An origin for short gamma-ray bursts unassociated with current star formation
Författare
Summary, in English
Two short (< 2 s) gamma-ray bursts (GRBs) have recently been localized(1-4) and fading afterglow counterparts detected(2-4). The combination of these two results left unclear the nature of the host galaxies of the bursts, because one was a star-forming dwarf, while the other was probably an elliptical galaxy. Here we report the X-ray localization of a short burst (GRB 050724) with unusual gamma-ray and X-ray properties. The X-ray afterglow lies off the centre of an elliptical galaxy at a redshift of z = 0.258 (ref. 5), coincident with the position determined by ground-based optical and radio observations(6-8). The low level of star formation typical for elliptical galaxies makes it unlikely that the burst originated in a supernova explosion. A supernova origin was also ruled out for GRB 050709 ( refs 3, 31), even though that burst took place in a galaxy with current star formation. The isotropic energy for the short bursts is 2 - 3 orders of magnitude lower than that for the long bursts. Our results therefore suggest that an alternative source of bursts - the coalescence of binary systems of neutron stars or a neutron star-black hole pair - are the progenitors of short bursts.
Avdelning/ar
Publiceringsår
2005
Språk
Engelska
Sidor
994-996
Publikation/Tidskrift/Serie
Nature
Volym
438
Dokumenttyp
Artikel i tidskrift
Förlag
Nature Publishing Group
Ämne
- Astronomy, Astrophysics and Cosmology
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 0028-0836