GCN Circular 1561
Subject
XRF 020903: Correction to GCN 1560
Date
2002-09-30T21:32:57Z (22 years ago)
From
Daniele Malesani at Brera Astro. Obs. <malesani@merate.mi.astro.it>
M. Stefanon, S. Covino, D. Malesani (INAF, Merate Obs., Milan, I), N.
Masetti (IASF/CNR, Bologna, I.), G. Temporin (Inst. fur Astr. Innsbruck,
A), and S. Desidera (Padova Astr. Obs., I), on behalf of a larger
Italian collaboration, communicate:
We have found that the star named (2) in our previous circular (GCN
1560) was actually saturated in our images. We hence removed it from our
analysis. Here is the whole correct text.
We observed the variable source in the field of XRF 020903 (Ricker et
al., GCN 1530; Soderberg et al, GCN 1554) on 29.9 UT, with the 182cm
telescope at Cima Ekar-Asiago, near Padova (Italy). The object was at
high airmass.
We find the following magnitudes for the suspect afterglow (AG) with
respect to the USNO star (1) reported in the finding chart of Soderberg
et al. (see http://www.astro.caltech.edu/~ams/XrF.html ):
Filter UT Exposure AG - (1)
------------------------------------
V 29.923 600 sec 4.20+-0.09
R 29.931 600 sec 2.63+-0.01
I 29.937 300 sec 4.50+-0.13
In the I-band image, the object is barely visible. Using the USNO
R-magnitude for the reference star (1), R = 16.0 (star 2 is saturated),
we find
R = 18.63 +- 0.2 @29.931 UT (26.5 days after XRF),
where the error is mainly due to calibration. More accurate photometry
will be distributed when available. Our data suggest further brightening
between 28.3 and 29.9 UT, with respect to the value found in Soderberg
et al. web page.
With present data, we cannot say if the varying source is a rising
supernova or a variable radio-loud AGN, as suggested by Gal-Yam (GCN
1556). Further observations are planned tonight.
This message may be cited.