Very-High-Energy Emission From Pulsars

Abstract

Air-Cherenkov telescopes have detected pulsations at energies above 50 GeV from a growing number of Fermi pulsars. These include the Crab, Vela, PSR B1706-44 and Geminga, with the first two having pulsed detections above 1 TeV. In some cases, there appears to be very-high-energy (VHE) emission that is an extension of the Fermi spectra to high energies, while in other cases, additional higher-energy spectral components that require a separate emission mechanism may be present. We present results of broad-band spectral modeling using global magnetosphere fields and multiple emission mechanisms that include synchro-curvature (SC) and inverse Compton scattered (ICS) radiation from accelerated particles (primaries) and synchrotron-self Compton (SSC) emission from lower-energy pairs. Our models predict three distinct VHE components: SC from primaries whose high-energy tail can extend to 100 GeV, SSC from pairs that can extend to several TeV and ICS from primary particles accelerated in the current sheet, scattering pair synchrotron radiation, that appears beyond 10 TeV. Our models suggest that H.E.S.S.-II and MAGIC have detected the high-energy tail of the primary SC component that produces the Fermi spectrum in Vela, Geminga and PSR B1706-44. We argue that the ICS component peaking above 10 TeV from Vela has been seen by H.E.S.S. Detection of this emission component from the Crab and other pulsars is possible with HAWC and CTA, and directly measures the maximum particle energy in pulsars.

28 pages, 14 figures, accepted for publication in Astrophysical Journal

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Cited by in corpus (13)

• The Third Fermi Large Area Telescope Catalog of Gamma-ray Pulsars
• Discovery of a Radiation Component from the Vela Pulsar Reaching 20 Teraelectronvolts
• The Emission Physics of Millisecond Pulsars
• The Fundamental Plane Relation for Gamma-Ray Pulsars Implied by 4FGL
• A NICER View on the 2020 Magnetar-Like Outburst of PSR J1846-0258
• Observational connection of non-thermal X-ray emission from pulsars with their timing properties and thermal emission
• Crab Pulsar: IXPE Observations Reveal Unified Polarization Properties Across Optical and Soft X-Ray Bands
• Absence of TeV halos around millisecond pulsars
• Prediction of radio-quiet gamma-ray pulsar distances using the Fundamental Plane relation
• Detection of the Geminga pulsar at energies down to 20 GeV with the LST-1 of CTAO
• Towards Modelling AR Sco: Generalised Particle Dynamics and Strong Radiation-Reaction Regimes
• A mechanism-independent methodology for modeling γ-ray phaseograms of pulsars in the framework of north-south symmetry
• Towards Modelling AR Sco: Calibration -- Reproducing High-Energy Pulsar Emission and Testing Convergence to Aristotelian Electrodynamics