J/ApJ/901/L8 Molecular gas properties of 70 PHANGS-ALMA galaxies (Sun+, 2020)
Molecular gas properties on cloud scales across the local star-forming galaxy
population.
Sun J., Leroy A.K., Schinnerer E., Hughes A., Rosolowsky E., Querejeta M.,
Schruba A., Liu D., Saito T., Herrera C.N., Faesi C., Usero A., Pety J.,
Kruijssen J.M.D., Ostriker E.C., Bigiel F., Blanc G.A., Bolatto A.D.,
Boquien M., Chevance M., Dale D.A., Deger S., Emsellem E., Glover S.C.O.,
Grasha K., Groves B., Henshaw J., Jimenez-Donaire M.J., Kim J.J.,
Klessen R.S., Kreckel K., Lee J.C., Meidt S., Sandstrom K., Sardone A.E.,
Utomo D., Williams T.G.
<Astrophys. J., 901, L8 (2020)>
=2020ApJ...901L...8S 2020ApJ...901L...8S
ADC_Keywords: Millimetric/submm sources; Carbon monoxide; Galaxies, nearby;
Molecular data; Velocity dispersion
Keywords: Millimeter astronomy ; Molecular gas ; Late-type galaxies
Abstract:
Using the PHANGS-ALMA CO(2-1) survey, we characterize molecular gas
properties on ∼100pc 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 (3.4dex),
velocity dispersions (1.7dex), and turbulent pressures (6.5dex) 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 ∼100pc 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.
Description:
We include the 70 "Physics at High Angular resolution in Nearby
GalaxieS with the Atacama Large Millimeter/submillimeter Array"
(PHANGS-ALMA) galaxies that had fully processed ALMA data by 2019
December.
The PHANGS-ALMA CO (2-1) data have native spatial resolutions of
50-150pc at the distances of the target galaxies, and 1σ noise
levels of 0.2-0.3K per 2.5km/s channel. They combine ALMA
interferometric array and single-dish observations to recover emission
across the full range of spatial scales
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 71 70 Galaxy sample
tableb1.dat 79 182628 Table of key measurements
--------------------------------------------------------------------------------
See also:
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/ApJ/772/107 : Giant molecular clouds in nearby gal. (Donovan Meyer+, 2013)
J/ApJ/784/3 : The PAWS catalogs of GMCs and islands in M51 (Colombo+, 2014)
J/A+A/582/A86 : Catalogue of features in the S4G (Herrera-Endoqui+, 2015)
J/ApJS/219/4 : S4G pipeline 4: multi-component decompositions (Salo+, 2015)
J/ApJ/834/57 : MW molecular clouds from 12CO (Miville-Deschenes+, 2017)
J/AJ/156/18 : APOGEE:Binary companions of evolved stars (Price-Whelan+, 2018)
J/ApJ/860/172 : Cloud-scale molecular gas properties in 15 gal. (Sun+, 2018)
J/ApJ/897/122 : Rotational velocities for PHANGS sample of gal. (Lang+, 2020)
J/ApJ/892/148 : Molecular ISM in nearby star-forming galaxies (Sun+, 2020)
http://www.phangs.org/ : PHANGS survey home page
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Name Galaxy name
11- 11 A1 --- f_Name Flag on individual galaxy (1)
13- 13 A1 --- Bar [YN?] Presence of identifiable stellar bar(s)
15- 15 A1 --- Arm [YN] Presence of identifiable spiral arm(s)
17- 21 F5.2 Mpc Dist [2/26.1] Distance,
Tully+ (2009AJ....138..323T 2009AJ....138..323T)
23- 26 F4.1 deg i [8.7/75] Galaxy inclination,
Lang+ (2020, J/ApJ/897/122)
28- 32 F5.1 deg PA Galaxy position angle,
Lang+ (2020, J/ApJ/897/122)
34- 37 F4.1 10+9Msun Mstar [1.2/83.1] Galaxy global stellar mass
39- 43 F5.2 Msun/yr SFR [0.06/14.4] Galaxy global star formation rate
45- 48 F4.1 kpc Reff [1/12] Galaxy effective (half-mass) radius (2)
50- 54 F5.3 K Tnoise [0.01/0.1] CO data rms noise
at 150pc resolution
56- 60 F5.3 --- rch [0.05/0.2] CO data channel-to-channel
correlation at 150pc resolution
62- 64 I3 % fCO [28/105] CO flux completeness
at 150pc resolution
66- 66 A1 --- f_fCO Flag on fCO (3)
68- 71 I4 --- Nlos [76/6438] Number of independent sightlines
at 150pc resolution
--------------------------------------------------------------------------------
Note (1): Flag on individual galaxy as follows:
a = These three very nearby galaxies are only observed by the ACA 7-m
and total power telescopes. Because of their proximity, the data
still have linear resolutions matched to the other galaxies in the
sample;
b = Measurements in these four galaxies are not presented in Section 3
in the paper.
Note (2): Effective (half-mass) radius estimated from the measured stellar
scale length, Leroy et al. (2019ApJS..244...24L 2019ApJS..244...24L), A. K. Leroy et al.
(2020a, in preparation);
Note (3): Flag on fCO as follows:
* = The estimated CO flux completeness exceeds 100% for these
two targets. This is due to either low S/N data (NGC 4424) or
calibration mismatch between the interferometric and single dish data
(NGC 1317).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Name Galaxy name
10- 12 I3 pc scale [90/150] CO data resolution
14- 19 F6.3 kpc rgal [0/15.16] Galactocentric radius
21- 21 I1 --- Cent [0/1] Measurement in galaxy center
23- 23 I1 --- Arm [0/1] Measurement in spiral arm region
25- 25 I1 --- iArm [0/1] Measurement in inter-arm region
27- 36 E10.3 K.km/s ICO21 [-0.45/2302] CO(2-1) line integrated intensity
38- 47 E10.3 Msun/pc2 Sigma [-2.5/9733] Molecular gas surface density
49- 57 E9.3 km/s Vdisp [0.058/177.7] Velocity dispersion
59- 68 E10.3 K/cm3 Pturb [-54.4/1780000000] Turbulent pressure
70- 79 E10.3 --- aVir [-0.83/137] Virial parameter
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 17-Jan-2022