J/A+A/704/A232 Photometric stellar masses for S4G galaxies (Ebrova+, 2025)
Photometric stellar masses for galaxies in DESI Legacy Imaging Surveys.
Ebrova I., Bilek M., Eliasek J.
<Astron. Astrophys. 704, A232 (2025)>
=2025A&A...704A.232E 2025A&A...704A.232E (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, photometry ; Optical ; Morphology ; Extinction ;
Stars, masses
Keywords: techniques: photometric - galaxies: general - galaxies: photometry -
galaxies: stellar content
Abstract:
In many areas of extragalactic astrophysics, we need to convert the
luminosity of a galaxy into its stellar mass. In this work, we aim to
find a simple and effective formula to estimate the stellar mass from
the images of galaxies delivered by the currently popular DESI Legacy
Imaging Surveys. This survey provides an unsurpassed combination of a
deep imaging with an extensive sky coverage in up to four photometric
bands. We calibrated the sought formula against a sample of local
galaxies observed by the Spitzer Survey of Stellar Structure in
Galaxies (S4 G) that was directly dedicated to measure the stellar
masses. For the absolute magnitudes Mg and Mr of a galaxy in the
Legacy Surveys g and r bands, we find that the stellar masses can be
estimated as 0.673Mg-1.108Mr+0.996 with the scatter of 25%. Employing
more complex functions does not improve the estimate appreciably, even
after including the galaxy ellipticity, Sersic index, or the
magnitudes in different Legacy Surveys bands. Generally, measurements
in r band were the most helpful ones, while adding z-band measurements
did not improve the mass estimate much. We provide a Python-based
script photomass_ls.py to automatically download images of any galaxy
from the Legacy Surveys database, create image masks, generate GALFIT
input files with well-assessed initial values, perform the GALFIT
photometry, and calculate the stellar mass estimate. Additionally, we
tuned another version of the formula to the magnitudes provided by the
Siena Galaxy Atlas 2020 (SGA-2020) with a scatter of 29%. For both -
our default and SGA-2020 formula, we offer two alternatives derived
from different calibrations of S4G masses that were based on
different methods and assumptions.
Description:
Sample of 1732 galaxies that were used in the paper to derive formulae
for computing stellar masses from Legacy Surveys data.
The sample was processed by photomass_ls.py.
Contains:
* stellar mass and basic galaxy parameters from the Spitzer Survey of
Stellar Structure in Galaxies (S4G)
* Galactic extinction
* parameters of the GALFIT fit by a 2-D single-component Sersic profile
* stellar mass computed by Eq.(1) of the paper:
logM*(Eq1)=0.673*Mg-1.108*Mr+0.996
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb.dat 254 1732 Galaxy parameters and stellar masses from LS data
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See also:
J/PASP/122/1397 : Spitzer Survey of Stellar Structure in Galaxies (Sheth+ 2010)
Byte-by-byte Description of file: tableb.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Galaxy name (1)
12- 20 F9.5 deg RAdeg Right ascension (J2000) (1)
22- 30 F9.5 deg DEdeg Declination (J2000) (1)
32- 36 F5.1 arcsec radius Semi-major axis (mu(3.6um)=25.5mag/arcsec2) (1)
38- 43 F6.3 Mpc Dmean Mean distance (redshift-independent) (1)
45- 50 F6.3 [Msun] logMS4G Stellar mass from S4G catalog (1)
52- 56 F5.3 mag AgDES Galactic extinction in g-band
58- 62 F5.3 mag ArDES Galactic extinction in r-band
64- 68 F5.3 mag AzDES Galactic extinction in z-band
70- 75 F6.3 mag gmagInt Integrated magnitude in g-band (3)
77- 82 F6.3 mag rmagInt Integrated magnitude in r-band (3)
84- 89 F6.3 mag zmagInt Integrated magnitude in z-band (3)
91- 95 F5.3 --- b/a-g Axis ratio (b/a) in g-band (3)
97-101 F5.3 --- b/a-r Axis ratio (b/a) in r-band (3)
103-107 F5.3 --- b/a-z Axis ratio (b/a) in z-band (3)
109-113 F5.3 --- n-g Sersic index in g-band (3)
115-119 F5.3 --- n-r Sersic index in r-band (3)
121-126 F6.3 --- n-z Sersic index in z-band (3)
128-134 F7.3 arcsec Re-g Effective radius in g-band (3)
136-142 F7.3 arcsec Re-r Effective radius in r-band (3)
144-150 F7.3 arcsec Re-z Effective radius in z-band (3)
152-158 F7.3 deg PA-g [] Position angle (North=0, East=90)
in g-band (3)
160-166 F7.3 deg PA-r [] Position angle (North=0, East=90)
in r-band (3)
168-174 F7.3 deg PA-z [] Position angle (North=0, East=90)
in z-band (3)
176-182 F7.3 mag gMAG Absolute magnitude (corrected, g-band)
184-190 F7.3 mag rMAG Absolute magnitude (corrected, r-band)
192-198 F7.3 mag zMAG Absolute magnitude (corrected, z-band)
200-205 F6.3 [Msun] logMEq1 Stellar mass from Eq.1
(Eskew et al., 2012AJ....143..139E 2012AJ....143..139E) (4)
207-212 F6.3 [Msun] logMEq2 Stellar mass from Eq.2
(Meidt et al., 2014ApJ...788..144M 2014ApJ...788..144M) (5)
214-219 F6.3 [Msun] logMEq3 Stellar mass from Eq.3
(Querejeta et al. 2015ApJS..219....5Q 2015ApJS..219....5Q) (6)
221-228 F8.5 --- z Redshift (heliocentric)
230-236 F7.4 mag Kcorrg K-correction in g-band (2)
238-244 F7.4 mag Kcorrr K-correction in r-band (2)
247-250 F4.1 --- TT ? Morphological type (RC3) (1)
252-254 F3.1 --- e_TT ? Uncertainty of morphological type (1)
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Note (1): Name, RA, DE, radius, Dmean, logM_S4G, TT, e_TT adapted from the
S4G catalog (Sheth et al., 2010PASP..122.1397S 2010PASP..122.1397S, Cat. J/PASP/122/1397).
Note (2): K corrections (Kcorr) to rest-frame colors calculated using
K-correction calculator http://kcor.sai.msu.ru
Note (3): parameters of the GALFIT fit by a 2-D single-component Sersic profile.
Note (4): logMEq1 stellar mass computed by Equation (1) of the paper based on
the Eskew et al. (2012AJ....143..139E 2012AJ....143..139E) calibration: 0.673Mg-1.108Mr+0.996
Note (5): logM_Eq2 stellar mass computed by Equation (2) of the paper based on
the Meidt et al. (2014ApJ...788..144M 2014ApJ...788..144M) calibration: 0.582Mg-1.023Mr+0.992
Note (6): logM_Eq3 stellar mass computed by Equation (3) of the paper based on
the Querejeta et al. (2015ApJS..219....5Q 2015ApJS..219....5Q) calibration: 0.627Mg-1.065Mr+1.062
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Acknowledgements:
From Ivana Ebrova, ebrova.ivana(at)gmail.com
Funded by the European Union under the Marie Sklodowska-Curie grant
agreement No. 101067618 (GalaxyMergers).
Disclaimer:
Funded by the European Union. Views and opinions expressed are however
those of the author(s) only and do not necessarily reflect those of the
European Union or European Research Executive Agency (REA).
Neither the European Union nor REA can be held responsible for them.
(End) Patricia Vannier [CDS] 21-Oct-2025