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GCN Circular 22464

GRB 180305A: Swift/UVOT Upper Limits
2018-03-06T18:03:54Z (6 years ago)
Sam Emery at MSSL-UCL <>
S.W.K. Emery (MSSL-UCL) and M. H. Siegel (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180305A
30621 s after the Fermi/LAT trigger (Axelsson et al., GCN Circ. 22457).
No optical afterglow consistent with the enhanced XRT position
(D'Avanzo et al., GCN Circ. 22462)
or the RATIR and Mondy detections (Troja et al., GCN Circ. 22460;
 Mazaeva et al., GCN Circ. 22463)
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) in the
initial exposures are:

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

white            30808        52964          961         >21.4
u                30621        52533         2623         >20.7
v                30994        48392          712         >19.5

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.454 in the direction of the burst
(Schlegel et al. 1998).
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