[vsnet-grb-info 2020] GRB050822: Swift/UVOT upper limits

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3859
SUBJECT: GRB050822: Swift/UVOT upper limits
DATE:    05/08/22 20:10:52 GMT
FROM:    Alexander Blustin at MSSL-UCL  <ajb at mssl.ucl.ac.uk>

M. J. Page, H. Ziaeepour, A. J. Blustin (UCL-MSSL), M. Chester (PSU),
R. Fink (GSFC), N. Gehrels (GSFC) on behalf of the Swift UVOT team

The Swift/UVOT began observing the field of GRB050822 at 03:51:47,
138 s after the BAT trigger (Blustin et al., GCN 3849). No new source
(with respect to the DSS image) is observed at the XRT position in
summed images from any of the six filters down to the following
3-sigma magnitude upper limits:

Filter  T_range (s)  Exp (s)  3-sig UL (mag)

V       138-1090     278      19.5
B       284-1453     135      19.7
U       270-1402     188      19.4
UVW1    257-1298     188      20.0
UVM2    242-1194     188      20.6
UVW2    300-986      88       20.0

Where T_range is the time range post-trigger over which images were
co-added.

The magnitudes have not been corrected for extinction. These
magnitudes are based on preliminary zero-points, measured in orbit,
and will require refinement with further calibration.