Related papers: Sustaining a Warm Corona in Active Galactic Nuclei…
A warm corona at the surface of an accretion disc has been proposed as a potential location for producing the soft excess commonly observed in the X-ray spectra of active galactic nuclei (AGNs). In order to fit the observed data the gas…
In the X-ray spectra of AGNs, a noticeable excess of soft X-rays is typically detected beyond the extrapolation of the power-law trend observed between 2-10 keV. In the scenario of warm Comptonization, observations propose a warm corona…
The soft X-ray excess in the spectra of active galactic nuclei is characterized by similar electron temperatures of 0.1 -- 0.3 keV and similar photon indices around 2.2 -- 3, if fitted with inverse Comptonization. It remains a puzzle why…
In the past years, several observations of AGN and X-ray binaries have suggested the existence of a warm T around 0.5-1 keV and optically thick, \tau ~ 10-20, corona covering the inner parts of the accretion disk. These properties are…
The X-ray spectra of many active galactic nuclei (AGN) show a soft X-ray excess below 1-2 keV on top of the extrapolated high- energy power law. The origin of this component is uncertain. It could be a signature of relativistically blurred,…
The soft excess in active galactic nuclei (AGNs) may arise through a combination of relativistic reflection and the effects of a warm corona at the surface of the accretion disc. Detailed examination of the soft excess can therefore…
Context. Warm corona is a possible explanation for Soft X-ray Excess in Active Galactic Nuclei (AGN). This paper contains self consistent modeling of both: accretion disk with optically thick corona, where the gas is heated by…
The X-ray spectra of active galactic nuclei (AGNs) often exhibit an excess of emission above the primary power-law at energies <~ $2$ keV. Two models for the origin of this `soft excess' are ionized relativistic reflection from the inner…
Context. AGNs are strong X-ray emitters shaped by disk-corona interactions. The soft excess (0.5-2.0 keV) reveals key information about the "warm corona" bridging the disk and hot corona. Yet, how this feature evolves with accretion…
A soft X-ray excess above the 2-10 keV power law extrapolation is generally observed in AGN X-ray spectra. Presently there are two competitive models to explain it: blurred ionized reflection and warm Comptonisation. In the latter case,…
A new mechanism to form a magnetic pressure supported, high temperature corona above the photosphere of an accretion disk is explored using three dimensional radiation magneto-hydrodynamic (MHD) simulations. The thermal properties of the…
This paper is devoted to self-consistent modeling of the magnetically supported accretion disk with optically thick warm corona based on first principles. In our model, we consider the gas heating by magneto-rotational instability (MRI)…
We present the properties of accretion disk corona (ADC) models, where the radiation field, the temperature, and the total opacity of the corona are determined self-consistently. We use a non-linear Monte Carlo code to perform the…
The heating mechanism of a corona above an accretion disk in active galactic nuclei (AGNs) is still unknown. One possible mechanism is magnetic reconnection heating requiring energy equipartition between magnetic energy and gas energy in…
It is believed that the hard X-ray emission in the luminous active galactic nuclei (AGNs) is from the hot corona above the cool accretion disk. However, the formation of the corona is still debated. Liu et al. investigated the spectrum of…
The X-ray emission from bright active galactic nuclei (AGNs) is believed to originate in a hot corona lying above a cold, geometrically thin accretion disk. A highly concentrated corona located within $\sim10$ gravitational radii above the…
A long-standing question in active galactic nucleus (AGN) research is how the corona is heated up to produce X-ray radiation much stronger than that arising from the viscous heating within the corona. In this paper, we carry out detailed…
We investigate the accretion process in high-luminosity AGNs (HLAGNs) in the scenario of the disk evaporation model. Based on this model, the thin disk can extend down to the innermost stable circular orbit (ISCO) at accretion rates higher…
We study an accretion disc with a hot continuous corona. We assume that the corona itself accretes and therefore it is powered directly by the release of the gravitational energy and cooled by radiative interaction with the disc. We…
This work attempts to provide a new interpretation for the hot corona in active galactic nuclei (AGNs). A thin parabolic magnetic reconnection layer, anchored at the innermost disk and extending along the boundary of the magnetic tower for…