Ultra high energy cosmic ray events presently show a spectrum, which we
interpret here as galactic cosmic rays due to a starburst in the radio galaxy
Cen A pushed up in energy by the shock of a relativistic jet. The knee feature
and the particles with energy immediately higher in galactic cosmic rays then
turn into the bulk of ultra high energy cosmic rays. This entails that all
ultra high energy cosmic rays are heavy nuclei. This picture is viable if the
majority of the observed ultra high energy events come from the radio galaxy
Cen A, and are scattered by intergalactic magnetic fields across most of the
sky.Comment: 4 pages, 1 figure, proceedings of "High-Energy Gamma-rays and
  Neutrinos from Extra-Galactic Sources", Heidelber

A. MELI

Gergely L.

Ginzburg V. L.

I. C. MARIŞ

J. K. BECKER

Junkes N.

L. CARAMETE

L. GERGELY

P. L. BIERMANN

Ryu D.

Stanev T.

T. STANEV

V. DE SOUZA

English

arXiv

Ultra high energy cosmic ray events presently show a spectrum, which we interpret here as galactic cosmic rays due to a starburst, in the radio galaxy Cen A which is pushed up in energy by the shock of a relativistic jet. The knee feature and the particles with energy immediately higher in galactic cosmic rays then turn into the bulk of ultra high energy cosmic rays. This entails that all ultra high energy cosmic rays are heavy nuclei. This picture is viable if the majority of the observed ultra high energy events come from the radio galaxy Cen A, and are scattered by intergalactic magnetic fields across much of the sky

BIERMANN, P. L.

BECKER, J. K.

CARAMETE, L.

GERGELY, L.

MARIS, I. C.

MELI, A.

Souza, Vitor de

STANEV, T.

Universidade de São Paulo

International Journal of Modern Physics D

Active galactic nuclei: sources for ultra high energy cosmic rays

Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)

Ultra high energy cosmic ray events presently show a spectrum, 
which we interpret here as galactic cosmic rays due to a 
starburst, in the radio galaxy Cen A which is pushed up in 
energy by the shock of a relativistic jet. The knee feature and 
the particles with energy immediately higher in galactic cosmic 
rays then turn into the bulk of ultra high energy cosmic rays. 
This entails that all ultra high energy cosmic rays are heavy 
nuclei. This picture is viable if the majority of the observed 
ultra high energy events come from the radio galaxy Cen A, and 
are scattered by intergalactic magnetic fields across much of 
the sky. © 2009 World Scientific Publishing Company

PL, Biermann

JK, Becker

L, Caramete

LÁ, Gergely

IC, Mariş

A, Meli

V, de Souza

T, Stanev

ELTE Digital Institutional Repository (EDIT)

arXiv:0904.1507v2  [astro-ph.HE]  10 Apr 2009October 22, 2018 1:48 BiermannetalACTIVE GALACTIC NUCLEI WITH STARBURSTS: SOURCESFOR ULTRA HIGH ENERGY COSMIC RAYSP.L. Biermann1∗, J.K. Becker2†, L. Caramete3, L.Á. Gergely4, I.C. Mariş5, A. Meli6,V. de Souza7, T. Stanev81MPI for Radioastronomy, D-53121 Bonn, Germany (www.mpifr-bonn.mpg.de/div/theory),2Institution för Fysik, Göteborgs Univ., Sweden, 3Institute for Space Sciences, Bucharest,Romania, 4Phys. Dept., Univ. of Szeged, Szeged, Hungary, 5Inst. Nucl. Phys. FZ, KarlsruheInst. of Techn. (KIT), Germany, 6Erlangen Center for Astroparticle Physics, Univ.Erlangen-Nürnberg, Germany, 7Universidade de São Paulo, Instituto de F́ısica de São Carlos,Brazil, 8Bartol Research Inst., Univ. of Delaware, Newark, DE, USAUltra high energy cosmic ray events presently show a spectrum, which we interpret hereas galactic cosmic rays due to a starburst in the radio galaxy Cen A pushed up inenergy by the shock of a relativistic jet. The knee feature and the particles with energyimmediately higher in galactic cosmic rays then turn into the bulk of ultra high energycosmic rays. This entails that all ultra high energy cosmic rays are heavy nuclei. Thispicture is viable if the majority of the observed ultra high energy events come from theradio galaxy Cen A, and are scattered by intergalactic magnetic fields across most of thesky.Keywords: Ultra high energy cosmic rays; Active Galactic Nuclei; Intergalactic magneticfields.1. IntroductionThe origin of ultra high energy cosmic ray has been a riddle since their discovery1963 by Linsley (Ref. 1). After many experiments and measurements we are begin-ning to accumulate reasonable statistics with the Auger array, and have a very goodspectrum, shown in our figure below (see Ref. 2).As there is a weak correlation with active galactic nuclei, various classes of suchobjects have come under consideration again. Radio galaxies have been argued tobe sources for some time (see Ref. 3), but none in our cosmic neighborhood readilyaccelerates protons to such high energy, as derived from the jet energetics (seeRef. 4). Heavy nuclei seem to be required. Here we outline such a scenario (seeRef. 5), and give a spectral fit in the figure below.∗Also at Univ. of Bonn, Univ. of Alabama, Tuscaloosa, AL, Univ. of Alabama at Huntsville, andat KIT Karlsruhe†also at the University of Dortmund, and from June 2009 also at the University of Bochum1October 22, 2018 1:48 Biermannetal2 P.L. Biermann, J.K. Becker, L. Caramete, L.Á. Gergely, I.C. Mariş, A. Meli, V. de Souza, T. Stanev2. Starburst and relativistic jetWhen two galaxies merge (see Ref. 6), we first have a starburst, and second acentral activity that outshines the young stars, and also disperses much of theinterstellar material. Usually such a merger is also accompanied by a spinflip of themore massive black hole, due to the dominant relative orbital spin, when two blackholes merge. This implies that a new jet forms and bores a new channel throughthe environment, freshly filled with galactic cosmic rays. These new galactic cosmicrays have a relatively flat spectrum to the bend, commonly referred to as the knee,where the spectrum turns down. Gallant & Achterberg (Ref. 7) have shown thatthe shock in a single interaction pushes the particle energies up by Γ2j , where Γj isthe the Lorentz factor of the shock. Studies of radio interferometry and other workhas suggested that in the spine of the jet this Lorentz factor can reach 50. Thereforethe spectral distribution near the knee (see Ref. 8) may be pushed up in energy bya factor up to 2500. This then clearly provides ultra high energy particles. The onlysource in our cosmic neighborhood capable of doing this is the radio galaxy Cen A.Obviously, we do need scattering by magnetic fields (see Ref. 9, 10, 11) to explaina spectrum built from events all over the sky, but coming from a single source. Infact, since their MHD cosmological simulations already give some large angle scat-tering for protons, and we here argue for heavy nuclei, those models would producean almost perfectly isotropic sky. However, as shown by inconsistencies in the mag-netic field determinations in our Galaxy (see Ref. 12), the medium is probablyhighly filamentary, strongly reducing the angular scattering. This is reasonable forhighly super-Alfvénic turbulence injected by super-nova explosions. In the inter-galactic medium super-Alfvénic turbulence may be due to radio galaxies. Thus thescattering may be moderate even for heavy nuclei, explaining the large scale nearlyisotropic sky distribution, but also allowing many events to come from directionsclose to Cen A.3. The spectrumWe have taken the spectrum for galactic cosmic rays (Ref. 8), pushed it up tomatch the turnoff feature near 40 EeV and fitted it to the Auger data, as published(Ref. 2). We match the slope below the Fe-edge at 40 EeV, the step down, andthe slope beyond 40 EeV. Obviously it is possible to improve the match, and sowe tested modifying the abundances; we note that the abundances of the variouschemical elements in the winds of Wolf-Rayet stars and Red Super Giant starsdepend on the initial abundances, but most of all on the zero age masses of thestars, and so on their mass distribution: Therefore it cannot a priori be expected,that the abundances in cosmic rays in our Galaxy match those in another galaxy. Adecrease by 20 percent the abundances of the two element groups Ne-S and Cl-Mnimproves the match below 40 EeV to near perfect. Due to the small distance of theradio galaxy Cen A, we do not expect any strong effect from propagation; however,since some particles are required in our model to make detours, that clearly isOctober 22, 2018 1:48 BiermannetalUltra high energy cosmic rays 3another simplification. We show the match without taking any of this into account(Ref. 2, 8):Fig. 1. Testing the spectrum in paper CR-IV with Auger data, with all six element groupsunmodified.Taken literally, this interpretation of the data suggests that beyond 40 EeV thetwo dominant element groups are Ne - S and Iron, all coming from Cen A.4. Discussion, conclusions and predictionsAs interactions of photons with heavy nuclei give very much lower fluxes of highenergy photons and neutrinos, we wonder, whether this argument would not reducethe high energy neutrino fluxes to below any possible detection limit (Ref. 13). Onthe other hand, we note that we expect high energy neutrinos from flat spectrumradio sources, which have their current relativistic jet pointed at the Observer onEarth. All such sources are highly variable, and so also the interactions may runright into saturation for many flares, producing very high neutrino fluxes, but for avery short time.If there are any protons among the ultra high energy particles, they should pointbetter towards their sources; very few events point to the radio galaxy Cen A (note,that Cen A extends 10 degrees on the sky: Ref. 14). Those that do appear to comeOctober 22, 2018 1:48 Biermannetal4 P.L. Biermann, J.K. Becker, L. Caramete, L.Á. Gergely, I.C. Mariş, A. Meli, V. de Souza, T. Stanevfrom inside the radio source extent cannot be protons and also be attributed to CenA, since Cen A cannot give so high energies to protons, by the Poynting flux limit(see Ref. 4) and using its jet power (Ref. 15; this is also true, if protons initiallyaccelerated get converted to neutrons that decay back to protons (Ref. 16).This model predicts: a) ultra high energy cosmic rays are mostly the elementsNe - S and Iron; b) most of events come from the radio galaxy Cen A; and c) wedo need highly filamentary magnetic structures in the intergalactic medium whichscatter to large angles without completely isotropizing the paths of the events.Further statistics should confirm spectrum, scattering distribution, and chemicalcomposition.AcknowledgmentsSupport for work with PLB has come from the AUGER membership and theorygrant 05 CU 5PD 1/2 via DESY/BMBF and VIHKOS. Support for JKB comes fromthe DFG grant BE-3714/3-1 and from the IceCube grant BMBF (05 A08PE1). V.de Souza is supported by FAPESP (2008/04259-0). Support for TS comes fromDOE grand UD-FG02-91ER40626.References1. Linsley, J., Phys. Rev. Letters 10, 146 - 148 (1963)2. Auger-Coll., Phys. Rev. Letters 101, ms. 061101 (2008)3. V. L. Ginzburg & S. I. Syrovatskii, Astron. Zh. 40 (1963) 466 - 476 ; transl. in Sov.Astron. A.J. 7 (1963) 357 - 3644. R.V.E. Lovelace, Nature 262 (1976) 6495. P. L. Biermann et al., in proc. CRIS2008, Malfa, Salina Island, Italy, Ed. A. Insolia,(2008) in press; arXiv: 0811.1848v36. L. Gergely & P.L. Biermann, in press Astrophys. J. (2009); arXiv:0805.45827. Y.-A. Gallant, & A. Achterberg, Month. Not. Roy. Astr. Soc. 305 (1999) L6 - L108. T. Stanev, P.L. Biermann & T.K. Gaisser, Astron. & Astroph. 274 (1993) 902 ;astro-ph/9303006 (CR-IV)9. D. Ryu, H. Kang & P.L. Biermann, Astron. & Astroph. 335 (1998) 19 - 25;astro-ph/980327510. D. Ryu et al., 2008 Science 320 (2008) 90911. S. Das et al., Astrophys. J. 682 (2008) 29 - 3812. R. Beck et al. Astron. & Astroph. 411 (2003) 99 - 10713. J. K. Becker & P. L. Biermann, Astropart. Phys. 31 (2009) 138; arXiv:0805.149814. Junkes, N., et al. Astron. & Astroph. 269 (1993) 29 - 38; erratum: Astron. & Astroph.274 (1993) 100915. Whysong, D., Antonucci, R., New Astron. Rev. 47 (2003) 219 - 22316. Rachen, J.P., XXth Rencontres de Blois, ”Challenges in Particle Astrophysics”,arXiv:0808.0349 (2008)

Active Galactic Nuclei with Starburst: Sources for Ultra High Energy Cosmic Rays

Crossref

ACTIVE GALACTIC NUCLEI: SOURCES FOR ULTRA HIGH ENERGY COSMIC RAYS

Ultra high energy cosmic ray events presently show a spectrum, which we interpret here as galactic cosmic rays due to a starburst, in the radio galaxy Cen A which is pushed up in energy by the shock of a relativistic jet. The knee feature and the particles with energy immediately higher in galactic cosmic rays then turn into the bulk of ultra high energy cosmic rays. This entails that all ultra high energy cosmic rays are heavy nuclei. This picture is viable if the majority of the observed ultra high energy events come from the radio galaxy Cen A, and are scattered by intergalactic magnetic fields across much of the sky. © 2009 World Scientific Publishing Company.SCOPUS: cp.jinfo:eu-repo/semantics/publishe

Biermann, Peter P.L.

Becker, Julia J.K.

Caramete, Laurent¸iu Ioan L.

Gergely, László Árpád L.

Maris, Ioana Codrina

Meli, Athina

De Souza, Vitor

Stanev, Todor

DI-fusion

Active galactic nuclei: Sources for ultra high energy cosmic rays

RCAAP - Repositório Científico de Acesso Aberto de Portugal