New Constraints on the Energetics, Progenitor Mass, and Age of the Supernova Remnant G292.0+1.8 Containing PSR J1124−5916

Abstract

We present spatially resolved spectroscopy of the supernova remnant (SNR) G292.0+1.8 with the Chandra X-Ray Observatory. This composite-type SNR contains the 135 ms pulsar, J1124-5916, recently discovered by Camilo and coworkers. We apply nonequilibrium ionization models to fit the ejecta-dominated regions and to identify the blast wave of the supernova explosion. By comparing the derived abundances with those predicted from nucleosynthesis models, we estimate a progenitor mass of 30-40 M solar. We derive the intrinsic parameters of the supernova explosion such as its energy, the age of the SNR, the blast wave velocity, and the swept-up mass. In the Sedov interpretation, our estimated SNR age of 2600 +250 -200 yr is close to the pulsar's characteristic age of 2900 yr. This confirms the pulsar/SNR association and relaxes the need for the pulsar to have a noncanonical value for the braking index, a large period at birth, or a large transverse velocity. We discuss the properties of the pulsar wind nebula (PWN) in the light of the Kennel & Coroniti model and estimate the pulsar wind magnetization parameter. We also report the first evidence for steepening of the power-law spectral index with increasing radius from the pulsar, a result that is expected from synchrotron losses and is reminiscent of Crab-like PWNe.