相关论文: Powerful obscured AGN in Chandra cluster fields
We present evidence of the co-existence of either an AGN or an ultraluminous X-ray source (ULX), together with a young super stellar cluster in the 3 central parsecs of NGC4303. The galaxy contains a low luminosity AGN and hosts a number of…
We present the analysis of four NuSTAR observations of the luminous infrared galaxy merger NGC 6240, hosting a close pair of highly obscured active galactic nuclei (AGN). Over a period of about two years, the source exhibits hard X-ray…
We present the first results of ChaMP X-ray source properties obtained from the initial sample of 62 observations. The data have been uniformly reduced and analyzed with techniques specifically developed for the ChaMP and then validated by…
We report the discovery of two sources at z=3.867 and z=3.427 that exhibit powerful starburst and AGN activities. They benefit from data from radio to X rays from the CFHTLS-D1/SWIRE/XMDS surveys. Follow-up optical and near-infrared…
Heavily obscured accretion is believed to represent an important stage in the growth of supermassive black holes, and to play an important role in shaping the observed spectrum of the Cosmic X-ray Background (CXB). Hard X-ray (E$>$10 keV)…
We present X-ray source catalogs for the $\approx7$ Ms exposure of the Chandra Deep Field-South (CDF-S), which covers a total area of 484.2 arcmin$^2$. Utilizing WAVDETECT for initial source detection and ACIS Extract for photometric…
Our goal is to probe the populations of obscured and unobscured AGN investigating their optical-IR and X-ray properties as a function of X-ray flux, luminosity and redshift within a hard X-ray selected sample of 136 X-ray sources in the XMM…
The efficiency of mid-infrared selection methods for finding obscured AGN is investigated using data in the \chandra Deep Field North. It is shown that samples of AGN candidates compiled on the basis of mid-infrared colours only suffer…
We define a sample of 27 radio-excess AGN in the Chandra Deep Field North by selecting galaxies that do not obey the radio/infrared correlation for radio-quiet AGN and star-forming galaxies. Approximately 60% of these radio-excess AGN are…
We present first results of the X-ray spectral analysis of the 500 ksec deep survey obtained with XMM-Newton on the Chandra Deep Field South (CDFS). Statistical distributions of spectral index and intrinsic absorption are derived for a…
We present a multi-wavelength study of seven AGN at spectroscopic redshift >2.5 in the 7 Ms Chandra Deep Field South, selected to have good FIR/sub-mm detections. Our aim is to investigate the possibility that the obscuration observed in…
The cosmic history of the growth of supermassive black holes in galactic centers parallels that of star-formation in the Universe. However, an important fraction of this growth occurs inconspicuously in obscured objects, where…
We report on a NuSTAR and XMM-Newton program that has observed a sample of three extremely luminous, heavily obscured WISE-selected AGN at z~2 in a broad X-ray band (0.1 - 79 keV). The parent sample, selected to be faint or undetected in…
The existence of a large population of Compton thick (CT, $N_{H}>10^{24} cm^{-2}$) AGN is a key ingredient of most Cosmic X-ray background synthesis models. However, direct identification of these sources, especially at high redshift, is…
Observations and theoretical simulations suggest that a significant fraction of merger-triggered accretion onto supermassive black holes is highly obscured, particularly in late-stage galaxy mergers, when the black hole is expected to grow…
We present an analysis of the X-ray bright point source population in 43 massive clusters of galaxies observed with the Chandra X-ray Observatory. We have constructed a catalog of 4210 rigorously selected X-ray point sources in these…
The co-evolution of host galaxies and the active black holes which reside in their centre is one of the most important topics in modern observational cosmology. Here we present a study of the properties of obscured Active Galactic Nuclei…
In this letter we report the detection of an extremely strong X-ray emission line in the 940ks chandra ACIS-I spectrum of CXO CDFS J033225.3-274219. The source was identified as a Type1 AGN at redshift of z = 1.617, with 2.0 -- 10.0 keV…
Compton Thick (CT) AGN are a key ingredient of Cosmic X-ray Background (CXB) synthesis models, but are still an elusive component of the AGN population beyond the local Universe. Multi-wavelength surveys are the only way to find them at z >…
We present new X-ray and optical spectroscopy of a Type 2 quasar candidate selected from a follow-up program of hard, optically-dim, serendipitous Chandra sources. The source is confirmed to be a Type 2 quasar at z=0.536 with an intrinsic…