X-ray observations of the W51 complex with suzaku

Abstract

We present a detailed analysis of X-ray emission from the middle-aged supernova remnant W51C and starforming region W51 B with Suzaku. The soft X-ray emission from W51 C is well-represented by an optically thin thermal plasma in a non-equilibrium ionization state with a temperature of ∼0.7 keV. The elemental abundance of Mg is significantly higher than the solar value. We find no significant feature of an over-ionized plasma in W51 C. The hard X-ray emission is spatially coincident with the molecular clouds associated with W51 B, overlapping with W51C. The spectrum is represented by an optically thin thermal plasma with a temperature of ∼5 keV, or a powerlaw model with a photon index of ∼2.2. The emission probably has a diffuse nature, since its luminosity of 1 × 1034 erg s-1 in the 0.5-10 keV band cannot be explained by any emission from point sources in this region. We discuss the possibility that the hard X-ray emission comes from stellar winds of OB stars in W51 B, or accelerated particles in W51 C. © 2013 Astronomical Society of Japan.