Bamba's Group | 馬場研究室

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 …

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 …

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 …