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GCN Circular 29841

Subject
GRB 210419A: Swift/UVOT Upper Limits
Date
2021-04-20T15:49:41Z (3 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) and S. L. Laha (GSFC/UMBC/CRESST)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 210419A
136 s after the BAT trigger (Laha et al., GCN Circ. 29828).
No optical afterglow consistent with the XRT position
(Osborne et al., GCN Circ 29830)
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           136          286          147         >18.1
u_FC               294          544          246         >17.9
white              136         1027          333         >18.1
v                  627         1079           58         >17.5
b                  550          746           39         >17.7
u                  294          721          265         >17.9
w1                 677          871           39         >17.8
m2                 651         1103           58         >18.3
w2                 119         1053           67         >19.3

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.075 in the direction of the burst
(Schlegel et al. 1998).
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