Related papers: A Model for Type 2 Coronal Line Forest (CLiF) AGN
We have obtained Keck NIR spectroscopy of a sample of nine M$_\star$ $<$ 10$^{10}$ M$_\odot$ dwarf galaxies to confirm AGN activity and the presence of galaxy-wide, AGN-driven outflows through coronal line (CL) emission. We find strong CL…
We use the photoionisation code Cloudy to determine both the location and the kinematics of the optical forbidden, high ionisation line (hereafter, FHIL) emitting gas in the narrow line Seyfert 1 galaxy Ark 564. The results of our models…
We present the two--point correlation function (2PCF) of narrow-line active galactic nuclei (AGN) selected within the First Data Release of the Sloan Digital Sky Survey. Using a sample of 13605 AGN in the redshift range 0.055 < z < 0.2, we…
Coronal lines (CLs), which arise from collisionally excited forbidden transitions from highly ionized species, are a powerful diagnostic tool in uncovering active galactic nuclei (AGNs) and constraining their properties. However, recent…
We analyze observations obtained with the Chandra X-ray Observatory of bright Compton thick active galactic nuclei (AGNs), those with column densities in excess of 1.5 x 10^{24} cm^{-2} along the lines of sight. We therefore view the…
We have compared the optical emission line ratios of type 2 quasars from Zakamska et al. with standard AGN photoionization model predictions, Seyfert 2s, HII galaxies, and narrow line FRII radio galaxies. Moderate to high ionization narrow…
We report the new finding that type 1 Seyfert nuclei (S1s) have excess [FeVII]6087 emission with respect to type 2s (S2s). The S1s exhibit broad emission lines which are attributed to ionized gas within 1 pc of the black hole, whereas the…
We select a sample of 90 obscured (type2) AGN with 1.45<z<3.05 from the zCOSMOS-deep galaxy sample by 5 sigma-detection of the high-ionization CIV {\lambda}1549 narrow emission line. The presence of this feature in a galaxy spectrum is…
We investigate the relation between star formation (SF) and black hole accretion luminosities, using a sample of 492 type-2 active galactic nuclei (AGNs) at z < 0.22, which are detected in the far-infrared (FIR) surveys with AKARI and…
Iron K-alpha lines are key diagnostics of the central regions of AGN. Their profiles indicate that they are formed deep in the potential well of the central black hole, where extreme broadening and red shift occur. The profiles are most…
The anisotropic nature of active galactic nuclei (AGN) is thought to be responsible for the observational differences between type-1 (pole-on) and type-2 (edge-on) nearby Seyfert-like galaxies. In this picture, the detection of emission…
Type 2 AGN are by definition nuclei in which the broad-line region and continuum light are hidden at optical/UV wavelengths by dust. Via accurate registration of infrared (IR) Very Large Telescope adaptive optics images with optical…
Accretion flows toward black holes can be of a quite different nature, described as an optically thick cool gas flow in a disk for high accretion rates or as a hot coronal optically thin gas flow for low accretion rates, possibly affected…
We describe improved modelling of the emission by dust in a toroidal--like structure heated by a central illuminating source within Active Galactic Nuclei (AGN). We chose a simple but realistic torus geometry, a flared disc, and a dust…
The spectra of Active Galactic Nuclei (AGNs) are often characterized by a wealth of emission lines with different profiles and intensity ratios that led to a complicated classification. Their electro-magnetic radiation spans more than 10…
"Changing-look" active galactic nuclei (CL-AGNs) challenge our basic ideas about the physics of accretion flows and circumnuclear gas around supermassive black holes. Using first-year Sloan Digital Sky Survey V (SDSS-V) repeated…
Significant variability in broad emission line strengths of active galactic nuclei (AGN) over months to years has been observed, often accompanied by intrinsic continuum changes. Such spectral variability challenges the traditional AGN…
We determine the intrinsic shapes and orientations of 27,450 type I and II active galactic nucleus (AGN) galaxies in the spectroscopic sample of the SDSS DR7, by studying the distribution of projected axis ratios of AGN hosts. Our aim is to…
Kilo-parsec scale hard ($>$ 3 keV) X-ray continuum and fluorescent Fe K$\alpha$ line emission has been recently discovered in nearby Compton-thick (CT) active galactic nuclei (AGN), which opens new opportunities to improve AGN torus…
Active galactic nuclei (AGN) and galactic black hole binaries (GBHs) represent two classes of accreting black holes. They both contain an accretion disc emitting a thermal radiation, and a non-thermal X-ray emitting corona. GBHs exhibit…