TITLE:   GCN CIRCULAR
NUMBER:  17871
SUBJECT: GRB 150513A: request for X-ray follow up
DATE:    15/05/25 23:53:47 GMT
FROM:    Remo Rufinni at ICRA  <ruffini@icra.it>

R. Ruffini, C. L. Bianco, M. Enderli, M. Kovacevic, M. Muccino, G. B.
Pisani, J. A. Rueda, Y. Wang reports:

The observation of high-energy emission from GRB 150513A by Fermi-LAT
[1] clearly points to a binary-driven hypernova (BdHN) nature of the
source [2], in spite of the missing follow-up from Swift/XRT and UVOT
due to a Sun observing constraint which will last until the 28th of May
[3].

BdHNe have a standard behavior in the late X-ray luminosity [4,5,6],
thus we expect the X-ray emission of GRB 150513A to follow such a
behavior as well.

Assuming that the X-ray luminosity of GRB 150513A is comparable with
the BdHN prototypical one of GRB 090618 (GRB 130427A), a detection by
Swift/XRT of GRB 150513A on the 28th of May implies an upper limit for
its redshift z<0.8 (z<2).

Therefore, we strongly encourage observation by Swift/XRT of GRB
150513A from the 28th of May on. This would give a fundamental
information on the nature of this source, despite the absence of data
between May 13th and May 28th.

References:
[1] Kocevski et al. 2015, GCN 17812
[2] Ruffini et al. 2015, ApJ, 798, 10R
[3] Kocevski et al. 2015, GCN 17810
[4] Ruffini et al. 2014, A&A, 565, L10
[5] Pisani et al. 2013, A&A, 552, L5
[6] Ruffini et al. 2014, A&A, 569, A39