[vsnet-grb-info 5497] Early OT detection of XRF in NGC 2770 in Asiago frames

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7163
SUBJECT: Early OT detection of XRF in NGC 2770 in Asiago frames
DATE:    08/01/11 11:08:16 GMT
FROM:    Stefano Valenti at U di Ferrara,Italy  <valenti at fe.infn.it>

S. Valenti, M. Turatto, H. Navasardyan, S. Benetti and E. Cappellaro report:

The optical counterpart of the transient source in NGC 2270 (cfr. GCN 7159)
was present on images of SN2007uy taken with the 1.8m telescope of the Asiago
Observatory (+AFOSC) on Jan. 10.01 (10.5h after the Swift detection) and
not visible
(limit magnitude  ~ 21) on Jan.  7.00.
The transient was of mag ~ 19 in V,   fainter than SN 2007uy by 3 and 2.8
magnitude in V and R,
respectively.  Following the report of J. Deng and Y. Zhu (GCN7160) that
the transient was roughly 2 magnitudes  fainter than SN2007uy on Jan. 10.76,
in R band, it seems that the luminosity of the transient is rising
rapidly, supporting the very fortunate possibility  that Swift has
observed, in
real time, the explosion of a massive star. A image of the transient can
be found at:
http://www.eso.org/~svalenti/homepage/transient.jpg