Correlation Between Optical and X-ray Break Frequencies in Power Spectra of Active Galactic Nuclei
| Autor: | Yuk, Heechan, Dai, Xinyu, Jayasinghe, T., Vallely, Patrick J., Kochanek, Christopher S., Shappee, Benjamin J., Stanek, K. Z. |
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| Jazyk: | angličtina |
| Rok vydání: | 2023 |
| Předmět: | |
| Popis: | We analyze the optical power spectral density (PSD) for 22 active galactic nuclei (AGN) with measured X-ray PSDs using light curves from the All-Sky Automated Survey for SuperNovae (ASAS-SN) and the Transiting Exoplanet Survey Satellite (TESS). The joint optical PSD is measured over up to six orders of magnitude in frequency space from timescales of minutes to a decade. We fit either a damped random walk (DRW) or a broken power law model to constrain the PSD model and break frequency. For the broken power-law fits to the joint PSDs, we find a high-frequency timescale which is proportional to both the X-ray timescales and the black hole masses, but the optical timescale is 2.7 dex longer. Assuming the optical and X-ray breaks are related by a physical process, such as reprocessing of X-ray emission, the break frequency difference interpreted as a light crossing time is consistent with the expected size difference between the optical and X-ray emission regions. On timescales of months to a decade, we also measured a correlation between the low-frequency optical break timescales and the X-ray break timescales, but with a much shallower slope. The DRW model provides acceptable fits and we generally confirm previously reported correlations between the DRW timescales and the black hole mass. 20 pages, 16 figures, submitted to ApJ |
| Databáze: | OpenAIRE |
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