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; Ehud Behar

doi:10.3847/1538-4357/ad73a1

The Astrophysical Journal (Jan 2024)

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,
Ehud Behar

Affiliations

David Bogensberger: ORCiD; Department of Astronomy, The University of Michigan , 1085 South University Avenue, Ann Arbor, Michigan, 48103, USA
Jon M Miller: ORCiD; Department of Astronomy, The University of Michigan , 1085 South University Avenue, Ann Arbor, Michigan, 48103, USA
Richard Mushotzky: Department of Astronomy, University of Maryland , College Park, MD 20742, USA
W. N. Brandt: ORCiD; Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University , University Park, PA 16802, USA; Institute for Gravitation and the Cosmos, The Pennsylvania State University , University Park, PA 16802, USA; Department of Physics, 104 Davey Laboratory, The Pennsylvania State University , University Park, PA 16802, USA
Elias Kammoun: ORCiD; IRAP, Université de Toulouse , CNRS, UPS, CNES, 9, Avenue du Colonel Roche, BP 44346, F-31028, Toulouse Cedex 4, France; INAF—Osservatorio Astrofisico di Arcetri , Largo Enrico Fermi 5, I-50125 Firenze, Italy; Dipartimento di Matematica e Fisica, Università Roma Tre , via della Vasca Navale 84, I-00146 Rome, Italy
Abderahmen Zoghbi: ORCiD; Department of Astronomy, University of Maryland , College Park, MD 20742, USA; HEASARC , Code 6601, NASA/GSFC, Greenbelt, MD 20771, USA; CRESST II, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA
Ehud Behar: ORCiD; Faculty of Physics, Technion—Israel Institute of Technology , Haifa, 3200003, Israel

DOI: https://doi.org/10.3847/1538-4357/ad73a1
Journal volume & issue: Vol. 974, no. 2
p. 307

Abstract

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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 ± 0.4 c . This constrains the inclination of the jet to be i 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 ± 0.1 c , 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.

Published in The Astrophysical Journal

ISSN: 1538-4357 (Online)
Publisher: IOP Publishing
Country of publisher: United Kingdom
LCC subjects: Science: Astronomy: Astrophysics
Website: https://iopscience.iop.org/journal/0004-637X

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