[vsnet-grb-info 7470] GRB 090323: UVOT Detection of Afterglow
GCN Circulars
gcncirc at capella.gsfc.nasa.gov
Wed Mar 25 04:41:07 JST 2009
TITLE: GCN CIRCULAR
NUMBER: 9032
SUBJECT: GRB 090323: UVOT Detection of Afterglow
DATE: 09/03/24 19:40:58 GMT
FROM: Erik Hoversten at Swift/Penn State <hoversten at astro.psu.edu>
E. A. Hoversten (PSU) reports on behalf of the Swift UVOT team:
The Swift/UVOT began settled observations of the field of
GRB 090323 70 ks after the Fermi LAT trigger (Ohno et al., GCN 9021).
The afterglow is detected in the UVOT white filter at:
RA (J2000) 12:42:50.29
Dec (J2000) 17:03:11.8
with an estimated uncertainty of 0.8 arcsec (radius, 90% confidence).
This position is consistent with the UVOT enhanced XRT position (Kennea
et al., GCN 9024) as well as the optical position determined by
GROND (Updike et al., GCN 9026) The afterglow candidate does not
appear in the DSS images. Photometry from the second set of Swift
observations may be indicative of fading, but is not deep enough to be
conclusive.
UVOT magnitudes and 3-sigma upper limits are reported in the following
table:
Filter T_start T_stop Exp(s) Mag (3-sigma upper limit)
-----------------------------------------------------
WHITE 70287 75931 1196 21.66 +/- 0.28
WHITE 115572 121460 601 > 21.60
V 70667 76062 517 > 19.88
U 69906 75078 1200 > 21.02
The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight of E(B-V) = 0.03 mag.
All photometry is on the UVOT photometric system described in Poole et al.
(2008, MNRAS, 383, 627).
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