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GCN Circular 31917

Subject
GRB 220412B: Swift/UVOT Upper Limits
Date
2022-04-19T01:41:07Z (2 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 220412B
89 s after the BAT trigger (Gropp et al., GCN Circ. 31886).
No optical afterglow consistent with the BAT position
(Sakamoto et al., GCN Circ. 31910) 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 initial exposures are:

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

white (fc)          89          217          128         >20.0
white             4378         4577          197         >20.3
b                 4173         4373          197         >19.8
u                 3968         4167          197         >19.4
w2                4584         4663           78         >19.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.060 in the direction of the burst
(Schlegel et al. 1998).
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