[vsnet-grb-info 3661] GRB 060901: SMARTS optical/IR observations

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5495
SUBJECT: GRB 060901: SMARTS optical/IR observations
DATE:    06/09/02 03:50:43 GMT
FROM:    Bethany Cobb at Yale U  <cobb at astro.yale.edu>

B. E. Cobb (Yale), part of the larger SMARTS consortium, reports:

Using the ANDICAM instrument on the 1.3m telescope at CTIO, we
obtained optical/IR imaging of the error region of GRB 060901
(GCN 5491, Mereghetti et al.) with a mid-exposure time of
2006-09-02 00:24:54 UT, which is ~5.7 hours post-burst.
Total summed exposure times amounted to 15 minutes in I and V and
12 minutes in J and K.

Within the error region of the X-ray afterglow detection
(GCN 5494, Racusin et al.), we detect a stellar object in 
all wavebands that is apparent in both USNO and 2MASS.
  
Additionally, in the J-band observation there is a very 
marginal detection of a source inside the X-ray error region at:

RA = 19:08:38.2
Dec = -06:38:06.14

The nature of this source is unclear, however, because 
of the low significance of the detection and the fact 
that the object is too dim to have previously been 
detected in 2MASS.  We also do not know if the object is fading.

The approximate limiting magnitudes of our images are:
J > 18.5
K > 17.4
I > 21.2
These values are calibrated against several USNO-B1.0
stars in the I-band, and 2MASS stars in J and K.