GCN Circular 9527
Subject
GRB090618: Swift/UVOT bright afterglow detection
Date
2009-06-18T19:00:10Z (15 years ago)
From
Patricia Schady at MSSL/Swift <ps@mssl.ucl.ac.uk>
P. Schady (MSSL-UCL) reports on behalf of��the Swift UVOT team:
The Swift/UVOT began settled observations of the field of GRB 090618 129s
after the BAT trigger (Schady et al., GCN Circ. 9512) and a
decaying��source is detected in all UVOT filters at the position reported
in Schady et al. (GCN Circ. 9512), consistent with refined XRT error
circle��(Evans et al., GCN Circ. 9521) as well as the optical afterglow
position reported in a number of other GCNs (GCN Circ. 9512, 9514, 9515).
The detection of the afterglow of GRB 090618 in all filters puts��an upper
limit on the redshift��of z < 1.7, consistent with the redshift constraints
reported by Cenko et al. (GCN Circ. 9518).
The magnitudes for the first UVOT observation of GRB 090618 in each filter
are as follows:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 129 279 147 14.27+/-0.01
v 671 691 19 15.60+/-0.09
b 596 616 19 15.92+/-0.06
u 340 590 246 14.62+/-0.01
uvw1 720 740 19 15.09+/-0.08
uvm2 695 715 19 15.23+/-0.12
uvw2 647 667 19 15.27+/-0.10
The values quoted above are not corrected for the Galactic extinction due
to the reddening of E(B-V) = 0.09 in the direction of the burst
(Schlegel��et al. 1998). The photometry is on the UVOT photometric system
described��in Poole et al. (2008, MNRAS, 383, 627).