Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch Stars

Autores
Santucci, Rafael M.; Beers, Timothy C.; Placco, Vinicius M.; Carollo, Daniela; Rossi, Silvia; Lee, Young Sun; Denissenkov, Pavel; Tumlinson, Jason; Tissera, Patricia Beatriz
Año de publicación
2015
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
In a pioneering effort, Preston et al. reported that the colors of bluehorizontal-branch (BHB) stars in the halo of the Galaxy shift withdistance, from regions near the Galactic center to about 12 kpc away,and interpreted this as a correlated variation in the ages of halostars, from older to younger, spanning a range of a few Gyrs. We haveapplied this approach to a sample of some 4700 spectroscopicallyconfirmed BHB stars selected from the Sloan Digital Sky Survey toproduce the first ?chronographic map? of the halo of theGalaxy. We demonstrate that the mean de-reddened g ‑ r color, <{(g-r)}0> , increases outward in the Galaxy from‑0.22 to ‑0.08 (over a color window spanning [‑0.3:0.0]) from regions close to the Galactic center to ∼40 kpc,independent of the metallicity of the stars. Models of the expectedshift in the color of the field BHB stars based on modern stellarevolutionary codes confirm that this color gradient can be associatedwith an age difference of roughly 2?2.5 Gyr, with the oldest starsconcentrated in the central ∼15 kpc of the Galaxy. Within thiscentral region, the age difference spans a mean color range of about0.05 mag (∼0.8 Gyr). Furthermore, we show that chronographic mapscan be used to identify individual substructures, such as theSagittarius Stream, and overdensities in the direction of Virgo andMonoceros, based on the observed contrast in their mean BHB colors withrespect to the foreground/background field population.
Fil: Santucci, Rafael M.. Universidade Do Sao Paulo. Instituto Astronomia, Geofisica E Ciencias Atmosfericas; Brasil
Fil: Beers, Timothy C.. University Of Notre Dame-indiana; Estados Unidos
Fil: Placco, Vinicius M.. University Of Notre Dame-indiana; Estados Unidos
Fil: Carollo, Daniela. University Of Notre Dame-indiana; Estados Unidos
Fil: Rossi, Silvia. Universidade Do Sao Paulo. Instituto Astronomia, Geofisica E Ciencias Atmosfericas; Brasil
Fil: Lee, Young Sun. Chungnam National University; Corea del Sur
Fil: Denissenkov, Pavel. University Of Victoria; Canadá
Fil: Tumlinson, Jason. Space Telescope Science Institute; Estados Unidos
Fil: Tissera, Patricia Beatriz. Universidad Andres Bello; Chile. 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
Galaxy: halo
Methods: observational
Methods: statistical
Stars: horizontal-branch
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:11336/17847
Acceder
id CONICETDig_ad7011d14de5e53a817d488abd9de998
oai_identifier_str oai:ri.conicet.gov.ar:11336/17847
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch StarsSantucci, Rafael M.Beers, Timothy C.Placco, Vinicius M.Carollo, DanielaRossi, SilviaLee, Young SunDenissenkov, PavelTumlinson, JasonTissera, Patricia BeatrizGalaxy: haloMethods: observationalMethods: statisticalStars: horizontal-branchhttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1In a pioneering effort, Preston et al. reported that the colors of bluehorizontal-branch (BHB) stars in the halo of the Galaxy shift withdistance, from regions near the Galactic center to about 12 kpc away,and interpreted this as a correlated variation in the ages of halostars, from older to younger, spanning a range of a few Gyrs. We haveapplied this approach to a sample of some 4700 spectroscopicallyconfirmed BHB stars selected from the Sloan Digital Sky Survey toproduce the first ?chronographic map? of the halo of theGalaxy. We demonstrate that the mean de-reddened g ‑ r color, <{(g-r)}<sub>0</sub>> , increases outward in the Galaxy from‑0.22 to ‑0.08 (over a color window spanning [‑0.3:0.0]) from regions close to the Galactic center to ∼40 kpc,independent of the metallicity of the stars. Models of the expectedshift in the color of the field BHB stars based on modern stellarevolutionary codes confirm that this color gradient can be associatedwith an age difference of roughly 2?2.5 Gyr, with the oldest starsconcentrated in the central ∼15 kpc of the Galaxy. Within thiscentral region, the age difference spans a mean color range of about0.05 mag (∼0.8 Gyr). Furthermore, we show that chronographic mapscan be used to identify individual substructures, such as theSagittarius Stream, and overdensities in the direction of Virgo andMonoceros, based on the observed contrast in their mean BHB colors withrespect to the foreground/background field population.Fil: Santucci, Rafael M.. Universidade Do Sao Paulo. Instituto Astronomia, Geofisica E Ciencias Atmosfericas; BrasilFil: Beers, Timothy C.. University Of Notre Dame-indiana; Estados UnidosFil: Placco, Vinicius M.. University Of Notre Dame-indiana; Estados UnidosFil: Carollo, Daniela. University Of Notre Dame-indiana; Estados UnidosFil: Rossi, Silvia. Universidade Do Sao Paulo. Instituto Astronomia, Geofisica E Ciencias Atmosfericas; BrasilFil: Lee, Young Sun. Chungnam National University; Corea del SurFil: Denissenkov, Pavel. University Of Victoria; CanadáFil: Tumlinson, Jason. Space Telescope Science Institute; Estados UnidosFil: Tissera, Patricia Beatriz. Universidad Andres Bello; Chile. 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; ArgentinaIop Publishing2015-11-01info: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/11336/17847Santucci, Rafael M.; Beers, Timothy C.; Placco, Vinicius M.; Carollo, Daniela; Rossi, Silvia; et al.; Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch Stars; Iop Publishing; Astrophysical Journal; 813; 1-11-2015; 1-6; L160004-637Xenginfo:eu-repo/semantics/altIdentifier/doi/10.1088/2041-8205/813/1/L16info:eu-repo/semantics/altIdentifier/url/https://arxiv.org/abs/1510.08147info:eu-repo/semantics/altIdentifier/url/http://iopscience.iop.org/article/10.1088/2041-8205/813/1/L16/metainfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T10:00:12Zoai:ri.conicet.gov.ar:11336/17847instacron: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 10:00:12.608CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch Stars
title Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch Stars
spellingShingle Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch Stars
Santucci, Rafael M.
Galaxy: halo
Methods: observational
Methods: statistical
Stars: horizontal-branch
title_short Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch Stars
title_full Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch Stars
title_fullStr Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch Stars
title_full_unstemmed Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch Stars
title_sort Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch Stars
dc.creator.none.fl_str_mv Santucci, Rafael M.
Beers, Timothy C.
Placco, Vinicius M.
Carollo, Daniela
Rossi, Silvia
Lee, Young Sun
Denissenkov, Pavel
Tumlinson, Jason
Tissera, Patricia Beatriz
author Santucci, Rafael M.
author_facet Santucci, Rafael M.
Beers, Timothy C.
Placco, Vinicius M.
Carollo, Daniela
Rossi, Silvia
Lee, Young Sun
Denissenkov, Pavel
Tumlinson, Jason
Tissera, Patricia Beatriz
author_role author
author2 Beers, Timothy C.
Placco, Vinicius M.
Carollo, Daniela
Rossi, Silvia
Lee, Young Sun
Denissenkov, Pavel
Tumlinson, Jason
Tissera, Patricia Beatriz
author2_role author
author
author
author
author
author
author
author
dc.subject.none.fl_str_mv Galaxy: halo
Methods: observational
Methods: statistical
Stars: horizontal-branch
topic Galaxy: halo
Methods: observational
Methods: statistical
Stars: horizontal-branch
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv In a pioneering effort, Preston et al. reported that the colors of bluehorizontal-branch (BHB) stars in the halo of the Galaxy shift withdistance, from regions near the Galactic center to about 12 kpc away,and interpreted this as a correlated variation in the ages of halostars, from older to younger, spanning a range of a few Gyrs. We haveapplied this approach to a sample of some 4700 spectroscopicallyconfirmed BHB stars selected from the Sloan Digital Sky Survey toproduce the first ?chronographic map? of the halo of theGalaxy. We demonstrate that the mean de-reddened g ‑ r color, <{(g-r)}<sub>0</sub>> , increases outward in the Galaxy from‑0.22 to ‑0.08 (over a color window spanning [‑0.3:0.0]) from regions close to the Galactic center to ∼40 kpc,independent of the metallicity of the stars. Models of the expectedshift in the color of the field BHB stars based on modern stellarevolutionary codes confirm that this color gradient can be associatedwith an age difference of roughly 2?2.5 Gyr, with the oldest starsconcentrated in the central ∼15 kpc of the Galaxy. Within thiscentral region, the age difference spans a mean color range of about0.05 mag (∼0.8 Gyr). Furthermore, we show that chronographic mapscan be used to identify individual substructures, such as theSagittarius Stream, and overdensities in the direction of Virgo andMonoceros, based on the observed contrast in their mean BHB colors withrespect to the foreground/background field population.
Fil: Santucci, Rafael M.. Universidade Do Sao Paulo. Instituto Astronomia, Geofisica E Ciencias Atmosfericas; Brasil
Fil: Beers, Timothy C.. University Of Notre Dame-indiana; Estados Unidos
Fil: Placco, Vinicius M.. University Of Notre Dame-indiana; Estados Unidos
Fil: Carollo, Daniela. University Of Notre Dame-indiana; Estados Unidos
Fil: Rossi, Silvia. Universidade Do Sao Paulo. Instituto Astronomia, Geofisica E Ciencias Atmosfericas; Brasil
Fil: Lee, Young Sun. Chungnam National University; Corea del Sur
Fil: Denissenkov, Pavel. University Of Victoria; Canadá
Fil: Tumlinson, Jason. Space Telescope Science Institute; Estados Unidos
Fil: Tissera, Patricia Beatriz. Universidad Andres Bello; Chile. 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 In a pioneering effort, Preston et al. reported that the colors of bluehorizontal-branch (BHB) stars in the halo of the Galaxy shift withdistance, from regions near the Galactic center to about 12 kpc away,and interpreted this as a correlated variation in the ages of halostars, from older to younger, spanning a range of a few Gyrs. We haveapplied this approach to a sample of some 4700 spectroscopicallyconfirmed BHB stars selected from the Sloan Digital Sky Survey toproduce the first ?chronographic map? of the halo of theGalaxy. We demonstrate that the mean de-reddened g ‑ r color, <{(g-r)}<sub>0</sub>> , increases outward in the Galaxy from‑0.22 to ‑0.08 (over a color window spanning [‑0.3:0.0]) from regions close to the Galactic center to ∼40 kpc,independent of the metallicity of the stars. Models of the expectedshift in the color of the field BHB stars based on modern stellarevolutionary codes confirm that this color gradient can be associatedwith an age difference of roughly 2?2.5 Gyr, with the oldest starsconcentrated in the central ∼15 kpc of the Galaxy. Within thiscentral region, the age difference spans a mean color range of about0.05 mag (∼0.8 Gyr). Furthermore, we show that chronographic mapscan be used to identify individual substructures, such as theSagittarius Stream, and overdensities in the direction of Virgo andMonoceros, based on the observed contrast in their mean BHB colors withrespect to the foreground/background field population.
publishDate 2015
dc.date.none.fl_str_mv 2015-11-01
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/11336/17847
Santucci, Rafael M.; Beers, Timothy C.; Placco, Vinicius M.; Carollo, Daniela; Rossi, Silvia; et al.; Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch Stars; Iop Publishing; Astrophysical Journal; 813; 1-11-2015; 1-6; L16
0004-637X
url http://hdl.handle.net/11336/17847
identifier_str_mv Santucci, Rafael M.; Beers, Timothy C.; Placco, Vinicius M.; Carollo, Daniela; Rossi, Silvia; et al.; Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch Stars; Iop Publishing; Astrophysical Journal; 813; 1-11-2015; 1-6; L16
0004-637X
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1088/2041-8205/813/1/L16
info:eu-repo/semantics/altIdentifier/url/https://arxiv.org/abs/1510.08147
info:eu-repo/semantics/altIdentifier/url/http://iopscience.iop.org/article/10.1088/2041-8205/813/1/L16/meta
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 Iop Publishing
publisher.none.fl_str_mv Iop Publishing
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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