X‐Ray Spectra of Young Pulsars and Their Wind Nebulae: Dependence on Spin‐Down Energy Loss Rate
2003; IOP Publishing; Volume: 591; Issue: 1 Linguagem: Inglês
10.1086/375124
ISSN1538-4357
Autores Tópico(s)Astrophysics and Cosmic Phenomena
ResumoAn observational model is presented for the spectra of young rotation-powered pulsars and their 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 these pulsars and that of their associated pulsar wind nebulae, both of which are observed to be a function of the spin-down energy loss rate, . The 2-10 keV spectra of these objects are well characterized by an absorbed power-law model with photon indices, Γ, in the range of 0.6 < ΓPSR < 2.1 and 1.3 < ΓPWN < 2.3, for the pulsars and their nebulae, respectively. A linear regression fit relating these two sets of indexes yields ΓPWN = 0.91 ± 0.18 + (0.66 ± 0.11)ΓPSR, with a correlation coefficient of r = 0.97. The spectra of these pulsars are found to steepen as Γ = Γmax + α-1/2, with Γmax providing an observational limit on the spectral slopes of young rotation-powered 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.
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