Letter to the Editor

Discovery of X-ray emission from the young radio pulsar PSR J1357–6429

¹ Università degli Studi di Pavia, Dipartimento di Fisica Nucleare e Teorica and INFN-Pavia, via Bassi 6, 27100 Pavia, Italy e-mail: paoloesp@iasf-milano.inaf.it
² INAF - Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via Bassini 15, 20133 Milano, Italy
³ Università degli Studi di Milano - Bicocca, Dipartimento di Fisica G. Occhialini, p.za della Scienza 3, 20126 Milano, Italy

Received: 14 March 2007
Accepted: 10 April 2007

Abstract

We present the first X-ray detection of the very young pulsar PSR J1357-6429 (characteristic age of 7.3 kyr) using data from the XMM-Newton and Chandra satellites. We find that the spectrum is well described by a power-law plus blackbody model, with photon index and blackbody temperature  eV. For the estimated distance of 2.5 kpc, this corresponds to a 2–10 keV luminosity of ~1.2  10³² erg s^-1, thus the fraction of the spin-down energy channeled by PSR J1357-6429 into X-ray emission is one of the lowest observed. The Chandra data confirm the positional coincidence with the radio pulsar and allow to set an upper limit of 3  10³¹ erg s^-1 on the 2–10 keV luminosity of a compact pulsar wind nebula. We do not detect any pulsed emission from the source and determine an upper limit of 30% for the modulation amplitude of the X-ray emission at the radio frequency of the pulsar.