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200 papers

Recent analysis of the distribution of clusters of galaxies is reviewed. Clusters of galaxies located in rich superclusters form a quasiregular lattice. The mean power spectrum of galaxies and clusters has been found, it has a peak at…

Astrophysics · Physics 2007-05-23 Jaan Einasto

We report the first large, systematic study of the dynamics and energetics of a representative sample of FRII radio galaxies with well-characterized group/cluster environments. We used X-ray inverse-Compton and radio synchrotron…

Astrophysics of Galaxies · Physics 2017-02-01 Judith Ineson , Judith H. Croston , Martin J. Hardcastle , Beatriz Mingo

We describe very accurate imaging of radio spectral index for the inner jets in three FR I radio galaxies. Where the jets first brighten, there is a remarkably small dispersion around a spectral index of 0.62. This is also the region where…

Astrophysics · Physics 2008-01-03 R. A. Laing , A. H. Bridle , W. D. Cotton , D. M. Worrall , M. Birkinshaw

We report the most important results on the parsec-scale properties of a complete sample of radio galaxies carried out at radio frequencies with the Global VLBI array and with the VLBA. Relativistic parsec-scale jets are common both in FRI…

Astrophysics · Physics 2007-05-23 T. Venturi , G. Giovannini , L. Feretti , W. D. Cotton , L. Lara

We present a model for the inverted radio spectra of active active galactic nuclei as well as the central regions of normal galaxies. The model is based on the unified scenario for active galaxies, stating that the central engines of active…

Astrophysics · Physics 2007-05-23 M. Boettcher , H. -P. Reuter , H. Lesch

Radio relic sources in galaxy clusters are often described as the remnants of powerful radio galaxies. Here we develop a model for the evolution of such relics after the jets cease to supply energy to the lobes. This includes the treatment…

Astrophysics · Physics 2009-11-07 Christian R. Kaiser , Garret Cotter

We built a catalog of 122 FR~II radio galaxies, called FRII{\sl{CAT}}, selected from a published sample obtained by combining observations from the NVSS, FIRST, and SDSS surveys. The catalog includes sources with redshift $\leq 0.15$, an…

High Energy Astrophysical Phenomena · Physics 2017-05-10 A. Capetti , F. Massaro , R. D. Baldi

Powerful radio galaxies exist as either compact or extended sources, with the extended sources traditionally classified by their radio morphologies as Fanaroff--Riley (FR) type I and II sources. FRI/II and compact radio galaxies have also…

Astrophysics of Galaxies · Physics 2017-04-26 H. Miraghaei , P. N. Best

We have measured the angular correlation function of radio sources in the 1.4 GHz NVSS and FIRST surveys. Below ~6 arcminutes w(theta) is dominated by the size distribution of radio galaxies. A model of the size distribution of radio…

Astrophysics · Physics 2009-11-07 R. A. Overzier , H. J. A. Rottgering , R. B. Rengelink , R. J. Wilman

The shape of low-frequency radio continuum spectra of normal galaxies is not well understood, the key question being the role of physical processes such as thermal absorption in shaping them. In this work we take advantage of the LOFAR…

Current wide-area radio surveys are dominated by active galactic nuclei, yet many of these sources have no identified optical counterparts. Here we investigate whether one can constrain the nature and properties of these sources, using…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Sjoert van Velzen , Heino Falcke , Elmar Koerding

The F-GAMMA program is among the most comprehensive programs that aim at understanding the physics in active galactic nuclei through the multi-frequency monitoring of Fermi blazars. Here we discuss monthly sampled broad-band radio spectra…

We have observed 28 local galaxies in the wavelength range between 1 and 2.4 mic in order to define template spectra of the normal galaxies along the Hubble sequence. Five galaxies per morphological type were observed in most cases, and the…

Astrophysics · Physics 2010-04-06 F. Mannucci , F. Basile , B. M. Poggianti , A. Cimatti , E. Daddi , L. Pozzetti , L. Vanzi

We estimate ages and physical properties of powerful radio galaxies. An analysis of new multi-wavelength VLA observations of eleven very powerful classical double (FRIIb) radio galaxies with redshifts between 0.4 and 1.3 is presented. We…

We present an analytical model for the cosmological evolution of the FRII source population. Based on an earlier model for the intrinsic radio luminosity - linear size evolution of these objects, we construct theoretical source samples. The…

Astrophysics · Physics 2009-10-30 Christian R. Kaiser , Paul Alexander

In classifying the ensemble of powerful extragalactic radio sources, considerable evidence has accumulated that radio galaxies and quasars are orientation-dependent manifestations of the same parent population: massive spheroidal galaxies…

The F-GAMMA program is a coordinated effort to investigate the physics of Active Galactic Nuclei (AGNs) via multi-frequency monitoring of Fermi blazars. In the current study we show and discuss the evolution of broad-band radio spectra,…

Spectral index images can be used to constraint the energy spectrum of relativistic electrons and magnetic field distribution in radio halos and relics, providing useful information to understand their formation, evolution and connection to…

Astrophysics · Physics 2009-11-13 E. Orru' , M. Murgia , L. Feretti , F. Govoni , G. Brunetti , G. Giovannini , M. Girardi , G. Setti , .

We examine the radiation spectra from relativistic electrons moving in a Langmuir turbulence expected to exist in high energy astrophysical objects by using numerical method. The spectral shape is characterized by the spatial scale…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Yuto Teraki , Fumio Takahara

We explore the properties of the large-scale environment of FR0 radio galaxies belonging to the FR0CAT sample which includes 104 compact radio sources associated with nearby (z<0.05) early-type galaxies. By using various estimators we find…

Astrophysics of Galaxies · Physics 2020-09-09 Alessandro Capetti , Francesco Massaro , Ranieri D. Baldi