The XIS is an X-ray Imaging Spectrometer system, consisting of state-of-the-art charge-coupled devices (CCDs) optimized for X-ray detection, camera bodies, and control electronics. Four sets of XIS sensors are placed at the focal planes of the grazing-incidence, nested thin-foil mirrors (XRT: X-Ray Telescope) onboard the Suzaku satellite. Three of the XIS sensors have front-illuminated CCDs, while the other has a back-illuminated CCD. Coupled with the XRT, the energy range of 0.2-12 keV with energy resolution of 130 eV at 5.9 keV, and a field of view of 18 × 18 are realized. Since the Suzaku launch on 2005 July 10, the XIS has been functioning well.

High-sensitivity wide-band X-ray spectroscopy is the key feature of the Suzaku X-ray observatory, launched on 2005 July 10. This paper summarizes the spacecraft, in-orbit performance, operations, and data processing that are related to observations. The scientific instruments, the high-throughput X-ray telescopes, X-ray CCD cameras, non-imaging hard X-ray detector are also described.

Supernova remnants (SNRs) retain crucial information about both their parent explosion and circumstellar material left behind by their progenitor. However, the complexity of the interaction between supernova ejecta and ambient medium often blurs this information, and it is not uncommon for the basic progenitor type (Ia or core-collapse) of well-studied remnants to remain uncertain. Here we present a powerful new observational diagnostic to discriminate between progenitor types and constrain the ambient medium density of SNRs using solely Fe K-shell X-ray emission. We analyze all extant Suzaku observations of SNRs and detect Fe Kα emission from 23 young or middle-aged remnants, including five first detections (IC 443, G292.0+1.8, G337.2-0.7, N49, and N63A). The Fe Kα centroids clearly separate progenitor types, with the Fe-rich ejecta in Type Ia remnants being significantly less ionized than in core-collapse SNRs. Within each progenitor group, the Fe Kα luminosity and centroid are well correlated, with more luminous objects having more highly ionized Fe. Our results indicate that there is a strong connection between explosion type and ambient medium density, and suggest that Type Ia supernova progenitors do not substantially modify their surroundings at radii of up to several parsecs. We also detect a K-shell radiative recombination continuum of Fe in W49B and IC 443, implying a strong circumstellar interaction in the early evolutionary phases of these core-collapse remnants.

We present results obtained from a series of observations of the supernova remnant RX J1713.7−3946 by the Suzaku satellite which cover about two-thirds of the remnant surface. Hard X-rays have been detected from each pointing up to ∼ 40 keV. The hard X-ray spectra are described by power-law functions with photon indices of ∼ 3.0, which are larger than those in the energy region below 10 keV. The combination of the spatially-integrated XIS and HXD spectra clearly reveals a spectral cutoff in the X-ray spectrum which is linked to the maximum energy of accelerated electrons emitting synchrotron radiation. The broad-band coverage of Suzaku observations from 0.4 keV to 40 keV allows us to derive, for the first time, the energy spectrum of parent electrons in the cutoff region. The inferred cutoff energy in the spatially-integrated X-ray spectrum indicates that the electron acceleration in the remnant proceeds close to the Bohm-diffusion limit. We discuss implications of the spectral and morphological properties of Suzaku data in the context of the origin of nonthermal emission. The Suzaku X-ray and the H.E.S.S. TeV gamma-ray data together hardly can be explained within a pure leptonic scenario, unless we introduce an additional component of relativistic electrons with softer energy spectrum. Moreover, the leptonic models require very weak magnetic field which does not agree with the recently discovered filamentary structure and short-term variability features of the X-ray emitting region. The hadronic models with strong magnetic field provide perfect fits to the observed X-ray and TeV gamma-ray spectra through the synchrotron radiation of electrons and p-p interactions of protons, but require special arrangements of model parameters to explain the lack of thermal component of X-ray emission. For the morphology studies, we compare the X-ray an TeV gama-ray surface brightness maps using the Suzaku XIS and the H.E.S.S. data. We confirm the previously reported strong correlation between X-ray and TeV gammaray emission components. At the same time the Suzaku data reveal a deviation from the general tendency, namely, the X-ray emission in the western rim regions appears brighter than expected from the average X-ray to gamma-ray ratio. Subject headings: acceleration of particles -ISM: individual(RX J1713.7−3946) -ISM: supernova remnants -X-rays: ISM

Supernova remnants ($=$ SNR) are suggested to be sites of cosmic-ray acceleration. In particular, it has been an issue of keen interest whether cosmic ray protons are being accelerated in a SNR which emits TeV $\gamma$-rays. A crucial observational test for this is to find dense molecular gas towards the SNR, because such molecular gas can best verify the existence of cosmic-ray protons via pion decay to $\gamma$-rays. Here, we show that new high-resolution mm-wave observations of interstellar CO molecule have revealed molecular gas at 1 kpc distance interacting with the TeV $\gamma$-ray SNR G 347.3$-$0.5, and that a molecular cloud of $\sim 200$ solar masses is clearly associated with the TeV $\gamma$-ray peak, providing strong evidence for proton acceleration. We have estimated the total energy of accelerated protons to be $\sim 1048 \,\mathrm{erg}$, which corresponds to an acceleration efficiency of $\sim 0.001$, posing an observational constraint on the proton acceleration.