談話会
Colloquium

山田 智史（東北大学）
Accretion and Multi-scale Ejection Resolved by X-ray Observations from 1999 to 2025
To make a database of multiphase (e.g., ionized/dusty/neutral/molecular) outflows, we have launched a new project, X-ray Winds In Nearby-to-distant Galaxies (X-WING). As the first study of the X-WING project, we constructed a sample of 132 AGNs in z ~ 0-4 exhibiting blueshifted absorption lines of X-ray winds reported by the end of 2023. With a thorough investigation of the previous works, we created the database of outflow properties of 583 X-ray winds, including outflow velocities (Vout), outflow radii (Rout), and mass/kinetic outflow rates (Mout/Eout). The ultrafast outflows (UFOs) and slower warm absorbers cover the Vout range of ~100 to 100,000 km/s. Interestingly, we found a clear velocity gap around Vout ~ 10,000 km/s. Although the gap can be an artifact due to the confusion of the emission/absorption lines and Fe K edge in the 6-7 keV band, there is another possibility that the UFOs and galactic-scale outflows are physically disconnected. Moreover, we introduce our unprecedented high-energy-resolution spectra with XRISM operated from 2023 and provide new insights into the origin of the Vout gap and the plausible multi-scale structure of X-ray winds (e.g., Yamada+24b, ApJS; XRISM Collaboration+). Finally, we will also report the latest results of the UV-to-radio SED fittings and studies on multiphase outflows for the X-WING AGNs and discuss the accretion and multi-scale ejection in AGNs.

Colton Hill（Chiba Univ.）
South Pole Science - Neutrino Oscillations and the IceCube Neutrino Detector Upgrade
Of all the Standard Model particles, neutrinos are the least well understood. While significant global progress has been made in characterising neutrino oscillations, several key questions remain unanswered: what are the masses of the neutrinos, and do neutrino oscillations truly follow the standard three-flavour model? The cubic-kilometre IceCube Neutrino Detector located at the geographic South Pole is capable of precision measurements of neutrino oscillation properties by observing neutrinos produced from particle interactions in the atmosphere across a broad range of energies (GeV-scale) and path lengths, often travelling through the Earth. To increase IceCube's sensitivity in the GeV-range, the IceCube Upgrade will involve deploying a dense array of high-sensitivity optical modules up to 3 km deep into the Antarctic glacier at the end of this year. One of these flagship modules, the "D-Egg", was developed and tested in Japan as part of an international effort for the Upgrade, and features a factor 2.8 per-device improvement in sensitivity over the current generation detectors. With enhanced direction reconstruction and a lower energy threshold, the Upgrade is expected to probe the neutrino mass ordering at the 3 sigma level within 5 years, and observe tau-neutrino appearance after just one year of data taking. As of January 2025, all 292 D-Eggs have arrived at the South Pole, with approx. 30% having already completed pre-deployment testing. This seminar with focus on the progress of the IceCube Upgrade, including the South Pole activities of the 2024/2025 Antarctic On-Ice Season, and share the latest sensitivities for the IceCube Upgrade ahead of data-taking later next year.

堀米 俊一（東北大学）
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Zhaoran Liu（東北大学）
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Mochammad Wardana（東北大学）
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佐藤 優理（東北大学）
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喜友名 正樹（東北大学）
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Nuo Chen（東北大学）
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津久井 崇史 (東北大学)
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