The environments around long-duration gamma-ray burst progenitors

Christopher L. Fryer, Gabriel Rockefeller, Patrick Young

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Gamma-ray burst (GRB) afterglow observations have allowed us to significantly constrain the engines producing these energetic explosions. The redshift and position information provided by these afterglows have already allowed us to limit the progenitors of GRBs to only a few models. The afterglows may also provide another observation that can place further constraints on the GRB progenitor: measurements telling us about the environments surrounding GRBs. Current analyses of GRB afterglows suggest that roughly half of long-duration gamma-ray bursts occur in surroundings with density profiles that are uniform. We study the constraints placed by this observation on both the classic "collapsar" massive star progenitor and its relative, the "helium-merger" progenitor. We study several aspects of wind mass loss and find that our modifications to the standard Wolf-Rayet mass-loss paradigm are not sufficient to produce constant density profiles. Although this does not rule out the standard "collapsar" progenitor, it does suggest a deficiency with this model. We then focus on the He-merger models and find that such progenitors can fit this particular constraint well. We show how detailed observations could not only determine the correct progenitor for GRBs but also allow us to study binary evolution physics.

Original languageEnglish (US)
Pages (from-to)1269-1285
Number of pages17
JournalAstrophysical Journal
Issue number2 I
StatePublished - Aug 20 2006


  • Binaries: close
  • Black hole physics
  • Gamma rays: bursts
  • Stars: neutron

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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