Suzaku Observations across the Cygnus Loop from the Northeastern to the Southwestern Rim

Abstract

We have observed the Cygnus Loop from the northeast (NE) rim to the southwest (SW) rim using Suzaku in 10 pointings just north of previous XMM-Newton observations. The observation data obtained were divided into 45 rectangular regions where the width was configured so that each region would hold 8000-12000photons. The spectrum acquired from each region was fitted either with one-kT_e-component non-equilibrium ionization (NEI) model or with a two-kT_e-component NEI model. The two-kT_e-component model yielded a significantly better fit in almost all of the non-rim regions. Judging from the abundances and the flux, the high-kT_e-component (0.4-0.8keV) must be the ejecta origin, while the low-kT_e-component (∼0.3keV) comes from the swept-up matter. We found that the swept-up matter shell is very thin just southwest of center of the Loop. Together with previous observations, we estimated the diameter of this thin shell region to be 1°. We also found that the ejecta distributions were asymmetric to the geometric center: the ejecta of O, Ne, and Mg were distributed more in the NE, while the ejecta of Si and Fe were distributed more in the SW of the Cygnus Loop. We calculated the masses for various metals and estimated the origin of the Cygnus Loop as the a 12-15M_odot core-collapse explosion.