Discovery of an Energetic 38.5 ms Pulsar Powering the Gamma-ray Source IGR J18490-0000/HESS J1849-000

TL;DR

This paper reports the discovery of a young, energetic 38.5 ms pulsar PSR J1849-0001, associated with gamma-ray and X-ray sources, revealing insights into pulsar wind nebulae and TeV gamma-ray emission mechanisms.

Contribution

The discovery of PSR J1849-0001 and its detailed characterization, including its association with gamma-ray sources and PWN, provides new insights into pulsar energetics and emission models.

Findings

Pulsar has a period of 38.5 ms and a spin-down luminosity of 9.8E36 erg/s.

The pulsar is associated with a PWN and coincident with TeV gamma-ray source HESS J1849-000.

Spectral analysis supports leptonic models of TeV emission from PWNe.

Abstract

We report the discovery of a 38.5 ms X-ray pulsar in observations of the soft gamma-ray source IGR J18490-0000 with the Rossi X-ray Timing Explorer (RXTE). PSR J1849-0001 is spinning down rapidly with period derivative 1.42E-14 s/s, yielding a spin-down luminosity 9.8E36 erg/s, characteristic age 42.9 kyr, and surface dipole magnetic field strength 7.5E11 G. Within the INTEGRAL/IBIS error circle lies a point-like XMM-Newton and Chandra X-ray source that shows evidence of faint extended emission consistent with a pulsar wind nebula (PWN). The XMM-Newton spectrum of the point source is well fitted by an absorbed power-law model with photon index Gamma(PSR) = 1.1 +/- 0.2, N_H = (4.3+/-0.6)E22 cm^-2, and F(PSR;2-10keV) = (3.8+/-0.3)E-12 erg/s/cm^2, while the spectral parameters of the extended emission are Gamma(PWN) = 2.1 and F(PWN;2-10 keV) = 9E-13 erg/s/cm^2. IGR J18490-0000 is also coincident with the compact TeV source HESS J1849-000. For an assumed distance of 7 kpc in the Scutum arm tangent region, the 0.35-10 TeV luminosity of HESS J1849-000 is 0.13% of the pulsar's spin down energy, while the ratio F(0.35-10 TeV)/F(PWN; 2-10 keV) of approx. 2. These properties are consistent with leptonic models of TeV emission from PWNe, with PSR J1849-0001 in a stage of transition from a synchrotron X-ray source to an inverse Compton gamma-ray source.