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We calculate theoretical population ratios of the ground fine-structure levels of some atoms/ions which typically exhibit UV lines in the spectra of QSO absorbers redward the Ly-alpha forest: C0, C+, O0, Si+ and Fe+. The most reliable…

Astrophysics · Physics 2009-10-31 A. I. Silva , S. M. Viegas

We study the physical properties of a homogeneous sample of 157 optically-thick absorption line systems at redshifts ~1.8-4.4, selected from a high-dispersion spectroscopic survey of Lyman limit systems (LLSs). By means of multiple…

Astrophysics of Galaxies · Physics 2015-12-09 Michele Fumagalli , John M. O'Meara , J. Xavier Prochaska

We estimate the abundance of dust in damped Lyman-{\alpha} absorbers (DLAs) by statistically measuring the excess reddening they induce on their background quasars. We detect systematic reddening behind DLA consistent with the SMC type…

Astrophysics of Galaxies · Physics 2015-06-19 Masataka Fukugita , Brice Ménard

We argue that the lack of observed damped Lyman alpha (DLA) systems that simultaneously have high HI columns densities and high metallicities results naturally from the formation of molecules in the cold phase of a two-phase atomic medium…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-11 Mark R. Krumholz , Sara L. Ellison , J. Xavier Prochaska , Jason Tumlinson

We are conducting COLD GASS, a legacy survey for molecular gas in nearby galaxies. Using the IRAM 30m telescope, we measure the CO(1-0) line in a sample of ~350 nearby (D=100-200 Mpc), massive galaxies (log(M*/Msun)>10.0). The sample is…

We investigate the physical processes occuring in the multiphase gas of a damped Ly\alpha system (DLA). We base our analysis on a high quality Keck HIRES spectrum of the QSO J1211+0422 in which a DLA is detected at z=2.377. There is little…

Astrophysics · Physics 2009-11-13 N. Lehner , J. C. Howk , J. X. Prochaska , A. M. Wolfe

Observations of damped Ly-alpha absorbers (DLA) indicate that the fraction of hydrogen in its neutral form (HI) is significant by mass at all redshifts. This gas represents the reservoir of material that is available for star formation at…

Astrophysics · Physics 2015-05-13 Stuart Wyithe

We present ALMA observations of the [C II] 158 micron fine structure line and dust continuum emission from the host galaxies of five redshift 6 quasars. We also report complementary observations of 250 GHz dust continuum and CO (6-5) line…

A broad array of interstellar absorption features that appear in the ultraviolet spectra of bright sources allows us to measure the abundances and ionization states of many important heavy elements that exist as free atoms in the…

Astrophysics · Physics 2007-05-23 Edward B. Jenkins

An accurate value of the deuterium/hydrogen (D/H) ratio in the local interstellar medium (LISM) and a better understanding of the D/H variations with position in the Galactic disk can provide essential information on the primordial D/H…

Astrophysics · Physics 2009-11-16 Jeffrey L. Linsky

We present the direct detection of molecular hydrogen at the highest redshift known today (z_abs=4.224) in a Damped Lyman-alpha (DLA) system toward the quasar PSS J1443+2724. This absorber is remarkable for having one of the highest…

Astrophysics · Physics 2009-11-11 C. Ledoux , P. Petitjean , R. Srianand

We present an analysis of the molecular and atomic gas emission in the rest-frame far-infrared and sub-millimetre, from the lensed z=2.3 sub-millimetre galaxy SMM J2135-0102. We obtain very high signal-to-noise detections of 11 transitions…

We present a survey undertaken with the Atacama Large Millimeter/submillimeter Array (ALMA) to study the galaxies associated with a representative sample of 16 damped Ly-alpha absorbers (DLAs) at z~4.1-4.5, using the [CII]-158-micron…

Astrophysics of Galaxies · Physics 2025-04-08 Marcel Neeleman , Nissim Kanekar , J. Xavier Prochaska , Marc A. Rafelski , Lordrick A. Kahinga

Damped Ly$\alpha$ absorbers (DLAs) are the highest \HI\ column density (\NHI) absorption line systems detected in the spectra of background quasars. DLAs dominate the neutral gas content of the Universe ($\Omega_{\rm HI}$) and are used to…

We have examined some basic properties of damped Ly$\alpha$ systems(DLAs) by semi-analytic model. We assume that DLA hosts are disk galaxies whose mass function is generated by Press-Schechter formulism at redshift 3. Star formation and…

Astrophysics · Physics 2008-11-26 J. L. Hou , C. G. Shu , S. Y. Shen , R. X. Chang

We present results from a search for galaxies that give rise to damped Lyman alpha (DLA), subDLA, and Lyman limit system (LLS) absorption at redshifts 0.1 ~< z ~< 1 in the spectra of background quasars. The sample was formed from a larger…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Sandhya M. Rao , Michele Belfort-Mihalyi , David A. Turnshek , Eric M. Monier , Daniel B. Nestor , Anna M. Quider

Analysis of interstellar absorption lines observed in high-resolution {\em HST} spectra of nearby stars provides temperatures, turbulent velocities, and kinetic properties of warm interstellar clouds. Previous studies identified 15 warm…

Astrophysics of Galaxies · Physics 2022-08-31 Jeffrey L. Linsky , Seth Redfield , Diana Ryder , Adina Chasan-Taber

Recent searches for the hosts of high-redshift ($z \sim 4$) damped Ly$\alpha$ absorbers (DLAs) have detected bright galaxies at distances of tens of kpc from the DLA. Using the FIRE-2 cosmological zoom simulations, we argue that these…

We present the results of a single-dish beam-matched survey of the three lowest rotational transitions of CO in a sample of 20 local (D < 70 Mpc) Luminous Compact Blue Galaxies (LCBGs). These ~L*, blue, high surface brightness, starbursting…

Astrophysics · Physics 2009-11-10 C. A. Garland , J. P. Williams , D. J. Pisano , R. Guzman , F. J. Castander , J. Brinkmann

We investigate the properties of damped Ly{\alpha} absorption systems (DLAs) in semi-analytic models of galaxy formation, including partitioning of cold gas in galactic discs into atomic, molecular, and ionized phases with a molecular…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Michael Berry , Rachel S. Somerville , Marcel R. Haas , Eric Gawiser , Ari Maller , Gergo Popping , Scott C. Trager
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