2026-10-06 北里大学
図1 代表的な従来の撮像法であるコンプトンカメラではガンマ線の方向が円環となるため、点線源の撮像も大きく広がる。（Y. Mizumura, et al., J. Instrum., 9, C05045より引用）
＜関連情報＞
- https://www.kitasato.ac.jp/jp/news/20261006-01.html
- https://journals.aps.org/prd/abstract/10.1103/h89s-4p7q
- https://www.kitasato.ac.jp/jp/albums/abm.php?f=abm00050044.pdf
電子追跡コンプトンカメラを用いたサブMeVガンマ線帯での銀河中心の観測 Observation of the Galactic Center in the sub-MeV gamma-ray band with an electron-tracking Compton camera
Tomonori Ikeda,Toru TanimoriAtsushi Takada, Taito Takemura, Kei Yoshikawa, Yuta Nakamura, Ken Onozaka, and Mitsuru Abe,Yoshitaka Mizumura
Physical Review D Published: 11 August, 2026
DOI: https://doi.org/10.1103/h89s-4p7q
Abstract
We report the direct detection of gamma-ray emission from the Galactic Center in the 150–600 keV band using the electron-tracking Compton camera (ETCC), which has a wide field of view of 3.1 sr. This represents the first application of this linear, imaging-spectroscopy method to observations of the Galactic Center. Measurements in a one-day flight over Australia yielded significant gamma-ray detection in the light curve and revealed a 7.9σ excess over the background in the image map from the Galactic Center region. These results, obtained through a simple and unambiguous analysis, demonstrate the high reliability and sensitivity of the ETCC and establish its potential for future high-precision MeV gamma-ray observations. The measured intensity and spatial distribution were tested against three emission models: a single pointlike source, a multicomponent structure, and a symmetric two-dimensional Gaussian. All three were found to be statistically consistent with the data. The positronium-related flux provided by the multicomponent model is (3.2 ±1.4) ×10−2 photons cm−2 s−1, consistent with the value reported by INTEGRAL within 1σ. These results establish the potential of the ETCC for future high-precision MeV gamma-ray surveys.
