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相关论文: The properties of powerful radio sources at 90 GHz

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Radio galaxies with jets of relativistic particles are usually hosted by massive elliptical galaxies with active nuclei powered by accretion of interstellar matter onto a supermassive black hole. In some rare cases (<5%), their jets drive…

星系天体物理 · 物理学 2020-11-11 Pratik Dabhade , Francoise Combes , Philippe Salome , Joydeep Bagchi , Mousumi Mahato

A complete sample of 27 radio galaxies was selected from the B2 and 3CR catalogs, in order to study their properties on the milliarcsecond scale. In the Appendix of this paper we present new radio images for 12 of them. Thanks to the…

天体物理学 · 物理学 2009-11-06 G. Giovannini , W. D. Cotton , L. Feretti , L. Lara , T. Venturi

Among radio galaxies, compact sources are a class of objects not yet well understood, and most of them cannot be included in classical populations of compact radio sources (flat spectrum AGN or compact steep spectrum sources). Our main goal…

宇宙学与河外天体物理 · 物理学 2015-06-11 E. Liuzzo , S. Buttiglione , G. Giovannini , M. Giroletti , S. Capetti , G. B. Taylor

We present multi-frequency radio observations of a sample of z~2 obscured (type-2) quasars in the Spitzer extragalactic First Look Survey area. We combine the public data at 1.4 GHz, used in the selection of these sources, with new…

We present radio spectra spanning $0.1 - 10$ GHz for the sample of heavily obscured luminous quasars with extremely red mid-infrared-optical colors and compact radio emission. The spectra are constructed from targeted 10 GHz observations…

We present optical identifications and redshifts for seventeen new high-redshift radio sources. Fifteen of these sources are radio galaxies; the remaining two are high-redshift, steep-spectrum, radio-loud quasars. These objects were…

We have assembled an 8.4 GHz survey of bright, flat-spectrum (alpha > -0.5) radio sources with nearly uniform extragalactic (|b|>10 deg) coverage for sources brighter than S_{4.8 GHz} = 65 mJy. The catalog is assembled from existing…

Observational studies of GHz peaked spectrum (GPS) sources contribute to the understanding of the radiative properties and interstellar environment of host galaxies. We present the results from the multi-frequency high-resolution VLBI…

高能天体物理现象 · 物理学 2023-03-07 Xiaopeng Cheng , Tao An , Ailing Wang , Sumit Jaiswal

According to radiative models, radio galaxies and quasars are predicted to produce gamma rays from the earliest stages of their evolution. Exploring their high-energy emission is crucial for providing information on the most energetic…

Multi-frequency radio observations of the radio bridge of powerful classical double radio sources can be used to determine: the beam power of the jets emanating from the AGN; the total time the source will actively produce jets that power…

天体物理学 · 物理学 2015-05-27 Lin Wan , Ruth A. Daly , Erick J. Guerra

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…

星系天体物理 · 物理学 2024-04-05 Neal Jackson , Shruti Badole , Thomas Dugdale , Hannah R. Stacey , Philippa Hartley , J. P. McKean , .

We present a study of the peculiar radio galaxy B 1834+620. It is characterised by the presence of a 420-kpc large edge-brightened radio source which is situated within, and well aligned with, a larger (1.66 Mpc) radio source. Both sources…

天体物理学 · 物理学 2009-10-31 Arno P. Schoenmakers , A. G. de Bruyn , H. J. A. Rottgering , H. van der Laan

Here we discuss evolution and broad-band emission of compact (< kpc) lobes in young radio sources. We propose a simple dynamical description for these objects, consisting of a relativistic jet propagating into a uniform gaseous medium in…

天体物理学 · 物理学 2009-11-13 L. Stawarz , L. Ostorero , M. C. Begelman , R. Moderski , J. Kataoka , S. Wagner

Deep radio observations of a wide region centred on the Hubble Deep Field South have been performed, providing one of the most sensitive set of radio observations acquired on the Australia Telescope Compact Array to date. A central rms of…

天体物理学 · 物理学 2008-11-26 Minh T. Huynh , Carole A. Jackson , Ray P. Norris

A sample of 123 radio sources that exhibit significant variations at 1.4 GHz on a seven year base-line has been created using FIRST VLA B-array data from 1995 and 2002 on a strip at dec=0 near the south Galactic cap. This sample spans the…

天体物理学 · 物理学 2009-11-10 W. H. de Vries , R. H. Becker , R. L. White , D. J. Helfand

Several binary systems consisting of a massive star and a compact object have been detected above 100 GeV in the Galaxy. In most of these sources, gamma-rays show a modulation associated to the orbital motion, which means that the emitter…

高能天体物理现象 · 物理学 2015-05-18 V. Bosch-Ramon

We used the Australia Telescope Compact Array (ATCA) to obtain 40 GHz and 95 GHz observations of a number of sources that were selected from the Australia Telescope Compact Array 20 GHz (AT20G) survey . The aim of the observations was to…

星系天体物理 · 物理学 2015-05-19 Paul J. Hancock , Elaine M. Sadler , Elizabeth K. Mahony , Roberto Ricci

It is currently accepted that intrinsically compact and bright radio sources characterized by a convex spectrum peaking at frequencies ranging from 100 MHz to a few GHz are young objects. Following the evolutionary models, these objects…

宇宙学与河外天体物理 · 物理学 2010-12-02 M. Orienti , D. Dallacasa

We present an analysis of the spectral properties of the extragalactic radio sources in the nearly-complete VSA sample at 33GHz. Data from different surveys are used to study source spectra between 1.4 and 33GHz. We find that, in general,…

Pairs of radio emitting jets with lengths up to several hundred kiloparsecs emanate from the central region (the `core') of radio loud active galaxies. In the most powerful of them, these jets terminate in the `hotspots', compact high…

天体物理学 · 物理学 2016-08-30 Markos Georganopoulos , Demosthenes Kazanas