[vsnet-grb-info 20759] GRB 180626A: Swift/UVOT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22857
SUBJECT: GRB 180626A: Swift/UVOT Detection
DATE:    18/06/26 15:22:56 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld at ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and P. A. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180626A 
123 s after the BAT trigger (Evans et al., GCN Circ. 22850).
A fading source consistent with the XRT position (Osborne et al. GCN 
Circ. 22852) and also seen by Martone et al. (GCN Circ. 22854) and Troja 
et al. (GCN Circ. 22855) is detected in the initial UVOT exposures.

Preliminary detections and 3-sigma upper limits using the UVOT 
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for 
the finding chart (FC) and early exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white_FC           123          273          147         20.57 ± 0.22
white              633         1033          190        >21.4
v                  665         6473          452        >20.2
b                  591         5858          246        >20.4
u                  336         6936          529        >20.7
w1                 714         6882          432        >21.0
m2                5043         6677          393        >20.1
w2                 641         6268          432        >21.3

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.04 in the direction of the 
burst (Schlegel et al. 1998).