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GCN Circular 14660

GRB 130515A: Swift/UVOT Upper Limits
2013-05-15T14:16:02Z (11 years ago)
Samantha Oates at MSSL <>
S. R. Oates (MSSL-UCL), M. De Pasquale (MSSL-UCL) and D. Malesani (DARK/NBI)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 130515A
79 s after the BAT trigger (Malesani et al., GCN Circ. 14650).
In the intial UVOT exposures, we do not detect an optical afterglow consistent
with the refined XRT position (Beardmore et al. GCN Circ. 14654). We also do not
detect an optical source consistent with the positions of s1 and s2 reported by the VLT
(Xu et al. GCN Circ. 14653) and Gemini (Cenko et al., GCN Circ. 14656),
nor at the positions of the sources reported by GROND (Schmidl et al., GCN Circ. 14655).
However, we do marginally detect VLT s3 (Xu et al. GCN Circ. 14653) in white
at a magnitude of 21.59 +/- 0.39, which is also observed in the DSS.

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 at the refined
XRT position are:

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

white_FC            79          229          147         >21.2
u_FC               291          541          246         >20.2
white               79         6414          580         >21.7
v                  620         5388          236         >19.8
b                  546         6209          432         >21.0
u                  291         6003          659         >20.7
w1                 669         5798          413         >20.7
m2                 645         5592          236         >20.0
w2                 596         6603          415         >20.7

The magnitudes in the table are not corrected for the
Galactic extinction due to the reddening of E(B-V) = 0.07
in the direction of the burst (Schlegel et al. 1998).
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