相关论文: On the relation of optical obscuration and X-ray a…

Intrinsic absorption is a fundamental physical property to understand the evolution of active galactic nuclei (AGN). Here a sample of 1290 AGN, selected in the 2-10 keV band from different flux-limited surveys with very high optical…

The properties of the absorption in type 2, narrow line AGNs are reviewed by focusing on the X-ray indicators. I discuss the properties of the cold absorbing medium (the putative torus) and of the reprocessed components, as well as their…

We report the detection of ionized absorption in the ASCA spectrum of the narrow-line Seyfert 1 galaxy IRAS 17020+4544. Subsequent optical spectropolarimetry revealed high polarization increasing from 3% in the red to 5% in the blue,…

We investigate the far-infrared (far-IR) incidence of X-ray-selected active galactic nuclei (AGN) and non-AGN galaxies as a function of stellar mass (M$_*$), star formation rate (SFR), and specific black hole accretion rate…

X-ray spectroscopy offers an opportunity to study the complex mixture of emitting and absorbing components in the circumnuclear regions of active galactic nuclei, and to learn about the accretion process that fuels AGN and the feedback of…

Detection of absorbed active galactic nuclei and their properties remains an elusive and important problem in understanding the evolution and activation of black holes. With the very hard X-ray survey conducted by Swift's Burst Alert…

As the third paper of our serial studies that are aim at examining the AGN-host coevolution by using partially obscured AGNs, we extend the broad-line composite galaxies (composite AGNs) into ROSAT-selected Seyfert 1.8/1.9 galaxies basing…

We have used X-ray spectra to measure attenuating columns in a large sample of Seyfert galaxies. Over 30 of these sources have resolved radio jets, allowing the relative orientation of the nucleus and host galaxy to be constrained. We have…

We have compared the X-ray--to--optical flux ratios (F_x/F_opt) of absorbed active galactic nuclei (AGNs) in the Chandra Deep Field North (CDF-N) with those of nearby, optically classified Seyfert 2 galaxies. The comparison provides an…

We present the results of simultaneous XMM-Newton X-ray and 3.5m/CAHA optical spectroscopic observations of the Seyfert galaxy Mrk 993. This galaxy exhibited in the past significant variations of its broad emission lines which classified it…

We present a comparison of the gas and dust properties of the dense interstellar matter in six nearby star-forming regions (d<500 pc): rho Oph, Cha I, R CrA, IC 348, NGC 1333, and Orion. We measure from Chandra and XMM-Newton observations…

We investigate why half of X-ray--selected active galactic nuclei (AGN) in deep surveys lack signs of accretion in their optical spectra. The majority of these ``optically--dull'' AGN are no more than 6 times fainter than their host…

The emission and absorption attributes of the UV-blue nuclear spectra of the Narrow-Line Seyfert 1 (NLS1) galaxies are analyzed based on high quality archival HST observations. Measurements from composite spectra as well as from individual…

We present XMM-Newton spectral analysis of all 38 Seyfert galaxies from the Palomar spectroscopic sample of galaxies. These are found at distances of up to 67 Mpc and cover the absorbed 2-10 keV luminosity range ~10^38-10^43 ergs/s. Our aim…

X-ray emission detection in a galaxy is one of the efficient tools for selecting Active Galactic Nuclei (AGNs). However, many X-ray-selected AGNs are not easily selected as AGNs by their optical emission. These galaxies, so-called optically…

We present near-infrared spectra for a sample of galaxies with ambiguous optical emission line ratios. These galaxies fall between starbursts and Seyferts in the usual optical diagnostic diagrams. We find a similar result with the…

We present optical and X-ray data for a sample of serendipitous XMM-Newton sources that are selected to have 0.5-2 keV vs 2-4.5 keV X-ray hardness ratios which are harder than the X-ray background. The sources have 2-4.5 keV X-ray flux >=…

We aim to characterize the nature of galaxies whose optical emission line diagnostics are consistent with star formation, but whose X-ray properties strongly point towards the presence of an AGN. Understanding these sources is of particular…

Dust plays a central role in the unification theory of active galactic nuclei (AGNs). However, little is known about the nature (e.g., size, composition) of the dust which forms a torus around the AGN. In this Letter we report a systematic…

In this paper we discuss the X-ray properties of 49 local (z<0.035) Seyfert 2 galaxies with HST/WFC2 high-resolution optical coverage. It includes the results of 26 still unpublished Chandra and XMM-Newton observations, which yield 25 (22)…