GCN Circular 30618
Subject
GRB 210807A: Swift/UVOT Detection
Date
2021-08-08T21:07:25Z (3 years ago)
From
Sam LaPorte at PSU <sjl5346@psu.edu>
GRB 210807A: Swift/UVOT Detection
S. J. LaPorte (PSU) and A. Y. Lien (GSFC/UMBC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210807A
210 s after the BAT trigger (Lien et al., GCN Circ. 30600).
A source consistent with the XRT position
(Lien et al. GCN Circ. 30600)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 05:06:43.89 = 76.68289 (deg.)
Dec (J2000) = +58:14:59.2 = 58.24979 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric
system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures
are:
Filter T_start(s) T_stop(s) Exp(s) Mag
b 489 683 38 >17.84
u 639 659 19 >17.04
v 390 583 39
16.58+-0.25
uvw1 440 633 38 >17.12
uvw2 539 721 26 >17.08
white 234 383 147
16.93+-0.04
white 234 708 184 17.19+-0.05
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.409 in the direction of the burst
(Schlegel et al. 1998).