[vsnet-grb-info 3020] GRB 060306: SOAR Ks Observations

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4857
SUBJECT: GRB 060306: SOAR Ks Observations
DATE:    06/03/10 20:39:30 GMT
FROM:    Melissa Nysewander at UNC,Chapel Hill  <mnysewan at physics.unc.edu>

M. Nysewander, D. Reichart, A. Oliveira, P. Ugarte, and A. Alvarez report
on behalf of the UNC team of the FUN GRB collaboration:

We observed the localization of GRB 060306 (Angelini et al., GCN 4848) with
the SOAR infrared imager, OSIRIS, beginning at 00:31:56 UT on March 7th,
1.0 days after the burst.  We detect no new source down to a 3-sigma
limiting magnitude of Ks = 18.2 based on six stars from the 2MASS
catalogue.

If one assumes minimal extinction in the Ks band and uses the extrapolated
to 24 hours, unabsorbed X-ray flux of Page et al. (GCN 4850), this suggests
a NIR to X-ray spectral index that is shallower than -0.7.

The source in the XRT error circle which is also in the DSS-Red plate (as
noted by Price et al., GCN 4854) is at Ks = 17.3 +/- 0.2 mag.

SOAR is currently being commissioned.