Discovery of a highly energetic pulsar associated with IGR J14003-6326 in the young uncataloged galactic supernova remnant G310.6-1.6

Abstract

We report the discovery of 31.18ms pulsations from the INTEGRAL source IGR J14003-6326 using the Rossi X-ray Timing Explorer (RXTE). This pulsar is most likely associated with the bright Chandra X-ray point source lying at the center of G310.6-1.6, a previously unrecognized Galactic composite supernova remnant (SNR) with a bright central non-thermal radio and X-ray nebula, taken to be the pulsar wind nebula (PWN). PSR J1400-6325 is amongst the most energetic rotation-powered pulsars in the Galaxy, with a spin-down luminosity of ergs -1. In the rotating dipole model, the surface dipole magnetic field strength is Bs = 1.1 × 1012 G and the characteristic age kyr. The high spin-down power is consistent with the hard spectral indices of the pulsar and the nebula of 1.22 ± 0.15 and 1.83 ± 0.08, respectively, and a 2-10keV flux ratio F PWN/F PSR 8. Follow-up Parkes observations resulted in the detection of radio emission at 10 and 20cm from PSR J1400-6325 at a dispersion measure of 560cm-3pc, which implies a relatively large distance of 10 3kpc. However, the resulting location off the Galactic plane of 280 pc would be much larger than the typical thickness of the molecular disk, and we argue that G310.6-1.6 lies at a distance of 7kpc. There is no gamma-ray counterpart to the nebula or pulsar in the Fermi data published so far. A multi-wavelength study of this new composite SNR, from radio to very high-energy gamma rays, suggests a young (≲103yr) system formed by a sub-energetic (≲1050erg), low ejecta mass (M ej 3 M Ȯ) supernova explosion that occurred in a low-density environment (n 0 ∼ 0.01cm-3). © 2010. The American Astronomical Society. All rights reserved.