[vsnet-grb-info 16415] GRB 150413A: P60 photometry

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17696
SUBJECT: GRB 150413A: P60 photometry
DATE:    15/04/14 04:41:01 GMT
FROM:    Daniel Perley at Caltech  <dperley at astro.caltech.edu>

D. A. Perley (Caltech) and S. B. Cenko (GSFC) report:

The Palomar 60-inch telescope observed the location of the optical 
counterpart of GRB 150413A (Markwardt et al., GCN 17688; Ivanov et al., 
GCN 17689) starting at 03:15:21 UT on 2015-04-14.  We acquired 3x180s 
images in griz filters under good conditions.

The optical transient is well-detected in all four filters.  Calibrating 
relative to USNO stars in the field, we measure a magnitude of R = 19.1 
(+/- 0.1) mag at this time (t = 0.560 days after the BAT trigger), 
indicating significant fading since the early observations.

Further follow-up is planned.