suggesting that dependence on specific peptide residues buried in the MHC-I peptide-binding groove may be fundamental to Ly49 peptide selectivity and recognition.

Discovery and characterization of LY2784544, a small-molecule tyrosine kinase inhibitor of JAK2V617F

International Nuclear Information System (INIS)

Ma, L; Clayton, J R; Walgren, R A; Zhao, B; Evans, R J; Smith, M C; Heinz-Taheny, K M; Kreklau, E L; Bloem, L; Pitou, C; Shen, W; Strelow, J M; Halstead, C; Rempala, M E; Parthasarathy, S; Gillig, J R; Heinz, L J; Pei, H; Wang, Y; Stancato, L F; Dowless, M S; Iversen, P W; Burkholder, T P

2013-01-01

Owing to the prevalence of the JAK2V617F mutation in myeloproliferative neoplasms (MPNs), its constitutive activity, and ability to recapitulate the MPN phenotype in mouse models, JAK2V617F kinase is an attractive therapeutic target. We report the discovery and initial characterization of the orally bioavailable imidazopyridazine, LY2784544, a potent, selective and ATP-competitive inhibitor of janus kinase 2 (JAK2) tyrosine kinase. LY2784544 was discovered and characterized using a JAK2-inhibition screening assay in tandem with biochemical and cell-based assays. LY2784544 in vitro selectivity for JAK2 was found to be equal or superior to known JAK2 inhibitors. Further studies showed that LY2784544 effectively inhibited JAK2V617F-driven signaling and cell proliferation in Ba/F3 cells (IC 50 =20 and 55 nM, respectively). In comparison, LY2784544 was much less potent at inhibiting interleukin-3-stimulated wild-type JAK2-mediated signaling and cell proliferation (IC 50 =1183 and 1309 nM, respectively). In vivo, LY2784544 effectively inhibited STAT5 phosphorylation in Ba/F3-JAK2V617F-GFP (green fluorescent protein) ascitic tumor cells (TED 50 =12.7 mg/kg) and significantly reduced (P<0.05) Ba/F3-JAK2V617F-GFP tumor burden in the JAK2V617F-induced MPN model (TED 50 =13.7 mg/kg, twice daily). In contrast, LY2784544 showed no effect on erythroid progenitors, reticulocytes or platelets. These data suggest that LY2784544 has potential for development as a targeted agent against JAK2V617F and may have properties that allow suppression of JAK2V617F-induced MPN pathogenesis while minimizing effects on hematopoietic progenitor cells

TRANSITING THE SUN. II. THE IMPACT OF STELLAR ACTIVITY ON Lyα TRANSITS

Energy Technology Data Exchange (ETDEWEB)

Llama, J.; Shkolnik, E. L., E-mail: joe.llama@lowell.edu [Lowell Observatory, 1400 W Mars Hill Road, Flagstaff, AZ 86001 (United States)

2016-01-20

High-energy observations of the Sun provide an opportunity to test the limits of our ability to accurately measure the properties of transiting exoplanets in the presence of stellar activity. Here we insert the transit of a hot Jupiter into continuous disk integrated data of the Sun in Lyα from NASA’s Solar Dynamics Observatory/EVE instrument to assess the impact of stellar activity on the measured planet-to-star radius ratio (R{sub p}/R{sub ⋆}). In 75% of our simulated light curves, we measure the correct radius ratio; however, incorrect values can be measured if there is significant short-term variability in the light curve. The maximum measured value of R{sub p}/R{sub ⋆} is 50% larger than the input value, which is much smaller than the large Lyα transit depths that have been reported in the literature, suggesting that for stars with activity levels comparable to the Sun, stellar activity alone cannot account for these deep transits. We ran simulations without a transit and found that stellar activity cannot mimic the Lyα transit of 55 Cancari b, strengthening the conclusion that this planet has a partially transiting exopshere. We were able to compare our simulations to more active stars by artificially increasing the variability in the Solar Lyα light curve. In the higher variability data, the largest value of R{sub p}/R{sub ⋆} we measured is <3× the input value, which again is not large enough to reproduce the Lyα transit depth reported for the more active stars HD 189733 and GJ 436, supporting the interpretation that these planets have extended atmospheres and possible cometary tails.

X-ray reflection in oxygen-rich accretion discs of ultracompact X-ray binaries

DEFF Research Database (Denmark)

Madej, O. K.; Garcia, Jeronimo; Jonker, P. G.

2014-01-01

We present spectroscopic X-ray data of two candidate ultracompact X-ray binaries (UCXBs): 4U 0614+091 and 4U 1543-624. We confirm the presence of a broad O viii Ly alpha reflection line (at a parts per thousand 18 angstrom) using XMM-Newton and Chandra observations obtained in 2012 and 2013. The ...

[Experimental study on aging effect of Angelica sinensis polysaccharides combined with cytarabine on human leukemia KG1alpha cell lines].

Science.gov (United States)

Xu, Chun-Yan; Geng, Shan; Liu, Jun; Zhu, Jia-Hong; Zhang, Xian-Ping; Jiang, Rong; Wang, Ya-Ping

2014-04-01

The latest findings of our laboratory showed that Angelica sinensis polysaccharide (ASP) showed a definite effect in regulating the aging of hematopoietic stem cells. Leukemia is a type of malignant hematopoietic tumor in hematopoietic stem cells. There have been no relevant reports about ASP's effect in regulating the aging of leukemia cells. In this study, human acute myeloid leukemia (AML) KG1alpha cell lines in logarithmic growth phase were taken as the study object, and were divided into the ASP group, the cytarabine (Ara-C) group, the ASP + Ara-C group and the control group. The groups were respectively treated with different concentration of ASP, Ara-C and ASP + Ara-C for different periods, with the aim to study the effect of ASP combined with Ara-C in regulating the aging of human acute myeloid leukemia KG1alpha cell lines and its relevant mechanism. The results showed that ASP, Ara-C and ASP + Ara-C could obviously inhibit KG1alpha cell proliferation in vitro, block the cells in G0/G1 phase. The cells showed the aging morphological feature. The percentage of positive stained aging cells was dramatically increased, and could significantly up-regulate the expression of aging-related proteins P16 and RB, which were more obvious in the ASP + Ara-C group. In conclusion, the aging mechanism of KG1alpha cell induced by ASP and Ara-C may be related to the regulation of the expression of aging-related proteins, suggesting that the combined administration of ASP and anticancer drugs plays a better role in the treatment of leukemia .

The triply-ionized carbon forest from eBOSS: cosmological correlations with quasars in SDSS-IV DR14

Science.gov (United States)

Blomqvist, Michael; Pieri, Matthew M.; du Mas des Bourboux, Hélion; Busca, Nicolás G.; Slosar, Anže; Bautista, Julian E.; Brinkmann, Jonathan; Brownstein, Joel R.; Dawson, Kyle; de Sainte Agathe, Victoria; Guy, Julien; Percival, Will J.; Pérez-Ràfols, Ignasi; Rich, James; Schneider, Donald P.

2018-05-01

We present measurements of the cross-correlation of the triply-ionized carbon (CIV) forest with quasars using Sloan Digital Sky Survey Data Release 14. The study exploits a large sample of new quasars from the first two years of observations by the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). The CIV forest is a weaker tracer of large-scale structure than the Lyα forest, but benefits from being accessible at redshifts zfit to the quasar-CIV cross-correlations for the CIV forest and the SiIV forest, the CIV redshift-space distortion parameter is βCIV=0.27 ‑0.14 ‑0.26 +0.16 +0.34 and its combination with the CIV linear transmission bias parameter is bCIV(1+βCIV)=‑0.0183 ‑0.0014 ‑0.0029 +0.0013 +0.0025 (1σ and 2σ statistical errors) at the mean redshift z=2.00. Splitting the sample at z=2.2 to constrain the bias evolution with redshift yields the power-law exponent γ=0.60±0.63, indicating a significantly weaker redshift-evolution than for the Lyα forest linear transmission bias. Additionally, we demonstrate that CIV absorption has the potential to be used as a probe of baryon acoustic oscillations (BAO). While the current data set is insufficient for a detection of the BAO peak feature, the final quasar samples for redshifts 1.4

Characterizing the Lyman-alpha forest flux probability distribution function using Legendre polynomials

Science.gov (United States)

Cieplak, Agnieszka; Slosar, Anze

2018-01-01

The Lyman-alpha forest has become a powerful cosmological probe at intermediate redshift. It is a highly non-linear field with much information present beyond the power spectrum. The flux probability flux distribution (PDF) in particular has been a successful probe of small scale physics. However, it is also sensitive to pixel noise, spectrum resolution, and continuum fitting, all of which lead to possible biased estimators. Here we argue that measuring the coefficients of the Legendre polynomial expansion of the PDF offers several advantages over measuring the binned values as is commonly done. Since the n-th Legendre coefficient can be expressed as a linear combination of the first n moments of the field, this allows for the coefficients to be measured in the presence of noise and allows for a clear route towards marginalization over the mean flux. Additionally, in the presence of noise, a finite number of these coefficients are well measured with a very sharp transition into noise dominance. This compresses the information into a small amount of well-measured quantities. Finally, we find that measuring fewer quasars with high signal-to-noise produces a higher amount of recoverable information.

Protection against amphetamine-induced neurotoxicity toward striatal dopamine neurons in rodents by LY274614, an excitatory amino acid antagonist.

Science.gov (United States)

Fuller, R W; Hemrick-Luecke, S K; Ornstein, P L

1992-10-01

LY274614, 3SR,4aRS,6SR,8aRS-6-[phosphonomethyl]decahydr oisoquinoline-3- carboxylic acid, has been described as a potent antagonist of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor. Here its ability to antagonize the prolonged depletion of dopamine in the striatum by amphetamine in iprindole-treated rats is reported. A single 18.4 mg/kg (i.p.) dose of (+/-)-amphetamine hemisulfate, given to rats pretreated with iprindole, resulted in persistent depletion of dopamine in the striatum 1 week later. This prolonged depletion of dopamine in the striatum was antagonized by dizocilpine (MK-801, a non-competitive antagonist of NMDA receptors) or by LY274614 (a competitive antagonist of NMDA receptors). The protective effect of LY274614 was dose-dependent, being maximum at 10-40 mgkg (i.p.). A 10 mg/kg dose of LY274614 was effective in antagonizing the depletion of dopamine in the striatum, when given as long as 8 hr prior to amphetamine but not when given 24 hr prior to amphetamine. Depletion of dopamine in the striatum was also antagonized when LY274614 was given after the injection of amphetamine; LY274614 protected when given up to 4 hr after but not when given 8 or 24 hr after amphetamine. The prolonged depletion of dopamine in the striatum in mice, given multiple injections of methamphetamine, was also antagonized dose-dependently and completely by LY274614. The data strengthen the evidence that the neurotoxic effect of amphetamine and related compounds toward nigrostriatal dopamine neurons involves NMDA receptors and that LY274614 is an NMDA receptor antagonist with long-lasting in vivo effects in rats.

Isolating the Lyman alpha forest BAO anomaly

Energy Technology Data Exchange (ETDEWEB)

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

2017-04-01

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

Stagnation and interpenetration of laser-created colliding plasmas

Energy Technology Data Exchange (ETDEWEB)

Pollaine, S.M.; Albritton, J.R.; Kauffman, R.; Keane, C.J. (Lawrence Livermore National Lab., CA (USA)); Berger, R.L.; Bosch, R.; Delameter, N.D.; Failor, B.H. (KMS Fusion, Inc., Ann Arbor, MI (USA))

1990-11-05

A KMS laser experiment collides Aluminum (A1) and Magnesium (Mg) plasmas. The measurements include electron density, time and space resolved Ly-alpha and He-alpha lines of Al and Mg, and x-ray images. These measurements were analyzed with a hydrodynamic code, LASNEX, and a special two-fluid code OFIS. The results strongly suggest that at early times, the Al interpenetrates the counterstreaming Mg and deposits in the dense Mg region. At late times, the Al plasma stagnates against the Mg plasma.

ALMA OBSERVATIONS OF Ly α BLOB 1: HALO SUBSTRUCTURE ILLUMINATED FROM WITHIN

Energy Technology Data Exchange (ETDEWEB)

Geach, J. E. [Centre for Astrophysics Research, University of Hertfordshire, Hatfield, AL10 9AB (United Kingdom); Narayanan, D. [Dept. of Physics and Astronomy, Haverford College, PA 19041 (United States); Matsuda, Y.; Ao, Y.; Kubo, M. [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Hayes, M. [Stockholm University, Dept. of Astronomy and Oskar Klein Centre for Cosmoparticle Physics, SE-10691, Stockholm (Sweden); Mas-Ribas, Ll.; Dijkstra, M. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Steidel, C. C. [California Institute of Technology, 1216 East California Boulevard, MS 249-17, Pasadena, CA 91125 (United States); Chapman, S. C. [Dept. of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 4R2 (Canada); Feldmann, R. [Dept. of Astronomy, University of California Berkeley, CA 94720 (United States); Avison, A. [UK ALMA Regional Centre Node, Manchester (United Kingdom); Agertz, O. [Dept. of Physics, University of Surrey, GU2 7XH, Surrey (United Kingdom); Birkinshaw, M.; Bremer, M. N. [H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL (United Kingdom); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Dannerbauer, H. [Instituto de Astrofísica de Canarias, La Laguna, Tenerife (Spain); Farrah, D. [Dept. of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Harrison, C. M. [Centre for Extragalactic Astronomy, Dept. of Physics, Durham University, South Road, Durham, DH1 3LE (United Kingdom); Michałowski, M. J., E-mail: j.geach@herts.ac.uk [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom); and others

2016-11-20

We present new Atacama Large Millimeter/Submillimeter Array (ALMA) 850 μ m continuum observations of the original Ly α Blob (LAB) in the SSA22 field at z = 3.1 (SSA22-LAB01). The ALMA map resolves the previously identified submillimeter source into three components with a total flux density of S {sub 850} = 1.68 ± 0.06 mJy, corresponding to a star-formation rate of ∼150 M {sub ⊙} yr{sup -1}. The submillimeter sources are associated with several faint ( m ≈ 27 mag) rest-frame ultraviolet sources identified in Hubble Space Telescope Imaging Spectrograph (STIS) clear filter imaging ( λ ≈ 5850 Å). One of these companions is spectroscopically confirmed with the Keck Multi-Object Spectrometer For Infra-Red Exploration to lie within 20 projected kpc and 250 km s{sup -1} of one of the ALMA components. We postulate that some of these STIS sources represent a population of low-mass star-forming satellites surrounding the central submillimeter sources, potentially contributing to their growth and activity through accretion. Using a high-resolution cosmological zoom simulation of a 10{sup 13} M {sub ⊙} halo at z = 3, including stellar, dust, and Ly α radiative transfer, we can model the ALMA+STIS observations and demonstrate that Ly α photons escaping from the central submillimeter sources are expected to resonantly scatter in neutral hydrogen, the majority of which is predicted to be associated with halo substructure. We show how this process gives rise to extended Ly α emission with similar surface brightness and morphology to observed giant LABs.

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-06-01

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

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

International Nuclear Information System (INIS)

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

2017-01-01

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

More than Solfège and Hand Signs: Philosophy, Tools, and Lesson Planning in the Authentic Kodály Classroom

Science.gov (United States)

Bowyer, James

2015-01-01

Four components of the Kodály concept are delineated here: philosophy, objectives, essential tools, and lesson planning process. After outlining the tenets of the Kodály philosophy and objectives, the article presents the Kodály concept's essential tools, including singing, movable "do" solfège, rhythm syllables, hand signs, singing on…

PG 0308 + 096 and PG 1026 + 002 - Two new short period binary stars resulting from common-envelope evolution

Science.gov (United States)

Saffer, Rex A.; Wade, Richard A.; Liebert, James; Green, Richard F.; Sion, Edward M.; Bechtold, J.; Foss, Diana; Kidder, K.

1993-01-01

Ultraviolet spectroscopy, optical spectroscopy, and spectrophotometry have been used to study the excess UV stars PG 0308 + 096 and PG 1026 + 002. Both objects are short-period binary systems, each containing a DA white dwarf star and a dM star. Orbital periods of approximately 0.284 day for PG 0308 + 096, and aproximately 0.597 day for PG 1026, have been found by spectroscopic analysis of the H-alpha emission line. Ly-alpha and Balmer line profile fitting were used to estimate the mass of white dwarf stars; mass estimates for the dM stars are based on their spectral types. The orbital inclinations are derived from these masses, the periods, and amplitudes of the H-alpha radial velocity curves. The equivalent width of the H-alpha emission line, in each binary system, varies with the orbital phase in such a manner as to imply that it arises, in large part at least, from the hemisphere of the M star that faces the white dwarf star.

Generation of a human immunodeficiency virus type 1 chronically infected monkey B cell line expressing low levels of endogenous TRIM5alpha.

Science.gov (United States)

Ridolfi, Barbara; Catone, Stefania; Sgarbanti, Marco; Sernicola, Leonardo; Battistini, Angela; Parolin, Cristina; Titti, Fausto; Borsetti, Alessandra

2009-12-01

Several innate cellular antiviral factors exist in mammalian cells that prevent the replication of retroviruses. Among them, the tripartite motif protein (TRIM)5alpha has been shown to block human immunodeficiency virus type 1 (HIV-1) infection in several types of Old World monkey cells. Here we report a novel HIV-1 chronically infected monkey B cell line, F6/HIV-1, characterized by very low levels of TRIM5alpha expression that allows HIV-1 to overcome the restriction. Virus produced by F6/HIV-1 cells fails to infect monkey cells but retains the ability to infect human peripheral blood mononuclear cells (PBMCs) and T cell lines, although with a reduced infectivity compared to the input virus. Ultrastructural analyses revealed the presence of budding virions at the F6/HIV-1 cells plasma membrane characterized by a typical conical core shell. To our knowledge F6/HIV-1 is the first monkey cell line chronically infected by HIV-1 and able to release infectious particles thus representing a useful tool to gain further insights into the molecular mechanisms of HIV-1 pathogenesis.

Early-type semidetached system LY Aurigae

International Nuclear Information System (INIS)

Li, Y.F.; Leung, K.C.

1985-01-01

In an effort to resolve a controversy regarding the configuration, mass ratio, and evolutionary status of the early-type close binary system LY Aur, the six bandpass OAO 2 observations of Heap and the ground-based observations combined by Eaton were analyzed. The Wilson and Devinney approach was used. The system is found to be semidetached, with the cooler and less massive component filling its Roche lobe, while the hotter component is close to its Roche surface. The system is not an early-type zero-age contact, as was suspected earlier. 20 references

Lyα EMITTERS IN HIERARCHICAL GALAXY FORMATION. II. ULTRAVIOLET CONTINUUM LUMINOSITY FUNCTION AND EQUIVALENT WIDTH DISTRIBUTION

International Nuclear Information System (INIS)

Kobayashi, Masakazu A. R.; Totani, Tomonori; Nagashima, Masahiro

2010-01-01

We present theoretical predictions of the UV continuum luminosity function (UV LF) and Lyα equivalent width (EW) distribution of Lyα emitters (LAEs) in the framework of the hierarchical clustering model of galaxy formation. The model parameters for the LAEs were determined by fitting to the observed Lyα LF at z = 5.7 in our previous study, and the fit indicates that extinction of Lyα photons by dust is significantly less effective than that of UV continuum photons, implying a clumpy dust distribution in the interstellar medium. We then compare the predictions about UV LFs and EW distributions with a variety of observations at z∼ 3-6, allowing no more free parameters and paying careful attention to the selection conditions of LAEs in each survey. We find that the predicted UV LFs and EW distributions are in nice agreement with observed data, and especially, our model naturally reproduces the existence of large EW LAEs (∼> 240 A) without introducing Pop III stars or top-heavy initial mass function. We show that both the stellar population (young age and low metallicity) and extinction by clumpy dust are the keys to reproducing large EW LAEs. The evidence of EW enhancement by clumpy dust is further strengthened by the quantitative agreement between our model and recent observations about a positive correlation between EW and extinction. The observed trend that brighter LAEs in the UV continuum tend to have smaller mean EW is also reproduced, and the clumpy dust plays an important role again for this trend. We suggested in our previous study that the transmission of the intergalactic medium for Lyα emission rapidly decreases from z ∼ 6 to 7 by fitting to Lyα LFs, and this evidence is quantitatively strengthened by the comparison with the UV LF and EW distribution at z ∼ 6.6.

Probing natural killer cell education by Ly49 receptor expression analysis and computational modelling in single MHC class I mice.

Directory of Open Access Journals (Sweden)

Sofia Johansson

Full Text Available Murine natural killer (NK cells express inhibitory Ly49 receptors for MHC class I molecules, which allows for "missing self" recognition of cells that downregulate MHC class I expression. During murine NK cell development, host MHC class I molecules impose an "educating impact" on the NK cell pool. As a result, mice with different MHC class I expression display different frequency distributions of Ly49 receptor combinations on NK cells. Two models have been put forward to explain this impact. The two-step selection model proposes a stochastic Ly49 receptor expression followed by selection for NK cells expressing appropriate receptor combinations. The sequential model, on the other hand, proposes that each NK cell sequentially expresses Ly49 receptors until an interaction of sufficient magnitude with self-class I MHC is reached for the NK cell to mature. With the aim to clarify which one of these models is most likely to reflect the actual biological process, we simulated the two educational schemes by mathematical modelling, and fitted the results to Ly49 expression patterns, which were analyzed in mice expressing single MHC class I molecules. Our results favour the two-step selection model over the sequential model. Furthermore, the MHC class I environment favoured maturation of NK cells expressing one or a few self receptors, suggesting a possible step of positive selection in NK cell education. Based on the predicted Ly49 binding preferences revealed by the model, we also propose, that Ly49 receptors are more promiscuous than previously thought in their interactions with MHC class I molecules, which was supported by functional studies of NK cell subsets expressing individual Ly49 receptors.

Detection of Three-minute Oscillations in Full-disk Ly α Emission during a Solar Flare

Energy Technology Data Exchange (ETDEWEB)

Milligan, Ryan O.; Fletcher, Lyndsay [SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom); Fleck, Bernhard [ESA Directorate of Science, Operations Department, c/o NASA/GSFC Code 671, Greenbelt, MD 20071 (United States); Ireland, Jack; Dennis, Brian R. [Solar Physics Laboratory (Code 671), Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2017-10-10

In this Letter we report the detection of chromospheric 3-minute oscillations in disk-integrated EUV irradiance observations during a solar flare. A wavelet analysis of detrended Ly α (from GOES /EUVS) and Lyman continuum (from Solar Dynamics Observatory ( SDO )/EVE) emission from the 2011 February 15 X-class flare (SOL2011-02-15T01:56) revealed a ∼3 minute period present during the flare’s main phase. The formation temperature of this emission locates this radiation at the flare’s chromospheric footpoints, and similar behavior is found in the SDO /Atmospheric Imaging Assembly 1600 and 1700 Å channels, which are dominated by chromospheric continuum. The implication is that the chromosphere responds dynamically at its acoustic cutoff frequency to an impulsive injection of energy. Since the 3-minute period was not found at hard X-ray (HXR) energies (50–100 keV) in Reuven Ramaty High Energy Solar Spectroscopic Imager data we can state that this 3-minute oscillation does not depend on the rate of energization of non-thermal electrons. However, a second period of 120 s found in both HXR and chromospheric lightcurves is consistent with episodic electron energization on 2-minute timescales. Our finding on the 3-minute oscillation suggests that chromospheric mechanical energy should be included in the flare energy budget, and the fluctuations in the Ly α line may influence the composition and dynamics of planetary atmospheres during periods of high activity.

Cellular determinants of the inverse cross sensitivity of mouse lymphoma L5178Y cell lines to ionizing radiation and hydrogen peroxide; Podloze odwrotnej krzyzowej opornosci komorek L5178Y na promieniowanie jonizujace i nadtlenek wodoru

Energy Technology Data Exchange (ETDEWEB)

Kruszewski, M [Dept. of Radiobiology and Health Protection, Inst. of Nuclear Chemistry and Technology, Warsaw (Poland)

1999-07-01

The pair of L5178Y sublines (LY-R and LY-S) is exceptional among mammalian cell lines because of their unique inverse cross-sensitivity to ionizing radiation and hydrogen peroxide. The high sensitivity of LY-S cells to ionizing radiation is reasonably explained by the impairment of DNA double strand breaks rejoining. Although the enzymatic defect of LY-S cells is not yet identified, the more pronounced effect of DNA-dependent protein kinase (DNA-PK) inhibitor (OK-1035) on DNA damage repair after 8 Gy x-irradiation in LY-R cells than in LY-S cells, suggests that LY-S cells may be defective in DNA-PK activity or in the other enzymatic activities downstream from DNA-PK. An additional feature is a higher protection of DNA against ionizing radiation by nuclear proteins in LY-R cells. These data support the concept that nuclear matrix organization may contribute to the cellular susceptibility to DNA damaging agents. Ionizing radiation-sensitive LY-S cells suffer also more DNA base damage than ionizing radiation-resistant LY-R cells. However, the repair rates of the {gamma}-ray-induced DNA base damage in LY sublines are related neither to the initial amounts of the damaged bases nor to the lethal or mutagenic effects of ionizing radiation. In contrast, hydrogen peroxide (H{sub 2}O{sub 2}) sensitive LY-R cells suffer more DNA base damage after H{sub 2}O{sub 2} treatment. This may be due to the lower activity of catalase and/or the lower level of glutathione and other monobromobimane-reactive thiols in LY-R cells than in LY-S cells. However, the main cause of LY-R cells' sensitivity to H{sub 2}O{sub 2} seems to be a higher iron ion content in these cells as compared to LY-S cells. A higher content of iron ions and a higher iron:copper ratio is found in isolated nuclei of LY-R cells than in those of LY-S cells. This is further confirmed by a higher ''labile iron'' pool in LY-R cells than in LY-S cells. Further evidence of different ions content in LY cells and its influence

The MUSE-Wide survey: a measurement of the Ly α emitting fraction among z > 3 galaxies

Science.gov (United States)

Caruana, Joseph; Wisotzki, Lutz; Herenz, Edmund Christian; Kerutt, Josephine; Urrutia, Tanya; Schmidt, Kasper Borello; Bouwens, Rychard; Brinchmann, Jarle; Cantalupo, Sebastiano; Carollo, Marcella; Diener, Catrina; Drake, Alyssa; Garel, Thibault; Marino, Raffaella Anna; Richard, Johan; Saust, Rikke; Schaye, Joop; Verhamme, Anne

2018-01-01

We present a measurement of the fraction of Lyman α (Ly α) emitters (XLy α) amongst HST continuum-selected galaxies at 3 Multi-Unit Spectroscopic Explorer (MUSE) on the VLT. Making use of the first 24 MUSE-Wide pointings in GOODS-South, each having an integration time of 1 h, we detect 100 Ly α emitters and find XLy α ≳ 0.5 for most of the redshift range covered, with 29 per cent of the Ly α sample exhibiting rest equivalent widths (rest-EWs) ≤ 15 Å. Adopting a range of rest-EW cuts (0-75 Å), we find no evidence of a dependence of XLy α on either redshift or ultraviolet luminosity.

Non-LTE hydrogen-line formation in moving prominences

Science.gov (United States)

Heinzel, P.; Rompolt, B.

1986-01-01

The behavior of hydrogen-line brightness variations, depending on the prominence-velocity changes were investigated. By solving the NON-Local thermodynamic equilibrium (LTE) problem for hydrogen researchers determine quantitatively the effect of Doppler brightening and/or Doppler dimming (DBE, DDE) in the lines of Lyman and Balmer series. It is demonstrated that in low-density prominence plasmas, DBE in H alpha and H beta lines can reach a factor of three for velocities around 160 km/sec, while the L alpha line exhibits typical DDE. L beta brightness variations follow from a combined DBE in the H alpha and DDE in L alpha and L beta itself, providing that all relevant multilevel interlocking processes are taken into account.

Effects of rearing environment on the gut antimicrobial responses of two broiler chicken lines.

Science.gov (United States)

Butler, Vanessa L; Mowbray, Catherine A; Cadwell, Kevin; Niranji, Sherko S; Bailey, Richard; Watson, Kellie A; Ralph, John; Hall, Judith

2016-10-01

To reduce the risk of enteric disease in poultry, knowledge of how bird gut innate defences mature with age while also responding to different rearing environments is necessary. In this study the gut innate responses of two phylogenetically distinct lines of poultry raised from hatch to 35days, in conditions mimicing high hygiene (HH) and low hygiene (LH) rearing environments, were compared. Analyses focussed on the proximal gut antimicrobial activities and the duodenal and caecal AvBD1, 4 and 10 defensin profiles. Variability in microbial killing was observed between individual birds in each of the two lines at all ages, but samples from day 0 birds (hatch) of both lines exhibited marked killing properties, Line X: 19±11% (SEM) and Line Y: 8.5±12% (SEM). By day 7 a relaxation in killing was observed with bacterial survival increased from 3 (Line Y (LY)) to 11 (Line X (LX)) fold in birds reared in the HH environment. A less marked response was observed in the LH environment and delayed until day 14. At day 35 the gut antimicrobial properties of the two lines were comparable. The AvBD 1, 4 and 10 data relating to the duodenal and caecal tissues of day 0, 7 and 35 birds LX and LY birds revealed gene expression trends specific to each line and to the different rearing environments although the data were confounded by inter-individual variability. In summary elevated AvBD1 duodenal expression was detected in day 0 and day 7 LX, but not LY birds, maintained in LH environments; Line X and Y duodenal AvBD4 profiles were detected in day 7 birds reared in both environments although duodenal AvBD10 expression was less sensitive to bird age and rearing background. Caecal AvBD1 expression was particularly evident in newly hatched birds. These data suggest that proximal gut antimicrobial activity is related to the bird rearing environments although the roles of the AvBDs in such activities require further investigation. Copyright © 2016. Published by Elsevier B.V.

The BigBoss Experiment

Energy Technology Data Exchange (ETDEWEB)

Schelgel, D.; Abdalla, F.; Abraham, T.; Ahn, C.; Allende Prieto, C.; Annis, J.; Aubourg, E.; Azzaro, M.; Bailey, S.; Baltay, C.; Baugh, C.; Bebek, C.; Becerril, S.; Blanton, M.; Bolton, A.; Bromley, B.; Cahn, R.; Carton, P.-H.; Cervanted-Cota, J.L.; Chu, Y.; Cortes, M.; /APC, Paris /Brookhaven /IRFU, Saclay /Marseille, CPPM /Marseille, CPT /Durham U. / /IEU, Seoul /Fermilab /IAA, Granada /IAC, La Laguna / /IAC, Mexico / / /Madrid, IFT /Marseille, Lab. Astrophys. / / /New York U. /Valencia U.

2012-06-07

BigBOSS is a Stage IV ground-based dark energy experiment to study baryon acoustic oscillations (BAO) and the growth of structure with a wide-area galaxy and quasar redshift survey over 14,000 square degrees. It has been conditionally accepted by NOAO in response to a call for major new instrumentation and a high-impact science program for the 4-m Mayall telescope at Kitt Peak. The BigBOSS instrument is a robotically-actuated, fiber-fed spectrograph capable of taking 5000 simultaneous spectra over a wavelength range from 340 nm to 1060 nm, with a resolution R = {lambda}/{Delta}{lambda} = 3000-4800. Using data from imaging surveys that are already underway, spectroscopic targets are selected that trace the underlying dark matter distribution. In particular, targets include luminous red galaxies (LRGs) up to z = 1.0, extending the BOSS LRG survey in both redshift and survey area. To probe the universe out to even higher redshift, BigBOSS will target bright [OII] emission line galaxies (ELGs) up to z = 1.7. In total, 20 million galaxy redshifts are obtained to measure the BAO feature, trace the matter power spectrum at smaller scales, and detect redshift space distortions. BigBOSS will provide additional constraints on early dark energy and on the curvature of the universe by measuring the Ly-alpha forest in the spectra of over 600,000 2.2 < z < 3.5 quasars. BigBOSS galaxy BAO measurements combined with an analysis of the broadband power, including the Ly-alpha forest in BigBOSS quasar spectra, achieves a FOM of 395 with Planck plus Stage III priors. This FOM is based on conservative assumptions for the analysis of broad band power (k{sub max} = 0.15), and could grow to over 600 if current work allows us to push the analysis to higher wave numbers (k{sub max} = 0.3). BigBOSS will also place constraints on theories of modified gravity and inflation, and will measure the sum of neutrino masses to 0.024 eV accuracy.

Modeling the location of the forest line in northeast European Russia with remotely sensed vegetation and GIS-based climate and terrain data

DEFF Research Database (Denmark)

Virtanen, Tarmo; Mikkola, Kari; Nikula, Ari

2004-01-01

GIS-based data sets were used to analyze the structure of the forest line at the landscape level in the lowlands of the Usa River Basin, in northeast European Russia. Vegetation zones in the area range from taiga in the south to forest-tundra and tundra in the north. We constructed logistic...

Delayed K562 cell apoptosis promoted by cleaved LyGDI after 60Co γ-rays irradiation

International Nuclear Information System (INIS)

Sun Huali; Duan Weiming; Shao Yanyan; Xiao Hainan; Zhou Xinwen

2010-01-01

Objective: To elucidate the function and regulatory mechanism of LyGDI involved delayed cell death in the human K562 cells and HL-60 cells induced by 60 Co γ-rays. Methods: Erythrosine B cells staining was used to count the apoptosis rate. PI staining and flow cytometry were applied to check the cell cycle. The expression of LYGDI and Rac1 was resolved by Western blot by using monoclonal antibody of LyGDI and Rac1. The distribution of Rac1 protein in cells was observed with immunofluorescence by using the confocal microscope. Results: The K562 cells showed G 2 /M phase arrest and the percent age was 71.3%. The apoptosis rate was very low at early post-irradiation stage in the K562 cells. The apoptosis rate was 14% in the K562 cells at 24 h post-irradiation with 8 Gy of γ-rays, and delayed cell apoptosis was present. LyGDI was cleaved in the K562 cells irradiated by 4 Gy 60 Co γ-rays after 24 hours post-irradiation. The expression of Rac1 protein was not altered at all, but the distribution was changed in the irradiated cells while the Rac1 protein moved to cell membrane and a little in cell nucleus. The Rac1 was activated with the losing the binding affinity with the LyGDI. Conclusion: LyGDI could promote the delayed cell apoptosis, which is through the activation of the Rac1. (authors)

Alpha spectrometry of thick sources. I. Application to alpha emitters determination

International Nuclear Information System (INIS)

Acena, M.L.; Garcia-Torano, E.; Rivero, M.C.

1977-01-01

A method for determining alpha emitters by silicon surface barrier detector spectroscopy using thick sources is studied. Two types of spectra have been obtained. They have different shapes of line according to the procedure used for preparing the sources. For both spectra a computing least square programme has been developed. In this way it is possible to calculate line intensities with accuracy better than 20 percent. (author) [es

Study of liquid scintillator in detecting the PMN-CL, Ly-CL and extracellular matrix in liver fibrosis

International Nuclear Information System (INIS)

Li Tianxing; Cao Rui; Liang Qizhong; Zou Xiaowei

1997-01-01

Chemiluminescence (CL) of polymorphonuclear (PMN) and lymphocyte(Ly) in blood of patients with cirrhosis has two peaks. Basic peak value of PMN-CL and Ly-CL is increased, the maximal peak values of Zym-PMN and PHA-Ly are decreased, phagolyosis and opsonic function is also decreased, extracellular matrix (ECM) is all increased, HA is positively correlated with 'child' sort (r = 0.96, A>B>C). It suggests that OR is produced and released during CL and superoxide phosphatides is produced by OR in ECM of cirrhosis. It injures the membrane of cells and tissue. Analysis of CL is aided to study the development mechanism of liver fibrosis

NEBULAR ATTENUATION IN H{alpha}-SELECTED STAR-FORMING GALAXIES AT z = 0.8 FROM THE NewH{alpha} SURVEY

Energy Technology Data Exchange (ETDEWEB)

Momcheva, Ivelina G. [Astronomy Department, Yale University, New Haven, CT 06511 (United States); Lee, Janice C.; Ouchi, Masami [Carnegie Observatories, Pasadena, CA 91101 (United States); Ly, Chun [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Salim, Samir [Astronomy Department, Indiana University, Bloomington, IN 47405 (United States); Dale, Daniel A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Finn, Rose [Physics Department, Siena College, Loudonville, NY 12211 (United States); Ono, Yoshiaki, E-mail: ivelina.momcheva@yale.edu [Department of Astronomy, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2013-02-01

We present measurements of the dust attenuation of H{alpha}-selected emission-line galaxies at z = 0.8 from the NewH{alpha} narrowband survey. The analysis is based on deep follow-up spectroscopy with Magellan/IMACS, which captures the strong rest-frame optical emission lines from [O II] {lambda}3727 to [O III] {lambda}5007. The spectroscopic sample used in this analysis consists of 341 confirmed H{alpha} emitters. We place constraints on the active galactic nucleus (AGN) fraction using diagnostics that can be applied at intermediate redshift. We find that at least 5% of the objects in our spectroscopic sample can be classified as AGNs and 2% are composite, i.e., powered by a combination of star formation and AGN activity. We measure the dust attenuation for individual objects from the ratios of the higher order Balmer lines. The H{beta} and H{gamma} pair of lines is detected with S/N > 5 in 55 individual objects and the H{beta} and H{delta} pair is detected in 50 individual objects. We also create stacked spectra to probe the attenuation in objects without individual detections. The median attenuation at H{alpha} based on the objects with individually detected lines is A(H{alpha}) = 0.9 {+-} 1.0 mag, in good agreement with the attenuation found in local samples of star-forming galaxies. We find that the z = 0.8 galaxies occupy a similar locus of attenuation as a function of magnitude, mass, and star formation rate (SFR) as a comparison sample drawn from the SDSS DR4. Both the results from the individual z = 0.8 galaxies and from the stacked spectra show consistency with the mass-attenuation and SFR-attenuation relations found in the local universe, indicating that these relations are also applicable at intermediate redshift.

The low-ion QSO absorption-line systems

International Nuclear Information System (INIS)

Lanzetta, K.M.

1988-01-01

Various techniques are used to investigate the class of QSO absorption-line systems that exhibit low-ion absorption lines. Four separate investigations are conducted as follows: Spectroscopy of 32 QSOs at red wavelengths is presented and used to investigate intermediate-redshift MgII absorption. A total of 22 Mg II doublets are detected, from which properties of the Mg II absorbers are derived. Marginal evidence for intrinsic evolution of the number density of the Mg II absorbers with redshift is found. The data are combined with previous observations of C IV and C II seen in the same QSOs at blue wavelengths, and the properties of Mg II- and C IV-selected systems are compared. A sample is constructed of 129 QSOs for which are available published data suitable for detecting absorption-line systems that are optically thick to Lyman continuum radiation. A total of 53 such Lyman-limit systems are found, from which properties of the Lyman-limit systems are derived. It is found that the rate of incidence of the systems does not strongly evolved with redshift. This result is contrasted with the evolution found previously for systems selected on the basis of Mg II absorption. Spectroscopy at red wavelengths of eight QSOs with known damped Lyα absorption systems is presented. Spectroscopic and spectrophotometric observations aimed at detecting molecular hydrogen and dust in the z = 2.796 damped Lyα absorber toward Q1337 + 113 are presented

Interaktiivne võrguõpik "Võnkumised ja lained" / Ly Sõõrd

Index Scriptorium Estoniae

Sõõrd, Ly

2000-01-01

Interaktiivne võrguõpik "Võnkumised ja lained" on mõeldud gümnaasiumi 10. kl. füüsikakursuse osa "Mehaanilised võnkumised ja lained" õppimiseks iseseisvalt interneti vahendusel ning asub aadressil : http://www.physic.ut.ee/̃ly/xklass/opik.html

Mouse NK cell-mediated rejection of bone marrow allografts exhibits patterns consistent with Ly49 subset licensing.

Science.gov (United States)

Sun, Kai; Alvarez, Maite; Ames, Erik; Barao, Isabel; Chen, Mingyi; Longo, Dan L; Redelman, Doug; Murphy, William J

2012-02-09

Natural killer (NK) cells can mediate the rejection of bone marrow allografts and exist as subsets based on expression of inhibitory/activating receptors that can bind MHC. In vitro data have shown that NK subsets bearing Ly49 receptors for self-MHC class I have intrinsically higher effector function, supporting the hypothesis that NK cells undergo a host MHC-dependent functional education. These subsets also play a role in bone marrow cell (BMC) allograft rejection. Thus far, little in vivo evidence for this preferential licensing across mouse strains with different MHC haplotypes has been shown. We assessed the intrinsic response potential of the different Ly49(+) subsets in BMC rejection by using β2-microglobulin deficient (β2m(-/-)) mice as donors. Using congenic and allogeneic mice as recipients and depleting the different Ly49 subsets, we found that NK subsets bearing Ly49s, which bind "self-MHC" were found to be the dominant subset responsible for β2m(-/-) BMC rejection. This provides in vivo evidence for host MHC class I-dependent functional education. Interestingly, all H2(d) strain mice regardless of background were able to resist significantly greater amounts of β2m(-/-), but not wild-type BMC than H2(b) mice, providing evidence that the rheostat hypothesis regarding Ly49 affinities for MHC and NK-cell function impacts BMC rejection capability.

DISCOVERY OF MASSIVE, MOSTLY STAR FORMATION QUENCHED GALAXIES WITH EXTREMELY LARGE Lyα EQUIVALENT WIDTHS AT z ∼ 3

Energy Technology Data Exchange (ETDEWEB)

Taniguchi, Yoshiaki; Kajisawa, Masaru; Kobayashi, Masakazu A. R.; Nagao, Tohru; Shioya, Yasuhiro [Research Center for Space and Cosmic Evolution, Ehime University, Bunkyo-cho, Matsuyama 790-8577 (Japan); Scoville, Nick Z.; Capak, Peter L. [Department of Astronomy, California Institute of Technology, MS 105-24, Pasadena, CA 91125 (United States); Sanders, David B. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Koekemoer, Anton M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Toft, Sune [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Mariesvej 30, DK-2100 Copenhagen (Denmark); McCracken, Henry J. [Institut d’Astrophysique de Paris, UMR7095 CNRS, Université Pierre et Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France); Le Fèvre, Olivier; Tasca, Lidia; Ilbert, Olivier [Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille), UMR 7326, F-13388 Marseille (France); Sheth, Kartik [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Renzini, Alvio [Dipartimento di Astronomia, Universita di Padova, vicolo dell’Osservatorio 2, I-35122 Padua (Italy); Lilly, Simon; Carollo, Marcella; Kovač, Katarina [Department of Physics, ETH Zurich, 8093 Zurich (Switzerland); Schinnerer, Eva, E-mail: tani@cosmos.phys.sci.ehime-u.ac.jp [MPI for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); and others

2015-08-10

We report a discovery of six massive galaxies with both extremely large Lyα equivalent widths (EWs) and evolved stellar populations at z ∼ 3. These MAssive Extremely STrong Lyα emitting Objects (MAESTLOs) have been discovered in our large-volume systematic survey for strong Lyα emitters (LAEs) with 12 optical intermediate-band data taken with Subaru/Suprime-Cam in the COSMOS field. Based on the spectral energy distribution fitting analysis for these LAEs, it is found that these MAESTLOs have (1) large rest-frame EWs of EW{sub 0} (Lyα) ∼ 100–300 Å, (2) M{sub ⋆} ∼ 10{sup 10.5}–10{sup 11.1} M{sub ⊙}, and (3) relatively low specific star formation rates of SFR/M{sub ⋆} ∼ 0.03–1 Gyr{sup −1}. Three of the six MAESTLOs have extended Lyα emission with a radius of several kiloparsecs, although they show very compact morphology in the HST/ACS images, which correspond to the rest-frame UV continuum. Since the MAESTLOs do not show any evidence for active galactic nuclei, the observed extended Lyα emission is likely to be caused by a star formation process including the superwind activity. We suggest that this new class of LAEs, MAESTLOs, provides a missing link from star-forming to passively evolving galaxies at the peak era of the cosmic star formation history.

Observations of chromospheric lines from OSO-8

Science.gov (United States)

Grossmann-Doerth, U.; Kneer, F.; Uexkuell, M.; Artzner, G. E.; Vial, J. C.

1980-01-01

Results of OSO-8 measurements of the line profiles of the solar Lyman alpha, Ca II K and Mg II k lines are presented. Observations were obtained with the Laboratoire de Physique Stellaire et Planetaire spectrometer at spectral resolutions of 0.25 and 0.060 A for Lyman alpha and 0.025 A for the Mg II and Ca II lines. The Lyman alpha profiles are found to be highly variable according to spatial position with the intensities of the three lines well correlated, and confirm previous observations of the quiet solar chromosphere. Data suggest that the quiet chromosphere is a dynamical phenomenon whose description in terms of a static model atmosphere is only qualitatively valid at best.

Chemical dampening of Ly6C(hi) monocytes in the periphery produces anti-depressant effects in mice.

Science.gov (United States)

Zheng, Xiao; Ma, Sijing; Kang, An; Wu, Mengqiu; Wang, Lin; Wang, Qiong; Wang, Guangji; Hao, Haiping

2016-01-19

The involvement of systemic immunity in depression pathogenesis promises a periphery-targeting paradigm in novel anti-depressant discovery. However, relatively little is known about druggable targets in the periphery for mental and behavioral control. Here we report that targeting Ly6C(hi) monocytes in blood can serve as a strategy for anti-depressant purpose. A natural compound, ginsenoside Rg1 (Rg1), was firstly validated as a periphery-restricted chemical probe. Rg1 selectively suppressed Ly6C(hi) monocytes recruitment to the inflamed mice brain. The proinflammatory potential of Ly6C(hi) monocytes to activate astrocytes was abrogated by Rg1, which led to a blunted feedback release of CCL2 to recruit the peripheral monocytes. In vitro study demonstrated that Rg1 pretreatment on activated THP-1 monocytes retarded their ability to trigger CCL2 secretion from co-cultured U251 MG astrocytes. CCL2-triggered p38/MAPK and PI3K/Akt activation were involved in the action of Rg1. Importantly, in mice models, we found that dampening Ly6C(hi) monocytes at the periphery ameliorated depression-like behavior induced by neuroinflammation or chronic social defeat stress. Together, our work unravels that blood Ly6C(hi) monocytes may serve as the target to enable remote intervention on the depressed brain, and identifies Rg1 as a lead compound for designing drugs targeting peripheral CCL2 signals.

Taraxacum officinale induces cytotoxicity through TNF-alpha and IL-1alpha secretion in Hep G2 cells.

Science.gov (United States)

Koo, Hyun-Na; Hong, Seung-Heon; Song, Bong-Keun; Kim, Cheorl-Ho; Yoo, Young-Hyun; Kim, Hyung-Min

2004-01-16

Taraxacum officinale (TO) has been frequently used as a remedy for women's disease (e.g. breast and uterus cancer) and disorders of the liver and gallbladder. Several earlier studies have indicated that TO exhibits anti-tumor properties, but its mechanism remains to be elucidated. In this study, we investigated the effect of TO on the cytotoxicity and production of cytokines in human hepatoma cell line, Hep G2. Our results show that TO decreased the cell viability by 26%, and significantly increased the tumor necrosis factor (TNF)-alpha and interleukin (IL)-1alpha production compared with media control (about 1.6-fold for TNF-alpha, and 2.4-fold for IL-1alpha, P < 0.05). Also, TO strongly induced apoptosis of Hep G2 cells as determined by flow cytometry. Increased amounts of TNF-alpha and IL-1alpha contributed to TO-induced apoptosis. Anti-TNF-alpha and IL-1alpha antibodies almost abolished it. These results suggest that TO induces cytotoxicity through TNF-alpha and IL-1alpha secretion in Hep G2 cells.

Characterization of pancreatic lesions from MT-tgf alpha, Ela-myc and MT-tgf alpha/Ela-myc single and double transgenic mice.

Science.gov (United States)

Liao, Dezhong Joshua; Wang, Yong; Wu, Jiusheng; Adsay, Nazmi Volkan; Grignon, David; Khanani, Fayyaz; Sarkar, Fazlul H

2006-07-05

In order to identify good animal models for investigating therapeutic and preventive strategies for pancreatic cancer, we analyzed pancreatic lesions from several transgenic models and made a series of novel findings. Female MT-tgf alpha mice of the MT100 line developed pancreatic proliferation, acinar-ductal metaplasia, multilocular cystic neoplasms, ductal adenocarcinomas and prominent fibrosis, while the lesions in males were less severe. MT-tgf alpha-ES transgenic lines of both sexes developed slowly progressing lesions that were similar to what was seen in MT100 males. In both MT100 and MT-tgf alpha-ES lines, TGF alpha transgene was expressed mainly in proliferating ductal cells. Ela-myc transgenic mice with a mixed C57BL/6, SJL and FVB genetic background developed pancreatic tumors at 2-7 months of age, and half of the tumors were ductal adenocarcinomas, similar to what was reported originally by Sandgren et al 1. However, in 20% of the mice, the tumors metastasized to the liver. MT100/Ela-myc and MT-tgf alpha-ES/Ela-myc double transgenic mice developed not only acinar carcinomas and mixed carcinomas as previously reported but also various ductal-originated lesions, including multilocular cystic neoplasms and ductal adenocarcinomas. The double transgenic tumors were more malignant and metastasized to the liver at a higher frequency (33%) compared with the Ela-myc tumors. Sequencing of the coding region of p16ink4, k-ras and Rb cDNA in small numbers of pancreatic tumors did not identify mutations. The short latency for tumor development, the variety of tumor morphology and the liver metastases seen in Ela-myc and MT-tgf alpha/Ela-myc mice make these animals good models for investigating new therapeutic and preventive strategies for pancreatic cancer.

Chromospheric Lyman-alpha spectro-polarimeter (CLASP)

Science.gov (United States)

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

2012-09-01

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

Recombination epoch revisited

International Nuclear Information System (INIS)

Krolik, J.H.

1989-01-01

Previous studies of cosmological recombination have shown that this process produces as a by-product a highly superthermal population of Ly-alpha photons which retard completion of recombination. Cosmological redshifting was thought to determine the frequency distribution of the photons, while two-photon decay of hydrogen's 2s state was thought to control their numbers. It is shown here that frequency diffusion due to photon scattering dominate the cosmological redshift in the frequency range near line center which fixes the ratio of ground state to excited state population, while incoherent scattering into the far-red damping wing effectively destroys Ly-alpha photons as a rate which is competitive with two-photon decay. The former effect tends to hold back recombination, while the latter tends to accelerate it; the net results depends on cosmological parameters, particularly the combination Omega(b) h/sq rt (2q0), where Omega(b) is the fraction of the critical density provided by baryons. 18 references

Assessment of variations in taxonomic diversity, forest structure, and aboveground biomass using remote sensing along an altitudinal gradient in tropical montane forest of Costa Rica

Science.gov (United States)

Robinson, C. M.; Saatchi, S. S.; Clark, D.; Fricker, G. A.; Wolf, J.; Gillespie, T. W.; Rovzar, C. M.; Andelman, S.

2012-12-01

This research sought to understand how alpha and beta diversity of plants vary and relate to the three-dimensional vegetation structure and aboveground biomass along environmental gradients in the tropical montane forests of Braulio Carrillo National Park in Costa Rica. There is growing evidence that ecosystem structure plays an important role in defining patterns of species diversity and along with abiotic factors (climate and edaphic) control the phenotypic and functional variations across landscapes. It is well documented that strong subdivisions at local and regional scales are found mainly on geologic or climate gradients. These general determinants of biodiversity are best demonstrated in regions with natural gradients such as tropical montane forests. Altitudinal gradients provide a landscape scale changes through variations in topography, climate, and edaphic conditions on which we tested several theoretical and biological hypotheses regarding drivers of biodiversity. The study was performed by using forest inventory and botanical data from nine 1-ha plots ranging from 100 m to 2800 m above sea level and remote sensing data from airborne lidar and radar sensors to quantify variations in forest structure. In this study we report on the effectiveness of relating patterns of tree taxonomic alpha diversity to three-dimensional structure of a tropical montane forest using lidar and radar observations of forest structure and biomass. We assessed alpha and beta diversity at the species, genus, and family levels utilizing datasets provided by the Terrestrial Ecology Assessment and Monitoring (TEAM) Network. Through the comparison to active remote sensing imagery, our results show that there is a strong relationship between forest 3D-structure, and alpha and beta diversity controlled by variations in abiotic factors along the altitudinal gradient. Using spatial analysis with the aid of remote sensing data, we find distinct patterns along the environmental gradients

Rational design of a fibroblast growth factor 21-based clinical candidate, LY2405319.

Directory of Open Access Journals (Sweden)

Alexei Kharitonenkov

Full Text Available Fibroblast growth factor 21 is a novel hormonal regulator with the potential to treat a broad variety of metabolic abnormalities, such as type 2 diabetes, obesity, hepatic steatosis, and cardiovascular disease. Human recombinant wild type FGF21 (FGF21 has been shown to ameliorate metabolic disorders in rodents and non-human primates. However, development of FGF21 as a drug is challenging and requires re-engineering of its amino acid sequence to improve protein expression and formulation stability. Here we report the design and characterization of a novel FGF21 variant, LY2405319. To enable the development of a potential drug product with a once-daily dosing profile, in a preserved, multi-use formulation, an additional disulfide bond was introduced in FGF21 through Leu118Cys and Ala134Cys mutations. FGF21 was further optimized by deleting the four N-terminal amino acids, His-Pro-Ile-Pro (HPIP, which was subject to proteolytic cleavage. In addition, to eliminate an O-linked glycosylation site in yeast a Ser167Ala mutation was introduced, thus allowing large-scale, homogenous protein production in Pichia pastoris. Altogether re-engineering of FGF21 led to significant improvements in its biopharmaceutical properties. The impact of these changes was assessed in a panel of in vitro and in vivo assays, which confirmed that biological properties of LY2405319 were essentially identical to FGF21. Specifically, subcutaneous administration of LY2405319 in ob/ob and diet-induced obese (DIO mice over 7-14 days resulted in a 25-50% lowering of plasma glucose coupled with a 10-30% reduction in body weight. Thus, LY2405319 exhibited all the biopharmaceutical and biological properties required for initiation of a clinical program designed to test the hypothesis that administration of exogenous FGF21 would result in effects on disease-related metabolic parameters in humans.

A Comparitive Assessement of Cytokine Expression in Human-Derived Cell Lines Exposed to Alpha Particles and X-Rays

Directory of Open Access Journals (Sweden)

Vinita Chauhan

2012-01-01

Full Text Available Alpha- (α- particle radiation exposure has been linked to the development of lung cancer and has been identified as a radiation type likely to be employed in radiological dispersal devices. Currently, there exists a knowledge gap concerning cytokine modulations associated with exposure to α-particles. Bio-plex technology was employed to investigate changes in proinflammatory cytokines in two human-derived cell lines. Cells were irradiated at a dose of 1.5 Gy to either α-particles or X-rays at equivalent dose rates. The two cell lines exhibited a unique pattern of cytokine expression and the response varied with radiation type. Of the 27 cytokines assessed, only vascular endothelin growth factor (VEGF was observed to be modulated in both cell lines solely after α-particle exposure, and the expression of VEGF was shown to be dose responsive. These results suggest that certain proinflammatory cytokines may be involved in the biological effects related to α- particle exposure and the responses are cell type and radiation type specific.

Anticonvulsant actions of LY 367385 ((+)-2-methyl-4-carboxyphenylglycine) and AIDA ((RS)-1-aminoindan-1,5-dicarboxylic acid).

Science.gov (United States)

Chapman, A G; Yip, P K; Yap, J S; Quinn, L P; Tang, E; Harris, J R; Meldrum, B S

1999-02-26

We have studied the effects in three rodent models of generalised convulsive or absence epilepsy of two antagonists of group I metabotropic glutamate receptors that are selective for the mGlu1 receptor. LY 367385 ((+)-2-methyl-4-carboxyphenylglycine) and AIDA ((RS)-1-aminoindan-1,5-dicarboxylic acid) have been administered intracerebroventricularly (i.c.v.) to DBA/2 mice and lethargic mice (lh/lh), and focally into the inferior colliculus of genetically epilepsy prone rats (GEPR). In DBA/2 mice both compounds produce a rapid, transient suppression of sound-induced clonic seizures (LY 367385: ED50 = 12 nmol, i.c.v., 5 min; AIDA: ED50 = 79 nmol, i.c.v., 15 min). In lethargic mice both compounds significantly reduce the incidence of spontaneous spike and wave discharges on the electroencephalogram, from 150 min after the administration of AIDA, 500 nmol, i.c.v., and from 30 to >150 min after the administration of LY 367385, 250 nmol, i.c.v. LY 367385, 50 nmol, suppresses spontaneous spike and wave discharges from 30 to 60 min. In genetically epilepsy prone rats both compounds reduce sound-induced clonic seizures. LY 367385, 160 nmol bilaterally, fully suppresses clonic seizures after 2-4 h. AIDA is fully effective 30 min after 100 nmol bilaterally. It is concluded that antagonists of mGlu1 receptors are potential anticonvulsant agents and that activation of mGlu1 receptors probably contributes to a variety of epileptic syndromes.

Novel LY Converter Topologies for High Gain Transfer Ratio - A New Breed of XY Family

DEFF Research Database (Denmark)

Bhaskar, M.S.; Padmanaban, S.; Kulkarni, R.

2016-01-01

gain and minimum internal resistance; such as a photovoltaic MLI system, high voltage applications and electrical drives. The conspicuous features of proposed LY converter topologies are i) Single power control switch ii) Single Input source iii) Inverting output voltage iv) Transformer-less converter...... topologies v) High inverting voltage gain with moderate duty ratio vi) Less number of power devices and components. The proposed topologies have minimum internal resistance and its effect on voltage gain of LY converter is also discussed in detail. The simulation results are presented and the result...

Waste management capabilities for alpha bearing wastes at the Los Alamos Scientific Laboratory

International Nuclear Information System (INIS)

Keenan, T.K.

1977-01-01

Waste Management activities at the Los Alamos Scientific Laboratory (LASL) involve a broad range of effort. There are requirements for daily processing of both liquid and solid radioactive and chemical wastes using a variety of technical operations. Approximately 4.5 x 10 7 l/y of liquids and 9 x 10 3 m 3 /y of solids are processed by the Waste Management Group of the LASL. In addition, a vigorous program of research, development, and demonstration studies leading to improved methods of waste treatment is also carried out within the same group. The current developmental studies involve incineration of transuranic-contaminated combustible wastes as well as other waste management aspects of alpha emitting transuranic (TRU) isotopes

Tumor cell alpha-N-acetylgalactosaminidase activity and its involvement in GcMAF-related macrophage activation.

Science.gov (United States)

Mohamad, Saharuddin B; Nagasawa, Hideko; Uto, Yoshihiro; Hori, Hitoshi

2002-05-01

Alpha-N-acetyl galactosaminidase (alpha-NaGalase) has been reported to accumulate in serum of cancer patients and be responsible for deglycosylation of Gc protein, which is a precursor of GcMAF-mediated macrophage activation cascade, finally leading to immunosuppression in advanced cancer patients. We studied the biochemical characterization of alpha-NaGalase from several human tumor cell lines. We also examined its effect on the potency of GcMAF to activate mouse peritoneal macrophage to produce superoxide in GcMAF-mediated macrophage activation cascade. The specific activity of alpha-NaGalases from human colon tumor cell line HCT116, human hepatoma cell line HepG2, and normal human liver cells (Chang liver cell line) were evaluated using two types of substrates; GalNAc-alpha-PNP (exo-type substrate) and Gal-beta-GalNAc-alpha-PNP (endo-type substrate). Tumor-derived alpha-NaGalase having higher activity than normal alpha-NaGalase, had higher substrate specificity to the exo-type substrate than to the endo-type substrate, and still maintained its activity at pH 7. GcMAF enhance superoxide production in mouse macrophage, and pre-treatment of GcMAF with tumor cell lysate reduce the activity. We conclude that tumor-derived alpha-NaGalase is different in biochemical characterization compared to normal alpha-NaGalase from normal Chang liver cells. In addition, tumor cell-derived alpha-NaGalase decreases the potency of GcMAF on macrophage activation.

Direct measurement of interstellar extinction toward young stars using atomic hydrogen Lyα absorption

Energy Technology Data Exchange (ETDEWEB)

McJunkin, Matthew; France, Kevin; Brown, Alexander [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Schneider, P. C. [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany); Herczeg, Gregory J. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Hillenbrand, Lynne [California Institute of Technology, Department of Astrophysics, MC105-24, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Schindhelm, Eric [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States); Edwards, Suzan, E-mail: matthew.mcjunkin@colorado.edu [Five College Astronomy Department, Smith College, Northampton, MA 01063 (United States)

2014-01-10

Interstellar reddening corrections are necessary to reconstruct the intrinsic spectral energy distributions (SEDs) of accreting protostellar systems. The stellar SED determines the heating and chemical processes that can occur in circumstellar disks. Measurement of neutral hydrogen absorption against broad Lyα emission profiles in young stars can be used to obtain the total H I column density (N(H I)) along the line of sight. We measure N(H I) with new and archival ultraviolet observations from the Hubble Space Telescope (HST) of 31 classical T Tauri and Herbig Ae/Be stars. The H I column densities range from log{sub 10}(N(H I)) ≈19.6-21.1, with corresponding visual extinctions of A{sub V} =0.02-0.72 mag, assuming an R{sub V} of 3.1. We find that the majority of the H I absorption along the line of sight likely comes from interstellar rather than circumstellar material. Extinctions derived from new HST blue-optical spectral analyses, previous IR and optical measurements, and new X-ray column densities on average overestimate the interstellar extinction toward young stars compared to the N(H I) values by ∼0.6 mag. We discuss possible explanations for this discrepancy in the context of a protoplanetary disk geometry.

MicroRNA Expression Profiling by Bead Array Technology in Human Tumor Cell Lines Treated with Interferon-Alpha-2a

Directory of Open Access Journals (Sweden)

Siegrist Fredy

2009-01-01

Full Text Available Abstract MicroRNAs are positive and negative regulators of eukaryotic gene expression that modulate transcript abundance by specific binding to sequence motifs located prevalently in the 3' untranslated regions of target messenger RNAs (mRNA. Interferon-alpha-2a (IFNα induces a large set of protein coding genes mediating antiproliferative and antiviral responses. Here we use a global microarray-based microRNA detection platform to identify genes that are induced by IFNα in hepatoma- or melanoma-derived human tumor cell lines. Despite the enormous differences in expression levels between these models, we were able to identify microRNAs that are upregulated by IFNα in both lines suggesting the possibility that interferon-regulated microRNAs are involved in the transcriptional repression of mRNA relevant to cytokine responses.

Chronic treatment with LY341495 decreases 5-HT2A receptor binding and hallucinogenic effects of LSD in mice

Science.gov (United States)

Moreno, José L.; Holloway, Terrell; Rayannavar, Vinayak; Sealfon, Stuart C.; González-Maeso, Javier

2013-01-01

Hallucinogenic drugs, such as lysergic acid diethylamide (LSD), mescaline and psilocybin, alter perception and cognitive processes. All hallucinogenic drugs have in common a high affinity for the serotonin 5-HT2A receptor. Metabotropic glutamate 2/3 (mGlu2/3) receptor ligands show efficacy in modulating the cellular and behavioral responses induced by hallucinogenic drugs. Here, we explored the effect of chronic treatment with the mGlu2/3 receptor antagonist 2S-2-amino-2-(1S,2S-2-carboxycyclopropan-1-yl)-3-(xanth-9-yl)-propionic acid (LY341495) on the hallucinogenic-like effects induced by LSD (0.24 mg/kg). Mice were chronically (21 days) treated with LY341495 (1.5 mg/kg), or vehicle, and experiments were carried out one day after the last injection. Chronic treatment with LY341495 down-regulated [3H]ketanserin binding in somatosensory cortex of wild-type, but not mGlu2 knockout (KO), mice. Head-twitch behavior, and expression of c-fos, egr-1 and egr-2, which are responses induced by hallucinogenic 5-HT2A agonists, were found to be significantly decreased by chronic treatment with LY341495. These findings suggest that repeated blockade of the mGlu2 receptor by LY341495 results in reduced 5-HT2A receptor-dependent hallucinogenic effects of LSD. PMID:23333599

Chronic treatment with LY341495 decreases 5-HT(2A) receptor binding and hallucinogenic effects of LSD in mice.

Science.gov (United States)

Moreno, José L; Holloway, Terrell; Rayannavar, Vinayak; Sealfon, Stuart C; González-Maeso, Javier

2013-03-01

Hallucinogenic drugs, such as lysergic acid diethylamide (LSD), mescaline and psilocybin, alter perception and cognitive processes. All hallucinogenic drugs have in common a high affinity for the serotonin 5-HT(2A) receptor. Metabotropic glutamate 2/3 (mGlu2/3) receptor ligands show efficacy in modulating the cellular and behavioral responses induced by hallucinogenic drugs. Here, we explored the effect of chronic treatment with the mGlu2/3 receptor antagonist 2S-2-amino-2-(1S,2S-2-carboxycyclopropan-1-yl)-3-(xanth-9-yl)-propionic acid (LY341495) on the hallucinogenic-like effects induced by LSD (0.24mg/kg). Mice were chronically (21 days) treated with LY341495 (1.5mg/kg), or vehicle, and experiments were carried out one day after the last injection. Chronic treatment with LY341495 down-regulated [(3)H]ketanserin binding in somatosensory cortex of wild-type, but not mGlu2 knockout (KO), mice. Head-twitch behavior, and expression of c-fos, egr-1 and egr-2, which are responses induced by hallucinogenic 5-HT(2A) agonists, were found to be significantly decreased by chronic treatment with LY341495. These findings suggest that repeated blockade of the mGlu2 receptor by LY341495 results in reduced 5-HT(2A) receptor-dependent hallucinogenic effects of LSD. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Unintended changes in protein expression revealed by proteomic analysis of seeds from transgenic pea expressing a bean alpha-amylase inhibitor gene.

Science.gov (United States)

Chen, Hancai; Bodulovic, Greg; Hall, Prudence J; Moore, Andy; Higgins, Thomas J V; Djordjevic, Michael A; Rolfe, Barry G

2009-09-01

Seeds of genetically modified (GM) peas (Pisum sativum L.) expressing the gene for alpha-amylase inhibitor-1 (alphaAI1) from the common bean (Phaseolus vulgaris L. cv. Tendergreen) exhibit resistance to the pea weevil (Bruchus pisorum). A proteomic analysis was carried out to compare seeds from GM pea lines expressing the bean alphaAI1 protein and the corresponding alphaAI1-free segregating lines and non-GM parental line to identify unintended alterations to the proteome of GM peas due to the introduction of the gene for alphaAI1. Proteomic analysis showed that in addition to the presence of alphaAI1, 33 other proteins were differentially accumulated in the alphaAI1-expressing GM lines compared with their non-GM parental line and these were grouped into five expression classes. Among these 33 proteins, only three were found to be associated with the expression of alphaAI1 in the GM pea lines. The accumulation of the remaining 30 proteins appears to be associated with Agrobacterium-mediated transformation events. Sixteen proteins were identified after MALDI-TOF-TOF analysis. About 56% of the identified proteins with altered accumulation in the GM pea were storage proteins including legumin, vicilin or convicilin, phaseolin, cupin and valosin-containing protein. Two proteins were uniquely expressed in the alphaAI1-expressing GM lines and one new protein was present in both the alphaAI1-expressing GM lines and their alphaAI1-free segregating lines, suggesting that both transgenesis and transformation events led to demonstrable changes in the proteomes of the GM lines tested.

Distinctive tropical forest variants have unique soil microbial communities, but not always low microbial diversity

Directory of Open Access Journals (Sweden)

Binu M Tripathi

2016-04-01

Full Text Available There has been little study of whether different variants of tropical rainforest have distinct soil microbial communities and levels of diversity. We compared bacterial and fungal community composition and diversity between primary mixed dipterocarp, secondary mixed dipterocarp, white sand heath, inland heath, and peat swamp forests in Brunei Darussalam, northwest Borneo by analyzing Illumina Miseq sequence data of 16S rRNA gene and ITS1 region. We hypothesized that white sand heath, inland heath and peat swamp forests would show lower microbial diversity and relatively distinct microbial communities (compared to MDF primary and secondary forests due to their distinctive environments. We found that soil properties together with bacterial and fungal communities varied significantly between forest types. Alpha and beta-diversity of bacteria was highest in secondary dipterocarp and white sand heath forests. Also, bacterial alpha diversity was strongly structured by pH, adding another instance of this widespread pattern in nature. The alpha diversity of fungi was equally high in all forest types except peat swamp forest, although fungal beta-diversity was highest in primary and secondary mixed dipterocarp forests. The relative abundance of ectomycorrhizal (EcM fungi varied significantly between forest types, with highest relative abundance observed in MDF primary forest. Overall, our results suggest that the soil bacterial and fungal communities in these forest types are to a certain extent predictable and structured by soil properties, but that diversity is not determined by how distinctive the conditions are. This contrasts with the diversity patterns seen in rainforest trees, where distinctive soil conditions have consistently lower tree diversity.

Radiosensitivity of Prostate Cancer Cell Lines for Irradiation from Beta Particle-emitting Radionuclide ¹⁷⁷Lu Compared to Alpha Particles and Gamma Rays.

Science.gov (United States)

Elgqvist, Jörgen; Timmermand, Oskar Vilhelmsson; Larsson, Erik; Strand, Sven-Erik

2016-01-01

The purpose of the present study was to investigate the radiosensitivity of the prostate cancer cell lines LNCaP, DU145, and PC3 when irradiated with beta particles emitted from (177)Lu, and to compare the effect with irradiation using alpha particles or gamma rays. Cells were irradiated with beta particles emitted from (177)Lu, alpha particles from (241)Am, or gamma rays from (137)Cs. A non-specific polyclonal antibody was labeled with (177)Lu and used to irradiate cells in suspension with beta particles. A previously described in-house developed alpha-particle irradiator based on a (241)Am source was used to irradiate cells with alpha particles. External gamma-ray irradiation was achieved using a standard (137)Cs irradiator. Cells were irradiated to absorbed doses equal to 0, 0.5, 1, 2, 4, 6, 8, or 10 Gy. The absorbed doses were calculated as mean absorbed doses. For evaluation of cell survival, the tetrazolium-based WST-1 assay was used. After irradiation, WST-1 was added to the cell solutions, incubated, and then measured for level of absorbance at 450 nm, indicating the live and viable cells. LNCaP, DU145, and PC3 cell lines all had similar patterns of survival for the different radiation types. No significant difference in surviving fractions were observed between cells treated with beta-particle and gamma-ray irradiation, represented for example by the surviving fraction values (mean±SD) at 2, 6, and 10 Gy (SF2, SF6, and SF10) for DU145 after beta-particle irradiation: 0.700±0.090, 0.186±0.050 and 0.056±0.010, respectively. A strong radiosensitivity to alpha particles was observed, with SF2 values of 0.048±0.008, 0.018±0.006 and 0.015±0.005 for LNCaP, DU145, and PC3, respectively. The surviving fractions after irradiation using beta particles or gamma rays did not differ significantly at the absorbed dose levels and dose rates used. Irradiation using alpha particles led to a high level of cell killing. The results show that the beta-particle emitter

SPECTROSCOPIC CONFIRMATION OF z {approx} 7 LYMAN BREAK GALAXIES: PROBING THE EARLIEST GALAXIES AND THE EPOCH OF REIONIZATION

Energy Technology Data Exchange (ETDEWEB)

Pentericci, L.; Fontana, A.; Castellano, M.; Grazian, A.; Boutsia, K.; Giallongo, E.; Maiolino, R.; Paris, D.; Santini, P. [INAF Osservatorio Astronomico di Roma, Via Frascati 33,00040 Monteporzio (Italy); Vanzella, E.; Cristiani, S. [INAF Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34131 Trieste (Italy); Dijkstra, M. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching (Germany); Dickinson, M. [National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726 (United States); Giavalisco, M. [Department of Astronomy, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Moorwood, A., E-mail: laura.pentericci@oa-roma.inaf.it [European Southern Observatory, Karl-Schwarzschild Strasse, 85748 Garching (Germany)

2011-12-20

We present the final results from our ultra-deep spectroscopic campaign with FORS2 at the ESO Very Large Telescope (VLT) for the confirmation of z {approx_equal} 7 'z-band dropout' candidates selected from our VLT/Hawk-I imaging survey over three independent fields. In particular, we report on two newly discovered galaxies at redshift {approx}6.7 in the New Technology Telescope Deep Field. Both galaxies show an Ly{alpha} emission line with rest-frame equivalent widths (EWs) of the order of 15-20 A and luminosities of (2-4) Multiplication-Sign 10{sup 42} erg s{sup -1}. We also present the results of ultra-deep observations of a sample of i-dropout galaxies, from which we set a solid upper limit on the fraction of interlopers. Out of the 20 z-dropouts observed we confirm 5 galaxies at 6.6 < z < 7.1. This is systematically below the expectations drawn on the basis of lower redshift observations: in particular, there is a significant lack of objects with intermediate Ly{alpha} EWs (between 20 and 55 A). We conclude that the observed trend for the rising fraction of Ly{alpha} emission in Lyman break galaxies from z {approx} 3 to z {approx} 6 is most probably reversed from z {approx} 6 to z {approx} 7. Explaining the observed rapid change in the Ly{alpha} emitter fraction among the dropout population with reionization requires a fast evolution of the neutral fraction of hydrogen in the universe. Assuming that the universe is completely ionized at z = 6 and adopting a set of semi-analytical models, we find that our data require a change of the neutral hydrogen fraction of the order of {Delta}{chi}{sub H{sub i}}{approx}0.6 in a time {Delta}z {approx} 1, provided that the escape fraction does not increase dramatically over the same redshift interval.

Study of Opacity Effects on Emission Lines at EXTRAP T2R RFP

Science.gov (United States)

Stancalie, Viorica; Rachlew, Elisabeth

We have investigated the influence of opacity on hydrogen (H-α and Ly-β) and Li-like oxygen emission lines from the EXTRAP T2R reversed field pinch. We used the Atomic Data Analysis System (AzDAS) based on the escape factor approximation for radiative transfer to calculate metastable and excited population densities via a collisional-radiative model. Population escape factor, emergent escape factor and modified line profiles are plotted vs. optical depth. The simulated emission line ratios in the density/temperature plane are in good agreement with experimental data for electron density and temperature measurements.

The Cryo-Thermochromatographic Separator (CTS) A new rapid separation and alpha-detection system for on-line chemical studies of highly volatile osmium and hassium (Z=108) tetroxides

CERN Document Server

Kirbach, U W; Gregorich, K E; Lee, D M; Ninov, V; Omtvedt, J P; Patin, J B; Seward, N K; Strellis, D A; Sudowe, R; Türler, A; Wilk, P A; Zielinski, P M; Hoffman, D C; Nitsche, H

2002-01-01

The Cryo-Thermochromatographic Separator (CTS) was designed and constructed for rapid, continuous on-line separation and simultaneous detection of highly volatile compounds of short-lived alpha-decaying isotopes of osmium and hassium (Hs, Z=108). A flowing carrier gas containing the volatile species is passed through a channel formed by two facing rows of 32 alpha-particle detectors, cooled to form a temperature gradient extending from 247 K at the channel entrance down to 176 K at the exit. The volatile species adsorb onto the SiO sub 2 -coated detector surfaces at a characteristic deposition temperature and are identified by their observed alpha-decay energies. The CTS was tested on-line with OsO sub 4 prepared from sup 1 sup 6 sup 9 sup - sup 1 sup 7 sup 3 Os isotopes produced in sup 1 sup 1 sup 8 sup , sup 1 sup 2 sup 0 Sn( sup 5 sup 6 Fe, 3,4,5n) reactions. An adsorption enthalpy for OsO sub 4 of -40.2+-1.5 kJ/mol on SiO sub 2 was deduced by comparing the measured deposition distribution with Monte Carlo...

Discovery of Scattering Polarization in the Hydrogen Ly alpha Line of the Solar Disk Radiation

Czech Academy of Sciences Publication Activity Database

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

2017-01-01

Roč. 839, č. 1 (2017), L10/1-L10/6 ISSN 2041-8205 Institutional support: RVO:67985815 Keywords : vacuum-ultraviolet spectropolarimeter * transition region * chromosphere Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 5.522, year: 2016

Wavelet Space-Scale-Decomposition Analysis of QSO's Ly$\\alpha$ Absorption Lines: Spectrum of Density Perturbations

OpenAIRE

Pando, Jesus; Fang, Li-Zhi

1995-01-01

A method for measuring the spectrum of a density field by a discrete wavelet space-scale decomposition (SSD) has been studied. We show how the power spectrum can effectively be described by the father function coefficients (FFC) of the wavelet SSD. We demonstrate that the features of the spectrum, such as the magnitude, the index of a power law, and the typical scales, can be determined with high precision by the FFC reconstructed spectrum. This method does not require the mean density, which...

EUFODOS: European Forest Downstream Services - Improved Information on Forest Structure and Damage

Science.gov (United States)

Hirschmugl, M.; Gallaun, H.; Wack, R.; Granica, K.; Schardt, M.

2013-05-01

Forests play a key role in the European economy and environment. This role incorporates ecological functions which can be affected by the occurrence of insect infestations, forest fire, heavy snowfall or windfall events. Local or Regional Authorities (LRAs) thus require detailed information on the degradation status of their forests to be able to take appropriate measures for their forest management plans. In the EUFODOS project, state-of-the-art satellite and laser scanning technologies are used to provide forest authorities with cost-effective and comprehensive information on forest structure and damage. One of the six test sites is located in the Austrian province of Styria where regional forest authorities have expressed a strong need for detailed forest parameters in protective forest. As airborne laser-scanning data is available, it will be utilized to derive detailed forest parameters such as the upper forest border line, tree height, growth classes, forest density, vertical structure or volume. At the current project status, the results of (i) the forest border line, (ii) the segmentation of forest stands and (iii) the tree top detection are available and presented including accuracy assessment and interim results are shown for timber volume estimations. The final results show that the forest border can be mapped operationally with an overall accuracy of almost 99% from LiDAR data. For the segmentation of forest stands, a comparison of the automatically derived result with visual-manual delineation showed in general a more detailed segmentation result, but for all visual-manual segments a congruence of 87% within a 4 m buffer. Tree top detections were compared to stem numbers estimated based on angle-count samplings in a field campaign, which led to a correlation coefficient (R) of 0.79.

alpha-MSH and its receptors in regulation of tumor necrosis factor-alpha production by human monocyte/macrophages.

Science.gov (United States)

Taherzadeh, S; Sharma, S; Chhajlani, V; Gantz, I; Rajora, N; Demitri, M T; Kelly, L; Zhao, H; Ichiyama, T; Catania, A; Lipton, J M

1999-05-01

The hypothesis that macrophages contain an autocrine circuit based on melanocortin [ACTH and alpha-melanocyte-stimulating hormone (alpha-MSH)] peptides has major implications for neuroimmunomodulation research and inflammation therapy. To test this hypothesis, cells of the THP-1 human monocyte/macrophage line were stimulated with lipopolysaccharide (LPS) in the presence and absence of alpha-MSH. The inflammatory cytokine tumor necrosis factor (TNF)-alpha was inhibited in relation to alpha-MSH concentration. Similar inhibitory effects on TNF-alpha were observed with ACTH peptides that contain the alpha-MSH amino acid sequence and act on melanocortin receptors. Nuclease protection assays indicated that expression of the human melanocortin-1 receptor subtype (hMC-1R) occurs in THP-1 cells; Southern blots of RT-PCR product revealed that additional subtypes, hMC-3R and hMC-5R, also occur. Incubation of resting macrophages with antibody to hMC-1R increased TNF-alpha concentration; the antibody also markedly reduced the inhibitory influence of alpha-MSH on TNF-alpha in macrophages treated with LPS. These results in cells known to produce alpha-MSH at rest and to increase secretion of the peptide when challenged are consistent with an endogenous regulatory circuit based on melanocortin peptides and their receptors. Targeting of this neuroimmunomodulatory circuit in inflammatory diseases in which myelomonocytic cells are prominent should be beneficial.

Self-reported adherence and biomarker levels of CoQ10 and alpha-tocopherol

Directory of Open Access Journals (Sweden)

Vitolins MZ

2018-04-01

Full Text Available Mara Z Vitolins,1 L Douglas Case,1 Stephen R Rapp,2 Mark O Lively,3 Edward G Shaw,4 Michelle J Naughton,5 Jeffrey Giguere,6 Glenn J Lesser7 1Division of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, NC, USA; 2Department of Psychiatry and Behavioral Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA; 3Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC, USA; 4Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA; 5Department of Internal Medicine, The Ohio State University, Columbus, OH, USA; 6Greenville Community Oncology Research Program of the Carolinas, Greenville, SC, USA; 7Department of Internal Medicine-Hematology and Oncology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA Purpose: Women with breast cancer were randomized to receive coenzyme Q10 (CoQ10 plus Vitamin E or placebo in a clinical trial. The objective of this evaluation is to examine the association between participant self-reported adherence to the study supplements and changes in plasma biomarker levels.Patients and methods: Correlation coefficients quantified the association between changes in alpha-tocopherol and CoQ10 levels and the association between self-reported adherence and changes in biomarkers. Participants were categorized by self-reported adherence; Kruskal–Wallis tests compared changes in alpha-tocopherol and CoQ10 levels between self-reported adherence groups.Results: Women (N=155 provided baseline and post-treatment biomarkers; 147 completed at least one diary. While changes in alpha-tocopherol and CoQ10 levels were moderately correlated, correlations ranged from 0.40 to 0.48, association between self-reported adherence and plasma alpha-tocopherol or CoQ10 levels was weak; correlations ranged from 0.10 to 0.29 at weeks 8, 16, and 24. Some participants with high self-reported adherence actually

Dose study of the multikinase inhibitor, LY2457546, in patients with relapsed acute myeloid leukemia to assess safety, pharmacokinetics, and pharmacodynamics

International Nuclear Information System (INIS)

Wacheck, Volker; Lahn, Michael; Dickinson, Gemma; Füreder, Wolfgang; Meyer, Renata; Herndlhofer, Susanne; Füreder, Thorsten; Dorfner, Georg; Pillay, Sada; André, Valérie; Burkholder, Timothy P; Akunda, Jacqueline K; Flye-Blakemore, Leann; Van Bockstaele, Dirk; Schlenk, Richard F; Sperr, Wolfgang R; Valent, Peter

2011-01-01

Acute myeloid leukemia (AML) is a life-threatening malignancy with limited treatment options in chemotherapy-refractory patients. A first-in-human dose study was designed to investigate a safe and biologically effective dose range for LY2457546, a novel multikinase inhibitor, in patients with relapsed AML. In this nonrandomized, open-label, dose escalation Phase I study, LY2457546 was administered orally once a day. Safety, pharmacokinetics, changes in phosphorylation of target kinases in AML blasts, and risk of drug–drug interactions (DDI) were assessed. Five patients were treated at the starting and predicted minimal biologically effective dose of 50 mg/day. The most commonly observed adverse events were febrile neutropenia, epistaxis, petechiae, and headache. The majority of adverse events (81%) were Grade 1 or 2. One patient had generalized muscle weakness (Grade 3), which was deemed to be a dose-limiting toxicity. Notably, the pharmacokinetic profile of LY2457546 showed virtually no elimination of LY2457546 within 24 hours, and thus prevented further dose escalation. No significant DDI were observed. Ex vivo flow cytometry studies showed downregulation of the phosphoproteins, pcKIT, pFLT3, and pS6, in AML blasts after LY2457546 administration. No medically relevant responses were observed in the five treated patients. No biologically effective dose could be established for LY2457546 in chemotherapy-resistant AML patients. Lack of drug clearance prevented safe dose escalation, and the study was terminated early. Future efforts should be made to develop derivatives with a more favorable pharmacokinetic profile

T cell antigen receptor expression by subsets of Ly-2-L3T4- (CD8-CD4-) thymocytes

DEFF Research Database (Denmark)

Wilson, A; Ewing, T; Owens, T

1988-01-01

. No positive cells were detected among Ly-2-L3T4- thymocytes from V beta 8-negative SJL mice. In contrast to the adult thymus, Ly-2-L3T4- cells from embryonic CBA thymus lacked F23.1-positive cells. Subsets of adult CBA Ly-2-L3T4- thymocytes were separated to determine which expressed V beta 8. The major...... B2A2-M1/69- and Pgp-1+ all included strongly F23.1-positive cells. A minor subset, negative for most markers except Pgp-1 and presumed on the basis of this phenotype and some reconstitution studies to include the earliest intrathymic precursors, contained 28% F23.1-positive cells. However, no F.23...

Field production and functional evaluation of chloroplast-derived interferon-alpha2b.

Science.gov (United States)

Arlen, Philip A; Falconer, Regina; Cherukumilli, Sri; Cole, Amy; Cole, Alexander M; Oishi, Karen K; Daniell, Henry

2007-07-01

Type I interferons (IFNs) inhibit viral replication and cell growth and enhance the immune response, and therefore have many clinical applications. IFN-alpha2b ranks third in world market use for a biopharmaceutical, behind only insulin and erythropoietin. The average annual cost of IFN-alpha2b for the treatment of hepatitis C infection is $26,000, and is therefore unavailable to the majority of patients in developing countries. Therefore, we expressed IFN-alpha2b in tobacco chloroplasts, and transgenic lines were grown in the field after obtaining United States Department of Agriculture Animal and Plant Health Inspection Service (USDA-APHIS) approval. Stable, site-specific integration of transgenes into chloroplast genomes and homoplasmy through several generations were confirmed. IFN-alpha2b levels reached up to 20% of total soluble protein, or 3 mg per gram of leaf (fresh weight). Transgenic IFN-alpha2b had similar in vitro biological activity to commercially produced PEG-Introntrade mark when tested for its ability to protect cells against cytopathic viral replication in the vesicular stomatitis virus cytopathic effect (VSV CPE) assay and to inhibit early-stage human immunodeficiency virus (HIV) infection. The antitumour and immunomodulating properties of IFN-alpha2b were also seen in vivo. Chloroplast-derived IFN-alpha2b increased the expression of major histocompatibility complex class I (MHC I) on splenocytes and the total number of natural killer (NK) cells. Finally, IFN-alpha2b purified from chloroplast transgenic lines (cpIFN-alpha2b) protected mice from a highly metastatic tumour line. This demonstration of high levels of expression of IFN-alpha2b, transgene containment and biological activity akin to that of commercial preparations of IFN-alpha2b facilitated the first field production of a plant-derived human blood protein, a critical step towards human clinical trials and commercialization.

78 FR 37781 - Forest Resource Coordinating Committee; Meeting

Science.gov (United States)

2013-06-24

... DEPARTMENT OF AGRICULTURE Forest Service Forest Resource Coordinating Committee; Meeting AGENCY: Forest Service, USDA. ACTION: Notice of meeting; Correction. SUMMARY: The Forest Service published a... teleconference line. FOR FURTHER INFORMATION CONTACT: Maya Solomon, Forest Resource Coordinating Committee...

EUFODOS: European Forest Downstream Services – Improved Information on Forest Structure and Damage

Directory of Open Access Journals (Sweden)

M. Hirschmugl

2013-05-01

Full Text Available Forests play a key role in the European economy and environment. This role incorporates ecological functions which can be affected by the occurrence of insect infestations, forest fire, heavy snowfall or windfall events. Local or Regional Authorities (LRAs thus require detailed information on the degradation status of their forests to be able to take appropriate measures for their forest management plans. In the EUFODOS project, state-of-the-art satellite and laser scanning technologies are used to provide forest authorities with cost-effective and comprehensive information on forest structure and damage. One of the six test sites is located in the Austrian province of Styria where regional forest authorities have expressed a strong need for detailed forest parameters in protective forest. As airborne laser-scanning data is available, it will be utilized to derive detailed forest parameters such as the upper forest border line, tree height, growth classes, forest density, vertical structure or volume. At the current project status, the results of (i the forest border line, (ii the segmentation of forest stands and (iii the tree top detection are available and presented including accuracy assessment and interim results are shown for timber volume estimations. The final results show that the forest border can be mapped operationally with an overall accuracy of almost 99% from LiDAR data. For the segmentation of forest stands, a comparison of the automatically derived result with visual-manual delineation showed in general a more detailed segmentation result, but for all visual-manual segments a congruence of 87% within a 4 m buffer. Tree top detections were compared to stem numbers estimated based on angle-count samplings in a field campaign, which led to a correlation coefficient (R of 0.79.

Combined cytotoxic effects of tumor necrosis factor-alpha with various cytotoxic agents in tumor cell lines that are drug resistant due to mutated p53

NARCIS (Netherlands)

Sleijfer, S; Le, T. K. P.; de Jong, S.; Timmer-Bosscha, H; Withoff, S; Mulder, NH

Several studies suggest that tumor necrosis factor-alpha (TNF) is able to overcome drug resistance in tumors. Whether TNF is able to do so in tumor cell lines that are drug resistant due to a mutation in the tumor suppressor gene p53 is unclear. Therefore, we studied the in vitro cytotoxic effects

Analysis of alpha spectrum instrumental errors accounting for the low energy part of semiconductor detector response function

International Nuclear Information System (INIS)

Gurbich, A.F.

1981-01-01

A technique for processing of instrumental spectrum of charged particles permitting to take account of a low-energy part of spectrometer line shape, to improve accuracy and to estimate detection efficiency is stated on the example of 226 Ra alpha spectrum. The results obtained show that relative intensities of alpha lines within the limits of statistical errors coincide with the known values, line ''tails'' constituting to 3% of total area of the line. Taking account of ''the line tail'' results in shift of centers of peak gravity by 10-20 keV. So low-energy part of the alpha spectrometer line, which is usually not taken account during spectra processing, markedly affect the results [ru

Radiosensitivity of mesothelioma cell lines

Energy Technology Data Exchange (ETDEWEB)

Haekkinen, A.M. [Dept. of Oncology, Univ. Central Hospital, Helsinki (Finland); Laasonen, A. [Dept. of Pathology, Central Hospital of Etelae-Pohjanmaa, Seinaejoki (Finland); Linnainmaa, K. [Dept. of Industrial Hygiene and Toxicology, Inst. of Occupational Health, Helsinki (Finland); Mattson, K. [Dept. Pulmonary Medicine, Univ. Central Hospital, Helsinki (Finland); Pyrhoenen, S. [Dept. of Oncology, Univ. Central Hospital, Helsinki (Finland)

1996-10-01

The present study was carried out in order to examine the radiosensitivity of malignant pleural mesothelioma cell lines. Cell kinetics, radiation-induced delay of the cell cycle and DNA ploidy of the cell lines were also determined. For comparison an HeLa and a human foetal fibroblast cell line were simultaneously explored. Six previously cytogenetically and histologically characterized mesothelioma tumor cell lines were applied. A rapid tiazolyl blue microtiter (MTT) assay was used to analyze radiosensitivity and cell kinetics and DNA ploidy of the cultured cells were determined by flow cytometry. The survival fraction after a dose of 2 Gy (SF2), parameters {alpha} and {beta} of the linear quadratic model (LQ-model) and mean inactivation dose (D{sub MID}) were also estimated. The DNA index of four cell lines equaled 1.0 and two cell lines equaled 1.5 and 1.6. Different mesothelioma cell lines showed a great variation in radiosensitivity. Mean survival fraction after a radiation dose of 2 Gy (SF2) was 0.60 and ranged from 0.36 to 0.81 and mean {alpha} value was 0.26 (range 0.48-0.083). The SF2 of the most sensitive diploid mesothelioma cell line was 0.36: Less than that of the foetal fibroblast cell line (0.49). The survival fractions (0.81 and 0.74) of the two most resistant cell lines, which also were aneuploid, were equal to that of the HeLa cell line (0.78). The {alpha}/{beta} ratios of the most sensitive cell lines were almost an order of magnitude greater than those of the two most resistant cell lines. Radiation-induced delay of the most resistant aneuploid cell line was similar to that of HeLa cells but in the most sensitive (diploid cells) there was practically no entry into the G1 phase following the 2 Gy radiation dose during 36 h. (orig.).

A METALLICITY-SPIN TEMPERATURE RELATION IN DAMPED Lyα SYSTEMS

International Nuclear Information System (INIS)

Kanekar, Nissim; Smette, Alain; Briggs, Frank H.; Chengalur, Jayaram N.

2009-01-01

We report evidence for an anti-correlation between spin temperature T s and metallicity [Z/H], detected at 3.6σ significance in a sample of 26 damped Lyα absorbers (DLAs) at redshifts 0.09 s = (-0.68 ± 0.17) x [Z/H] + (2.13 ± 0.21) from a linear regression analysis. Our results indicate that the high T s values found in DLAs do not arise from differences between the optical and radio sightlines, but are likely to reflect the underlying gas temperature distribution. The trend between T s and [Z/H] can be explained by the larger number of radiation pathways for gas cooling in galaxies with high metal abundances, resulting in a high cold gas fraction, and hence, a low spin temperature. Conversely, low-metallicity galaxies have fewer cooling routes, yielding a larger warm gas fraction and a high T s . Most DLAs at z > 1.7 have low metallicities, [Z/H] s and [Z/H] is consistent with the presence of a mass-metallicity relation in DLAs, suggested by the tight correlation between DLA metallicity and the kinematic widths of metal lines. Most high-z DLAs are likely to arise in galaxies with low masses (M vir 10.5 M sun ), low metallicities ([Z/H] <-1), and low cold gas fractions.

Chromospheric LAyer SpectroPolarimeter (CLASP2)

Science.gov (United States)

Narukage, Noriyuki; Cirtain, Jonathan W.; Ishikawa, Ryoko; Trujillo-Bueno, Javier; De Pontieu, Bart; Kubo, Masahito; Ishikawa, Shinnosuke; Kano, Ryohei; Suematsu, Yoshinori; Yoshida, Masaki;

Biomodulation with sequential intravenous IFN-alpha2b and 5-fluorouracil as second-line treatment in patients with advanced colorectal cancer.

Science.gov (United States)

Pérez, J E; Lacava, J A; Domínguez, M E; Rodríguez, R; Barbieri, M R; Romero Acuña, L A; Romero Acuña, J M; Langhi, M J; Amato, S; Marrone, N; Ortiz, E H; Leone, B A; Vallejo, C T; Machiavelli, M R; Romero, A O

1998-08-01

A phase II trial was carried out by the Grupo Oncologico Cooperativo del Sur (G.O.C.S.) to assess the efficacy and toxicity of a biochemical modulation of 5-fluorouracil (5-FU) by i.v. pretreatment with interferon (IFN)-alpha2b in patients with advanced colorectal carcinoma refractory to previous therapy with 5-FU modulated by methotrexate (MTX) or leucovorin (LV) or both. Between January 1993 and October 1995, 34 patients were entered on the study. The treatment was IFN-alpha2b 5 x 10(6)/m2 IU in a 1-h i.v. infusion, followed immediately by 5-FU 600 mg/m2 i.v. bolus injection. Courses were repeated weekly until observation of progressive disease or severe toxicity. One patient could not be assessed for response. Objective regression was observed in 2 of 33 patients (6%, 95% confidence interval, 0%-14%). No patient achieved a complete response. Two patients had partial responses (6%). No change was recorded in 14 patients (41%), and progressive disease occurred in 17 (52%). The median time to treatment failure was 3 months, and the median survival was 5 months. Toxicity was within acceptable limits. The main side effects were mucositis and diarrhea. Four episodes of grade 2 stomatitis were observed, causing dosage modifications. The most frequent toxic effects attributable to IFN-alpha2b were mild fatigue and fever. In conclusion, second-line therapy with i.v. IFN-alpha2b preceding 5-FU has shown an interesting profile of activity in a patient population with clearly unfavorable characteristics. From this perspective, further appropriately designed studies are needed to identify the greatest potential of IFN-alpha2b as a modulator of 5-FU.

Trahv? Herned klassinurgas? Või hoopis ihunuhtlus? / Pilme, Lea; Kivistik, Ly; Sirgmets, Raili; Part, Aivar

Index Scriptorium Estoniae

2008-01-01

Suhtumisest koolijuhtidele trahvimisõiguse andmise ideesse vestlevad Rakvere Põhikooli direktor Lea Pilme, Uhtna Põhikooli direktor Ly Kivistik, Väike-Maarja Gümnaasiumi direktor Raili Sirgmets ja Rakvere Gümnaasiumi direktor Aivar Part

Changing Traditions and Village Development in Kalotaszentkirály

Directory of Open Access Journals (Sweden)

Wayne Kraft

2011-10-01

Full Text Available The continuity of village traditions depends on the stability and cohesion of village communities. Since the opening of Transylvania after the fall of Nicolae Ceauşescu, there has been a sort of revival of Hungarian village dance and music, on the one hand, but, on the longer term, the communities themselves are threatened by economic challenges and by consequent demographic changes. This essay is based on field research conducted in Kalotaszentkirály (Sincraiu from 1995 to 2010.

Absorption and disposition of LY127210, an orally effective hypotensive agent, in laboratory animals

International Nuclear Information System (INIS)

Turner, J.C.; White, J.F.; Sullivan, H.R.

1986-01-01

The disposition, pharmacokinetics, and metabolic fate of LY127210, 7,8-dimethoxy-(1H)-3-benzazepin-2-amine hydrochloride, have been studied in mice, rats, dogs and monkeys. Pharmacokinetic and bioavailability studies in dogs and monkeys showed it to be well absorbed orally with maximum plasma levels of drug obtained within 4 hr. Following administration of 14 C-LY127210, the plasma half-lives of parent and radiocarbon in rat were 11 hr and 45 hr (β-phase), respectively. In dogs and monkeys parent half-lives were 11 hr (β-phase) and 5.2 hr (monophasic) while half-lives of total radiocarbon were 145 hr (β-phase) and 299 hr (β-phase), respectively. Plasma concentrations of parent compound in rat, dog, and monkey following oral administration accounted for approximately 15% of circulating radiocarbon. Renal excretion was the major route of elimination. The major urinary species was LY127210; metabolic mechanisms included oxidative O-demethylation and deamination, aliphatic oxidation, and reduction. Radiocarbon tissue level studies in rat indicated wide distribution of drug and/or metabolites. Similar studies in monkeys indicated that the half-life of radiocarbon in tissues was equal to or greater than that in plasma and red blood cells. The long half-life of radiocarbon in blood was due to irreversible dose dependent binding of drug and/or metabolites to plasma albumin and to cellular hemoglobin

Consistent patterns of high alpha and low beta diversity in tropical parasitic and free-living protists.

Science.gov (United States)

Lentendu, Guillaume; Mahé, Frédéric; Bass, David; Rueckert, Sonja; Stoeck, Thorsten; Dunthorn, Micah

2018-05-30

Tropical animals and plants are known to have high alpha diversity within forests, but low beta diversity between forests. By contrast, it is unknown whether microbes inhabiting the same ecosystems exhibit similar biogeographic patterns. To evaluate the biogeographies of tropical protists, we used metabarcoding data of species sampled in the soils of three lowland Neotropical rainforests. Taxa-area and distance-decay relationships for three of the dominant protist taxa and their subtaxa were estimated at both the OTU and phylogenetic levels, with presence-absence and abundance-based measures. These estimates were compared to null models. High local alpha and low regional beta diversity patterns were consistently found for both the parasitic Apicomplexa and the largely free-living Cercozoa and Ciliophora. Similar to animals and plants, the protists showed spatial structures between forests at the OTU and phylogenetic levels, and only at the phylogenetic level within forests. These results suggest that the biogeographies of macro- and micro-organismal eukaryotes in lowland Neotropical rainforests are partially structured by the same general processes. However, and unlike the animals and plants, the protist OTUs did not exhibit spatial structures within forests, which hinders our ability to estimate the local and regional diversity of protists in tropical forests. © 2018 John Wiley & Sons Ltd.

TNF-{alpha} promotes human retinal pigment epithelial (RPE) cell migration by inducing matrix metallopeptidase 9 (MMP-9) expression through activation of Akt/mTORC1 signaling

Energy Technology Data Exchange (ETDEWEB)

Wang, Cheng-hu; Cao, Guo-Fan [The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029 (China); Jiang, Qin, E-mail: Jqin710@vip.sina.com [The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029 (China); Yao, Jin, E-mail: dryaojin@yahoo.com [The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029 (China)

2012-08-17

Highlights: Black-Right-Pointing-Pointer TNF-{alpha} induces MMP-9 expression and secretion to promote RPE cell migration. Black-Right-Pointing-Pointer MAPK activation is not critical for TNF-{alpha}-induced MMP-9 expression. Black-Right-Pointing-Pointer Akt and mTORC1 signaling mediate TNF-{alpha}-induced MMP-9 expression. Black-Right-Pointing-Pointer SIN1 knockdown showed no significant effect on MMP-9 expression by TNF-{alpha}. -- Abstract: Tumor necrosis factor-alpha (TNF-{alpha}) promotes in vitro retinal pigment epithelial (RPE) cell migration to initiate proliferative vitreoretinopathy (PVR). Here we report that TNF-{alpha} promotes human RPE cell migration by inducing matrix metallopeptidase 9 (MMP-9) expression. Inhibition of MMP-9 by its inhibitor or its neutralizing antibody inhibited TNF-{alpha}-induced in vitro RPE cell migration. Reversely, exogenously-added active MMP-9 promoted RPE cell migration. Suppression Akt/mTOR complex 1(mTORC1) activation by LY 294002 and rapamycin inhibited TNF-{alpha}-mediated MMP-9 expression. To introduce a constitutively active Akt (CA-Akt) in cultured RPE cells increased MMP-9 expression, and to block mTORC1 activation by rapamycin inhibited its effect. RNA interference (RNAi)-mediated silencing of SIN1, a key component of mTOR complex 2 (mTORC2), had no effect on MMP-9 expression or secretion. In conclusion, this study suggest that TNF-{alpha} promotes RPE cell migration by inducing MMP-9 expression through activation of Akt/ mTORC1, but not mTORC2 signaling.

First light - II. Emission line extinction, population III stars, and X-ray binaries

Science.gov (United States)

Barrow, Kirk S. S.; Wise, John H.; Aykutalp, Aycin; O'Shea, Brian W.; Norman, Michael L.; Xu, Hao

2018-02-01

We produce synthetic spectra and observations for metal-free stellar populations and high-mass X-ray binaries in the Renaissance Simulations at a redshift of 15. We extend our methodology from the first paper in the series by modelling the production and extinction of emission lines throughout a dusty and metal-enriched interstellar and circum-galactic media extracted from the simulation, using a Monte Carlo calculation. To capture the impact of high-energy photons, we include all frequencies from hard X-ray to far-infrared with enough frequency resolution to discern line emission and absorption profiles. The most common lines in our sample in order of their rate of occurrence are Ly α, the C IV λλ1548, 1551 doublet, H α, and the Ca II λλλ8498, 8542, 8662 triplet. The best scenario for a direct observation of a metal-free stellar population is a merger between two Population III Galaxies. In mergers between metal-enriched and metal-free stellar populations, some characteristics may be inferred indirectly. Single Population III galaxies are too dim to be observed photometrically at z = 15. Ly α emission is discernible by JWST as an increase in J200w - J277w colour off the intrinsic stellar tracks. Observations of metal-free stars will be difficult, though not impossible, with the next generation of space telescopes.

H α and H β Raman scattering line profiles of the symbiotic star AG Pegasi

Science.gov (United States)

Lee, Seong-Jae; Hyung, Siek

2018-04-01

The H α and H β line profiles of the symbiotic star AG Pegasi, observed in 1998 September (phase ϕ = 10.24), display top narrow double Gaussian components and bottom broad components (FWHM = 200-400 km s-1). The photoionization model indicates that the ionized zone, responsible for the hydrogen Balmer and Lyman lines, is radiation-bounded, with a hydrogen gas number density of nH ˜ 109.85 cm-3 and a gas temperature of Te = 12 000-15 000 K. We have carried out Monte Carlo simulations to fit the Raman scattering broad wings, assuming that the hydrogen Ly β and Ly γ lines emitted within the radiation-bounded H II zone around a white dwarf have the same double Gaussian line profile shape as the hydrogen Balmer lines. The simulation shows that the scattering H I zones are attached to (or located just outside) the inner H II shells. The best fit to the observed broad H I line profiles indicates that the column density of the scattering neutral zone is NH ≃ 3-5 × 1019 cm-2. We have examined whether the geometrical structure responsible for the observed H α and H β line profiles is a bipolar conical shell structure, consisting of the radiation-bounded ionized zone and the outer material bounded neutral zone. The expanding bipolar structure might be two opposite regions of the common envelope or the outer shell of the Roche lobe around the hot white dwarf, formed through the mass inflows from the giant star and pushed out by the fast winds from the hot white dwarf.

Quasar Absorption in the UV: Probing the Intergalactic Medium

Science.gov (United States)

Weinberg, David; Katz, Neal

1998-01-01

The purpose of this project is to model the low-redshift Lyman-alpha forest and exploration of the relation between Lyman-alpha absorbers and galaxies. This paper shows that the simulation models that are so successful at explaining properties of the high-redshift forest also account for the most important results of observational studies of the low-redshift forest, from HST (especially the Quasar Absorption Line Key Project) and ground-based follow-up.

The End of the Lines for OX 169: No Binary Broad-Line Region

Science.gov (United States)

Halpern, J. P.; Eracleous, M.

2000-03-01

We show that unusual Balmer emission-line profiles of the quasar OX 169, frequently described as either self-absorbed or double peaked, are actually neither. The effect is an illusion resulting from two coincidences. First, the forbidden lines are quite strong and broad. Consequently, the [N II] λ6583 line and the associated narrow-line component of Hα present the appearance of twin Hα peaks. Second, the redshift of 0.2110 brings Hβ into coincidence with Na I D at zero redshift, and ISM absorption in Na I D divides the Hβ emission line. In spectra obtained over the past decade, we see no substantial change in the character of the line profiles and no indication of intrinsic double-peaked structure. The Hγ, Mg II, and Lyα emission lines are single peaked, and all of the emission-line redshifts are consistent once they are correctly attributed to their permitted and forbidden-line identifications. A systematic shift of up to 700 km s-1 between broad and narrow lines is seen, but such differences are common and could be due to gravitational and transverse redshift in a low-inclination disk. Stockton & Farnham had called attention to an apparent tidal tail in the host galaxy of OX 169 and speculated that a recent merger had supplied the nucleus with a coalescing pair of black holes that was now revealing its existence in the form of two physically distinct broad-line regions. Although there is no longer any evidence for two broad emission-line regions in OX 169, binary black holes should form frequently in galaxy mergers, and it is still worthwhile to monitor the radial velocities of emission lines that could supply evidence of their existence in certain objects.