[vsnet-grb-info 16957] GRB 150902A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18238
SUBJECT: GRB 150902A: Swift/UVOT Upper Limits
DATE:    15/09/04 15:37:25 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld at ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and L. Hagen (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150902A
59510 s after the LAT trigger (Arimoto et al., GCN Circ. 18228).
No optical afterglow consistent with the XRT Source 1 position given in 
McCauley et al. (GCN Circ. 18237) is detected in the initial UVOT 
exposures. Source 2 is outside the UVOT field of view.

Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial 
exposures for source 1 are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag
white            60331        60972          631         >21.7
v                61152        61997          828         >20.3
u                59510        66787         1184         >20.7

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.40 in the direction of the 
burst (Schlegel et al. 1998).