[vsnet-grb-info 5732] GRB080310: Super-LOTIS suggestion of brightening

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7387
SUBJECT: GRB080310: Super-LOTIS suggestion of brightening
DATE:    08/03/10 10:09:06 GMT
FROM:    Peter A. Milne at Super-LOTIS  <pmilne at as.arizona.edu>

P.A. Milne and G.G. Williams (U Arizona) report on behalf of the
Super-LOTIS team:

The 0.6m Super-LOTIS telescope began R-band observations of the error
region of GRB080310 (Swift trigger 305288) at 08:38:43 UT, 44 seconds
after the start of the burst.  The OT detected by Chornock et al.
(GCN 7381) and confirmed by Cummings et al. (GCN 7382) is not
apparent in the initial images, but is clearly visible in
subsequent images. A stack of the initial 3x10s exposures does not
detect the GRB, while subsequent single 20sec exposures do, suggesting
that the GRB brightened during the first two minutes.

We used the USNO-B star at RA=14:40:11.3, Dec==00:10:40.6 (0898-0239265) to
derive the R magnitude.

The R-band magnitude of the afterglow in the first image is:
UT Start   UT End ExpTime  R mag  error
Single
08:40:29  08:41:09 1x20s  17.97 +/- 0.18
08:41:03  08:41:23 1x20s  16.81 +/- 0.08
Stack
08:40:29  08:42:37 5x20s  16.91 +/- 0.04
08:43:24  08:54:27 10x60s 16.98 +/- 0.02

Observations are continuing.  This message can be cited.