Query : 2020A&A...640A..43Y

2020A&A...640A..43Y - Astronomy and Astrophysics, volume 640A, 43-43 (2020/8-1)

Inferring the origins of the pulsed γ-ray emission from the Crab pulsar with ten-year Fermi-LAT data.


Abstract (from CDS):

Context. The Crab pulsar is a bright γ-ray source, which has been detected at photon energies up to ∼1 TeV. Its phase-averaged and phase-resolved γ-ray spectra below 10GeV exhibit exponential cutoffs, while those above 10GeV apparently follow simple power laws.
Aims. We re-visit the γ-ray properties of the Crab pulsar with ten-year Fermi Large Area Telescope (LAT) data in the range of 60 MeV-500GeV. With the phase-resolved spectra, we investigate the origins and mechanisms responsible for the emissions.
Methods. The phaseograms were reconstructed for different energy bands and further analysed using a wavelet decomposition. The phase-resolved energy spectra were combined with the observations of ground-based instruments, such as MAGIC and VERITAS, to achieve a larger energy converage. We fitted power-law models to the overlapping energy spectra from 10GeV to ∼1TeV. In the fit, we included a relative cross-calibration of energy scales between air-shower-based gamma-ray telescopes with the orbital pair-production telescope from the Fermi mission.
Results. We confirm the energy-dependence of the γ-ray pulse shape and, equivalently, the phase-dependence of the spectral shape for the Crab pulsar. A relatively sharp cutoff at a relatively high energy of ∼8GeV is observed for the bridge-phase emission. The E>10GeV spectrum observed for the second pulse peak is harder than those for other phases.
Conclusions. In view of the diversity of phase-resolved spectral shapes of the Crab pulsar, we tentatively propose a multi-origin scenario where the polar-cap, outer-gap, and relativistic-wind regions are involved.

Abstract Copyright: © ESO 2020

Journal keyword(s): pulsars: individual: Crab pulsar - gamma rays: stars

VizieR on-line data: <Available at CDS (J/A+A/640/A43): fig1.dat fig3.dat fig4.dat fig9.dat>

Errata: erratum vol. 649, art. C1 (2021)

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
1 3FGL J0534.5+2201s gam 05 34 32 +22 01.2           ~ 7 1
2 V* CM Tau Psr 05 34 31.9474694616 +22 00 52.153698024           ~ 5074 0
3 M 1 SNR 05 34 32 +22 00.8           ~ 5955 1
4 NAME Geminga Psr 06 33 54.153 +17 46 12.91           ~ 1154 0
5 NAME Vela Pulsar Psr 08 35 20.65525 -45 10 35.1545     15.10     ~ 2219 1

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