Chandra X-ray Observations of PSR J1849-0001, its Pulsar Wind Nebula, and the TeV Source HESS J1849-000

Abstract

We obtained a 108-ks Chandra X-ray Observatory (CXO) observation of PSR J1849-0001 and its PWN coincident with the TeV source HESS J1849-000. By analyzing the new and old (archival) CXO data we resolved the pulsar from the PWN, explored the PWN morphology on arcsecond and arcminute scales, and measured the spectra of different regions of the PWN. Both the pulsar and the compact inner PWN spectra are hard with power-law photon indices of 1.20±0.07 and 1.36±0.14, respectively. The jet-dominated PWN with a relatively low luminosity, the lack of gamma-ray pulsations, the relatively hard and non-thermal spectrum of the pulsar, and its sine-like pulse profile, indicate a relatively small angle between the pulsar's spin and magnetic dipole axis. In this respect, it shares similar properties with a few other so-called MeV pulsars. Although the joint X-ray and TeV SED can be roughly described by a single-zone model, the obtained magnetic field value is unrealistically low. A more realistic scenario is the presence of a relic PWN, no longer emitting synchrotron X-rays but still radiating in TeV via inverse-Compton upscattering. We also serendipitously detected surprisingly bright X-ray emission from a very wide binary whose components should not be interacting.