Related papers: Diffuse emission in microlensed quasars and its im…
Results from a few decades of reverberation mapping (RM) studies have revealed a correlation between the radius of the broad-line emitting region (BLR) and the continuum luminosity of active galactic nuclei. This "radius-luminosity"…
We show how analysis of a quasar high-magnification microlensing event may be used to construct a map of the frequency-dependent surface brightness of the quasar accretion disk. The same procedure also allows determination of the disk…
The quadruply lensed quasar HE0435-1223 shows a clear microlensing effect that affects differently the blue and red wings of the H$\alpha$ line profile in its image D. To interpret these observations, and constrain the broad emission line…
Recent observations have provided strong evidence for the presence of an Electron Scattering Region (ESR) within the central regions of AGNs. This is responsible for reprocessing emission from the accretion disk into polarised radiation.…
This paper sets out to measure the timescale of quasar variability with a view to new understanding of the size of accretion discs in active galactic nuclei. Previous attempts to measure such timescales have been based on sparsely sampled…
We study the time lags between the continuum emission of quasars at different wavelengths, based on more than four years of multi-band ($g$, $r$, $i$, $z$) light-curves in the Pan-STARRS Medium Deep Fields. As photons from different bands…
We consider the influence of microlensing on different spectral bands of lensed QSOs. We assumed that the emitting X-ray, UV and optical regions are different in size, but that the continuum emission in these spectral bands is originating…
Quasars accretion models predict a broad range of optical and ultraviolet properties that depend primarily on black hole mass and accretion rate. Yet, most optically selected luminous quasars display strikingly similar continuum spectra. We…
We present monitoring observations of quasar microlensing in the quadruple quasar HE0435-1223. The microlensing-induced light curves of the quasar images are chromatic, i.e. they depend on the applied filter band. Comparison with…
(abridged) We have spectrophotometrically monitored a well-defined sample of 28 Palomar-Green quasars in order to obtain measurements of their BLRs and to investigate the relationships between quasar luminosity, central black hole mass, and…
We study three high magnification microlensing events, generally recognized as probable caustic crossings, in the optical light curves of the multiply imaged quasar Q 2237+0305. We model the light curve of each event as the convolution of a…
The determination of the size and geometry of the broad line region (BLR) in active galactic nuclei is one of the major ingredients for determining the mass of the accreting black hole. This can be done by determining the delay between the…
We discuss the effects of microlensing on the broad emission lines (BELs) of QSOs in the light of recent determinations of the size of the broad line region (BLR) and its scaling with QSO luminosity. Microlensing by star-sized objects can…
Several macrolensed systems exhibit photometric variability consistent with microlensing due to objects of stellar mass located in the lens. The degree of microlensing amplification is dependent upon the size of the source, with smaller…
The influence of microlensing in the profiles of the emission lines generated in a biconical geometry is discussed. Microlensing amplification in this anisotropic model is not directly related to the bicone's intrinsic size but depends on…
We analyzed the CIV line profile distortions due to microlensing in two quasars, J1339 and J1138. J1339 shows a strong, asymmetric line profile deformation, while J1138 shows a more modest, symmetric deformation. To probe the CIV broad line…
A crucial difficulty in understanding the nature of the putative accretion disk in AGNs is that some of its key intrinsic spectral signatures cannot be observed directly. The strong emissions from the broad-line region (BLR) and the…
With the detection of black hole mergers by the LIGO gravitational wave telescope, there has been increasing interest in the possibility that dark matter may be in the form of solar mass primordial black holes. One of the predictions…
Powered by supermassive black holes at their centers, quasars are among the most luminous objects in the Universe, serving as important probes of cosmic history and galaxy evolution. The size of the accretion disc surrounding the black hole…
The microlensing signal in the light curves of gravitationally lensed quasars can shed light on the dark matter (DM) composition in their lensing galaxies. Here, we investigate a sample of six lensed quasars from the most recent and best…