Direct measurements reveal charge-dependent spectral softenings in primary cosmic rays at a common rigidity of ~15 TV, rejecting mass-dependent softening at >99.999% confidence.
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Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth
10 Pith papers cite this work. Polarity classification is still indexing.
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abstract
The unexpectedly high flux of cosmic ray positrons detected at Earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. We report the detection, using the HighAltitude Water Cherenkov Observatory (HAWC), of extended tera-electron volt gamma-ray emission coincident with the locations of two nearby middle-aged pulsars (Geminga and PSR B0656+14). The HAWC observations demonstrate that these pulsars are indeed local sources of accelerated leptons, but the measured tera-electron volt emission profile constrains the diffusion of particles away from these sources to be much slower than previously assumed. We demonstrate that the leptons emitted by these objects are therefore unlikely to be the origin of the excess positrons, which may have a more exotic origin.
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PHECT is a configurable computation tool for pulsar halo gamma-ray emission using multiple transport models and stable finite-volume discretizations.
The curved spectrum of the young pulsar halo LHAASO J0248+6021 is explained by a time-dependent energy-loss bump in the electron spectrum that remains close to the cutoff, unifying it with the shifted bump observed in the older Geminga halo.
Discrete ICS simulation shows continuous approximations overestimate evolved cutoff energies, leading to lower inferred electron injection cutoffs for Geminga at 95% CL and potential overestimation of acceleration in PeV sources.
A two-zone diffusion model fitted to HAWC morphology and spectrum data constrains Geminga's slow-diffusion zone to 30-70 pc and injection index p ≤ 2.17, reproducing AMS-02 positrons as a derived outcome.
The bow shock pulsar wind nebula around PSR J0437-4715 explains the GeV-TeV positron excess and hundreds-of-GeV antiproton flux with an energy-independent ratio by using 25% of the pulsar's wind power.
HAWC observations yield no TeV detections from spider MSPs, with upper limits indicating they are unlikely to contribute substantially to Galactic diffuse emission at TeV energies.
Diffuse gamma-ray emission detected toward Berkeley 87 with 0.36° extension and photon index 2.68, favoring a hadronic origin due to dense gas and stellar winds.
Simulations indicate that CTA's angular resolution and LHAASO-KM2A's large area will improve morphological separation of diffusion-based pulsar halos from simpler spatial models.
SWGO is proposed as a wide-field VHE gamma-ray survey instrument with a compact inner detector array and sparser outer array, estimated at 54M USD construction cost and full operations by 2026.
citing papers explorer
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Charge-dependent spectral softenings of primary cosmic-rays below the knee
Direct measurements reveal charge-dependent spectral softenings in primary cosmic rays at a common rigidity of ~15 TV, rejecting mass-dependent softening at >99.999% confidence.
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PHECT: A lightweight computation tool for pulsar halo emission
PHECT is a configurable computation tool for pulsar halo gamma-ray emission using multiple transport models and stable finite-volume discretizations.
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Spectral energy-loss bump and $\gamma$-ray pulsar halos
The curved spectrum of the young pulsar halo LHAASO J0248+6021 is explained by a time-dependent energy-loss bump in the electron spectrum that remains close to the cutoff, unifying it with the shifted bump observed in the older Geminga halo.
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Discrete treatment of inverse Compton scattering: implications on parameter estimation in gamma-ray astronomy
Discrete ICS simulation shows continuous approximations overestimate evolved cutoff energies, leading to lower inferred electron injection cutoffs for Geminga at 95% CL and potential overestimation of acceleration in PeV sources.
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Constraining the slow-diffusion zone size and electron injection spectral index for the Geminga pulsar halo
A two-zone diffusion model fitted to HAWC morphology and spectrum data constrains Geminga's slow-diffusion zone to 30-70 pc and injection index p ≤ 2.17, reproducing AMS-02 positrons as a derived outcome.
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On the contribution of the bow shock pulsar wind nebula PSR J0437-4715 to the observed fluxes of GeV-TeV positrons and antiprotons
The bow shock pulsar wind nebula around PSR J0437-4715 explains the GeV-TeV positron excess and hundreds-of-GeV antiproton flux with an energy-independent ratio by using 25% of the pulsar's wind power.
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Search for TeV emission from spider millisecond pulsars with HAWC
HAWC observations yield no TeV detections from spider MSPs, with upper limits indicating they are unlikely to contribute substantially to Galactic diffuse emission at TeV energies.
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Diffuse gamma-ray emission in the vicinity of open cluster Berkeley 87
Diffuse gamma-ray emission detected toward Berkeley 87 with 0.36° extension and photon index 2.68, favoring a hadronic origin due to dense gas and stellar winds.
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Resolving diffusion signatures in distant pulsar halos with current and future experiments
Simulations indicate that CTA's angular resolution and LHAASO-KM2A's large area will improve morphological separation of diffusion-based pulsar halos from simpler spatial models.
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The Southern Wide-Field Gamma-Ray Observatory (SWGO): A Next-Generation Ground-Based Survey Instrument for VHE Gamma-Ray Astronomy
SWGO is proposed as a wide-field VHE gamma-ray survey instrument with a compact inner detector array and sparser outer array, estimated at 54M USD construction cost and full operations by 2026.