TITLE:   GCN CIRCULAR
NUMBER:  15761
SUBJECT: GRB 140129A: P60 optical afterglow detection
DATE:    14/01/29 04:15:45 GMT
FROM:    Daniel Perley at Caltech  <dperley@astro.caltech.edu>

D. A. Perley (Caltech) and S. B. Cenko (NASA/GSFC) report on behalf of a 
larger calibration:

The Palomar 60-inch telescope automatically responded to the Swift 
trigger for GRB 140129A (Melandri et al., GCN 15760) and began taking 
images at 03:27:37.8 UT, about 3.6 minutes post-GRB trigger.

We detect a bright source, not present in USNO B1.0, at the following 
location consistent with the Swift XRT and UVOT error circles:

RA  =  02:31:33.78
dec = -01:35:42.88
(J2000)

The source is detected in r, i, and z filters, and fades rapidly from 
r=16.29 to r=19.44 between UT 03:28 and 04:07.