GCN Circular 10374
Subject
GRB 100205A: Gemini-N + NIRI photometry
Date
2010-02-05T21:18:42Z (14 years ago)
From
Antonino Cucchiara at PSU <cucchiara@astro.psu.edu>
A. Cucchiara (PSU), D. B. Fox (PSU), N. R. Tanvir (U. Leicester),
A. J. Levan (U. Warwick), B. E. Cobb (UC Berkeley), E. Berger
(Harvard/CfA),
and R. Chornock (Harvard/CfA) report on behalf of a larger collaboration:
We have calibrated the JHK photometry for the candidate Gemini-N + NIRI
afterglow (Tanvir et al., GCN 10366) of GRB 100205A (Racusin et al.,
GCN 10361) against two 2MASS stars in the field. Converted to AB
magnitudes we find:
J_AB > 23.37 mag (1-sigma UL)
H_AB = 23:54 +- 0.22 mag
K_AB = 21.91 +- 0.20 mag
Thus, based on our photometry we measure a red K-H color, K_AB - H_AB =
1.6 +- 0.5 mag.
If this red color is due to Lyman-alpha absorption within the H filter
bandpass, then
this would imply a redshift of 11 <~ z <~ 13.5. In this connection, we
note that we are
retracting our earlier claim of a J-band detection (Tanvir et al., GCN
10366) at the
candidate position.
Lower-redshift solutions with significant local (host) extinction,
unusual afterglow
colors, or substantial contributions from an underlying host galaxy
cannot be
excluded at this time.