Search Publications
Suzaku Observations of Thermal and Non-Thermal X-Ray Emission from the Middle-Aged Supernova Remnant G156.2+5.7
Katsuda, Satoru; Petre, Robert; Yamaguchi, Hiroya +3 more
We present results from an X-ray analysis of a Galactic middle-aged supernova remnant (SNR), G156.2+5.7, which is bright and largely extended in X-ray wavelengths, showing a clear circular shape (radius ∼50'). Using the Suzaku satellite, we observed this SNR in three pointings: partially covering the northwestern rim, the eastern rim, and the cent…
Timing and Spectral Study of AXJ1745.6-2901 with Suzaku
Maeda, Yoshitomo; Makishima, Kazuo; Koyama, Katsuji +3 more
The eclipsing low-mass X-ray binary AX J1745.6-2901 was observed with Suzaku in its outburst phase. Combining the Chandra observation made 1.5 month earlier than Suzaku, we determined the orbital period to be 30063.76±0.14s. We found deep flux dips prior to the eclipse phase of the orbit. The X-ray spectrum of the persistent phase is described by …
Suzaku Observation of Diffuse X-Ray Emission from the Open Cluster Westerlund 2: a Hypernova Remnant?
Hayashida, Kiyoshi; Fujita, Yutaka; Takahara, Fumio +1 more
We present an analysis of Suzaku observations of the young open cluster Westerlund 2, which is filled with diffuse X-ray emission. We found that the emission consists of three thermal components, or two thermal and one non-thermal components. The upper limit of the energy flux of the non-thermal component is smaller than that in the TeV band obser…
Radial Velocity Search for Extrasolar Planets in Visual Binary Systems
Sato, Bun'ei; Itoh, Yoichi; Oasa, Yumiko +7 more
We searched for extrasolar planets in visual binary systems using precise Doppler-shift measurements taken over a period of 4 yr. Using the HIgh Dispersion Echelle Spectrograph (HIDES) equipped on the Okayama Astrophysical Observatory (OAO) 188cm reflector, we achieved a radial-velocity precision of about 10ms-1. We monitored both prima…
Optically Thick Outflows of Supercritical Accretion Discs: Radiative Diffusion Approach
Karpov, Sergey; Abolmasov, Pavel; Kotani, Taro
Highly supercritical accretion discs are probable sources of dense optically thick axisymmetric winds. We introduce a new approach based on diffusion approximation radiative transfer in a funnel geometry, and obtain an analytical solution for the energy density distribution inside the wind, assuming that all of the mass, momentum and energy are in…
Ejecta Distributions of Heavy Elements in the Cygnus Loop
Katsuda, Satoru; Uchida, Hiroyuki; Tsunemi, Hiroshi +2 more
We analyzed the metal distribution of the Cygnus Loop using 14 and 7 pointing observation data obtained by the Suzaku and XMM-Newton observatories, respectively. The spectral analysis shows that all of the spectra are well fitted by a two-kTe nonequilibrium ionization plasma model, as shown by earlier observations. From the best-fit par…
Evidence from the Extreme-Ultraviolet Imaging Spectrometer for Axial Filament Rotation before a Large Flare
Harra, Louise K.; Brooks, David H.; Hansteen, Viggo H. +2 more
In this article, we present observations made with the Extreme-ultraviolet Imaging Spectrometer on-board the Hinode solar satellite, of an active region filament in the HeII emission line at 256.32Å. The host active region AR 10930 produces an X-class flare during these observations. We measure Doppler shifts with apparent velocities of up to 20km…
Suzaku X-Ray Study of an Anomalous Source XSS J12270-4859
Ishida, Manabu; Tsujimoto, Masahiro; Ebisawa, Ken +1 more
We report on the results of a Suzaku X-ray observation of XSSJ12270-4859, one of the hard X-ray sources in the INTEGRAL catalogue. This object has been classified as an intermediate polar (IP) by its optical spectra, and a putative X-ray period of ∼860s. With a 30ks exposure by Suzaku, we obtained a well-exposed spectrum in the 0.2--70keV band. We…
Suzaku Observation of 30 Dor C: A Supernova Remnant with the Largest Non-Thermal Shell
Yamaguchi, Hiroya; Koyama, Katsuji; Bamba, Aya
This paper reports on the Suzaku results of thermal and non-thermal features of 30 Dor C, a supernova remnant (SNR) in a superbubble of the Large Magellanic Cloud (LMC). The west rim exhibits a non-thermal X-ray spectrum with no thermal component. A single power-law model is rejected, but a power-law model with spectral cutoff is accepted. The cut…
Time-Evolution of Peak Energy and Luminosity Relation within Pulses for GRB 061007: Probing Fireball Dynamics
Yamaoka, Kazutaka; Fukazawa, Yasushi; Nakagawa, Yujin E. +3 more
We performed a time-resolved spectral analysis of a bright, long gamma-ray burst GRB 061007 using Suzaku/WAM and Swift/BAT. Because of the large effective area of the WAM, we can investigate the time evolution of the spectral peak energy Etpeak and the luminosity Ltiso with 1-s time resolution, and we fi…