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Title: HARD X-RAY EMISSIONS FROM CASSIOPEIA A OBSERVED BY INTEGRAL

Abstract

Cassiopeia A (Cas A), as the nearby young remnant of a core-collapse supernova, is the best candidate for astrophysical studies in supernova explosion and its environment. We studied the hard X-ray emission from Cas A using the 10 year data of INTEGRAL observations, and first detected non-thermal continuum emission from the source up to 220 keV. The {sup 44}Ti line emission at 68 and 78 keV is confirmed by our observations with a mean flux of ∼(2.2 ± 0.4) × 10{sup 5} ph cm{sup 2} s{sup 1}, corresponding to a {sup 44}Ti yield in Cas A of (1.3 ± 0.4) × 10{sup 4} M {sub ⊙}. The continuum emission from 3 to 500 keV can be fit with a thermal bremsstrahlung of kT ∼ 0.79 ± 0.08 keV plus a power-law model of Γ ∼ 3.13 ± 0.03. The non-thermal emission from Cas A is well fit by a power-law model without a cutoff up to 220 keV. This radiation characteristic is inconsistent with diffusive shock acceleration models with a remnant shock velocity of only 5000 km s{sup 1}. The central compact object in Cas A cannot significantly contribute to the emission above 80 keV. Some possible physical origins ofmore » the non-thermal emission above 80 keV from the remnant shock are discussed. We deduce that the asymmetrical supernova explosion scenario of Cas A is a promising scenario for the production of high-energy synchrotron radiation photons, where a portion of the ejecta with a velocity of ∼0.1 c and opening angle of ∼10° can account for the 100 keV emission, as is consistent with the “jet” observed in Cas A.« less

Authors:
 [1];  [2]
  1. National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China)
  2. Department of Astronomy, School of Physics and Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)
Publication Date:
OSTI Identifier:
22666107
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 825; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; ASTROPHYSICS; BREMSSTRAHLUNG; COSMIC RADIATION; EMISSION; EXPLOSIONS; HARD X RADIATION; KEV RANGE; SUPERNOVA REMNANTS; SYNCHROTRON RADIATION; TITANIUM 44; VELOCITY

Citation Formats

Wang, Wei, and Li, Zhuo. HARD X-RAY EMISSIONS FROM CASSIOPEIA A OBSERVED BY INTEGRAL. United States: N. p., 2016. Web. doi:10.3847/0004-637X/825/2/102.
Wang, Wei, & Li, Zhuo. HARD X-RAY EMISSIONS FROM CASSIOPEIA A OBSERVED BY INTEGRAL. United States. doi:10.3847/0004-637X/825/2/102.
Wang, Wei, and Li, Zhuo. Sun . "HARD X-RAY EMISSIONS FROM CASSIOPEIA A OBSERVED BY INTEGRAL". United States. doi:10.3847/0004-637X/825/2/102.
@article{osti_22666107,
title = {HARD X-RAY EMISSIONS FROM CASSIOPEIA A OBSERVED BY INTEGRAL},
author = {Wang, Wei and Li, Zhuo},
abstractNote = {Cassiopeia A (Cas A), as the nearby young remnant of a core-collapse supernova, is the best candidate for astrophysical studies in supernova explosion and its environment. We studied the hard X-ray emission from Cas A using the 10 year data of INTEGRAL observations, and first detected non-thermal continuum emission from the source up to 220 keV. The {sup 44}Ti line emission at 68 and 78 keV is confirmed by our observations with a mean flux of ∼(2.2 ± 0.4) × 10{sup 5} ph cm{sup 2} s{sup 1}, corresponding to a {sup 44}Ti yield in Cas A of (1.3 ± 0.4) × 10{sup 4} M {sub ⊙}. The continuum emission from 3 to 500 keV can be fit with a thermal bremsstrahlung of kT ∼ 0.79 ± 0.08 keV plus a power-law model of Γ ∼ 3.13 ± 0.03. The non-thermal emission from Cas A is well fit by a power-law model without a cutoff up to 220 keV. This radiation characteristic is inconsistent with diffusive shock acceleration models with a remnant shock velocity of only 5000 km s{sup 1}. The central compact object in Cas A cannot significantly contribute to the emission above 80 keV. Some possible physical origins of the non-thermal emission above 80 keV from the remnant shock are discussed. We deduce that the asymmetrical supernova explosion scenario of Cas A is a promising scenario for the production of high-energy synchrotron radiation photons, where a portion of the ejecta with a velocity of ∼0.1 c and opening angle of ∼10° can account for the 100 keV emission, as is consistent with the “jet” observed in Cas A.},
doi = {10.3847/0004-637X/825/2/102},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 825,
place = {United States},
year = {2016},
month = {7}
}