GCN Circular 21353
Subject
Correction to GCN Circular 21351: GRB 170714A: Swift/UVOT Observations
Date
2017-07-17T21:37:38Z (8 years ago)
From
Frank Marshall at GSFC <femarsha@khamseen.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC)
reports on behalf of the Swift/UVOT team:
Some of the Swift UVOT exposures of GRB 170714A
previously reported by Marshall and D'Ai (GCN Circular 21351)
contain readout streaks due to nearby bright sources.
These streaks make the determination of magnitudes very difficult,
and this effect was not accounted for in the previous analysis.
The affected exposures have been removed from the corrected
table given below. As a result, the most significant detection
of a source with UVOT has been removed, and there is now
only weak evidence for a UVOT source at the position of
the z-band afterglow candidate reported by
de Ugarte Postigo et al. (GCN Circ. 21346).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
v 397 1695 175 >18.6
b 496 1644 155 20.0 +/- 0.33
b 92917 93309 382 >20.3
u 471 1619 284 20.1 +/- 0.35
u 81432 92912 1509 >20.7
w1 446 1594 136 >21.0
m2 76276 98985 2438 >21.3
w2 74458 86274 1771 >21.5
I apologize for any confusion caused by the earlier report.