J/ApJ/892/148 Molecular ISM in nearby star-forming galaxies (Sun+, 2020)
Dynamical equilibrium in the molecular ISM in 28 nearby star-forming galaxies.
Sun J., Leroy A.K., Ostriker E.C., Hughes A., Rosolowsky E., Schruba A.,
Schinnerer E., Blanc G.A., Faesi C., Kruijssen J.M.D., Meidt S., Utomo D.,
Bigiel F., Bolatto A.D., Chevance M., Chiang I.-D., Dale D., Emsellem E.,
Glover S.C.O., Grasha K., Henshaw J., Herrera C.N., Jimenez-Donaire M.J.,
Lee J.C., Pety J., Querejeta M., Saito T., Sandstrom K., Usero A.
<Astrophys. J., 892, 148-148 (2020)>
=2020ApJ...892..148S 2020ApJ...892..148S (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby; Interstellar medium; Molecular data;
Carbon monoxide
Keywords: Interstellar molecules; Star formation; Interstellar dynamics
Abstract:
We compare the observed turbulent pressure in molecular gas, Pturb,
to the required pressure for the interstellar gas to stay in
equilibrium in the gravitational potential of a galaxy, PDE. 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 Pturb correlates with--but almost always exceeds--the estimated
PDE 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 PDE on cloud scales, which
accounts for molecular gas self-gravity, external gravity, and ambient
pressure, agrees well with the observed Pturb in galaxy disks. We
also find that molecular gas with cloud-scale
Pturb∼PDE≳105kBKcm-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 Pturb and the observed SFR surface
density, ΣSFR, 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 ΣSFR and kpc-scale PDE 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 PDE reported in previous
works.
Description:
We use PHANGS-ALMA CO (2-1) data to trace molecular gas distribution
and kinematics across the star-forming disks in all our sample
galaxies (A. K. Leroy et al. 2020, in preparation; also see
Sun+ 2018, J/ApJ/860/172). These CO observations include data from
both the 12m array and the Morita Atacama Compact Array (ACA;
consisting of the 7m array and four 12m total power antennas). The
angular resolution (i.e., beam FWHM) ranges between 1.0"-1.8",
corresponding to 25-120pc linear resolution at the targets' distances.
To homogenize the CO data, we convolve all the data cubes to two
different linear resolutions, 60 and 120pc, whenever possible.
The 28 galaxies selected from the PHANGS-ALMA parent sample also have
a complete set of multiwavelength supporting data, including HI 21cm
line data from the Karl G. Jansky Very Large Array (VLA) and the
Australia Telescope Compact Array (ATCA), 3.6um imaging data from
the Spitzer Space Telescope, near-UV data from the Galaxy Evolution
Explorer (GALEX), and mid-IR data from the Wide-field Infrared Survey
Explorer (WISE). See Section 2.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 35 28 Galaxy sample
tablec1.dat 103 1762 Table of key measurements
--------------------------------------------------------------------------------
See also:
J/ApJ/428/693 : Rosette Nebula & Maddalena Cloud structures (Williams+ 1994)
J/ApJ/551/852 : FCRAO CO survey of the outer Galaxy (Heyer+, 2001)
J/ApJ/686/948 : CO in extragalactic giant molecular clouds (Bolatto+, 2008)
J/AJ/136/2563 : HI Nearby Galaxy Survey, THINGS (Walter+, 2008)
J/AJ/136/2782 : Star formation efficiency in nearby galaxies (Leroy+, 2008)
J/ApJ/699/1092 : Giant molecular clouds (SRBY) (Heyer+, 2009)
J/PASP/122/1397 : Spitzer Survey of Stellar Structure in Gal. (Sheth+, 2010)
J/ApJ/772/107 : Giant molecular clouds in nearby gal. (Donovan Meyer+, 2013)
J/AJ/146/150 : Velocity dispersions of nearby galaxies (Caldu-Primo+, 2013)
J/ApJ/784/3 : The PAWS catalogs of GMCs and islands in M51 (Colombo+, 2014)
J/ApJ/803/16 : Giant MoCs in NGC4526 based on 12CO (Utomo+, 2015)
J/ApJS/219/4 : S4G pipeline 4: multi-component decompositions (Salo+, 2015)
J/A+A/582/A86 : Catalogue of features in the S4G (Herrera-Endoqui+, 2015)
J/ApJ/834/57 : MW molecular clouds from 12CO (Miville-Deschenes+, 2017)
J/ApJS/233/22 : xCOLD GASS catalog (Saintonge+, 2017)
J/ApJ/858/90 : Radial profiles of 5 nearby galaxies (Gallagher+, 2018)
J/ApJ/860/172 : Cloud-scale molecular gas properties in galaxies (Sun+, 2018)
J/AJ/156/18 : APOGEE:Bin. companions of evolved stars (Price-Whelan+, 2018)
http://www.phangs.org/ : PHANGS survey home page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Galaxy Galaxy name
10- 14 F5.2 Mpc Dist [4.3/26.1] Distance (1)
16- 19 F4.1 deg Inc [8.7/75] Inclination angle (2)
21- 25 F5.2 [Msun] logMstar [9.3/10.9] Global stellar mass (3)
27- 30 F4.1 arcsec Reff [14.9/89.1] Effective radius (4)
32- 35 F4.1 arcsec Rstar [15.3/73.5] Stellar disk scale length (5)
--------------------------------------------------------------------------------
Note (1): Distance from the Extragalactic Distance Database
(Tully+ 2009AJ....138..323T 2009AJ....138..323T).
Note (2): Inclination angle from "Physics at High Angular resolution in
Nearby GalaxieS" (PHANGS), Lang et al. (2020ApJ...897..122L 2020ApJ...897..122L);
see www.phangs.org
Note (3): logarithmic global stellar mass from the z=0 Multiwavelength
Galaxy Synthesis (z0MGS; Leroy+ 2019ApJS..244...24L 2019ApJS..244...24L).
Note (4): Effective radius from "Low-J CO Line Ratios From Single DISH
CO Mapping Surveys and PHANGS-ALMA". Leroy et al. 2021, ApJ, subm.
see www.phangs.org
Note (5): Stellar disk scale length from the Spitzer Survey of Stellar
Structure in Galaxies (S4G; Salo+ (2015, J/ApJS/219/4).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablec1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Galaxy Host galaxy name
10 I1 --- inDisk [0/1] Row corresponds to a "disk"
aperture (1) or not (0)
12- 16 F5.3 --- fCO120pc [0.001/3.8] CO flux recovery
fraction, 120pc scale
18- 26 E9.3 K/cm3 Pturb120pc [536.7/3.7e+08] Mass-weighted mean
turbulent pressure, 120pc scale
28- 36 E9.3 K/cm3 PDE120pc [2325/1.7e+08] Dynamical
equilibrium pressure, 120pc scale
38- 43 F6.3 --- fCO60pc [-3.4/1]? CO flux recovery
fraction, 60pc scale
45- 53 E9.3 K/cm3 Pturb60pc [3700/1.3e+08]? Mass-weighted mean
turbulent pressure, 60pc scale
55- 63 E9.3 K/cm3 PDE60pc [9251/9.3e+07]? Dynamical
equilibrium pressure, 60pc scale
65- 73 E9.3 K/cm3 PDEkpc [1334/6e+06] Dynamical equilibrium
pressure, kpc scale
75- 83 E9.3 K/cm3 PDEkpc11 [1453/4e+06] Dynamical equilibrium
pressure, kpc scale, assuming a
fixed sigma{gas,z}=11km/s
85- 93 E9.3 Msun/yr/kpc2 SigSFRkpc [0.0005/0.5]? Star formation rate
surface density, kpc scale
95- 103 E9.3 --- Rmolkpc [0/144.7]? Molecular-to-atomic gas
ratio, kpc scale
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 17-Aug-2021