宇宙物理学研究系
Profile Information
- Affiliation
- Assistant Professor, Institute of Space and Astronautical Science, Department of Space Astronomy and Astrophysics, Japan Aerospace Exploration Agency
- Degree
- Ph. D(Jul, 2012, The University of Tokyo)
- Researcher number
- 20751176
- ORCID ID
https://orcid.org/0000-0002-5902-2672- J-GLOBAL ID
- 201901005927826680
- researchmap Member ID
- B000348585
宇宙素粒子物理学が専門です。現在はCMB偏光観測を行う衛星実験LiteBIRDの研究開発をしています。
宇宙初期の物理学、特にインフレーションやダークマターなどに興味があります。
Research Interests
6Research History
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Apr, 2020 - May, 2020
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Apr, 2017 - Mar, 2020
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Apr, 2014 - Mar, 2017
Papers
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Progress of Theoretical and Experimental Physics, 2024(2), Jan 22, 2024Abstract Understanding telescope pointing (i.e. line of sight) is important for observing the cosmic microwave background (CMB) and astronomical objects. The Moon is a candidate astronomical source for pointing calibration. Although the visible size of the Moon (30′) is larger than that of the planets, we can frequently observe the Moon once a month with a high signal-to-noise ratio. We developed a method for performing pointing calibration using observational data from the Moon. We considered the tilts of the telescope axes as well as the encoder and collimation offsets for pointing calibration. In addition, we evaluated the effects of the nonuniformity of the brightness temperature of the Moon, which is a dominant systematic error. As a result, we successfully achieved a pointing accuracy of 3.3′. This is one order of magnitude smaller than an angular resolution of 36′. This level of accuracy competes with past achievements in other ground-based CMB experiments using observational data from the planets.
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Journal of Astronomical Telescopes, Instruments, and Systems, 9(02), Apr 19, 2023
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Ground test results of the electromagnetic interference for the x-ray microcalorimeter onboard XRISMJournal of Astronomical Telescopes, Instruments, and Systems, 9(1) 18004, Jan 1, 2023Electromagnetic interference (EMI) for low-temperature detectors is a serious concern in many missions. We investigate the EMI caused by the spacecraft components to the x-ray microcalorimeter of the Resolve instrument onboard the x-ray imaging and spectroscopy mission, which is currently under development by an international collaboration and is planned to be launched in 2023. We focus on the EMI from (a) the low-frequency magnetic field generated by the magnetic torquers (MTQ) used for the spacecraft attitude control and (b) the radio-frequency (RF) electromagnetic field generated by the S and X band antennas used for communication between the spacecraft and the ground stations. We executed a series of ground tests both at the instrument and spacecraft levels using the flight-model hardware in 2021-2022 in a JAXA facility in Tsukuba. We also conducted electromagnetic simulations partially using the Fugaku high-performance computing facility. The MTQs were found to couple with the microcalorimeter, which we speculate through pick-ups of low-frequency magnetic field and further capacitive coupling. There is no evidence that the resultant energy resolution degradation is beyond the current allocation of noise budget. The RF communication system was found to leave no significant effect. We present the result of the tests and simulation in this article.
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Progress of Theoretical and Experimental Physics, 2023(4), Nov 21, 2022Abstract LiteBIRD the Lite (Light) satellite for the study of B-mode polarization and Inflation from cosmic background Radiation Detection, is a space mission for primordial cosmology and fundamental physics. The Japan Aerospace Exploration Agency (JAXA) selected LiteBIRD in May 2019 as a strategic large-class (L-class) mission, with an expected launch in the late 2020s using JAXA’s H3 rocket. LiteBIRD is planned to orbit the Sun-Earth Lagrangian point L2, where it will map the cosmic microwave background (CMB) polarization over the entire sky for three years, with three telescopes in 15 frequency bands between 34 and 448 GHz, to achieve an unprecedented total sensitivity of 2.2 μK-arcmin, with a typical angular resolution of 0.5○ at 100 GHz. The primary scientific objective of LiteBIRD is to search for the signal from cosmic inflation, either making a discovery or ruling out well-motivated inflationary models. The measurements of LiteBIRD will also provide us with insight into the quantum nature of gravity and other new physics beyond the standard models of particle physics and cosmology. We provide an overview of the LiteBIRD project, including scientific objectives, mission and system requirements, operation concept, spacecraft and payload module design, expected scientific outcomes, potential design extensions and synergies with other projects. Subject Index LiteBIRD cosmic inflation, cosmic microwave background, B-mode polarization, primordial gravitational waves, quantum gravity, space telescope
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Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI, 12190, Aug 31, 2022We verified a method of near-field antenna pattern measurement for a wide-field telescope with a bolometric detector array, based on a holographic phase-retrieval technique. A signal emitter scans the telescope aperture and a reference emitter, which is phase-locked to the signal, is located at a fixed position to allow a bolometric detector to receive the both. It generates a hologram on the focal plane as a function of the signal emitter location. Since the hologram is obtained in a receiving mode, we can use the telescope-equipped detector as it is. It is beneficial for the case where such detector is integrated with a feed antenna, which characterizes the telescope performance. The new method also has an advantage that we do not need the phase calibration of the reference emitter since it is constant. We experimentally demonstrated this method with a crossed-Dragone antenna whose field of view is 18 degrees x 9 degrees at 180 GHz for three representative detector positions in the focal plane. The antenna patterns were consistent with those measured by a vector near-field measurement at the level of -60 dB, which directly acquires both the phase and the amplitude of the electric field.
Misc.
49-
Ground test results of the electromagnetic interference for the x-ray microcalorimeter onboard XRISMSPACE TELESCOPES AND INSTRUMENTATION 2022: ULTRAVIOLET TO GAMMA RAY, 12181, Mar 2, 2023Electromagnetic interference (EMI) for low-temperature detectors is a serious concern in many missions. We investigate the EMI caused by the spacecraft components to the x-ray microcalorimeter of the Resolve instrument onboard the X-Ray Imaging and Spectroscopy Mission (XRISM), which is currently under development by an international collaboration and is planned to be launched in 2023. We focus on the EMI from (a) the low-frequency magnetic field generated by the magnetic torquers (MTQ) used for the spacecraft attitude control and (b) the radio-frequency (RF) electromagnetic field generated by the S and X band antennas used for communication between the spacecraft and the ground stations. We executed a series of ground tests both at the instrument and spacecraft levels using the flight-model hardware in 2021-2022 in a JAXA facility in Tsukuba. We also conducted electromagnetic simulations partially using the Fugaku high-performance computing facility. The MTQs were found to couple with the microcalorimeter, which we speculate through pick-ups of low-frequency magnetic field and further capacitive coupling. There is no evidence that the resultant energy resolution degradation is beyond the current allocation of noise budget. The RF communication system was found to leave no significant effect. We present the result of the tests and simulation in this article.
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日本物理学会講演概要集(CD-ROM), 78(1), 2023
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日本物理学会講演概要集(CD-ROM), 78(2), 2023
Major Presentations
79-
SPIE Astronomical Telescopes + Instrumentation, 2022, Jul, 2022
Research Projects
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科学研究費助成事業, 日本学術振興会, Apr, 2023 - Mar, 2028
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科学研究費助成事業 挑戦的研究(萌芽), 日本学術振興会, Jul, 2020 - Mar, 2023
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科学研究費助成事業 挑戦的研究(開拓), 日本学術振興会, Jun, 2019 - Mar, 2023
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Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Japan Society for the Promotion of Science, Jun, 2018 - Mar, 2023
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科学研究費助成事業 基盤研究(B), 日本学術振興会, Apr, 2019 - Mar, 2022
