GCN Circular 19322

Subject
GRB 160417A: Swift/UVOT Detection
Event
Date
2016-04-17T18:40:24Z (10 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
A. A. Breeveld (UCL-MSSL) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160417A
136 s after the BAT trigger (D'Avanzo et al., GCN Circ. 19316Loading...
 
 ).
The source reported for the UVOT in the initial GCN and also by Zheng 
and Filippenko (GCN Circ. 19317Loading...
 
 ) is found to be fading.

The preliminary UVOT position is:
     RA  (J2000) =  08:01:01.64 = 120.25685 (deg.)
     Dec (J2000) = +07:39:46.4  =   7.66289 (deg.)
with an estimated uncertainty of 0.46 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

white              136          285          147         18.92 �� 0.07
white              870         1020          147         19.14 0.10
v                  623         1070           58         18.54 �� 0.31
b                  549         1169           58         19.07 �� 0.21
u                  294          543          246         18.08 �� 0.08
w1                 672         1280           64        >18.9
m2                 647         1268           78        >19.1
w2                 599         1220           78        >18.8

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).