TITLE:   GCN CIRCULAR
NUMBER:  14913
SUBJECT: GRB 130603B: Analogy with GRB 090510A and possible connection with a supernova
DATE:    13/06/17 18:22:05 GMT
FROM:    Remo Rufinni at ICRA  <ruffini@icra.it>

R. Ruffini, C.L. Bianco, M. Enderli, M. Muccino, A.V. Penacchioni, G.B.
Pisani, J.A. Rueda, N. Sahakyan, Y. Wang report:

After a rest-frame time of 5000 sec from the BAT trigger (Melandri et
al., GCN 14735), the late X-ray rest-frame luminosity of GRB 130603B
overlaps the one of GRB 090510A (see the figure at:
<http://www.icra.it/temp/GCN/20130614.png>). This match occurs
irrespectively of their isotropic energies, which differ by a factor of
~50 (GRB 130603B: E_iso = 2.1 * 10^51 erg, Frederiks et al., GCN 14772;
GRB 090510A: E_iso = 1.1 * 10^53 erg, Muccino et al. 2013, ApJ, in
press, arXiv:1306.3467).

According to Muccino et al. 2013, GRB 090510A is a long GRB exploded in
a high density enviroment (10^3 particles/cm^3). The similarity shown
in the plot indicates that also GRB 130603B could be a long duration
GRB observed at closer distance (z~0.35). Therefore the detection (or
not detection) of a supernova associated to GRB 130603B between
20th-23rd of June, becomes a crucial test.

Observations are strongly encouraged.