[vsnet-grb-info 17714] GRB 160303A: Continued optical monitoring from NOT

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19152
SUBJECT: GRB 160303A: Continued optical monitoring from NOT
DATE:    16/03/05 20:35:02 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte at iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), T. Kruehler (MPE Garching)
D. Xu (NAOC/CAS), D. Malesani (DARK/NBI), Z. Cano (U. Iceland),
N.R. Tanvir (U. Leicester),M. Messa (Stockholm Univ., Oskar Klein Centre), 
E. Gafton (NOT, Stockholm Univ. and Oskar Klein Centre) and I. R. Losada 
(Nordita and Stockholm Univ.) report on behalf of a larger collaboration:

We continued the monitoring of GRB 160303A (Beardmore et al., 
GCN 19126) with MOSCA at the 2.5m Nordic Optical Telescope 
(La Palma, Spain).

On a 9x300s  observation with mean epoch 2:10 UT of 5 March 2016 
(37.27 hr after the burst) we detect the afterglow (Butler et al GCN19131) 
at a magnitude of r = 25.2 +/- 0.2, as compared to the SDSS field stars. 
This is consistent with the magnitude reported by GROND (Bolmer et al. 
GCN 19150) at a similar epoch.

Gathering the r-band data from the different GCNs (Butler et al. GCN19131; 
de Ugarte Postigo et al. GCN 19136; Jeong et al. GCN 19140; Im et al. 
GCN 19141; Klose et al. GCN 19142; de Ugarte Postigo et al. GCN 19143; 
Graham et al. GCN 19144; Bolmer et al. GCN 19150) the light curve seems 
to have been flat, or even increasing in brightness during the first 4-8 hrs 
after the burst. After this, the light curve begins a steep decay with 
alpha = 1.23 +/- 0.14 (F_nu ~ t^-alpha). This is not unlike the behaviour of 
other short GRBs, f.ex. GRB 130603B (de Ugarte Postigo et al. 2014 
A&A 563, 62), which was interpreted as being a magnetar powered event.