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Related papers: BL Lac evolution revisited

200 papers

Using three complete, radio flux limited, blazar samples we compare the LogN-LogS and the preliminary radio luminosity function of the general population of BL Lacs to those of the subclass of high energy synchrotron peaked (HBL) BL Lacs.…

Astrophysics · Physics 2007-05-23 P. Giommi , P. Padovani , M. Perri , H. Landt , E. Perlman

Host galaxies of Active Galactic Nuclei give crucial information on the interaction between accreting Supermassive Black Holes and their surroundings, and on their common evolution. Their study in the case of aligned jetted AGN - BL…

High Energy Astrophysical Phenomena · Physics 2026-03-18 Gaia Delucchi , Tullia Sbarrato , Giorgio Calderone , Chiara Righi , Silvano Tosi , Boris Sbarufatti

We study the cosmological evolution of BL Lac objects by applying the Ve/Va analysis to a new sample of 55 objects presented for the first time in this paper. This sample has been selected from the 239 sources with the brightest X-ray flux…

Astrophysics · Physics 2009-11-07 A. Caccianiga , T. Maccacaro , A. Wolter , R. Della Ceca , I. M. Gioia

The BL Lac population is set apart from the rest of the active galactic nuclei by a number of peculiar features, including remarkably little signs of cosmological evolution. We focus on this feature, and take hint from the observations to…

Astrophysics · Physics 2009-10-31 A. Cavaliere , D. Malquori

We propose a scenario where blazars are classified as flat-spectrum radio quasars (FSRQs), BL Lacs, low synchrotron, or high synchrotron peaked objects according to a varying mix of the Doppler boosted radiation from the jet, the emission…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 P. Giommi , P. Padovani , G. Polenta , S. Turriziani , V. D'Elia , S. Piranomonte

Recent VLBI studies of the morphology and kinematics of individual BL Lac objects (S5 1803+784, PKS 0735+178, etc.) have revealed a new paradigm for the pc-scale jet kinematics of these sources. Unlike the apparent superluminal outward…

Cosmology and Nongalactic Astrophysics · Physics 2012-01-18 Marios Karouzos , Silke Britzen , Arno Witzel , Anton J. Zensus , Andreas Eckart

We use highly spectroscopically complete deep and wide-area Chandra surveys to determine the cosmic evolution of hard X-ray-selected AGNs. We determine hard X-ray luminosity functions (HXLFs) for all spectral types and for broad-line AGNs…

Astrophysics · Physics 2008-11-26 A. J. Barger , L. L. Cowie , R. F. Mushotzky , Y. Yang , W. -H. Wang , A. T. Steffen , P. Capak

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

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

We present a large sample of 501 radio-selected BL Lac candidates from the combination of the Sloan Digital Sky Survey (SDSS) Data Release 5 optical spectroscopy and from the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) radio…

Low luminosity active galactic nuclei (LLAGN) probe accretion physics in the low Eddington regime and can provide additional clues about galaxy evolution. AGN variability is ubiquitous and thus provides a reliable tool for finding AGN. We…

The advent of Fermi is changing our understanding on the radio and gamma-ray emission in Active Galactic Nuclei. In fact, contrary to previous campaigns, Fermi mission reveals that BL Lac objects are the most abundant emitters in gamma-ray…

High Energy Astrophysical Phenomena · Physics 2013-06-05 E. Liuzzo , B. Boccardi , M. Giroletti , G. Giovannini

Detection of Gamma-ray emission from a class of active galactic nuclei (viz blazars), has been one of the important findings from the Compton Gamma Ray Observatory (CGRO). However, their Gamma-ray luminosity function has not been well…

Astrophysics · Physics 2009-12-17 D. Bhattacharya , P. Sreekumar , R. Mukherjee

The discovery of changing-look active galactic nuclei (CL AGNs), with appearance and disappearance of broad emission lines and/or with strong variation of line-of-sight column density within a few years, challenges the AGN unification…

Astrophysics of Galaxies · Physics 2019-12-10 Hao liu , Qingwen Wu , Bing Lyu , Zhen Yan

We put forward a scenario where blazars are classified as flat-spectrum radio quasars, BL Lacs, low synchrotron, or high synchrotron peaked objects according to a varying combination of Doppler boosted radiation from the jet, emission from…

High Energy Astrophysical Phenomena · Physics 2012-05-04 P. Padovani , P. Giommi , G. Polenta , S. Turriziani , V. D'Elia , S. Piranomonte

Active Galactic Nuclei (AGN) have long been known to be variable, but the amplitude, timescale and nature of these changes can often differ dramatically from object to object. The richest source of information about the properties of AGN…

Astrophysics of Galaxies · Physics 2021-07-14 Hartmut Winkler

This paper presents a detailed analysis of the radio properties for the sample of faint radio sources introduced in Magliocchetti et al. (2000). The sample comprises mainly intrinsically low-power sources whose majority ($\simgt 70$ per…

Astrophysics · Physics 2009-11-07 M. Magliocchetti , A. Celotti , L. Danese

I describe two difficulties with current research into the cosmic evolution of BL Lacertae Objects: (1). Possible sample incompleteness due to unrecognized (i.e., ``hidden'') BL Lacs; and (2). The absence of a viable physical model of the…

Astrophysics · Physics 2007-05-23 John T. Stocke

Detailed VLA observations have been gathered for a number of sources classified as either BL Lacs or galaxies, derived from the REX survey. We focus in particular on the sources identified by us, for which we have in hand homogeneous…

Astrophysics · Physics 2007-05-23 Anna Wolter , A. Caccianiga , T. Maccacaro , R. Della Ceca , I. M. Gioia , F. Cavallotti , M. Minoia

The evolutionary role of the so-called ``changing-look'' (CL) active galactic nucleus (AGN), which is characterized by spectral-type transitions within $\sim10$ yr, has been suggested in the past few years. By focusing on CL-AGNs having…

Astrophysics of Galaxies · Physics 2026-03-24 J. Wang , S. Jin , D. W. Xu , WeiKang Zheng , Thomas G. Brink , S. Komossa , 1 Alexei V. Filippenko , J. Y. Wei