Limitations on the photo-disintegration process as a source of VHE photons

Aharonian, F.; Taylor, A. M.

doi:10.1016/j.astropartphys.2010.08.004

Cited by 16 publications

(8 citation statements)

References 19 publications

(29 reference statements)

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“…On the other hand, nuclei interact with lowenergy photons in the source via the photodisintegration process, leading to subsequent (almost prompt) ∼ 0.2 TeV γ A,5 gamma rays from daughter excited nuclei. This signal is useful as a unique probe of nuclei acceleration as well as syn-chrotron and inverse-Compton gamma rays from pairs generated via the Bethe-Heitler process (Murase & Beacom 2010a;Aharonian & Taylor 2010). There are a multitude of potential signatures to be explored.…”

Section: Discussionmentioning

confidence: 99%

The Survival of Nuclei in Jets Associated With Core-Collapse Supernovae and Gamma-Ray Bursts

Horiuchi

Murase

Ioka

et al. 2012

ApJ

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Heavy nuclei such as nickel-56 are synthesized in a wide range of core-collapse supernovae (CCSN), including energetic supernovae associated with gamma-ray bursts (GRBs). Recent studies suggest that jet-like outflows are a common feature of CCSN. These outflows may entrain synthesized nuclei at launch or during propagation, and provide interesting multi-messenger signals including heavy ultra-high-energy cosmic rays. Here, we investigate the destruction processes of nuclei during crossing from the stellar material into the jet material via a cocoon, and during propagation after being successfully loaded into the jet. We find that nuclei can survive for a range of jet parameters because collisional cooling is faster than spallation. While canonical high-luminosity GRB jets may contain nuclei, magnetic-dominated models or low-luminosity jets with small bulk Lorentz factors are more favorable for having a significant heavy nuclei component.

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Section: Discussionmentioning

confidence: 99%

The Survival of Nuclei in Jets Associated With Core-Collapse Supernovae and Gamma-Ray Bursts

Horiuchi

Murase

Ioka

et al. 2012

ApJ

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“…The Doppler-boosted gamma-ray emission due to the deexcitation of these nuclei with Lorentz factor Γ ≥ 10 5 may lead, in principle, to a rather narrow lines at energy E = Γ E * ∼ 100 GeV (typically the prompt de-excitation gamma-ray lines are produced with energy in the frame of the nucleus E * ∼ 1 MeV). However, the efficiency of this mechanism in typical astrophysical environments is very low (Aharonian & Taylor 2010). Also, the disintegration of the primary nuclei would lead to emission of a large number of lines from secondary nuclei, and eventually to a rather broad distribution.…”

Section: Astrophysical Vhe Gamma-ray Lines?mentioning

confidence: 99%

Cold ultrarelativistic pulsar winds as potential sources of galactic gamma-ray lines above 100 GeV

Aharonian

Khangulyan

Malyshev

2012

A&A

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Context. The evidence of line-like spectral features above 100 GeV, in particular at 130 GeV, which have been recently reported from some parts of the Galactic plane, poses serious challenges for any interpretation of this surprise discovery. It is generally believed that the unusually narrow profile of the spectral line cannot be explained by conventional processes in astrophysical objects, and, if real, is likely to be associated with dark matter. Aims. In this paper we argue that cold ultrarelativistic pulsar winds can be alternative sources of very narrow gamma-ray lines. Methods. We demonstrate that Comptonization of a cold ultrarelativistic electron-positron pulsar wind in the deep Klein-Nishina regime can readily provide very narrow (ΔE/E ≤ 0.2) distinct gamma-ray line features. To verify this prediction, we produced photon-count maps based on the Fermi LAT data in the energy interval 100 to 140 GeV. Results. We confirm earlier reports of the presence of marginal gamma-ray line-like signals from three regions of the Galactic plane. Although the maps show some structure inside these regions, unfortunately the limited photon statistics do not allow any firm conclusion in this regard. Conclusions. The confirmation of 130 GeV line emission by low-energy threshold atmospheric Cherenkov telescope systems, in particular by the new 28 m diameter dish of the H.E.S.S. array, would be crucial for resolving the spatial structure of the reported hotspots, and thus for distinguishing between the dark matter and pulsar origins of the "Fermi Lines".

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“…Nevertheless, as internal γγ attenuation is then mitigated [137], GeV-TeV signals from nuclear deexcitation, photopair creation or nuclear synchrotron emission may be observable and provide a unique signature of UHECR nuclei acceleration [172,173]. For example, Lorentz-boosted de-excitation gamma rays at energies ∼ TeV(E A /3 × 10 16 eV), where E A is the energy of CR nuclei, may be detectable from nearby, low-luminosity GRBs (see however [174]). …”

Section: Ultra-high-energy Cosmic Rays and Neutrinosmentioning

confidence: 99%

Gamma-ray burst science in the era of the Cherenkov Telescope Array

Inoue

Granot

O’Brien

et al. 2013

Astroparticle Physics

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We outline the science prospects for gamma-ray bursts (GRBs) with the Cherenkov Telescope Array (CTA), the next-generation ground-based gamma-ray observatory operating at energies above few tens of GeV. With its low energy threshold, large effective area and rapid slewing capabilities, CTA will be able to measure the spectra and variability of GRBs at multi-GeV energies with unprecedented photon statistics, and thereby break new ground in elucidating the physics of GRBs, which is still poorly understood. Such measurements will also provide crucial diagnostics of ultra-high-energy cosmic ray and neutrino production in GRBs, advance observational cosmology by probing the high-redshift extragalactic background light and intergalactic magnetic fields, and contribute to fundamental physics by testing Lorentz invariance violation with high precision. Aiming to quantify these goals, we present some simulated observations of GRB spectra and light curves, together with estimates of their detection rates with CTA. Although the expected detection rate is modest, of order a few GRBs per year, hundreds or more high-energy photons per burst may be attainable once they are detected. We also address various issues related to following up alerts from satellites and other facilities with CTA, as well as follow-up observations at other wavelengths. The possibility of discovering and observing GRBs from their onset including short GRBs during a wide-field survey mode is also briefly discussed.

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Limitations on the photo-disintegration process as a source of VHE photons

Cited by 16 publications

References 19 publications

The Survival of Nuclei in Jets Associated With Core-Collapse Supernovae and Gamma-Ray Bursts

The Survival of Nuclei in Jets Associated With Core-Collapse Supernovae and Gamma-Ray Bursts

Cold ultrarelativistic pulsar winds as potential sources of galactic gamma-ray lines above 100 GeV

Gamma-ray burst science in the era of the Cherenkov Telescope Array

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