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GCN Circular 30730

Subject
GRB 210824A: Swift/UVOT Upper Limits
Date
2021-08-27T15:52:44Z (3 years ago)
From
Sam LaPorte at PSU <sjl5346@psu.edu>
GRB 210824A: Swift/UVOT Upper Limits

S. J. LaPorte (PSU) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 210824A
311 s after the BAT trigger (Page et al., GCN Circ. 30700).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 30702)
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

white_FC           311          461          147         >20.8
white              311         4350          364         >20.9
v                  467         4760          236         >19.4
b                  565         4145          235         >20.1
u                  541         5220           83         >19.6
w1                 516         5170          236         >20.4
m2                4765         4965          197         >20.3
w2                4356         4555          197         >19.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.037 in the direction of the burst
(Schlegel et al. 1998).
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