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Molecular Gas Properties on Cloud Scales across the Local Star-forming Galaxy Population

Sun, Jiayi and Leroy, Adam K. and Schinnerer, Eva and Hughes, Annie and Rosolowsky, Erik and Querejeta, Miguel and Schruba, Andreas and Liu, Daizhong and Saito, Toshiki and Herrera, Cinthya N. and Faesi, Christopher and Usero, Antonio and Pety, Jérôme and Kruijssen, J. M. Diederik and Ostriker, Eve C. and Bigiel, Frank and Blanc, Guillermo A. and Bolatto, Alberto D. and Boquien, Médéric and Chevance, Mélanie and Dale, Daniel A. and Deger, Sinan and Emsellem, Eric and Glover, Simon C. O. and Grasha, Kathryn and Groves, Brent and Henshaw, Jonathan and Jimenez-Donaire, Maria J. and Kim, Jenny J. and Klessen, Ralf S. and Kreckel, Kathryn and Lee, Janice C. and Meidt, Sharon and Sandstrom, Karin and Sardone, Amy E. and Utomo, Dyas and Williams, Thomas G. (2020) Molecular Gas Properties on Cloud Scales across the Local Star-forming Galaxy Population. Astrophysical Journal Letters, 901 (1). Art. No. L8. ISSN 2041-8213.

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Using the PHANGS–ALMA CO(2–1) survey, we characterize molecular gas properties on ~100 pc scales across 102,778 independent sightlines in 70 nearby galaxies. This yields the best synthetic view of molecular gas properties on cloud scales across the local star-forming galaxy population obtained to date. Consistent with previous studies, we observe a wide range of molecular gas surface densities (3.4 dex), velocity dispersions (1.7 dex), and turbulent pressures (6.5 dex) across the galaxies in our sample. Under simplifying assumptions about subresolution gas structure, the inferred virial parameters suggest that the kinetic energy of the molecular gas typically exceeds its self-gravitational binding energy at ~100 pc scales by a modest factor (1.3 on average). We find that the cloud-scale surface density, velocity dispersion, and turbulent pressure (1) increase toward the inner parts of galaxies, (2) are exceptionally high in the centers of barred galaxies (where the gas also appears less gravitationally bound), and (3) are moderately higher in spiral arms than in inter-arm regions. The galaxy-wide averages of these gas properties also correlate with the integrated stellar mass, star formation rate, and offset from the star-forming main sequence of the host galaxies. These correlations persist even when we exclude regions with extraordinary gas properties in galaxy centers, which contribute significantly to the inter-galaxy variations. Our results provide key empirical constraints on the physical link between molecular cloud populations and their galactic environment.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Sun, Jiayi0000-0003-0378-4667
Leroy, Adam K.0000-0002-2545-1700
Schinnerer, Eva0000-0002-3933-7677
Hughes, Annie0000-0002-9181-1161
Rosolowsky, Erik0000-0002-5204-2259
Querejeta, Miguel0000-0002-0472-1011
Liu, Daizhong0000-0001-9773-7479
Saito, Toshiki0000-0002-2501-9328
Herrera, Cinthya N.0000-0001-6405-0785
Faesi, Christopher0000-0001-5310-467X
Usero, Antonio0000-0003-1242-505X
Pety, Jérôme0000-0003-3061-6546
Kruijssen, J. M. Diederik0000-0002-8804-0212
Ostriker, Eve C.0000-0002-0509-9113
Bigiel, Frank0000-0003-0166-9745
Blanc, Guillermo A.0000-0003-4218-3944
Bolatto, Alberto D.0000-0002-5480-5686
Boquien, Médéric0000-0003-0946-6176
Chevance, Mélanie0000-0002-5635-5180
Dale, Daniel A.0000-0002-5782-9093
Deger, Sinan0000-0003-1943-723X
Emsellem, Eric0000-0002-6155-7166
Glover, Simon C. O.0000-0001-6708-1317
Grasha, Kathryn0000-0002-3247-5321
Groves, Brent0000-0002-9768-0246
Henshaw, Jonathan0000-0001-9656-7682
Jimenez-Donaire, Maria J.0000-0002-9165-8080
Kim, Jenny J.0000-0002-0432-6847
Klessen, Ralf S.0000-0002-0560-3172
Kreckel, Kathryn0000-0001-6551-3091
Lee, Janice C.0000-0002-2278-9407
Meidt, Sharon0000-0002-6118-4048
Sandstrom, Karin0000-0002-4378-8534
Sardone, Amy E.0000-0002-5783-145X
Utomo, Dyas0000-0003-4161-2639
Williams, Thomas G.0000-0002-0012-2142
Additional Information:© 2020 The American Astronomical Society. Received 2020 July 25; revised 2020 August 25; accepted 2020 August 27; published 2020 September 18. 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 grant Nos. 1615105, 1615109, and 1653300, as well as by the National Aeronautics and Space Administration (NASA) under ADAP grants NNX16AF48G and NNX17AF39G. E.S., D.L., T.S., and T.G.W. acknowledge funding from the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation program (grant agreement No. 694343). E.R. acknowledges the support of the Natural Sciences and Engineering Research Council of Canada (NSERC), funding reference number RGPIN-2017-03987. A.U. acknowledges support from the Spanish funding grants AYA2016-79006-P (MINECO/FEDER) and PGC2018-094671-B-I00 (MCIU/AEI/FEDER). J.M.D.K., M.C, and J.J.K. gratefully acknowledge funding from the 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 program via the ERC Starting Grant MUSTANG (grant agreement No. 714907). F.B. acknowledges funding from the European Unions Horizon 2020 research and innovation program (grant agreement No. 726384/EMPIRE). R.S.K. and S.C.O.G. acknowledge financial support from the German Research Foundation (DFG) via the collaborative research center (SFB 881, Project-ID 138713538) "The Milky Way System" (subprojects A1, B1, B2, and B8). They also acknowledge funding from the Heidelberg Cluster of Excellence STRUCTURES in the framework of Germany's Excellence Strategy (grant EXC-2181/1 - 390900948) and from the European Research Council via the ERC Synergy Grant ECOGAL (grant 855130) and the ERC Advanced Grant STARLIGHT (grant 339177). K.K. gratefully acknowledges funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) in the form of an Emmy Noether Research Group (grant No. KR4598/2-1, PI: Kreckel). A.E.S. is supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1903834. This Letter makes use of the following ALMA data: ADS/JAO.ALMA#2012.1.00650.S, ADS/JAO.ALMA#2013.1.01161.S, ADS/JAO.ALMA#2015.1.00925.S, ADS/JAO.ALMA#2015.1.00956.S, ADS/JAO.ALMA#2017.1.00392.S, ADS/JAO.ALMA#2017.1.00886.L, ADS/JAO.ALMA#2018.1.01321.S, ADS/JAO.ALMA#2018.1.01651.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. We acknowledge the usage of the Extragalactic Distance Database (; Tully et al. 2009) and the SAO/NASA Astrophysics Data System ( Facility: ALMA. - Software: CASA (McMullin et al. 2007), Astropy (Astropy Collaboration et al. 2018), spectral-cube (Ginsburg et al. 2019), SpectralCubeTools (
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
European Research Council (ERC)694343
Natural Sciences and Engineering Research Council of Canada (NSERC)RGPIN-2017-03987
Fondo Europeo de Desarrollo Regional (FEDER)UNSPECIFIED
Ministerio de Economía, Industria y Competitividad (MINECO)AYA2016-79006-P
Ministerio de Ciencia, Innovación y Universidades (MCIU)PGC2018-094671-B-I00
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)SFB 881
Bundesministerium für Bildung und Forschung (BMBF)EXC-2181/1 - 390900948
European Research Council (ERC)855130
European Research Council (ERC)339177
Deutsche Forschungsgemeinschaft (DFG)KR4598/2-1
NSF Astronomy and Astrophysics FellowshipAST-1903834
Subject Keywords:Millimeter astronomy ; Molecular gas ; Late-type galaxies
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Millimeter astronomy (1061); Molecular gas (1073); Late-type galaxies (907)
Record Number:CaltechAUTHORS:20200925-135425607
Persistent URL:
Official Citation:Jiayi Sun et al 2020 ApJL 901 L8
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105567
Deposited By: George Porter
Deposited On:25 Sep 2020 22:13
Last Modified:25 Sep 2020 22:13

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