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In this paper we cross-correlate the FIRST 1.4GHz radio survey with a wide field (~ 1.6deg^2) shallow [f(0.5-8keV) ~ 1e-14erg/s/cm^2] XMM-Newton survey. We find 12 X-ray/radio matches representing 4% of the X-ray selected sample. Most of…

Astrophysics · Physics 2009-11-10 A. Georgakakis , I. Georgantopoulos , I. Leonidaki , Akylas , G. C. Stewart , C. Goudis

We present CCD observations of 13 objects from a complete sample of 55 bright High Frequency Peaker (HFP) radio sources, and provide optical identification for 12 of them. Images in R and V filters have been used to derive some additional…

Astrophysics · Physics 2009-11-07 D. Dallacasa , R. Falomo , C. Stanghellini

We report the results of a volume-limited survey using the Australia Telescope Compact Array to search for transient and quiescent radio emission from 15 southern hemisphere ultracool dwarfs. We detect radio emission from 2MASSW…

Solar and Stellar Astrophysics · Physics 2016-01-11 C. Lynch , T. Murphy , V. Ravi , G. Hobbs , K. Lo , C. Ward

We present deep radio observations of the most distant complete quasar sample drawn from the Sloan Digital Sky Survey. Combining our new data with those from literature we obtain a sample which is ~100 per cent complete down to S_1.4GHz =…

Astrophysics · Physics 2009-11-11 M. Cirasuolo , M. Magliocchetti , G. Gentile , A. Celotti , S. Cristiani , L. Danese

The third iteration of the International Celestial Reference Frame (ICRF3) is made up of 4536 quasars observed at S/X bands using Very Long baseline Interferometry (VLBI). These sources are high redshift quasars, typically between $1<z<2$,…

Astrophysics of Galaxies · Physics 2021-09-08 Lucas R. Hunt , Megan C. Johnson , Phillip J. Cigan , David Gordon , John Spitzak

Recent broad-band 34 and 44 GHz radio continuum observations of the Galactic center have revealed 41 massive stars identified with near-IR counterparts, as well as 44 proplyd candidates within 30" of Sgr A*. Radio observations obtained in…

Astrophysics of Galaxies · Physics 2015-08-19 F. Yusef-Zadeh , H. Bushouse , R. Schödel , M. Wardle , W. Cotton , D. A. Roberts , F. Nogueras-Lara , E. Gallego-Cano

Recent studies of the cosmic X-ray background (XRB) have suggested the possible existence of a population of relatively faint sources with hard X-ray spectra; however, the emission mechanism remains unclear. If the hard X-ray emission is…

Astrophysics · Physics 2007-05-23 Insu Yi , Stephen P. Boughn

We report new Chandra observations of seven optically faint, z \sim 4 radio-quiet quasars. We have combined these new observations with previous Chandra observations of radio-quiet quasars to create a sample of 174 sources. These sources…

Using the Spitzer Space Telescope, we have obtained rest frame 9-16mu spectra of 11 quasars and 9 radio galaxies from the 3CRR catalog at redshifts 1.0<z<1.4. This complete flux-limited 178MHz-selected sample is unbiased with respect to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 C. Leipski , M. Haas , S. P. Willner , M. L. N. Ashby , B. J. Wilkes , G. G. Fazio , R. Antonucci , P. Barthel , R. Chini , P. Ogle , R. Siebenmorgen , F. Heymann

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

Radio and X-ray emission of AGN appears to be correlated. The details of the underlying physical processes, however, are still not fully understood, i.e., to what extent is the X-ray and radio emission originating from the same relativistic…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-05 Jens Zuther , Sebastian Fischer , Andreas Eckart

In this paper we use a 50ks XMM-Newton pointing overlapping with the Phoenix Deep Survey, a homogeneous radio survey reaching muJy sensitivities, to explore the X-ray properties and the evolution of star-forming galaxies. UV, optical and…

This paper reports the X-ray spectral analysis of 5 high-redshift (z \ge 2) radio-quiet quasars observed by ASCA. A simple power law continuum plus cold Galactic absorption model well fits all the spectra (tipically between $\sim$ 2-30 keV…

Astrophysics · Physics 2009-10-31 C. Vignali , A. Comastri , M. Cappi , G. G. C. Palumbo , M. Matsuoka , H. Kubo

We present observations of six late-type members of the young cluster IC 348 detected at 24 microns with the Multiband Imaging Photometer for Spitzer(MIPS). At least four of the objects are probably substellar. Combining these data with…

The results of a deep 20 cm radio survey at 20 cm are reported of the AKARI Deep Field South (ADF-S) near the South Ecliptic Pole (SEP), using the Australia Telescope Compact Array telescope, ATCA. The survey has 1 sigma detection limits…

Galaxy source counts in the infrared provide strong constraints on the evolution of the bolometric energy output from distant galaxy populations. We present the results from deep 24 micron imaging from Spitzer surveys, which include…

Powered by supermassive black holes at their centers, quasars are among the most luminous objects in the Universe, serving as important probes of cosmic history and galaxy evolution. The size of the accretion disc surrounding the black hole…

Astrophysics of Galaxies · Physics 2025-08-04 F. Pozo Nuñez , E. Bañados , S. Panda , J. Heidt

Simultaneous multiwavelength studies of X-ray binaries have been remarkably successful and resulted in improved physical constraints, a new understanding of the dependence of mass accretion rate on X-ray state, as well as insights on the…

Astrophysics · Physics 2009-06-23 Saeqa D. Vrtilek

We report results on a 40 ks XMM-Newton observation of the Type 2 quasar 3C 234. Optical spectropolarimetric data have demonstrated the presence of a hidden broad-line region in this powerful (M_V <~ -24.2 after reddening and starlight…

Astrophysics · Physics 2009-11-13 E. Piconcelli , S. Bianchi , G. Miniutti , F. Fiore , M. Guainazzi , E. Jimenez-Bailon , G. Matt

High-redshift radio-loud quasars are used to, among other things, test the predictions of cosmological models, set constraints on black hole growth in the early universe and understand galaxy evolution. Prior to this paper, 20 extragalactic…