[vsnet-grb-info 14815] GRB 140419A: P60 Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16129
SUBJECT: GRB 140419A: P60 Observations
DATE:    14/04/19 20:26:32 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 (Zheng et al., GCN 16119; Guver et al., GCN 16120; Butler et al., GCN 16121; Kuin et al., GCN 16123; Hentunen et al., GCN 16126) of the Swift GRB 140419A (Marshall et al., GCN 16118) with the robotic Palomar 60 inch telescope.  Observations were obtained in the r', i', and z' filters beginning at 4:40 UT on 2014 April 19 (33 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' = 16.91 +/- 0.03 at dt = 33.7 min
i' = 16.56 +/- 0.03 at dt = 35.1 min
z' = 16.45 +/- 0.04 at dt = 36.5 min

The redder r'-i' color is consistent with the Lyman break falling in the observed r' bandpass, as reported by Tanvir et al. (GCN 16125).

Further observations are planned.