J/ApJ/859/11 The GALEX-SDSS-WISE Legacy Catalog 2 (GSWLC-2) (Salim+, 2018)
Dust attenuation curves in the local universe: demographics and new laws for
star-forming galaxies and high-redshift analogs.
Salim S., Boquien M., Lee J.C.
<Astrophys. J. 859, 11 (2018)>
=2018ApJ...859...11S 2018ApJ...859...11S (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs; Extinction; Ultraviolet; Spectra, optical;
Infrared sources; Surveys; Energy distributions; Redshifts
Keywords: dust; extinction; galaxies: fundamental parameters
Abstract:
We study the dust attenuation curves of 230,000 individual galaxies in
the local universe, ranging from quiescent to intensely star-forming
systems, using GALEX, SDSS, and WISE photometry calibrated on the
Herschel ATLAS. We use a new method of constraining SED fits with
infrared luminosity (SED+LIR fitting), and parameterized attenuation
curves determined with the CIGALE SED-fitting code. Attenuation curve
slopes and UV bump strengths are reasonably well constrained
independently from one another. We find that Aλ/AV
attenuation curves exhibit a very wide range of slopes that are on
average as steep as the curve slope of the Small Magellanic Cloud
(SMC). The slope is a strong function of optical opacity. Opaque
galaxies have shallower curves --in agreement with recent radiative
transfer models. The dependence of slopes on the opacity produces an
apparent dependence on stellar mass: more massive galaxies have
shallower slopes. Attenuation curves exhibit a wide range of UV bump
amplitudes, from none to Milky Way (MW)-like, with an average strength
one-third that of the MW bump. Notably, local analogs of high-redshift
galaxies have an average curve that is somewhat steeper than the SMC
curve, with a modest UV bump that can be, to first order, ignored, as
its effect on the near-UV magnitude is 0.1 mag. Neither the slopes nor
the strengths of the UV bump depend on gas-phase metallicity.
Functional forms for attenuation laws are presented for normal
star-forming galaxies, high-z analogs, and quiescent galaxies. We
release the catalog of associated star formation rates and stellar
masses (GSWLC-2; GALEX-SDSS-WISE Legacy Catalog 2).
Description:
The current study updates the GALEX-SDSS-WISE Legacy Catalog (GSWLC),
a catalog of physical parameters of 700,000 galaxies in the local
universe from the Bayesian SED fitting (see GSWLC-1;
Salim+ 2016ApJS..227....2S 2016ApJS..227....2S).
There are three versions of the catalog (GSWLC-A, M, D), depending on
the depth of the UV photometry. Same galaxy may appear in different
catalogs if it was observed with UV observations of different depth.
The number after A, M, D (e.g., GSWLC-M2) indicates the version of the
catalog. Please cite the version in your publication.
In GSWLC-2 the mid-IR flux from 22 micron WISE (or 12 micron, if 22um
is not detected) is used in the SED fitting jointly with UV/optical
photometry to derive more accurate SFRs. Furthermore, the slope of the
attenuation curve and the strength of the 2200 Angstrom feature are
free parameters. Other modeling assumptions are the same as in GSWLC-1.
GSWLC-2 uses a new variant of energy-balance SED fitting that does not
require the modeling of the IR SED (which, without the far-IR is not
well constrained with general IR models), allowing the same high
sampling of models as just the UV/optical SED fitting. Instead, we use
luminosity-dependent IR templates to derive the total IR luminosity,
which we further correct to agree with Herschel PACS+SPIRE IR
luminosities (see version 1.2 of Valiante+ 2016, J/MNRAS/462/3146),
and use it as a direct constraint in the SED fitting. We call this
method the SED+LIR fitting. We use only photometry from unWISE (see
II/363). If galaxy is classified as having a narrow-line (Type 2) AGN,
its IR luminosity is corrected before it is used in the SED fitting.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
gswlc-a2.dat 181 640659 *Shallow, "All-sky" catalog (GSWLC-A2;
Covers 88% of SDSS)
gswlc-m2.dat 181 361328 *Medium-deep catalog (GSWLC-M2;
Covers 49% of SDSS)
gswlc-d2.dat 181 48401 *Deep catalog (GSWLC-D2;
Covers 7% of SDSS)
gswlc-x2.dat 181 659229 *Master catalog taking the deepest of
GSWLC-A, M and D (GSWLC-X2; Covers 90% of SDSS)
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Note on gswlc-a2.dat, gswlc-m2.dat and gswlc-d2.dat: All three catalogs
yield good SFRs for main-sequence galaxies. GSWLC-M and D are
recommended for galaxies off the main sequence (passive or nearly
passive galaxies).
Note on gswlc-x2.dat: GSWLC-X is recommended only for main-sequence galaxies,
for which the accuracy of SFRs is similar in all three catalogs.
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See also:
III/167 : Atlas of UV spectra of star-forming galaxies (Kinney+ 1993)
VI/139 : Herschel Observation Log (Herschel Science Centre, 2013)
II/335 : Revised cat. of GALEX UV sources (GUVcat_AIS GR6+7) (Bianchi+ 2017)
II/363 : The band-merged unWISE Catalog (Schlafly+, 2019)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
J/MNRAS/338/525 : Recent star formation in UCM gal. (Perez-Gonzalez+, 2003)
J/ApJ/706/553 : Fluxes in nearby star-forming galaxies (Boquien+, 2009)
J/A+A/545/A141 : UV selected sources in the GOODS-S field (Buat+, 2012)
J/ApJ/793/115 : UV-continuum slopes beta for z∼4-8 galaxies (Bouwens+, 2014)
J/ApJ/810/71 : UV mag of cand. galaxies at 3~<z~<8.5 (Finkelstein+, 2015)
J/MNRAS/462/3146 : Herschel-ATLAS DR1 (HATLAS) (Valiante+, 2016)
J/MNRAS/466/4540 : SUMaC I (Hagen+, 2017)
http://salims.pages.iu.edu/gswlc/ : GALEX-SDSS-WISE LEGACY CATALOG (GSWLC) home
http://unwise.me/ : unWISE homepage
Byte-by-byte Description of file: gswlc-*2.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- ObjID SDSS DR10 photometric identification number
21- 39 I19 --- GLXID ?=-99 GALEX GR6/7 photometric identification
number
41- 44 I4 --- Plate [266/6064] SDSS spectroscopic plate number
46- 50 I5 d MJD [51578/56107] SDSS spectroscopic plate
Modified Julian Date
52- 55 I4 --- Fiber [1/1000] SDSS spectroscopic fiber
identification number
57- 66 F10.6 deg RAdeg Right ascension from SDSS (J2000)
68- 77 F10.6 deg DEdeg [-11.3/78.2] Declination from SDSS (J2000)
79- 84 F6.4 --- z [0.01/0.3] Redshift from SDSS
86- 91 F6.2 --- Chi2r [0/30]?=-99 Reduced goodness-of-fit value
for the SED fitting
93- 99 F7.3 --- logMs [7.2/12.5]?=-99 Stellar mass
101- 107 F7.3 --- e_logMs [0/0.9]?=-99 logMs uncertainty
109- 115 F7.3 [Msun/yr] logSFR [-4.5/2.9]?=-99 Log of UV/optical (SED)
stellar formation rate
117- 123 F7.3 [Msun/yr] e_logSFR [0/1.6]?=-99 logSFR uncertainty
125- 131 F7.3 --- Afuv [0/6.2]?=-99 Dust attenuation in
rest-frame FUV
133- 139 F7.3 --- e_Afuv [0/2.9]?=-99 Afuv uncertainty
141- 147 F7.3 --- Ab [0/2.6]?=-99 Dust attenuation in rest-frame B
149- 155 F7.3 --- e_Ab [0/0.8]?=-99 Ab uncertainty
157- 163 F7.3 mag Av [0/2.2]?=-99 Dust attenuation in rest-frame V
165- 171 F7.3 mag e_Av [0/0.7]?=-99 Av uncertainty
173 I1 --- SED [0/6] SED fitting flag (1)
175 I1 --- Survey [1/3] UV (GSWLC) survey (2)
177 I1 --- UV [0/3] UV (GALEX) flag (1=FUV only,
2=NUV only, 3=both, 0=no UV)
179 I1 --- MIR [0/7]? Mid-IR (unWISE) flag (3)
181 I1 --- MGS [0/1] Main Galaxy Sample (MGS) flag
(1 = in MGS) (4)
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Note (1): SED fitting flag as follows:
0 = OK
1 = broad-line spectrum
2 = Χ2r>30.5
5 = missing SDSS photometry
If there are multiple reasons for setting the flag, the flag value
will be the sum of individual flag values.
When the SED flag is set, the SED fitting parameters are not given.
Note (2): UV survey as follows:
1 = GSWLC-A (Shallow, "All-sky" catalog)
2 = GSWLC-M (Medium-deep catalog)
3 = GSWLC-D (Deep catalog)
Note (3): Mid-IR (unWISE) flag as follows:
0 = no mid-IR
1 = LIR based on 12um
2 = LIR based on 22um
5 = LIR corrected for mid-IR AGN emission
If there are multiple reasons for setting the flag, the flag value
will be the sum of individual flag values.
When mid-IR measurements are not present, SED fitting parameters
default to GSWLC-1 values.
Note (4): Regardless of the catalog version or depth, for statistical studies
we recommend using galaxies from the SDSS Main Galaxy Survey (MGS=1).
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History:
Downloaded at: https://salims.pages.iu.edu/gswlc/#catalog-download
(End) Emmanuelle Perret [CDS] 18-Mar-2026