GCN Circular 3717
Subject
Swift/UVOT photometry of GRB050730
Date
2005-07-31T20:48:41Z (20 years ago)
From
Alexander Blustin at MSSL-UCL <ajb@mssl.ucl.ac.uk>
A. J. Blustin (UCL-MSSL), S. T. Holland (GSFC/USRA), A. Cucchiara (PSU),
N. White (GSFC), D. Hinshaw (GSFC-SPSYS) on behalf of the Swift/UVOT
team report:
Swift/UVOT began observing GRB050730 at 2005-07-30T20:00:22, 119 s after
the BAT trigger (Holland et al. GCN 3704). A bright source was detected
in the genie image at 14h 08m 17.09s,-3d 46' 18.9" (Holland et al.
GCN 3704). Further analysis of data returned via the Malindi ground
station shows that this source is fading; we report the following V band
lightcurve, including detections significant at greater than 2.8 sigma:
Tmid (s) Exp (s) Magnitude
170 99.77 17.842 +/- 0.152
300 9.78 17.473 +/- 0.380
384 9.78 17.477 +/- 0.383
468 9.78 16.737 +/- 0.238
553 9.76 16.568 +/- 0.216
637 9.76 17.119 +/- 0.302
722 9.78 16.706 +/- 0.231
3978 99.77 18.274 +/- 0.259
11948 837.11 19.200 +/- 0.150
23520 835.72 20.211 +/- 0.371
35088 843.21 20.286 3-sigma upper limit
Where Tmid is the time after trigger of the mid-point of the
exposure.
Additionally the source was detected at greater than 2.8 sigma
significance in the B-band in 3 images:
Tmid (s) Exp (s) Magnitude
271 9.76 18.874 3-sigma upper limit
355 9.77 18.303 +/- 0.321
440 9.77 18.662 3-sigma upper limit
524 9.76 18.492 +/- 0.364
608 9.76 18.766 3-sigma upper limit
693 9.77 18.076 3-sigma upper limit
777 9.76 18.734 3-sigma upper limit
10164 899.77 20.447 +/- 0.208
21737 899.73 21.087 3-sigma upper limit
33309 901.43 21.126 3-sigma upper limit
There was no detection in U or in any of the UV filter exposures.
The upper limits for the summed images in these bands are:
Filter T range (s) Exp (s) 3-sigma magnitude upper limit
U 252-29724 2490.71 21.747
UVW1 238-28880 3665.12 21.98
UVM2 224-27972 3620.41 22.30
UVW2 281-34660 2765.25 22.40
where T range is the time range post-trigger over which the images
were taken.
The magnitudes are based on preliminary zero points, measured in
orbit, and will require refinement with further calibration. All
magnitudes are uncorrected for Galactic reddening.