A search for near infrared counterparts of three pulsar wind nebulae

P A Curran,S Chaty,J A Zurita Heras,A Coleiro

doi:10.1051/0004-6361/201117321

Abstract

While pulsar wind nebulae (PWNe) and their associated isolated pulsars are commonly detected at X-ray energies, they are much rarer at near infrared (nIR) and optical wavelengths. Here we examine three PWN systems in the Galactic plane - IGR J14003-6326, HESS J1632-478 and IGR J18490-0000 - in a bid to identify optical/nIR emission associated with either the extended PWNe or their previously detected X-ray point sources. We obtain optical/nIR images of the three fields with the ESO - New Technology Telescope and apply standard photometric and astrometric calibrations. We find no evidence of any extended emission associated with the PWNe in any of the fields; neither do we find any new counterparts to the X-ray point sources, except to confirm the magnitude of the previously identified counterpart candidate of IGR J18490-0000. Further observations are required to confirm the association of the nIR source to IGR J18490-0000 and to detect counterparts to IGR J14003-6326 and HESS J1632-478, while a more accurate X-ray position is required to reduce the probability of a chance superposition in the field of the latter.

Highlights

Along with the typical supernova remnant (SNR), a rapidlyrotating, highly-magnetised neutron star, or pulsar, is frequently an end product of a supernova explosion
The pulsars themselves, as well as being detected as point sources in radio and X-ray where the pulsations are observed, may be detected at optical or near infrared wavelengths. At these wavelengths the emission will be that of an isolated, non-accreting neutron star which is intrinsically dim and very few (12 out of ∼1800) have been detected in this regime (Mignani 2011). We examine three such pulsar wind nebula (PWN) systems in the Galactic plane – IGR J14003−6326, HESS J1632−478 and IGR J18490−0000 – in a bid to identify extended optical/nIR (OIR) emission associated with the pulsar wind nebulae (PWNe) or optical/nIR
Neither do we find any nIR counterparts to the X-ray point sources, except to confirm the Ks magnitude of the previously identified counterpart of IGR J18490−0000 (Ratti et al 2010)

Summary

Introduction

Along with the typical supernova remnant (SNR), a rapidlyrotating, highly-magnetised neutron star, or pulsar, is frequently an end product of a supernova explosion. The pulsar has high levels of rotational energy which is dissipated via a highly relativistic particle wind The interaction of this wind with the surrounding medium, i.e., the ejecta of the supernova explosion itself, causes a continuously refreshed shock wave known as a pulsar wind nebula (PWN). These PWNe emit via synchrotron and inverse Compton processes and are observed across the spectrum from radio to optical to X-ray and higher energies At these wavelengths the emission will be that of an isolated, non-accreting neutron star which is intrinsically dim and very few (12 out of ∼1800) have been detected in this regime (Mignani 2011)

Results

Discussion

Conclusion