GRB 050721
GCN Circular 3662
Subject
GRB 050721: early afterglow light curve
Date
2005-07-22T23:00:24Z (20 years ago)
From
Daniele Malesani at SISSA-ISAS,Trieste,Italy <malesani@sissa.it>
V. Testa, L.A. Antonelli (INAF/OAR), D. Malesani (SISSA), S. Covino, P.
D'Avanzo, G. Tagliaferri (INAF/OABr), G. Chincarini (Univ.
Milano-Bicocca), G.L. Israel, S. Piranomonte, L. Stella (INAF/OAR),
report on behalf of the MISTICI collaboration:
We analyzed the full dataset of the early light curve of the afterglow
of GRB 050721 (Antonelli et al., GCN 3654; Torii, GCN 3655; Covino et
al., GCN 3657), obtained with the ESO VLT in rapid response mode.
The observation, performed in the R band, started 25 min after the GRB
and lasted for 107 minutes (till the object set). It was composed by
several short (30 s), repeated exposures. The light curve is well
described by a single power law, with decay index 1.20 +- 0.01. The
decay is smooth, without any significant rebrightening or deep.
We acknowledge the excellent support provided by the ESO staff in
performing the observations.
This message can be cited.
GCN Circular 3657
Subject
GRB 050721: optical afterglow confirmed
Date
2005-07-21T06:59:54Z (20 years ago)
From
Daniele Malesani at SISSA-ISAS,Trieste,Italy <malesani@sissa.it>
S. Covino, P. D'Avanzo (INAF/OABr), S. Bagnulo, T. Szeifert (ESO), D.
Malesani (SISSA), G. Tagliaferri (INAF/OABr), G. Chincarini (Univ.
Milano-Bicocca), S. Piranomonte, L.A. Antonelli, and L. Stella
(INAF/OAR), on behalf of the MISTICI collaboration, report:
We observed the field of GRB 050721A (Antonelli et al., GCN 3654) with
the ESO-VLT UT2. Observations were carried out with the FORS1 instrument
in the R filter, starting on 2005 Jul 21, 4:54 UT (~25 minutes after the
GRB) and are still in progress.
Inside the XRT error box, we find a fiding source at the approximate
coordinates:
alpha = 16:53:44.53
delta = -28:22:51.8
with an error of ~1".
This lies 1.1" E, 0.7" N of the USNO star U0600_22125777, and is likely
the same source reported by Torii (GCN 3655).
This rapid response by an 8m-class telescope was possibile thanks to the
special Rapid Response Mode provided by ESO.
This message can be cited.