Origins of the UV/X-ray relation in Arakelian 120

• DOI: 10.1093/mnras/stac3809
• Publication Date: 2023-02-02T23:03:26Z
• Authors: R D Mahmoud; C Done; D Porquet; A Lobban
• Keywords: Corona (planetary geology); Spectral energy distribution; Accretion disc

ABSTRACT We explore the accretion geometry in Arakelian 120 using intensive UV and X-ray monitoring from Swift. The hard X-rays (1–10 keV) show large amplitude, fast (few-day) variability, so we expect reverberation disc to produce variability varying illumination. model spectral energy distribution (SED) including an outer standard (optical), intermediate warm-Comptonization region (UV soft X-ray), a hot corona (hard X-rays). Unlike lower Eddington fraction AGN (NGC 4151 NGC 5548 at L/LEdd ∼ 0.02 0.03, respectively), SED of Akn (L 0.05LEdd) is dominated by UV, restricting impact reverberating energetics alone. Illumination with height ∼10 Rg produces minimal variability. Increasing coronal scale ∼100 improves match observed amplitude as subtends larger solid angle, but results too much data. (connected model) are more variable than hard, again contain smoother seen UV. Results on have emphasized contribution scales (the broad-line region), induces lags similar time-scales smoothing, producing delay compatible conclude that majority therefore intrinsic, connected mass-accretion rate fluctuations region.