F. Gök

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.

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

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.

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

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.

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

In this paper, we present the analysis of a deep (99.6 ks) observation of G304.6+0.1 with the X-ray Imaging Spectrometer on board the Suzaku satellite. The X-ray spectral data are well fitted with a plasma model consisting of a thermal component, in collisional ionization equilibrium, and a non-thermal component. The thermal emission is well fitted with the vmekal model with an electron temperature of kTe∼ 0.75 keV, a high absorbing column density of NH∼ 3.9 × 1022 cm−2 and near/lower solar abundances, which indicate that the X-ray emitting plasma of G304.6+0.1 is dominated by a swept-up ambient medium. The non-thermal component is well fitted with a power-law model with a photon index of Γ∼ 1.4. We have found a relatively high electron density ne∼ 2.3f−1/2 cm−3, an age t∼ 1.4 × 104f1/2 yr and an X-ray emitting mass Mx∼ 380f1/2 M⊙ at an adopted distance of d= 10 kpc. Using the morphological and spectral X-ray data, we confirm that the remnant is a new member of the mixed-morphology supernova remnants.

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

G349.7+0.2 is a supernova remnant (SNR) expanding in a dense medium of molecular clouds and interacting with clumps of molecular material emitting gamma-rays. We analyzed the gamma-ray data of the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope and detected G349.7+0.2 in the energy range of 0.2–300 GeV with a significance of ∼13σ, showing no extended morphology. Modeling of the gamma-ray spectrum revealed that the GeV gamma-ray emission dominantly originates from the decay of neutral pions, where the protons follow a broken power-law distribution with a spectral break at ∼12 GeV. To search for features of radiative recombination continua in the eastern and western regions of the remnant, we analyzed the Suzaku data of G349.7+0.2 and found no evidence for overionized plasma. In this paper, we discuss possible scenarios to explain the hadronic gamma-ray emission in G349.7+0.2 and the mixed morphology nature of this SNR.

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

In this work, we present results from a

Optical observations of the galactic supernova remnants G59.5+0.1, G84.9+0.5 and G67.7+1.8

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Ejecta detection in the middle-aged Galactic supernova remnant G296.1−0.5 observed with Suzaku

201.6 ks observation of G352.7

Optical imaging and spectroscopic observation of the galactic supernova remnant G85.9-0.6

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Suzaku and Fermi observations of the supernova remnant G1.9 + 0.3

0.1 by using the X-ray Imaging Spectrometer onboard {\it Suzaku} X-ray Observatory. The X-ray emission from the remnant is well described by two-temperature thermal models of non-equilibrium ionization with variable abundances with a column density of