Related papers: Average Quasar Spectra in the Context of Eigenvect…
[Abridged] We compute the virial mass of the central black hole (M) and the luminosity-to-mass (L/M) ratio of ~ 300 low-z quasars and luminous Seyfert 1 nuclei. We analyze: (1) whether radio-quiet and radio-loud objects show systematic…
To find the spectral properties of AGNs in optical spectral band (around the Hb line) we constructed an Fe II template, that is covering Fe II emission from 4100 A to 5600 A. Using the new Fe II template we explored spectral properties of…
We consider the properties of radio-loud (RL) AGN in the context of the Eigenvector 1 (E1) parameter space. RL sources show a restricted E1 parameter space occupation relative to the radio-quiet (RQ) majority. The Fanaroff-Riley II ``parent…
With a quasar sample designed for studying orientation effects, we investigate the orientation dependence of characteristics of the C IV 1549 broad emission line in approximately 50 Type 1 quasars with z=0.1-1.4. Orientation is measured for…
Direct correlations and a Principal Component Analysis (PCA) are presented for a complete sample of 110 soft X-ray selected AGN of which about half are Narrow-Line Seyfert 1 galaxies (NLS1s). The direct correlation analyses show that…
Here we investigate the kinematics of the part of the broad line region (BLR) in active galactic nuclei (AGNs) emitting H$\beta$ and H$\alpha$ emission lines. We explore the widths and asymmetries of the broad H$\beta$ and H$\alpha$…
We report on a spectral principal component analysis (SPCA) of a sample of 816 quasars, selected to have small Fe II velocity shifts with spectral coverage in the rest wavelength range 3500--5500 \AA. The sample is explicitly designed to…
Moderate-resolution spectra of the H$\beta$--[O III] $\lambda$5007 region have been obtained for 41 radio-loud quasars in order to investigate relationships among their broad- and narrow-line profiles, radio structures, and X-ray…
Eigenvector 1 (EV1) was found to be the dominant component behind the significant correlations for the measured parameters in quasar spectra (Boroson & Green, 1992). The parameter R$_{\mathrm{FeII}}$, which strongly correlates to the EV1,…
The UV spectral range (1100 - 3000 A) contains the strongest resonance lines observed in active galactic nuclei (AGN). Analysis of UV line intensity ratios and profile shapes in quasar spectra provide diagnostics of physical and dynamical…
The broad emission lines commonly seen in quasar spectra have velocity widths of a few per cent of the speed of light, so special- and general-relativistic effects have a significant influence on the line profile. We have determined the…
We present the results of a long-term variability campaign of very broad-line AGNs with line widths broader than FWHM $>$ 5000 kms$^{-1}$. The main goal of our investigation was to study whether the widths of the optical broad emission…
Recent ROSAT studies of narrow-line Seyfert 1 galaxies revealed these objects (with FWHM $H_{\beta} \le 2000 km s^{-1}$) generally show steeper soft X-ray spectra than broad line Seyfert 1's and that there are no AGN with broad lines and…
The width of the broad H-beta emission line is the primary defining characteristic of the NLS1 class. This parameter is also an important component of Boroson and Green's optical Eigenvector 1 (EV1), which links steeper soft X-ray spectra…
We present a statistical analysis of the optical properties of an X-ray selected Type 1 AGN sample, using high signal to-noise ratio ($S/N>20$) spectra of the counterparts of the ROSAT/2RXS sources in the footprint of the SDSS-IV/SPIDERS…
We present a comprehensive spectroscopic and variability-based characterisation of a sample of low-luminosity active galactic nuclei (AGNs) hosting low mass black holes, identified by $H\beta$ full width at half maximum (FWHM) $< 2200$ km…
Eigenvector 1 (EV1) is the formal parameter which allows the introduction of some order in the properties of the unobscured type 1 active galaxies. We aim to understand the nature of this parameter by analyzing the most extreme examples of…
We investigated the optical FeII emission in a sample of about 215 low-redshift AGN (quasars and luminous Seyfert 1 galaxies). We find that a scaled and broadened FeII template based on the I Zw 1 spectrum can satisfactorily model the FeII…
We divide a sample of 302 type-1 AGNs into two subsamples based on the narrow line [OIII]/Hbeta_{NLR} ratio, since we expect that there will be a stronger starburst (HII region) contribution to the narrow line emission for…
We explore the influence of optical Fe II quasi-continuum on the measured spectral parameters in the 4150-5500 A range for the spectra of Type 1 active galactic nuclei (AGNs). We assume that the broad line region is composed of two…