相关论文: Detecting Obscured AGN in the Distant Universe wit…

We present a new method to predict the line-of-sight column density (NH) values of active galactic nuclei (AGN) based on mid-infrared (MIR), soft, and hard X-ray data. We developed a multiple linear regression machine learning algorithm…

In this paper, results of optical identification of ASCA surveys are summarized. To understand luminous AGNs in the z<1 universe, the ASCA AGN sample is still better than samples of AGNs from deep Chandra or XMM-Newton surveys. Combining…

Compton-thick active galactic nuclei (CT-AGNs), defined by column density $\mathrm{N_H} \geqslant 1.5 \times 10^{24} \ \mathrm{cm}^{-2}$, are so heavily absorbed that their X-ray emission is often feeble, even undetectable by X-ray…

We provide X-ray constraints and perform the first X-ray spectral analyses for bright (f_850>=5mJy; S/N>=4) SCUBA sources in an 8.4'x8.4' area of the 2 Ms Chandra Deep Field-North survey containing the Hubble Deep Field-North. X-ray…

For measurement of the AGN luminosity function and its evolution, X-ray selection samples all types of AGN and provides reduced obscuration bias in comparison with UV-excess or optical surveys. The apparent decline in optically-selected…

We present XMM-Newton observations of three AGN taken as part of a hunt to find very heavily obscured Compton-thick AGN. For obscuring columns greater than 10^25 cm^-2, AGN are only visible at energies below 10 keV via reflected/scattered…

AIMS. This work addresses the AGN IR-selection dependency on intrinsic source luminosity and obscuration, in order to identify and charaterise biases which could affect conclusions in studies. METHODS. We study IR-selected AGN in the…

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 use Chandra data to study the incidence and properties of Active Galactic Nuclei (AGN) in 16 intermediate redshift ($0.5 < z < 1.1$) X-ray-selected galaxy groups in the Chandra Deep Field-South. We measure an AGN fraction of $f(L_{X,H} >…

We present a detailed analysis of the most luminous and obscured Active Galactic Nuclei (AGNs) detected in the ultra-hard X-ray band (14-195 keV) by Swift/BAT. Our sample comprises 21 X-ray luminous (log $L_X/{\rm erg\,s^{-1}}>44.6$, 2-10…

We present the X-ray analysis of the most luminous obscured active galactic nuclei (AGN) inside local ultraluminous infrared galaxies (ULIRGs). Our sample consists of ten sources, harbouring AGN components with estimated luminosity in…

In deep X-ray surveys, active galactic nuclei (AGNs) with a broad range of luminosities have been identified. However, cosmologically distant low-luminosity AGN (LLAGN, $L_{\mathrm{X}} \lesssim 10^{42}$ erg s$^{-1}$) identification still…

We present a detailed X-ray spectral analysis of a complete sample of hard X-ray selected AGN in the Northern Galactic Cap of the 58-month Swift Burst Alert Telescope (Swift/BAT) catalog, consisting of 100 AGN with b>50deg. This region has…

We present the X-ray spectral analysis of the 1855 extragalactic sources in the Chandra COSMOS-Legacy survey catalog having more than 30 net counts in the 0.5-7 keV band. 38% of the sources are optically classified Type 1 active galactic…

We present the results of calculations of the cosmic AGN background spectrum from 3 keV (4\times 10^{-4} microns) to 1000 microns. These computations make use of the measured X-ray luminosity function and its evolution, as well as fits from…

Recent X-ray surveys have provided a large number of high-luminosity, obscured Active Galactic Nuclei (AGN), the so-called Type 2 quasars. Despite the large amount of multi-wavelength supporting data, the main parameters related to the…

We present a multi-waveband analysis of a 126 galaxy sub-sample of the 12 micron galaxy sample (12MGS), for which we have carried out a detailed X-ray spectral analysis of in a previous paper. We present optical activity classes and we…

We investigate the nature of far-infrared (70 um) and hard X-ray (3-24 keV) selected galaxies in the COSMOS field detected with both Spitzer and Nuclear Spectroscopic Telescope Array (NuSTAR). By matching the Spitzer-COSMOS catalog against…

We perform long-term ($\approx 15$ yr, observed-frame) X-ray variability analyses of the 68 brightest radio-quiet active galactic nuclei (AGNs) in the 6 Ms $Chandra$ Deep Field-South (CDF-S) survey; the majority are in the redshift range of…

Deep X-ray surveys provide the most efficient identification of Active Galactic Nuclei (AGN) activity. However, recent evidence has indicated that the current <10 keV surveys do not detect the most heavily obscured AGNs. Here we explore…