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Related papers: The atomic-to-molecular hydrogen transition in the…

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Observations of intergalactic neutral hydrogen can provide a wealth of information about structure and galaxy formation, potentially tracing accretion and feedback processes on Mpc scales. Below a column density of NHI ~ 10^19 cm-2, the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Attila Popping , Romeel Dave , Robert Braun , Benjamin D. Oppenheimer

We present new analytic theory and radiative transfer computations for the atomic to molecular (HI-to-H2) transitions, and the build-up of atomic-hydrogen (HI) gas columns, in optically thick interstellar clouds, irradiated by…

Astrophysics of Galaxies · Physics 2015-06-19 Amiel Sternberg , Franck Le Petit , Evelyne Roueff , Jacques Le Bourlot

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

We have investigated the time scale for formation of molecular clouds by examining the conversion of HI to H2 using a time-dependent model. H2 formation on dust grains and cosmic ray and photo destruction are included in one-dimensional…

Astrophysics · Physics 2008-11-26 Paul F. Goldsmith , Di Li , Marko Krco

We contrast the gas kinematics and dark matter contents of $z=2$ star-forming galaxies (SFGs) from state-of-the-art cosmological simulations within the $\Lambda$CDM framework to observations. To this end, we create realistic mock…

Aims. We present a new sub-grid model, HYACINTH -- HYdrogen And Carbon chemistry in the INTerstellar medium in Hydro simulations -- for computing the non-equilibrium abundances of ${\rm H_2}$ and its carbon-based tracers, namely ${\rm CO}$,…

Astrophysics of Galaxies · Physics 2024-07-02 Prachi Khatri , Cristiano Porciani , Emilio Romano-Díaz , Daniel Seifried , Alexander Schäbe

We present the new TNG50 cosmological, magnetohydrodynamical simulation -- the third and final volume of the IllustrisTNG project. This simulation occupies a unique combination of large volume and high resolution, with a 50 Mpc box sampled…

We present a comparison of galaxy atomic and molecular gas properties in three recent cosmological hydrodynamic simulations, Simba, EAGLE, and Illustris-TNG, versus observations from $z\sim 0-2$. These simulations all rely on similar…

The presence of atomic gas mixed with molecular species in a "molecular" cloud may significantly affect its chemistry, the excitation of some species, and can serve as probe of the cloud's evolution. Cold neutral atomic hydrogen (HI) in…

Astrophysics · Physics 2009-11-13 Marko Krco , Paul F. Goldsmith , Robert L. Brown , Di Li

We present a novel framework to self-consistently model the effects of radiation fields, dust physics and molecular chemistry (H$_2$) in the interstellar medium (ISM) of galaxies. The model combines a state-of-the-art radiation…

Using a simple model of photodissociated atomic hydrogen on a galactic scale, it is possible to derive total hydrogen volume densities. These densities, obtained through a combination of atomic hydrogen, far-ultraviolet and metallicity…

Astrophysics of Galaxies · Physics 2015-06-11 J. S. Heiner , J. R. Sánchez-Gallego , L. Rousseau-Nepton , J. H. Knapen

We present a detailed description of a phenomenological H2 formation model and local star formation prescription based on the density of molecular (rather than total) gas. Such approach allows us to avoid the arbitrary density and…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-28 Nickolay Y. Gnedin , Andrey V. Kravtsov

We apply novel survival analysis techniques to investigate the relationship between a number of the properties of galaxies and their atomic ($M_\mathrm{HI}$) and molecular ($M_{\mathrm{H_2}}$) gas mass, with the aim of devising efficient,…

Astrophysics of Galaxies · Physics 2019-11-06 Hassen M. Yesuf , Luis C. Ho

Upcoming 21cm surveys will map the spatial distribution of cosmic neutral hydrogen (HI) over unprecedented volumes. Mock catalogues are needed to fully exploit the potential of these surveys. Standard techniques employed to create these…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-02 Digvijay Wadekar , Francisco Villaescusa-Navarro , Shirley Ho , Laurence Perreault-Levasseur

We introduce the new TNG-Cluster project, an addition to the IllustrisTNG suite of cosmological magnetohydrodynamical simulations of galaxy formation. Our objective is to significantly increase the statistical sampling of the most massive…

Astrophysics of Galaxies · Physics 2024-03-08 Dylan Nelson , Annalisa Pillepich , Mohammadreza Ayromlou , Wonki Lee , Katrin Lehle , Eric Rohr , Nhut Truong

Low-ionization metal absorption lines provide a primary probe of cool gas in and around galaxies. We confront observations of metal-line absorption in quasar spectra with predictions from the IllustrisTNG cosmological simulation in order to…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-17 Ivan Rapoport , Ehud Behar , Vincent Desjacques

We present numerical computations and analysis of atomic to molecular (HI-to-H$_2$) transitions in cool ($\sim$100 K) low-metallicity dust-free (primordial) gas, in which molecule formation occurs via cosmic-ray driven negative ion…

Astrophysics of Galaxies · Physics 2021-10-27 Amiel Sternberg , Alon Gurman , Shmuel Bialy

We present the detection analysis of a diffuse molecular cloud at z$_{abs}$=2.4636 towards the quasar SDSS J1513+0352(z$_{em}\,\simeq$ 2.68) observed with the X-shooter spectrograph(VLT). We measure very high column densities of atomic and…

We use the IllustrisTNG100 hydrodynamical simulation to study the dependence of the galaxy two-point correlation function on a broad range of secondary subhalo and galactic properties. We construct galaxy mock catalogues adopting a standard…

Astrophysics of Galaxies · Physics 2021-11-04 Ginevra Favole , Antonio D. Montero-Dorta , M. Celeste Artale , Sergio Contreras , Idit Zehavi , Xiaoju Xu

Recent observations indicate that star formation occurs only in the molecular phase of a galaxy's interstellar medium. A realistic treatment of star formation in simulations and analytic models of galaxies therefore requires that one…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Mark R. Krumholz , Nickolay Y. Gnedin