Particle Acceleration and Curvature TeV Emission by Rotating, Supermassive Black Holes

Levinson, Amir

doi:10.1103/physrevlett.85.912

Cited by 120 publications

(152 citation statements)

References 25 publications

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“…The compact dynamo model has been proposed as a natural mechanism for accelerating cosmic rays in dead quasars (Boldt & Ghosh 1999;Levinson 2000;Boldt & Loewenstein 2000). Only 0.2% of dead quasars are required to contribute to the comic ray flux above 10 19.6 eV.…”

Section: Implications For Sources Of Uhecr Below 10 20 Evmentioning

confidence: 99%

Small‐Scale Clustering in the Isotropic Arrival Distribution of Ultra–High‐Energy Cosmic Rays and Implications for Their Source Candidates

Yoshiguchi

Nagataki

Tsubaki

et al. 2003

ApJ

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We present numerical simulations on the propagation of ultra-high-frequency protons with energies of 10 19.5 -10 22 eV in extragalactic magnetic fields over 1 Gpc. We use the Optical Redshift Survey (ORS) galaxy sample, which allows us to accurately quantify the contribution of nearby sources to the energy spectrum and the arrival distribution, as a source model. The sample is corrected, taking the selection effect and absence of galaxies in the zone of avoidance (jbj < 20 ) into account. We calculate three observable quantities-cosmicray spectrum, harmonic amplitude, and two-point correlation function-from our data of numerical simulations. With these quantities, we compare the results of our numerical calculations with the observation. We find that the arrival distribution of ultra-high-energy cosmic rays (UHECRs) becomes most isotropic as sources are restricted to to luminous galaxies ðM lim ¼ À20:5Þ. However, it is not isotropic enough to be consistent with the Akeno Giant Air Shower Array (AGASA) observation, even for M lim ¼ À20:5. In order to obtain a sufficiently isotropic arrival distribution, we randomly select sources more luminous than À20.5 mag from the ORS sample, which contribute to the observed cosmic-ray flux, and investigate the dependence of the results on their number. We show that three observable quantities, including the GreisenZatsepin-Kuz'min (GZK) cutoff of the energy spectrum, can be reproduced in the case that the number fraction $10 À1.7 of the ORS galaxies more luminous than À20.5 mag is selected as UHECR sources. In terms of the source number density, this constraint corresponds to $10 À6 Mpc À3 . However, since the mean number of sources within the GZK sphere is only $0.5 in this case, the eight AGASA events above 10 20.0 eV, which do not together constitute clustered events, cannot be reproduced. On the other hand, if the cosmic-ray flux measured by the High Resolution Fly's Eye EHE Cosmic-Ray Detector (HiRes), which is consistent with the GZK cutoff, is correct and observational features about the arrival distribution of UHECRs are same as the AGASA, our source model can explain both the arrival distribution and the flux at the same time. Thus, we conclude that a large fraction of the eight AGASA events above 10 20 eV might originate in the top-down scenarios or that the cosmic-ray flux measured by the HiRes experiment might be better. We also discuss the origin of UHECRs below 10 20.0 eV through comparisons between the number density of astrophysical source candidates and our result ($10 À6 Mpc À3 ).

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Section: Implications For Sources Of Uhecr Below 10 20 Evmentioning

confidence: 99%

Small‐Scale Clustering in the Isotropic Arrival Distribution of Ultra–High‐Energy Cosmic Rays and Implications for Their Source Candidates

Yoshiguchi

Nagataki

Tsubaki

et al. 2003

ApJ

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“…Such a possibility is considered e.g. in models describing particle acceleration in black hole magnetospheres (Beskin et al 1992;Levinson 2000;Neronov et al 2005;Aharonian & Neronov 2005;Neronov & Aharonian 2007;) in which an almost monochromatic distribution of particles is maintained at the vacuum gap in the magnetosphere. The spectrum of synchrotron and/or curvature emission from electrons and/or protons accelerated in the vacuum gap can be very hard.…”

Section: Vacuum Gap Acceleration Originmentioning

confidence: 99%

Very hard gamma-ray emission from a flare of Mrk 501

Neronov

Semikoz

Taylor

2012

A&A

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Aims. We investigate the peculiar properties of a large TeV γ-ray flare from Mrk 501 detected during the 2009 multiwavelength campaign. Methods. We identified the counterpart of the flare in the Fermi/LAT telescope data and studied its spectral and timing characteristics. Results. A strong order-of-magnitude increase of the very-high-energy γ-ray flux during the flare was not accompanied by an increase in the X-ray flux, so that the flare was one of the "orphan"-type TeV flares observed in BL Lacs. The flare lasted about one month at energies above 10 GeV. The flaring source spectrum in the 10-200 GeV range was very hard, with a photon index Γ = 1.1 ± 0.2, harder than that observed in any other blazar in the γ-ray band. No simultaneous flaring activity was detected below 10 GeV. Different variability properties of the emission below and above 10 GeV indicate the existence of two separate components in the spectrum. We investigate possible explanations of the very hard flaring component. We consider, among others, the possibility that the flare is produced by an electromagnetic cascade initiated by very-high-energy γ-rays in the intergalactic medium. Within such an interpretation, peculiar spectral and temporal characteristics of the flare could be explained if the magnetic field in the intergalactic medium is on the order of 10 −17 −10 −16 G.

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“…In general, there are several acceleration mechanisms that might provide very high Lorentz factors. We show that processes such as Fermi-type acceleration (Catanese & Weekes 1999) and acceleration owing the the black hole dynamo mechanism (Levinson 2000) can provide Lorentz factors of the order of ∼10 7−9 close to the supermassive black holes, i.e. at r ∼ R g , where R g ≡ 2GM BH /c 2 ≈ 3M 9 × 10 14 cm is the gravitational radius of the black hole, M 9 ≡ M/(10 9 M ) and M is the solar mass.…”

Section: Resultsmentioning

confidence: 99%

The generation of connected high and very high energyγ-rays and radio emission in active galactic nuclei

Osmanov

2011

A&A

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Aims. We consider relativistic electrons in magnetospheric flows close to a supermassive black hole and study the mechanism of quasi-linear diffusion (QLD) to investigate the correlation between γ-ray and radio emission in active galactic nuclei. Methods. Moving in the nonuniform magnetic field, the particles experience a force that is responsible for the conservation of the adiabatic invariant. This force, together with the radiation reaction force, tends to decrease the pitch angles. Contrary to this, the QLD attempts to increase the pitch angle, and this maintains the synchrotron emission regime. To examine the balance between the QLD and the aforementioned dissipative factors we investigate the quasi-stationary state by applying the kinetic equation. Results. Considering the magnetospheric plasma close to the supermassive black hole, we examined the efficiency of the QLD for different parameters. By examining the cyclotron instability, we show that despite the efficient dissipative factors, the cyclotron modes excite transverse and longitudinal-transversal waves, which lead to the QLD. We find that the QLD provides a connection of emission in the γ-ray and radio domains. We show that under favourable conditions the radio emission from 22 MHz to 9 GHz on the mpc scale is associated with γ-ray emission from 900 GeV down to 9 GeV on the same scale.

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Particle Acceleration and Curvature TeV Emission by Rotating, Supermassive Black Holes

Cited by 120 publications

References 25 publications

Small‐Scale Clustering in the Isotropic Arrival Distribution of Ultra–High‐Energy Cosmic Rays and Implications for Their Source Candidates

Small‐Scale Clustering in the Isotropic Arrival Distribution of Ultra–High‐Energy Cosmic Rays and Implications for Their Source Candidates

Very hard gamma-ray emission from a flare of Mrk 501

The generation of connected high and very high energyγ-rays and radio emission in active galactic nuclei

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