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Tracking the star formation rate to high redshifts requires knowledge of the contribution from both optically visible and obscured sources. The dusty, optically-obscured galaxies can be located by X-ray and infrared surveys. To establish…

Astrophysics · Physics 2009-11-10 D. Weedman , V. Charmandaris , A. Zezas

In order to examine the far-IR/radio correlation at high redshift we have studied the Spitzer 70um/far-infrared (far-IR) properties of sub-mJy radio sources from the 13^H XMM-Newton/Chandra Deep Field by redshift and galaxy type: active…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 N. Seymour , M. Huynh , T. Dwelly , M. Symeonidis , A. Hopkins , I. M. McHardy , M. Page , G. Rieke

Luminous radio sources are thought to lie in galaxy clusters or proto-clusters. The complete sample of 64 high-redshift 3C sources at $1<z<2.5$ has been mapped with the Spitzer Space Telescope. The IRAC $3.6\mu$m and $4.5\mu$m 5-$\sigma$…

Astrophysics of Galaxies · Physics 2017-10-09 Z. Ghaffari , Ch. Westhues , M. Haas , R. Chini , S. P. Willner , M. L. N. Ashby , B. J. Wilkes

With recent Chandra observations, at least 60% of the 2-10 keV background is now resolved into discrete sources. Here we present deep optical, NIR, submm, and 20 cm (radio) images, as well as high-quality optical spectra, of a complete…

Astrophysics · Physics 2009-09-25 A. J. Barger , L. L. Cowie , R. F. Mushotzky , E. A. Richards

We present the results of 5-GHz observations with the VLA A-array of a sample of candidate Compact Steep Spectrum sources (CSSs) selected from the S4 survey. We also estimate the symmetry parameters of high-luminosity CSSs selected from…

Astrophysics · Physics 2009-10-31 D. J. Saikia , S. Jeyakumar , C. J. Salter , P. Thomasson , R. E. Spencer , F. Mantovani

We present a Chandra observation of the powerful radio galaxy 3C294 showing clear evidence for a surrounding intracluster medium. At a redshift of 1.786 this is the most distant cluster of galaxies yet detected in X-rays. The radio core is…

Astrophysics · Physics 2009-11-06 A. C. Fabian , C. S. Crawford , S. Ettori , J. S. Sanders

Some luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) host extremely compact and dusty nuclei. The intense infrared radiation arising from warm dust in these sources is prone to excite vibrational levels of molecules such as…

We study the spectral energy distributions and evolution of a large sample of optically selected quasars from the Sloan Digital Sky Survey (SDSS) that were observed in 323 Chandra images analyzed by the Chandra Multiwavelength Project…

We present a large robust sample of 1503 reliable and unconfused 70microm selected sources from the multiwavelength data set of the Cosmic Evolution Survey (COSMOS). Using the Spitzer IRAC and MIPS photometry, we estimate the total infrared…

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…

We present a small sample of Chandra X-ray sources selected from the fields of ACIS observations which probe fluxes around the break in the hard band source counts. The targets of these fields include 9 nearby galaxy clusters, 1 distant…

Astrophysics · Physics 2009-09-17 P. Gandhi , C. S. Crawford , A. C. Fabian , R. M. Johnstone

We present the results of a programme of thermal-IR imaging of nineteen z~1 radio galaxies from the 3CR and 3CRR samples. We detect emission at L' (3.8um) from four objects; in each case the emission is unresolved at 1" resolution. Fifteen…

Astrophysics · Physics 2009-10-31 Chris Simpson , Steve Rawlings , Mark Lacy

We report first X-ray Chandra observations of a sample of seven low luminosity compact (LLC) sources. They belong to a class of young compact steep spectrum (CSS) radio sources. Four of them have been detected, the other three have upper…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 M. Kunert-Bajraszewska , A. Labiano , A. Siemiginowska , M. Guainazzi

We present a detailed and self-consistent modeling of the cosmic X-ray background (XRB) based on the most up-to-date X-ray luminosity functions (XLF) and evolution of Active Galactic Nuclei (AGN). The large body of observational results…

Astrophysics · Physics 2009-11-11 Roberto Gilli , Andrea Comastri , Guenther Hasinger

We present new Chandra observations that complete a sample of seventeen (17) luminous infrared galaxies (LIRGs) with D < 60 Mpc and low Galactic column densities of N_H < 5 X 10^20 cm^-2. The LIRGs in our sample have total infrared…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-19 B. D. Lehmer , D. M. Alexander , F. E. Bauer , W. N. Brandt , A. D. Goulding , L. P. Jenkins , A. Ptak , T. P. Roberts

We present 6-GHz Very Large Array radio images of 70 gravitational lens systems at 300-mas resolution, in which the source is an optically-selected quasar, and nearly all of which have two lensed images. We find that about in half of the…

Astrophysics of Galaxies · Physics 2024-04-05 Neal Jackson , Shruti Badole , Thomas Dugdale , Hannah R. Stacey , Philippa Hartley , J. P. McKean , .

We study the cluster environment for a sample of 21 radio loud AGN from the 3CR catalog at z>1, 12 radio galaxies and 9 quasars with HST images in the optical and IR. We use two different approaches to determine cluster candidates. We…

In this paper, the third and final of a series, we present complete K-band imaging and some complementary I-band imaging of the filtered 6C* sample. We find no systematic differences between the K-z relation of 6C* radio galaxies and those…

We report the results from a {\it Chandra} observation of the powerful nearby (z=0.1744) radio galaxy 3C 219. We find evidence for non--thermal X-ray emission from the radio lobes which fits fairly well with a combination of IC scattering…

Astrophysics · Physics 2007-05-23 G. Brunetti , A. Comastri , D. Dallacasa , M. Bondi , M. Pedani , G. Setti

We present a comprehensive analysis of Chandra X-ray observations of 15 young radio quasars at redshifts $4.5 < z < 5.0$. All sources are detected in the $0.5-7.0$ keV energy band. Emission spectra are extracted, and the average photon…