[vsnet-grb-info 12602] GRB 121108A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13962
SUBJECT: GRB 121108A: Swift/UVOT Upper Limits
DATE:    12/11/09 18:03:29 GMT
FROM:    Frank Marshall at GSFC  <femarsha at khamseen.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and T. N. Ukwatta (MSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 121108A
64 s after the BAT trigger (Ukwatta et al., GCN Circ. 13952).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 13959)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white_FC            64          213          147         >20.9
u_FC               276          526          246         >20.5
white               64         1721          412         >21.3
v                  605         1771          136         >19.6
b                  531         1697          117         >19.9
u                  276         1672          362         >20.6
w1                 655         1814          129         >19.6
m2                1429         1623           39         >19.6
w2                 581         1747          136         >19.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.37 in the direction of the burst
(Schlegel et al. 1998).