GCN Circular 599
Subject
GRB000301C, optical R-band observations
Date
2000-03-08T15:20:28Z (25 years ago)
From
Nicola Masetti at ITeSRE,CNR,Bologna <masetti@tesre.bo.cnr.it>
S. Bernabei (Astron. Obs., Bologna), C. Bartolini, L. Di Fabrizio,
A. Guarnieri, A. Piccioni (Dip. Astronomia, Univ. of Bologna),
and N. Masetti (ITeSRE/CNR, Bologna) report:
"We have imaged the proposed optical counterpart (GCN #570) of GRB000301C
(GCN #568) on March 3, 4, 6, 7 and 8, 2000, in the R band with the 152 cm
Loiano telescope (plus EEV CCD) of the Observatory of Bologna.
Using the R magnitudes of the four comparison stars quoted by Garnavich
et al. (GCN #574) we obtain the following figures:
Date exptime seeing R mag.
---------------------------------------------------
Mar. 3.191 1000 s 2".0 20.11 +- 0.05
Mar. 4.178 2200 s 3".0 20.22 +- 0.2
Mar. 6.145 1800 s 1".7 21.60 +- 0.2
Mar. 7.135 1800 s 1".7 21.63 +- 0.15
Mar. 8.157 1800 s 1".5 21.63 +- 0.1
The R magnitudes of the first two days, albeit the measurement of March 4
was acquired under bad weather conditions (thick cirrus), seem to confirm
the deviations of the decay of this object from the typical power-law
trend seen in GRB afterglows, as already pointed out by other authors (see
GCN #581 and #586).
The present data also agree with the result reported by Boer & Veillet
(GCN #598) and indicate a "standstill" of the optical candidate. Thus,
either we are already seeing the host galaxy of this GRB (in this case it
would not be the object at 1" W, 2" N of the transient; see GCN #592,
#594, #598), or the optical transient associated to GRB000301C has a
definitely peculiar behaviour, or this is not the optical counterpart of
GRB000301C.
We also obtained B and I images which are now entering the reduction
stage.
This message is quotable.".