Spatially resolved spectroscopy of the Chandra field containing the supernova remnant G292.2-0.5.
GONZALEZ M. and SAFI-HARB S.
Abstract (from CDS):
We present observations with the Chandra Advanced CCD Imaging Spectrometer (ACIS-S) of the western interior of the supernova remnant (SNR) G292.2-0.5 associated with the high magnetic field pulsar (PSR) J1119-6127. Chandra's excellent resolution revealed 18 point sources on the S3 chip and allowed the study of the diffuse emission from G292.2-0.5 independently from these point sources. The diffuse emission from G292.2-0.5 can be adequately fitted with nonequilibrium ionization models; however, these fits result in an unrealistically high temperature (kT>3 keV), indicating the presence of a hard nonthermal component. By performing a spatially resolved spectroscopic study of the remnant, we identify the nonthermal emission as originating from the region closer to the pulsar. Its spectrum is well described with a power law with a photon index of Γ∼1-2. As a result of the flat spectrum and location close to the pulsar, we propose that this nonthermal emission arises from the injection of high-energy particles originating from PSR J1119-6127 and its pulsar wind nebula (PWN) into the SNR shell. As for the 18 point sources revealed by Chandra, only 3 sources have previously known counterparts at other wavelengths. Two of these sources exhibit enough counts to extract a spectrum, one being a new source CXOU J111911.8-613026 and the other being the X-ray counterpart of PSR J1119-6127 studied by us in a previous work. The spectrum of the new source CXOU J111911.8-613026 is soft (power-law photon index Γ∼3.6-4.6 or blackbody temperature kT∼0.2-0.36 keV) with a luminosity comparable to that of faint radio-quiet neutron stars. The nature of CXOU J111911.8-613026, however, cannot be determined with the present data and has to await further observations.