Publication | Closed Access
Formation of very strongly magnetized neutron stars - Implications for gamma-ray bursts
2.5K
Citations
0
References
1992
Year
Neutron stars with dipole fields of 10^14–10^15 G, known as magnetars, can form via efficient helical dynamo action during the first seconds after collapse, spin down rapidly, and may acquire large recoil velocities through anisotropic neutrino emission, core instabilities, or magnetic winds, making them hard to detect. The authors propose that gamma‑ray bursts powered by the vast magnetic reservoirs of magnetars constitute their primary observable signature. A convective dynamo can generate a strong dipole field in a neutron‑star merger remnant only if the merged star survives for roughly 10–100 ms. Large recoil velocities would unbind most magnetars from the Galaxy, and soft gamma repeaters appear to be young magnetars. Published in The Astrophysical Journal (June 1992, DOI 10.1086/186413).
view Abstract Citations (2209) References (42) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Formation of Very Strongly Magnetized Neutron Stars: Implications for Gamma-Ray Bursts Duncan, Robert C. ; Thompson, Christopher Abstract Neutron stars with unusually strong magnetic dipole fields B_dipole ~ 10^14 - 10^15 G, can form when conditions for efficient helical dynamo action are met during the first few seconds after gravitational collapse. Such high-field neutron stars, "magnetars," initially rotate with short periods ~ 1 ms, but quickly lose most of their rotational energy via magnetic braking, giving a large energy boost to the associated supernova explosion. Several mechanisms unique to magnetars can plausibly generate large (~ 1000 km/s) recoil velocities. These include anisotropic neutrino emission, core rotational instability and fragmentation, and/or anisotropic magnetic winds. Magnetars are relatively difficult to detect because they drop below the radio death line faster than ordinary pulsars, and because they probably do not remain bound in binary systems. We conjecture that their main observational signature is gamma-ray bursts powered by their vast reservoirs of magnetic energy. If they acquire large recoils, most magnetars are unbound from the Galaxy or reside in an extended, weakly bound Galactic corona. There is evidence that the soft gamma repeaters are young magnetars. Finally, we note that a convective dynamo can also generate a very strong dipole field after the merger of a neutron star binary, but only if the merged star survives for as long as ~ 10-100 ms. Publication: The Astrophysical Journal Pub Date: June 1992 DOI: 10.1086/186413 Bibcode: 1992ApJ...392L...9D Keywords: Dynamo Theory; Gamma Ray Bursts; Neutron Stars; Star Formation; Stellar Magnetic Fields; Gravitational Collapse; Stellar Rotation; Supernovae; Astrophysics; GAMMA RAYS: BURSTS; MAGNETIC FIELDS; STARS: NEUTRON; STARS: PULSARS: GENERAL full text sources ADS | data products SIMBAD (3)