Cosmic-ray acceleration at the forward shock in Tycho's supernova remnant: Evidence from Chandra X-ray observations

We present evidence for cosmic-ray acceleration at the forward shock in Tycho's supernova remnant (SNR) from three X-ray observables: (1) the proximity of the contact discontinuity to the forward shock, or blast wave, (2) the morphology of the emission from the rim of Tycho, and (3) the spectra...

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Guardado en:
Detalles Bibliográficos
Publicado: 2005
Materias:
ISM: individual (Tycho)
Supernova remnants
Supernovae: general
X-rays: ISM
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v634_n1I_p376_Warren
http://hdl.handle.net/20.500.12110/paper_0004637X_v634_n1I_p376_Warren
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_0004637X_v634_n1I_p376_Warren
record_format dspace
spelling paper:paper_0004637X_v634_n1I_p376_Warren2023-06-08T14:28:51Z Cosmic-ray acceleration at the forward shock in Tycho's supernova remnant: Evidence from Chandra X-ray observations ISM: individual (Tycho) Supernova remnants Supernovae: general X-rays: ISM We present evidence for cosmic-ray acceleration at the forward shock in Tycho's supernova remnant (SNR) from three X-ray observables: (1) the proximity of the contact discontinuity to the forward shock, or blast wave, (2) the morphology of the emission from the rim of Tycho, and (3) the spectral nature of the rim emission. We determine the locations of the blast wave (BW), contact discontinuity (CD), and reverse shock (RS) around the rim of Tycho's supernova remnant using a principal component analysis and other methods applied to new Chandra data. The azimuthal-angle-averaged radius of the BW is 251″. For the CD and RS we find average radii of 241″ and 183″, respectively. Taking account of projection effects, we find ratios of 1:0.93 :0.70 (BW : CD : RS). We show these values to be inconsistent with adiabatic hydrodynamic models of SNR evolution. The CD : BW ratio can be explained if cosmic-ray acceleration of ions is occurring at the forward shock. The RS : BW ratio, as well as the strong Fe Kα emission from the Tycho ejecta, imply that the RS is not accelerating cosmic rays. We also extract radial profiles from ∼34% of the rim of Tycho and compare them to models of surface brightness profiles behind the BW for a purely thermal plasma with an adiabatic shock. The observed morphology of the rim is much more strongly peaked than predicted by the model, indicating that such thermal emission is implausible here. Spectral analysis also implies that the rim emission is nonthermal in nature, lending further support to the idea that Tycho 's forward shock is accelerating cosmic rays. © 2005. The American Astronomical Society. All rights reserved. 2005 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v634_n1I_p376_Warren http://hdl.handle.net/20.500.12110/paper_0004637X_v634_n1I_p376_Warren
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic ISM: individual (Tycho)
Supernova remnants
Supernovae: general
X-rays: ISM
spellingShingle ISM: individual (Tycho)
Supernova remnants
Supernovae: general
X-rays: ISM
Cosmic-ray acceleration at the forward shock in Tycho's supernova remnant: Evidence from Chandra X-ray observations
topic_facet ISM: individual (Tycho)
Supernova remnants
Supernovae: general
X-rays: ISM
description We present evidence for cosmic-ray acceleration at the forward shock in Tycho's supernova remnant (SNR) from three X-ray observables: (1) the proximity of the contact discontinuity to the forward shock, or blast wave, (2) the morphology of the emission from the rim of Tycho, and (3) the spectral nature of the rim emission. We determine the locations of the blast wave (BW), contact discontinuity (CD), and reverse shock (RS) around the rim of Tycho's supernova remnant using a principal component analysis and other methods applied to new Chandra data. The azimuthal-angle-averaged radius of the BW is 251″. For the CD and RS we find average radii of 241″ and 183″, respectively. Taking account of projection effects, we find ratios of 1:0.93 :0.70 (BW : CD : RS). We show these values to be inconsistent with adiabatic hydrodynamic models of SNR evolution. The CD : BW ratio can be explained if cosmic-ray acceleration of ions is occurring at the forward shock. The RS : BW ratio, as well as the strong Fe Kα emission from the Tycho ejecta, imply that the RS is not accelerating cosmic rays. We also extract radial profiles from ∼34% of the rim of Tycho and compare them to models of surface brightness profiles behind the BW for a purely thermal plasma with an adiabatic shock. The observed morphology of the rim is much more strongly peaked than predicted by the model, indicating that such thermal emission is implausible here. Spectral analysis also implies that the rim emission is nonthermal in nature, lending further support to the idea that Tycho 's forward shock is accelerating cosmic rays. © 2005. The American Astronomical Society. All rights reserved.
title Cosmic-ray acceleration at the forward shock in Tycho's supernova remnant: Evidence from Chandra X-ray observations
title_short Cosmic-ray acceleration at the forward shock in Tycho's supernova remnant: Evidence from Chandra X-ray observations
title_full Cosmic-ray acceleration at the forward shock in Tycho's supernova remnant: Evidence from Chandra X-ray observations
title_fullStr Cosmic-ray acceleration at the forward shock in Tycho's supernova remnant: Evidence from Chandra X-ray observations
title_full_unstemmed Cosmic-ray acceleration at the forward shock in Tycho's supernova remnant: Evidence from Chandra X-ray observations
title_sort cosmic-ray acceleration at the forward shock in tycho's supernova remnant: evidence from chandra x-ray observations
publishDate 2005
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v634_n1I_p376_Warren
http://hdl.handle.net/20.500.12110/paper_0004637X_v634_n1I_p376_Warren
_version_ 1768545534613651456

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