2011ApJ...736..127W -
Astrophys. J., 736, 127 (2011/August-1)
Death line of gamma-ray pulsars with outer gaps.
WANG R.-B. and HIROTANI K.
Abstract (from CDS):
We analytically investigate the condition for a particle accelerator to be active in the outer magnetosphere of a rotation-powered pulsar. Within the accelerator (or the gap), the magnetic-field-aligned electric field accelerates electrons and positrons, which emit copious gamma-rays via the curvature process. If one of the gamma-rays emitted by a single pair materializes as a new pair on average, the gap is self-sustained. However, if the neutron-star spin-down rate decreases below a certain limit, the gap becomes no longer self-sustained and the gamma-ray emission ceases. We explicitly compute the multiplicity of cascading pairs and find that the obtained limit corresponds to a modification of the previously derived outer-gap death line. In addition to this traditional death line, we find another death line, which becomes important for millisecond pulsars, by separately considering the threshold of photon-photon pair production. Combining these traditional and new death lines, we give predictions on the detectability of gamma-ray pulsars with Fermi and AGILE. An implication for X-ray observations of heated polar-cap emission is also discussed.
Abstract Copyright:
∼
Journal keyword(s):
gamma rays: stars - magnetic fields - methods: analytical - stars: neutron
Simbad objects:
18
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2011ApJ...736..127W and select 'bookmark this link' or equivalent in the popup menu