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
- 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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paperaa:paper_00046361_v534_n_p_Castelletti |
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Biblioteca Digital (UBA-FCEN) |
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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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