[AAVSO-HEN] GRB 090102: optical decay

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN CIRCULAR
NUMBER:  8780
SUBJECT: GRB 090102: optical decay
DATE:    09/01/05 12:15:18 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani at astro.ku.dk>

D. Malesani, J. P. U. Fynbo (DARK/NBI), A. de Ugarte Postigo (ESO), J. 
Gorosabel (IAA/CSIC), S. Barros, E. Simpson (QUB), report on behalf of a 
larger collaboration:

We observed the afterglow of GRB 090102 (Mangano et al., GCN 8762; Klotz 
et al., GCN 8762) with the Nordic Optical Telescope equipped with 
ALFOSC, at several epochs. The decay in the R band is consistent with a 
single power law with slope alpha ~ 0.9 between 0.1 and 3 days after the 
GRB. This is in agreement with the early-time slopes reported by Afonso 
et al. (GCN 8771) and Cenko et al. (GCN 8773). There is marginal 
indication that the light curve may flatten at late times, which could 
be due to the presence of a host galaxy. Further observations are 
encouraged.

A plot with the light curve, including data from GROND (GCN 8771), P60 
(GCN 8773), and IAC80 (de Ugarte Postigo et al., GCN 8772) is posted at 
the following URL:

http://www.astro.ku.dk/~malesani/GRB/090102/lc.png