Welcome

We explore physics behind hot, energetic phenomena in the universe through a wide variety of telescopes including space-based X-ray observatories. Our research particularly focuses on high energy physical processes associated with supernova remnants, neutron stars, and black holes. We also develop new observational instruments for future satellite missions.

私たちは、宇宙X線観測衛星をはじめとする様々な望遠鏡の観測データを用いて、熱く激しい天体現象に潜む物理を突き止めようとしています。特に超新星残骸や中性子星・ブラックホールにおける高エネルギー物理過程を精力的に研究しています。また、将来の衛星搭載を目指して新しい観測機器の開発も進めています。

News

Paper

The paper by Mr. Masahiro Ichihashi has been accepted

The paper, “The electron temperature distribution and the high ionization just behind the shock in the Cygnus Loop”, by Masahiro Ichihashi(D3) has been accepted by ApJ. This paper analyzed the northeastern region of Cygnus Loop, one of the supernova remnants near the Earth, by XMM-Newton, the X-ray satellite with high spatial resolution. We showed that the electron temperature near the shock can be explained by the Sedov solution, the analytical solution for the temperature structure inside supernova remnants, indicating the small energy leakage near the slow shock, such as Cygnus Loop. We also showed the high ionization states just behind …

Paper

The paper by Dr. Hagino has been published in Nature.

The paper, “Structured ionized winds shooting out from a quasar at relativistic speeds,” by Dr. Hagino has been published online in Nature. In this paper, utilizing the excellent X-ray spectroscopic capability of the X-ray satellite XRISM, we discovered for the first time an unexpectedly complex velocity structure in the ultrafast outflow from the supermassive black hole PDS 456, expelling heavy ions with velocities of 30% of the speed of light. This complex velocity structure indicates a highly inhomogeneous clumpy structure of the outflow, in contrast to the previous assumption of a homogeneous flow. Considering this clumpy structure, the kinetic power …

Paper

The paper by Dr. Aya Bamba has been accepted for PASJ.

The paper ‘Measuring the asymmetric expansion of the Fe ejecta of Cassiopeia A with XRISM/Resolve’, by Dr. Bamba, has been accepted for publication in the special XRISM issue of the journal PASJ. In this paper, we observed the supernova remnant Cassiopeia A (Cas A), which is about 350 years old, with XRISM, which has excellent energy resolution, We showed that the plasma containing iron elements shows red-shift in the north-east and blue-shift in the south-west. From these observational facts we have identified that in Cas A fragments of the pre-explosion star are scattered in non-isotropic directions. These results are consistent …

Paper

The paper by Dr. Dai Tateishi has been accepted for PASJ.

The paper titled “Study of the Origin of the Azimuthal Variation of Synchrotron X-ray Spectrum from SNR RX J0852.0-4622,” authored by Dr. Dai Tateishi from the Bamba lab, has been accepted for PASJ. In this study, the authors compared the spatial distribution of the X-ray spectrum of SNR RX J0852.0-4622 with the distribution of molecular cloud density and shock velocity. The results indicate a positive correlation between molecular cloud density and X-ray flux throughout the SNR. Additionally, a positive correlation was found between X-ray flux and shock velocity in the southern region of the SNR. Based on these findings, the …

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