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Related papers: Understanding the H2/HI Ratio in Galaxies

200 papers

We show that the ratio of molecular to atomic gas in galaxies is determined by hydrostatic pressure and that the relation between the two is nearly linear. The pressure relation is shown to be good over three orders of magnitude for 14…

Astrophysics · Physics 2008-11-26 Leo Blitz , Erik Rosolowsky

We study the relations between the mass of the central black hole (BH) $M_{\rm BH}$, the dark matter halo mass $M_{\rm h}$, and the stellar-to-halo mass fraction $f_\star\propto M_\star/M_{\rm h}$ in a sample of $55$ nearby galaxies with…

Astrophysics of Galaxies · Physics 2021-08-25 A. Marasco , G. Cresci , L. Posti , F. Fraternali , F. Mannucci , A. Marconi , F. Belfiore , S. M. Fall

We use a sample of 47 homogeneous and high sensitivity CO images taken from the Nobeyama and BIMA surveys to demonstrate that, contrary to common belief, a significant number (~40%) of HI-deficient nearby spiral galaxies are also depleted…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 Michele Fumagalli , Mark R. Krumholz , J. Xavier Prochaska , Giuseppe Gavazzi , Alessandro Boselli

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 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 examine the global HI properties of galaxies in quarter-billion particle cosmological simulations using Gadget-2, focusing on how galactic outflows impact HI content. We consider four outflow models, including a new one (ezw) motivated…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Romeel Davé , Neal Katz , Benjamin D. Oppenheimer , Juna A. Kollmeier , David H. Weinberg

We study the impact of molecular (${\rm H_2}$) and atomic (HI) hydrogen cooling on the galaxy formation threshold. We calculate the fraction of dark matter (DM) halos that exceeds a critical mass required for star formation,…

Astrophysics of Galaxies · Physics 2025-04-09 Ethan O. Nadler

The local HI mass function (HIMF), like the optical luminosity function, is an important observational input into models of cosmology and galaxy evolution. It is a helpful framework for assessing the number density of gas rich dwarf…

Astrophysics · Physics 2007-05-23 Martin Zwaan

We present a multi-scale analysis of molecular hydrogen in a Milky Way-like simulated galaxy. Our census covers the gas content of the entire disc, to radial profiles and the Kennicutt-Schmidt relation, to a study of its molecular clouds,…

Astrophysics of Galaxies · Physics 2019-01-16 Sarah Nickerson , Romain Teyssier , Joakim Rosdahl

We present a comprehensive analysis of atomic hydrogen (HI) properties using a semi-analytical model of galaxy formation and N-body simulations covering a large cosmological volume at high resolution. We examine the HI mass function and the…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-11 Marta Spinelli , Anna Zoldan , Gabriella De Lucia , Lizhi Xie , Matteo Viel

Accurately modeling the cold gas content in the universe is challenging for current theoretical models. We propose a new empirical model NeutralUniverseMachine for the evolution of HI and H$_2$ gas along with dark matter halos based on the…

Astrophysics of Galaxies · Physics 2023-08-03 Hong Guo , Jing Wang , Michael G. Jones , Peter Behroozi

We show in this paper why molecular millimeter absorption line searches in DLAs have been unsuccessful. We use CO emission line maps of local galaxies to derive the H2 column density distribution function f(N_H2) at z=0. We show that it…

Astrophysics · Physics 2009-11-11 M. A. Zwaan , J. X. Prochaska

We use the catalogue of 4315 extragalactic HI 21-cm emission line detections from HIPASS to calculate the most accurate measurement of the HI mass function (HIMF) of galaxies to date. The completeness of the HIPASS sample is well…

Astrophysics · Physics 2009-11-10 M. A. Zwaan , M. J. Meyer , L. Staveley-Smith , R. L. Webster

In this study, we used the 13.7m telescope at Qinghai Station to observe CO data in 48 galaxies in Virgo clusters, of which 41 sources observed CO signals. The properties of molecular gas are deduced by co-to-$H_2$ factor. We also collected…

Astrophysics of Galaxies · Physics 2025-03-11 ZhiYong Hu , JingFu Hu , YiPing Ao

Recent results have suggested that the well known mass-metallicity relation has a strong dependence on the star formation rate, to the extent that a three dimensional `fundamental metallicity relation' exists which links the three…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 M. S. Bothwell , R. Maiolino , R. Kennicutt. , G. Cresci , F. Mannucci , A. Marconi , C. Cicone

We construct the halo mass function (HMF) from the GAMA galaxy group catalogue over the mass range 10^12.7M_sol to 10^15.5M_sol, and find good agreement with the expectation from LambdaCDM. In comparison to previous studies, this result…

We derive a non-parametric CO luminosity function using a FIR and an optical B-band selected sample of the galaxies included in the FCRAO Extragalactic CO Survey. The FIR selected sample is defined using the IRAS Bright Galaxy Surveys (BGS;…

Astrophysics · Physics 2009-11-07 Dusan Keres , Min S. Yun , J. S. Young

We study the connection of star formation to atomic (HI) and molecular hydrogen (H$_2$) in isolated, low metallicity dwarf galaxies with high-resolution ($m_{\rm gas}$ = 4 M$_\odot$, $N_{\rm ngb}$ = 100) SPH simulations. The model includes…

Astrophysics of Galaxies · Physics 2016-03-23 Chia-Yu Hu , Thorsten Naab , Stefanie Walch , Simon C. O. Glover , Paul C. Clark

Using IRAM 30m, SEST 15m, and Nancay radiotelescopes, we have gathered the 1mm continuum emission, spectra of the J=1--0 CO line and of the HI line at 21cm for two samples of IRAS galaxies. Using these data, we have estimated the HI masses,…

Astrophysics · Physics 2016-08-30 Paola Andreani , Fabienne Casoli , Maryvonne Gerin

Determining the efficiency with which gas is converted into stars in galaxies requires an accurate determination of the total reservoir of molecular gas mass. However, despite being the most abundant molecule in the Universe, H$_2$ is…