TY - JOUR
T1 - Dynamical Equilibrium in the Molecular ISM in 28 Nearby Star-forming Galaxies
AU - Sun, Jiayi
AU - Leroy, Adam K.
AU - Ostriker, Eve C.
AU - Hughes, Annie
AU - Rosolowsky, Erik
AU - Schruba, Andreas
AU - Schinnerer, Eva
AU - Blanc, Guillermo A.
AU - Faesi, Christopher
AU - Kruijssen, J. M.Diederik
AU - Meidt, Sharon
AU - Utomo, Dyas
AU - Bigiel, Frank
AU - Bolatto, Alberto D.
AU - Chevance, Mélanie
AU - Chiang, I. Da
AU - Dale, Daniel
AU - Emsellem, Eric
AU - Glover, Simon C.O.
AU - Grasha, Kathryn
AU - Henshaw, Jonathan
AU - Herrera, Cinthya N.
AU - Jimenez-Donaire, Maria Jesus
AU - Lee, Janice C.
AU - Pety, Jérôme
AU - Querejeta, Miguel
AU - Saito, Toshiki
AU - Sandstrom, Karin
AU - Usero, Antonio
N1 - Publisher Copyright:
© 2020 The American Astronomical Society.
PY - 2020/4/1
Y1 - 2020/4/1
N2 - We compare the observed turbulent pressure in molecular gas, P turb, to the required pressure for the interstellar gas to stay in equilibrium in the gravitational potential of a galaxy, P DE. To do this, we combine arcsecond resolution CO data from PHANGS-ALMA with multiwavelength data that trace the atomic gas, stellar structure, and star formation rate (SFR) for 28 nearby star-forming galaxies. We find that P turb correlates with-but almost always exceeds-the estimated P DE on kiloparsec scales. This indicates that the molecular gas is overpressurized relative to the large-scale environment. We show that this overpressurization can be explained by the clumpy nature of molecular gas; a revised estimate of P DE on cloud scales, which accounts for molecular gas self-gravity, external gravity, and ambient pressure, agrees well with the observed P turb in galaxy disks. We also find that molecular gas with cloud-scale Pturb ≈ PDE 10 × 5, k_BK cm-3 in our sample is more likely to be self-gravitating, whereas gas at lower pressure it appears more influenced by ambient pressure and/or external gravity. Furthermore, we show that the ratio between P turb and the observed SFR surface density, Σ SFR, is compatible with stellar feedback-driven momentum injection in most cases, while a subset of the regions may show evidence of turbulence driven by additional sources. The correlation between Σ SFR and kpc-scale P DE in galaxy disks is consistent with the expectation from self-regulated star formation models. Finally, we confirm the empirical correlation between molecular-to-atomic gas ratio and kpc-scale P DE reported in previous works.
AB - We compare the observed turbulent pressure in molecular gas, P turb, to the required pressure for the interstellar gas to stay in equilibrium in the gravitational potential of a galaxy, P DE. To do this, we combine arcsecond resolution CO data from PHANGS-ALMA with multiwavelength data that trace the atomic gas, stellar structure, and star formation rate (SFR) for 28 nearby star-forming galaxies. We find that P turb correlates with-but almost always exceeds-the estimated P DE on kiloparsec scales. This indicates that the molecular gas is overpressurized relative to the large-scale environment. We show that this overpressurization can be explained by the clumpy nature of molecular gas; a revised estimate of P DE on cloud scales, which accounts for molecular gas self-gravity, external gravity, and ambient pressure, agrees well with the observed P turb in galaxy disks. We also find that molecular gas with cloud-scale Pturb ≈ PDE 10 × 5, k_BK cm-3 in our sample is more likely to be self-gravitating, whereas gas at lower pressure it appears more influenced by ambient pressure and/or external gravity. Furthermore, we show that the ratio between P turb and the observed SFR surface density, Σ SFR, is compatible with stellar feedback-driven momentum injection in most cases, while a subset of the regions may show evidence of turbulence driven by additional sources. The correlation between Σ SFR and kpc-scale P DE in galaxy disks is consistent with the expectation from self-regulated star formation models. Finally, we confirm the empirical correlation between molecular-to-atomic gas ratio and kpc-scale P DE reported in previous works.
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U2 - 10.3847/1538-4357/ab781c
DO - 10.3847/1538-4357/ab781c
M3 - Article
AN - SCOPUS:85083987261
SN - 0004-637X
VL - 892
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 148
ER -