Acceleration by Pulsar Winds in Binary Systems
Abstract
In the absence of accretion torques, a pulsar in a binary system will spin down due to electromagnetic dipole radiation, and the spin-down power will drive a wind of relativistic electron-position pairs. Winds from pulsars with short periods will prevent any subsequent accretion but may be confined by the companion star atmosphere, wind, or magnetosphere to form a standing shock. This paper investigates the possibility of particle acceleration at such a pulsar wind shock and the production of VHE and UHE gamma-rays from interactions of accelerated protons in the companion star's wind or atmosphere. It is found that, in close binaries containing active pulsars, protons will be shock accelerated to a maximum energy dependent on the pulsar spin-down luminosity. If a significant fraction of the spin-down power goes into particle acceleration, these systems should be sources of VHE and possibly UHE gamma-rays. The application of the pulsar wind model to binary sources such as Cygnus X-3 is discussed, as well as the possibility of observing VHE gamma-rays from known binary radio pulsar systems.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 1990
- DOI:
- 10.1086/169009
- Bibcode:
- 1990ApJ...358..561H
- Keywords:
-
- Binary Stars;
- Electromagnetic Radiation;
- Electron-Positron Pairs;
- Pulsars;
- Relativistic Effects;
- Stellar Winds;
- Magnetic Dipoles;
- Particle Acceleration;
- Standing Waves;
- Astrophysics;
- GAMMA RAYS: GENERAL;
- PARTICLE ACCELERATION;
- PULSARS;
- RADIATION MECHANISMS;
- STARS: BINARIES;
- STARS: WINDS