GCN Circular 1298
Subject
GRB 020322 optical observation
Date
2002-03-23T11:13:57Z (22 years ago)
From
Jochen Greiner at Astrophys.Inst. Potsdam,Germany <jgreiner@aip.de>
J. Greiner (MPE Garching, AIP Potsdam),
U. Thiele (MPIA Heidelberg, Calar Alto),
S. Klose (Thueringer Landessternwarte Tautenburg),
A.J. Castro-Tirado (LAEFF-INTA, Madrid, and IAA-CSIC, Granada) report:
We have imaged the location of GRB 020322 with the 3.5 m telescope
at Calar Alto (Spain) for three times 10 min. between 22 Mar 2002 23:46 UT
to 23 Mar 2002 00:09 UT at a seeing of 1.4 arcsec. Based on the same USNO
star at 18:00:58.03, +81:06:08.3 listed as having R=17.5 mag we measure
the following magnitudes for the three sources a, b, c (Bloom et al.; GCN 1296)
inside the XMM error circle (Ehle et al.; GCN 1293):
Calar Alto earlier measurement
---------------------------------------------------------------------
a 22.07 +- 0.06 mag 21.9 mag (Szentgyorgyi et al; GCN 1295)
b 23.80 +- 0.30 mag 23.26 +- 0.32 mag (Bloom et al.; GCN 1294)
c 24.50 +- 0.60 mag
While object c is at our detection threshold, object b has clearly faded,
as also a visual comparison with the FITS image of Bloom et al. (GCN 1296)
shows (though the errors formally allow for constancy of source b).
We therefore suggest that source b is the optical counterpart of GRB 020322.