Constraining positron emission from pulsar populations with AMS-02 data

Orusa, Luca; Manconi, Silvia; Donato, Fiorenza; Di Mauro, Mattia

doi:10.48550/arxiv.2107.06300

Cited by 4 publications

(8 citation statements)

References 60 publications

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“…There is only a small number of pulsar simulations with η < 0.01. Recently, an independent analysis of [72] suggested a similar fraction of spin-down power to cosmic-ray electrons and positrons. We present the simulations that are within the 2σ criterion, but note that even if we used the larger number of simulations that are within 3σ, the results would not differ.…”

Section: Observations At Tev Energies From Dampe and Caletmentioning

confidence: 99%

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Utilizing cosmic-ray positron and electron observations to probe the averaged properties of Milky Way pulsars

Cholis,

Krommydas

2021

Preprint

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Pulsars have long been studied in the electromagnetic spectrum. Their environments are rich in high-energy cosmic-ray electrons and positrons likely enriching the interstellar medium with such particles. In this work we use recent cosmic-ray observations from the AMS-02, CALET and DAMPE collaborations to study the averaged properties of the local Milky Way pulsar population.We perform simulations of the local Milky Way pulsar population, for interstellar medium assumptions in agreement with a range of cosmic-ray nuclei measurements. Each such simulation contains ∼ 10 4 pulsars of unique age, location, initial spin-down power and cosmic-ray electron/positron spectra. We produce more than 7 × 10 3 such Milky Way pulsar simulations. We account for and study i) the pulsars' birth rates and the stochastic nature of their birth, ii) their initial spin-down power distribution, iii) their time evolution in terms of their braking index and characteristic spindown timescale, iv) the fraction of spin-down power going to cosmic-ray electrons and positrons and v) their propagation through the interstellar medium and the Heliosphere. We find that pulsars of ages ∼ 10 5 − 10 7 yr, have a braking index that on average has to be 3 or larger. Given that electromagnetic spectrum observations of young pulsars find braking indices lower than 3, our work provides strong hints that pulsars' braking index increases on average as they age, allowing them to retain some of their rotational energy. Moreover, we find that pulsars have relatively uniform properties as sources of cosmic-ray electrons and positrons in terms of the spectra they produce and likely release O(10%) of their rotational energy to cosmic-rays in the ISM. Finally, we find at 12 GeV positrons a spectral feature that suggests a new subpopulation of positron sources contributing at these energies.

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Section: Observations At Tev Energies From Dampe and Caletmentioning

confidence: 99%

“…This suggests an additional source of high-energy cosmic-ray positrons. Such positrons can come from near-by Milky Way pulsars [40,[57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72]. One alternative to pulsars includes local and recent supernova remnants (SNRs) [73][74][75][76][77][78][79][80][81][82][83].…”

Section: Introductionmentioning

confidence: 99%

Utilizing cosmic-ray positron and electron observations to probe the averaged properties of Milky Way pulsars

Cholis,

Krommydas

2021

Preprint

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“…One of the most promising candidates for the positron sources are pulsars (e.g. Zhang & Cheng 2001;Grimani 2007;Hooper et al 2009;Malyshev et al 2009;Delahaye et al 2010;Cholis et al 2018;Di Mauro et al 2021;Orusa et al 2021). On the other hand, the sudden drop seen at ∼ 1 TeV in the CALET spectrum may be attributed to a single source with a hard injection spectrum.…”

Section: Contribution Of Electron-positron Pair Sourcesmentioning

confidence: 99%

“…The positron component above 100 GeV is apparently a different component from the electron component, which dominates the electron and positron flux. Potential sources of positrons above 100 GeV are pulsars (Cholis et al 2018;Di Mauro et al 2021;Orusa et al 2021) or a single SNR interacting dense medium (Fujita et al 2009;Kohri et al 2016). The spectral bump in the CALET spectrum may be attributed to the positron component.…”

Section: Introductionmentioning

confidence: 99%

“…The dominant component of electron and positron CRs are electrons from SNRs. To investigate the effect of the number fluctuation of nearby sources, we adopt a Monte Carlo method in our calculations (see also Mertsch 2018;Evoli et al 2021;Orusa et al 2021). We examine whether SNRs, which randomly occur, can reproduce the characteristic structures in the CALET spectrum, or if different origins are required.…”

Section: Introductionmentioning

confidence: 99%

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Monte Carlo Study of Electron and Positron Cosmic-Ray Propagation with the CALET Spectrum

Asano,

Asaoka,

Akaike

et al. 2021

Preprint

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Focusing on the electron and positron spectrum measured with CALET, which shows characteristic structures, we calculate flux contributions of cosmic rays escaped from supernova remnants, which were randomly born. We adopt a Monte Carlo method to take into account the stochastic property of births of nearby sources. We find that without a complicated energy dependence of the diffusion coefficient, simple power-law diffusion coefficients can produce spectra similar to the CALET spectrum even with a dispersion in the injection index. The positron component measured with AMS-02 is consistent with a bump-like structure around 300 GeV in the CALET spectrum. One to three nearby supernovae can contribute up to a few tens of percent of the CALET flux at 2-4 TeV, ten or more unknown and distant ( 500 pc) supernovae account for the remaining several tens of percent of the flux. The CALET spectrum, showing a sharp drop at ∼ 1 TeV, allows for a contribution of cosmic rays from an extraordinary event which occured ∼ 400 kyr ago. This type of event releases electrons/positrons with a total energy more than 10 times the average energy for usual supernovae, and its occurrence rate is lower than 1/300 of the usual supernova rate.

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Utilizing cosmic-ray positron and electron observations to probe the averaged properties of Milky Way pulsars

Cholis

Krommydas

2022

Phys. Rev. D

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Pulsars have long been studied in the electromagnetic spectrum. Their environments are rich in high-energy cosmic-ray electrons and positrons likely enriching the interstellar medium with such particles. In this work we use recent cosmic-ray observations from the AMS-02, CALET and DAMPE collaborations to study the averaged properties of the local Milky Way pulsar population.We perform simulations of the local Milky Way pulsar population, for interstellar medium assumptions in agreement with a range of cosmic-ray nuclei measurements. Each such simulation contains ∼ 10 4 pulsars of unique age, location, initial spin-down power and cosmic-ray electron/positron spectra. We produce more than 7 × 10 3 such Milky Way pulsar simulations. We account for and study i) the pulsars' birth rates and the stochastic nature of their birth, ii) their initial spin-down power distribution, iii) their time evolution in terms of their braking index and characteristic spindown timescale, iv) the fraction of spin-down power going to cosmic-ray electrons and positrons and v) their propagation through the interstellar medium and the Heliosphere. We find that pulsars of ages ∼ 10 5 − 10 7 yr, have a braking index that on average has to be 3 or larger. Given that electromagnetic spectrum observations of young pulsars find braking indices lower than 3, our work provides strong hints that pulsars' braking index increases on average as they age, allowing them to retain some of their rotational energy. Moreover, we find that pulsars have relatively uniform properties as sources of cosmic-ray electrons and positrons in terms of the spectra they produce and likely release O(10%) of their rotational energy to cosmic rays in the ISM. Finally, we find at 12 GeV positrons a spectral feature that suggests a new subpopulation of positron sources contributing at these energies.

show abstract

Constraining positron emission from pulsar populations with AMS-02 data

Cited by 4 publications

References 60 publications

Utilizing cosmic-ray positron and electron observations to probe the averaged properties of Milky Way pulsars

Utilizing cosmic-ray positron and electron observations to probe the averaged properties of Milky Way pulsars

Monte Carlo Study of Electron and Positron Cosmic-Ray Propagation with the CALET Spectrum

Utilizing cosmic-ray positron and electron observations to probe the averaged properties of Milky Way pulsars

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