O. Fox

Publications (4)41.81 Total impact

• Source

  Available from: Vandiver Chaplin

  Article: A relativistic type Ibc supernova without a detected gamma-ray burst.

  A M Soderberg, S Chakraborti, G Pignata, R A Chevalier, P Chandra, A Ray, M H Wieringa, A Copete, V Chaplin, V Connaughton, [......], M Hamuy, C Fransson, O Fox, E M Levesque, J E Grindlay, P Challis, R J Foley, R P Kirshner, P A Milne, M A P Torres
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  ABSTRACT: Long duration gamma-ray bursts (GRBs) mark the explosive death of some massive stars and are a rare sub-class of type Ibc supernovae. They are distinguished by the production of an energetic and collimated relativistic outflow powered by a central engine (an accreting black hole or neutron star). Observationally, this outflow is manifested in the pulse of gamma-rays and a long-lived radio afterglow. Until now, central-engine-driven supernovae have been discovered exclusively through their gamma-ray emission, yet it is expected that a larger population goes undetected because of limited satellite sensitivity or beaming of the collimated emission away from our line of sight. In this framework, the recovery of undetected GRBs may be possible through radio searches for type Ibc supernovae with relativistic outflows. Here we report the discovery of luminous radio emission from the seemingly ordinary type Ibc SN 2009bb, which requires a substantial relativistic outflow powered by a central engine. A comparison with our radio survey of type Ibc supernovae reveals that the fraction harbouring central engines is low, about one per cent, measured independently from, but consistent with, the inferred rate of nearby GRBs. Independently, a second mildly relativistic supernova has been reported.
  Nature 01/2010; 463(7280):513-5. · 36.28 Impact Factor
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  Available from: Vandiver Chaplin

  Article: The High-metallicity Explosion Environment of the Relativistic Supernova 2009bb

  E. M. Levesque, A. M. Soderberg, R. J. Foley, E. Berger, L. J. Kewley, S. Chakraborti, A. Ray, M. A. P. Torres, P. Challis, R. P. Kirshner, [......], V. Connaughton, A. Copete, O. Fox, C. Fransson, J. E. Grindlay, M. A. Hamuy, P. A. Milne, G. Pignata, M. D. Stritzinger, and M. H. Wieringa
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  ABSTRACT: We investigate the environment of the nearby (d 40 Mpc) broad-lined Type Ic supernova (SN) 2009bb. This event was observed to produce a relativistic outflow likely powered by a central accreting compact object. While such a phenomenon was previously observed only in long-duration gamma-ray bursts (LGRBs), no LGRB was detected in association with SN 2009bb. Using an optical spectrum of the SN 2009bb explosion site, we determine a variety of interstellar medium properties for the host environment, including metallicity, young stellar population age, and star formation rate. We compare the SN explosion site properties to observations of LGRB and broad-lined SN Ic host environments on optical emission line ratio diagnostic diagrams. Based on these analyses, we find that the SN 2009bb explosion site has a metallicity between 1.7 Z ☉ and 3.5 Z ☉, in agreement with other broad-lined SN Ic host environments and at odds with the low-redshift LGRB host environments and recently proposed maximum metallicity limits for relativistic explosions. We consider the implications of these findings and the impact that SN 2009bb's unusual explosive properties and environment have on our understanding of the key physical ingredient that enables some SNe to produce a relativistic outflow.
  The Astrophysical Journal Letters 12/2009; 709(1):L26. · 5.53 Impact Factor
• Article: A relativistic type Ibc supernova without a detected γ-ray burst

  A. M. Soderberg, S. Chakraborti, G. Pignata, R. A. Chevalier, P Chandra, A Ray, M. H. Wieringa, A. Copete, V. Chaplin, V. Connaughton, [......], M. Hamuy, C. Fransson, O. Fox, E. M. Levesque, J. E. Grindlay, P. Challis, R. J. Foley, R. P. Kirshner, P. A. Milne, M. A. P. Torres
• Article: THE HIGH-METALLICITY EXPLOSION ENVIRONMENT OF THE RELATIVISTIC SUPERNOVA 2009BB1

  Emily M. Levesque, M. Soderberg, R. J. Foley, E. Berger, L. J. Kewley, S. Chakraborti, A Ray, M. A. P. Torres, P. Challis, R. P. Kirshner, [......], V. Connaughton, A. Copete, O. Fox, C. Fransson, J. E. Grindlay, M. A. Hamuy, P. A. Milne, G. Pignata, M. D. Stritzinger, M. H. Wieringa
  [show abstract] [hide abstract]
  ABSTRACT: We investigate the environment of the nearby (d 40 Mpc) broad-lined Type Ic supernova SN 2009bb. This event was observed to produce a relativistic outflow likely powered by a central ac- creting compact object. While such a phenomenon was previously observed only in long-duration gamma-ray bursts (LGRBs), no LGRB was detected in association with SN 2009bb. Using an optical spectrum of the SN 2009bb explosion site, we determine a variety of ISM properties for the host en- vironment, including metallicity, young stellar population age, and star formation rate. We compare the SN explosion site properties to observations of LGRB and broad-lined SN Ic host environments on optical emission line ratio diagnostic diagrams. Based on these analyses, we find that the SN 2009bb explosion site has a metallicity between 1.7Z and 3.5Z , in agreement with other broad-lined SN Ic host environments and at odds with the low-redshift LGRB host environments and recently pro- posed maximum metallicity limits for relativistic explosions. We consider the implications of these findings and the impact that SN 2009bb’s unusual explosive properties and environment have on our understanding of the key physical ingredient that enables some SNe to produce a relativistic outflow.