The Peculiar Variable X-Ray Spectrum of the Active Galactic Nucleus PKS 2005-489

Chase O, McBride F, Gokus A, Lucchini M, Zhang H, Ojha R, Fox DB (2023)

Publication Type: Journal article

Publication year: 2023

Journal

Astrophysical Journal American Astronomical Society

Book Volume: 948

Article Number: 2

Journal Issue: 1

DOI: 10.3847/1538-4357/acc575

Abstract

PKS 2005−489 is a well-known, bright southern BL Lac object that has been detected up to TeV energies. In a low-flux state it exhibits the expected multiwavelength double-peaked spectrum in the radio−γ-ray band. The high-flux state shows extreme flux variations in the X-ray band with a hardening as well as a peculiar curved feature in the spectrum. Thus far, PKS 2005−489 is the only source to exhibit such a feature. To study the X-ray variability further, we obtained the first hard X-ray spectrum of the source with the Nuclear Spectroscopic Telescope Array. We compare quasi-simultaneous radio, optical, UV, soft and hard X-ray, and γ-ray data of PKS 2005−489 to archival data in order to study its broadband behavior. We find a very consistent quiet state in the spectral energy distribution, with little variation in spectral shape or flux between the 2012 and 2020 data. A possible explanation for the peculiar X-ray spectrum in the flaring state is an additional component in the jet, possibly accelerated via magnetic reconnection, that is not co-spatial to the low-flux state emission region.

Involved external institutions

Pennsylvania State University (Penn State) US United States (USA) (US) Bowdoin College US United States (USA) (US) Washington University US United States (USA) (US) Massachusetts Institute of Technology (MIT) US United States (USA) (US) National Aeronautics and Space Administration (NASA) US United States (USA) (US)

How to cite

APA:

Chase, O., McBride, F., Gokus, A., Lucchini, M., Zhang, H., Ojha, R., & Fox, D.B. (2023). The Peculiar Variable X-Ray Spectrum of the Active Galactic Nucleus PKS 2005-489. Astrophysical Journal, 948(1). https://doi.org/10.3847/1538-4357/acc575

MLA:

Chase, Owen, et al. "The Peculiar Variable X-Ray Spectrum of the Active Galactic Nucleus PKS 2005-489." Astrophysical Journal 948.1 (2023).

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