Probing the face-on disc-corona system of the bare AGN Mrk 110 from UV to hard X-rays: A moderate changing-state AGN?

Porquet, D.; Hagen, S.; Grosso, N.; Lobban, A.; Reeves, J. N.; Braito, V.; Done, C.

Abstract

Context. The X-ray broadband spectra of the bare active galactic nucleus (AGN) Mrk 110, obtained by simultaneous XMM-Newton and NuSTAR observations performed in November 2019 and April 2020, are characterised by the presence of a prominent and absorption-free smooth soft X-ray excess, moderately broad O VII and Fe Kα emission lines, and a lack of a strong Compton hump. The disc-corona system is almost viewed face-on as inferred from the O VII accretion disc lines. While relativistic reflection as the sole emission is ruled out, a simplified combination of soft and hard Comptonisation (using COMPTT) from a warm and a hot corona, plus mild relativistic disc reflection (occuring at a few 10 s Rg) reproduces the data very well.

Aims. We aim to confirm the physical origin of the soft X-ray excess of Mrk 110 and to determine its disc-corona system properties from its energetics using two new sophisticated models: REXCOR and RELAGN, respectively.

Methods. We applied these models to the 0.3–79 keV X-ray broadband spectra and to the spectral energy distribution (SED) from UV to hard X-rays, respectively.

Results. At both epochs, the inferred high values of the warm-corona heating from the X-ray broadband spectral analysis using REXCOR confirm that the soft X-ray excess of Mrk 110 mainly originates from a warm corona rather than relativistic reflection. The intrinsic best-fit SED determined at both epochs using RELAGN show a high X-ray contribution relative to the UV and are very well reproduced by a warm and hot corona plus mild relativistic reflection. The outer radii of the hot and warm corona are located at a few 10 s and ∼100 Rg, respectively. Moreover, combining the inferred low Eddington ratio (approximatively a few percent) from this work, and previous multi-wavelength spectral and timing studies suggest that Mrk 110 could be classified as a moderate changing-state AGN.

Conclusions. Our analysis confirms the existence of a warm corona as a significant contribution to the soft X-ray excess and UV emission in Mrk 110, adding to growing evidence that AGN accretion deviates from standard disc theory. This strengthens the importance of long-term multi-wavelength monitoring on both single targets and large AGN surveys to reveal the real nature of the disc-corona system in AGNs.

Citation

Porquet, D., Hagen, S., Grosso, N., Lobban, A., Reeves, J. N., Braito, V., & Done, C. (2024). Probing the face-on disc-corona system of the bare AGN Mrk 110 from UV to hard X-rays: A moderate changing-state AGN?. Astronomy & Astrophysics, 681, Article A40. https://doi.org/10.1051/0004-6361/202347202

• Journal Article Type: Article
• Acceptance Date: Oct 20, 2023
• Online Publication Date: Jan 5, 2024
• Publication Date: 2024-01
• Deposit Date: Jan 10, 2024
• Publicly Available Date: Jan 12, 2024
• Journal: Astronomy & Astrophysics
• Print ISSN: 0004-6361
• Electronic ISSN: 1432-0746
• Publisher: EDP Sciences
• Peer Reviewed: Peer Reviewed
• Volume: 681
• Article Number: A40
• DOI: https://doi.org/10.1051/0004-6361/202347202
• Public URL: https://durham-repository.worktribe.com/output/2118323