チャンドラ望遠鏡、銀河構造の亀裂原因を解明(NASA’s Chandra Diagnoses Cause of Fracture in Galactic “Bone”)

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2025-05-01 NASA

チャンドラ望遠鏡、銀河構造の亀裂原因を解明(NASA’s Chandra Diagnoses Cause of Fracture in Galactic “Bone”)
X-ray: NASA/CXC/Northwestern Univ./F. Yusef-Zadeh et al; Radio: NRF/SARAO/MeerKat; Image Processing: NASA/CXC/SAO/N. Wolk

NASAのチャンドラX線望遠鏡と南アフリカのMeerKAT電波望遠鏡の観測により、天の川銀河中心にある「銀河の骨」構造G359.13(通称「スネーク」)に亀裂があることが判明した。この原因は、超新星爆発後に生じた高速で移動する中性子星(パルサー)が構造に衝突したためと考えられている。パルサーは時速160万〜320万キロメートルで移動し、衝突によってG359.13の磁場を歪め、電波信号にも影響を与えた。G359.13は約230光年の長さを持ち、地球から約2万6千光年離れている。この研究成果は学術誌『Monthly Notices of the Royal Astronomical Society』に掲載された。

<関連情報>

G359.13142-0.20005:銀河中心蛇(G359.1-0.2)に走るX線と対をなす急峻なスペクトルの電波パルサー候補 G359.13142-0.20005: a steep spectrum radio pulsar candidate with an X-ray counterpart running into the Galactic Centre Snake (G359.1-0.2)

F Yusef-Zadeh , Jun-Hui Zhao , R Arendt , M Wardle , C O Heinke , M Royster , C Lang , J Michail
Monthly Notices of the Royal Astronomical Society  Published:23 February 2024
DOI:https://doi.org/10.1093/mnras/stae549

ABSTRACT

The Snake is a remarkable Galactic Centre radio filament with a morphology characterized by two kinks along its ∼20 arcmin extent. The major and minor kinks are located where the filament is most distorted from a linear magnetized structure running perpendicular to the Galactic plane. We present Chandra, VLA, and MeerKAT data and report the detection of an X-ray and radio source at the location of the major kink. High-resolution radio images of the major kink reveal a compact source with a steep spectrum with spectral index α ∼ −2.7 surrounded by extended emission. The radio luminosity and steep spectrum of the compact source are consistent with a pulsar. We also show flattening of the spectrum and enhanced synchrotron emissivity away from the position of the major kink along the Snake, which suggests injection of relativistic particles along the Snake. We argue that the major kink is created by a fast-moving (∼500–1000 km s−1) object punching into the Snake, distorting its magnetic structure, and producing X-ray emission. X-ray emission pinpoints an active acceleration site where the interaction is taking place. A secondary kink is argued to be induced by the impact of the high-velocity object producing the major kink.

1701物理及び化学
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