THE RELATIONSHIP BETWEEN MOLECULAR GAS, H i, AND STAR FORMATION IN THE LOW-MASS, LOW-METALLICITY MAGELLANIC CLOUDS
Year: 2016
Type: article
Abstract: ABSTRACT The Magellanic Clouds provide the only laboratory to study the effects of metallicity and galaxy mass on molecular gas and star formation at high (∼⃒20 pc) resolution. We use the dust emission from HERITAGE Herschel data to map the molecular gas in the Magellanic Clouds, avoiding the known biases of CO emission as a tracer of H 2 . Using our dust-based molecular gas estimates, we find molecular gas depletion times ( τ dep mol ) of ∼⃒0.4 Gyr in the Large Magellanic Cloud and ∼⃒0.6 in the Small Magellanic Cloud at 1 kpc scales. These depletion times fall within the range found for normal disk galaxies, but are shorter than the average value, which could be due to recent bursts in star formation. We find no evidence for a strong intrinsic dependence of the molecular gas depletion time on metallicity. We study the relationship between the gas and the star formation rate across a range of size scales from 20 pc to ≧̸1 kpc, including how the scatter in τ dep mol changes with the size scale, and discuss the physical mechanisms driving the relationships. We compare the metallicity-dependent star formation models of Ostriker et al. and Krumholz to our observations and find that they both predict the trend in the data, suggesting that the inclusion of a diffuse neutral medium is important at lower metallicity.
Source: The Astrophysical Journal
Authors: Katherine E. Jameson, Alberto D. Bolatto, Adam K. Leroy, Margaret Meixner, Julia Roman-Duval, Karl Gordon, Annie Hughes, Frank P. Israel, Monica Rubio, Remy Indebetouw, Suzanne C. Madden, Caroline Bot, Sacha Hony, Diane Cormier, Eric W. Pellegrini, Maud Galametz, George Sonneborn
Institutions: University of Maryland, College Park, The Ohio State University, Space Telescope Science Institute, Max Planck Institute for Astronomy, Leiden University, Leiden Observatory, University of Chile, National Radio Astronomy Observatory, University of Virginia, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Astrophysique, Instrumentation et Modélisation, Institut de Recherche sur les Lois Fondamentales de l'Univers, Centre National de la Recherche Scientifique, Observatoire astronomique de Strasbourg, Université de Strasbourg, Heidelberg University, University of Toledo, European Southern Observatory, Goddard Space Flight Center
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2258104773