Pulsar death line revisited -- II. 'The death valley'

Abstract

In this paper, which is the second in a series of papers, we analyse what parameters can determine the width of the radio pulsar 'death valley' in the $P$-${\dot P}$ diagram. Using exact expression for the maximum potential drop, which can be realised over magnetic polar caps and the corresponding threshold for the secondary plasma production determined in Paper I, we analyse in detail the observed distribution of pulsars taking into account all the possible parameters (radius $R$ and moment of inertia of a neutron star $I_{\rm r}$, high-energy tail in the $\gamma$-quanta energy distribution giving rise to secondary particles, etc.) which could broaden 'the death line'. We show that the consistent allowance for all these effects leads to a sufficiently wide of 'the death valley' containing all the observed pulsars even for dipole magnetic field of a neutron star.