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GCN Circular 14425

GRB 130420B: Swift/UVOT Upper Limits
2013-04-20T21:28:15Z (11 years ago)
Massimiliano de Pasquale at MSSL-UCL <>
M. De Pasquale, S. R. Oates (MSSL-UCL) reports on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 130420B
57 s after the BAT trigger (Oates et al., GCN Circ. 14411).
No optical afterglow consistent with the XRT position (Page et al., GCN
14421) is detected in the initial and summed UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) are:

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

white               57         5841          460         >21.7
v                 4707         4907          197         >19.6
b                 4091         5727          393         >20.9
u                 3886         5521          393         >20.6
w1                5117         5317          197         >20.1
m2                4912         5111          197         >19.8
w2                4502         4702          197         >20.1

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).
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