Features in cosmic-ray lepton data unveil the properties of nearby cosmic accelerators

Fornieri, Ottavio; Gaggero, Daniele; Grasso, Dario

doi:10.1088/1475-7516/2020/02/009

Cited by 50 publications

(52 citation statements)

References 95 publications

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“…[10,11], CALET [12] and DAMPE [13] collaborations have also measured a break at 1 TeV in the all-electron spectrum, which could be a signature of a local CR electron source. As first shown in [14] and further discussed in [15], this source should not produce electrons and positrons in similar amounts in order to be compatible with the observed positron fraction: a nearby Supernova Remnant (SNR) would hence fulfill this requirements. Among the known nearby SNRs, Vela and Cygnus Loop appeared as promising candidates due to their age and distance, but recent studies have shown that their expected contribution to the all-electron flux at high-energy ( > 1 TeV) would be sub-dominant (see for example [16]).…”

Section: Introductionmentioning

confidence: 88%

A unified picture for three different cosmic-ray observables.

Fornieri¹,

Gaggero²,

Guberman³

et al. 2021

Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021)

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We present here a unified scenario that connects three peculiar spectral features recently reported in the spectra of charged cosmic rays (CRs). The spectral hardening measured by AMS-02 in the hadronic spectra above ∼ 250 GeV is here interpreted as a diffusion imprint, and modeled by means of a transport coefficient that smoothly hardens with rigidity. We implement such propagation framework to solve the transport equation with the DRAGON2 numerical code in order to determine the large-scale contribution to the CR fluxes. On top of this solution we explore the hypothesis of a nearby, hidden Supernova Remnant (SNR) to be responsible for the high-energy (above ∼ 100 GeV) all-lepton flux, in particular for the spectral break consistently measured by all the space-and ground-based detectors around 1 TeV. We compute such contribution analytically adopting the same propagation setup implemented for the large-scale background. Simultaneously, we find the signature of the same source in the peculiar bump structure observed by the DAMPE Collaboration in the proton spectrum, consisting of a strong hardening at ∼ 500 GeV and a softening at 13 TeV. We validate our hypothesis with the CR dipole-anisotropy (DA) amplitude and phase. In particular, we interpret the high-energy data (above 10 TeV) pointing towards the Galactic Center as the convolution of the directional fluxes of the large-scale-background sources, whereas the DA amplitude below that energy is compatible with the predictions of our model and is therefore considered as a signature of the nearby SNR that we invoke.

show abstract

Section: Introductionmentioning

confidence: 88%

A unified picture for three different cosmic-ray observables.

Fornieri¹,

Gaggero²,

Guberman³

et al. 2021

Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021)

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“…For the CR distributions of leptons and nuclei, we adopt the CR densities obtained by solving the CR diffusion-loss equation (including re-acceleration) under the assumption of a homogeneous and isotropic diffusion coefficient by means of the DRAGON code (Evoli et al 2017(Evoli et al , 2018. All the assumptions and parameters of the adopted CR model are discussed in Fornieri et al (2020), where the authors compared their predictions with the most relevant local CR observables (namely: proton, helium, carbon and oxygen flux, boron-to-carbon ratio, low-energy lepton and antiproton fluxes) over a wide energy range (from ≃ 10 MeV up to ≃ 1 TeV).…”

Section: Some Relevant Applicationsmentioning

confidence: 99%

Simulating the Galactic multi-messenger emissions with HERMES

Dundovic

Evoli

Gaggero

et al. 2021

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Context. The study of nonthermal processes such as synchrotron emission, inverse Compton scattering, bremsstrahlung, and pion production is crucial to understanding the properties of the Galactic cosmic-ray population, to shed light on their origin and confinement mechanisms, and to assess the significance of exotic signals possibly associated to new physics. Aims. We present a public code called HERMES which is designed generate sky maps associated to a variety of multi-messenger and multi-wavelength radiative processes, spanning from the radio domain all the way up to high-energy gamma-ray and neutrino production. Methods. We describe the physical processes under consideration, the code concept and structure, and the user interface, with particular focus on the python-based interactive mode. In particular, present the modular and flexible design that allows the user to easily extend the numerical package according to their needs. Results. In order to demonstrate the capabilities of the code, we describe the details of a comprehensive set of sky maps and spectra associated to all physical processes included in the code. We comment in particular on the radio, gamma-ray, and neutrino maps, and mention the possibility of studying signals stemming from dark matter annihilation. Conclusions. HERMES can be successfully applied to constrain the properties of the Galactic cosmic-ray population, improve our understanding of the diffuse Galactic radio, gamma-ray, and neutrino emission, and search for signals associated to particle dark matter annihilation or decay.

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“…Multi-wavelength observations show the presence of five SNRs in the local region (within ∼ 1 kpc) surrounding the Earth 3 , identified with the names Vela Jr, Vela, Cygnus Loop, Simeis-147, IC-443. A bayesian fit of these sources is performed in [4], based on AMS-02 [22] plus H.E.S.S. [3] all-lepton data, showing that, neglecting the rigid contribution of H.E.S.S.…”

Section: Local Electron Accelerators Explain the High-energy Electronmentioning

confidence: 99%

“…Here, we investigate whether nearby old cosmic accelerators such as supernova remnants (SNRs) and relatively young pulsar wind nebulae (PWNe) can explain those experimental results in the framework of a large-scale CR transport setup tuned on the most updated CR nuclei data. For the extended version of the results presented we refer to the principal paper [4].…”

Section: Introductionmentioning

confidence: 99%

Unveiling the Origin of Cosmic-ray Leptons in Light of the Recent HAWC TeV-halo Observations

Fornieri¹,

Gaggero²,

Grasso³

2019

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019)

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The interpretation of cosmic-ray (CR) data still represents a significant challenge: a coherent interpretation of the measured CR spectra is hampered by our incomplete knowledge about both the acceleration mechanisms and the transport properties across the Galaxy. The main challenge in this context is to identify a unified picture that includes all the available observables. To this aim, we first perform a multi-channel fit of the available CR data based on the DRAGON numerical code, to set the relevant propagation parameters. Then, we discuss several physically-motivated possibilities (i.e. recent burst, constant-luminosity, time-dependent emission) for the injection of e + e − pairs accelerated at nearby antimatter factories, such as pulsar wind nebulae, and compute their propagation. Finally, we address the all-lepton spectrum and assess the contributions of both young, nearby supernova remnants, and possibly an additional hidden source, to the observed CR lepton flux above ∼ 1 TeV recently measured by H.E.S.S., VERITAS, CALET and DAMPE.

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Features in cosmic-ray lepton data unveil the properties of nearby cosmic accelerators

Cited by 50 publications

References 95 publications

A unified picture for three different cosmic-ray observables.

A unified picture for three different cosmic-ray observables.

Simulating the Galactic multi-messenger emissions with HERMES

Unveiling the Origin of Cosmic-ray Leptons in Light of the Recent HAWC TeV-halo Observations

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