High-resolution radio study of SNR IC 443 at low radio frequencies

Autores
Castelletti, G.; Dubner, G.; Clarke, T.; Kassim, N.E.
Año de publicación
2011
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Aims.We investigate the morphology at low radio frequencies of the supernova remnant (SNR) IC 443 in detail and accurately establish its radio continuum spectral properties. Methods. We used the VLA in multiple configurations to produce high-resolution radio images of IC 443 at 74 and 330 MHz. From these data we produced the first sensitive, spatially resolved spectral analysis of the radio emission at long wavelengths. The changes with position in the radio spectral index were correlated with data in near infrared (NIR) from 2MASS, in gamma-rays from VERITAS, and with the molecular 12CO (J = 1-0) line emission. Results. The new image at 74 MHz has HPBW = 35′′ and rms = 30 mJy beam-1 and at 330 MHz HPBW = 17′′and rms = 1.7 mJy beam-1. The integrated flux densities for the whole SNR are S SNR 74MHz = 470 ± 51 Jy and S SNR 330MHz = 248 ± 15 Jy. Improved estimates of the integrated spectrum were derived taking a turnover into account to fit the lowest frequency measurements in the literature. Combining our measurements with existing data, we derive an integrated spectral index α 10700MHz 10MHz =-0.39 ± 0.01 with a free-free continuum optical depth at 330 MHz 330 ∼ 7 × 10 -4 (τ10 = 1.07); all measurements above ∼10 MHz are equally consistent with a power law spectrum. For the pulsar wind nebula associated with the compact source CXOU J061705.3+222127, we calculated S PWN 330MHz = 0.23±0.05 Jy, SPWN 1420MHz = 0.20±0.04 Jy, and α8460MHz 330MHz ∼ 0.0. Substantial variations are observed in spectral index between 74 and 330 MHz across IC 443. The flattest spectral components (-0.25 = a =-0.05) coincide with the brightest parts of the SNR along the eastern border, with an impressive agreement with ionic lines as observed in the 2MASS J and H bands. The diffuse interior of IC 443 has a spectrum steeper than found anywhere in the SNR (-0.85 = a =-0.6), while the southern ridge again has a flatter spectrum (a ∼-0.4). With the available statistics the VERITAS .-ray emission strikingly matches the CO distribution, but no clear evidence is found for a morphological correlation between the TeV distribution and radio emission. Conclusions. The excellent correspondence between the eastern radio flattest spectrum region and NIR ionic lines strongly suggests that the passage of a fast, dissociating J-type shock across the interacting molecular cloud dissociated the molecules and ionized the gas.We therefore conclude that thermal absorption at 74 MHz (τ74 up to ∼0.3) is responsible for the localized spectral index flattening observed along the eastern border of IC 443. Towards the interior of IC 443, the spectrum is consistent with those expected from linear diffusive shock acceleration, while the flatter spectrum in the southern ridge is a consequence of the strong shock/molecular cloud interaction. © 2011 ESO.
Fil:Castelletti, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Dubner, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fuente
Astron. Astrophys. 2011;534
Materia
gamma rays: ISM
infrared: ISM
ISM: clouds
ISM: individual objects: IC 443
ISM: supernova remnants
radio continuum: ISM
Absorption spectroscopy
Gamma rays
Infrared devices
Integrated circuits
Radio waves
Spectrum analysis
Supernovae
Tellurium compounds
Timing circuits
Gamma rays: isms
Infrared: ISM
ISM : clouds
ISM: individual objects
ISM: supernova remnants
Radio continuum: ISM
Atmospheric optics
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by/2.5/ar
Repositorio
Biblioteca Digital (UBA-FCEN)
Institución
Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
OAI Identificador
paperaa:paper_00046361_v534_n_p_Castelletti

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oai_identifier_str paperaa:paper_00046361_v534_n_p_Castelletti
network_acronym_str BDUBAFCEN
repository_id_str 1896
network_name_str Biblioteca Digital (UBA-FCEN)
spelling High-resolution radio study of SNR IC 443 at low radio frequenciesCastelletti, G.Dubner, G.Clarke, T.Kassim, N.E.gamma rays: ISMinfrared: ISMISM: cloudsISM: individual objects: IC 443ISM: supernova remnantsradio continuum: ISMAbsorption spectroscopyGamma raysInfrared devicesIntegrated circuitsRadio wavesSpectrum analysisSupernovaeTellurium compoundsTiming circuitsGamma rays: ismsInfrared: ISMISM : cloudsISM: individual objectsISM: supernova remnantsRadio continuum: ISMAtmospheric opticsAims.We investigate the morphology at low radio frequencies of the supernova remnant (SNR) IC 443 in detail and accurately establish its radio continuum spectral properties. Methods. We used the VLA in multiple configurations to produce high-resolution radio images of IC 443 at 74 and 330 MHz. From these data we produced the first sensitive, spatially resolved spectral analysis of the radio emission at long wavelengths. The changes with position in the radio spectral index were correlated with data in near infrared (NIR) from 2MASS, in gamma-rays from VERITAS, and with the molecular 12CO (J = 1-0) line emission. Results. The new image at 74 MHz has HPBW = 35′′ and rms = 30 mJy beam-1 and at 330 MHz HPBW = 17′′and rms = 1.7 mJy beam-1. The integrated flux densities for the whole SNR are S SNR 74MHz = 470 ± 51 Jy and S SNR 330MHz = 248 ± 15 Jy. Improved estimates of the integrated spectrum were derived taking a turnover into account to fit the lowest frequency measurements in the literature. Combining our measurements with existing data, we derive an integrated spectral index α 10700MHz 10MHz =-0.39 ± 0.01 with a free-free continuum optical depth at 330 MHz 330 ∼ 7 × 10 -4 (τ10 = 1.07); all measurements above ∼10 MHz are equally consistent with a power law spectrum. For the pulsar wind nebula associated with the compact source CXOU J061705.3+222127, we calculated S PWN 330MHz = 0.23±0.05 Jy, SPWN 1420MHz = 0.20±0.04 Jy, and α8460MHz 330MHz ∼ 0.0. Substantial variations are observed in spectral index between 74 and 330 MHz across IC 443. The flattest spectral components (-0.25 = a =-0.05) coincide with the brightest parts of the SNR along the eastern border, with an impressive agreement with ionic lines as observed in the 2MASS J and H bands. The diffuse interior of IC 443 has a spectrum steeper than found anywhere in the SNR (-0.85 = a =-0.6), while the southern ridge again has a flatter spectrum (a ∼-0.4). With the available statistics the VERITAS .-ray emission strikingly matches the CO distribution, but no clear evidence is found for a morphological correlation between the TeV distribution and radio emission. Conclusions. The excellent correspondence between the eastern radio flattest spectrum region and NIR ionic lines strongly suggests that the passage of a fast, dissociating J-type shock across the interacting molecular cloud dissociated the molecules and ionized the gas.We therefore conclude that thermal absorption at 74 MHz (τ74 up to ∼0.3) is responsible for the localized spectral index flattening observed along the eastern border of IC 443. Towards the interior of IC 443, the spectrum is consistent with those expected from linear diffusive shock acceleration, while the flatter spectrum in the southern ridge is a consequence of the strong shock/molecular cloud interaction. © 2011 ESO.Fil:Castelletti, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Dubner, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.2011info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfhttp://hdl.handle.net/20.500.12110/paper_00046361_v534_n_p_CastellettiAstron. Astrophys. 2011;534reponame:Biblioteca Digital (UBA-FCEN)instname:Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturalesinstacron:UBA-FCENenginfo:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by/2.5/ar2025-09-29T13:43:05Zpaperaa:paper_00046361_v534_n_p_CastellettiInstitucionalhttps://digital.bl.fcen.uba.ar/Universidad públicaNo correspondehttps://digital.bl.fcen.uba.ar/cgi-bin/oaiserver.cgiana@bl.fcen.uba.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:18962025-09-29 13:43:06.871Biblioteca Digital (UBA-FCEN) - Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturalesfalse
dc.title.none.fl_str_mv High-resolution radio study of SNR IC 443 at low radio frequencies
title High-resolution radio study of SNR IC 443 at low radio frequencies
spellingShingle High-resolution radio study of SNR IC 443 at low radio frequencies
Castelletti, G.
gamma rays: ISM
infrared: ISM
ISM: clouds
ISM: individual objects: IC 443
ISM: supernova remnants
radio continuum: ISM
Absorption spectroscopy
Gamma rays
Infrared devices
Integrated circuits
Radio waves
Spectrum analysis
Supernovae
Tellurium compounds
Timing circuits
Gamma rays: isms
Infrared: ISM
ISM : clouds
ISM: individual objects
ISM: supernova remnants
Radio continuum: ISM
Atmospheric optics
title_short High-resolution radio study of SNR IC 443 at low radio frequencies
title_full High-resolution radio study of SNR IC 443 at low radio frequencies
title_fullStr High-resolution radio study of SNR IC 443 at low radio frequencies
title_full_unstemmed High-resolution radio study of SNR IC 443 at low radio frequencies
title_sort High-resolution radio study of SNR IC 443 at low radio frequencies
dc.creator.none.fl_str_mv Castelletti, G.
Dubner, G.
Clarke, T.
Kassim, N.E.
author Castelletti, G.
author_facet Castelletti, G.
Dubner, G.
Clarke, T.
Kassim, N.E.
author_role author
author2 Dubner, G.
Clarke, T.
Kassim, N.E.
author2_role author
author
author
dc.subject.none.fl_str_mv gamma rays: ISM
infrared: ISM
ISM: clouds
ISM: individual objects: IC 443
ISM: supernova remnants
radio continuum: ISM
Absorption spectroscopy
Gamma rays
Infrared devices
Integrated circuits
Radio waves
Spectrum analysis
Supernovae
Tellurium compounds
Timing circuits
Gamma rays: isms
Infrared: ISM
ISM : clouds
ISM: individual objects
ISM: supernova remnants
Radio continuum: ISM
Atmospheric optics
topic gamma rays: ISM
infrared: ISM
ISM: clouds
ISM: individual objects: IC 443
ISM: supernova remnants
radio continuum: ISM
Absorption spectroscopy
Gamma rays
Infrared devices
Integrated circuits
Radio waves
Spectrum analysis
Supernovae
Tellurium compounds
Timing circuits
Gamma rays: isms
Infrared: ISM
ISM : clouds
ISM: individual objects
ISM: supernova remnants
Radio continuum: ISM
Atmospheric optics
dc.description.none.fl_txt_mv Aims.We investigate the morphology at low radio frequencies of the supernova remnant (SNR) IC 443 in detail and accurately establish its radio continuum spectral properties. Methods. We used the VLA in multiple configurations to produce high-resolution radio images of IC 443 at 74 and 330 MHz. From these data we produced the first sensitive, spatially resolved spectral analysis of the radio emission at long wavelengths. The changes with position in the radio spectral index were correlated with data in near infrared (NIR) from 2MASS, in gamma-rays from VERITAS, and with the molecular 12CO (J = 1-0) line emission. Results. The new image at 74 MHz has HPBW = 35′′ and rms = 30 mJy beam-1 and at 330 MHz HPBW = 17′′and rms = 1.7 mJy beam-1. The integrated flux densities for the whole SNR are S SNR 74MHz = 470 ± 51 Jy and S SNR 330MHz = 248 ± 15 Jy. Improved estimates of the integrated spectrum were derived taking a turnover into account to fit the lowest frequency measurements in the literature. Combining our measurements with existing data, we derive an integrated spectral index α 10700MHz 10MHz =-0.39 ± 0.01 with a free-free continuum optical depth at 330 MHz 330 ∼ 7 × 10 -4 (τ10 = 1.07); all measurements above ∼10 MHz are equally consistent with a power law spectrum. For the pulsar wind nebula associated with the compact source CXOU J061705.3+222127, we calculated S PWN 330MHz = 0.23±0.05 Jy, SPWN 1420MHz = 0.20±0.04 Jy, and α8460MHz 330MHz ∼ 0.0. Substantial variations are observed in spectral index between 74 and 330 MHz across IC 443. The flattest spectral components (-0.25 = a =-0.05) coincide with the brightest parts of the SNR along the eastern border, with an impressive agreement with ionic lines as observed in the 2MASS J and H bands. The diffuse interior of IC 443 has a spectrum steeper than found anywhere in the SNR (-0.85 = a =-0.6), while the southern ridge again has a flatter spectrum (a ∼-0.4). With the available statistics the VERITAS .-ray emission strikingly matches the CO distribution, but no clear evidence is found for a morphological correlation between the TeV distribution and radio emission. Conclusions. The excellent correspondence between the eastern radio flattest spectrum region and NIR ionic lines strongly suggests that the passage of a fast, dissociating J-type shock across the interacting molecular cloud dissociated the molecules and ionized the gas.We therefore conclude that thermal absorption at 74 MHz (τ74 up to ∼0.3) is responsible for the localized spectral index flattening observed along the eastern border of IC 443. Towards the interior of IC 443, the spectrum is consistent with those expected from linear diffusive shock acceleration, while the flatter spectrum in the southern ridge is a consequence of the strong shock/molecular cloud interaction. © 2011 ESO.
Fil:Castelletti, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Dubner, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
description Aims.We investigate the morphology at low radio frequencies of the supernova remnant (SNR) IC 443 in detail and accurately establish its radio continuum spectral properties. Methods. We used the VLA in multiple configurations to produce high-resolution radio images of IC 443 at 74 and 330 MHz. From these data we produced the first sensitive, spatially resolved spectral analysis of the radio emission at long wavelengths. The changes with position in the radio spectral index were correlated with data in near infrared (NIR) from 2MASS, in gamma-rays from VERITAS, and with the molecular 12CO (J = 1-0) line emission. Results. The new image at 74 MHz has HPBW = 35′′ and rms = 30 mJy beam-1 and at 330 MHz HPBW = 17′′and rms = 1.7 mJy beam-1. The integrated flux densities for the whole SNR are S SNR 74MHz = 470 ± 51 Jy and S SNR 330MHz = 248 ± 15 Jy. Improved estimates of the integrated spectrum were derived taking a turnover into account to fit the lowest frequency measurements in the literature. Combining our measurements with existing data, we derive an integrated spectral index α 10700MHz 10MHz =-0.39 ± 0.01 with a free-free continuum optical depth at 330 MHz 330 ∼ 7 × 10 -4 (τ10 = 1.07); all measurements above ∼10 MHz are equally consistent with a power law spectrum. For the pulsar wind nebula associated with the compact source CXOU J061705.3+222127, we calculated S PWN 330MHz = 0.23±0.05 Jy, SPWN 1420MHz = 0.20±0.04 Jy, and α8460MHz 330MHz ∼ 0.0. Substantial variations are observed in spectral index between 74 and 330 MHz across IC 443. The flattest spectral components (-0.25 = a =-0.05) coincide with the brightest parts of the SNR along the eastern border, with an impressive agreement with ionic lines as observed in the 2MASS J and H bands. The diffuse interior of IC 443 has a spectrum steeper than found anywhere in the SNR (-0.85 = a =-0.6), while the southern ridge again has a flatter spectrum (a ∼-0.4). With the available statistics the VERITAS .-ray emission strikingly matches the CO distribution, but no clear evidence is found for a morphological correlation between the TeV distribution and radio emission. Conclusions. The excellent correspondence between the eastern radio flattest spectrum region and NIR ionic lines strongly suggests that the passage of a fast, dissociating J-type shock across the interacting molecular cloud dissociated the molecules and ionized the gas.We therefore conclude that thermal absorption at 74 MHz (τ74 up to ∼0.3) is responsible for the localized spectral index flattening observed along the eastern border of IC 443. Towards the interior of IC 443, the spectrum is consistent with those expected from linear diffusive shock acceleration, while the flatter spectrum in the southern ridge is a consequence of the strong shock/molecular cloud interaction. © 2011 ESO.
publishDate 2011
dc.date.none.fl_str_mv 2011
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/20.500.12110/paper_00046361_v534_n_p_Castelletti
url http://hdl.handle.net/20.500.12110/paper_00046361_v534_n_p_Castelletti
dc.language.none.fl_str_mv eng
language eng
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/2.5/ar
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by/2.5/ar
dc.format.none.fl_str_mv application/pdf
dc.source.none.fl_str_mv Astron. Astrophys. 2011;534
reponame:Biblioteca Digital (UBA-FCEN)
instname:Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
instacron:UBA-FCEN
reponame_str Biblioteca Digital (UBA-FCEN)
collection Biblioteca Digital (UBA-FCEN)
instname_str Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
instacron_str UBA-FCEN
institution UBA-FCEN
repository.name.fl_str_mv Biblioteca Digital (UBA-FCEN) - Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
repository.mail.fl_str_mv ana@bl.fcen.uba.ar
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