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Title: EVOLUTION OF HIGH-ENERGY PARTICLE DISTRIBUTION IN MATURE SHELL-TYPE SUPERNOVA REMNANTS

Abstract

Multi-wavelength observations of mature supernova remnants (SNRs), especially with recent advances in γ -ray astronomy, make it possible to constrain energy distribution of energetic particles within these remnants. In consideration of the SNR origin of Galactic cosmic rays and physics related to particle acceleration and radiative processes, we use a simple one-zone model to fit the nonthermal emission spectra of three shell-type SNRs located within 2° on the sky: RX J1713.7−3946, CTB 37B, and CTB 37A. Although radio images of these three sources all show a shell (or half-shell) structure, their radio, X-ray, and γ -ray spectra are quite different, offering an ideal case to explore evolution of energetic particle distribution in SNRs. Our spectral fitting shows that (1) the particle distribution becomes harder with aging of these SNRs, implying a continuous acceleration process, and the particle distributions of CTB 37A and CTB 37B in the GeV range are harder than the hardest distribution that can be produced at a shock via the linear diffusive shock particle acceleration process, so spatial transport may play a role; (2) the energy loss timescale of electrons at the high-energy cutoff due to synchrotron radiation appears to be always a bit (within a factormore » of a few) shorter than the age of the corresponding remnant, which also requires continuous particle acceleration; (3) double power-law distributions are needed to fit the spectra of CTB 37B and CTB 37A, which may be attributed to shock interaction with molecular clouds.« less

Authors:
; ; ;  [1];  [2];  [3]
  1. Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)
  2. University of Arizona, Tucson, Arizona, 85721 (United States)
  3. Key Laboratory of Astroparticle Physics of Yunnan Province, Kunming, 650091 (China)
Publication Date:
OSTI Identifier:
22661362
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 834; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; AGING; CLOUDS; COSMIC RADIATION; EMISSION SPECTRA; ENERGY LOSSES; ENERGY SPECTRA; GAMMA ASTRONOMY; GAMMA RADIATION; GAMMA SPECTRA; GEV RANGE; IMAGES; MILKY WAY; SUPERNOVA REMNANTS; SYNCHROTRON RADIATION; WAVELENGTHS; X RADIATION

Citation Formats

Zeng, Houdun, Xin, Yuliang, Liu, Siming, Zhang, Shuinai, Jokipii, J. R., and Zhang, Li, E-mail: zhd@pmo.ac.cn, E-mail: liusm@pmo.ac.cn. EVOLUTION OF HIGH-ENERGY PARTICLE DISTRIBUTION IN MATURE SHELL-TYPE SUPERNOVA REMNANTS. United States: N. p., 2017. Web. doi:10.3847/1538-4357/834/2/153.
Zeng, Houdun, Xin, Yuliang, Liu, Siming, Zhang, Shuinai, Jokipii, J. R., & Zhang, Li, E-mail: zhd@pmo.ac.cn, E-mail: liusm@pmo.ac.cn. EVOLUTION OF HIGH-ENERGY PARTICLE DISTRIBUTION IN MATURE SHELL-TYPE SUPERNOVA REMNANTS. United States. doi:10.3847/1538-4357/834/2/153.
Zeng, Houdun, Xin, Yuliang, Liu, Siming, Zhang, Shuinai, Jokipii, J. R., and Zhang, Li, E-mail: zhd@pmo.ac.cn, E-mail: liusm@pmo.ac.cn. Tue . "EVOLUTION OF HIGH-ENERGY PARTICLE DISTRIBUTION IN MATURE SHELL-TYPE SUPERNOVA REMNANTS". United States. doi:10.3847/1538-4357/834/2/153.
@article{osti_22661362,
title = {EVOLUTION OF HIGH-ENERGY PARTICLE DISTRIBUTION IN MATURE SHELL-TYPE SUPERNOVA REMNANTS},
author = {Zeng, Houdun and Xin, Yuliang and Liu, Siming and Zhang, Shuinai and Jokipii, J. R. and Zhang, Li, E-mail: zhd@pmo.ac.cn, E-mail: liusm@pmo.ac.cn},
abstractNote = {Multi-wavelength observations of mature supernova remnants (SNRs), especially with recent advances in γ -ray astronomy, make it possible to constrain energy distribution of energetic particles within these remnants. In consideration of the SNR origin of Galactic cosmic rays and physics related to particle acceleration and radiative processes, we use a simple one-zone model to fit the nonthermal emission spectra of three shell-type SNRs located within 2° on the sky: RX J1713.7−3946, CTB 37B, and CTB 37A. Although radio images of these three sources all show a shell (or half-shell) structure, their radio, X-ray, and γ -ray spectra are quite different, offering an ideal case to explore evolution of energetic particle distribution in SNRs. Our spectral fitting shows that (1) the particle distribution becomes harder with aging of these SNRs, implying a continuous acceleration process, and the particle distributions of CTB 37A and CTB 37B in the GeV range are harder than the hardest distribution that can be produced at a shock via the linear diffusive shock particle acceleration process, so spatial transport may play a role; (2) the energy loss timescale of electrons at the high-energy cutoff due to synchrotron radiation appears to be always a bit (within a factor of a few) shorter than the age of the corresponding remnant, which also requires continuous particle acceleration; (3) double power-law distributions are needed to fit the spectra of CTB 37B and CTB 37A, which may be attributed to shock interaction with molecular clouds.},
doi = {10.3847/1538-4357/834/2/153},
journal = {Astrophysical Journal},
number = 2,
volume = 834,
place = {United States},
year = {Tue Jan 10 00:00:00 EST 2017},
month = {Tue Jan 10 00:00:00 EST 2017}
}