GCN Circular 23062
Subject
GRB 180727A: Swift/UVOT Upper Limits
Event
Date
2018-07-30T18:03:24Z (8 years ago)
From
Frank Marshall at Swift/UVOT <marshall@milkyway.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC) and A. Beardmore (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180727A
77 s after the BAT trigger (Beardmore et al., GCN Circ. 23043).
No optical afterglow consistent with the enhanced XRT position
(D'Elia et al., GCN Circ. 23045)
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) exposures and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 77 227 147 >20.9
u_FC 290 303 12 >18.4
white 4280 5915 393 >21.7
v 4690 6312 379 >19.6
b 4075 5710 393 >21.2
u 5305 5505 197 >20.3
uvw1 5101 5301 197 >20.0
uvm2 4895 5095 197 >21.0
uvw2 4485 6122 393 >21.4
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).