GCN Circular 18296
Subject
GRB 150906B: theoretical estimation of redshift and isotropic energy
Event
Date
2015-09-12T19:09:18Z (11 years ago)
From
Remo Rufinni at ICRA <ruffini@icra.it>
R. Ruffini, C.L. Bianco, M. Enderli, M. Kovacevic, L. Li, M. Muccino, R. Moradi, G.B. Pisani, J.A. Rueda, Y. Wang report:
In the GCN 18263 (Levan et al. 2015), the galaxy NGC 3313 (z=0.0124, d=54 Mpc), which lies within the detection horizon of Advanced-LIGO/VIRGO, is presumed to be the host galaxy of GRB 150906B. Consequently, the isotropic energy of GRB 150906B is inferred Eiso~10^{49} erg. In the GCN 18259 (Golenetskii et al., 2015) from Konus-Wind, the time-averaged spectrum of GRB 150906B fitted by a cutoff power law gives the peak energy Ep = 928(-95,+111) keV in the observer's frame.
From previous GRB statistics (see attached figure [1] and ref. [2]), a typical short GRB with Ep~1 MeV corresponds to Eiso~10^{51} erg. With a fluence of 2.8(-0.2,+0.2)x10^{-5} erg/cm2 from GCN 18259, the redshift of GRB 150906B is expected to be z > 0.06 (266 Mpc), most probably z~0.12 (555 Mpc). Therefore the host galaxy of GRB 150906B could be one of the others nearby.
This type of short GRBs with Eiso < 10^{52} erg originate from merging neutron stars (NSs) leading to a massive NS and not to a black hole [3]. In view of the small value of the energetic, we indicate these sources as short gamma-ray flash (SGRF). As opposed to the more energetic short gamma-ray bursts, the SGRFs never have GeV emission.
[1] The MuRuWaZha Ep-Eiso relation: <http://www.icranet.org/documents/MuRuWaZha.pdf>
[2] Zhang, F.-W., Shao, L., Yan, J.-Z., et al. 2012, ApJ 750, 88
[3] Ruffini, R., Muccino, M., Kovacevic., et al. 2015 ApJ 808, 190