[vsnet-grb-info 9518] GRB 100725A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10989
SUBJECT: GRB 100725A: Swift/UVOT Upper Limits
DATE:    10/07/25 23:00:31 GMT
FROM:    Tyler Pritchard at PSU  <tapritchard at astro.psu.edu>

GRB 100725A: Swift/UVOT Upper Limits

T. A. Pritchard (PSU) and C. B. Markwardt (CRESST/GSFC/UMD)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 100725A
85 s after the BAT trigger (Markwardt et al., GCN Circ. 10979).
No optical afterglow consistent with the XRT position
(Evans et al., GCN Circ. 10985) is detected in the initial UVOT
exposures.  Preliminary 3-sigma upper limits using the UVOT
photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white_FC            85          234          147 >20.7
u_FC               297          547          246 >20.3
white               85        11646         1486 >21.8
v                  626        13269         1202 >20.2
b                  552         7488          440 >20.6
u                  297         7353          736 >20.5
w1                 675         7148          510 >20.4
m2                 651         6942          510 >20.3
w2                 602        12552         1396 >21.2

The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).