GCN Circular 9730
Subject
GRB 090728: Swift/UVOT Upper Limits
Date
2009-07-28T22:58:42Z (15 years ago)
From
Patricia Schady at MSSL/Swift <msslba@googlemail.com>
GRB 090728: Swift/UVOT Upper Limits
P.A. Curran (MSSL-UCL), V. Mangano (INAF-IASFPA), report on behalf of
the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 090728
117s after the BAT trigger (Mangano et al., GCN 9725). No optical
afterglow consistent with the refined XRT position (Osborne et al., GCN
9729) or the optical counterpart (Melandri et al. , GCN 9726) is
detected in the UVOT exposures. This is consistent with the R-band
non-detection of Melandri et al.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) for the initial finding chart (FC)
and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
v 422 6883 479 > 20.70
b 372 6643 491 > 21.45
u 117 366 150 > 20.00 (FC)
u 117 6437 842 > 21.34
uw1 472 6233 452 > 21.05
um2 447 6026 452 > 20.75
uw2 398 6849 490 > 20.89
The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.07 in the direction of the burst
(Schlegel et al. 1998).