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Related papers: A multi-wavelength test of the FR~I - BL Lac unify…

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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

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

In this work, we collected a sample of BL Lacs, FR I and FR II(G) radio galaxies with available core and extended emissions from published works to discuss the unified schemes and estimate the Doppler factor for BL Lacs. Wilcoxon rank-sum…

Astrophysics of Galaxies · Physics 2021-11-18 Xu-Hong Ye , Jun-Hui Fan

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

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

We consider archival ROSAT and HST observations of five FRI radio galaxies and isolate their nuclear emission from that of the host galaxy. This enable us to determine the Spectral Energy Distributions (SED) of their nuclei spanning from…

Astrophysics · Physics 2009-10-31 A. Capetti , E. Trussoni , A. Celotti , L. Feretti , M. Chiaberge

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

We investigate the physical properties of BL Lac objects (BL Lacs) jets by modeling the quasi-simultaneous spectral energy distributions (SEDs) of 22 {\it Fermi} BL Lac objects in the frame of a simple one-zone synchrotron self-Compton…

High Energy Astrophysical Phenomena · Physics 2014-03-05 Dahai Yan , Houdun Zeng , Li Zhang

We address the question of whether or not the properties of all low-luminosity flat spectrum radio sources, not just the obvious BL Lac objects, are consistent with them being the relativistically beamed counterparts of the low radio…

Astrophysics · Physics 2009-11-11 M. J. M. Marchã , I. W. A. Browne , N. Jethava , S. Antón

We compile a sample of spectral energy distribution (SED) of 12 GeV radio galaxies (RGs), including eight FR I RGs and four FR II RGs. These SEDs can be represented with the one-zone leptonic model. No significant unification as expected in…

High Energy Astrophysical Phenomena · Physics 2017-09-20 Zi-Wei Xue , Jin Zhang , Wei Cui , En-Wei Liang , Shuang-Nan Zhang

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 determine the nuclear spectral energy distribution (SED) from the radio to the gamma-ray band for the FR I radio galaxy NGC6251, by using both data from the literature and analyzing HST and X-ray archival data. In the Log nu - Log nu…

Astrophysics · Physics 2009-11-10 Marco Chiaberge , Roberto Gilli , Alessandro Capetti , F. Duccio Macchetto

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 collect data from the radio to the gamma-ray range for three complete samples of blazars: the Slew Survey and the 1Jy samples of BL Lacs and the 2Jy sample of Flat Spectrum Radio-Loud Quasars (FSRQs). The fraction of objects detected in…

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

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

We propose a new physical model for the unification of all Blazars. The blazar phenomenology can be accounted for by a sequence in the source power and intensity of the diffuse radiation field surrounding the relativistic jet. This…

Astrophysics · Physics 2007-05-23 G. Fossati

We estimate the intrinsic luminosities and synchrotron peak frequency using the derived Doppler factor for a sample of 170 BL Lac objects, of which the synchrotron peak frequency are derived by fitting the SED constructed with the collected…

Astrophysics · Physics 2009-11-13 Zhongzu Wu , Minfeng Gu , D. R. Jiang

In a previous paper, we proposed a new method to select low-power BL Lacs (LPBLs) based on mid-infrared emission and flux contrast through the Ca II spectral break; that study led to the selection of a complete sample formed by 34 LPBLs…

Astrophysics of Galaxies · Physics 2016-02-17 Claudia M. Raiteri , Alessandro Capetti

We discuss alternative interpretations of the differences in the Spectral Energy Distributions (SEDs) of BL Lacs found in complete Radio or X--ray surveys. In order to explain the different properties of radio and X-ray selected within the…

Astrophysics · Physics 2007-05-23 G. Fossati , A. Celotti , G. Ghisellini , L. Maraschi

We present a new sample of 30 nearby (z<0.2) BL Lacs, selected to study the nuclear as well as the large scale properties of low power radio sources. In this first paper, we show and discuss new radio data taken with the VLA (19 objects at…

Astrophysics · Physics 2009-11-10 M. Giroletti , G. Giovannini , G. B. Taylor , R. Falomo
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