Building up the spectrum of cosmic rays in star-forming regions
- Autores
- Torres, Diego F.; Cillis, Analia Nilda; Lacki, Brian; Rephaeli, Joel
- Año de publicación
- 2012
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- The common approach to compute the cosmic ray distribution in a starburst galaxy or region is equivalent to assuming that at any point within that environment, there is an accelerator inputting cosmic rays at a reduced rate. This rate should be compatible with the overall volume-average injection, given by the total number of accelerators that were active during the starburst age. These assumptions seem reasonable, especially under the supposition of a homogeneous and isotropic distribution of accelerators. However, in this approach the temporal evolution of the superposed spectrum is not explicitly derived; rather, it is essentially assumed ab initio. Here, we test the validity of this approach by following the temporal evolution and spatial distribution of the superposed cosmic ray spectrum and compare our results with those from theoretical models that treat the starburst region as a single source. In the calorimetric limit (with no cosmic ray advection), homogeneity is reached (typically within 20 per cent) across most of the starburst region. However, values of centre-to-edge intensity ratios can amount to a factor of several. Differences between the common homogeneous assumption for the cosmic ray distribution and our models are larger in the case of two-zone geometries, such as a central nucleus with a surrounding disc. We have also found that the decay of the cosmic ray density following the duration of the starburst process is slow, and even approximately 1 Myr after the burst ends (for a gas density of 35 cm-3) it may still be within an order of magnitude of its peak value. Based on our simulations, it seems that the detection of a relatively hard spectrum up to the highest gamma-ray energies from nearby starburst galaxies favours a relatively small diffusion coefficient (i.e. long diffusion time) in the region where most of the emission originates.
Fil: Torres, Diego F.. Institució Catalana de Recerca i Estudis Avancats; España
Fil: Cillis, Analia Nilda. 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: Lacki, Brian. Institute for Advanced Study; Estados Unidos
Fil: Rephaeli, Joel. University of California; Estados Unidos - Materia
-
radiation mechanisms: non-thermal
cosmic rays
supernova remnants
starburst - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
- Repositorio
- Institución
- Consejo Nacional de Investigaciones Científicas y Técnicas
- OAI Identificador
- oai:ri.conicet.gov.ar:11336/19309
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Building up the spectrum of cosmic rays in star-forming regionsTorres, Diego F.Cillis, Analia NildaLacki, BrianRephaeli, Joelradiation mechanisms: non-thermalcosmic rayssupernova remnantsstarbursthttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1The common approach to compute the cosmic ray distribution in a starburst galaxy or region is equivalent to assuming that at any point within that environment, there is an accelerator inputting cosmic rays at a reduced rate. This rate should be compatible with the overall volume-average injection, given by the total number of accelerators that were active during the starburst age. These assumptions seem reasonable, especially under the supposition of a homogeneous and isotropic distribution of accelerators. However, in this approach the temporal evolution of the superposed spectrum is not explicitly derived; rather, it is essentially assumed ab initio. Here, we test the validity of this approach by following the temporal evolution and spatial distribution of the superposed cosmic ray spectrum and compare our results with those from theoretical models that treat the starburst region as a single source. In the calorimetric limit (with no cosmic ray advection), homogeneity is reached (typically within 20 per cent) across most of the starburst region. However, values of centre-to-edge intensity ratios can amount to a factor of several. Differences between the common homogeneous assumption for the cosmic ray distribution and our models are larger in the case of two-zone geometries, such as a central nucleus with a surrounding disc. We have also found that the decay of the cosmic ray density following the duration of the starburst process is slow, and even approximately 1 Myr after the burst ends (for a gas density of 35 cm-3) it may still be within an order of magnitude of its peak value. Based on our simulations, it seems that the detection of a relatively hard spectrum up to the highest gamma-ray energies from nearby starburst galaxies favours a relatively small diffusion coefficient (i.e. long diffusion time) in the region where most of the emission originates.Fil: Torres, Diego F.. Institució Catalana de Recerca i Estudis Avancats; EspañaFil: Cillis, Analia Nilda. 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: Lacki, Brian. Institute for Advanced Study; Estados UnidosFil: Rephaeli, Joel. University of California; Estados UnidosOxford University Press2012-06info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/19309Torres, Diego F.; Cillis, Analia Nilda; Lacki, Brian; Rephaeli, Joel; Building up the spectrum of cosmic rays in star-forming regions; Oxford University Press; Monthly Notices of the Royal Astronomical Society; 423; 1; 6-2012; 822-8300035-8711CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://academic.oup.com/mnras/article-lookup/doi/10.1111/j.1365-2966.2012.20920.xinfo:eu-repo/semantics/altIdentifier/doi/10.1111/j.1365-2966.2012.20920.xinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T09:42:02Zoai:ri.conicet.gov.ar:11336/19309instacron: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 09:42:03.129CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse |
dc.title.none.fl_str_mv |
Building up the spectrum of cosmic rays in star-forming regions |
title |
Building up the spectrum of cosmic rays in star-forming regions |
spellingShingle |
Building up the spectrum of cosmic rays in star-forming regions Torres, Diego F. radiation mechanisms: non-thermal cosmic rays supernova remnants starburst |
title_short |
Building up the spectrum of cosmic rays in star-forming regions |
title_full |
Building up the spectrum of cosmic rays in star-forming regions |
title_fullStr |
Building up the spectrum of cosmic rays in star-forming regions |
title_full_unstemmed |
Building up the spectrum of cosmic rays in star-forming regions |
title_sort |
Building up the spectrum of cosmic rays in star-forming regions |
dc.creator.none.fl_str_mv |
Torres, Diego F. Cillis, Analia Nilda Lacki, Brian Rephaeli, Joel |
author |
Torres, Diego F. |
author_facet |
Torres, Diego F. Cillis, Analia Nilda Lacki, Brian Rephaeli, Joel |
author_role |
author |
author2 |
Cillis, Analia Nilda Lacki, Brian Rephaeli, Joel |
author2_role |
author author author |
dc.subject.none.fl_str_mv |
radiation mechanisms: non-thermal cosmic rays supernova remnants starburst |
topic |
radiation mechanisms: non-thermal cosmic rays supernova remnants starburst |
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 common approach to compute the cosmic ray distribution in a starburst galaxy or region is equivalent to assuming that at any point within that environment, there is an accelerator inputting cosmic rays at a reduced rate. This rate should be compatible with the overall volume-average injection, given by the total number of accelerators that were active during the starburst age. These assumptions seem reasonable, especially under the supposition of a homogeneous and isotropic distribution of accelerators. However, in this approach the temporal evolution of the superposed spectrum is not explicitly derived; rather, it is essentially assumed ab initio. Here, we test the validity of this approach by following the temporal evolution and spatial distribution of the superposed cosmic ray spectrum and compare our results with those from theoretical models that treat the starburst region as a single source. In the calorimetric limit (with no cosmic ray advection), homogeneity is reached (typically within 20 per cent) across most of the starburst region. However, values of centre-to-edge intensity ratios can amount to a factor of several. Differences between the common homogeneous assumption for the cosmic ray distribution and our models are larger in the case of two-zone geometries, such as a central nucleus with a surrounding disc. We have also found that the decay of the cosmic ray density following the duration of the starburst process is slow, and even approximately 1 Myr after the burst ends (for a gas density of 35 cm-3) it may still be within an order of magnitude of its peak value. Based on our simulations, it seems that the detection of a relatively hard spectrum up to the highest gamma-ray energies from nearby starburst galaxies favours a relatively small diffusion coefficient (i.e. long diffusion time) in the region where most of the emission originates. Fil: Torres, Diego F.. Institució Catalana de Recerca i Estudis Avancats; España Fil: Cillis, Analia Nilda. 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: Lacki, Brian. Institute for Advanced Study; Estados Unidos Fil: Rephaeli, Joel. University of California; Estados Unidos |
description |
The common approach to compute the cosmic ray distribution in a starburst galaxy or region is equivalent to assuming that at any point within that environment, there is an accelerator inputting cosmic rays at a reduced rate. This rate should be compatible with the overall volume-average injection, given by the total number of accelerators that were active during the starburst age. These assumptions seem reasonable, especially under the supposition of a homogeneous and isotropic distribution of accelerators. However, in this approach the temporal evolution of the superposed spectrum is not explicitly derived; rather, it is essentially assumed ab initio. Here, we test the validity of this approach by following the temporal evolution and spatial distribution of the superposed cosmic ray spectrum and compare our results with those from theoretical models that treat the starburst region as a single source. In the calorimetric limit (with no cosmic ray advection), homogeneity is reached (typically within 20 per cent) across most of the starburst region. However, values of centre-to-edge intensity ratios can amount to a factor of several. Differences between the common homogeneous assumption for the cosmic ray distribution and our models are larger in the case of two-zone geometries, such as a central nucleus with a surrounding disc. We have also found that the decay of the cosmic ray density following the duration of the starburst process is slow, and even approximately 1 Myr after the burst ends (for a gas density of 35 cm-3) it may still be within an order of magnitude of its peak value. Based on our simulations, it seems that the detection of a relatively hard spectrum up to the highest gamma-ray energies from nearby starburst galaxies favours a relatively small diffusion coefficient (i.e. long diffusion time) in the region where most of the emission originates. |
publishDate |
2012 |
dc.date.none.fl_str_mv |
2012-06 |
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/11336/19309 Torres, Diego F.; Cillis, Analia Nilda; Lacki, Brian; Rephaeli, Joel; Building up the spectrum of cosmic rays in star-forming regions; Oxford University Press; Monthly Notices of the Royal Astronomical Society; 423; 1; 6-2012; 822-830 0035-8711 CONICET Digital CONICET |
url |
http://hdl.handle.net/11336/19309 |
identifier_str_mv |
Torres, Diego F.; Cillis, Analia Nilda; Lacki, Brian; Rephaeli, Joel; Building up the spectrum of cosmic rays in star-forming regions; Oxford University Press; Monthly Notices of the Royal Astronomical Society; 423; 1; 6-2012; 822-830 0035-8711 CONICET Digital CONICET |
dc.language.none.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
info:eu-repo/semantics/altIdentifier/url/https://academic.oup.com/mnras/article-lookup/doi/10.1111/j.1365-2966.2012.20920.x info:eu-repo/semantics/altIdentifier/doi/10.1111/j.1365-2966.2012.20920.x |
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 application/pdf |
dc.publisher.none.fl_str_mv |
Oxford University Press |
publisher.none.fl_str_mv |
Oxford University Press |
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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13.070432 |