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Related papers: Unification of BL Lac objects, FR I and FR II(G) r…

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We collect multi-wavelength measurements of the nuclear emission of 20 low luminosity FR I radio-galaxies to test the viability of the FR I - BL Lac unifying model. Although poorly sampled, the Spectral Energy Distributions (SED) of FR Is…

Astrophysics · Physics 2009-11-07 E. Trussoni , A. Capetti , A. Celotti , M. Chiaberge , L. Feretti

We explore the viability of the unification of BL Lacs and FR I radio galaxies by comparing the core emission of radio galaxies with those of BL Lacs, taking advantage of the newly measured optical nuclear luminosity of FR I sources. The…

Astrophysics · Physics 2007-05-23 Marco Chiaberge , Annalisa Celotti , Alessandro Capetti , Gabriele Ghisellini

We explore the viability of the unification of BL Lacs and FR I radio galaxies by comparing the core emission of radio galaxies with those of BL Lacs of similar extended radio power, taking advantage of the newly measured optical nuclear…

Astrophysics · Physics 2007-05-23 Marco Chiaberge , Annalisa Celotti , Alessandro Capetti , Gabriele Ghisellini

Our knowledge of Giga-electron volt (GeV) radio galaxies has been revolutionized by the Fermi-LAT Telescope, which provides an excellent opportunity to study the physical properties of GeV radio galaxies. According to the radio power and…

High Energy Astrophysical Phenomena · Physics 2023-05-18 Xu-Hong Ye , Xiang-Tao Zeng , Dan-Yi Huang , Zhuang Zhang , Zhi-Yuan Pei , Jun-Hui Fan

In this paper, we collect radio and X-ray observations for most Fanaroff-Riley I (FRI) radio galaxies in the Zirbel-Baum radio galaxy sample, and investigate the distribution of the radio-to-X-ray effective spectral index, $\alpha_{rx}$, to…

Astrophysics · Physics 2009-10-31 J. M. Bai , Myung Gyoon Lee

In this paper: 1. The assumption of the dependence of Doppler factor on the emission frequency (Fan et al. 1993) is used to explain the observational differences between the radio-selected BL Lac objects(RBLs) and the X-Ray-Selected BL Lac…

Astrophysics · Physics 2016-08-30 J. H. Fan

Hubble Space Telescope (HST) observations provide a novel way of testing unified models for FR I radio sources and BL Lac objects. The detection of extended dust discs in some radio galaxies provides information on their jet orientation.…

Astrophysics · Physics 2009-10-31 Alessandro Capetti , Annalisa Celotti

Two key results are presented in this paper. First, equipartition Doppler factors have been estimated for a sample of 105 sources with previously estimated inverse Compton Doppler factors. The different categories of active galactic nuclei…

Astrophysics · Physics 2008-02-03 R. A. Daly , E. J. Guerra , A. Guijosa

In an earlier paper we presented nuclear X-ray flux densities, measured with ROSAT, for the B2 bright sample of nearby low-luminosity radio galaxies. In this paper we construct a nuclear X-ray luminosity function for the B2 radio galaxies,…

Astrophysics · Physics 2009-11-07 M. J. Hardcastle , D. M. Worrall , M. Birkinshaw , C. M. Canosa

We investigate the environments of galaxies around BL Lac objects and FR I radiogalaxies, the alleged parent populations of misaligned sources. We compare the environment of a sample of 50 BL Lac objects at 0.1<z<0.33 with that of a sample…

High Energy Astrophysical Phenomena · Physics 2019-04-10 A. Sandrinelli , R. Falomo , A. Treves

We present new radio data completing the imaging for a sample of 30 nearby (z < 0.2) BL Lac objects on parsec and kiloparsec scale. The sample is composed of both high and low luminosity sources and it is therefore an ideal test bed for…

Astrophysics · Physics 2007-05-23 M. Giroletti , G. Giovannini , G. B. Taylor , R. Falomo

We examine the optical properties of the nuclei of low luminosity radio-galaxies using snapshot HST images of the B2 sample. In agreement with the results obtained from the analysis of the brighter 3C/FRI sample, we find a correlation…

Astrophysics · Physics 2009-11-07 A. Capetti , A. Celotti , M. Chiaberge , H. R. de Ruiter , R. Fanti , R. Morganti , P. Parma

We present a morphological and spectral study of a sample of 99 BL Lacs using the LOFAR Two-Metre Sky Survey Second Data Release (LDR2). Extended emission has been identified at gigahertz frequencies around BL Lacs, but with LDR2 it is now…

We have recently proposed a new scenario where blazars are classified as flat-spectrum radio quasars or BL Lacs according to the prescriptions of unified schemes, and to a varying combination of Doppler boosted radiation from the jet,…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-11 Paolo Giommi , Paolo Padovani

In a companion paper we presented a statistical model for the blazar population, consisting of distributions for the unbeamed radio luminosity function and the Lorentz factor distribution of each of the BL Lac and Flat Spectrum Radio Quasar…

High Energy Astrophysical Phenomena · Physics 2015-10-21 I. Liodakis , V. Pavlidou

We present deep radio images at 1.4 GHz of a large and complete sample of BL Lacertae objects (BL Lacs) selected from the Deep X-ray Radio Blazar Survey (DXRBS). We have observed 24 northern sources with the Very Large Array (VLA) in both…

Astrophysics · Physics 2009-11-13 Hermine Landt , Hayley E. Bignall

...The distribution of radio core-dominance is consistent with average projection angles of 13.5, 14.8, 16.8, 20.4, and 28.2 for ISPs, LSPs, FSRQs, HSPs, and radio galaxies, respectively. Linear regression analyses of our data yield…

Astrophysics of Galaxies · Physics 2021-04-28 E. U. Iyida , F. C. Odo , A. E. Chukwude

The phenomenology of gamma-ray bright blazars can be accounted for by a sequence in the source power and intensity of the diffuse radiation field surrounding the relativistic jet. Correspondingly, the equilibrium particle distribution peaks…

Astrophysics · Physics 2009-10-30 G. Ghisellini , A. Celotti , G. Fossati , L. Maraschi , A. Comastri

Our understanding of the unification of jetted AGNs has advanced greatly as the size of extragalactic sources increased. In the present paper, based on the large sample of radio sources, we compiled 680 blazars (279 FSRQs and 401 BL Lacs)…

Astrophysics of Galaxies · Physics 2021-11-17 E. U. Iyida , I. O. Eya , F. C. Odo

Statistical analyses are invaluable methods used to understand intrinsic emission processes and the unification of extragalactic radio sources. In this paper, we collected radio, X-ray and {\gamma}-ray data of blazars from the Fermi-LAT and…

High Energy Astrophysical Phenomena · Physics 2021-12-08 E. U. Iyida , I. O. Eya , F. C. Odo
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