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Low-metallicity dwarf galaxies often show no or little CO emission, despite the intense star formation observed in local samples. Both simulations and resolved observations indicate that molecular gas in low-metallicity galaxies may reside…

The relation between the star formation rate and the kinetic energy increase in a region containing a large number of stellar sources is investigated as a possible prescription for star formation feedback in larger scale galaxy evolution…

Astrophysics · Physics 2009-10-31 John Scalo , David Chappell

We present a steady-state analytical model for pressure-regulated formation of molecular clouds (MC) and stars (SF) in gaseous galactic disks and apply it to the Milky Way (MW). MC formation depends on midplane interstellar pressure…

Astrophysics of Galaxies · Physics 2025-10-06 José Franco , Aldo Rodríguez-Puebla , Javier Ballesteros-Paredes , Manuel Zamora-Avilez

In regions where stars form, variations in density and temperature can cause gas to freeze-out onto dust grains forming ice mantles, which influences the chemical composition of a cloud. The aim of this paper is to understand in detail the…

Solar and Stellar Astrophysics · Physics 2017-11-08 S. Cazaux , R. Martin-Domenech , Y. J. Chen , G. M. Munoz Caro , C. Gonzalez Diaz

The conversion factor $\alpha_{\rm CO}$ from the observable CO(1-0) luminosity to the mass of molecular gas is known to vary between isolated galaxies and some mergers, but the underlying reasons are not clearly understood. Thus, the…

Astrophysics of Galaxies · Physics 2019-01-16 Florent Renaud , Frédéric Bournaud , Emanuele Daddi , Axel Weiß

Our understanding of how molecular clouds form in the interstellar medium (ISM) would be greatly helped if we had a reliable observational tracer of the gas flows responsible for forming the clouds. Fine structure emission from singly…

Astrophysics of Galaxies · Physics 2019-05-14 Paul C. Clark , Simon C. O. Glover , Sarah E. Ragan , Ana Duarte-Cabral

We combine the galaxy formation model GALFORM with the Photon Dominated Region code UCL_PDR to study the emission from the rotational transitions of 12CO (CO) in galaxies from z=0 to z=6 in the Lambda CDM framework. GALFORM is used to…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Claudia del P. Lagos , Estelle Bayet , Carlton M. Baugh , Cedric G. Lacey , Tom Bell , Nikolaos Fanidakis , James Geach

We explore the utility of CI as an alternative high-fidelity gas mass tracer for Galactic molecular clouds. We evaluate the X$_{\rm CI}$-factor for the 609 $\mu$m carbon line, the analog of the CO X-factor, which is the ratio of the H$_2$…

Solar and Stellar Astrophysics · Physics 2014-03-05 Stella S. R. Offner , Thomas G. Bisbas , Tom A. Bell , Serena Viti

In the Local Group spiral galaxy M33, we investigate the correlation between the star formation rate (SFR) surface density, Sigma_SFR, and the gas density Sigma_gas (molecular, atomic, and total). We also explore whether there are other…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 S. Verley , E. Corbelli , C. Giovanardi , L. K. Hunt

We study the formation of giant dense cloud complexes and of stars within them by means of SPH numerical simulations of the mildly supersonic collision of gas streams (``inflows'') in the warm neutral medium (WNM). The resulting…

The CO-to-H$_2$ conversion factor ($\alpha_\rm{CO}$) is critical to studying molecular gas and star formation in galaxies. The value of $\alpha_\rm{CO}$ has been found to vary within and between galaxies, but the specific environmental…

We run numerical simulations of molecular clouds (MCs), adopting properties similar to those found in the Central Molecular Zone (CMZ) of the Milky Way. For this, we employ the moving mesh code Arepo and perform simulations which account…

Astrophysics of Galaxies · Physics 2016-09-21 Erik Bertram , Simon C. O. Glover , Paul C. Clark , Sarah E. Ragan , Ralf S. Klessen

In this study, we explored the impact of isolated and group environments on stellar mass, star formation rate (SFR), and specific star formation rate (SSFR, i.e., the rate of star formation per unit stellar mass) using the galaxy dataset…

Astrophysics of Galaxies · Physics 2025-04-17 Pius Privatus , Umananda Dev Goswami

Radiation feedback from stellar clusters is expected to play a key role in setting the rate and efficiency of star formation in giant molecular clouds (GMCs). To investigate how radiation forces influence realistic turbulent systems, we…

Astrophysics of Galaxies · Physics 2016-10-05 Sudhir Raskutti , Eve C. Ostriker , M. Aaron Skinner

We propose a simple theoretical model for star formation in which the local star formation rate in a galaxy is determined by three factors. First, the interplay between the interstellar radiation field and molecular self-shielding…

Astrophysics of Galaxies · Physics 2011-02-11 Mark R. Krumholz , Christopher F. McKee , Jason Tumlinson

We present spectra of the extended 12CO and 13CO J=1-0 emission along the major axes of 17 nearby galaxies. Spatial variations in the ratio of CO and 13CO integrated intensities, R, are found in nearly every galaxy observed. There is an…

Ultraviolet (UV) photodissociation of CO controls the abundances and distribution of CO and its photodissociation products. This significantly influences the gas-phase chemistry in the circumstellar envelope (CSE) around evolved stars. A…

Solar and Stellar Astrophysics · Physics 2019-05-22 Maryam Saberi , Wouter Vlemmings , Elvire De Beck

In an effort to understand the factors that govern the transition from low- to high-mass star formation, we identify for the first time a sample of intermediate-mass star-forming regions (IM SFRs) where stars up to - but not exceeding - 8…

Astrophysics of Galaxies · Physics 2015-05-19 Kim Arvidsson , Charles R. Kerton , Michael J. Alexander , Henry A. Kobulnicky , Brian Uzpen

There are two major theoretical issues for the star formation law (the relation between the surface densities of molecular gas and star formation rate on a galaxy scale): (i) At low metallicity, it is not obvious that star-forming regions…

Astrophysics of Galaxies · Physics 2018-01-24 Li-Hsin Chen , Hiroyuki Hirashita , Kuan-Chou Hou , Shohei Aoyama , Ikkoh Shimizu , Kentaro Nagamine

We investigated the correlation between intensities of the $^{12}$CO and $^{13}$CO ($J=1$-0) lines toward the Galactic giant molecular clouds (GMCs) W51A, W33, N35-N36 complex, W49A, M17SW, G12.02-00.03, W43, and M16 using the FUGIN (FOREST…

Astrophysics of Galaxies · Physics 2023-11-27 Mikito Kohno , Yoshiaki Sofue