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Related papers: Through Thick and Thin - HI Absorption in Cosmolog…

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We model the complex distribution of atomic hydrogen (HI) in the interstellar medium (ISM) assuming that it is driven entirely by supernovae (SN). We develop and assess two different models. In the first approach, the simulated volume is…

Astrophysics · Physics 2009-11-11 Jacqueline A. Hodge , Avinash A. Deshpande

An intriguing fact about cosmic gas clouds is that they all appear to have neutral (atomic) hydrogen column densities smaller than 10^{22} cm^{-2}. Observations of damped Ly-alpha (DLA) absorption systems further indicate that the maximum…

Astrophysics · Physics 2009-11-07 Joop Schaye

We discuss the effects of gravitational collapse on the shape of absorption line profiles for low column density (log N(HI) < 14) Lyman Alpha forest clouds and argue by comparison with cosmological simulations that Lyman alpha forest…

Astrophysics · Physics 2016-01-27 Michael Rauch

We present a detailed study of the hydrogen density distribution in the local interstellar medium (ISM) using the X-ray absorption technique. Hydrogen column densities were precisely measured by fitting X-ray spectra from coronal sources…

High Energy Astrophysical Phenomena · Physics 2024-08-28 E. Gatuzz , J. Wilms , A. Zainab , S. Freund , P. C. Schneider , J. Robrade , S. Czesla , J. A. García , T. R. Kallmanınst

Using data on the HI column density distribution in the local Universe, f(N_{HI}), we show how to determine g(N_{H}), the distribution of the total gas (HI+HII) column density. A simple power law fit to f(N_{HI}) fails due to bendings in…

Astrophysics · Physics 2009-11-07 Edvige Corbelli , Rino Bandiera

We devise a physical model of formation and distribution of molecular gas clouds in galaxies. We use the model to predict the intensities of rotational transition lines of carbon monoxide (CO) and the molecular hydrogen (H$_{\rm 2}$)…

Astrophysics of Galaxies · Physics 2020-10-14 Shigeki Inoue , Naoki Yoshida , Hidenobu Yajima

Absorption line studies are essential to understanding the origin, nature, and impact of starburst-driven galactic outflows. Such studies have revealed a multiphase medium with a number of poorly-understood features leading to a need to…

Astrophysics of Galaxies · Physics 2018-09-19 J'Neil Cottle , Evan Scannapieco , Marcus Bruggen

We present results from the Keck Baryonic Structure Survey (KBSS), a unique spectroscopic survey designed to explore the connection between galaxies and intergalactic baryons. The KBSS is optimized for the redshift range z ~ 2-3, combining…

Simulations of an isolated Milky Way-like galaxy, in which supernovae power a galactic fountain, reproduce the observed velocity and 21cm brightness statistics of galactic neutral hydrogen (HI). The simulated galaxy consists of a thin HI…

Astrophysics · Physics 2012-03-19 C. M. Booth , Tom Theuns

Damped Lyman-alpha systems (DLAs) are useful probes of star formation and galaxy formation at high redshift. We study the physical properties of DLAs and their relationship to Lyman-break galaxies using cosmological hydrodynamic simulations…

Astrophysics · Physics 2008-11-26 Kentaro Nagamine

We study the physical conditions of the circum-galactic medium (CGM) around z=0.25 galaxies as traced by HI and metal line absorption, using cosmological hydrodynamic simulations that include galactic outflows. Using lines of sight targeted…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-17 Amanda Brady Ford , Benjamin D. Oppenheimer , Romeel Davé , Neal Katz , Juna A. Kollmeier , David H. Weinberg

We introduce a sub-grid model for the non-equilibrium abundance of molecular hydrogen in cosmological simulations of galaxy formation. We improve upon previous work by accounting for the unresolved structure of molecular clouds in a…

Astrophysics of Galaxies · Physics 2015-06-19 Matteo Tomassetti , Cristiano Porciani , Emilio Romano-Diaz , Aaron D. Ludlow

We investigate cool HI gas traced by Lyman series absorption around 256 galaxies at z ~ 0.48 (median stellar mass, log10(M*/Msun) = 8.7) using 15 background quasars (median impact parameter, D = 140 pkpc), as part of the MUSE Quasar-fields…

We use adaptive mesh refinement cosmological simulations to study the spatial distribution and covering fraction of OVI absorption in the circumgalactic medium (CGM) as a function of projected virial radius and azimuthal angle. We compare…

Most detected neutral atomic hydrogen (HI) at low redshift is associated with optically bright galaxies. However, a handful of HI clouds are known which appear to be optically dark and have no nearby potential progenitor galaxies, making…

Astrophysics of Galaxies · Physics 2018-05-23 Rhys Taylor , Richard Wünsch , Jan Palouš

We analyze the low-redshift (z~0.2) circumgalactic medium by comparing absorption-line data from the COS-Halos Survey to absorption around a matched galaxy sample from two cosmological hydrodynamic simulations. The models include different…

We develop a new method to constrain the physical conditions in the cool (~10^4 K) circumgalactic medium (CGM) from measurements of ionic column densities, by assuming that the cool CGM spans a large range of gas densities and that small…

Astrophysics of Galaxies · Physics 2016-10-26 Jonathan Stern , Joseph F. Hennawi , J. Xavier Prochaska , Jessica K. Werk

We carried out synthetic observations of interstellar atomic hydrogen at 21cm wavelength by utilizing the magneto-hydrodynamical numerical simulations of the inhomogeneous turbulent interstellar medium (ISM) Inoue and Inutsuka (2012). The…

Measuring rest-frame ultraviolet rotational transitions from the Lyman and Werner bands in absorption against a bright background continuum is one of the few ways to directly measure molecular hydrogen (H2). Here we report the detection of…

We investigate large-scale gas kinematics in the multiphase circumgalactic medium (CGM) using the observed correlation between line width (Doppler $b$ parameter) and column density ($N$) for H I and O VI absorbers. Leveraging extensive…

Astrophysics of Galaxies · Physics 2026-02-25 Zhijie Qu , Hsiao-Wen Chen , Eliana Schiller , Jing Wang , Max Gronke