Broadband Photon Spectrum and its Radial Profile of Pulsar Wind Nebulae

Journal Article · Sat Apr 01 04:00:00 EDT 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA679B· OSTI ID:22869152

Ishizaki, Wataru; Asano, Katsuaki ^[1]; Tanaka, Shuta J. ^[2]; Terasawa, Toshio ^[3]

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1. Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa City, Chiba, 277-8582 (Japan)
2. Department of Physics, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Kobe, Hyogo, 658-8501 (Japan)
3. iTHES Research Group, RIKEN, Wako, Saitama 351-0198 (Japan)

The observed radial profiles of the X-ray emission from pulsar wind nebulae (PWNe) have been claimed to contradict the standard 1D steady model. However, the 1D model has not been tested to simultaneously reproduce the volume-integrated spectrum and the radial profile of the surface brightness. We revisit the 1D steady model and apply it to PWNe 3C 58 and G21.5−0.9. We find that the parameters of the pulsar wind, the radius of the termination shock r{sub s}, and magnetization σ greatly affect both the photon spectrum and radial profile of the emission. We have shown that the parameters constrained by the entire spectrum lead to an X-ray nebula smaller than the observed nebula. We have also tested the case that reproduces only the observations in X- and gamma-rays, ignoring the radio and optical components. In this case, there are parameter sets that reproduce both the spectrum and emission profile, but the advection time to the edge of the nebula becomes much smaller than the age. Our detailed discussion clarifies that the standard 1D steady model has severe difficulty to simultaneously reproduce both the volume-integrated spectrum and the surface brightness. This implies that the model should be improved by taking into account extra physical processes such as spatial diffusion of particles. Additionally, we calculate the surface brightness profile of the radio, optical, and TeV gamma-rays. The future observations in these wavelengths are also important to probe the spatial distributions of the relativistic plasma and the magnetic field of PWNe.

• OSTI ID: 22869152
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 838; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BRIGHTNESS
DIFFUSION
EMISSION
GAMMA RADIATION
MAGNETIC FIELDS
MAGNETIZATION
MAGNETOHYDRODYNAMICS
NEBULAE
PHOTONS
PULSARS
RELATIVISTIC PLASMA
SPATIAL DISTRIBUTION
SPECTRA
STARS
STELLAR WINDS
SURFACES
TEV RANGE
X RADIATION