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We have carried out a deep search at 1.4 GHz for radio pulsed emission from six soft X-ray transient sources observed during their X-ray quiescent phase. The commonly accepted model for the formation of the millisecond radio pulsars…

Astrophysics · Physics 2008-11-26 M. Burgay , L. Burderi , A. Possenti , N. D'Amico , R. N. Manchester , A. G. Lyne , F. Camilo

A sample of high-frequency peaker (HFP) candidates was formed from the AT20G catalog radio sources with spectral indices of the optically thick emission region $\alpha_{below}$ exceeding +0.5. A study of the spectral properties of the…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-12 Elena Majorova , Olga Zhelenkova

Our VLA observations of the XMM-Newton/Chandra 13hr deep survey field (see Page et al., this proceedings) result in one of the two deepest 1.4GHz radio maps ever made. Within the 15' radius field covered by the deep X-ray data (0.19 sq…

Determining the star-forming properties of radio-quiet quasars is important for understanding the co-evolution of star formation and black hole accretion. Here, we present the detection of the gravitationally-lensed radio-quiet quasars SDSS…

We have assembled a sample of 37 RLQs that have been imaged with the HST in order to investigate their black hole masses, accretion rates, and the structure of their accretion disks. The black hole masses were estimated from the…

Astrophysics · Physics 2009-11-10 Jian-Min Wang , Luis C. Ho , Ruediger Staubert

Recently, Zakamska et al. (2003) selected 291 high-ionization narrow emission-line AGN in the redshift range 0.3-0.83 from the Sloan Digital Sky Survey spectroscopic data. The sample includes both Seyfert II galaxies and their higher…

Astrophysics · Physics 2009-11-10 C. Vignali , D. M. Alexander , A. Comastri

We present the first broad-band X-ray study of the nuclei of 14 hard X-ray selected giant radio galaxies, based both on the literature and on the analysis of archival X-ray data from NuSTAR, XMM-Newton, Swift and INTEGRAL. The X-ray…

High Energy Astrophysical Phenomena · Physics 2018-09-26 F. Ursini , L. Bassani , F. Panessa , A. J. Bird , G. Bruni , M. Fiocchi , A. Malizia , L. Saripalli , P. Ubertini

Recent works have suggested that selection criteria based on MIR colors can be used to reveal a population of dust-enshrouded, extremely luminous quasars at z>1. However the X-ray spectral properties of these intriguing sources still remain…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 G. Lanzuisi , E. Piconcelli , F. Fiore , C. Feruglio , C. Vignali , M. Salvato , C. Gruppioni

We examine the disc--jet connection in stellar mass and supermassive black holes by investigating the properties of their compact emission in the X-ray and radio bands. We compile a sample of ~100 active galactic nuclei with measured mass,…

Astrophysics · Physics 2011-05-05 Andrea Merloni , Sebastian Heinz , Tiziana Di Matteo

We have conducted a pilot survey for z>3.5 quasars by combining the FIRST radio survey with the SDSS. While SDSS already targets FIRST sources for spectroscopy as quasar candidates, our survey includes fainter quasars and greatly improves…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Ian D. McGreer , David J. Helfand , Richard L. White

We report the detection of steady radio emission from the known X-ray source X9 in the globular cluster 47 Tuc. With a double-peaked C IV emission line in its ultraviolet spectrum providing a clear signature of accretion, this source had…

We report the results of 20, 6, and 2 cm VLA and 1.5 cm OVRO observations of the optically-selected CfA Seyfert galaxies and the bolometric-flux-limited 12-Micron active galaxy sample. Every object observed was detected at 6 cm. Only 6-8%…

Astrophysics · Physics 2009-10-28 Brian Rush , Matthew A. Malkan , Richard A. Edelson

Supernova (SN) rates serve as an important probe of star-formation models and initial mass functions. Near-infrared seeing-limited ground-based surveys typically discover a factor of 3-10 fewer SNe than predicted from far-infrared (FIR)…

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 results on a search of heavily obscured active galaxies z>1.7 using the rest-frame 9-20 keV excess for X-ray sources detected in the deep XMM-CDFS survey. Out of 176 sources selected with the conservative detection criteria (>8…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 K. Iwasawa , R. Gilli , C. Vignali , A. Comastri , W. N. Brandt , P. Ranalli , F. Vito , N. Cappelluti , F. J. Carrera , S. Falocco , I. Georgantopoulos , V. Mainieri , M. Paolillo

We have compiled and analysed reports from the literature of (quasi-)simultaneous observations of X-ray transients at radio and X-ray wavelengths and compared them with each other and with more unusual radio-bright sources such as Cygnus…

Astrophysics · Physics 2009-11-06 R. P. Fender , E. Kuulkers

In this work, we investigated the X-ray emission for a sample of young radio AGNs by combining their data from Chandra/XMM-Newton and at other wavebands. We find strong correlations between the X-ray luminosity $L_{\rm X}$ in 2$-$10 keV and…

Astrophysics of Galaxies · Physics 2020-06-10 Mai Liao , Minfeng Gu , Minhua Zhou , Liang Chen

We present the radio and X-ray properties of 1.2 mm MAMBO source candidates in a 1600 sq. arcmin field centered on the Abell 2125 galaxy cluster at z=0.247. The brightest, non-synchrotron mm source candidate in the field has a photometric…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-24 Jeff Wagg , Frazer Owen , Frank Bertoldi , Maike Sawitzki , Christopher L. Carilli , Karl M. Menten , Hauke Voss

This paper presents the analysis of a statistically complete sample of 28 serendipitous X-ray sources selected in 82 pointed XMM-Newton fields down to a count-rate of 0.002 counts s^-1(4.5-7.5 keV energy band). This is the first sample…

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