A systematic synchro-curvature modelling of pulsar $\gamma$-ray spectra unveils hidden trends

Abstract

$\gamma$-ray radiation from pulsars is usually thought to be mostly produced by the synchro-curvature losses of accelerated particles. Here we present a systematic study of all currently reported, good-quality Fermi-LAT pulsar spectral data. We do so by applying a model which follows the particle dynamics and consistently computes the emission of synchro-curvature radiation. By fitting observational data on a case by case basis, we are able to obtain constraints about the parallel electric field, the typical lengthscale over which particles emit the bulk of the detected radiation, and the number of involved particles. The model copes well with data of several dozens of millisecond and young pulsars. By correlating the inferred model parameters with the observed timing properties, some trends are discovered. First, a non-negligible part of the radiation comes from the loss of perpendicular momentum soon after pair creation. Second, the electric field strongly correlates with both the inverse of the emission lengthscale and the magnetic field at light cylinder, thus ruling out models with high-energy photon production close to the surface. These correlations unify young and millisecond pulsars under the same physical scenario, and predict that magnetars are intrinsically $\gamma$-ray quiet via syncrhro-curvature processes, since magnetospheric particles are not accelerated enough to emit a detectable $\gamma$-ray flux.

arXiv commentAccepted for publication in MNRAS main journal. 25 pages, 4 tables, 16 figures

References in corpus (15)

• The Second Fermi Large Area Telescope Catalog of Gamma-ray Pulsars
• Modeling the spectral evolution of PWNe inside SNRs
• Pulsar Polar Cap Heating and Surface Thermal X-Ray Emission II. Inverse Compton Radiation Pair Fronts
• Observation of Pulsed Gamma-rays Above 25 GeV from the Crab Pulsar with MAGIC
• Constraining Pulsar Magnetosphere Geometry with Gamma-Ray Light Curves
• The Vela Pulsar: Results from the First Year of Fermi LAT Observations
• PSR J2021+4026 in the Gamma Cygni region: the first variable gamma-ray pulsar seen by the Fermi LAT
• The very-high energy emission from pulsars: a case for inverse Compton scattering
• Fermi LAT observations of the Geminga pulsar
• Light-curve modelling constraints on the obliquities and aspect angles of the young Fermi pulsars
• PSR J0007+7303 in the CTA1 SNR: New Gamma-ray Results from Two Years of Fermi-LAT Observations
• Fermi-LAT Detection of Pulsed Gamma-rays Above 50 GeV from the Vela Pulsar
• An assessment of the pulsar outer gap model. I: Assumptions, uncertainties, and implications for the gap size and the accelerating field
• Modeling of the gamma-ray pulsed spectra of Geminga, Crab, and Vela with synchro-curvature radiation
• An assessment of the pulsar outer gap model. II: Implications for the predicted $\gamma$-ray spectra

Cited by in corpus (15)

• Magnetic, thermal and rotational evolution of isolated neutron stars
• Magnetic, thermal and rotational evolution of isolated neutron stars
• Order parameters for the high-energy spectra of pulsars
• Gamma-ray upper limits on magnetars with 6 years of Fermi-LAT observations
• Search for VHE gamma-ray emission from Geminga pulsar and nebula with the MAGIC telescopes
• Synchro-curvature modelling of the multi-frequency non-thermal emission of pulsars
• Observing and modeling the gamma-ray emission from pulsar/pulsar wind nebula complex PSR J0205+6449/3C 58
• Gamma-ray emission from PSR J0007+7303 using 7 years of Fermi Large Area Telescope observations
• Synchro-curvature emitting regions in high-energy pulsar models
• Efficiency of Synchrotron Radiation from Rotation-Powered Pulsars
• Theoretically motivated search and detection of non-thermal pulsations from PSRs J1747-2958, J2021+3651, and J1826-1256
• A novel approach for the analysis of the geometry involved in determining light curves of pulsars
• Dark neutron stars
• Investigating the emission signatures of pulsar halo candidate HESS J1813-126
• Inferring pulsar periods from synchro-curvature spectra