[vsnet-grb-info 14129] GRB 131103A: Swift/UVOT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15443
SUBJECT: GRB 131103A: Swift/UVOT Detection
DATE:    13/11/04 15:51:58 GMT
FROM:    Frank Marshall at GSFC  <femarsha at khamseen.gsfc.nasa.gov>

N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), and J. R. Cummings (NASA/UMBC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 131103A
87 s after the BAT trigger (Cummings et al., GCN Circ. 15440).
A decaying source consistent with the XRT position  (Goad et al. GCN Circ. 15442)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  23:15:40.55 = 348.91894 (deg.)
    Dec (J2000) = -44:38:25.4  = -44.64040 (deg.)
with an estimated uncertainty of 0.60 arc sec. (radius, 90% confidence).

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               87          237          147         19.41 +/- 0.13
white            19290        19893          599         21.45 +/- 0.17
v                  629        12543         1173        >20.0
b                  554        25509         1664         21.64 +/- 0.23
u                  299          549          246         18.93 +/- 0.13
w1                 678        24073         1116        >20.6
w2                6741         6941          197        >19.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).