[vsnet-grb-info 7732] GRB090429B: Gemini-N infrared IR candidate

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9286
SUBJECT: GRB090429B: Gemini-N infrared IR candidate
DATE:    09/04/29 10:45:17 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara at astro.psu.edu>

A. Cucchiara (PSU), A. Levan (U. Warwick), N. Tanvir (U. Leicester),
D. B. Fox (PSU) and E. Berger (Harvard U.) report:

"On April 29.35 UT we imaged the field of Swift GRB 090429 (Ukwatta et
al., GCN 9281) with NIRI on the Gemini-North telescope.  We obtained
images in J,H and K for a total exposure time of 9, 4.5 and 9 minutes
respectively.
In the coadded images we identify a possible IR counterpart inside the
XRT error circle at the coordinates:

RA (J2000): 14:02:40.05
Dec (J2000): +32:10:14.32

with an uncertainty of 0.5".

The estimated magnitude are:

J = 21.79 +- 0.1
H = 20.08 +- 0.05
K = 19.15 +- 0.03

These values are calibrated using the 2MASS star at RA=14:02:42.20,
Dec= +32:10:50.36.

Although variability remains to be confirmed, the red J-H colour,
coupled with the relatively blue (H-K) is suggestive of a break.
Although this may be caused by dust the lack of apparent excess N_H in
the X-ray spectrum (GCN 9281) suggests this may not be the case.
Hence GRB 090429B should be considered a high-z candidate."
 
We thank the Gemini-N staff for the support in performing this
observations, in particular Scott Fisher and Kathy Roth."