Category Archives: Unclassified

A conference to showcase the XRISM’s performance and scientific results, and to discuss the future, has been held in Kyoto, Japan on Oct. 20–24 (XRISM 2025). It was an excellent experience to be there and to give a review talk on the plasma physics of supernova remnants. Many authorities in astronomy and astrophysics were thereContinue reading “XRISM international conference 2025 @Kyoto”

Our paper on the solar flare physics using the full performance of XRISM has been accepted for publication in PASJ (ADS). In its first ~2 years XRISM experienced a lot of solar flare events, which often made observable events in the detectors on XRISM. Although celestial observations are rarely affected, solar X-ray events are recordedContinue reading “XRISM solar flare paper”

We studied a TeV source without clear counterparts in other wavelengths but close to the supernova remnant G335.2+0.1 (Oka et al. 2025, ApJ; ADS). We used radio continuum, radio lines, X-rays, and gamma-rays to understand what is going on in this interesting system. What was unique was, in this system, we can trace some physicalContinue reading “Multi-wavelength study of a TeV-unidentified source near a supernova remnant”

The last XRISM team meeting was held in Leiden, Netherlands early July, 2025. Leiden was a beautiful city. We reviewed what we have learned with XRISM and what we can do in the future, later phase. I was happy to see that really a lot of scientific results are coming out, covering a broad rangeContinue reading “XRISM science meeting #8 in Leiden”

We held the 17th IACHEC meeting in Osaka, Japan. IACHEC is a consortium for international cross-calibration activities for X-ray detectors. More than 70 people attended from the US, Europe, China, Japan, etc. We are struggling to understand our own detectors by comparing own data with other detectors. Our recent major progress may include the understandingContinue reading “17th IACHEC meeting in Osaka!”

My new institute from this April is the University of Miyazaki, located in the southern part of Japan. Miyazaki is famous for many historical sites related to the creation myth of Japan. Here I will continue my work on astrophysics but also would like to broaden research topics.

Based on thermal plasma emission, we have estimated the shock velocities which produced the hot plasma in N132D. The resultant velocities are generally lower than those directly measured by a proper motion measurement, partly reaching a factor of four discrepancy. This may suggest that a large fraction of the shock kinetic energy was transferred toContinue reading “Highly efficient particle acceleration inferred in the supernova remnant N132D”

An internal team meeting of XRISM (SM7) has been held in Arizona, US. It was the best season for visitors and we had amazingly nice weather. Now that plenty of the science data have been collected, the entire XRISM team is working hard to publish bland new understanding of the universe. Every science team reportedContinue reading “XRISM science meeting #7 in Arizona”

Microquasar V4641 Sagitarii (Sgr) is now of great interest as an efficient cosmic-ray factory, because of the recent discovery of very high energy, extended gamma-ray emission around it with HAWC and LHAASO. Occasionally, XRISM observed this source on Sep 30 as a “generic ToO” target, following its recent outburst. The large field of view andContinue reading “Detection of extended X-rays around microquasar V4641 Sgr with XRISM”

Our XRISM paper on the supernova remnant Sagittarius A East (Sgr A East) has been accepted for publication in PASJ as a Letter (ADS). Sgr A East is a remnant located in a unique environment, the immediate vicinity (< a few pc) of the supermassive black hole of our Galaxy, Sgr A*. We are interestedContinue reading “XRISM Collaboration paper on the supernova remnant Sgr A East”