PSR J1856+0245: Arecibo Discovery of a Young, Energetic Pulsar Coincident with the TeV Gamma-ray Source HESS J1857+026

TL;DR

This paper reports the discovery of a young, energetic pulsar, PSR J1856+0245, coincident with a TeV gamma-ray source, suggesting it powers a pulsar wind nebula responsible for the observed high-energy emission.

Contribution

The discovery of PSR J1856+0245 and its association with HESS J1857+026 is new, providing insights into pulsar wind nebulae linked to very-high-energy gamma-ray sources.

Findings

PSR J1856+0245 has a spin period of 81 ms and a characteristic age of 21 kyr.

The pulsar's gamma-ray efficiency is approximately 3.1%.

Faint X-ray emission supports the pulsar wind nebula hypothesis.

Abstract

We present the discovery of the Vela-like radio pulsar J1856+0245 in the Arecibo PALFA survey. PSR J1856+0245 has a spin period of 81ms, a characteristic age of 21kyr, and a spin-down luminosity Edot = 4.6 x 10^36 ergs/s. It is positionally coincident with the TeV gamma-ray source HESS J1857+026, which has no other known counterparts. Young, energetic pulsars create wind nebulae, and more than a dozen pulsar wind nebulae have been associated with very-high-energy (100GeV-100TeV) gamma-ray sources discovered with the HESS telescope. The gamma-ray emission seen from HESS J1857+026 is potentially produced by a pulsar wind nebula powered by PSR J1856+0245; faint X-ray emission detected by ASCA at the pulsar's position supports this hypothesis. The inferred gamma-ray efficiency is epsilon_gamma = L_gamma/Edot = 3.1% (1-10TeV, for a distance of 9kpc), comparable to that observed in similar associations.