Dense gas scaling relations at kiloparsec scales across nearby galaxies with the ALMA ALMOND and IRAM 30 m EMPIRE surveys

Dense, cold gas is the key ingredient for star formation. Over the last two decades, HCN(1 − 0) emission has been the most accessible dense gas tracer for studying external galaxies. We present new measurements that demonstrate the relationship between dense gas tracers, bulk molecular gas tracers, and star formation in the ALMA ALMOND survey, the largest sample of resolved (1–2 kpc resolution) HCN maps of galaxies in the local Universe ( d < 25 Mpc). We measured HCN/CO, a line ratio sensitive to the physical density distribution, and the star formation rate to HCN ratio (SFR/HCN), a proxy for the dense gas star formation efficiency, as a function of molecular gas surface density, stellar mass surface density, and dynamical equilibrium pressure across 31 galaxies (a factor of > 3 more compared to the previously largest such study, EMPIRE). HCN/CO increases (slope of ≈0.5 and scatter of ≈0.2 dex) and SFR/HCN decreases (slope of ≈ − 0.6 and scatter of ≈0.4 dex) with increasing molecular gas surface density, stellar mass surface density, and pressure. Galaxy centres with high stellar mass surface densities show a factor of a few higher HCN/CO and lower SFR/HCN compared to the disc average, but the two environments follow the same average trend. Our results emphasise that molecular gas properties vary systematically with the galactic environment and demonstrate that the scatter in the Gao–Solomon relation (SFR/HCN) has a physical origin.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2024-12-24
DOI
https://doi.org/10.1051/0004-6361/202453208
Citations
3
Primary Topic
Astrophysics and Star Formation Studies
Type
article
Field-Weighted Citation Impact
0.99

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article

Dense gas scaling relations at kiloparsec scales across nearby galaxies with the ALMA ALMOND and IRAM 30 m EMPIRE surveys

Sophia K. Stuber, Miguel Querejeta, Lukas Neumann, Hao He et al.
3 citations
Astronomy and Astrophysics
Astrophysics and Star Formation Studies
0.99
article

Dense gas scaling relations at kiloparsec scales across nearby galaxies with the ALMA ALMOND and IRAM 30 m EMPIRE surveys

Sophia K. Stuber, Miguel Querejeta, Lukas Neumann, Hao He, Ashley T. Barnes, Frank Bigiel, Thomas G. Williams, Eva Schinnerer, Jiayi Sun, Cosima Eibensteiner, Ralf S. Klessen, Adam K. Leroy, Fu-Heng Liang, María J. Jiménez-Donaire, A. Usero, Hsi-An Pan, Daizhong Liu, Yixian Cao, Jakob den Brok, Ivana Bešlić
article en
3 citations

Abstract

Dense, cold gas is the key ingredient for star formation. Over the last two decades, HCN(1 − 0) emission has been the most accessible dense gas tracer for studying external galaxies. We present new measurements that demonstrate the relationship between dense gas tracers, bulk molecular gas tracers, and star formation in the ALMA ALMOND survey, the largest sample of resolved (1–2 kpc resolution) HCN maps of galaxies in the local Universe ( d < 25 Mpc). We measured HCN/CO, a line ratio sensitive to the physical density distribution, and the star formation rate to HCN ratio (SFR/HCN), a proxy for the dense gas star formation efficiency, as a function of molecular gas surface density, stellar mass surface density, and dynamical equilibrium pressure across 31 galaxies (a factor of > 3 more compared to the previously largest such study, EMPIRE). HCN/CO increases (slope of ≈0.5 and scatter of ≈0.2 dex) and SFR/HCN decreases (slope of ≈ − 0.6 and scatter of ≈0.4 dex) with increasing molecular gas surface density, stellar mass surface density, and pressure. Galaxy centres with high stellar mass surface densities show a factor of a few higher HCN/CO and lower SFR/HCN compared to the disc average, but the two environments follow the same average trend. Our results emphasise that molecular gas properties vary systematically with the galactic environment and demonstrate that the scatter in the Gao–Solomon relation (SFR/HCN) has a physical origin.

Astronomy and AstrophysicsVol. 693
Tamkang University (TW), Centre National de la Recherche Scientifique (FR), University of Bonn (DE), Princeton University (US), Heidelberg University (DE), National Radio Astronomy Observatory (US), Université Paris Sciences et Lettres (FR), Purple Mountain Observatory (CN), Sorbonne Université (FR), University of Oxford (GB), Max Planck Institute for Extraterrestrial Physics (DE), Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères (FR), Max Planck Institute for Astronomy (DE), Center for Southeast Asian Studies (FR), Yebes Observatory (ES), Forschungsstätte der Evangelischen Studiengemeinschaft (DE), Center for Astrophysics Harvard & Smithsonian (US), European Southern Observatory (CL), Spanish National Observatory (ES), The Ohio State University (US)
National Science Foundation, National Aeronautics and Space Administration, Alexander von Humboldt-Stiftung, California Institute of Technology, National Radio Astronomy Observatory, Deutsche Forschungsgemeinschaft, National Science Council, Centre National d’Etudes Spatiales, Korea Astronomy and Space Science Institute, National Astronomical Observatory of Japan, National Science and Technology Council, European Research Council, National Institutes of Natural Sciences, European Regional Development Fund, Agencia Estatal de Investigación
Openalex Percentile: Top 22%
Astrophysics and Star Formation Studies
0.99
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