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

J. W. T. Hessels , D. J. Nice , B. M. Gaensler , V. M. Kaspi , D. R. Lorimer , D. J. Champion , A. G. Lyne , M. Kramer , J. M. Cordes , P. C. C. Freire , F. Camilo , S. M. Ransom , J. S. Deneva , N. D. R. Bhat , Ismaël Cognard (1) , F. Crawford , F. A. Jenet , L. Kasian , P. Lazarus , J. van Leeuwen , M. A. Mclaughlin , I. H. Stairs , B. W. Stappers , A. Venkataraman

1 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace

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 81 ms, a characteristic age of 21 kyr, and a spin-down luminosity Ė = 4.6 × 10³⁶ ergs s^-1. It is positionally coincident with the TeV γ-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 (100 GeV-100 TeV) γ-ray sources discovered with the HESS telescope. The γ-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 γ-ray efficiency is epsilon_γ = L_γ/Ė =3.1 % (1-10 TeV, for a distance of 9 kpc), comparable to that observed in similar associations.

Keywords: gamma rays: observations; pulsars: general; pulsars: individual: PSR J1856&plus0245; stars: neutron; X-rays: individual: AX J185651&plus0245; Astrophysics

Domains: Sciences of the Universe [physics]

J. W. T. Hessels, D. J. Nice, B. M. Gaensler, V. M. Kaspi, D. R. Lorimer, et al.. PSR J1856+0245: Arecibo Discovery of a Young, Energetic Pulsar Coincident with the TeV γ-Ray Source HESS J1857+026. The Astrophysical journal letters, 2008, 682, pp.L41. ⟨10.1086/590908⟩. ⟨insu-03611281⟩