GCN Circular 19346
Subject
GRB 160422A: Swift/UVOT Afterglow Confirmation
Date
2016-04-26T02:00:23Z (8 years ago)
From
Frank Marshall at GSFC <femarsha@khamseen.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 160422A
32624 s after the LAT trigger (Yassine et al., GCN Circ. 19329).
The optical afterglow candidate (Marshall, GCN Circ. 19333)
has faded in a later observation in the same filter.
Its positional consistency with the XRT source
(Maselli et al. GCN Circ. 19334) and its fadiing
behavior confirm that it is the optical afterglow of GRB 160422A.
The preliminary UVOT position is:
RA (J2000) = 02:48:22.78 = 42.09493 (deg.)
Dec (J2000) = -57:52:30.4 = -57.87512 (deg.)
with an estimated uncertainty of 0.45 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 33427 34064 627 19.50 � 0.05
white 44903 44701 785 19.91 � 0.06
v 39970 45820 320 19.29 � 0.23
u 32624 33420 783 19.09 � 0.10
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).