[vsnet-grb-info 13846] GRB 130831B: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15160
SUBJECT: GRB 130831B: Swift/UVOT Upper Limits
DATE:    13/09/01 17:28:26 GMT
FROM:    Frank Marshall at GSFC  <femarsha at khamseen.gsfc.nasa.gov>

F.E. Marshall (NASA/GSFC) and D. Malesani (DARK/NBI)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 130831B
130 s after the BAT trigger (Malesani et al., GCN Circ. 15141).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 15149)
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) exposures and subsequent exposures are:

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

white_FC           130          279          147         >20.3
u_FC               288          537          246         >19.6
white              130         6384          439         >20.9
v                  618         5490          274         >19.7
b                  543         6312          274         >20.5
u                  288         6106          501         >20.3
w1                 667         5901          274         >20.2
m2                 642         5695          255         >20.9
w2                 593         5285          274         >20.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.08 in the direction of the burst
(Schlegel et al. 1998).