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arXiv · 2205.07438

Hard X-ray emission in Centaurus A

B. Rani·S. A. Mundo·R. Mushotzky·A. Y. Lien·M. A. Gurwell·J. Y. Kim
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Abstract

We used 13 years of Swift/BAT observations to probe the nature and origin of hard X-ray (14-195 KeV) emission in Centaurus A. Since the beginning of the Swift operation in 2004, significant X-ray variability in the 14-195 KeV band is detected, with mild changes in the source spectrum. Spectral variations became more eminent after 2013, following a softer-when-brighter trend. Using the power spectral density method, we found that the observed hard X-ray photon flux variations are consistent with a red-noise process of slope, $-1.3$ with no evidence for a break in the PSD. We found a significant correlation between hard X-ray and 230 GHz radio flux variations, with no time delay longer than 30 days. The temporal and spectral analysis rules out the ADAF (advection-dominated accretion flow) model, and confirms that the hard X-ray emission is produced in the inner regions of the radio jet.

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B. Rani, S. A. Mundo, R. Mushotzky, A. Y. Lien, M. A. Gurwell, J. Y. Kim. 2022-05-16. Hard X-ray emission in Centaurus A. https://doi.org/10.3847/1538-4357/ac6fd4

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