LHAASOが「アクイラ・ブースター」を発見、パルサー風星雲の粒子加速理論限界に挑戦(LHAASO Discovers ‘Aquila Booster,’ Challenging Theoretical Limits of Particle Acceleration in Pulsar Wind Nebulae)

2026-04-24 中国科学院(CAS)

中国の高エネルギー観測施設LHAASOは、わし座のパルサーPSR J1849-0001に伴うパルサー風星雲からPeV級ガンマ線を検出し、新たな超高エネルギー加速天体「Aquila Booster」を発見した。この天体は粒子加速効率が理論上限の少なくとも27%に達し、従来の代表例であるカニ星雲を上回る可能性が示された。さらにガンマ線スペクトルは2PeVまで伸び、低いスピンダウン光度にもかかわらず非常に高い放射効率を示した。従来モデルでは終端衝撃波での加速が想定されていたが、本結果では効率が理論的限界を超える矛盾が生じ、新たな加速機構の必要性が示唆された。本研究はパルサー風星雲の粒子加速理論の再検討を促す重要な成果である。

LHAASOが「アクイラ・ブースター」を発見、パルサー風星雲の粒子加速理論限界に挑戦(LHAASO Discovers ‘Aquila Booster,’ Challenging Theoretical Limits of Particle Acceleration in Pulsar Wind Nebulae)
Artist’s impression of the Aquila Booster and LHAASO. (Image by LHAASO Collaboration)

<関連情報>

パルサーPSR J1849−0001によって駆動される極限粒子加速器 An extreme particle accelerator powered by pulsar PSR J1849−0001

The LHAASO Collaboration
Nature Astronomy  Published:13 April 2026
DOI:https://doi.org/10.1038/s41550-026-02839-0

Abstract

Pulsar wind nebulae (PWNe) are bubbles of relativistic particles, powered by the rotational energy loss of the central pulsars. The Crab Nebula, powered by the Milky Way’s most energetic pulsar, was discovered by the Large High Altitude Air Shower Observatory (LHAASO) as a PeV gamma-ray emitter, thereby establishing it as an extreme particle accelerator along with multiwavelength observations. Here we report LHAASO’s detection of a point-like ultrahigh-energy (UHE, photon energy E > 100 TeV) gamma-ray source associated with the PWN powered by PSR J1849-0001, a pulsar of spindown power 50 times lower than the Crab pulsar. The measured gamma-ray spectrum extends to PeV energies following a power-law distribution, with the PeV luminosity a few times higher than that of the Crab Nebula. Combined X-ray observations constrain the average magnetic field within the source to about 3 μG, and reveal an extreme particle acceleration efficiency approaching or even exceeding unity in the PWN, which we refer to as the ‘Aquila Booster’. The result challenges the particle acceleration theory in PWN and implies non-ideal magnetohydrodynamics (MHD) conditions within the accelerator, potentially involving magnetic reconnection upstream of the termination shock.

1701物理及び化学
ad
ad
Follow
ad
タイトルとURLをコピーしました