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[51.01] Dependence of X-ray Spectra on Spin-down Energy for Young Pulsars and Their Structured Nebulae

E.V. Gotthelf (Columbia Astrophysics Lab)

An observational model is presented for the spectra of young pulsars and their structured nebulae based on a study of nine bright Crab-like pulsar systems observed with the Chandra X-ray observatory. A significant correlation is discovered between the X-ray spectra of young pulsars (PSRs) and that of their associated structured pulsar nebulae (SPNe), both of which are observed to depend on spin-down energy, \dot E. The 2-10 keV spectra of the pulsars and of their nebulae are both well characterized by an absorbed power-law model with photon index, \Gamma. A linear regression fit to the two sets of indexes reveal that \Gamma_SPN is proportional to \Gamma_PSR with a correlation coefficient of r=0.96. The spectral steepening goes as \Gamma = \Gamma_max + \alpha \dot E^-1/2, with \Gamma_max providing an observational limit on the observed spectra. We also find a systematic spectral steepening of the younger, more energetic, pulsars. These results reveal basic properties of young pulsar systems, allow new observational constraints on models of pulsar wind emission, and provide a means of predicting the energetics of pulsars lacking detected pulsations.

This work is supported by LTSA Grant NAG 5-7935 and ADP Grant NAG 5-9136.

The author(s) of this abstract have provided an email address for comments about the abstract: eric@astro.columbia.edu

Bulletin of the American Astronomical Society, 35#2
© 2003. The American Astronomical Soceity.