Dense Gas, Dynamical Equilibrium Pressure, and Star Formation in Nearby Star-forming Galaxies
Year: 2018
Type: article
Abstract: We use new ALMA observations to investigate the connection between dense gas fraction, star formation rate (SFR), and local environment across the inner region of four local galaxies showing a wide range of molecular gas depletion times. We map HCN (1–0), HCO+ (1–0), CS (2–1), 13CO (1–0), and C18O (1–0) across the inner few kiloparsecs of each target. We combine these data with short-spacing information from the IRAM large program EMPIRE, archival CO maps, tracers of stellar structure and recent star formation, and recent HCN surveys by Bigiel et al. and Usero et al. We test the degree to which changes in the dense gas fraction drive changes in the SFR. (tracing the dense gas fraction) correlates strongly with I CO (tracing molecular gas surface density), stellar surface density, and dynamical equilibrium pressure, P DE. Therefore, becomes very low and HCN becomes very faint at large galactocentric radii, where ratios as low as become common. The apparent ability of dense gas to form stars, (where Σdense is traced by the HCN intensity and the star formation rate is traced by a combination of Hα and 24 μm emission), also depends on environment. decreases in regions of high gas surface density, high stellar surface density, and high P DE. Statistically, these correlations between environment and both and are stronger than that between apparent dense gas fraction ( ) and the apparent molecular gas star formation efficiency . We show that these results are not specific to HCN.
Source: The Astrophysical Journal
Authors: Molly J. Gallagher, Adam K. Leroy, Frank Bigiel, Diane Cormier, María J. Jiménez-Donaire, Eve Ostriker, Antonio Usero, Alberto D. Bolatto, Santiago García-Burillo, Annie Hughes, Amanda A. Kepley, Mark Krumholz, Sharon E. Meidt, David S. Meier, Eric J. Murphy, Jérôme Pety, Erik Rosolowsky, Eva Schinnerer, Andreas Schruba, Fabian Walter
Institutions: The Ohio State University, Heidelberg University, Centre National de la Recherche Scientifique, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Astrophysique, Instrumentation et Modélisation, CEA Paris-Saclay, Université Paris Diderot, Princeton University, Spanish National Observatory, Joint Space Science Institute, University of Maryland, College Park, Université Toulouse III - Paul Sabatier, Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, National Radio Astronomy Observatory, Australian National University, Max Planck Institute for Astronomy, New Mexico Institute of Mining and Technology, Observatoire de Paris, Institut de Radioastronomie Millimétrique, University of Alberta, Max Planck Institute for Extraterrestrial Physics
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, National Aeronautics and Space Administration, National Radio Astronomy Observatory, European Commission, Deutsche Forschungsgemeinschaft, National Science Council, Centre National d’Etudes Spatiales, Korea Astronomy and Space Science Institute, Max-Planck-Gesellschaft, Centre National de la Recherche Scientifique, National Astronomical Observatory of Japan, Natural Sciences and Engineering Research Council of Canada, National Institutes of Natural Sciences
Awards: Collaborative Research: The Origin and Role of Dense Molecular Gas in Star-Forming Galaxies, G2800009104, G3207356259, The Role of Gas in the Evolution of Galaxies, G393177772, Collaborative Research: Dust, Gas, and Star Formation: Synthesizing 20 Years of Radio, Millimeter, and Infrared Surveys, G4104599821, G4760961572, CAREER: Observing the Physics of Star Formation in Galaxies, G5702163051, Detailed Anatomy of Galaxies, G7390005016, Characterizing properties of the interstellar medium to better understand how stars form in galaxies
OpenAlex ID: W2794648399