GCN Circular 2573

Subject

GRB040422: optical and NIR observations at the VLT

Event

Date

2004-04-22T16:39:15Z (22 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 2572Loading...
 
 ), 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.

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