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Related papers: Understanding the H2/HI Ratio in Galaxies

200 papers

The HI gas content is a key ingredient in galaxy evolution, the study of which has been limited to moderate cosmological distances for individual galaxies due to the weakness of the hyperfine HI 21-cm transition. Here we present a new…

Astrophysics of Galaxies · Physics 2021-12-08 Kasper E. Heintz , Darach Watson , Pascal Oesch , Desika Narayanan , Suzanne C. Madden

We investigate the properties of cold gas at $10^4~\rm K$ around star-forming galaxies at $z~\sim~1$ using Mg II spectra through radiative transfer modeling. We utilize a comprehensive dataset of 624 galaxies from the MAGG and MUDF…

Astrophysics of Galaxies · Physics 2025-08-28 Seok-Jun Chang , Rajeshwari Dutta , Max Gronke , Michele Fumagalli , Fabrizio Arrigoni Battaia , Matteo Fossati

We analytically derive the observed size-mass relation of galaxies' atomic hydrogen (HI), including limits on its scatter, based on simple assumptions about the structure of HI discs. We trial three generic profiles for HI surface density…

We present a demographic analysis of integrated star formation and gas properties for a sample of galaxies representative of the overall population at z~0. This research was undertaken in order to characterise the nature of star formation…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 M. S. Bothwell , R. C. Kennicutt , J. C. Lee

To assess how external factors such as local interactions and fresh gas accretion influence the global ISM of galaxies, we analyze the relationship between recent enhancements of central star formation and total molecular-to-atomic (H2/HI)…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 David V. Stark , Sheila J. Kannappan , Lisa H. Wei , Andrew J. Baker , Adam K. Leroy , Kathleen D. Eckert , Stuart N. Vogel

We measure the CO-to-H$_2$ conversion factor ($\alpha_\mathrm{CO}$) in 37 galaxies at 2~kpc resolution, using dust surface density inferred from far-infrared emission as a tracer of the gas surface density and assuming a constant…

We know little about the outermost portions of galaxies because there is little light coming from them. We do know that in many cases atomic hydrogen (HI) extends well beyond the optical radius \cite{Casertano91}. In the centers of…

Astrophysics · Physics 2009-11-10 Jonathan Braine , Fabrice Herpin

Galaxies in Hickson Compact Groups (HCGs) are believed to experience morphological transformations from blue, star-forming galaxies to red, early-type galaxies. Galaxies with a high ratio between the luminosities of the warm H2 to the 7.7mu…

Astrophysics of Galaxies · Physics 2014-10-15 U. Lisenfeld , P. N. Appleton , M. E. Cluver , P. Guillard , K. Alatalo , P. Ogle

We study the properties of dark matter halos that contain star-forming galaxies at $1.43 \le z \le 1.74$ using the FMOS-COSMOS survey. The sample consists of 516 objects with a detection of the H$\alpha$ emission line, that represent the…

We extend the local stellar galaxy-(sub)halo connection to the atomic hydrogen (HI) component by seeding semi-empirically galaxies into a large N-body dark matter (DM) simulation. The main input to construct the mock galaxy catalogue are:…

Astrophysics of Galaxies · Physics 2021-07-08 A. R. Calette , Aldo Rodríguez-Puebla , Vladimir Avila-Reese , Claudia del P. Lagos

We study the properties of gas inside and around galaxy haloes as a function of radius and halo mass, focussing mostly on z=2, but also showing some results for z=0. For this purpose, we use a suite of large cosmological, hydrodynamical…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Freeke van de Voort , Joop Schaye

We report the results of initial FUSE observations of molecular hydrogen (H2) in translucent clouds. These clouds have greater optical depth than any of the diffuse clouds previously observed for far-UV H2 absorption, and provide new…

Mass models of 15 nearby dwarf and spiral galaxies are presented. The galaxies are selected to be homogeneous in terms of the method used to determine their distances, the sampling of their rotation curves (RCs) and the mass-to-light ratio…

Astrophysics of Galaxies · Physics 2015-06-18 Toky Randriamampandry , Claude Carignan

Spatially resolved HI studies of dwarf galaxies have provided a wealth of precision data. However these high-quality, resolved observations are only possible for handful of dwarf galaxies in the Local Volume. Future HI surveys are unlikely…

Astrophysics of Galaxies · Physics 2018-06-06 A. Lopez-Sanchez , C. D. P. Lagos , T. Young , H. Jerjen

We derive the total cold gas, atomic hydrogen, and molecular gas masses of approximately 24 000 galaxies covering four decades in stellar mass at redshifts 0.5 < z < 3.0, taken from the CANDELS survey. Our inferences are based on the…

We present models of the evolution of the gaseous and stellar content of galaxies incorporating the formation of H_2 out of HI gas as part of such a model. We do so by formulating a subgrid model for gas clouds that uses well-known cloud…

Astrophysics · Physics 2009-11-11 F. I. Pelupessy , P. P. Papadopoulos , P. P. van der Werf

We present a study of the molecular gas properties in a sample of 98 HI - flux selected spiral galaxies within $\sim25$ Mpc, using the CO $J=3-2$ line observed with the James Clerk Maxwell Telescope. We use the technique of survival…

We examine the dependence between hydrogen total mass $M_{HI}$ and rotation speed $V_{rot}$, optical size $D_{25}$ or disc radial scale $R_0$ for two samples of late-type galaxies: a) isolated galaxy (AMIGA sample), and b) the edge-on…

Astrophysics of Galaxies · Physics 2017-07-26 Analoty V. Zasov , Natalia A. Zaitseva

We exploit a large, complete optical diameter and HI flux limited sample of spiral galaxies with types later than S0a to derive a robust measurement of the HI mass function (HIMF) for masses log(M_HI/M_Sun) > 7.4 which takes into account…

Astrophysics · Physics 2009-11-10 Christopher M. Springob , Martha P. Haynes , Riccardo Giovanelli

We examine the abundance of molecular hydrogen (H2) in the spectra of gamma ray burst afterglows (GRBs). In nearby galaxies H2 traces the cold neutral medium (CNM) and dense molecular star-forming interstellar gas. Though H2 is detected in…