The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration

Autores
Cardillo, M.; Tavani, M.; Giuliani, A.; Yoshiike, S.; Sano, H.; Fukuda, T.; Fukui, Y.; Castelletti, Gabriela Marta; Dubner, Gloria Mabel
Año de publicación
2014
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
The middle-aged supernova remnant (SNR) W44 has recently attracted attention because of its relevance regarding the origin of Galactic cosmic-rays. The gamma-ray missions AGILE and Fermi have established, for the first time for a SNR, the spectral continuum below 200 MeV which can be attributed to neutral pion emission. Confirming the hadronic origin of the gamma-ray emission near 100 MeV is then of the greatest importance. Our paper is focused on a global re-assessment of all available data and models of particle acceleration in W44, with the goal of determining on a firm ground the hadronic and leptonic contributions to the overall spectrum. We also present new gamma-ray and CO NANTEN2 data on W44, and compare them with recently published AGILE and Fermi data. Our analysis strengthens previous studies and observations of the W44 complex environment and provides new information for a more detailed modeling. In particular, we determine that the average gas density of the regions emitting 100 MeV - 10 GeV gamma-rays is relatively high (n= 250 - 300 cm^-3). The hadronic interpretation of the gamma-ray spectrum of W44 is viable, and supported by strong evidence. It implies a relatively large value for the average magnetic field (B > 10^2 microG) in the SNR surroundings, sign of field amplification by shock-driven turbulence. Our new analysis establishes that the spectral index of the proton energy distribution function is p1 = 2.2 +/- 0.1 at low energies and p2 = 3.2 +/- 0.1 at high energies. We critically discuss hadronic versus leptonic-only models of emission taking into account simultaneously radio and gamma-ray data. We find that the leptonic models are disfavored by the combination of radio and gamma-ray data. Having determined the hadronic nature of the gamma-ray emission on firm ground, a number of theoretical challenges remains to be addressed.
Fil: Cardillo, M.. INAF/IAPS; Italia. Universita Tor Vergata; Italia
Fil: Tavani, M.. Universita Tor Vergata; Italia. INAF/IAPS; Italia. CIFS-Torino; Italia
Fil: Giuliani, A.. INAF/IASF-Milano; Italia. CIFS-Torino; Italia
Fil: Yoshiike, S.. Nagoya University; Japón
Fil: Sano, H.. Nagoya University; Japón
Fil: Fukuda, T.. Nagoya University; Japón
Fil: Fukui, Y.. Nagoya University; Japón
Fil: Castelletti, Gabriela Marta. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
Fil: Dubner, Gloria Mabel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
Materia
acceleration of particles
astroparticle physics
shock waves
Supernova Remnants, gamma-rays
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/16496
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/16496
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling The Supernova Remnant W44: confirmations and challenges for cosmic-ray accelerationCardillo, M.Tavani, M.Giuliani, A.Yoshiike, S.Sano, H.Fukuda, T.Fukui, Y.Castelletti, Gabriela MartaDubner, Gloria Mabelacceleration of particlesastroparticle physicsshock wavesSupernova Remnants, gamma-rayshttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1The middle-aged supernova remnant (SNR) W44 has recently attracted attention because of its relevance regarding the origin of Galactic cosmic-rays. The gamma-ray missions AGILE and Fermi have established, for the first time for a SNR, the spectral continuum below 200 MeV which can be attributed to neutral pion emission. Confirming the hadronic origin of the gamma-ray emission near 100 MeV is then of the greatest importance. Our paper is focused on a global re-assessment of all available data and models of particle acceleration in W44, with the goal of determining on a firm ground the hadronic and leptonic contributions to the overall spectrum. We also present new gamma-ray and CO NANTEN2 data on W44, and compare them with recently published AGILE and Fermi data. Our analysis strengthens previous studies and observations of the W44 complex environment and provides new information for a more detailed modeling. In particular, we determine that the average gas density of the regions emitting 100 MeV - 10 GeV gamma-rays is relatively high (n= 250 - 300 cm^-3). The hadronic interpretation of the gamma-ray spectrum of W44 is viable, and supported by strong evidence. It implies a relatively large value for the average magnetic field (B > 10^2 microG) in the SNR surroundings, sign of field amplification by shock-driven turbulence. Our new analysis establishes that the spectral index of the proton energy distribution function is p1 = 2.2 +/- 0.1 at low energies and p2 = 3.2 +/- 0.1 at high energies. We critically discuss hadronic versus leptonic-only models of emission taking into account simultaneously radio and gamma-ray data. We find that the leptonic models are disfavored by the combination of radio and gamma-ray data. Having determined the hadronic nature of the gamma-ray emission on firm ground, a number of theoretical challenges remains to be addressed.Fil: Cardillo, M.. INAF/IAPS; Italia. Universita Tor Vergata; ItaliaFil: Tavani, M.. Universita Tor Vergata; Italia. INAF/IAPS; Italia. CIFS-Torino; ItaliaFil: Giuliani, A.. INAF/IASF-Milano; Italia. CIFS-Torino; ItaliaFil: Yoshiike, S.. Nagoya University; JapónFil: Sano, H.. Nagoya University; JapónFil: Fukuda, T.. Nagoya University; JapónFil: Fukui, Y.. Nagoya University; JapónFil: Castelletti, Gabriela Marta. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Dubner, Gloria Mabel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaEdp Sciences2014-03info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/16496Cardillo, M.; Tavani, M.; Giuliani, A.; Yoshiike, S.; Sano, H.; et al.; The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration; Edp Sciences; Astronomy And Astrophysics; 565; 3-2014; 74-860004-6361enginfo:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201322685info:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/articles/aa/abs/2014/05/aa22685-13/aa22685-13.htmlinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T09:47:30Zoai:ri.conicet.gov.ar:11336/16496instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 09:47:30.448CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration
title The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration
spellingShingle The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration
Cardillo, M.
acceleration of particles
astroparticle physics
shock waves
Supernova Remnants, gamma-rays
title_short The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration
title_full The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration
title_fullStr The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration
title_full_unstemmed The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration
title_sort The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration
dc.creator.none.fl_str_mv Cardillo, M.
Tavani, M.
Giuliani, A.
Yoshiike, S.
Sano, H.
Fukuda, T.
Fukui, Y.
Castelletti, Gabriela Marta
Dubner, Gloria Mabel
author Cardillo, M.
author_facet Cardillo, M.
Tavani, M.
Giuliani, A.
Yoshiike, S.
Sano, H.
Fukuda, T.
Fukui, Y.
Castelletti, Gabriela Marta
Dubner, Gloria Mabel
author_role author
author2 Tavani, M.
Giuliani, A.
Yoshiike, S.
Sano, H.
Fukuda, T.
Fukui, Y.
Castelletti, Gabriela Marta
Dubner, Gloria Mabel
author2_role author
author
author
author
author
author
author
author
dc.subject.none.fl_str_mv acceleration of particles
astroparticle physics
shock waves
Supernova Remnants, gamma-rays
topic acceleration of particles
astroparticle physics
shock waves
Supernova Remnants, gamma-rays
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv The middle-aged supernova remnant (SNR) W44 has recently attracted attention because of its relevance regarding the origin of Galactic cosmic-rays. The gamma-ray missions AGILE and Fermi have established, for the first time for a SNR, the spectral continuum below 200 MeV which can be attributed to neutral pion emission. Confirming the hadronic origin of the gamma-ray emission near 100 MeV is then of the greatest importance. Our paper is focused on a global re-assessment of all available data and models of particle acceleration in W44, with the goal of determining on a firm ground the hadronic and leptonic contributions to the overall spectrum. We also present new gamma-ray and CO NANTEN2 data on W44, and compare them with recently published AGILE and Fermi data. Our analysis strengthens previous studies and observations of the W44 complex environment and provides new information for a more detailed modeling. In particular, we determine that the average gas density of the regions emitting 100 MeV - 10 GeV gamma-rays is relatively high (n= 250 - 300 cm^-3). The hadronic interpretation of the gamma-ray spectrum of W44 is viable, and supported by strong evidence. It implies a relatively large value for the average magnetic field (B > 10^2 microG) in the SNR surroundings, sign of field amplification by shock-driven turbulence. Our new analysis establishes that the spectral index of the proton energy distribution function is p1 = 2.2 +/- 0.1 at low energies and p2 = 3.2 +/- 0.1 at high energies. We critically discuss hadronic versus leptonic-only models of emission taking into account simultaneously radio and gamma-ray data. We find that the leptonic models are disfavored by the combination of radio and gamma-ray data. Having determined the hadronic nature of the gamma-ray emission on firm ground, a number of theoretical challenges remains to be addressed.
Fil: Cardillo, M.. INAF/IAPS; Italia. Universita Tor Vergata; Italia
Fil: Tavani, M.. Universita Tor Vergata; Italia. INAF/IAPS; Italia. CIFS-Torino; Italia
Fil: Giuliani, A.. INAF/IASF-Milano; Italia. CIFS-Torino; Italia
Fil: Yoshiike, S.. Nagoya University; Japón
Fil: Sano, H.. Nagoya University; Japón
Fil: Fukuda, T.. Nagoya University; Japón
Fil: Fukui, Y.. Nagoya University; Japón
Fil: Castelletti, Gabriela Marta. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
Fil: Dubner, Gloria Mabel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
description The middle-aged supernova remnant (SNR) W44 has recently attracted attention because of its relevance regarding the origin of Galactic cosmic-rays. The gamma-ray missions AGILE and Fermi have established, for the first time for a SNR, the spectral continuum below 200 MeV which can be attributed to neutral pion emission. Confirming the hadronic origin of the gamma-ray emission near 100 MeV is then of the greatest importance. Our paper is focused on a global re-assessment of all available data and models of particle acceleration in W44, with the goal of determining on a firm ground the hadronic and leptonic contributions to the overall spectrum. We also present new gamma-ray and CO NANTEN2 data on W44, and compare them with recently published AGILE and Fermi data. Our analysis strengthens previous studies and observations of the W44 complex environment and provides new information for a more detailed modeling. In particular, we determine that the average gas density of the regions emitting 100 MeV - 10 GeV gamma-rays is relatively high (n= 250 - 300 cm^-3). The hadronic interpretation of the gamma-ray spectrum of W44 is viable, and supported by strong evidence. It implies a relatively large value for the average magnetic field (B > 10^2 microG) in the SNR surroundings, sign of field amplification by shock-driven turbulence. Our new analysis establishes that the spectral index of the proton energy distribution function is p1 = 2.2 +/- 0.1 at low energies and p2 = 3.2 +/- 0.1 at high energies. We critically discuss hadronic versus leptonic-only models of emission taking into account simultaneously radio and gamma-ray data. We find that the leptonic models are disfavored by the combination of radio and gamma-ray data. Having determined the hadronic nature of the gamma-ray emission on firm ground, a number of theoretical challenges remains to be addressed.
publishDate 2014
dc.date.none.fl_str_mv 2014-03
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/11336/16496
Cardillo, M.; Tavani, M.; Giuliani, A.; Yoshiike, S.; Sano, H.; et al.; The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration; Edp Sciences; Astronomy And Astrophysics; 565; 3-2014; 74-86
0004-6361
url http://hdl.handle.net/11336/16496
identifier_str_mv Cardillo, M.; Tavani, M.; Giuliani, A.; Yoshiike, S.; Sano, H.; et al.; The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration; Edp Sciences; Astronomy And Astrophysics; 565; 3-2014; 74-86
0004-6361
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201322685
info:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/articles/aa/abs/2014/05/aa22685-13/aa22685-13.html
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Edp Sciences
publisher.none.fl_str_mv Edp Sciences
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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score 13.070432

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