posted on 2006-11-03, 12:42authored byAndrew J. Levan, Graham A. Wynn, Robert Chapman, Melvyn B. Davies, Andrew R. King, Robert S. Priddey, Nial R. Tanvir
Recent progress on the nature of short-duration gamma-ray bursts has shown that a fraction of them originate in the local Universe. These systems may well be the result of giant flares from soft gamma-repeaters (highly magnetized neutron stars commonly known as magnetars). However, if these neutron stars are formed via the core collapse of massive stars then itwould be
expected that the bursts should originate from predominantly young stellar populations, while correlating the positions of BATSE short bursts with structure in the local Universe reveals a
correlation with all galaxy types, including those with little or no ongoing star formation. This is a natural outcome if, in addition to magnetars formed via the core collapse of massive stars, they also form via accretion-induced collapse following the merger of two white dwarfs, one of which is magnetic.We investigate this possibility and find that the rate of magnetar production via white dwarf–white dwarf (WD–WD) mergers in the Milky Way is comparable to the rate of production via core collapse. However, while the rate of production of magnetars by core collapse is proportional to the star formation rate, the rate of production via WD–WD mergers
(which have long lifetimes) is proportional to the stellar mass density, which is concentrated in early-type systems. Therefore magnetars produced via WD–WD mergers may produce soft gamma-repeater giant flares which can be identified with early-type galaxies. We also comment
on the possibility that this mechanism could produce a fraction of the observed short-duration burst population at higher redshift.
History
Citation
Monthly Notices of the Royal Astronomical Society Letters, 2006, 368, pp. L1-L5
Published in
Monthly Notices of the Royal Astronomical Society Letters
Publisher
Blackwell
issn
1745-3933
Available date
2006-11-03
Notes
Also available at http://www.blackwell-synergy.com/doi/abs/10.1111/j.1745-3933.2006.00144.x. The definitive version is available at www.blackwell-synergy.com