[vsnet-grb-info 15920] GRB141221A: REM afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17208
SUBJECT: GRB141221A: REM afterglow
DATE:    14/12/21 15:01:52 GMT
FROM:    Stefano Covino at Brera Astronomical Observatory  <stefano.covino at brera.inaf.it>

S. Covino (INAF/OAB) on behalf of the REM team:

We observed the field of the GRB141221A (Sonbas et al., GCN 17206) simultaneously in the optical and near infrared with the 60-cm robotic telescope REM at La Silla Observatory (Chile). The observations started about 1 min after the GRB, when the field was at an airmass of about 2.5 and continued for about one hour till the local twilight.

A bright source at a position consistent with the UVOT candidate afterglow is detected in all filter (grizJHK). 
At about 1.5 min after the GRB the afterglow was H~13.1 and faded down to H~15.8 more than 30 min later, with a decay index alpha~0.8.