GCN Circular 5068
Subject
GRB 060502A: Swift/UVOT source detection
Date
2006-05-03T10:35:52Z (19 years ago)
From
Tracey Poole at MSSL <tsp@mssl.ucl.ac.uk>
T. S. Poole (UCL-MSSL), and V. La Parola (INAF-IASFPA) on behalf of the
Swift/UVOT team.
The Swift/UVOT began observing the field of GRB060502 (BAT
Trigger=208169, V. La Parola, et. al, GCN 5047) at 03:04:56 UT, 84s
after the BAT trigger.
We detect a fading source with a calculated position of RA = 16:03:42.48
and Dec = +66:36:02.5 (J2000) in the V, B and White filters, and the
summed UVW1 filter. The error in the coordinates of the UVOT source is
+/- 0.56 arcsec (90% confidence). The position is 4.4 arcseconds from
the centre of the XRT error circle reported by V. La Parola, et. al,
(GCN 5054). Checks against the Digitized Sky Survey images yield no
known source at this position on the sky.
The calculated magnitudes of the first afterglow observations in the
UVOT filters are given below. The limiting magnitudes are given to a 3
sigma limit. These values are not corrected for Galactic extinction;
E(B-V) = 0.033.
Filter T_range(s) T_exp(s) Magnitude Comments
V 190-536 346 18.70 +/- 0.14 - source detection
V 5092-5292 200 20.19 - 3 sigma upper limit
B 4478-4678 200 20.04 +/- 0.16 - source detection
B 5910-6110 200 20.91 +/- 0.34 - source detection
U 4273-4473 200 20.84 - 3 sigma upper limit
U 5706-5905 200 20.78 - 3 sigma upper limit
UVW1 4069-4269 200 20.63 - 3 sigma upper limit
UVW1 5501-5701 200 20.61 - 3 sigma upper limit
UVW1 4069-5701 400 20.89 +/- 0.40 - source detection
UVM2 3864-4064 200 20.85 - 3 sigma upper limit
UVM2 5296-5496 200 21.03 - 3 sigma upper limit
UVW2 4888-5087 200 21.60 - 3 sigma upper limit
WHITE 84-184 100 18.50 +/- 0.07 - source detection
WHITE 4682-4882 200 20.53 +/- 0.20 - source detection
WHITE 6115-6314 200 21.22 - 3 sigma upper limit
Where T_range is time post-trigger, and T_exp is the exposure time of
the observation. A 6 arcsec radius was used for all filters.
When summing the two UVW1 200s exposures we see a source detection above
3 sigma. This give a z upper limit of 1.9.
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