Related papers: High-density disc reflection spectroscopy of low-m…
We have conducted a systematic search of low-mass black holes (BHs) in active galactic nuclei (AGNs) with broad Halpha emission lines, aiming at building a homogeneous sample that is more complete than previous ones for fainter, less highly…
High-redshift ($z>2$) blazars, with relativistic jets aligned toward us, probe the most powerful end of the active galactic nuclei (AGN) population. We aim at determining the black hole masses and mass accretion rates of high-$z$ blazars in…
Models of jet production in black hole systems suggest that the properties of the accretion disk - such as its mass accretion rate, inner radius, and emergent magnetic field - should drive and modulate the production of relativistic jets.…
We study the structure of accretion disks around supermassive black holes in the radial range $30\sim 100$ gravitational radii, using a three dimensional radiation magneto-hydrodynamic simulation. For typical conditions in this region of…
Some ultraluminous X-ray sources in nearby galaxies show soft components resembling thermal disc emission. Calculations based on blackbody emission then indicate that the accreting black holes at the centres of these discs have masses of…
We discuss constraints on the physics of the inner accretion disk, as well as the properties of the black hole itself, that can be derived by a detailed examination of the relativistically broadened spectral features (especially the…
We present a new scenario to explain the soft X-ray excess in Active Galactic Nucleus. The magnetic reconnection could happen in a thin layer on the surface of accretion disk. Electrons are accelerated by shock wave and turbulence triggered…
Black-hole accretion systems are known to possess several distinct modes (or spectral states), such as low/hard state, high/soft state, and so on. Since the dynamics of the corresponding flows is distinct, theoretical models were separately…
We implement a standard thin disk model with the outer disk radius ($R_{\rm out}$) as a free parameter, integrating it into standard X-ray fitting package to enable self-consistent and simultaneous fitting of X-ray spectra and…
We present the identification and analysis of an unbiased sample of AGN that lie within the local galaxy population. Using the MPA-JHU catalogue (based on SDSS DR8) and 3XMM DR7 we define a parent sample of 25,949 local galaxies ($z \leq…
Along the last ten years, a general relativistic method has been developed to generate analytical expressions for the black hole (BH) parameters in terms of observables, namely the frequency shift of photons emitted by orbiting test…
Accretion disks and coronae around massive black holes have been studied extensively, and they are known to be coupled. Over a period of 30 years, however, the X-ray (coronal) flux of Mrk 817 increased by a factor of 40 while its UV (disk)…
We use a coupled model of the formation and evolution of galaxies and black holes (BH) to study the evolution of active galactic nuclei (AGN) in a cold dark matter universe. The model predicts the BH mass, spin and mass accretion history.…
The radiative and jet efficiencies of thin magnetized accretion disks around black holes (BHs) are affected by BH spin and the presence of a magnetic field that, when strong, could lead to large deviations from Novikov-Thorne (NT) thin disk…
Luminous accretion disks around black holes are expected to have densities of $\sim 10^{15-22}\,$cm$^{-3}$, which are high enough such that plasma physics effects become important. Many of these effects have been traditionally neglected in…
With respect to the $\rm H\beta$ full width at half-maximum ($\rm FWHM_{H\beta}$), the broad $\rm H\beta$ line dispersion ($\sigma_{\rm H\beta}$) was preferred as a velocity tracer to calculate the single-epoch supermassive black hole mass…
If the atmospheric density $\rho_{atm}$ in the accretion disk of an active galactic nucleus (AGN) is sufficiently low, scattering in the atmosphere can produce a non-blackbody emergent spectrum. For a given bolometric luminosity, at…
The X-ray properties of Active Galactic Nuclei (AGNs) depend on their underlying physical parameters, particularly the accretion rate. We identified eight reverberation-mapped AGNs with some of the largest known accretion rates without…
We construct evolutionary models of the populations of AGN and supermassive black holes, in which the black hole mass function grows at the rate implied by the observed luminosity function, given assumptions about the radiative efficiency…
The JWST has enabled the discovery of Active Galactic Nuclei at high redshifts. The intrinsic UV spectrum of GN-z11 at redshift z=10.6 has a spectral slope compatible with a standard accretion disc. By fitting a disc model to its spectrum,…