Inverse Mapping of Polarised Optical Emission from Pulsars : Basic Formulation and Determination of Emission Altitude

Abstract

We present an inverse mapping approach to determining the emission height of the optical photons from pulsars, which is directly constrained by empirical data. The model discussed is for the case of the Crab pulsar. Our method, using the optical Stokes parameters, determines the most likely geometry for emission including magnetic field inclination angle ($\alpha$), observers line of sight angle ($\chi$) and emission height. We discuss the computational implementation of the approach, along with any physical assumptions made. We find that the most likely emission altitude is at 20% of the light cylinder radius above the stellar surface, in the open field region. We also present a general treatment of the expected polarisation from synchrotron source with a truncated power law spectrum of particles.

17 pages 16 figures; accepted for publication in MNRAS

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Cited by in corpus (6)

• Optical Polarimetry of the Inner Crab Nebula and Pulsar
• The Galway Astronomical Stokes Polarimeter: An All-Stokes Optical Polarimeter with Ultra-High Time Resolution
• HST optical polarimetry of the Vela pulsar & nebula
• The INTEGRAL view of the pulsating hard X-ray sky: from accreting and transitional millisecond pulsars to rotation-powered pulsars and magnetars
• Circular polarisation of synchrotron radiation in high magnetic fields
• VLT polarimetry observations of PSR B0656+14