[vsnet-grb-info 4711] GRB 070518: optical observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6458
SUBJECT: GRB 070518: optical observation
DATE:    07/05/23 15:53:05 GMT
FROM:    Giuseppe Greco at U Bologna  <giuseppe.greco2 at studio.unibo.it>

F. Terra (Second University of Roma "Tor Vergata"), G. Greco, C. Bartolini,
A. Guarnieri, A. Piccioni (Bologna University), G. Pizzichini (INAF/IASF
Bologna), D. Nanni (INAF/OAR and Second University of Rome "Tor Vergata"),
S. Karpov (Special Astrophysical Observatory, Russia),
S. Galetti and R. Gualandi  (Bologna Observatory) report:


During the night of 07/05/18 we observed the OT of GRB070518
(Guidorzi et al., GCN 6415) with the 1.52 cm telescope 
of the Bologna Observatory in Loiano under moderate 
sky conditions (seeing ~ 2"). 
The OT flux was slightly blended with a nearby star (R ~ 18.7).
To correct for the blending we employed difference image analysis techniques.

By adding two consecutive 30 min exposures in the Rc filter at
mean time 23.5 UT we find Rc = 22.3 +/- 0.2 based on the USNO-A2.0 catalog.

Our coadded image have been posted in our public directory 
from where they can be retrieved by sftp using 
hostname: ermione.bo.astro.it
username: publicGRB
password: GRB_bo.