Yasunobu Uchiyama

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We present the results of our morphological and spectral study of properties of the supernova remnant RX J1713.7−3946 based on data obtained with XMM-Newton. Highly inhomogeneous structures, such as the bright spots, filaments and dark voids, noted by Uchiyama et al. (2003), appear in the entire bright western portion of the shell. In addition two narrow(More)
We present morphological and spectroscopic studies of the northwest rim of the supernova remnant RX J1713.7−3946 based on observations by the Chandra X-ray observatory. We found a complex network of nonthermal (synchrotron) X-ray filaments, as well as a 'void' type structure – a dim region of a circular shape – in the northwest rim. It is remarkable that(More)
We report on the discovery of a diffuse X-ray source with ASCA, presumably associated with a molecular cloud in the vicinity of the supernova remnant RX J1713.7−3946. The energy spectrum (1–10 keV) of the hard X-ray source shows a flat continuum, which is described by a power-law with a photon index of Γ = 1.0 +0.4 −0.3. We argue that this unusually flat(More)
The Hard X-ray Detector (HXD) on board Suzaku covers a wide energy range from 10 keV to 600 keV by combination of silicon PIN diodes and GSO scintillators. The HXD is designed to achieve an extremely low in-orbit background based on a combination of new techniques, including the concept of well-type active shield counter.
We report on the first detection of GeV high-energy gamma-ray emission from a young supernova remnant with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope. These observations reveal a source with no discernible spatial extension detected at a significance level of 12.2σ above 500 MeV at a location that is consistent with the position of(More)
Galactic cosmic rays (CRs) are widely believed to be accelerated by shock waves associated with the expansion of supernova ejecta into the interstellar medium. A key issue in this long-standing conjecture is a theoretical prediction that the interstellar magnetic field can be substantially amplified at the shock of a young supernova remnant (SNR) through(More)
We present Spitzer IRAC imaging of the large-scale jet in the quasar PKS 1136−135 at wavelengths of 3.6 and 5.8 µm, combined with previous VLA, HST, and Chandra observations. We clearly detect infrared emission from the jet, resulting in the most detailed multifrequency data among the jets in lobe-dominated quasars. The spectral energy distributions of the(More)
It is shown that the radio and gamma-ray emission observed from newly-found " GeV-bright" supernova remnants (SNRs) can be explained by a model, in which a shocked cloud and shock-accelerated cosmic rays (CRs) frozen in it are simultaneously compressed by the supernova blastwave as a result of formation of a radiative cloud shock. Simple reacceleration of(More)
  • Publ Astron, Soc, Japan, Yasunobu Uchiyama, Ryuichi Fujimoto, Shunsaku Okada +2 others
  • 2008
We present an empirical correction of sky coordinates of X-ray photons obtained with the X-ray Imaging Spectrometer (XIS) aboard the Suzaku satellite to improve the source position accuracy and restore the point-spread function (PSF). The XIS images are known to have an uncertainty in position of up to 1 ′ , and to show considerable degradations of the PSF.(More)
Recent discovery of the year-scale variability in the synchrotron X-ray emission of the supernova remnant (SNR) RX J1713.7−3946 has initiated our study of multi-epoch X-ray images and spectra of the young SNR Cassiopeia A based on the Chandra archive data taken in 2000, 2002, and 2004. We have found year-scale time variations in the X-ray intensity for a(More)