GCN Circular 17872
Subject
GRB 150523A: Swift/UVOT Detection
Event
Date
2015-05-26T17:15:00Z (11 years ago)
From
Frank Marshall at GSFC <femarsha@khamseen.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC) and A. Vargas (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150523A
32968 s after the LAT trigger (Bissaldi et al. GCN Circ. 17864).
A source consistent with the XRT position (Beardmore et al. GCN Circ. 17866)
and the optical afterglow position (Dichiara et al. GCN Circ. 17868 and 17869)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 07:41:08.67 = 115.28613 (deg.)
Dec (J2000) = -45:25:12.4 = -45.42011 (deg.)
with an estimated uncertainty of 0.78 arc sec. (radius, 90% confidence).
Preliminary detections 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
white 33590 39627 1150 21.83 +/- 0.24
v 34212 40619 1433 >20.5
u 32968 44748 2077 >20.5
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.30 in the direction of the burst
(Schlegel et al. 1998).