GCN Circular 20823
Subject
GRB 170306A: Swift/UVOT Upper Limits
Event
Date
2017-03-06T18:52:02Z (9 years ago)
From
Sam Emery at MSSL-UCL <samuel.emery.15@ucl.ac.uk>
S.W.K. Emery (UCL-MSSL) and C. B. Markwardt (NASA/GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170306A
140 s after the BAT trigger (Markwardt et al., GCN Circ. 20819).
No optical afterglow consistent with the XRT position
(Markwardt et al., GCN Circ. 20819)
and the optical positions
(Guidorzi et al., GCN Circ. 20820; Schady et al., GCN Circ. 20822)
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 140 290 147 >20.0
u_FC 299 548 246 >18.9
white 140 771 186 >20.4
v 629 821 39 >18.1
b 554 747 39 >18.6
u 299 722 265 >19.0
w1 678 870 39 >18.1
m2 653 846 39 >19.0
w2 604 796 39 >18.1
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.41 in the direction of the burst
(Schlegel et al. 1998).