In this paper, we investigated the Fe K-shell lines in the supernova remnant W51C and hard X-ray sources in the proximity. We measured the intensities of Fe I K$α$ and Fe XXV He$α$ lines at 6.40 keV and 6.68 keV, respectively, and found that the intensity of the 6.68 keV line is consistent with the background level expected from previous studies, while that of the 6.40 keV line is higher at the significance level of 2.0$σ$. Given the presence of gamma-ray emission and high ionization rate point spatially coincident with the remnant, we conclude that the enhanced 6.40 keV line most likely originates from the interaction between low-energy cosmic rays and molecular clouds. Also, we discovered an enhanced 6.68 keV line emission from the compact H II region G49.0-0.3 at the significance level of 3.4$σ$. Spectral analysis revealed that the temperature and abundance of the thermal plasma with the 6.68 keV line is $kT = 3.0^{+0.8}_{-0.7}$ keV and $Z = 0.5 \pm 0.2$ solar, respectively. These values are explained by the thermal plasma generated by the stellar winds of O stars.
The Galactic supernova remnant (SNR) MSH 15-56 is a member of the class of composite SNRs that consists of the remnant shell and a displaced pulsar wind nebula (PWN). The earlier X-ray observations reported the comet-like morphology of the PWN and the ejecta distribution of the SNR. In this work, we present a study of MSH 15-56 using archival Suzaku data. We investigate the nature of the emission and spectral parameters of the remnant. The X-ray spectra are well fitted with a combination of a thermal and non-thermal model with temperature ~0.6 keV and photon index ~2.0. The slightly enhanced a…
X-Ray Observation of the Galactic Supernova Remnant G355.6-0.0 with Suzaku
我们介绍了银河系超新星遗迹（SNR）G355.6-0.0观测朱雀。我们将ASCA探测到的漫射发射分解为两个物体，G355.6-0.0和一个点状源，朱雀J173530-3236。来自G355.6-0.0的X射线发射在射电壳层内呈现出中心填充的形态。X射线谱很好地代表了一个薄的热等离子体模型与增强的金属丰度。G355.6-0.0的空间和光谱特性表明它属于混合形态信噪比。约6 x 10^{22} cm^{-2}的NH值支持G355.6-0.0是远距离SNR。朱雀J173530-3236的硬X射线谱中有一条强的Fe发射线，与激变变星的发射线相似。约3 x 10^{22} cm^{-2}的NH值小于G355.6-0.0的NH值，因此朱雀J173530-3236位于G355.6-0.0的近侧。
Ages of the magnetar 1E 2259+586 and the associated supernova remnant CTB~109 were studied. Analyzing the Suzaku data of CTB~109, its age was estimated to be $\sim$14~kyr, which is much shorter than the measured characteristic age of 1E 2259+586, 230 kyr. This reconfirms the previously reported age discrepancy of this magnetar/remnant association, and suggests that the characteristic ages of magnetars are generally over-estimated as compared to their true ages. This discrepancy is thought to arise because the former are calculated without considering decay of the magnetic fields. This novel vi…
We present the results of an X-ray spectral analysis of the northeast region of the candidate supernova remnant G189.6+3.3 with Suzaku. K-shell lines from highly ionized Ne, Mg, Si, and S were detected in the spectrum for the first time. In addition, a radiative recombining continuum (RRC) from He-like Si was clearly seen near 2.5 keV. This detection of an RRC reveals for the first time that G189.6+3.3 possesses an X-ray-emitting recombining plasma (RP). The extracted X-ray spectrum in the 0.6-10.0 keV energy band is well fitted with a model consisting of a collisional ionization equilibrium p…
G1.9+0.3 is the youngest known Galactic supernova remnant (SNR) and dominated by X-ray synchrotron emission. Synchrotron X-rays can be a useful tool to study the electron acceleration in young SNRs. The X-ray spectra of young SNRs give us information about the particle acceleration at the early stages of evolution of SNRs. In this work, we investigate the time evolution of roll-off frequency of the synchrotron spectrum from SNR G1.9+0.3 using Suzaku. For this analysis, we use ~101 ks (2011) and ~92 ks (2015) observations with the X-ray Imaging Spectrometer. We find that there are no significan…
We analyze the Suzaku XIS data of the central region of supernova remnant G332.5-5.6. The X-ray data are well described by a single non-equilibrium ionization thermal model, {\tt vnei}, with an absorbing hydrogen column density of 1.4$^{+0.4}_{-0.1}$ $\times$ 10$^{21}$ cm$^{-2}$. The plasma is characterized by an electron temperature of 0.49$^{+0.08}_{-0.06}$ keV with subsolar abundances for O (0.58$^{+0.06}_{-0.05}$ solar value) and Fe (0.72$^{+0.06}_{-0.05}$ solar value) and slightly overabundance for Mg (1.23$^{+0.14}_{-0.14}$ solar value). It seems that the central X-ray emission originate…
We report re-analyses of the Suzaku observations of the Galactic supernova remnant (SNR), G272.2$-$3.2, for which the previous studies were limited below 3 keV. With careful data reduction and background subtraction, we discover the K-shell lines of Ar, Ca, and Fe above 3 keV. The X-ray spectrum of G272.2$-$3.2 consists of two components, a low-temperature collisional ionization equilibrium (CIE) plasma ($kT_{\rm e} \sim 0.2$ keV) and a high-temperature non-equilibrium ionization (NEI) plasma ($kT_{\rm e} = 0.6$-$3$ keV). The CIE plasma has solar abundances over the entire area, hence it would…
Diffusive shock acceleration by the shockwaves in supernova remnants (SNRs) is widely accepted as the dominant source for Galactic cosmic rays. However, it is unknown what determines the maximum energy of accelerated particles. The surrounding environment could be one of the key parameters. The SNR RCW 86 shows both thermal and non-thermal X-ray emission with different spatial morphologies. These emission originate from the shock-heated plasma and accelerated electrons respectively, and their intensities reflect their density distributions. Thus, the remnant provides a suitable laboratory to t…
We present an investigation of the supernova remnant (SNR) G306.3$-$0.9 using archival multi-wavelength data. The Suzaku spectra are well described by two-component thermal plasma models: The soft component is in ionization equilibrium and has a temperature $\sim$0.59 keV, while the hard component has temperature $\sim$3.2 keV and ionization time-scale $\sim$$2.6\times10^{10}$ cm$^{-3}$ s. We clearly detected Fe K-shell line at energy of $\sim$6.5 keV from this remnant. The overabundances of Si, S, Ar, Ca, and Fe confirm that the X-ray emission has an ejecta origin. The centroid energy of the …
We present an X-ray study of the mixed-morphology supernova remnant CTB 1 (G116.9+0.2) observed with Suzaku. The 0.6-2.0 keV spectra in the northeast breakout region of CTB 1 are well represented by a collisional ionization-equilibrium plasma model with an electron temperature of ~ 0.3 keV, whereas those in the southwest inner-shell region can be reproduced by a recombining plasma model with an electron temperature of ~ 0.2 keV, an initial ionization temperature of ~ 3 keV, and an ionization parameter of ~ 9 $\times$ 10$^{11}$ cm$^{-3}$s. This is the first detection of the recombining plasma i…
Kes 69 is a mixed-morphology (MM) supernova remnant (SNR) that is known to be interacting with molecular clouds based on 1720 MHz hydroxyl (OH) maser emission observations in the northeastern and southeastern regions. We present an investigation of Kes 69 using $\sim$67 ks Suzaku observation. The X-ray spectrum of the whole SNR is well fitted by a non-equilibrium ionization model with an electron temperature of $kT_{\rm e}$ $\sim$ 2.5 keV, ionization time-scale of $τ$ $\sim$ 4.1$\times10^{10}$ cm$^{-3}$ s and absorbing column density of $N_{\rm H}$ $\sim$ 3.1$\times10^{22}$ cm$^{-2}$. We clear…
We present the first dedicated X-ray study of the supernova remnant (SNR) G32.8-0.1 (Kes 78) with Suzaku. X-ray emission from the whole SNR shell has been detected for the first time. The X-ray morphology is well correlated with the emission from the radio shell, while anti-correlated with the molecular cloud found in the SNR field. The X-ray spectrum shows not only conventional low-temperature (kT ~ 0.6 keV) thermal emission in a non-equilibrium ionization state, but also a very high temperature (kT ~ 3.4 keV) component with a very low ionization timescale (~ 2.7e9 cm^{-3}s), or a hard non-th…
Typing the origin (i.e., Type Ia or core-collapse) of supernova remnants (SNRs) is crucial to determine the rates of supernova (SN) explosions in a galaxy, which is a key to understand its recent chemical evolution. However, evolved SNRs in the so-called Sedov phase are dominated by the swept-up interstellar medium (ISM), making it difficult to determine their ejecta composition and thus SN type. Here we present a systematic X-ray study of nine evolved SNRs in the Magellanic Clouds, DEM L238, DEM L249, 0534-69.9, 0548-70.4, B0532-71.0, B0532-67.5, 0103-72.6, 0049-73.6, and 0104-72.3, using arc…
3C 396 is a composite supernova remnant (SNR), consisting of a central pulsar wind nebula (PWN) and a bright shell in the west, which is known to be interacting with molecular clouds (MCs). We present a study of X-ray emission from the shell and the PWN of the SNR 3C 396 using archival Suzaku data. The spectrum of the SNR shell is clearly thermal, without a signature of a non-thermal component. The abundances of Al and Ca from the shell are slightly enhanced, which indicates the presence of metal-enriched supernova ejecta. The PWN spectra are well described by a power-law model with a photon i…
This paper reports results of a Suzaku observation of the supernova remnant (SNR) Kes 79 (G33.6+0.1). The X-ray spectrum is best fitted by a two-temperature model: a non-equilibrium ionization (NEI) plasma and a collisional ionization equilibrium (CIE) plasma. The NEI plasma is spatially confined within the inner radio shell with kT~0.8 keV, while the CIE plasma is found in more spatially extended regions associated with the outer radio shell with kT~0.2 keV and solar abundance. Therefore, the NEI plasma is attributable to the SN ejecta and the CIE plasma is forward shocked interstellar medium…
Suzaku Observations of the Great Annihilator and the Surrounding Diffuse Emissions
我们报告了朱雀观测的1 E 1740.7-2942，一个黑洞候选者称为“大湮灭者”（GA）。朱雀的高质量的光谱提供了最严格的约束的遗传算法的参数。在6.4keV的FeI K α和2.45keV的SXV K α的线像中，在GA周围发现了两个团簇结构。一个名为M359.23-0.04的团簇显示出6.4 keV的谱线，等效宽度约为1.2 keV，在射电CS（J=1-0）图中与分子云有关。因此，来自M359.23-0.04的6.4 keV谱线可能是由于外部X射线源照射的X射线荧光。辐射的X射线可能是人马座A* 过去的耀斑，也可能是附近明亮的源GA。另一个名为G359.12-0.05的星团与射电超新星遗迹候选者G359.07-0.02有关。因此，我们认为G359.12-0.05是G359.07-0.02的X射线对应物。G359.12-0.05具有温度为kT ~ 0.9 keV的薄热等离子体光谱。G359.12-0.05的等离子体参数与银河系中心区域单个超新星遗迹的参数一致。
3C 400.2 belongs to the mixed morphology supernova remnant class, showing center-filled X-ray and shell-like radio morphology. We present a study of 3C 400.2 with archival Suzaku and Fermi-LAT observations. We find recombining plasma (RP) in the Suzaku spectra of north-east and south-east regions. The spectra of these regions are well described by two-component thermal plasma models: The hard component is in RP, while the soft component is in collisional ionization equilibrium (CIE) conditions. The RP has enhanced abundances indicating that the X-ray emission has an ejecta origin, while the CI…
We present the results from the Suzaku X-ray Imaging Spectrometer observation of the mixed-morphology supernova remnant (SNR) HB9 (G160.9+2.6). We discovered recombining plasma (RP) in the western Suzaku observation region and the spectra here are well described by a model having collisional ionization equilibrium (CIE) and RP components. On the other hand, the X-ray spectra from the eastern Suzaku observation region are best reproduced by the CIE and non-equilibrium ionization model. We discuss possible scenarios to explain the origin of the RP emission based on the observational properties a…
X-ray observations of supernova remnants (SNRs) allow us to investigate the chemical inhomogeneity of ejecta, offering unique insight into the nucleosynthesis in supernova explosions. Here we present detailed imaging and spectroscopic studies of the "Fe knot" located along the eastern rim of the Type Ia SNR Tycho (SN 1572) using Suzaku and Chandra long-exposure data. Surprisingly, the Suzaku spectrum of this knot shows no emission from Cr, Mn, or Ni, which is unusual for the Fe-rich regions in this SNR. Within the framework of the canonical delayed-detonation models for SN Ia, the observed mas…
We report the results of Suzaku observations of the young supernova remnant, Vela Jr.\ (RX J0852.0$-$4622), which is known to emit synchrotron X-rays, as well as TeV gamma-rays. Utilizing 39 Suzaku mapping observation data from Vela Jr., a significant hard X-ray emission is detected with the hard X-ray detector (HXD) from the north-west TeV-emitting region. The X-ray spectrum is well reproduced by a single power-law model with the photon index of 3.15$^{+1.18}_{-1.14}$ in the 12--22 keV band. Compiling this with the soft X-ray spectrum simultaneously observed with the X-ray imaging spectromete…
We investigate the damping of Alfvén waves generated by the cosmic ray resonant streaming instability in the context of the cosmic ray escape and propagation in the proximity of supernova remnants. We consider ion-neutral damping, turbulent damping and non linear Landau damping in the warm ionized and warm neutral phases of the interstellar medium. For the ion-neutral damping, up-to-date damping coefficients are used. We investigate in particular whether the self-confinement of cosmic rays nearby sources can appreciably affect the grammage. We show that the ion-neutral damping and the turbulen…
We report the first robust detection of the hard X-ray emission in the 15--30\,keV band from Kepler's supernova remnant with the silicon PIN-type semiconductor detector of the hard X-ray detector (HXD-PIN) onboard Suzaku. The detection significance is 7.17 $σ$ for the emission from Kepler's entire X-ray emitting region. The energy spectrum is found to be well reproduced by a single power-law function with a photon index of $3.13^{+1.85+0.69}_{-1.52-0.36}$, where the first and second errors represent 90\%-statistical and systematic errors, respectively. The X-ray flux is determined to be 2.75$_…
Supernova Remnant RX J1713.7-3946 emits synchrotron X-rays and very high energy $γ$-rays. Recently, thermal X-ray line emission is detected from ejecta plasma. CO and HI observations indicate that a highly inhomogeneous medium surrounding the SNR. It is interacting with dense molecular clouds in the northwest and the southwest of the remnant. The origin of the $γ$-ray emission from RX J1713.7-3946 is still uncertain. Detection of rapid variability in X-ray emission from RX J1713.7-3946 indicates the magnetic field $B$ $\sim$ mG. In this work, we investigate the time variation in X-ray flux, lu…
The unidentified VHE (E>100 GeV) gamma-ray source HESS J1507-622 seems to not fit into standard models for sources related to young supernova remnants, pulsar wind nebulae, or young stellar populations in general. This is due to its intrinsically extended, but yet compact morphology, coupled with a relative large offset (~3.5 deg) from the Galactic plane. Therefore, it has been suggested that this object may be the first representative of a new distinct class of extended off-plane gamma-ray sources. The distance to HESS J1507-622 is the key parameter to constrain the source's most important pr…
The explosive origin of the young supernova remnant (SNR) 3C 397 (G41.1-0.3) is debated. Its elongated morphology and proximity to a molecular cloud are suggestive of a core-collapse (CC) SN origin, yet recent X-ray studies of heavy metals show chemical yields and line centroid energies consistent with a Type Ia SN. In this paper, we analyze the full X-ray spectrum from 0.7-10 keV of 3C 397 observed with Suzaku and compare the line centroid energies, fluxes, and elemental abundances of intermediate-mass and heavy metals (Mg to Ni) to Type Ia and CC hydrodynamical model predictions. Based on th…
HESS J1841$-$055 is a diffuse unidentified gamma-ray source with the size of $\sim\,1.3^{\circ}\times\,1^{\circ}$. No conclusive counterpart in other wavelengths has so far detected. To search for X-rays responsible for the TeV emission, the Suzaku observations were conducted, which covered a half region of the HESS source. In the soft band (0.5-2.0 keV), we discovered a diffuse emission, Suzaku J1840.2$-$0552, with the size of $\sim10'$. Since its spectrum was fitted by an optically thin thermal plasma model, Suzaku J1840.2$-$0552 is likely to be a supernova remnant. We also discovered an ext…
