GCN Circular 2573
Subject
GRB040422: optical and NIR observations at the VLT
Date
2004-04-22T16:39:15Z (20 years ago)
From
Daniele Malesani at SISSA-ISAS,Trieste,Italy <malesani@sissa.it>
D. Malesani (SISSA, Trieste), D. Fugazza, G. Ghirlanda (INAF, Brera), on
behalf of a larger international collaboration involved in the Swift
mission, report:
We observed the error box of the INTEGRAL GRB040422 (Mereghetti et al.,
GCN 2572), starting 2 hours after the burst. Observations were performed
at ESO-Paranal, with an excellent seeing of ~0.5". Optical photometry
(in the R and I filters) were acquired with VLT+FORS2, while NIR K-band
imaging was performed with VLT+ISAAC. Four exposures were needed to
cover the entire INTEGRAL error box in the infrared.
We find no obvious sources after comparison of our images with the 2MASS
catalog. The limit for the 2MASS is estimated to be K < 14.5 (Skrutskie
2001, AAS #198, 33, 827). We estimate our limiting magnitude to be K =
18.5 based on the 2MASS calibration.
Further observations are planned tonight at ESO, in order to search for
variable sources. Our images are available upon request.
We thank the ESO staff at Paranal, and in particular Nancy Ageorges and
Leonardo Vanzi, for quickly performing the observations.
This message may be cited.