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We combine cosmological, hydrodynamical simulations with accurate radiative transfer corrections to investigate the relation between strong HI absorbers (N_HI >~ 10^17 /cm^2) and galaxies at redshift z = 3. We find a strong anti-correlation…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-19 Alireza Rahmati , Joop Schaye

We present a study of HI-rich galaxies in the local universe selected from blind emission-line surveys. These galaxies represent the emission-line counterparts of local damped Lyman-alpha systems. We find that the HI cross-section of…

Astrophysics · Physics 2007-05-23 Jessica L. Rosenberg , Stephen E. Schneider

Mapping stars and gas in nearby galaxies is fundamental for understanding their growth and the impact of their environment. This issue is addressed by comparing the stellar "edges" of galaxies $D_{\rm stellar}$, defined as the outermost…

In order to investigate the contribution of diffuse components to their total HI emission, we have obtained high precision HI line flux densities with the 100m Green Bank Telescope for a sample of 100 isolated spiral and irregular galaxies…

Astrophysics · Physics 2008-11-26 David E. Hogg , Morton S. Roberts , Martha P. Haynes , Ronald J. Maddalena

We determine the intrinsic axial ratio distribution of the 'gas' disks of extremely faint M_B > -14.5 dwarf irregular galaxies. We start with the measured (beam corrected) distribution of apparent axial ratios in the HI 21cm images of dwarf…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-04 Sambit Roychowdhury , Jayaram N. Chengalur , Ayesha Begum , Igor D. Karachentsev

Dwarf irregular galaxies are unique laboratories for studying the interaction between stars and the interstellar medium in low mass environments. We present the highest spatial resolution observations to date of the neutral hydrogen content…

Astrophysics · Physics 2009-11-13 Amanda Kepley , Eric Wilcots , Deidre Hunter , Tyler Nordgren

The neutral atomic hydrogen (HI) mass function (HIMF) describes the distribution of the HI content of galaxies at any epoch; its evolution provides an important probe of models of galaxy formation and evolution. Here, we report Giant…

Astrophysics of Galaxies · Physics 2022-11-30 Apurba Bera , Nissim Kanekar , Jayaram N. Chengalur , Jasjeet S. Bagla

We present new results on the frequency distribution of projected HI column densities f(N,X), total comoving covering fraction, and integrated mass densities rho_HI of high redshift, HI `disks' from a survey of damped Lya systems (DLAs) in…

Astrophysics · Physics 2009-11-13 J. Xavier Prochaska , Arthur M. Wolfe

We present deep H$\alpha$ imaging of three nearby dwarf galaxies, carefully selected to optimize observations with the Maryland-Magellan Tunable Filter (MMTF) on the Magellan 6.5m telescope. An effective bandpass of $\sim$13\AA\ is used,…

Astrophysics of Galaxies · Physics 2016-02-17 Janice C. Lee , Sylvain Veilleux , Michael McDonald , Bryan Hilbert

We present the results of Hi line observations towards 26 Active Galactic Nuclei (AGN)-hosting and one star-forming dwarf galaxies (Mstar < 10^9.5 Msun) with the 19-beam spectral line receiver of FAST at 1.4 GHz. Our FAST observed targets…

Astrophysics of Galaxies · Physics 2025-12-01 Hong-Ying Chen , Chao-Wei Tsai , Pei Zuo , Niankun Yu , Jialai Wang , Kai Zhang , Guodong Li , Yogesh Chandola , Zheng Zheng , Jingwen Wu , Di Li , Lulu Bao

We compare the properties of a sample of local (z=0) gas-rich galaxies studied in 21 cm emission to a sample of 13 low-redshift (z < 1) damped Lyman alpha (DLA) galaxies identified as the counterparts of low-redshift DLA systems found in…

Astrophysics · Physics 2007-05-23 David A. Turnshek , Sandhya M. Rao , Daniel B. Nestor

As part of a large study to map the distribution of star formation across galactic disks, we have obtained deep Halpha images of the nearby Sculptor Group spirals NGC 247 and NGC 7793. These images are of sufficiently high quality that they…

We investigate how damped Lyman-$\alpha$ absorbers (DLAs) at z ~ 2-3, detected in large optical spectroscopic surveys of quasars, trace the population of star-forming galaxies. Building on previous results, we construct a model based on…

Astrophysics of Galaxies · Physics 2020-05-27 J. -K. Krogager , P. Møller , L. B. Christensen , P. Noterdaeme , J. P. U. Fynbo , W. Freudling

We present the observations and first results from the FIGGS2 survey. FIGGS2 is an extension of the earlier Faint Irregular Galaxies GMRT survey (FIGGS) towards faint luminosity end. The sample consists of 20 galaxies of which 15 were…

Astrophysics of Galaxies · Physics 2016-09-06 Narendra Nath Patra , Jayaram N. Chengalur , Igor D. Karachentsev , Margarita E. Sharina

We use the ALFALFA HI survey to examine whether the cold gas reservoirs of galaxies are inhibited or enhanced in large-scale filaments. Our sample includes 9947 late-type galaxies with HI detections, and 4236 late-type galaxies with…

We combine predictions for several hierarchical cosmogonies with observational evidence on damped Lyman alpha systems to establish a correspondence between the high redshift galaxy population and the properties of damped Lyman alpha…

Astrophysics · Physics 2009-10-31 Martin G. Haehnelt , Matthias Steinmetz , Michael Rauch

We measure the z=0 B-band optical luminosity function (LF) for galaxies selected in a blind HI survey. The total LF of the HI selected sample is flat, with Schechter parameters M*=-19.38_{-0.62}^{+1.02} + 5 log h mag and…

Astrophysics · Physics 2009-11-06 M. A. Zwaan , F. H. Briggs , D. Sprayberry

We present a statistical study of the properties of diffuse HI in ten nearby galaxies, comparing the HI detected by the single-dish telescope FAST (FEASTS program) and the interferometer VLA (THINGS program), respectively. The THINGS'…

Quasar absorbers provide a powerful observational tool with which to probe both galaxies and the intergalactic medium up to high redshift. We present a study of the evolution of the column density distribution, f(N,z), and total neutral…

Astrophysics · Physics 2007-05-23 Celine Peroux , Mike J. Irwin , Richard G. McMahon , Lisa J. Storrie-Lombardi

We present an analysis of the neutral hydrogen (HI) properties of a fully cosmological hydrodynamical dwarf galaxy, run with varying simulation parameters. As reported by Governato et al. (2010), the high resolution, high star formation…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 K. Pilkington , B. K. Gibson , F. Calura , A. M. Brooks , L. Mayer , C. B. Brook , G. S. Stinson , R. J. Thacker , C. G. Few , D. Cunnama , J. Wadsley