Related papers: Improved Fe II emission line models for AGN using …

We use the sample of emission-line nuclei derived from a recently completed optical spectroscopic survey of nearby galaxies to quantify the incidence of local (z = 0) nuclear activity. Consistent with previous studies, we find detectable…

We study the relation of active galactic nuclei (AGNs) to star formation in their host galaxies. Our sample includes 205 Type-1 and 85 Type-2 AGNs, 162 detected with Herschel, from fields surrounding 30 galaxy clusters in the Local Cluster…

The unified model of active galactic nuclei (AGN) claims that the properties of AGN depend on the viewing angle of the observer with respect to a toroidal distribution of dust surrounding the nucleus. Both the mid-infrared (MIR) attenuation…

We measure the Eddington ratio distribution of local optical narrow-line active galactic nuclei (AGN) as a function of host galaxy properties, as a potential test of galaxy formation theories of AGN feedback. We extract central…

We combine near-to-mid-IR Spitzer data with shorter wavelength observations (optical to X-rays) to get insights on the properties of a sample of luminous, obscured Active Galactic Nuclei (AGN). We aim at modeling their broad-band Spectral…

Active Galactic Nuclei (AGN) are believed to be one of the main source candidates for the high-energy (TeV-PeV) cosmic neutrino flux recently discovered by the IceCube neutrino observatory. Nevertheless, several correlation studies between…

We present the emission properties of a sample of 3,579 type 1 AGN, selected based on the detection of broad H-alpha emission. The sample covers the range of black hole mass 10^6<M_BH/M_Sun<10^9.5 and luminosity in Eddington units 10^-3 <…

Modelling the low ionization lines (LIL) in active galactic nuclei still faces problems in explaining the observed equivalent widths (EWs). We examine the optical Fe II and near-infrared Ca II triplet (CaT) emission strengths using the…

A full set of calculations is presented for inner-shell n = 2 to 3 photoexcitation of the 16 iron charge states: Fe I through Fe XVI. The blend of the numerous absorption lines arising from these excitations (mainly 2p - 3d) forms an…

We have cross-correlated the Sloan Digital Sky Survey (SDSS) second data release spectroscopic galaxy sample with the IRAS faint-source catalogue (FSC). Optical emission line ratios are used to classify the galaxies with reliable IRAS 60…

Active Galactic Nuclei (AGN) are intertwined with galaxy evolution, injecting energy into the interstellar medium (ISM) that could regulate star formation as a galaxy evolves. However, the phenomena through which we observe AGN are…

Strong He II emission is produced by low-metallicity stellar populations. Here, we aim to identify and study a sample of He II $\lambda 1640$-emitting galaxies at redshifts of $z \sim 2.5-5$ in the deep VANDELS spectroscopic survey.. We…

The dusty environments (= "dust tori'') of AGN are now in reach of observations. Following our paper I on ground-based mid-IR spectro-photometry (H\"onig et al. 2010), we present an upgrade to our radiative transfer model of 3-dimensional…

(abridged)The majority of Active Galactic Nuclei (AGN) suffer from significant obscuration by surrounding dust and gas. X-ray surveys in the 2-10 keV band will miss the most heavily-obscured AGN in which the absorbing column density exceeds…

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…

Galactic superwinds occur in almost all infrared-luminous galaxies with star formation rates (SFRs) above 10 M_sun/yr, as shown by studies of the NaI D interstellar absorption line. We demonstrate that this result also applies to…

Modeling the spectral energy distribution (SED) of active galactic nuclei (AGN) plays a very important role in constraining modern cosmological simulations of galaxy formation. Here, we utilize an advanced supermassive black hole (SMBH)…

We present spectra of the nuclear regions of 50 nearby (D = 1 - 92 Mpc, median = 20 Mpc) galaxies of morphological types E to Sm. The spectra, obtained with the Gemini Near-IR Spectrograph on the Gemini North telescope, cover a wavelength…

An integral part of the Unified Model for Active Galactic Nuclei (AGNs) is an axisymmetric obscuring medium, which is commonly depicted as a torus of gas and dust surrounding the central engine. However, a robust, dynamical model of the…

Previous studies of the Na I D interstellar absorption line doublet have shown that galactic winds occur in most galaxies with high infrared luminosities. However, in infrared-bright composite systems where a starburst coexists with an…