A. Sezer

Suzaku observation of the Galactic supernova remnant CTB 37A (G348.5+0.1)

In this paper, we present the results of the observations of CTB 37A obtained with the X-ray imaging spectrometer onboard the Suzaku satellite. The X-ray spectrum of CTB 37A is fitted well by two components: a single-temperature ionization equilibrium component (VMEKAL), with solar abundances, an electron temperature of kTe∼ 0.6 keV and an absorbing column density of NH∼ 3 × 1022 cm−2, and a power-law component with a photon index of Γ∼ 1.6. The X-ray spectrum of CTB 37A is characterized by clearly detected K-shell emission lines of Mg, Si, S and Ar. The plasma with solar abundances supports the idea that the X-ray emission originates from the shocked interstellar material. The ambient gas density and the age of the remnant are estimated to be ∼ 1f−1/2 cm−3 and ∼ 3 × 104f1/2 yr, respectively. The centre-filling X-ray emission, surrounded by a shell-like radio structure, and other X-ray properties indicate that this remnant could be a new member of the class of mixed-morphology supernova remnants.

RECOMBINING PLASMA IN THE GAMMA-RAY-EMITTING MIXED-MORPHOLOGY SUPERNOVA REMNANT 3C 391

A group of middle-aged mixed-morphology (MM) supernova remnants (SNRs) interacting with molecular clouds (MC) has been discovered as strong GeV gamma-ray emitters by Large Area Telescope on board Fermi Gamma Ray Space Telescope (Fermi-LAT). The recent observations of the Suzaku X-ray satellite have revealed that some of these interacting gamma-ray emitting SNRs, such as IC443, W49B, W44, and G359.1-0.5, have overionized plasmas. 3C 391 (G31.9+0.0) is another Galactic MM SNR interacting with MC. It was observed in GeV gamma rays by Fermi-LAT as well as in the 0.3

Suzaku study of the centrally brightened supernova remnant G272.2−3.2

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Suzaku observations of ejecta-dominated Galactic supernova remnant G346.6−0.2

10.0 keV X-ray band by Suzaku. In this work, 3C 391 was detected in GeV gamma rays with a significance of

A deep X-ray observation of the supernova remnant G304.6+0.1 (Kes 17) using Suzaku

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Recombining Plasma and Gamma-Ray Emission in the Mixed-morphology Supernova Remnant 3C 400.2

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SEARCHING FOR OVERIONIZED PLASMA IN THE GAMMA-RAY-EMITTING SUPERNOVA REMNANT G349.7+0.2

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Fe-RICH EJECTA IN THE SUPERNOVA REMNANT G352.7–0.1 WITH SUZAKU

and we showed that the GeV emission is point-like in nature. The GeV gamma-ray spectrum was shown to be best explained by the decay of neutral pions assuming that the protons follow a broken power-law distribution. We revealed radiative recombination structures of silicon and sulfur from 3C 391 using Suzaku data. In this paper we discuss the possible origin of this type of radiative plasma and hadronic gamma rays.

Suzakuanalysis of the supernova remnant G306.3−0.9 and the gamma-ray view of its neighbourhood

In this paper, we present the results from a Suzaku observation of the Galactic supernova remnant G272.2−3.2. The spectra of G272.2−3.2 are well fitted by a single-temperature variable abundance non-equilibrium ionization (VNEI) model with an electron temperature kTe∼ 0.77 keV, an ionization time-scale τ∼ 6.5 × 1010 cm−3 s and an absorbing column density NH∼ 1.1 × 1022 cm−2. We have detected enhanced abundances of Si, S, Ca, Fe and Ni in the centre region, indicating that the X-ray emission has an ejecta origin. We estimate that the electron density is ne∼ 0.48f−1/2 cm−3, the age is ∼4300f1/2 yr and the X-ray total mass is Mx= 475f1/2 M⊙ by taking the distance to be d= 10 kpc. To understand the origin of the centrally peaked X-ray emission of the remnant, we have studied the radial variations of the electron temperature and surface brightness. The relative abundances in the centre region suggest that G272.2−3.2 is the result of a Type Ia supernova explosion.

The first optical light from the supernova remnant G182.4+4.3 located in the Galactic anticentre region

We present here the results of the X-ray analysis of Galactic supernova remnant G346.6-0.2 observed with Suzaku. K-shell emission lines of Mg, Si, S, Ca and Fe are detected clearly for the first time. Strong emission lines of Si and S imply that X-ray emission nature of G346.6-0.2 is ejecta-dominated. The ejecta-dominated emission is well fitted with a combined model consisting of thermal plasma in non-equilibrium ionization and a non-thermal component, which can be regarded as synchrotron emission with a photon index of Γ ∼ 0.6. Absorbing column density of NH ∼ 2.1 × 10 22 cm is obtained from the best-fitting implying a high-density medium, high electron temperature of kTe ∼ 1.2 keV, and ionization timescale of net ∼ 2.9 × 10 11 cms indicating that this remnant may be far from full ionization equilibrium. The relative abundances from the ejecta show that the remnant originates from a Type Ia supernova explosion.