Centaurus A as a source of extragalactic cosmic rays with arrival energies well beyond the GZK cutoff

Romero, Gustavo E.; Combi, J. A.; Bergliaffa, Santiago Esteban Pérez; Anchordoqui, Luis A.

doi:10.1016/0927-6505(96)00029-1

Cited by 79 publications

(80 citation statements)

References 17 publications

(24 reference statements)

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“…Cen A as a possible source of UHE cosmic rays was early proposed by (Romero et al 1996). Recently, the Pierre Auger Collaboration reported the existence of anisotropy on the arrival directions of UHE cosmic rays (Abraham et al 2007), remarking that at least 2 of this events can be correlated with the Cen A position (3 • circle).…”

Section: Cen Amentioning

confidence: 99%

“…If neutrons of the same energy are produced by pion photoproduction inside the jet, these could been beamed along the jet and decay into protons near the outer radio lobes, where they would be re-accelerated up to the observed energies by Auger. Other possibilities were proposed by Rieger & Aharonian (2009), with particles that go through shear acceleration inside the jet, and by Romero et al (1996), who considered that the UHE cosmic rays are produced at the extended radio lobes. If this is the case, it has been estimated by Hardcastle et al (2009) that the minimum jet power required is roughly L (kin) j > 3.5 × 10 43 erg s −1 , which is consistent with the value assumed here.…”

Section: Application To Centaurus Amentioning

confidence: 99%

“…In hadronic models, interactions of highly relativistic protons in the jet with ambient matter and photon fields, protoninduced cascades, or synchrotron radiation of protons, are responsible for the high-energy photons (see e.g. Mücke et al 2000;Mücke & Protheroe 2001;Reimer et al 2004;Costamante et al 2008;Hardcastle et al 2009;Romero et al 1996;Orellana & Romero 2009). There also exist models which are not based on the emission of accelerated particles in the relativistic jet and assume the production of TeV γ-rays in a pulsar-like cascade mechanism in the magnetosphere of the black hole (e.g.…”

Section: Introductionmentioning

confidence: 99%

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A lepto-hadronic model for high-energy emission from FR I radiogalaxies

Reynoso

Medina

Romero

2011

A&A

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Context. The well known radiogalaxy Cen A has been recently detected as a source of very high energy (VHE) γ-rays by the HESS experiment just before Fermi/LAT detected it at high energies (HE). The detection, together with that of M 87, established radiogalaxies as VHE γ-ray emitters. Aims. The aim of this work is to present a lepto-hadronic model for the VHE emission from the relativistic jets in FR I radiogalaxies. Methods. We consider that protons and electrons are accelerated in a compact region near the base of the jet, and they cool emitting multi wavelength radiation as propagating along the jet. The proton and electron distributions are obtained through steady-state transport equation taking into account acceleration, radiative and non-radiative cooling processes, as well as particle transport by convection. Results. Considering the effects of photon absorption at different wavelengths, we calculate the radiation emitted by the primary protons and electrons, as well as the contribution of secondaries particles (e ± , πs and μs). The expected high-energy neutrino signal is also obtained and the possibility of detections with KM3NeT and IceCube is discussed. Conclusions. The spectral energy distribution obtained in our model with an appropriate set of parameters for an extended emission zone can account for much of the observed spectra for both AGNs.

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Section: Cen Amentioning

confidence: 99%

Section: Application To Centaurus Amentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A lepto-hadronic model for high-energy emission from FR I radiogalaxies

Reynoso

Medina

Romero

2011

A&A

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“…However, in certain regions where measurements at both high and low resolution are available, the B-field amplitude at high resolution can be seen to be twice that at low resolution. The higher resolution can reveal amplification in the post-shock region [237], yielding B-fields possibly as high as 50 − 60 µG [238,239]. The radio-visible size of the hot spot can be directly measured from the large scale map [240], giving R HS ≃ 2 kpc.…”

Section: Radiogalaxiesmentioning

confidence: 99%

Astrophysical origins of ultrahigh energy cosmic rays

2004

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In the first part of this review we discuss the basic observational features at the end of the cosmic ray energy spectrum. We also present there the main characteristics of each of the experiments involved in the detection of these particles. We then briefly discuss the status of the chemical composition and the distribution of arrival directions of cosmic rays. After that, we examine the energy losses during propagation, introducing the Greisen-Zaptsepin-Kuzmin (GZK) cutoff, and discuss the level of confidence with which each experiment have detected particles beyond the GZK energy limit. In the second part of the review, we discuss astrophysical environments able to accelerate particles up to such high energies, including active galactic nuclei, large scale galactic wind termination shocks, relativistic jets and hot-spots of Fanaroff-Riley radiogalaxies, pulsars, magnetars, quasar remnants, starbursts, colliding galaxies, and gamma ray burst fireballs. In the third part of the review we provide a brief summary of scenarios which try to explain the super-GZK events with the help of new physics beyond the standard model. In the last section, we give an overview on neutrino telescopes and existing limits on the energy spectrum and discuss some of the prospects for a new (multi-particle) astronomy. Finally, we outline how extraterrestrial neutrino fluxes can be used to probe new physics beyond the electroweak scale. Solicited Review Article Prepared for Reports on Progress in Physics 1 PREFACEReviewing cosmic ray physics is a risky business. Theoretical models continue to appear at an amazing rate, both in the astrophysical and more exotic domains. We warn the reader: we do not (nor we could) intend to make an homogeneous coverage of all the ideas of our fellow colleagues. Reading differently focused reviews on the issue (quoted here along the way) is, in our view, the best approach to such a wide topic of research.2 Contents

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“…That they originate in nearby radiogalaxies and BL Lacs has long been predicted (Rachen & Biermann 1993;Romero et al 1996). More exotic explanations include dark matter anhilation and the evaporation of micro black holes.…”

Section: Introductionmentioning

confidence: 99%

Ultra-high energy cosmic rays detected by Auger and AGASA

Nagar

Matulich

2010

A&A

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Context. The origin and composition of ultra-high energy cosmic rays (UHECRs) remain unclear. Possible sources include active galactic nuclei -selected by various criteria -and extragalactic magnetars. Aims. We aim to improve constraints on the source population(s) and compositions of UHECRs by accounting for UHECR deflections within existing Galactic magnetic field models (GMFs). Methods. We used Monte Carlo simulations for UHECRs detected by the Pierre Auger Observatory and AGASA, to determine the UHECR trajectories within the Galaxy and their outside-the-Galaxy arrival directions. The simulations, which used UHECR compositions from protons to iron and seven models of the ordered GMF, accounted for uncertainties in the GMF and a turbulent magnetic field component. Trajectories and outside-the-Galaxy arrival directions were compared with Galactic and extragalactic sources. Results. For a given proton or light UHECR, the multiple potential outside-the-Galaxy arrival directions within a given GMF model are not very different, allowing meaningful constraints on source populations. Our previous claim of a correlation between a subset of UHECRs and nearby extended radiogalaxies remains valid, even strengthened, within several GMF models. Both the nearest radiogalaxy Cen A, and the nearest radio-extended BL Lac, CGCG 413−019, are potential sources of multiple UHECRs. The correlation appears to be linked to the extended radio source rather than a tracer of an underlying matter distribution. Several UHECRs have trajectories that pass close to the Galactic plane, some passing close to Galactic magnetars and/or microquasars. For heavier UHECRs, the multiple potential outside-the-Galaxy arrival directions of any given UHECR are highly scattered but still allow meaningful constraints. It is possible, but unlikely, that all UHECRs originate in the nearby radiogalaxy Cen A. Conclusions. Nearby radiogalaxies remain a strong potential source of a significant subset of UHECRs. For light UHECRs, about a third of UHECRs can be "matched" to nearby galaxies with extended radio jets. The remaining UHECRs could also be explained as originating in extended radiogalaxies if one has at least one of: a large UHECR mean free path, a high cluster and/or intergalactic magnetic field, and a heavy composition for two-thirds of the detected UHECRs. If extended radiogalaxies are, or trace, UHECR sources, the most consistent models for the ordered GMF are the BS-S and BS-A models; the GMF models of Sun and collaborators are acceptable if a dipole component is added.

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Centaurus A as a source of extragalactic cosmic rays with arrival energies well beyond the GZK cutoff

Cited by 79 publications

References 17 publications

A lepto-hadronic model for high-energy emission from FR I radiogalaxies

A lepto-hadronic model for high-energy emission from FR I radiogalaxies

Astrophysical origins of ultrahigh energy cosmic rays

Ultra-high energy cosmic rays detected by Auger and AGASA

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