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Dynamical Equilibrium in the Molecular ISM in 28 Nearby Star-forming Galaxies

Sun, Jiayi and Leroy, Adam K. and Ostriker, Eve C. and Hughes, Annie and Rosolowsky, Erik and Schruba, Andreas and Schinnerer, Eva and Blanc, Guillermo A. and Faesi, Christopher and Kruijssen, J. M. Diederik and Meidt, Sharon and Utomo, Dyas and Bigiel, Frank and Bolatto, Alberto D. and Chevance, Mélanie and Chiang, I-Da and Dale, Daniel and Emsellem, Eric and Glover, Simon C. O. and Grasha, Kathryn and Henshaw, Jonathan and Herrera, Cinthya N. and Jimenez-Donaire, Maria Jesus and Lee, Janice C. and Pety, Jérôme and Querejeta, Miguel and Saito, Toshiki and Sandstrom, Karin and Usero, Antonio (2020) Dynamical Equilibrium in the Molecular ISM in 28 Nearby Star-forming Galaxies. Astrophysical Journal, 892 (2). Art. No. 148. ISSN 1538-4357.

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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 P_(turb) ≈ P_(DE) ≳ 10⁵ kB K 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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Sun, Jiayi0000-0003-0378-4667
Leroy, Adam K.0000-0002-2545-1700
Ostriker, Eve C.0000-0002-0509-9113
Hughes, Annie0000-0002-9181-1161
Rosolowsky, Erik0000-0002-5204-2259
Schinnerer, Eva0000-0002-3933-7677
Blanc, Guillermo A.0000-0003-4218-3944
Faesi, Christopher0000-0001-5310-467X
Kruijssen, J. M. Diederik0000-0002-8804-0212
Meidt, Sharon0000-0002-6118-4048
Utomo, Dyas0000-0003-4161-2639
Bigiel, Frank0000-0003-0166-9745
Bolatto, Alberto D.0000-0002-5480-5686
Chevance, Mélanie0000-0002-5635-5180
Chiang, I-Da0000-0003-2551-7148
Dale, Daniel0000-0002-5782-9093
Emsellem, Eric0000-0002-6155-7166
Glover, Simon C. O.0000-0001-6708-1317
Grasha, Kathryn0000-0002-3247-5321
Henshaw, Jonathan0000-0001-9656-7682
Jimenez-Donaire, Maria Jesus0000-0002-9165-8080
Lee, Janice C.0000-0002-2278-9407
Pety, Jérôme0000-0003-3061-6546
Querejeta, Miguel0000-0002-0472-1011
Saito, Toshiki0000-0002-2501-9328
Sandstrom, Karin0000-0002-4378-8534
Usero, Antonio0000-0003-1242-505X
Additional Information:© 2020 The American Astronomical Society. Received 2019 November 18; revised 2020 January 18; accepted 2020 February 14; published 2020 April 7. We thank the anonymous referee for helpful comments that improved the quality of the paper. J.S. would like to thank R. Herrera-Camus and C. Murugeshan for kindly sharing their data, as well as D. Fisher and T. A. Thompson for helpful discussions. This work was carried out as part of the PHANGS collaboration. The work of J.S., A.K.L., and D.U. is partially supported by the National Science Foundation (NSF) under Grants No. 1615105, 1615109, and 1653300. The work of J.S. and A.K.L. is partially supported by NASA under ADAP grants NNX16AF48G and NNX17AF39G. The work of E.C.O. is partly supported by NASA under ATP grant NNX17AG26G. A.H., C.N.H., and J.P. acknowledge funding from the Programme National "Physique et Chimie du Milieu Interstellaire (PCMI)" of CNRS/INSU with INC/INP, co-funded by CEA and CNES, and from the "Programme National Cosmology et Galaxies (PNCG)" of CNRS/INSU with INP and IN2P3, co-funded by CEA and CNES. E.R. acknowledges the support of the Natural Sciences and Engineering Research Council of Canada (NSERC), funding reference number RGPIN-2017-03987. E.S., C.F., and T.S. acknowledges funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No. 694343). J.M.D.K. and M.C. gratefully acknowledge funding from the Deutsche Forschungsgemeinschaft (DFG) through an Emmy Noether Research Group (grant No. KR4801/1-1) and the DFG Sachbeihilfe (grant No. KR4801/2-1). J.M.D.K. gratefully acknowledges funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme via the ERC Starting Grant MUSTANG (grant agreement No. 714907). F.B. acknowledges funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No. 726384). S.C.O.G. acknowledges support by the Deutsche Forschungsgemeinschaft (DFG; German Research Foundation)—Project-ID 138713538—SFB 881 ("The Milky Way System," subprojects B01, B02, B08), and by the Heidelberg cluster of excellence EXC 2181-390900948 "STRUCTURES: A unifying approach to emergent phenomena in the physical world, mathematics, and complex data," funded by the German Excellence Strategy. A.U. acknowledges support from the Spanish funding grants AYA2016-79006-P (MINECO/FEDER) and PGC2018-094671-B-I00 (MCIU/AEI/FEDER). This paper makes use of the following ALMA data: ADS/JAO.ALMA# 2012.1.00650.S, 2015.1.00925.S, 2015.1.00956.S, 2017.1.00392.S, 2017.1.00886.L, and 2018.1.01321.S. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This work is based in part on observations made with NSF's Karl G. Jansky Very Large Array (Legacy ID: AS 1303, AS1387, AS1434, AU157). VLA is also operated by the National Radio Astronomy Observatory. This work is based in part on observations made with the Australia Telescope Compact Array (ATCA). ATCA is part of the Australia Telescope National Facility, which is funded by the Australian Government for operation as a National Facility managed by CSIRO. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. This work is based in part on observations made with the Galaxy Evolution Explorer (GALEX). GALEX is a NASA Small Explorer, whose mission was developed in cooperation with the Centre National d'Etudes Spatiales (CNES) of France and the Korean Ministry of Science and Technology. GALEX is operated for NASA by the California Institute of Technology under NASA contract NAS5-98034. This publication makes use of data products from the Wide-field Infrared Survey Explorer (WISE), which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. We acknowledge the usage of the Extragalactic Distance Database35 (Tully et al. 2009), the HyperLeda database36 (Makarov et al. 2014), the NASA/IPAC Extragalactic Database,37 and the SAO/NASA Astrophysics Data System.38 Facilities: ALMA - Atacama Large Millimeter Array, VLA - , ATCA - , Spitzer - , WISE - , GALEX. - Software: CASA (McMullin et al. 2007), Astropy (Astropy Collaboration et al. 2013, 2018).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Institut National des Sciences de l'Univers (INSU)UNSPECIFIED
Commissariat à l’Energie Atomique (CEA)UNSPECIFIED
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Institut National de Physique Nucléaire et de Physique des Particules (IN2P3)UNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)RGPIN-2017-03987
European Research Council (ERC)694343
Deutsche Forschungsgemeinschaft (DFG)KR4801/1-1
Deutsche Forschungsgemeinschaft (DFG)KR4801/2-1
European Research Council (ERC)714907
European Research Council (ERC)726384
Deutsche Forschungsgemeinschaft (DFG)138713538
Deutsche Forschungsgemeinschaft (DFG)SFB 881
Heidelberg Cluster of Excellence2181-390900948
German Universities Excellence InitiativeUNSPECIFIED
Ministerio de Economía, Industria y Competitividad (MINECO)AYA2016-79006-P
Ministerio de Economía, Industria y Competitividad (MINECO)PGC2018-094671-B-I00
Fondo Europeo de Desarrollo Regional (FEDER)UNSPECIFIED
Australian GovernmentUNSPECIFIED
Subject Keywords:Interstellar molecules ; Star formation ; Interstellar dynamics
Issue or Number:2
Record Number:CaltechAUTHORS:20200408-083529159
Persistent URL:
Official Citation:Jiayi Sun et al 2020 ApJ 892 148
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:102394
Deposited By: Tony Diaz
Deposited On:08 Apr 2020 17:01
Last Modified:09 Apr 2020 22:53

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