[vsnet-grb-info 14668] GRB 140311C: Swift-XRT and UVOT observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15982
SUBJECT: GRB 140311C: Swift-XRT and UVOT observations
DATE:    14/03/13 18:05:25 GMT
FROM:    Valerio D'Elia at ASDC  <delia at asdc.asi.it>

V. D'Elia (ASDC), L.M.Z. Hagen (PSU), L. Izzo (URoma/ICRA), P.  
D'Avanzo (INAF-OAB), S. Holland (STScI) report on behalf of the Swift  
team:


We report on Swift observations of the field of the GBM discovered  
GRB140311C burst (Stanbro, GCN Circ 15977), for which a possible  
optical counterpart was reported by iPTF (Singer et al., GCN Circ  
15971).

XRT began observing the field on 2014-03-12 at 23:43:48 UT, i.e.,  118  
ks after the trigger, for a total of 2.7ks. No source is detected at  
the iPTF coordinates, nor in the whole XRT field of view. The 3-sigma  
upper limit on the count rate is 5E-03 cts/s.

The Swift/UVOT began settled observations of the field of GRB 140311C  
118480 s after the trigger. No optical afterglow consistent with the  
iPTF position (Singer et al., GCN Circ. 15971) is detected in the  
initial UVOT exposure. The preliminary 3-sigma upper limit using the  
UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358,  
373) for the initial exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag
u               118480       125414         2916        >21.43

The magnitude in the table is not corrected for the Galactic  
extinction due to the reddening of E(B-V) = 0.01 in the direction of  
the burst (Schlegel et al. 1998).  We note that the photometry may be  
affected by a nearby bright foreground star.


----------------------------------------------------------------
This message was sent using IMP, the Internet Messaging Program.