Merged Catalog bit mask

Sources are matched against a list of external catalogs. The MergedCatMask column in the source catalogs contains information on such matches. This is a 32-bit flag, in which each bit corresponds to a different catalog, and this bit is open if the source has a counterpart in this external catalog.

The bit mask catalog description

Catalog name	Bit index	Search radius ['']	Description
GAIADR3	0	2	GAIA-EDR3
unWISE	1	3	unWISE (Schlafly et al. 2019)
TMASS	2	3	2MASS (Skrutskie et al. 2006)
GLADEp	3	10	GLADE
PGC	4	10	PGC galaxy catalog (Paturel et al. 1989)
SDSSDR10	5	2	SDSS-DR10 sources
PS1	6	2	PS1-DR1
DECaLS	7	2	DECaLS-DR4
GALEX	8	4	GALEX
FIRST	9	5	FIRST
NVSS	10	15	NVSS
VLASSep1	11	5	VLASS epoch 1 (Lacy et al. 2020)
LAMOST_DR4	12	2	LAMOST-DR4
NEDz	13	10	NED
SpecSDSSDR17	14	10	SDSS spectroscopy DR14
ROSATfsc	15	30	ROSAT faint source catalog
XMM	16	10	XMM
ztfDR1var	17	2	Variable sources ZTF-DR1
WDEDR3	18	2	WD
QSO1M	19	3	QSO
GAIADR3extraGal	20	10	GAIA-DR3 extragalactic (GAIA coolaboration et al. 2022)