GCN Circular 18369
Subject
GRB 150925A: Swift/UVOT Upper Limits
Date
2015-09-26T03:01:53Z (9 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
M. H. Siegel (PSU) and J. L. Racusin (NASA/GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150925A
149 s after the BAT trigger (Racusin et al., GCN Circ. 18365).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 18366)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 149 298 147 >20.2
u_FC 307 557 246 >19.7
white 149 13178 1385 >21.2
v 637 7068 510 >19.7
b 563 18924 1676 >20.7
u 307 18430 2310 >20.2
w1 688 17516 1333 >20.8
m2 1589 22808 586 >21.1
w2 1019 6864 452 >19.8
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.10 in the direction of the burst
(Schlegel et al. 1998).