Suzaku Observation of G359.79-0.26, a New Supernova Remnant Candidate in the Galactic Center

Abstract

Utilizing Suzaku observations, we obtained the X-ray spectrum of G359.79-0.26, an extended X-ray feature nearby the Galactic center (GC) supernova remnant (SNR) SgrA East. We estimated the contribution from the Galactic center diffuse X-rays, which allows us a proper background subtraction from the faint extended source. A thin thermal plasma with a temperature of kT_e ∼ 1keV and slightly enhanced metal abundances (S and Ar) are required to reproduce the G359.79-0.26 spectrum. The absorption column density N_H ∼ 4 × 10²² cm^-2) associated with the plasma indicates that G359.79-0.26 is located in the GC. The thermal energy of the plasma is estimated to be 1.7 × 10⁵⁰erg, typical for galactic SNRs. Its center-filling X-ray emission surrounded by a shell-like radio structure suggests that G359.79-0.26 would be a new member of the mixed-morphology SNR class. The 2.45keV mosaic image covering a ∼ 40' × 40' GC field implies an alternative possibility that G359.79-0.26 might be a part of a large ring-like structure with a size of 18' × 16'.