GCN Circular 2471

GRB 031203: IR NTT observations do not confirm REM detection

F.M. Zerbi, G. Chincarini,  S. Covino, E. Molinari, A. Di Paola, D. 
Fugazza,
V. Testa, M. Rodono', L.A. Antonelli,  P. Conconi, G. Cutispoto,
L. Nicastro, G. Tosti, L. Burderi, S. Campana, C. Campeggi, G. Crimi,
R. Cunniffe, J. Danzinger, A. Fernandez-Soto, F. Fiore,  F. Frontera,
G. Gentile, G. Ghisellini, P. Goldoni, G. Israel, B. Jordan, D. Lazzati,
D. Lorenzetti,  D. Malesani, E. Martinetti, N. Masetti, R. Mazzoleni,
B. Mc Breen, A. Melandri, S. Messina, E. Meurs, A. Monfardini,
G. Nucciarelli, M. Orlandini, J. Paul, E. Palazzi, E. Pian,
P. Saracco, S. Sardone, A. Simoncelli, M. Stefanon, L. Stella,
L. Tagliaferri, M. Tavani, G. Tosti, S. Vergani, F. Vitali.



We observed in JHKs filters with SofI at the NTT telescope the field of the
INTEGRAL GRB 031203 (Gotz et al. GCN 2459
Not found
 
 
) starting at 4 December 04h54m
UT. The object detected by the REM telescope in the H and Ks filters 
(see Zerbi
et al. GCN 2466
Not found
 
 
) was not detected in these images, with upper limits of 
J=22.2,
H=21.1, Ks_1=20.9 and Ks_2=20.2 (we have two exposures in the Ks filter 
separated
by about 2.5 hours).

A reanalysis of the REM data confirmed the presence of the object reported
in GCN 2466
Not found
 
 
. We are still investigating the possible cause of it.

The object reported by Hsia et al. (GCN2470
Not found
 
 
), associated with the XMM
source S1 (Santos-Lleo & Calderon GCN2464
Not found
 
 
), is present in all SofI images,
with magnitudes J=18.2+/-0.08, H=17.35+/-0.04 and Ks_1=16.45+/-0.03
(exposure of 45 min starting at UT 04:54 and ending at UT 05:47)
and Ks_2=16.43+/-0.04 (exposure of 15 minutes starting at UT 07:30 and
ending at 07:46). Therefore, this object remained constant in the two Ks 
images.

Last night we observed the field also with the VLT telescope and the
ISAAC camera. A report on the quick analysis of these data will be
given later today.