GCN Circular 518
Subject
GRB991216, UBVRIJHK field photometry
Date
2000-01-14T19:03:19Z (25 years ago)
From
Arne A. Henden at USNO/USRA <aah@nofs.navy.mil>
A. Henden (USRA/USNO), H. Guetter and F. Vrba (USNO)
report on behalf of the USNO GRB team:
We have acquired UBVRcIc all-sky photometry for the field
of GRB991216 with the USNOFS 1.0-m telescope on four
photometric nights, but with some nights having
poor seeing. This field is reddened, with
a mean color (B-V) ~ 1.2. Because of this, many of
the fainter sources do not have U or B magnitudes. We have
therefore created two files on our anonymous ftp site:
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb991216.dat
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb991216f.dat
where the first file contains multicolor observations, and
the second file contains a smaller set of fainter stars
surrounding the OT position, but with only R magnitudes
listed. In particular, the R magnitudes we obtain for
stars A and B of Jha (GCN 476) and the comparison
star of Henden (GCN 463) agree with those obtained by
Dolan, et. al. (GCN 486) within the quoted errors.
The astrometry in these files is based on linear plate
solutions with respect to USNO-A2.0. The internal errors
are less than 100mas.
We also observed this field with the USNO IRCAM on the
1.55-m telescope on a single photometric night to obtain
JHK photometry for 6 stars near the OT position. Observations
were obtained of 11 standard stars to put the measures on the
CIT photometric system. The errors reflect uncertainties in the
in the extinction and color transformations. The data were
reduced independently in K and H magnitudes and J-H and H-K
colors:
RA (J2000) DEC K H J-H H-K
77.375279 11.288480 11.77+/-.03 11.92+/-.03 0.69+/-.03 0.19+/-.03
77.374150 11.285729 12.48 .03 12.62 .03 0.70 .04 0.19 .03
77.392377 11.290707 14.00 .04 14.19 .03 0.82 .04 0.27 .03
77.399284 11.290875 14.68 .08 14.85 .10 0.50 .10 0.25 .10
77.377129 11.297201 14.61 .07 14.65 .05 0.61 .04 0.11 .05