TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  2549
SUBJECT: GRB040223: Deep NIR NTT data re-analysis
DATE:    04/03/18 14:48:32 GMT
FROM:    Gianpiero Tagliaferri at OAB-INAF  <taglia@merate.mi.astro.it>

A. Simoncelli, P. D'Avanzo, S. Campana, S. Covino, D. Fugazza,
A. Cucchiara, S. Kalogerakos, G. Tagliaferri, F.M. Zerbi (INAF-OAB);
G. Chincarini  (UNIMIB & INAF-OAB); G.L. Israel, L. Stella (INAF-OAR); 
D. Malesani (SISSA); A. De Luca (IASF, Milan) on behalf of a larger 
collaboration report: 

Following the improved position for the likely afterglow of GRB 
040223 (GCN 2525) provided by De Luca et al. (GCN 2547), we 
re-analysed our NTT + SofI data (JHKs filters, Tagliaferri et 
al. GCN 2535).

Inside the new error circle (99% confidence, 4.5'' radius) 
we found 13 objects: no one of these presents a typical afterglow 
behaviour (i.e. a monotonic decay).

For a list of these objects please refer to the table at the
following URL http://www.merate.mi.astro.it/~taglia/GRB040223/grb.html.
Objects within the error circle are identified with ID 1, 10, 12, 14, 
16, 19, 20, 21, 23, 24, 25, 30, 32.
Limiting Ks magnitude is found to be ~ 20 (referred to the 2MASS catalog).


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