GCN Circular 3423
Subject
GRB 050509B and short GRB-SN association?
Event
Date
2005-05-15T08:56:20Z (21 years ago)
From
Arnon Dar at Technion-Israel Inst. of Tech <arnon@physics.technion.ac.il>
S. Dado (Technion) and A. Dar (Technion) report:
The leading scenarios for the production of short-duration GRBs involve
(a) neutron-star mergers [1] (b) super flares from SGRs (GCN 2942 and [2])
(c) gravitational collapse of neutron-stars to strange-quark stars [3] (d)
gravitational collapse of C/O white dwarfs to neutron stars (GCN 2174) and
[3]). While scenarios (a),(b) are not associated with standard optical
SNe, scenarios (c),(d) are expected to produce a standard optical SN.
In particular, in scenario (d), a bright SNIa is expected at the GRB
location with a standard rest frame optical light curves which peak around
20 days after burst with un-reddened absolute rest frame magnitudes,
Bmax~-19.47, Vmax~-19.42, Rmax~-19.42 and Imax~-19.06 (+\-0.15 magnitude).
GRB050509B (GCN 3381) is the first well localized short-duration (~30 ms)
GRB. It allows a late time search of an SN associated with a short
duration GRB. In the observer frame the expected un-reddened spectral
energy density at a frequency nu and a time t after burst is:
F(nu,t)=((1+z) [D_L(z')]^2 / (1+z')[D_L(z)]^2) Ftsn(nu',t')
where z' is the redshift of the template SNIa whose spectral energy
density is Ftsn and nu'=[(1+z)/(1+z')] nu, t'=[(1+z')/(1+z)] t.
If GRB050509B was produced in an SNIa in the galaxy cluster NSC
J123610+285901 at a redshift z~0.225 (GCN 3390), its observed V-band light
curve should peak near t=25 days after burst with Vmax~20.43+/- 0.15
(extinction in the host galaxy is not included, but Galactic extinction in
the direction of GRB 050509B, Av~0.06 [5] is included).
Despite the failures so far to detect an optical afterglow
within/near the refined XRT error circle (GCN 3395) of GRB 050509B, an SN
search within/near the burst XRT error circle, with the most powerful
telescopes such as Keck, VLT, Subaru and HST, is highly encouraged.
[1] Goodman, J, Dar, A, & Nussinov, S. 1987, ApJ, 314, L7
[2] Hurley, K., et al. 2005, astro-ph/0502329
[2] Dar, A. 1999, A&AS, 138, 505
[3] Dar, A. & De Rujula, A. 2004, Physics Reports, 405, 203
[4] Germany, L. M., et al. 2004, A&A 415, 863
[5] Schlegel, D. J.; Finkbeiner, D. P. & Davis, M. 1998, ApJ, 500, 525