Capture of field stars by dark substructures

We use analytical and N-body methods to study the capture of field stars by gravitating substructures moving across a galactic environment. The majority of stars captured by a substructure mo v e on temporarily bound orbits that are lost to galactic tides after a few orbital revolutions. In numerica...

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Detalles Bibliográficos
Autores: Peñarrubia, Jorge, Errani, Raphaël, Walker, Alistair R., Gieles, Mark, Boekholt, Tjarda C. N.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2024
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/371534
Acceso en línea:http://hdl.handle.net/10261/371534
Access Level:acceso abierto
Palabra clave:Galaxy: kinematics and dynamics
Galaxies: evolution
Cosmology: dark matter
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spelling Capture of field stars by dark substructuresPeñarrubia, JorgeErrani, RaphaëlWalker, Alistair R.Gieles, MarkBoekholt, Tjarda C. N.Galaxy: kinematics and dynamicsGalaxies: evolutionCosmology: dark matterWe use analytical and N-body methods to study the capture of field stars by gravitating substructures moving across a galactic environment. The majority of stars captured by a substructure mo v e on temporarily bound orbits that are lost to galactic tides after a few orbital revolutions. In numerical experiments where a substructure model is immersed into a sea of field particles on a circular orbit, we find a population of particles that remain bound to the substructure potential for indefinitely long times. This population is absent from substructure models, initially placed outside the galaxy on an eccentric orbit. We show that gravitational capture is most efficient in dwarf spheroidal galaxies (dSphs) on account of their low velocity dispersions and high stellar phase-space densities. In these galaxies, ‘dark’ sub-subhaloes, which do not experience in situ star formation, may capture f ield stars and become visible as stellar o v erdensities with unusual properties: (i) they would have a large size for their luminosity, (ii) contain stellar populations indistinguishable from the host galaxy, and (iii) exhibit dark matter (DM)-dominated mass-to- light ratios. We discuss the nature of several ‘anomalous’ stellar systems reported as star clusters in the Fornax and Eridanus II dSphs that exhibit some of these characteristics. DM sub-subhaloes with a mass function d N/ d M • ∼ M −α • are expected to generate stellar systems with a luminosity function, d N/ d M ∼ M −β , where β = (2 α + 1) / 3 = 1 . 6 for α = 1 . 9. Detecting and characterizing these objects in dSphs would provide unprecedented constraints on the particle mass and cross-section of a large range of DM particle candidates.MGW acknowledges support from National Science Foundation (NSF) grants AST-1813881, AST-1909584 and AST-2206046. MG acknowledges financial support from the grants PID2021-125485NB-C22, EUR2020-112157, CEX2019-000918-M funded by MCIN/AEI/10.13039/501100011033 (State Agency for Research of the Spanish Ministry of Science and Innovation) and SGR-2021-01069 (AGAUR). RE acknowledges support from the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation programme (grant agreement number 834148), and from the National Science Foundation (NSF) grant AST-2206046. TB’s research was supported by an appointment to the NASA Postdoctoral Program at the NASA Ames Research Center, administered by Oak Ridge Associated Universities under contract with NASA.With funding from the Spanish government through the "Unit of Excellence Maria de Maeztu" accreditation (CEX2019-000918-M).Peer reviewedOxford University PressNational Science Foundation (US)Agencia Estatal de Investigación (España)Ministerio de Ciencia, Innovación y Universidades (España)Generalitat de CatalunyaEuropean CommissionEuropean Research CouncilNASAConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]202420242024info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionapplication/pdfhttp://hdl.handle.net/10261/371534reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2021-2023/PID2021-125485NB-C22info:eu-repo/grantAgreement/AEI//EUR2020-112157info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2021-2023/CEX2019-000918-Minfo:eu-repo/grantAgreement/EC/H2020/834148https://doi.org/10.1093/mnras/stae1961Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/3715342026-05-22T06:33:51Z
dc.title.none.fl_str_mv Capture of field stars by dark substructures
title Capture of field stars by dark substructures
spellingShingle Capture of field stars by dark substructures
Peñarrubia, Jorge
Galaxy: kinematics and dynamics
Galaxies: evolution
Cosmology: dark matter
title_short Capture of field stars by dark substructures
title_full Capture of field stars by dark substructures
title_fullStr Capture of field stars by dark substructures
title_full_unstemmed Capture of field stars by dark substructures
title_sort Capture of field stars by dark substructures
dc.creator.none.fl_str_mv Peñarrubia, Jorge
Errani, Raphaël
Walker, Alistair R.
Gieles, Mark
Boekholt, Tjarda C. N.
author Peñarrubia, Jorge
author_facet Peñarrubia, Jorge
Errani, Raphaël
Walker, Alistair R.
Gieles, Mark
Boekholt, Tjarda C. N.
author_role author
author2 Errani, Raphaël
Walker, Alistair R.
Gieles, Mark
Boekholt, Tjarda C. N.
author2_role author
author
author
author
dc.contributor.none.fl_str_mv National Science Foundation (US)
Agencia Estatal de Investigación (España)
Ministerio de Ciencia, Innovación y Universidades (España)
Generalitat de Catalunya
European Commission
European Research Council
NASA
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Galaxy: kinematics and dynamics
Galaxies: evolution
Cosmology: dark matter
topic Galaxy: kinematics and dynamics
Galaxies: evolution
Cosmology: dark matter
description We use analytical and N-body methods to study the capture of field stars by gravitating substructures moving across a galactic environment. The majority of stars captured by a substructure mo v e on temporarily bound orbits that are lost to galactic tides after a few orbital revolutions. In numerical experiments where a substructure model is immersed into a sea of field particles on a circular orbit, we find a population of particles that remain bound to the substructure potential for indefinitely long times. This population is absent from substructure models, initially placed outside the galaxy on an eccentric orbit. We show that gravitational capture is most efficient in dwarf spheroidal galaxies (dSphs) on account of their low velocity dispersions and high stellar phase-space densities. In these galaxies, ‘dark’ sub-subhaloes, which do not experience in situ star formation, may capture f ield stars and become visible as stellar o v erdensities with unusual properties: (i) they would have a large size for their luminosity, (ii) contain stellar populations indistinguishable from the host galaxy, and (iii) exhibit dark matter (DM)-dominated mass-to- light ratios. We discuss the nature of several ‘anomalous’ stellar systems reported as star clusters in the Fornax and Eridanus II dSphs that exhibit some of these characteristics. DM sub-subhaloes with a mass function d N/ d M • ∼ M −α • are expected to generate stellar systems with a luminosity function, d N/ d M ∼ M −β , where β = (2 α + 1) / 3 = 1 . 6 for α = 1 . 9. Detecting and characterizing these objects in dSphs would provide unprecedented constraints on the particle mass and cross-section of a large range of DM particle candidates.
publishDate 2024
dc.date.none.fl_str_mv 2024
2024
2024
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Publisher's version
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/371534
url http://hdl.handle.net/10261/371534
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
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info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2021-2023/PID2021-125485NB-C22
info:eu-repo/grantAgreement/AEI//EUR2020-112157
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2021-2023/CEX2019-000918-M
info:eu-repo/grantAgreement/EC/H2020/834148
https://doi.org/10.1093/mnras/stae1961
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
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dc.publisher.none.fl_str_mv Oxford University Press
publisher.none.fl_str_mv Oxford University Press
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
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