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We present the properties of X-ray detected dust obscured galaxies (DOGs) in the Chandra Deep Field South. In recent years, it has been proposed that a significant percentage of the elusive Compton-thick (CT) active galactic nuclei (AGN)…

Astrophysics of Galaxies · Physics 2016-08-10 A. Corral , I. Georgantopoulos , A. Comastri , P. Ranalli , A. Akylas , M. Salvato , G. Lanzuisi , C. Vignali , L. Koutoulidis

We present the X-ray properties of 108 Dust-Obscured Galaxies (DOGs; F$_{24 \mu m}$/F$_{R} >$ 1000) in the COSMOS field, all of which detected in at least three far-infrared bands with the Herschel Observatory. Out of the entire sample, 22…

We present X-ray spectral analysis of the brightest sources (f_{2-10 keV}>10^{-15}$ cgs) in the Chandra Deep Field North. Our sample consists of 222 sources; for the vast majority (171) either a spectroscopic or a photometric redshift is…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-02 I. Georgantopoulos , A. Akylas , A. Georgakakis , M. Rowan-Robinson

We present a detailed X-ray spectral analysis of 1152 AGNs selected in the Chandra Deep Fields (CDFs), in order to identify highly obscured AGNs ($N_{\rm H} > 10^{23}\ \rm cm^{-2}$). By fitting spectra with physical models, 436 (38%)…

We present X-ray spectra of 185 bright sources detected in the XMM-Newton deep survey of the Chandra Deep Field South, combining the three EPIC cameras. The 2-10 keV flux limit of the sample is 2e-15 erg/s/cm2. The sources are distributed…

We present a detailed X-ray spectral analysis of the sources in the 1Ms catalog of the Chandra Deep Field South (CDFS) taking advantage of optical spectroscopy and photometric redshifts for 321 sources. As a default spectral model, we adopt…

We briefly report here on our ongoing X-ray spectroscopy and variability analyses of 136 faint X-ray sources discovered in the 2 Ms Chandra Deep Field North observations spanning 1.4x10-15 to 2x10-13 ergs s-1 cm-2. Most sources are…

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…

Astrophysics · Physics 2009-11-13 J. L. Donley , G. H. Rieke , J. R. Rigby , P. G. Perez-Gonzalez

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,…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Murray Brightman , Kirpal Nandra , Mara Salvato , Li-Ting Hsu , Cyprian Rangel

A large population of heavily obscured, Compton Thick AGNs is predicted by models of galaxy formation, models of Cosmic X-ray Background and by the ``relic'' super-massive black-hole mass function measured from local bulges. However, so far…

With an aim to unveil the population of obscured AGN hosted in high-$z$ dust-obscured galaxies (DOGs), we performed X-ray spectral study of $34$ DOGs ($0.59$ $\leq$ $z$ $\leq$ $4.65$) lying within $5.3$ deg$^{2}$ of the XMM-SERVS coverage…

Astrophysics of Galaxies · Physics 2024-05-13 Abhijit Kayal , Veeresh Singh

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…

Astrophysics · Physics 2009-11-13 I. Georgantopoulos , A. Georgakakis , M. Rowan-Robinson , E. Rovilos

We study the properties of a sample of 211 heavily-obscured Active Galactic Nucleus (AGN) candidates in the Extended Chandra Deep Field-South selecting objects with f_24/f_R>1000 and R-K>4.5. Of these, 18 were detected in X-rays and found…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 E. Treister , C. Cardamone , K. Schawinski , C. M. Urry , E. Gawiser , S. Virani , P. Lira , J. Kartaltepe , M Damen , E. N. Taylor , E. Le Floc'h , Stephen Justham , A. Koekemoer

We present Chandra and Spitzer data of the 186, extragalactic, hard 2-10 keV X-ray selected sources, which lie in the central part of the Chandra Deep Field South (CDFS). For the vast majority of sources (99.5%) there is a spectroscopic or…

Astrophysics · Physics 2009-11-11 I. Georgantopoulos , A. Georgakakis , A. Akylas

Dust-obscured galaxies (DOGs) with extreme infrared luminosities may represent a key phase in the co-evolution of galaxies and supermassive black holes. We select 12 DOGs at $0.3\lesssim z\lesssim1.0$ with broad Mg II or H$\beta$ emission…

Astrophysics of Galaxies · Physics 2020-09-30 Fan Zou , William N. Brandt , Fabio Vito , Chien-Ting Chen , Gordon P. Garmire , Daniel Stern , Ashraf Ayubinia

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…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-02 Michael Rowan-Robinson , Ivan Valtchanov , Kirpal Nandra

The Chandra Deep Field is the region of the sky with the highest concentration of X-ray data available: 4Ms of Chandra and 3Ms of XMM data, allowing excellent quality spectra to be extracted even for faint sources. We take advantage of this…

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…

We examine the 24 micron to X-ray color of 157 X-ray--selected AGN as a function of X-ray obscuration and optical classification in the Chandra Deep Field South. The sample consists of the Chandra hard--band detections with hard flux…

(abridged) We identify a numerically significant population of heavily obscured AGNs at z~0.5-1 in the Chandra Deep Field-South (CDF-S) and Extended Chandra Deep Field-South by selecting 242 X-ray undetected objects with infrared-based star…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 B. Luo , W. N. Brandt , Y. Q. Xue , D. M. Alexander , M. Brusa , F. E. Bauer , A. Comastri , A. C. Fabian , R. Gilli , B. D. Lehmer , D. A. Rafferty , D. P. Schneider , C. Vignali
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