Unveiling slim accretion disc in AGN through X-ray and Infrared observations

Abstract

In this work, which is a continuation of Castelló-Mor et al. (2016), we present new X-ray and infrared (IR) data for a sample of active galactic nuclei (AGN) covering a wide range in Eddington ratio over a small luminosity range. In particular, we rigorously explore the dependence of the optical-to-X-ray spectral index ${\alpha }_{OX}$ and the IR-to-optical spectral index on the dimensionless accretion rate, $\dot{\mathcal{M}}=\dot{m}/\eta$ where $\dot{m}=L_{AGN}/L_{Edd}$ and $\eta$ is the mass-to-radiation conversion efficiency, in low and high accretion rate sources. We find that the SED of the faster accreting sources are surprisingly similar to those from the comparison sample of sources with lower accretion rate. In particular: i) the optical-to-UV AGN SED of slow and fast accreting AGN can be fitted with thin AD models. ii) The value of ${\alpha }_{OX}$ is very similar in slow and fast accreting systems up to a dimensionless accretion rate ${\dot{\mathcal{M}}}_c\sim$10. We only find a correlation between ${\alpha }_{OX}$ and $\dot{\mathcal{M}}$ for sources with $\dot{\mathcal{M}}>{\dot{\mathcal{M}}}_c$. In such cases, the faster accreting sources appear to have systematically larger ${\alpha }_{OX}$ values. iii) We also find that the torus in the faster accreting systems seems to be less efficient in reprocessing the primary AGN radiation having lower IR-to-optical spectral slopes. These findings, failing to recover the predicted differences between the SEDs of slim and thin ADs within the observed spectral window, suggest that additional physical processes or very special geometry act to reduce the extreme UV radiation in fast accreting AGN. This may be related to photon trapping, strong winds, and perhaps other yet unknown physical processes.

arXiv commentAccepted for publication on MNRAS, 14 pages, 7 figures

References in corpus (21)

• Reverberation Measurements for 17 Quasars and the Size-Mass-Luminosity Relations in Active Galactic Nuclei
• The Low-Luminosity End of the Radius-Luminosity Relationship for Active Galactic Nuclei
• The Radius-Luminosity Relationship for Active Galactic Nuclei: The Effect of Host-Galaxy Starlight on Luminosity Measurements II. The Full Sample of Reverberation-Mapped AGNs
• A Global Three Dimensional Radiation Magneto-hydrodynamic Simulation of Super-Eddington Accretion Disks
• Simultaneous X-ray/optical/UV snapshots of active galactic nuclei from XMM-Newton: spectral energy distributions for the reverberation mapped sample
• The Simultaneous Optical-to-X-ray Spectral Energy Distribution of Soft X-ray Selected AGN observed by Swift
• Slim Disk Model for Soft X-Ray Excess and Variability of Narrow-Line Seyfert 1 Galaxies
• The black hole mass - stellar velocity dispersion relation of narrow-line Seyfert 1 galaxies
• Supermassive black holes with high accretion rates in active galactic nuclei: I. First results from a new reverberation mapping campaign
• Three-dimensional simulations of super-critical black hole accretion disks --- luminosities, photon trapping and variability
• Hot Graphite Dust and the Infrared Spectral Energy Distribution of Active Galactic Nuclei
• Continuum and Emission Line Strength Relations for a large Active Galactic Nuclei Sample
• Super-Eddington accretion rates in Narrow Line Seyfert 1 galaxies
• Optical--to--X-ray emission in low-absorption AGN: Results from the Swift-BAT 9 month catalogue
• Super-Eddington accreting massive black holes as long-lived cosmological standards
• X-ray properties of the Northern Galactic Cap AGNs in the 58-month Swift-BAT catalog
• The Effects of Disc Winds on the Spectrum and Black Hole Growth Rate of Active Galactic Nuclei
• Studying the relationship between X-ray emission and accretion in AGNs using the XMM-Newton Bright Serendipitous Survey
• Super- and sub-Eddington accreting massive black holes: A comparison of slim and thin accretion discs through study of the spectral energy distribution
• A comparison of hard X-ray photon indices and iron \ka emission lines in X-ray luminous narrow- and broad-line Seyfert 1 galaxies
• New Method for Exploring Super-Eddington AGNs by Near-infrared Observations

Cited by in corpus (8)

• The Lick AGN Monitoring Project 2011: Dynamical Modeling of the Broad-Line Region
• Accretion Disk Sizes from Continuum Reverberation Mapping of AGN Selected from the ZTF Survey
• The Extreme Super-Eddington NLS1 RX J0134.2-4258 -- II. A Weak-Line Seyfert Linking to the Weak-Line Quasar
• Connecting Low- and High-Redshift Weak Emission-Line Quasars via HST Spectroscopy of Ly$\alpha$ Emission
• No evidence for an Eddington-ratio dependence of X-ray weakness in BALQSOs
• The first X-ray look at SMSS J114447.77-430859.3: the most luminous quasar in the last 9 Gyr
• Radio Scrutiny of the X-ray-Weak Tail of Low-Mass Active Galactic Nuclei: A Novel Signature of High-Eddington Accretion?
• Slim accretion disks: theory and observational consequences