GCN Circular 29629
Subject
GRB 210307A: Swift/UVOT Upper Limits
Date
2021-03-08T23:38:27Z (3 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) and E. Ambrosi (INAF-IASFPA)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210307A
100 s after the BAT trigger (Ambrosi et al., GCN Circ. 29610).
No optical afterglow consistent with the XRT position
(Ambrosi et al. GCN Circ. 29610)
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 100 250 147 >20.9
u_FC 313 562 246 >20.6
white 100 786 186 >21.1
v 642 836 39 >19.3
b 568 761 39 >19.9
u 313 736 265 >20.6
w1 692 711 19 >19.6
m2 667 687 19 >18.7
w2 618 812 39 >19.9
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.138 in the direction of the burst
(Schlegel et al. 1998).