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Active Galactic Nuclei (AGNs) are powerful energy sources in the Universe, emitting radiation from the gamma to radio spectral range. Different physical processes are present in the emitting plasma around the super-massive black hole, that is supposed to be in the center of an AGN. Here we present an overview of plasma conditions in emitting regions of AGNs. We start from the X-ray emitting region, which is close to the super-massive black hole, discussing the physics and geometry of the region. In more details we discuss the plasma that emits broad emission lines, i.e. the Broad Line Region, and at the end we present methods to determine the plasma conditions in the Narrow Line Emitting Region using forbidden, collisionally excited, emission lines. [ABSTRACT FROM AUTHOR]

Active Galactic Nuclei (AGN) are the most luminous objects in the Universe. It is widely accepted that radiation emitted from these objects originates in an accretion disk around a Supermassive Black Hole (SMBH). Emission spectral lines (in the X-ray and UV/optical) are used to investigate the plasma conditions in the vicinity of the SMBH. Here we give a short overview of the emission line profiles and their usage for determination of kinematics (geometry) of emitting plasma around black hole. [ABSTRACT FROM AUTHOR]

In order to probe the physical properties of the emitting plasma in the broad line region (BLR) of active galactic nuclei (AGN), we perform a number of numerical simulations with the photoionization code CLOUDY. We investigate the Balmer and helium line ratios in order to find conditions in the BLR where so-called Boltzmann-plot (BP) method is applicable. We found correlations between average temperature, hydrogen density and He II/He I line ratio in the case where BP is present. [ABSTRACT FROM AUTHOR]

In the spectra of Hot Emission Stars and AGNs we observe some peculiar profiles that result from dynamical processes such as accretion and/or ejection of matter from these objects. In this paper we indicate that DACs and SACs phenomena, can explain the spectral lines peculiarity in Hot Emission Stars and AGNs. We also try to connect the physical properties of absorption regions around stars and quasars. [ABSTRACT FROM AUTHOR]

In the UV spectrum of AX Mon (HD 45910) we observe a series of spectral lines with complex structure and peculiar profiles. This peculiarity is due to SACs or DACs. In this paper, using the GR model, we study the complex profile of Fe II spectral lines and we calculate the relation of some kinematical parameters of the regions that create the DACs/SACs with the excitation potential. [ABSTRACT FROM AUTHOR]

The complex structure and the peculiar profiles of some spectral lines are common in the UV spectrum of AX Mon (HD 45910). The observed peculiar profiles are composed by a number of SACs or DACs. In this paper, using the GR model, we study the complex profile of the Al II (λ 1670.81 Å), Al III (λλ 1854.722, 1867.782 Å), Mg II (λλ 2795.523, 2802.698 Å), Fe II (λ 2586.876 Å), C II (λλ 1334.515, 1335.684 Å) and Si IV (λλ 1393.73, 1402.73 Å) spectral lines. Additionally, we calculate the relation of some kinematical parameters of the regions that create the DACs/SACs of the studied lines with the ionization potential. [ABSTRACT FROM AUTHOR]

In this paper we study the Lyα spectral line and the N V, Si IV and C IV resonance lines in the UV spectrum of the Broad Absorption Line Quasar (BAL QSO) PG 1254+047. We found that the studied Broad Absorption Lines (BALs) of this quasar are created by a number of Satellite Absorption Components (SACs). We calculated some kinematical parameters such as the apparent rotational (Vrot) and radial (Vrad) velocities of the regions where the studied lines are created and the random velocities (Vrand) of the studied ions. [ABSTRACT FROM AUTHOR]

In this paper we study the C IV and Si IV resonance lines in the UV spectrum of the Broad Absorption Line Quasar (BAL QSO) PG 0946+301. The studied Broad Absorption Lines (BALs) are mainly created by a number of Satellite Absorption Components (SACs). However, the C IV doublet of PG 0946+301 is one of the very few lines that present clearly the DACs phenomenon, in the case of quasars. We applied the GR model and we calculated the apparent rotational (Vrot) and radial (Vrad) velocities of the regions where the studied lines are created and the random velocities (Vrand) of the C IV and Si IV ions. [ABSTRACT FROM AUTHOR]

Investigations of the Stark line broadening parameters are important for a number of problems in laboratory and astrophysical plasma research. We use a modified semiempirical approach in order to complete a set of the Stark broadening data. Here we present the Stark broadening data for 6 Ag II spectral lines calculated within the modified semiempirical approach. [ABSTRACT FROM AUTHOR]

We have analysed the Lyα, Hβ and Hα line profiles of three active galactic nuclei: quasar 3C390.3 and two Seyfert 1 galaxies; Akn 120 and III Zw2. The blueand red-shifted broad Gaussian components which are present in all considered 3C390.3 and Akn 120 lines cannot be explained by an accretion disk model because of the lines' variation on longer time-scales. On the other hand, the line profiles as well as the variation of the III Zw2 spectral line shapes can be explained by an accretion disk model. [ABSTRACT FROM AUTHOR]