Related papers: Long-Term Profile Variability of Double-Peaked Emm…
An increasing number of AGNs exhibit broad, double-peaked Balmer emission lines, which are thought to arise from the outer regions of the accretion disk which fuels the AGN. The line profiles are observed to vary on a characteristic…
An increasing number of Active Galactic Nuclei (AGNs) exhibit broad, double-peaked Balmer emission lines,which represent some of the best evidence for the existence of relatively large-scale accretion disks in AGNs. A set of 20…
About 3-10\% of Type I active galactic nuclei (AGN) have double-peaked broad Balmer lines in their optical spectra originating from the motion of gas in their accretion disk. Double-peaked profiles arise not only in AGN, but occasionally…
We summarize the optical, UV, and X-ray properties of double-peaked emitters -- AGN with double-peaked Balmer emission lines believed to originate in the AGN accretion disk. We focus on the X-ray spectroscopic results obtained from a new…
We present up to two decades of spectroscopic monitoring of the double-peaked broad Halpha emission lines of seven broad-line radio galaxies. These extremely broad, double-peaked lines are successfully modeled by emission from gas in the…
We present a new sample of 116 double-peaked Balmer line Active Galactic Nuclei (AGN) selected from the Sloan Digital Sky Survey. Double-peaked emission lines are believed to originate in the accretion disks of AGN, a few hundred…
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…
We report the completion of a survey of radio-loud AGNs begun in an earlier paper, aimed finding and studying broad, double-peaked Balmer lines. We present Ha spectra of 13 broad-lined objects (3 with double-peaked Ha profiles). The final…
Broad (~10,000 km/s), double-peaked emission-line profiles of Balmer lines emitted by active galactic nuclei (AGN) are thought to originate in the outer parts of an accretion disk surrounding a nuclear supermassive black hole (SMBH), at…
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…
I review the distinguishing observational characteristics of active galaxies with double-peaked emission lines and their implications for the nature of the line-emitting region. Since double-peaked lines most likely originate in the outer…
Double-peaked Balmer-line profiles originate in the accretion disks of a few percent of optically selected AGN. The reasons behind the strong low-ionization line emission from the accretion disks of these objects is still uncertain. In this…
The Broad Emission Lines (BELs) in spectra of type 1 Active Galactic Nuclei (AGN) can be very complex, indicating a complex Broad Line Region (BLR) geometry. According to the standard unification model one can expect an accretion disk…
We present the results of UV spectroscopy of AGNs with double-peaked Balmer emission lines. In 2/3 of the objects, the far-UV resonance lines are strong, with single-peaked profiles resembling those of Seyfert galaxies. The Mg II line is…
A small number of LINERs have been seen to display variable H-alpha emission with a very broad, double-peaked profile. Recent observations with the Hubble Space Telescope indicate that such emission may be a common attribute of LINERs. The…
Double-peaked (DP) broad emission line profiles in active galactic nuclei (AGNs) are often interpreted as signatures of rotating disk-like structures in the broad-line region (BLR) and are commonly observed in low-luminosity AGNs using…
We present optical and X-ray spectra of a radio-quiet X-ray selected AGN, RX J1042+1212 ($z$=0.271). The Halpha and Hbeta emission lines are very broad (with full widths at half maximum of ~10000 km s-1) and have double-peaked profiles.…
The broad (FWHM ~ 10,000 km/s) double-peaked H{\alpha} profile from the LINER/Seyfert 1 nucleus of NGC 1097 was discovered in 1991, and monitored for the following 11 years. The profile showed variations attributed to the rotation of gas in…
A fraction of active galactic nuclei (AGN) have double-peaked H$\alpha$, H$\beta$ and Mg II broad lines attributed to emission from rotating gas in the accretion disk. Using optical spectroscopy of a flux-limited sample of AGN selected via…
Multi-wavelength observations of active galactic nuclei (AGNs) often reveal various time scales of variability. Among these phenomena, "changing-look AGNs" are extreme cases where broad emission lines become faint/bright or even…