Expected signatures from hadronic emission processes  in the TeV spectra of BL Lacertae objects

Zech, A.; Cerruti, M.; Mazin, D.

doi:10.1051/0004-6361/201629997

Cited by 48 publications

(56 citation statements)

References 71 publications

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“…Gamma-ray emission via synchrotron radiation of protons or muons is mostly unimportant for the range of magnetic fields and proton energies considered here, except for a limited region of parameter space. The results presented here have been cross-checked with the codes developed in Cerruti et al (2015) and Zech et al (2017).…”

Section: Model Descriptionmentioning

confidence: 99%

The Blazar TXS 0506+056 Associated with a High-energy Neutrino: Insights into Extragalactic Jets and Cosmic-Ray Acceleration

Ansoldi

Antonelli

Arcaro

et al. 2018

ApJL

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202

154

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A neutrino with energy ∼290 TeV, IceCube-170922A, was detected in coincidence with the BL Lac object TXS0506+056 during enhanced gamma-ray activity, with chance coincidence being rejected at ∼3σ level. We monitored the object in the very-high-energy (VHE) band with the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes for ∼41 hr from 1.3 to 40.4 days after the neutrino detection. Day-timescale variability is clearly resolved. We interpret the quasi-simultaneous neutrino and broadband electromagnetic observations with a novel one-zone lepto-hadronic model, based on interactions of electrons and protons coaccelerated in the jet with external photons originating from a slow-moving plasma sheath surrounding the faster jet spine. We can reproduce the multiwavelength spectra of TXS 0506+056 with neutrino rate and energy compatible with IceCube-170922A, and with plausible values for the jet power of 10 4 10 erg s 45 46 1 -´-. The steep spectrum observed by MAGIC is concordant with internal γγ absorption above ∼100 GeV entailed by photohadronic production of a ∼290 TeV neutrino, corroborating a genuine connection between the multi-messenger signals. In contrast to previous predictions of predominantly hadronic emission from neutrino sources, the gamma-rays can be mostly ascribed to inverse Compton upscattering of external photons by accelerated electrons. The X-ray and VHE bands provide crucial constraints on the emission from both accelerated electrons and protons. We infer that the maximum energy of protons in the jet comoving frame can be in the range ∼10 14 -10 18 eV.

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Section: Model Descriptionmentioning

confidence: 99%

The Blazar TXS 0506+056 Associated with a High-energy Neutrino: Insights into Extragalactic Jets and Cosmic-Ray Acceleration

Ansoldi

Antonelli

Arcaro

et al. 2018

ApJL

Self Cite

202

154

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“…Using these parameters, we cannot fit the SED of PKS 1424+240. The reason is that in their numerical simulation the synchrotron emission by muons is not computed, while this component is important in the VHE regime, and increases the hardening of the γ-ray emission (Zech et al 2017). …”

Section: Emission At the Sourcementioning

confidence: 99%

Luminous and high-frequency peaked blazars: the origin of the γ-ray emission from PKS 1424+240

Cerruti

Benbow

Chen

et al. 2017

A&A

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Context. The current generation of ground-based Cherenkov telescopes, together with the LAT instrument on-board the Fermi satellite, have greatly increased our knowledge of γ-ray blazars. Among them, the high-frequency-peaked BL Lacertae object (HBL) PKS 1424+240 (z 0.6) is the farthest persistent emitter of very-high-energy (VHE; E ≥ 100 GeV) γ-ray photons. Current emission models can satisfactorily reproduce typical blazar emission assuming that the dominant emission process is synchrotron-self-Compton (SSC) in HBLs; and external-inverse-Compton (EIC) in low-frequency-peaked BL Lacertae objects and flat-spectrum-radio-quasars. Alternatively, hadronic models are also able to correctly reproduce the γ-ray emission from blazars, although they are in general disfavored for bright quasars and rapid flares. Aims. The blazar PKS 1424+240 is a rare example of a luminous HBL, and we aim to determine which is the emission process most likely responsible for its γ-ray emission. This will impact more generally our comprehension of blazar emission models, and how they are related to the luminosity of the source and the peak frequency of the spectral energy distribution. Methods. We have investigated different blazar emission models applied to the spectral energy distribution of PKS 1424+240. Among leptonic models, we study a one-zone SSC model (including a systematic study of the parameter space), a two-zone SSC model, and an EIC model. We then investigated a blazar hadronic model, and finally a scenario in which the γ-ray emission is associated with cascades in the line-of-sight produced by cosmic rays from the source. Results. After a systematic study of the parameter space of the one-zone SSC model, we conclude that this scenario is not compatible with γ-ray observations of PKS 1424+240. A two-zone SSC scenario can alleviate this issue, as well as an EIC solution. For the latter, the external photon field is assumed to be the infra-red radiation from the dusty torus, otherwise the VHE γ-ray emission would have been significantly absorbed. Alternatively, hadronic models can satisfactorily reproduce the γ-ray emission from PKS 1424+240, both as in-source emission and as cascade emission.

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“…The 30DorC complex exhibits extreme conditions and could represent another type of PeVatron to study with CTA [6]. The multi-TeV range will also explore the most powerful acceleration mechanisms in nearby AGN and in AGN flares, and search for signatures of hadronic versus leptonic processes in such extragalactic sources [7,8]. Studying the propagation along the line of sight of extremely high energy photons from AGN will offer the opportunity to analyze the diffuse extragalactic background light (EBL) and the intergalactic magnetic field, and to probe the fine structure of spacetime, looking for potential clues of LIV [9].…”

Section: Perspectives On Multi-tev Sciencesmentioning

confidence: 99%

Observing the sky at extremely high energies with CTA: Status of the GCT project

Sol¹,

Greenshaw²,

Blanc³

et al. 2017

Proceedings of 35th International Cosmic Ray Conference — PoS(ICRC2017)

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The Cherenkov Telescope Array is the main global project of ground-based gamma-ray astronomy for the coming decades. Performance will be significantly improved relative to present instruments, allowing a new insight into the high-energy Universe [1]. The nominal CTA southern array will include a sub-array of seventy 4 m telescopes spread over a few square kilometers to study the sky at extremely high energies, with the opening of a new window in the multi-TeV energy range. The Gamma-ray Cherenkov Telescope (GCT) is one of the proposed telescope designs for that sub-array. The GCT prototype recorded its first Cherenkov light on sky in 2015. After an assessment phase in 2016, new observations have been performed successfully in 2017. The GCT collaboration plans to install its first telescopes and cameras on the CTA site in Chile in 2018-2019 and to contribute a number of telescopes to the subsequent CTA production phase.

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Expected signatures from hadronic emission processes in the TeV spectra of BL Lacertae objects

Cited by 48 publications

References 71 publications

The Blazar TXS 0506+056 Associated with a High-energy Neutrino: Insights into Extragalactic Jets and Cosmic-Ray Acceleration

The Blazar TXS 0506+056 Associated with a High-energy Neutrino: Insights into Extragalactic Jets and Cosmic-Ray Acceleration

Luminous and high-frequency peaked blazars: the origin of the γ-ray emission from PKS 1424+240

Observing the sky at extremely high energies with CTA: Status of the GCT project

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