Search Publications
Revisiting the Suzaku spectrum of the Galactic SNR W 49B: Non-detection of iron K-shell charge-exchange emission and refined ejecta-mass ratios of iron-group elements
Sato, Toshiki; Sawada, Makoto; Maeda, Keiichi +1 more
The origin of the recombining plasma in several Galactic SNRs has been debated. A plausible mechanism would be a rapid cooling in the past, by either an adiabatic or a conductive process. A recent spectral study of W 49B reported a possible charge-exchange emission due to collisions between the shock-heated ejecta and cold clouds, which could be d…
Detection of the neutral iron line from the supernova remnant W 49 B with Suzaku
Katsuda, Satoru; Nobukawa, Masayoshi; Nobukawa, Kumiko K. +2 more
Recent studies of supernova remnants (SNRs) have revealed that some SNRs exhibit a neutral iron line emission at 6.4 keV. This line has been proposed to originate from the interaction of high-energy particles formed in the SNR shell with the surrounding cold matter. We searched for the neutral iron line emission in the SNR W 49 B. Significant dete…
Multi-epoch X-ray spectral analysis of Centaurus A: Revealing new constraints on iron emission line origins
Tanimoto, Atsushi; Bamba, Aya; Hagino, Kouichi +3 more
We conduct X-ray reverberation mapping and spectral analysis of the radio galaxy Centaurus A to uncover its central structure. We compare the light curve of the hard X-ray continuum from Swift Burst Alert Telescope observations with that of the Fe K
Suzaku observation of an iron K-shell line in the spiral galaxy NGC 6946
Yamauchi, Shigeo; Inaba, Azusa; Anraku, Yumiko
An emission line at ~6.7 keV is attributable to an He-like iron K-shell transition, which indicates existence of a thin thermal plasma with a temperature of several keV. Using Suzaku archival data, we searched for the iron K-line from the spiral galaxy NGC 6946, and found it at 6.68 ± 0.07 keV at the 3.1σ level in the central $r\le {2.^{\prime }5}…
Plasma diagnostics of supernova remnant 3C 400.2 by Suzaku observations
Nobukawa, Masayoshi; Uchiyama, Hideki; Nobukawa, Kumiko K. +2 more
We report on the results of plasma diagnostics of the supernova remnant (SNR) 3C 400.2, which has been reported to have a recombining plasma by previous studies. For careful background estimation, we simultaneously fitted spectra extracted from the SNR and background regions and evaluated the SNR emission contaminating the background-region spectr…
Dark matter search in the Perseus cluster with simultaneous analysis of Hitomi and Suzaku data
Kitamoto, Shunji; Sawada, Makoto; Tamura, Takayuki +1 more
The reported detection of a 3.5 keV emission line in the Perseus cluster, possibly originating from dark matter decay, is still under scrutiny. Despite extensive observations, the detection has not yet been confirmed, and its origin remains a topic of active debate. Most of the previous searches relied on spectroscopy with X-ray charge-coupled dev…
The soft X-ray background with Suzaku. II. Supervirial temperature bubbles?
Sato, Kosuke; Yamasaki, Noriko Y.; Matsushita, Kyoko +4 more
Observations of the hot X-ray emitting interstellar medium in the Milky Way are important for studying the stellar feedback and for understanding the formation and evolution of galaxies. We present measurements of the soft X-ray background emission for 130 Suzaku observations at 75° < l < 285° and |b| > 15°. With the standard soft X-ray b…
Spectral analysis of the Galactic supernova remnant Kesteven 69 with Suzaku
Yamauchi, Shigeo; Pannuti, Thomas G.
The results of a Suzaku observation of the supernova remnant (SNR) Kesteven 69 = G21.8-0.6 are presented. To estimate the sky background precisely, we conducted a simultaneous fit of the source region spectrum with the background region spectrum and found that the SNR spectrum is well represented by a two-component ionizing plasma model composed o…
Suzaku spectral analysis of an X-ray emitting plasma in the supernova remnant G352.7-0.1
Nobukawa, Masayoshi; Nobukawa, Kumiko K.; Yamauchi, Shigeo +1 more
The results of a Suzaku observation of the supernova remnant (SNR) G352.7-0.1 are presented in this paper. We conducted spectral analysis based on careful sky background estimation and found an emission line from Al at 1.6 keV, in addition to previously detected emission lines from Mg, Si, S, Ar, Ca, and Fe ions. The X-ray spectrum in the 0.7-10 k…
Suzaku and Chandra study of diffuse X-ray emission from the massive star-forming region RCW 38
Ezoe, Yuichiro; Odaka, Hirokazu; Fukushima, Aoto
In some massive star-forming regions, diffuse X-ray emission has been observed. It can be classified as thermal emission from sub- or several-keV plasmas, non-thermal emission represented by the power law, or a mixture of them. We have studied the nearby (~1.7 kpc) young massive star-forming region RCW 38. In a previous study, non-thermal diffuse …