[vsnet-grb-info 18273] GRB 160716A: Swift/UVOT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19721
SUBJECT: GRB 160716A: Swift/UVOT Detection
DATE:    16/07/18 00:25:59 GMT
FROM:    Lea Hagen at PSU  <lea.zernow.hagen at gmail.com>

L. M. Z. Hagen (PSU) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160716A
88 s after the BAT trigger (Hagen et al., GCN Circ. 19716). A source
consistent with the XRT position (Evans et al., GCN Circ. 19717) is
detected in the initial UVOT exposures in the white filter. The source
has marginal evidence for fading but is not seen in the Digitized Sky
Survey (DSS), so it is unclear at this time whether it is the optical
afterglow. 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               88          773          183          19.93+-0.23
white             6218         6418          196          20.47+-0.35
white            24012        98905          490          20.62+-0.25
v                  631          651           19         >17.58
b                  556          750           38         >18.95
u                  301          725          265         >19.63
uvw1               681          701           19         >17.48
uvm2               656          676           19         >17.10
uvw2               607          627           19         >17.52


The magnitudes in the table are not corrected for the Galactic extinction
due to the large, but uncertain, reddening of E(B-V) = 1.47 in the
direction of the burst (Schlegel et al. 1998).