[vsnet-grb-info 9611] GRB 100807A: P200 Infrared Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  11080
SUBJECT: GRB 100807A: P200 Infrared Observations
DATE:    10/08/11 15:01:54 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko at srl.caltech.edu>

R. Chary and J. Davies (Caltech) report:

We have imaged the field of GRB 100807A (Grupe et al., GCN 11067) with
the WIRC instrument on the Palomar 200 inch telescope in the J and H bands
beginning at 9:47 UT on 7 August (~ 35 mins after the Swift trigger). The
fading transient reported in Cenko et al. (GCN 11073) is clearly
detected.  Using 2MASS stars for relative photometry, we measure the
following photometry for the object:

UT (mid-point)  t_burst (min)   Filter          Magnitude
---------------------------------------------------------------
09:55           41              J               19.76 +/- 0.1
10:10           56              H               19.05 +/- 0.1
12:16           183             J               21.10 +/- 0.2

The red colors of the source compared to the optical photometry can be
attributed to the A_V=2.5 mag of Galactic extinction in this region.

A nearby object 3" to the SE is also quite red with H=18.75+/-0.1 and
J-H=1.5 mag and could potentially be the host galaxy.

All magnitudes are in the Vega system.