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We use cosmological hydrodynamic simulations with stellar feedback from the FIRE project to study the physical nature of Lyman limit systems (LLSs) at z<1. At these low redshifts, LLSs are closely associated with dense gas structures…

In this paper we investigate the possible reasons why HI 21-cm absorption in damped Lyman-alpha systems (DLAs) has only been detected at low redshift... We suggest that the lack of 21-cm absorption detections at high redshift arises from…

天体物理学 · 物理学 2009-11-11 S. J. Curran , J. K. Webb

LCDM is remarkably successful in predicting the cosmic microwave background and large-scale structure, and LCDM parameters have been determined with only mild tensions between different types of observations. Hydrodynamical simulations…

星系天体物理 · 物理学 2015-05-13 Joel R. Primack

Using the Sloan Digital Sky Survey, Data Release 5, we survey proximate damped Lya systems (PDLAs): absorption line systems with HI column density N(HI)> 2x10^20 cm^{-2} at velocity separation dv < 3000 km/s from their background quasar.…

天体物理学 · 物理学 2009-11-13 Jason X. Prochaska , Joseph F. Hennawi , Stephane Herbert-Fort

Utilizing a new, high mass resolution hydrodynamic simulation we compute the metallicity evolution of damped Lyman alpha systems (DLAs) and find a reasonable agreement with observations. In particular, the observed slow evolution of the DLA…

天体物理学 · 物理学 2009-11-07 Renyue Cen , Jeremiah P. Ostriker , Jason X. Prochaska , Arthur M. Wolfe

This paper presents chemical abundance measurements for 12 new z>3 damped Lya systems discovered toward five quasars from the Palomar Sky Survey. We determine HI column densities from profile fits to the observed damped Lya profiles and…

天体物理学 · 物理学 2009-11-07 Jason X. Prochaska , Sandra Castro , S. G. Djorgovski

We apply a physically motivated stellar feedback model to analyse the statistical properties of damped Lyman-alpha systems (DLAs) expected in the concordance cold dark matter (CDM) model. Our feedback model produces extended low-metallicity…

天体物理学 · 物理学 2009-11-11 P. H. Johansson , G. Efstathiou

We compare the results of thirteen cosmological gasdynamical codes used to simulate the formation of a galaxy in the LCDM structure formation paradigm. The various runs differ in their hydrodynamical treatment (SPH, moving-mesh and AMR) but…

We examine in detail the dynamical structure of an elliptical galaxy simulated in the Lambda CDM scenario. The morphology of the galaxy evolves dramatically over time in response to the mode and timing of mass accretion; smooth deposition…

天体物理学 · 物理学 2009-11-07 Andres Meza , Julio F. Navarro , Matthias Steinmetz , Vincent R. Eke

We study the predicted sub-mm emission from massive galaxies in a Lambda-CDM universe, using hydrodynamic cosmological simulations. Assuming that most of the emission from newly formed stars is absorbed and reradiated in the rest-frame…

天体物理学 · 物理学 2007-05-23 Mark A. Fardal , Neal Katz , David H. Weinberg , Romeel Davé , Lars Hernquist

Measurements of element abundances in damped Lyman alpha systems are providing new means to investigate the chemical evolution of galaxies, particularly at early times. We review progress in this area, concentrating on recent efforts to…

天体物理学 · 物理学 2016-08-30 M. Pettini , D. L. King , L. J. Smith , R. W. Hunstead

We present results from an efficient, non-traditional survey to discover damped Lyman-alpha (DLA) absorption-line systems with neutral hydrogen column densities N(HI)>2x10^{20} atoms cm^{-2} and redshifts z<1.65. Contrary to previous…

天体物理学 · 物理学 2007-05-23 Sandhya Rao

We use high resolution Eulerian hydrodynamics simulations to study kinematic properties of the low ionization species in damped Ly-alpha systems at redshift z=3. Our adaptive mesh refinement simulations include most key ingredients relevant…

天体物理学 · 物理学 2009-11-13 Alexei O. Razoumov , Michael L. Norman , Jason X. Prochaska , Arthur M. Wolfe

An analysis of voids using cosmological N-body simulations of cold dark matter models is presented. It employs a robust statistics of voids, that was recently applied to discriminate between data from the Las Campanas Redshift Survey and…

天体物理学 · 物理学 2009-11-07 S. Arbabi-Bidgoli , V. Mueller

We use medium- and high-resolution spectroscopy of close pairs of quasars to analyze the circumgalactic medium (CGM) surrounding 32 damped Ly$\alpha$ absorption systems (DLAs). The primary quasar sightline in each pair probes an intervening…

Only by incorporating various forms of feedback can theories of galaxy formation reproduce the present-day luminosity function of galaxies. It has also been argued that such feedback processes might explain the counter-intuitive behaviour…

天体物理学 · 物理学 2009-11-13 M. J. Stringer , A. J. Benson , K. Bundy , R. S. Ellis , E. L. Quetin

Essentially all high-redshift galaxies show evidence for strong large-scale outflows that should have a profound effect on the structure and kinematics of both the galaxies themselves and their environment. The interstellar absorption…

天体物理学 · 物理学 2009-11-07 Joop Schaye

Using galaxies as background light sources to map the Lya absorption lines is a novel approach to study Damped Lya Absorbers (DLAs). We report the discovery of an intervening z = 3.335 +- 0.007 DLA along a galaxy sight-line identified among…

星系天体物理 · 物理学 2016-02-03 K. Mawatari , A. K. Inoue , K. Kousai , T. Hayashino , R. Cooke , J. X. Prochaska , T. Yamada , Y. Matsuda

We perform a spectrophotometric analysis of galaxies at redshifts z = 4 - 6 in cosmological SPH simulations of a Lambda CDM universe. Our models include radiative cooling and heating by a uniform UV background, star formation, supernova…

天体物理学 · 物理学 2009-11-10 Christopher Night , Kentaro Nagamine , Volker Springel , Lars Hernquist

Determining the spatial distribution and intrinsic physical properties of neutral hydrogen on cosmological scales is one of the key goals of next-generation radio surveys. We use the EAGLE galaxy formation simulations to assess the…