Active galactic nuclei — the physics of individual sources and the cosmic history of formation and evolution

Krawczynski, H.; Treister, Ezequiel

doi:10.1007/s11467-013-0310-3

Cited by 17 publications

(14 citation statements)

References 183 publications

(246 reference statements)

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“…From geometrical considerations of the jet inclination angles with respect to the line of sight, we expect that for each active galactic nucleus (AGN) whose jet is pointed within a small angle of our line of sight (blazars; e.g. Urry 1999;Krawczynski & Treister 2013), there should be hundreds 1 of sources with jets pointing elsewhere (Volonteri et al 2011). In Volonteri et al (2011), the authors compare the number of high-redshift radio-loud sources in the Sloan Digital Sky Survey (SDSS) and Very Large Array (VLA) Faint Images of the Radio Sky at Twenty-centimeter (FIRST) survey (White et al 1997) with the number of blazars between z = 1 and z = 6 and find that they are consistent at z < 3 but disagree at z > 3.…”

Section: Introductionmentioning

confidence: 99%

On the nature of bright compact radio sources atz> 4.5

Coppejans¹,

Frey²,

Cseh³

et al. 2016

Mon. Not. R. Astron. Soc.

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High-redshift radio-loud quasars are used to, among other things, test the predictions of cosmological models, set constraints on black hole growth in the early universe and understand galaxy evolution. Prior to this paper, 20 extragalactic radio sources at redshifts above 4.5 have been imaged with very long baseline interferometry (VLBI). Here we report on observations of an additional ten z > 4.5 sources at 1.7 and 5 GHz with the European VLBI Network (EVN), thereby increasing the number of imaged sources by 50 per cent. Combining our newly observed sources with those from the literature, we create a substantial sample of 30 z > 4.5 VLBI sources, allowing us to study the nature of these objects. Using spectral indices, variability and brightness temperatures, we conclude that of the 27 sources with sufficient information to classify, the radio emission from one source is from star formation, 13 are flat-spectrum radio quasars and 13 are steep-spectrum sources. We also argue that the steep-spectrum sources are off-axis (unbeamed) radio sources with rest-frame self-absorption peaks at or below GHz frequencies and that these sources can be classified as gigahertz peaked-spectrum (GPS) and megahertz peaked-spectrum (MPS) sources.

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Section: Introductionmentioning

confidence: 99%

On the nature of bright compact radio sources atz> 4.5

Coppejans¹,

Frey²,

Cseh³

et al. 2016

Mon. Not. R. Astron. Soc.

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“…It includes active galactic nuclei (AGNs, H. Krawczynski and E. Treister) [1] that host super-massive black holes, stellar-size black hole X-ray binaries (BHXBs, S.-N. Zhang) [2], gamma-ray bursts (GRBs, N. Gehrels and S. Razzaque) [3], and various species in the neutron star (NS) zoo (A. K. Harding) [4]. The 5th planned article on supernovae and their remnants did not materialize.…”

Section: Pacs Numbersmentioning

confidence: 99%

“…[1], Krawzynski and Treister review the astrophysics of AGNs, the nuclei of galaxies that host supermassive black holes in the mass range 10 6 -10 10 M , which accrete materials from the environment. In some cases, these accreting BHs launch a pair of powerful jets.…”

Section: Pacs Numbersmentioning

confidence: 99%

Preface: High energy astrophysics

Zhang

Mésáros

2013

Front. Phys.

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High energy astrophysics is one of the most active branches in the contemporary astrophysics. It studies astrophysical objects that emit X-ray and γ-ray photons, such as accreting super-massive and stellar-size black holes, and various species of neutron stars. With the operations of many space-borne and ground-based observational facilities, high energy astrophysics has enjoyed rapid development in the past decades. It is foreseen that the field will continue to advance rapidly in the coming decade, with possible ground-breaking discoveries of astrophysical sources in the high-energy neutrino and gravitational wave channels. This Special Issue of Frontiers of Physics is dedicated to a systematic survey of the field of high energy astrophysics as it stands in 2013. 95.85.Nv, 95.85.Pw, 95.85.Ry, 95.85.Sz, 97.60.Lf, 97.60.Jd, 97.80.Jp, 98.62.Js High energy astrophysics is the branch of astrophysics that studies astrophysical objects that emit high energy photons (X-rays and γ-rays), and more generally, emit non-thermal photons outside the traditional optical wavelengths. By studying non-thermal emission in the universe, one can unveil the part of universe that is not in a steady state, usually originating in violent environments near compact objects, such as neutron stars and black holes of different scales. These objects, besides emitting the broad-band non-thermal electromagnetic radiation, are also believed to be emitters of other signals outside the electromagnetic channel. These multi-messenger signals include cosmic rays, neutrinos, and gravitational waves. The field of high energy astrophysics, along with cosmology and planetary sciences, is one of the three most active branches in the contemporary astrophysics. PACS numbersDuring the past decades, the field of high energy astrophysics has enjoyed a rapid development, thanks to an impressive list of space-borne and ground-based observational facilities. The currently operating space missions dedicated to high energy astrophysics include the Chandra X-ray Observatory, the X-ray Multi-Mirror Mission (XMM)-Newton, Suzaku, and the Nuclear

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“…One of the parameters kept constant in the previous studies is the total jet luminosity L, which we now vary. We performed a number of test calculations to compute the lower and upper limits of L that produce a spectrum qualitatively similar to that of the source Mrk 421 (Krawczynski & Treister 2013). In the Table 1 we show the range of variations of this and other parameters.…”

Section: Parameter Studymentioning

confidence: 99%

On the influence of a hybrid thermal–non-thermal distribution in the internal shocks model for blazars

Rueda-Becerril¹,

Mimica²,

Aloy³

2017

Monthly Notices of the Royal Astronomical Society

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Internal shocks occurring in blazars may accelerate both thermal and non-thermal electrons. In this paper we examine the consequences that such a hybrid (thermal/non-thermal) EED has on the spectrum of blazars. Since the thermal component of the EED may extend to very low energies. We replace the standard synchrotron process by the more general magnetobremsstrahlung (MBS). Significant differences in the energy flux appear at low radio frequencies when considering MBS instead of the standard synchrotron emission. A drop in the spectrum appears in the all the radio band and a prominent valley between the infrared and soft X-rays bands when a hybrid EED is considered, instead of a power-law EED. In the γ-ray band an EED of mostly thermal particles displays significant differences with respect to the one dominated by non-thermal particles. A thermally-dominated EED produces a synchrotron self-Compton (SSC) peak extending only up to a few MeV, and the valley separating the MBS and the SSC peaks is much deeper than if the EED is dominated by non-thermal particles. The combination of these effects modifies the Compton dominance of a blazar, suggesting that the vertical scatter in the distribution of FSRQs and BL Lac objects in the peak synchrotron frequency -Compton dominance parameter space could be attributed to different proportions of thermal/non-thermal particles in the EED of blazars. Finally, the temperature of the electrons in the shocked plasma is shown to be a degenerated quantity for different magentizations of the ejected material.

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Active galactic nuclei — the physics of individual sources and the cosmic history of formation and evolution

Cited by 17 publications

References 183 publications

On the nature of bright compact radio sources atz> 4.5

On the nature of bright compact radio sources atz> 4.5

Preface: High energy astrophysics

On the influence of a hybrid thermal–non-thermal distribution in the internal shocks model for blazars

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