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Related papers: Understanding the H2/HI Ratio in Galaxies

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We investigate the atomic (HI) and molecular (H_2) Hydrogen content of normal galaxies by combining observational studies linking galaxy stellar and gas budgets to their host dark matter (DM) properties, with a physically grounded galaxy…

Astrophysics of Galaxies · Physics 2010-05-25 M. Cook , C. Evoli , E. Barausse , G. L. Granato , A. Lapi

We present new empirical constraints on the evolution of $\rho_{\rm H_2}$, the cosmological mass density of molecular hydrogen, back to $z\approx2.5$. We employ a statistical approach measuring the average observed $850\mu{\rm m}$ flux…

We present the molecular gas mass fraction ($f_\mathrm{H_2}$) and star-formation efficiency (SFE) of local galaxies on the basis of our new CO($J=1-0$) observations with the Nobeyama 45m radio telescope, combined with the COLDGASS galaxy…

Modelling the molecular gas that is routinely detected through CO observations of high-redshift galaxies constitutes a major challenge for ab initio simulations of galaxy formation. We carry out a suite of cosmological hydrodynamic…

Astrophysics of Galaxies · Physics 2020-09-04 Alexander Schäbe , Emilio Romano-Díaz , Cristiano Porciani , Aaron D. Ludlow , Matteo Tomassetti

Motivated by the observed connection between molecular hydrogen (H2) and star formation, we present a method for tracking the non-equilibrium abundance and cooling processes of H2 and H2-based star formation in Smoothed Particle…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Charlotte Christensen , Thomas Quinn , Fabio Governato , Adrienne Stilp , Sijing Shen , James Wadsley

Galaxies in the early Universe were more compact and contained more molecular gas than today. In this paper, we revisit the relation between these empirical findings, and we quantitatively predict the cosmic evolution of the surface…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-09 Danail Obreschkow , Steve Rawlings

Due to the fact that HI mass measurements are not available for large galaxy samples at high redshifts, we apply a photometric estimator of the HI-to-stellar mass ratio (M_HI/M_*) calibrated using a local Universe sample of galaxies to a…

Astrophysics of Galaxies · Physics 2021-04-07 Wei Zhang , Guinevere Kauffmann , Jing Wang , Yanmei Chen , Jian Fu , Hong Wu

Modelling the distribution of neutral hydrogen (HI) in dark matter halos is important for studying galaxy evolution in the cosmological context. We use a novel approach to infer the HI-dark matter connection at the massive end ($m_{\rm HI}…

Astrophysics of Galaxies · Physics 2018-06-12 Niladri Paul , Tirthankar Roy Choudhury , Aseem Paranjape

We are conducting COLD GASS, a legacy survey for molecular gas in nearby galaxies. Using the IRAM 30m telescope, we measure the CO(1-0) line in a sample of ~350 nearby (D=100-200 Mpc), massive galaxies (log(M*/Msun)>10.0). The sample is…

We use a suite of hydrodynamics simulations of the interstellar medium (ISM) within a galactic disk, which include radiative transfer, a non-equilibrium model of molecular hydrogen, and a realistic model for star formation and feedback, to…

Astrophysics of Galaxies · Physics 2024-05-07 Ava Polzin , Andrey V. Kravtsov , Vadim A. Semenov , Nickolay Y. Gnedin

In this paper we present an attempt to estimate the redshift evolution of the molecular to neutral gas mass ratio within galaxies (at fixed stellar mass). For a sample of five nearby grand design spirals located on the Main Sequence (MS) of…

Astrophysics of Galaxies · Physics 2021-01-27 Laura Morselli , Alvio Renzini , Andrea Enia , Giulia Rodighiero

New and archival interferometric 12CO(1->0) datasets from six nearby galaxies are combined with H_2 2.122um and H-alpha maps to explore in detail the interstellar medium in different star-forming galaxies. We investigate the relation…

There is a robust polyatomic chemistry in diffuse, partially-molecular interstellar gas that is readily accessible in absorption at radio/mm/sub-mm wavelengths. Accurate column densities are derived owing to the weak internal excitation, so…

Astrophysics of Galaxies · Physics 2023-02-15 Harvey Liszt , Maryvonne Gerin

We use spectral stacking to measure the contribution of galaxies of different masses and in different hierarchies to the cosmic atomic hydrogen (HI) mass density in the local Universe. Our sample includes 1793 galaxies at $z < 0.11$…

We present 12CO (J=1-0) observations of a sample of local galaxies (0.04<z<0.08) with a large neutral hydrogen reservoir, or "HI monsters". The data were obtained using the Redshift Search Receiver on the FCRAO 14 m telescope. The sample…

Astrophysics of Galaxies · Physics 2015-06-19 Cheoljong Lee , Aeree Chung , Min S. Yun , Ryan Cybulski , G. Narayanan , N. Erickson

We compile and carrefully homogenize local galaxy samples with available information on stellar, $\rm HI$ and/or $\rm H_{2}$ masses, and morphology. After processing the information on upper limits in the case of non gas detections, we…

Robust knowledge of molecular gas mass is critical for understanding star formation in galaxies. The H$_{2}$ molecule does not emit efficiently in the cold interstellar medium, hence the molecular gas content of galaxies is typically…

Astrophysics of Galaxies · Physics 2016-10-12 Aditya Togi , J. D. T. Smith

We have recently developed a post-processing framework to estimate the abundance of atomic and molecular hydrogen (HI and H2, respectively) in galaxies in large-volume cosmological simulations. Here we compare the HI and H2 content of…

Empirical studies of the relationship between baryonic matter in galaxies and the gravitational potential of their host halos are important to constrain our theoretical framework for galaxy formation and evolution. One such relation,…

Astrophysics of Galaxies · Physics 2024-04-04 Manasvee Saraf , Luca Cortese , O. Ivy Wong , Barbara Catinella , Steven Janowiecki , Jennifer A. Hardwick