Which unidentified EGRET sources are gamma-ray pulsars?

Abstract

We consider high energy γ-ray radiation from the radio pulsars associated with some unidentified EGRET γ-ray sources. Calculated efficiencies for the conversion of spin-down power to γ-rays and the energy spectra of the high energy γ-rays from these possible γ-ray pulsars in outer gap models are compared with observed results. Of these possible γ-ray pulsars, our results indicate that (i) PSR B1900+05 is not a possible γ-ray pulsar; (ii) although the newly discovered young radio pulsar PSR J1105-6107 is a possible γ-ray pulsar, it may not account for the observed high energy γ-ray emission from 2EG J1103-6106; (iii) the high energy γ-rays from 2EG J1801-2312 and 2EG J1857+0118 may not be produced completely by radio pulsars PSR B1758-23 and PSR B1853+01 respectively; (iv) the counterparts (radio pulsars PSR B1046-58 and PSR B1823-13) of 2EG J1049-5247 and 2EG J1825-1307 are possible γ-ray pulsars; and (v) 2EG J0008-7307 associated with a young supernova remnant CTA 1 may contain a γ-ray pulsar with period 0.16 ≥ P ≥ 0.12 s.