TeV gamma rays from BL Lac Objects due to synchrotron radiation of extremely high energy protons

By F. Aharonian. 2000

360 citations recorded by the source corpus.

Abstract One of remarkable features of the gamma-ray blazar Markarian 501 is the reported shape of the TeV spectrum, which during strong flares of the source remains essentially stable despite dramatic variations of the absolute γ-ray flux. I argue that this unusual behavior of the source could be explained assuming that the TeV emission is a result of synchrotron radiation of extremely high energy (E≥1019 eV) protons in highly magnetized (B∼30–100 G) compact regions of the jet with typical size R∼1015–1016 cm and Doppler factor δj≃10–30. It is shown that if protons are accelerated at the maximum possible rate, i.e. tacc=η(rg/c) with so-called gyro-factor η∼1, the synchrotron cooling of protons could not only dominate over other radiative and non-radiative losses, but could also provide good fits (within uncertainties introduced by extragalactic γ-ray extinction) to the γ-radiation of two firmly established TeV blazars — Markarian 501 and Markarian 421. Remarkably, if the proton acceleration takes place in the regime dominated by synchrotron losses, the spectral shape of the Doppler-boosted γ-radiation in the observer's frame is determined essentially by the self-regulated “synchrotron cutoff” at ϵ 0 ≃0.3 δ j η −1 TeV. The hypothesis of the proton-synchrotron origin of TeV flares of BL Lac objects inevitably implies that the energy contained in the form of magnetic field in the γ-ray emitting region exceeds the kinetic energy of accelerated protons.

View Paper: https://www.semanticscholar.org/paper/42fc09fd289a47ab069856b221a8b387b6efbfb8

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

Citations in the corpus

Neutral Beams from Blazar Jets (2002, background): “Detectable synchrotron emission at TeV energies could be radiated by ultrarelativistic protons and ions, but this requires extremely strong magnetic fields, 20–100 G in BL Lac objects (Aharonian 2000; Mücke & Protheroe 2001).”
The Crab Nebula and Pulsar between 500 GeV and 80 TeV: Observations with the HEGRA Stereoscopic Air Cerenkov Telescopes (2004, background): “In a different scenario, pulsed emission is expected to arise as a consequence of inverse Compton scattering of pulsed soft photons by the unshocked wind (Bogovalov & Aharonian 2000).”
The Blazar TXS 0506+056 Associated with a High-energy Neutrino: Insights into Extragalactic Jets and Cosmic-Ray Acceleration (2018, unknown): “We account for all relevant hadronic radiative processes, including photo-meson-induced cascade emission (Mannheim 1993), Bethe-Heitler (BH) pair cascade emission (Petropoulou & Mastichiadis 2015), and synchrotron radiation from protons (Aharonian 2000) and muons.”
The power of blazar jets (2007, background): “The so-called ‘hadronic’ models invoke the presence of highly relativistic protons, directly emitting via synchrotron or inducing electron–positron (e±) pair cascades following protonproton or proton–photon interactions (e.g., Mannheim 1993, Aharonian 2000, Mücke et al. 2003, Atoyan & Dermer 2003).”
CONSTRAINING EMISSION MODELS OF LUMINOUS BLAZAR SOURCES (2009, unknown): “…frequencies νp,syn(γp = γe) = (me/mp) νe,syn, and the relation between the corresponding cooling rates |γ̇p|syn(γp = γe) = (me/mp)3 |γ̇e|syn (see, e.g., Aharonian 2000), one can find the appropriate radiative efficiency around the γ -ray luminosity peak: τp,syn(γp,peak) ≡ t ′−1p,syn t…”
The multifrequency emission of Mrk 501 From radio to TeV gamma-rays (2001, background): “Another possibility is to directly consider the synchrotron emission of extremely high energy protons (Aharonian 2000).”
The blazar sequence: a new perspective (2008, background): “Probably the most basic assumptions of ours is that the emission comes from the acceleration and the radiative cooling of leptons, and we have neglected the possible presence of relativistic hadrons (Mannheim 1993; Aharonian 2000; Mücke et al. 2003).”
Leptohadronic single-zone models for the electromagnetic and neutrino emission of TXS 0506+056 (2018, background): “…scenario that may explain correlated electromagnetic and neutrino emission in blazars is the one-zone, lepto-hadronic model (see e.g. Mannheim 1993; Aharonian 2000; Mücke & Protheroe 2001), where a magnetized compact region inside the relativistic jet carries a population of relativistic…”
A Multimessenger Picture of the Flaring Blazar TXS 0506+056: Implications for High-energy Neutrino Emission and Cosmic-Ray Acceleration (2018, background): “…the γ-ray emission is explained by processes related to relativistic protons: proton-induced EM cascades (Mannheim 1993; Mücke et al. 2003), proton synchrotron emission (Aharonian 2000; Mücke et al. 2003), or intergalactic magnetic cascades induced by UHECRs (Essey et al. 2011; Murase et al. 2012).”
MINUTE-TIMESCALE >100 MeV γ-RAY VARIABILITY DURING THE GIANT OUTBURST OF QUASAR 3C 279 OBSERVED BY FERMI-LAT IN 2015 JUNE (2016, background): “…very small distance scales, the radiative efficiency of the proton-initiated cascade mech- anism (Mannheim & Biermann 1992) is enhanced due to very dense target radiation fields, and that of the protonsynchrotron mechanism (Aharonian 2000) is enhanced due to very strong magnetic fields (B′ & kG).”
LEPTONIC AND HADRONIC MODELING OF FERMI-DETECTED BLAZARS (2013, background): “…synchrotron, and Compton emission from secondary decay products of charged pions, and the output from pair cascades initiated by these high-energy emissions intrinsically absorbed by γ γ pair production (Mannheim & Biermann 1992; Aharonian 2000; Mücke & Protheroe 2001; Mücke et al. 2003).”
Multiwavelength Observations of Strong Flares from the TeV Blazar 1ES 1959+650 (2003, background): “Proton M odels:In proton m odelsthelow-energy radiation isproduced by apopulation ofnon-therm alelectronsand high-energy radiation by accelerated protons,either directly assynchrotron radiation (Aharonian 2000;M uckeetal.2002),orviaaProton Induced Cascade(PIC)(M annheim 1998).”
Active galactic nuclei: what’s in a name? (2017, background): “In hadronic scenarios (e.g. Böttcher et al. 2013) γ -rays are instead assumed to originate from high-energy protons either loosing energy through synchrotron emission (Aharonian 2000) or through photo–meson interactions (Mannheim 1993).”
Electron-positron pairs in physics and astrophysics: from heavy nuclei to black holes (2009, background): “A relevant broad-band information about the cosmic background radiation (CBR) is important for the interpretation of the observed high-energy γ spectra [283, 284, 285, 286].”
Relativistic Jets Shine through Shocks or Magnetic Reconnection (2015, background): “…jet emission has to account for the fact that both blazars and GRBs are characterized by (i) alarge 3 In hadronic models for the gamma-ray emission from blazars,the required maximum Lorentz factor of protons may be even more extreme (Aharonian 2000; Böttcher et al. 2013; Petropoulou et al. 2015).”
BLAZARS AS ULTRA-HIGH-ENERGY COSMIC-RAY SOURCES: IMPLICATIONS FOR TeV GAMMA-RAY OBSERVATIONS (2011, methodology): “One could abandon the standard synchrotron/SSC model and consider a highly magnetized,∼ 10− 100 G jet model, which is needed in hadronic blazar models to accelerate protons to & 1020 eV (Aharonian 2000).”
A Multiwavelength View of the TeV Blazar Markarian 421: Correlated Variability, Flaring, and Spectral Evolution (2005, background): “Alternatively, the jet might be energetically dominated by the magnetic field, and it is the synchrotron radiation from highly relativistic protons that might be responsible for the observed TeV gamma rays (Aharonian 2000; Mücke et al. 2003).”
The physics of gamma-ray bursts & relativistic jets (2014, background): “…they too could contribute to the observed γ-ray radiation from GRBs as described in a number of papers (e.g. Böttcher and Dermer, 1998; Totani, 1998; Aharonian, 2000; Mücke et al., 2003; Reimer et al., 2004; Gupta and Zhang, 2007b; Asano et al., 2009; Fan and Piran, 2008; Razzaque et al., 2010;…”