Constraint of Pulsar Wind Properties from Induced Compton Scattering off Radio Pulses

Mar 28, 2014, 2:30 PM
15m

Speaker

Dr Shuta Tanaka (Institute for Cosmic Ray Research, The University of Tokyo)

Description

Pulsar winds have problems in energy conversion and pair-cascade processes which determine the magnetization, the pair multiplicity and the bulk Lorentz factor of the wind. We study induced Compton scattering by a relativistically moving cold plasma to constrain wind properties by imposing that radio pulses from the pulsar itself are not scattered by the wind as was first studied by Wilson & Rees. We find that relativistic effects cause a significant increase or decrease of the scattering coefficient depending on scattering geometry. Applying the Crab pulsar wind, we obtain the lower limit of the bulk Lorentz factor of ~ 10 at the light cylinder when the wind velocity is significantly inclined with respect to the radio pulses. Considering the lower limit of the pair multiplicity 10^6.6 suggested by recent studies of the Crab Nebula, the large inclination angle of the wind velocity (order unity), the small size of radio pulse emission region (~ 10^3 cm) and the small magnetization parameter (order unity) are required for the pair multiplicity > 10^6.6.

Primary author

Dr Shuta Tanaka (Institute for Cosmic Ray Research, The University of Tokyo)

Co-author

Prof. Fumio Takahara (Osaka University)

Presentation materials