2024-10-28 ミシガン大学
<関連情報>
- https://news.umich.edu/seeing-a-black-holes-jet-in-a-new-light/
- https://iopscience.iop.org/article/10.3847/1538-4357/ad73a1
ケンタウルス座AのX線ジェットにおける超光速固有運動 Superluminal Proper Motion in the X-Ray Jet of Centaurus A
David Bogensberger, Jon M Miller, Richard Mushotzky, W. N. Brandt, Elias Kammoun, Abderahmen Zoghbi,,, and Ehud Behar
The Astrophysical Journal Published: 2024 October 18
DOI:10.3847/1538-4357/ad73a1
Abstract
The structure of the jet in Cen A is likely better revealed in X-rays than in the radio band, which is usually used to investigate jet proper motions. In this paper, we analyze Chandra Advanced CCD Imaging Spectrometer observations of Cen A from 2000 to 2022 and develop an algorithm for systematically fitting the proper motions of its X-ray jet knots. Most of the knots had an apparent proper motion below the detection limit. However, one knot at a transverse distance of 520 pc had an apparent superluminal proper motion of 2.7 ± 0.4c. This constrains the inclination of the jet to be i < 41° ± 6° and the velocity of this knot to be β > 0.94 ± 0.02. This agrees well with the inclination measured in the inner jet by the Event Horizon Telescope but contradicts previous estimates based on jet and counterjet brightness. It also disagrees with the proper motion of the corresponding radio knot, of 0.8 ± 0.1c, which further indicates that the X-ray and radio bands trace distinct structures in the jet. There are four prominent X-ray jet knots closer to the nucleus, but only one of these is inconsistent with being stationary. A few jet knots also have a significant proper-motion component in the nonradial direction. This component is typically larger closer to the center of the jet. We also detect brightness and morphology variations at a transverse distance of 100 pc from the nucleus.