GALEX–SDSS–WISE LEGACY CATALOG

11Table 1Contents of GALEX–SDSS–WISE Legacy Catalog (GSWLC).
Column number1234567891011121314151617181920212223242526

Column name
ObjID
GLXID
plate
MJD
fiber ID
RADecl.
z2r

log M⇤(log M⇤ )log SFRSED(log SFRSED )AFUV(AFUV )AB(AB )
AV(AV )
flag_sed
UV survey
log SFRmid-IR,AW
flag_wiselog SFRmid-IR,uW
flag_unwise
flag_mgs

Unitsdegdeg
MM
M yr-1
M yr-1
magmagmagmagmagmag
M yr-1
M yr-1

Description
SDSS photometric identification number
GALEX photometric identification number
SDSS spectroscopic plate number
SDSS spectroscopic plate date
SDSS spectroscopic fiber identification number
Right Ascension from SDSS
Declination from SDSS
Redshift from SDSS
Reduced goodnes-of-fit value for the SED fitting
Stellar mass
Error of the stellar mass
UV/optical (SED) star formation rate
Error of the SFR
Dust attenuation in rest-frame FUV
Error of dust attenuation in FUVDust attenuation in rest-frame B
Error of dust attenuation in B
Dust attenuation in rest-frame V
Error of dust attenuation in V
SED fitting flag (0 = OK, 1 = broad-line spectrum, 2 = 2r > 30, 5 = missing SDSS photometry)
1 = GSWLC-A, 2 = GSWLC-M, 3 = GSWLC-D
Mid-IR star formation rate from WISE (AllWISE catalog)
Mid-IR SFR (AllWISE) flag (0 = OK, 1 = no mid-IR SFR (low SSFR), 5 = no 22 µm detection)
Mid-IR star formation rate from WISE (unWISE catalog)
Mid-IR SFR (unWISE) flag (0 = OK, 1 = no mid-IR SFR (low SSFR), 5 = no 22 µm detection)
0 = not in SDSS Main Galaxy Sample (MGS), 1 = in MGS

Columns 10-19 originate from the SED fitting. If there are multiple reasons for setting the flag, the flag value wil be the sum of individual flag values. Whenthe SED (or un/wise) flag is set, the SED fitting parameters (or mid-IR SFR) are not given. Mid-SFRs based on unWISE are recommended over the AllWISE
ones for z < 0.06 samples, large (r > 1000 ) galaxies, or studies that explore dependence of SFR on galaxy size or shape. SFRs and stellar masses are based onChabrier IMF. Missing values are listed as -99.

GSWLC-A
GSWLC-M
GSWLC-D

σ(M*)

σ(M*)

Figure 6. Mean random error of SED fitting SFR (thick lines) and stellar
mass (thin lines) as a function of SSFR and UV survey depth. The second
moment of the parameter probability distribution function is adopted as theerror of these parameters

To review, the criteria for inclusion in the catalog are for
an SDSS object to be covered by GALEX observations of acertain depth, regardless of whether it was detected in the UV.
Furthermore, galaxies need to lie in 0.01 < z < 0.30 redshift
range and be above rpetro = 18.0 magnitude threshold.
Approximately 1% of SDSS targets have spectra classified
as “quasars” (CLASS = 1), based on the Balmer emission
lines being broad. These galaxies are therefore likely to beType 1 AGN, which includes Seyfert 1s, and, less frequently,true quasars. In Type 1 AGN the accretion disk is not entirely
obscured and can contribute to the UV/optical continuum of

the host, which may significantly bias the derived SED parameters, especially the SFR. This is confirmed by the findingthat the geometric mean of the reduced 2 values of the bestfitting model of broad-emission line galaxies is 4 times higher
than of other galaxies. We flag such objects in the final catalog
and do not report their SED-fitting parameters. Type 1 AGN
are not obscured by dusty torus, which is why they mostly
contribute to the UV/optical SED. We thus leave their mid-IR
SFRs in the catalog, but they should still be used with caution
in case there is some AGN emission in the mid IR.
We produce three separate catalogs, GSWLC-A, M, and D,according to the UV depth, as described in Section 2.2. In
addition, we produce a master catalog that combines the threecatalogs, keeping for each galaxy the data from the deepest
catalog. This catalog is designated GSWLC-X, and contains
658,911 objects. Readers are cautioned that non-uniform
depth may lead to systematics in SFRs, especially for galaxies
with log SSFRSED < -11 where the UV detection rate and theresulting quality differ from survey to survey (Figure 6). On
the other hand, the stellar masses will not be subject to any
such biases. All catalogs have the same format as describedin Table 1.
The catalogs are currently publicly available at http://pages.iu.edu/~salims/gswlc, which will document any changes implemented in subsequent versions. Thecatalog letter designation is followed by a version number.
The analyses in this paper are all based on Version 1 catalogs (e.g., GSWLC-M1). GSWLC is also hosted at Mikulski
Archive for Space Telescopes (MAST) and may be includedin SDSS SciServer and/or hosted by NED/IPAC in the future.
In Figure 6 we show mean random errors of log SFRSED and