[AAVSO-HEN] GRB 090201: VLT NIR observations

[grb at aavso.org]

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TITLE:   GCN CIRCULAR
NUMBER:  8871
SUBJECT: GRB 090201: VLT NIR observations
DATE:    09/02/02 04:51:55 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo at brera.inaf.it>

P. D'Avanzo, C. C. Thoene, D. Fugazza (INAF-OAB), V. D'Elia, S. 
Piranomonte (INAF-OAR), R. Salvaterra, S. Covino, S. Campana (INAF-OAB), 
G. Chincarini (Univ. Bicocca) report, on behalf of the MISTICI 
collaboration:

We continued observing the field of GRB 090201 (Oates et a., GCN 8865) 
with the ESO-VLT in imaging mode with the ISAAC NIR camera. Observations 
were carried out in J, H and K-band about 9.5 hours after the burst.

The optical afterglow candidate (D'Avanzo et al. GCN 8869) is not 
visible in the coadded images down to the following upper limits (3sigma 
c.l.): J = 23.0, H = 22.4, K = 21.1 (calibrated against the 2MASS 
catalogue).

The absence of a NIR detection suggests that the object observed by 
D'Avanzo et al. (GCN 8869) is not the optical afterglow of GRB 090201 
but probably a field galaxy. Further analysis is in progress.

We acknowledge the VLT staff for their support, in particular E. Valenti 
and J. Smoker.