[vsnet-grb-info 14839] GRB 140423A: P60 Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16153
SUBJECT: GRB 140423A: P60 Observations
DATE:    14/04/23 17:09:05 GMT
FROM:    S. Bradley Cenko at NASA/GSFC  <brad.cenko at nasa.gov>

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

We observed the optical afterglow (Elenin et al., GCN 16143; Kaur et al., GCN 16144; Ferrante et al., GCN 16145; Chester et al., GCN 16147; Maehara et al., GCN 16151) of the Swift GRB 140423A (Sonbas et al., GCN 16142) with the robotic Palomar 60 inch telescope. Observations were obtained in the r', i', and z' filters beginning at 9:55 UT on 2014 April 23 (84 minutes after the Swift trigger).

The optical afterglow is clearly detected in all three filters. Using nearby point sources from SDSS for calibration, we measure the following magnitudes in our initial images:

r' = 18.87 +/- 0.05 at dt = 84.0 min
i' = 18.71 +/- 0.05 at dt = 87.0 min
z' = 18.67 +/- 0.11 at dt = 88.4 min

Further observations are planned.