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Related papers: Unifying B2 radio galaxies with BL Lac objects

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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

Many properties of BL Lacs have become explicable in terms of the "relativistic beaming" hypothesis whereby BL Lacs are FR-1 radio galaxies viewed nearly along the jet axis. However, a possible problem with this model is that a transition…

Astrophysics · Physics 2009-10-31 Travis A. Rector , John T. Stocke , Eric S. Perlman

We explain the properties of X-ray selected BL Lacertae objects, under the assumption that they constitute the small minority of the BL Lac population with energy cutoff located in the UV/X-ray band, as suggested by their multifrequency…

Astrophysics · Physics 2009-10-22 Paolo Padovani , Paolo Giommi

We present a new well defined sample of BL Lac objects selected from the ROSAT All-Sky Survey (RASS). The sample consists of 39 objects with 35 forming a flux limited sample down to f_X = 8 x 10^{-13} cgs, redshifts are known for 33 objects…

Astrophysics · Physics 2007-05-23 N. Bade , V. Beckmann , N. G. Douglas , P. D. Barthel , D. Engels , L. Cordis , P. Nass , W. Voges

We present an analysis of X-ray data, taken with ROSAT, for a well defined sample of low-power radio galaxies from the Bologna B2 catalogue. Where possible, the HRI has been used in order to take advantage of the higher spatial resolution…

Astrophysics · Physics 2009-10-31 C. M. Canosa , D. M. Worrall , M. J. Hardcastle , M. Birkinshaw

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 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

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

This paper presents a new sample of BL Lac objects selected from a deep (30 mJy) radio survey of flat spectrum radio sources (the CLASS blazar survey, henceforth CBS). The sample is one of the largest well defined samples in the low power…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 M. J. M. Marcha , A. Caccianiga

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 discuss alternative interpretations of the differences in the Spectral Energy Distributions (SEDs) of BL Lacs found in complete Radio or X-ray surveys. A large body of observations in different bands suggests that the SEDs of BL Lac…

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

BL Lac objects are an extreme type of active galactic nuclei (AGNs) that belong to the largest population of $\gamma$-ray sources: blazars. This class of AGNs shows a double-bumped spectral energy distribution that is commonly described in…

High Energy Astrophysical Phenomena · Physics 2020-04-08 E. J. Marchesini , A. Paggi , F. Massaro , N. Masetti , R. D'Abrusco , I. Andruchow , R. de Menezes

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

We present the scientific goals, the strategy and the first results of the REX project, an effort aimed at creating a sizable and statistically complete sample of Radio Emitting X-ray sources (REX) using the available data from a VLA survey…

Astrophysics · Physics 2009-10-31 A. Caccianiga , T. Maccacaro , A. Wolter , R. Della Ceca , I. M. Gioia

We present the soft X-ray (0.1--2.4 keV) properties of a complete sample of 88 southern radio sources derived from the Wall \& Peacock 2-Jy sample. It comprises 68 radio galaxies, 18 quasars and 2 BL Lac objects. Whereas both BL Lac objects…

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 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 present updated and complete radio, optical and X-ray data for BL Lacs in the Einstein Medium Sensitivity Survey (EMSS). The complete "M91" sample first presented in Morris et al. is updated to include 26 BL Lacs in total and we define a…

Astrophysics · Physics 2009-10-31 T. A. Rector , J. T. Stocke , E. S. Perlman , S. L. Morris , I. M. Gioia

We present new optical and near-IR spectroscopy as well as new high dynamic range, arcsecond-resolution VLA radio maps of BL Lacs from the complete radio-selected "1 Jansky" (1Jy) sample (RBLs) for which such data were not previously…

Astrophysics · Physics 2009-11-06 Travis A. Rector , John T. Stocke
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