Related papers: Interpreting the Variability of Double-Peaked Emis…
Broad emission line regions (BLRs) lying into central accretion disks has been widely accepted to explain the unique double-peaked broad emission lines in Active Galactic Nuclei (double-peaked BLAGNs). Here, accepted the accretion disk…
We present theoretical models of X-ray variability attributable to orbital signatures from an accretion disk including emission region size, quasi-periodic oscillations (QPOs) and its quality factor $Q$, and the emergence of a break…
We use the Athena hydrodynamics code to model propagating two-dimensional relativistic jets as approximations to the growth of radio-loud active galactic nuclei for various input jet velocities and jet-to-ambient matter density ratios.…
Finding low-mass planets around solar-type stars requires to understand the physical variability of the host star, which greatly exceeds the planet-induced radial-velocity modulation. Different solar photospheric absorption lines have…
We present optical longslit observations of the complete sample of 71 Type 2 active galactic nuclei (AGNs) with double-peaked narrow emission lines at $z < 0.1$ in the Sloan Digital Sky Survey. Double-peaked emission lines are produced by a…
[Abridged] Optically thick, geometrically thin accretion disks around supermassive black holes are thought to contribute to broad-line emission in type-1 active galactic nuclei (AGN). However, observed emission line profiles most often…
The double-peaked broad emission lines are usually thought to be linked to accretion disks, however, the local viscous heating in the line-emitting disk portion is usually insufficient for the observed double-peaked broad-line luminosity in…
We review constraints on models of the broad line region that are imposed by observations of the emission lines in Active Galactic Nuclei. Comparison of high and low ionization lines in sources with FWHM Hbeta < 4000 km/s points toward low…
Although accretion disks are a theoretically appealing model for the geometry and dynamics of the gas in the vicinity of black holes in Active Galactic Nuclei (AGN), there is little direct observational evidence for their existence. The…
Aperiodic optical variability is a common property of Active Galactic Nuclei (AGNs), though its physical origin is still open to question. To study the origin of the optical -- ultraviolet variability in AGN, we compare light curves of two…
We present Wide Field Spectrograph (WiFeS) integral field spectroscopy and HST FOS spectroscopy for the LINER galaxy NGC 1052. We infer the presence of a turbulent accretion flow forming a small-scale accretion disk. We find a large-scale…
One of the proposed explanations for the broad, double-peaked Balmer emission lines observed in the spectra of some active galactic nuclei (AGNs) is that they are associated with sub-parsec supermassive black hole (SMBH) binaries. Here, we…
Broad emission lines are emitted in the surroundings of supermassive black holes in the centers of active galactic nuclei (AGN). This region is spatially not resolved. We intend to get information on the structure and geometry of this broad…
Double-peaked line profiles are commonly considered a hallmark of rotating disks, with the distance between the peaks a measure of the rotation velocity. However, double-peaks can arise also from radiative transfer effects in optically…
The X-ray spectra of Active Galactic Nuclei (AGN) are complex and vary rapidly in time as seen in recent observations. Magnetic flares above the accretion disk can account for the extreme variability of AGN. They also explain the observed…
We study the disk emission component hidden in the single-peaked Broad Emission Lines (BELs) of Active Galactic Nuclei (AGN). We compare the observed broad lines from a sample of 90 Seyfert 1 spectra taken from the Sloan Digital Sky Survey…
Variability in emission lines is a characteristic feature in young stars and can be used as a tool to study the physics of the accretion process. Here we present a study of H{\alpha} variability in 15 T Tauri and Herbig Ae stars (K7-B2)…
Double-peaked [O III]5007, profiles in active galactic nuclei (AGNs) may provide evidence for the existence of dual AGNs, but a good diagnostic for selecting them is currently lacking. Starting from $\sim$ 7000 active galaxies in SDSS DR7,…
Recent studies have suggested that the short-timescale ($\lesssim7$ days) variability of the broad ($\sim$10,000 km s$^{-1}$) double-peaked H$\alpha$ profile of the LINER nucleus of NGC1097 could be driven by a variable X-ray emission from…
Most O and many B stars show unexplained cyclical variability in their spectral lines, i.e. modulation on the rotational timescale, but not strictly periodic. The variability occurs in the so-called discrete absorption components (DACs)…