The signature of the central engine in the weakest relativistic explosions: GRB 100316D
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
- CSIRO Astronomy and Space Science, Australia Telescope National Facility, P.O. Box 76, Epping, NSW 1710 (Australia)
- Astronomy Department, University of Virginia, Charlottesville, VA 22904 (United States)
- Department of Astronomy, University of Wisconsin-Madison, 2535 Sterling Hall, 475 N. Charter Street, Madison, WI 53706-1582 (United States)
- Racah Institute for Physics, Edmund J. Safra Campus, Hebrew University of Jerusalem, Jerusalem 91904 (Israel)
- Scuola Normale Superiore, 7, I-56126 Pisa (Italy)
We present late-time radio and X-ray observations of the nearby sub-energetic gamma-ray burst (GRB)100316D associated with supernova (SN) 2010bh. Our broad-band analysis constrains the explosion properties of GRB 100316D to be intermediate between highly relativistic, collimated GRBs and the spherical, ordinary hydrogen-stripped SNe. We find that ∼10{sup 49} erg is coupled to mildly relativistic (Γ = 1.5-2), quasi-spherical ejecta, expanding into a medium previously shaped by the progenitor mass-loss with a rate of M-dot ∼ 10{sup −5} M{sub ⊙} yr{sup −1} (for an assumed wind density profile and wind velocity v{sub w} = 1000 km s{sup –1}). The kinetic energy profile of the ejecta argues for the presence of a central engine and identifies GRB 100316D as one of the weakest central-engine-driven explosions detected to date. Emission from the central engine is responsible for an excess of soft X-ray radiation that dominates over the standard afterglow at late times (t > 10 days). We connect this phenomenology with the birth of the most rapidly rotating magnetars. Alternatively, accretion onto a newly formed black hole might explain the excess of radiation. However, significant departure from the standard fall-back scenario is required.
- OSTI ID:
- 22342046
- Journal Information:
- Astrophysical Journal, Vol. 778, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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