GCN Circular 9684

Subject

GRB 090715B: Lick observations

Event

Date

2009-07-17T17:28:04Z (16 years ago)

From

Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>

D. A. Perley, J. Choi, A. Morton and M. Ganeshalingam (UC Berkeley) report:

We obtained a series of R-band exposures of the optical transient
associated with GRB 090715B  (GCN 9668Loading...
 
 , Vetere et al.; GCN 9670Loading...
 
 , Smith et
al.) at the 1-meter Nickel telescope at Lick Observatory under clear skies
and good seeing.  The transient is detected in individual frames.  We
report the following magnitudes relative to the calibration star of
Malesani et al. (GCN 9671Loading...
 
 ):

t_start(UT)  exp(s)        mag                  t-t0(hr)
06:17:06.10   120    R = 20.23 +/- 0.21           9.23
06:27:36.17   200    R = 20.27 +/- 0.16           9.41
06:31:53.21   200    R = 20.06 +/- 0.14           9.48
06:42:53.80   300    R = 20.48 +/- 0.17           9.66
06:54:57.78   300    R = 20.40 +/- 0.16           9.86
07:01:01.97   300    R = 20.39 +/- 0.20           9.96
07:07:07.30   300    R = 20.24 +/- 0.14           10.07
07:19:01.36   300    R = 20.47 +/- 0.18           10.26
07:32:15.82   300    R = 20.71 +/- 0.23           10.44

A stack of all images gives an average magnitude of R = 20.23 +/- 0.07.