J/ApJ/945/L19 SFR & molecular gas surface densities in nearby gal. (Sun+, 2023)
Star formation laws and efficiencies across 80 nearby galaxies.
Sun J., Leroy A.K., Ostriker E.C., Meidt S., Rosolowsky E., Schinnerer E.,
Wilson C.D., Utomo D., Belfiore F., Blanc G.A., Emsellem E., Faesi C.,
Groves B., Hughes A., Koch E.W., Kreckel K., Liu D., Pan H.-A., Pety J.,
Querejeta M., Razza A., Saito T., Sardone A., Usero A., Williams T.G.,
Bigiel F., Bolatto A.D., Chevance M., Dale D.A., Gensior J.,
Glover S.C.O., Grasha K., Henshaw J.D., Jimenez-Donaire M.J.,
Klessen R.S., Kruijssen J.M.D., Murphy E.J., Neumann L., Teng Y.-H.,
Thilker D.A.
<Astrophys. J., 945, L19 (2023)>
=2023ApJ...945L..19S 2023ApJ...945L..19S
ADC_Keywords: Galaxies, nearby; Interstellar medium; Star Forming Region;
Molecular data; Carbon monoxide; Infrared
Keywords: Interstellar medium ; Star formation ; Galaxy evolution ;
Scaling relations
Abstract:
We measure empirical relationships between the local star formation
rate (SFR) and properties of the star-forming molecular gas on 1.5kpc
scales across 80 nearby galaxies. These relationships, commonly
referred to as "star formation laws," aim at predicting the local SFR
surface density from various combinations of molecular gas surface
density, galactic orbital time, molecular cloud free fall time, and
the interstellar medium dynamical equilibrium pressure. Leveraging a
multiwavelength database built for the Physics at High Angular
Resolution in Nearby Galaxies (PHANGS) survey, we measure these
quantities consistently across all galaxies and quantify systematic
uncertainties stemming from choices of SFR calibrations and the
CO-to-H2 conversion factors. The star formation laws we examine show
0.3-0.4dex of intrinsic scatter, among which the molecular
Kennicutt-Schmidt relation shows a ∼10% larger scatter than the other
three. The slope of this relation ranges β∼0.9-1.2, implying that
the molecular gas depletion time remains roughly constant across the
environments probed in our sample. The other relations have shallower
slopes (β∼0.6-1.0), suggesting that the star formation efficiency
per orbital time, the star formation efficiency per free fall time,
and the pressure-to-SFR surface density ratio (i.e., the feedback
yield) vary systematically with local molecular gas and SFR surface
densities. Last but not least, the shapes of the star formation laws
depend sensitively on methodological choices. Different choices of SFR
calibrations can introduce systematic uncertainties of at least
10%-15% in the star formation law slopes and 0.15-0.25dex in their
normalization, while the CO-to-H2 conversion factors can additionally
produce uncertainties of 20%-25% for the slope and 0.10-0.20dex for
the normalization.
Description:
We base our analysis on the PHANGS high-level measurement database
described in Sun+ 2022AJ....164...43S 2022AJ....164...43S (S22). In this paper, we use the
latest version of this database, which sees many improvements over the
version published in S22. We summarize these improvements and announce
the online release of the associated data products in Appendix A.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
galaxies.dat 10 80 List of the 80 nearby galaxies; table added by CDS
tablea1.dat 372 5533 Catalog of all measurements used in this work;
see Appendix A
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See also:
J/AJ/136/2782 : Star formation efficiency in nearby galaxies (Leroy+, 2008)
J/AJ/136/2563 : HI Nearby Galaxy Survey, THINGS (Walter+, 2008)
J/ApJ/846/71 : M51 ISM structures from the CO maps of PAWS (Leroy+, 2017)
J/MNRAS/478/1611 : Local Volume H I Survey (LVHIS) (Koribalski+, 2018)
J/ApJ/860/172 : Cloud-scale molecular gas data in 15 galaxies (Sun+, 2018)
J/ApJ/872/16 : Integrated star formation law revisited (de los Reyes+, 2019)
J/ApJS/244/24 : z=0 Multiwavelength Galaxy Synthesis (z0MGS). I. (Leroy+, 2019)
J/ApJ/882/5 : ALMA data for 5 luminous & ultralum. IR gal. (Wilson+, 2019)
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)
J/ApJ/901/L8 : Molecular gas data of 70 PHANGS-ALMA galaxies (Sun+, 2020)
J/ApJ/908/61 : Integrated Star Formation Law revisited. II. (Kennicutt+, 2021)
J/ApJS/257/43 : PHANGS-ALMA: arcsecond CO(2-1) imaging of gal. (Leroy+, 2021)
J/ApJ/927/149 : Low-J CO line ratios for 152 CO map pairs (Leroy+, 2022)
http://www.canfar.net/storage/vault/list/phangs/RELEASES/Sun_etal_2022 : PHANGS
online database
Byte-by-byte Description of file: galaxies.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Galaxy name
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Galaxy name (gal_name)
12- 20 F9.5 deg RAdeg Aperture center degree of Right
Ascension (J2000)
22- 30 F9.5 deg DEdeg [-74/22] Aperture center degree
of Declination (J2000)
32- 40 E9.3 Msun/yr/kpc2 SigSFRHaW4c [0/0.7]? SFR surface density;
Ha+22um (SigmaSFRHaW4recal)
42- 48 E7.1 Msun/yr/kpc2 e_SigSFRHaW4c [9.7e-06/0.007]? Uncertainty in
SigSFRHaW4c
(eSigmaSFR_HaW4recal)
50- 58 E9.3 Msun/yr/kpc2 SigSFRFUVW4c [0/0.6]? SFR surface density;
FUV+22um (SigmaSFRFUVW4recal)
60- 66 E7.1 Msun/yr/kpc2 e_SigSFRFUVW4c [6e-06/0.0005]? Uncertainty in
SigSFRFUVW4c
(e_Sigma-SFR-FUVW4recal)
68- 76 E9.3 Msun/yr/kpc2 SigSFRHacor [5.8e-05/0.6]? SFR surface
density; AV-corrected Ha
(Sigma-SFR-Hacorr)
78- 84 E7.1 Msun/yr/kpc2 e_SigSFRHacor [4e-07/6e-05]? Uncertainty in
SigSFR-Hac (e_Sigma-SFR-Hacorr)
86- 94 E9.3 Msun/pc2 SigMol-S20 [0/772] Molecular gas surface
density; S20 αCO
(Sigma-mol-S20) (1)
96- 102 E7.1 Msun/pc2 e_SigMol-S20 [0.018/1] Uncertainty in
SigMol-S20 (e_Sigma-mol-S20)
104- 112 E9.3 Msun/pc2 SigMol-MW [0/1263] Molecular gas surface
density; Galactic αCO
(Sigma-mol-MW)
114- 120 E7.1 Msun/pc2 e_SigMol-MW [0.01/1.7] Uncertainty in
SigMol-MW (e_Sigma-mol-MW)
122- 130 E9.3 Msun/pc2 SigMol-B13 [0/166.3]? Molecular gas
surface density; B13
αCO (Sigma-mol-B13) (1)
132- 138 E7.1 Msun/pc2 e_SigMol-B13 [0.009/0.6]? Uncertainty in
SigMol-B13 (e_Sigma-mol-B13)
140- 148 E9.3 Msun/pc2 SigMol-G20 [0/258.1]? Molecular gas
surface density; G20
αCO (Sigma-mol-G20) (1)
150- 156 E7.1 Msun/pc2 e_SigMol-G20 [0.016/0.7]? Uncertainty in
SigMol-G20 (e_Sigma-mol-G20)
158- 166 E9.3 Msun/yr/kpc2 SigMol-torb-S20 [0/6]? Molecular gas surface
density per orbital time; S20
αCO
(Sigmamolpertorb_S20) (1)
168- 174 E7.1 Msun/yr/kpc2 e_SigMol-torb-S20 [9e-05/5.1]? Uncertainty in
SigMol-torb-S20
(eSigmamolpertorbS20)
176- 184 E9.3 Msun/yr/kpc2 SigMol-torb-MW [0/9.5]? Molecular gas surface
density per orbital time;
Galactic αCO
(Sigmamolpertorb_MW)
186- 192 E7.1 Msun/yr/kpc2 e_SigMol-torb-MW [5.8e-05/8.1]? Uncertainty in
SigMol-torb-MW
(eSigmamolpertorbMW)
194- 202 E9.3 Msun/yr/kpc2 SigMol-torb-B13 [0/1.6]? Molecular gas surface
density per orbital time; B13
αCO
(Sigmamolpertorb_B13) (1)
204- 210 E7.1 Msun/yr/kpc2 e_SigMol-torb-B13 [6.6e-05/0.2]? Uncertainty in
SigMol-torb-B13
(eSigmamolpertorbB13)
212- 220 E9.3 Msun/yr/kpc2 SigMol-torb-G20 [0/2.1]? Molecular gas surface
density per orbital time; G20
αCO
(Sigmamolpertorb_G20) (1)
222- 228 E7.1 Msun/yr/kpc2 e_SigMol-torb-G20 [0.0001/1.8]? Uncertainty in
SigMol-torb-G20
(eSigmamolpertorbG20)
230- 238 E9.3 Msun/yr/kpc2 SigMol-tff-S20 [0/544.1]? Molecular gas
surface density per free-fall
time; S20 αCO
(Sigmamolpertff_S20) (1)
240- 246 E7.1 Msun/yr/kpc2 e_SigMol-tff-S20 [0.0004/0.8]? Uncertainty in
SigMol-tff-S20
(eSigmamolpertffS20)
248- 256 E9.3 Msun/yr/kpc2 SigMol-tff-MW [0/891]? Molecular gas surface
density per free-fall time;
Galactic αCO
(Sigmamolpertff_MW)
258- 264 E7.1 Msun/yr/kpc2 e_SigMol-tff-MW [0.0003/1.2]? Uncertainty in
SigMol-tff-MW
(eSigmamolpertffMW)
266- 274 E9.3 Msun/yr/kpc2 SigMol-tff-B13 [0/106]? Molecular gas surface
density per free-fall time; B13
αCO
(Sigmamolpertff_B13) (1)
276- 282 E7.1 Msun/yr/kpc2 e_SigMol-tff-B13 [0.00039/0.22]? Uncertainty in
SigMoltff-B13
(eSigmamolpertffB13)
284- 292 E9.3 Msun/yr/kpc2 SigMol-tff-G20 [0/182]? Molecular gas surface
density per free-fall time; G20
αCO
(Sigmamolpertff_G20) (1)
294- 300 E7.1 Msun/yr/kpc2 e_SigMol-tff-G20 [0.00047/0.3]? Uncertainty in
SigMol-tff-G20
(eSigmamolpertffG20)
302- 310 E9.3 --- P-DE-S20 [0/10080000]? ISM dynamical
equilibrium pressure; S20
αCO (1)
312- 318 E7.1 --- e_P-DE-S20 [20/18000]? Uncertainty in
P-DE-S20
320- 328 E9.3 --- P-DE-MW [0/23760000]? ISM dynamical
equilibrium pressure; Galactic
αCO
330- 336 E7.1 --- e_P-DE-MW [12/40000]? Uncertainty in
P-DE-MW
338- 346 E9.3 --- P-DE-B13 [0/1552000]? ISM dynamical
equilibrium pressure; B13
αCO (1)
348- 354 E7.1 --- e_P-DE-B13 [18/6900]? Uncertainty in
P-DE-B13
356- 364 E9.3 --- P-DE-G20 [0/1556000]? ISM dynamical
equilibrium pressure; G20
αCO (1)
366- 372 E7.1 --- e_P-DE-G20 [23/8500]? Uncertainty in
P-DE-G20
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Note (1): References are:
S20 = Sun+ 2020ApJ...892..148S 2020ApJ...892..148S
B13 = Bolatto+ 2013ARA&A..51..207B 2013ARA&A..51..207B
G20 = Gong+ 2020ApJ...903..142G 2020ApJ...903..142G
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 10-Feb-2025