Related papers: Testing the AGN Paradigm, Part I: a generic SED fo…
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…
The $BeppoSAX$ archive is currently the largest reservoir of high sensitivity simultaneous soft and hard-X ray data of Seyfert galaxies. From this database all the Seyfert galaxies (105 objects of which 43 are type I and 62 are type II)…
In this paper we study the properties of the optical spectra of Type 1 active galactic nuclei (AGNs) by using the unobscured hard X-ray emission as a diagnostic. We develop the `Correlation Spectrum Technique' (CST) and use this to show the…
We present an analysis of multi-timescale variability in line-of-sight X-ray absorbing gas as a function of optical classification in a large sample of Seyfert AGN to derive the first X-ray statistical constraints for clumpy-torus models.…
Understanding the Fe II emission from Active Galactic Nuclei (AGN) has been a grand challenge for many decades. The rewards from understanding the AGN spectra would be immense, involving both quasar classification schemes such as…
What main mechanisms set the star formation rate (SFR) of galaxies? This PhD thesis is a quest into the influences of gas and active galactic nuclei (AGNs) on the SFR, with particular focus on massive galaxies at z~2. First, a new code if…
Infrared interferometry of Seyfert galaxies has revealed that their warm ($300-400\,$K) dust emission originates primarily from polar regions instead of from an equatorial dust torus as predicted by the classic AGN unification scheme. We…
We present the 15 micron luminosity function of type 1 AGN (QSO + Seyfert 1). Our sample of 21 high-redshift sources is selected from the Preliminary Analysis catalogue in the S1 field of the European Large Area ISO Survey (ELAIS). To study…
We present an analysis of the first two XRISM/Resolve spectra of the well-known Seyfert-1.5 active galactic nucleus in NGC 4151, obtained in December 2023. Our work focuses on the nature of the narrow Fe K$_{\alpha}$ emission line at 6.4…
The broad band 0.1-200 keV spectra of a sample of 5 Seyfert 2 galaxies (NGC 7172, Mkn 3, NGC 2110, NGC 4507 and NGC 7674) have been measured within the first year of the $BeppoSAX$ Core program. All sources have been detected up to \~ 100…
The idea that some of the unusual features in the X-ray spectra of Narrow-Line Seyfert 1 galaxies (NLS1s) are due to the steep X-ray continuum is tested by comparing photoionization model calculations with various observed properties of…
We investigate the role of host galaxy classification and black hole mass in a heterogeneous sample of 276 mostly nearby (z<0.1) X-ray and IR selected AGN. Around 90% of Seyfert 1 AGN in bulge-dominated host galaxies (without disk…
We describe a complete, flux-density-limited sample of galaxies at redshift $0.8 < z < 1.3$ selected at 16 micron. At the selection wavelength near 8 micron rest, the observed emission comes both from dust heated by intense star formation…
We present the spectral energy distributions (SEDs) of a hard X-ray selected sample. The sample contains 136 sources with F(2-10 keV)>10^-14 erg/cm^2/s and 132 are AGNs. The sources are detected in a 1 square degree area of the…
We present low-resolution 5.5-35 um spectra for 103 galaxies from the 12 um Seyfert sample, a complete unbiased 12 um flux limited sample of local Seyfert galaxies selected from the IRAS Faint Source Catalog, obtained with the Infrared…
We present the first X-ray observations of three sources belonging to a new AGN class: the naked AGNs. Based on optical spectroscopic studies, these sources appear as classical type 2 (obscured) AGNs, with only narrow emission lines.…
In this work we present the most comprehensive INTEGRAL AGN sample which lists 272 objects. Here we mainly use this sample to study the absorption properties of active galaxies, to probe new AGN classes and to test the AGN unification…
Several studies of nearby active galactic nuclei (AGN) have shown that the soft X-ray emission presents a size and morphology that resembles that of the narrow-line region (NLR) traced by [O III]. Since the NLR is mainly constituted by gas…
We performed near-diffraction-limited (~0.4 FWHM) N-band imaging of one of the nearest Active Galactic Nucleus (AGN) in M51 with 8.2m Subaru telescope to study the nuclear structure and spectral energy distribution (SED) at 8-13 um. We…
As a result of deep hard X-ray observations by Chandra and XMM-Newton a significant fraction of the cosmic X-ray background (CXRB) has been resolved into individual sources. These objects are almost all active galactic nuclei (AGN) and…