TY - JOUR
T1 - Short GRB 130603B
T2 - Discovery of a jet break in the optical and radio afterglows, and a mysterious late-time X-ray excess
AU - Fong, W.
AU - Berger, E.
AU - Metzger, B. D.
AU - Margutti, R.
AU - Chornock, R.
AU - Migliori, G.
AU - Foley, R. J.
AU - Zauderer, B. A.
AU - Lunnan, R.
AU - Laskar, T.
AU - Desch, S. J.
AU - Meech, K. J.
AU - Sonnett, S.
AU - Dickey, C.
AU - Hedlund, A.
AU - Harding, P.
PY - 2014/1/10
Y1 - 2014/1/10
N2 - We present radio, optical/NIR, and X-ray observations of the afterglow of the short-duration Swift and Konus-Wind GRB 130603B, and uncover a break in the radio and optical bands at ∼0.5 day after the burst, best explained as a jet break with an inferred jet opening angle of ∼4°-8°. GRB 130603B is only the third short GRB with a radio afterglow detection to date, and represents the first time that a jet break has been evident in the radio band. We model the temporal evolution of the spectral energy distribution to determine the burst explosion properties and find an isotropic-equivalent kinetic energy of ∼(0.6-1.7) × 1051 erg and a circumburst density of ∼5 × 10-3-30 cm-3. From the inferred opening angle of GRB 130603B, we calculate beaming-corrected energies of E γ ∼ (0.5-2) × 1049 erg and E K ∼ (0.1-1.6) × 1049 erg. Along with previous measurements and lower limits we find a median opening angle of ∼10°. Using the all-sky observed rate of 10 Gpc-3 yr-1, this implies a true short GRB rate of ∼20 yr-1 within 200 Mpc, the Advanced LIGO/VIRGO sensitivity range for neutron star binary mergers. Finally, we uncover evidence for significant excess emission in the X-ray afterglow of GRB 130603B at ≳ 1 day and conclude that the additional energy component could be due to fall-back accretion or spin-down energy from a magnetar formed following the merger.
AB - We present radio, optical/NIR, and X-ray observations of the afterglow of the short-duration Swift and Konus-Wind GRB 130603B, and uncover a break in the radio and optical bands at ∼0.5 day after the burst, best explained as a jet break with an inferred jet opening angle of ∼4°-8°. GRB 130603B is only the third short GRB with a radio afterglow detection to date, and represents the first time that a jet break has been evident in the radio band. We model the temporal evolution of the spectral energy distribution to determine the burst explosion properties and find an isotropic-equivalent kinetic energy of ∼(0.6-1.7) × 1051 erg and a circumburst density of ∼5 × 10-3-30 cm-3. From the inferred opening angle of GRB 130603B, we calculate beaming-corrected energies of E γ ∼ (0.5-2) × 1049 erg and E K ∼ (0.1-1.6) × 1049 erg. Along with previous measurements and lower limits we find a median opening angle of ∼10°. Using the all-sky observed rate of 10 Gpc-3 yr-1, this implies a true short GRB rate of ∼20 yr-1 within 200 Mpc, the Advanced LIGO/VIRGO sensitivity range for neutron star binary mergers. Finally, we uncover evidence for significant excess emission in the X-ray afterglow of GRB 130603B at ≳ 1 day and conclude that the additional energy component could be due to fall-back accretion or spin-down energy from a magnetar formed following the merger.
KW - gamma-ray burst: individual (130603B)
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U2 - 10.1088/0004-637X/780/2/118
DO - 10.1088/0004-637X/780/2/118
M3 - Article
AN - SCOPUS:84891315089
VL - 780
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 118
ER -