GCN Circular 6340
Subject
GRB070419a: Swift UVOT observations
Date
2007-04-20T21:57:46Z (17 years ago)
From
Wayne Landsman at GSFC/SSAI <landsman@milkyway.gsfc.nasa.gov>
W. Landsman and M. Stamatikos (NASA/GSFC) report on behalf of the
Swift/UVOT team
The Swift/UVOT began settled observations of GRB 070419A 115 seconds
after the BAT trigger (Stamatikos et al., GCN 6302). The afterglow
first detected by Chornock et al. (GCN 6304) is weakly detected on the
UVOT V-band image. Photometry is difficult due to the presence of a
diffraction spike from a 7th magnitude star 3' distant. The bright
star also precluded use of the UVOT broad-band white filter.
Estimated magnitudes and 3-sigma upper limits are given below:
Filter Start(s) End(s) Exposure(s) Magnitude
-----------------------------------------------------------------
V 115 515 394 20.2 � 0.3
V 869 1204 330 20.0 � 0.3
B 594 739 19 >18.7
U 569 861 58 >19.1
The magnitudes are not corrected for the Galactic reddening of E(B-V)=0.03
The V band magnitudes are consistent with a brightening noted in
previous reports (Williams et al. 6328, Wren et al. 6324, Cenko et al.
6306).