[vsnet-grb-info 16872] GRB 150817A: P60 Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18153
SUBJECT: GRB 150817A: P60 Observations
DATE:    15/08/18 13:30:21 GMT
FROM:    S. Bradley Cenko at NASA/GSFC  <brad.cenko at nasa.gov>

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

We observed the location of GRB150817A (D’Elia et al., GCN 18143) with the robotic Palomar 60 inch telescope (P60).  Observations began at 3:35 UT on 2015 Aug 17 (~ 90 min after the Swift trigger time).  We detect a faint source at the location of the (second) candidate optical afterglow from RATIR (Butler et al., GCN 18145).  Using nearby point sources from the APASS survey, we measure an i-band magnitude of 21.42 +/- 0.11 in a stacked frame at a median epoch of dt = 125 min after the Swift trigger.