URAT1 Catalog Definitions

Overview

URAT is a follow-up project to the successful UCAC project using the same astrograph but with a much larger focal plane array and a bandpass shifted further to the red. Longer integration times and more sensitive, backside CCDs allowed for a substantial increase in limiting magnitude, resulting in about 4-fold increase in the average number of stars per square degree as compared to UCAC. Additional observations with an objective grating largely extend the dynamic range to include observations of stars as bright as about 3rd magnitude. Multiple sky overlaps per year result in a significant improvement in positional precision as compared to UCAC.

Detailed documentation is available in the readme and in Zacharias et al. (2015).

Name Intype Units Description
ra double deg Right Ascension at mean epoch
dec double deg Declination at mean epoch
sigs double deg position error per coordinate from scatter
sigm double deg position error per coordinate from model
nst int total number of sets the star is in
nsu int number of sets used for mean position and flag
epoch double year mean URAT observation epoch
mmag double mag mean URAT model fit magnitude
bandpass: 680-750nm
sigp double mag URAT photometry error
nsm int number of sets used for URAT magnitude
ref int largest reference star flag
0 = not a reference star
1 = o.k, both coordinates used as reference star
2 = x-coord. excluded in adjustment
3 = y-coord. excluded in adjustment
4 = x and y-coord. excluded in adjustment
5 = not selected due to astrometry flag
6 = too bright on URAT exposure (amplitude limit exceeded)
7 = no valid sigma_xy from profile fit on URAT exposure
8 = excluded by distance from URAT center (accepted field of view)
9 = excluded because outside of adopted UCAC4 magnitude range
nit int total number of images
niu int number of images used for mean position
ngt int total number of 1st order grating observations
ngu int number of 1st order grating observations used
pmr double mas/yr proper motion RA*cos(Dec) (from 2MASS)
pmd double mas/yr proper motion Dec
pme double mas/yr proper motion error per coordinate
mf2 int match flag URAT with 2MASS
1 = unique match
3 = multiple match but only 1 match with high confidence
5 = closest positional match used in case of multiple matches
7 = 2nd catalog multiple match, use closest positional match
9 = likely wrong match
11 = no match at all
mfa int match flag URAT with APASS
1 = unique match
3 = multiple match but only 1 match with high confidence
5 = closest positional match used in case of multiple matches
7 = 2nd catalog multiple match, use closest positional match
9 = likely wrong match
11 = no match at all
id2 long 2MASS star ID number
jmag double mag 2MASS J mag
ejmag double mag error in 2MASS J mag
hmag double mag 2MASS H mag
ehmag double mag error in 2MASS H mag
kmag double mag 2MASS K mag
ekmag double mag error in 2MASS K mag
iccj int CC flag for 2MASS J
0 = cc_flg 2MASS 0, no artifacts or contamination
1 = cc_flg 2MASS p, source may be contaminated by a latent image
2 = cc_flg 2MASS c, photometric confusion
3 = cc_flg 2MASS d, diffraction spike confusion
4 = cc_flg 2MASS s, electronic stripe
5 = cc_flg 2MASS b, bandmerge confusion
icch int CC flag for 2MASS H
0 = cc_flg 2MASS 0, no artifacts or contamination
1 = cc_flg 2MASS p, source may be contaminated by a latent image
2 = cc_flg 2MASS c, photometric confusion
3 = cc_flg 2MASS d, diffraction spike confusion
4 = cc_flg 2MASS s, electronic stripe
5 = cc_flg 2MASS b, bandmerge confusion
icck int CC flag for 2MASS K
0 = cc_flg 2MASS 0, no artifacts or contamination
1 = cc_flg 2MASS p, source may be contaminated by a latent image
2 = cc_flg 2MASS c, photometric confusion
3 = cc_flg 2MASS d, diffraction spike confusion
4 = cc_flg 2MASS s, electronic stripe
5 = cc_flg 2MASS b, bandmerge confusion
phqj int photometric quality flag for 2MASS J
0 = no ph_qual flag
1 = ph_qual 2MASS X, no valid brightness estimate
2 = ph_qual 2MASS U, upper limit on magnitude
3 = ph_qual 2MASS F, no reliable estimate of the photometric error
4 = ph_qual 2MASS E, goodness-of-fit quality of profile-fit poor
5 = ph_qual 2MASS A, valid measurement, [jhk]snr>10 AND [jhk]cmsig<0.10857
6 = ph_qual 2MASS B, valid measurement, [jhk]snr> 7 AND [jhk]cmsig<0.15510
7 = ph_qual 2MASS C, valid measurement, [jhk]snr> 5 AND [jhk]cmsig<0.21714
8 = ph_qual 2MASS D, valid measurement, no [jhk]snr OR [jhk]cmsig req.
phqh int photometric quality flag for 2MASS H
0 = no ph_qual flag
1 = ph_qual 2MASS X, no valid brightness estimate
2 = ph_qual 2MASS U, upper limit on magnitude
3 = ph_qual 2MASS F, no reliable estimate of the photometric error
4 = ph_qual 2MASS E, goodness-of-fit quality of profile-fit poor
5 = ph_qual 2MASS A, valid measurement, [jhk]snr>10 AND [jhk]cmsig<0.10857
6 = ph_qual 2MASS B, valid measurement, [jhk]snr> 7 AND [jhk]cmsig<0.15510
7 = ph_qual 2MASS C, valid measurement, [jhk]snr> 5 AND [jhk]cmsig<0.21714
8 = ph_qual 2MASS D, valid measurement, no [jhk]snr OR [jhk]cmsig req.
phqk int photometric quality flag for 2MASS K
0 = no ph_qual flag
1 = ph_qual 2MASS X, no valid brightness estimate
2 = ph_qual 2MASS U, upper limit on magnitude
3 = ph_qual 2MASS F, no reliable estimate of the photometric error
4 = ph_qual 2MASS E, goodness-of-fit quality of profile-fit poor
5 = ph_qual 2MASS A, valid measurement, [jhk]snr>10 AND [jhk]cmsig<0.10857
6 = ph_qual 2MASS B, valid measurement, [jhk]snr> 7 AND [jhk]cmsig<0.15510
7 = ph_qual 2MASS C, valid measurement, [jhk]snr> 5 AND [jhk]cmsig<0.21714
8 = ph_qual 2MASS D, valid measurement, no [jhk]snr OR [jhk]cmsig req.
abm double mag APASS B mag
ebm double mag error in APASS B mag
avm double mag APASS V mag
evm double mag error in APASS V mag
agm double mag APASS g mag
egm double mag error in APASS g mag
arm double mag APASS r mag
erm double mag error in APASS r mag
aim double mag APASS i mag
eim double mag error in APASS i mag
ann int APASS number of nights
ano int APASS number of observations
urat1_id int Official URAT1 star ID numbers consist of 2 parts, the 3-digit zone number (zzz) and the 6-digit running record number (nnnnnn) along a zone: zzznnnnnn