Modeling of the gamma-ray pulsed spectra of Geminga, Crab, and Vela with synchro-curvature radiation

Abstract

$\gamma$-ray spectra of pulsars have been mostly studied in a phenomenological way, by fitting them to a cut-off power-law function. Here, we analyze a model where pulsed emission comes from synchro-curvature processes in a gap. We calculate the variation of kinetic energy of magnetospheric particles along the gap and the associated radiated spectra, considering an effective particle distribution. We fit the phase-averaged and phase-resolved Fermi-LAT spectra of the three brightest gamma-ray pulsars: Geminga, Crab, and Vela, and constrain the three free parameters we leave free in the model. Our best-fit models well reproduce the observed data, apart from residuals above a few GeV in some cases, range for which the inverse Compton scattering likely becomes the dominant mechanism. In any case, the flat slope at low-energy (< GeV) seen by Fermi-LAT both in the phase-averaged and phase-resolved spectra of most pulsars, including the ones we studied, requires that most of the detected radiation below ~ GeV is produced during the beginning of the particle trajectories, when radiation mostly come from the loss of perpendicular momentum.

arXiv comment11 pages, 9 figures, 2 tables. Published in MNRAS main journal

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• Synchro-curvature modelling of the multi-frequency non-thermal emission of pulsars
• Probing gamma-ray emissions of Fermi-LAT pulsars with a non-stationary outer gap model
• Observing and modeling the gamma-ray emission from pulsar/pulsar wind nebula complex PSR J0205+6449/3C 58
• A systematic synchro-curvature modelling of pulsar $\gamma$-ray spectra unveils hidden trends
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• Synchro-curvature emitting regions in high-energy pulsar models
• Efficiency of Synchrotron Radiation from Rotation-Powered Pulsars
• A novel approach for the analysis of the geometry involved in determining light curves of pulsars
• Dissecting the emission from LHAASO J0341+5258: implications for future multi-wavelength observations
• Pulsar striped winds
• Prospects for the characterization of the VHE emission from the Crab Nebula and Pulsar with the Cherenkov Telescope Array
• Energy release from magnetospheres deformed by gravitational waves
• Inferring pulsar periods from synchro-curvature spectra