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GCN Circular 30785

GRB 210905A: Swift/UVOT Upper Limits
2021-09-09T04:59:53Z (3 years ago)
Mike Siegel at PSU/Swift MOC <>
M. H. Siegel (PSU) and E. Sonbas (Adiyaman Univ.)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 210905A
157 s after the BAT trigger (Sonbas et al., GCN Circ. 30765).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 30768) 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 first
finding chart (FC) exposure and subsequent exposures are:

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

u_FC               157          407          246         >20.1
v                 4193         4393          197         >19.3
b                 3782         3982          197         >21.4
w1                4603         4803          197         >20.1
m2                4398         4597          197         >19.5
w2                3988         4188          197         >19.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.034 in the direction of the burst
(Schlegel et al. 1998).
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