The location of the Crab pulsar emission region: restrictions on synchrotron emission models
2010 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 516, A65- p.Article in journal (Refereed) Published
Recent observations of the Crab pulsar show no evidence of a spectral break in the infrared regime. It is argued that the observations are consistent with a power-law spectrum in the whole observable infrared-optical range. This is taken as the starting point for evaluating of how self-consistent incoherent synchrotron models fare in a comparison with observations. Inclusion of synchrotron self-absorption proves important as does the restriction on the observed size of the emission region imposed by the relativistic beaming thought to define the pulse profile. It is shown that the observations can be used to derive two independent constraints on the distance from the neutron star to the emission region; in addition to a direct lower limit, an indirect measure is obtained from an upper limit to the magnetic field strength. Both of these limits indicate that the emission region is located at a distance considerably greater than the light cylinder radius. The implications of this result are discussed, and it is emphasized that, for standard incoherent synchrotron models to fit inside the light cylinder, rather special physical conditions need to be invoked.
Place, publisher, year, edition, pages
2010. Vol. 516, A65- p.
pulsars: individual: PSR B0531+21, radiation mechanisms: non-thermal, stars: neutron, pulsars: general
IdentifiersURN: urn:nbn:se:su:diva-49468DOI: 10.1051/0004-6361/201014049ISI: 000280275400080OAI: oai:DiVA.org:su-49468DiVA: diva2:377994
authorCount :32010-12-152010-12-142010-12-15Bibliographically approved