[vsnet-grb-info 15222] GRB 140703A: P60 observations of a red, slowly-fading afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16514
SUBJECT: GRB 140703A: P60 observations of a red, slowly-fading afterglow
DATE:    14/07/03 16:51:02 GMT
FROM:    Daniel Perley at Caltech  <dperley at astro.caltech.edu>

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

We observed the afterglow of GRB 140703A (Kocevski et al., GCN 16503) 
with the Palomar 60-inch (P60) robotic telescope.  We acquired 3x180s in 
each of the r, i, and z filters between 08:40:37 and 09:11:02 on 
2014-07-03 UT.  We measure the following magnitudes:

    r = 20.03 +/- 0.02   t_mid = 0.3462 days
    i = 19.46 +/- 0.02   t_mid = 0.3380 days
    z = 18.99 +/- 0.05   t_mid = 0.3533 days

This indicates very little fading since the observations of Cunniffe et 
al. (GCN 16504) and Ciabattari et al. (GCN 16511).  However, the 
spectroscopy of Castro-Tirado et al. (GCN 16505) confirms this source is 
the GRB afterglow.

We note that the afterglow color is fairly red (beta~2.2 after 
correction for foreground extinction), possibly indicating significant 
dust obscuration in the host frame.