Related papers: Covering factor in AGNs: evolution versus selectio…

The FeII/MgII line flux ratio has been used to investigate the chemical evolution of high redshift active galactic nuclei (AGNs). No strong evolution has been found out to z~6, implying that the type 1a supernova activity has been already…

Conservation of the phase-space density of photons plus Lorentz invariance requires that the cosmological luminosity distance be larger than the angular diameter distance by a factor of $(1+z)^2$, where $z$ is the redshift. Because this is…

Aims: We aim to find torus models that explain the observed high-resolution mid-infrared (MIR) measurements of active galactic nuclei (AGN). Our goal is to determine the general properties of the circumnuclear dusty environments. Methods:…

In this paper, I have attempted to highlight key results from deep extragalactic surveys at mid-infrared wavelengths. I discuss advances in our understanding of dust enshrouded star-formation and AGN activity at 0<z<3 from IRAS, ISO and…

Active galactic nuclei (AGN) that show strong rest-frame optical/UV variability in their blue continuum and broad line emission are classified as "changing-look" AGN, or at higher luminosities changing look quasars (CLQs). These…

We examine the far-IR properties of a sample of 5391 optically selected QSOs in the 0.5<z<2.65 redshift range down to log[nuLnu,2500 (erg/s)]>44.7, using SPIRE data from Herschel-ATLAS. We split the sample in a grid of 74…

Models of galaxy evolution assume some connection between the AGN and star formation activity in galaxies. We use the multi-wavelength information of the CDFS to assess this issue. We select the AGNs from the 3Ms XMM-Newton survey and…

We present an analysis of four complete samples of radio-loud AGN (3CRR, 2Jy, 6CE and 7CE) using near- and mid-IR data taken by the Wide-Field Infrared Survey Explorer (WISE). The combined sample consists of 79 quasars and 273 radio…

We have combined the CLASXS Chandra survey in Lockman with the Spitzer SWIRE survey data to study the X-ray-infrared connection for AGN. The sample consists of 401 X-ray-sources, of which 306 are detected by Spitzer, and a further 257 AGN…

We wish to relate the degree scale structure of galactic diffuse clouds to sub-arcsecond atomic and molecular absorption spectra obtained against extragalactic continuum background sources. To do this, we used the ARO 12m telescope to map…

We present the results from an X-ray spectral analysis of active galactic nuclei (AGN) in the Chandra Deep Field-South, AEGIS-XD and Chandra-COSMOS surveys, focussing on the identification and characterisation of the most heavily obscured,…

We present the results of a CO line survey of 30 galaxies at moderate redshift (z \sim 0.2-0.6), with the IRAM 30m telescope, with the goal to follow galaxy evolution and in particular the star formation efficiency (SFE) as defined by the…

We fitted the optical to mid-infrared (MIR) spectral energy distributions (SEDs) of ~15000 type-I, 0.75<z<2, active galactic nuclei (AGNs) in an attempt to constrain the properties of the physical component responsible for the rest-frame…

We examine the clustering of quasars over a wide luminosity range, by utilizing 901 quasars at $\overline{z}_{\rm phot}\sim3.8$ with $-24.73<M_{\rm 1450}<-22.23$ photometrically selected from the Hyper Suprime-Cam Subaru Strategic Program…

Obscured AGN represent a significant fraction of the entire AGN population, especially at high redshift (~70% at z=3--5). They are often characterized by the presence of large gas and dust reservoirs that are thought to sustain and possibly…

The symmetry axes of active galactic nuclei (AGN) are randomly distributed in space but highly inclined sources are heavily obscured and are not seen as quasars with broad emission lines. The obscuring torus geometry determines the average…

We analyze a sample of 30,000 nearby obscured AGNs with optical spectra from SDSS and mid-IR photometry from WISE. Our aim is to investigate the AGN host galaxy properties with mid-IR luminosities as AGN activity indicator, and to compare…

Properties of CFRS field galaxies up to z=1 are discussed. Estimations of the cosmic star formation rate (SFR) lead to serious problems if they not account for AGN emissions and for light reemitted at IR wavelengths. Deep ISOCAM and VLA…

We report herschel observations of 100 very luminous, optically selected AGNs at z=2-3.5 with log(LUV)(erg/sec)> 46.5, where LUV=L1350A. The distribution in LUV is similar to the general distribution of SDSS AGNs in this redshift and…

Dust torus plays the key role in determining active galactic nuclei (AGN) observational appearance. Here, the scenario of accretion regulated central dust torus is tested for the first time in the individual changing-look AGN (CLAGN) SDSS…