GCN Circular 21806
Subject
GRB 170903A: Swift/UVOT Upper Limits
Date
2017-09-04T11:02:08Z (7 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
A. A. Breeveld (UCL-MSSL) and C. B. Markwardt (NASA/GSFC) report on
behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170903A
3484 s after the BAT trigger (Markwardt et al., GCN Circ. 21793).
No optical afterglow consistent with the XRT position (Goad et al. GCN
Circ. 21797) 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 3484 3634 147 >20.7
white 3484 4865 344 >21.6
v 3640 5275 393 >19.7
b 4460 4660 197 >20.5
u 4255 4455 197 >21.0
w1 4050 9664 362 >20.7
m2 3845 5482 393 >20.4
w2 4871 5071 197 >21.8
The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.02 in the direction of the
burst (Schlegel et al. 1998).