Near-infrared photometry of globular clusters towards the Galactic bulge : observations and photometric metallicity indicators

Detalhes bibliográficos
Autor(a) principal: Cohen, Roger
Data de Publicação: 2017
Outros Autores: Moni Bidin, Christian, Mauro, Francesco, Bonatto, Charles Jose, Geisler, Doug
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Institucional da UFRGS
Texto Completo: http://hdl.handle.net/10183/165000
Resumo: We present wide-field JHKS photometry of 16 Galactic globular clusters located towards the Galactic bulge, calibrated on the Two Micron All-Sky Survey photometric system. Differential reddening corrections and statistical field star decontamination are employed for all of these clusters before fitting fiducial sequences to the cluster red giant branches (RGBs). Observed values and uncertainties are reported for several photometric features, including the magnitude of the RGB bump, tip, the horizontal branch (HB) and the slope of the upper RGB. The latest spectroscopically determined chemical abundances are used to build distance- and reddening-independent relations between observed photometric features and cluster metallicity, optimizing the sample size and metallicity baseline of these relations by supplementing our sample with results from the literature.We find that the magnitude difference between the HB and the RGB bump can be used to predict metallicities, in terms of both iron abundance [Fe/H] and global metallicity [M/H], with a precision of better than 0.1 dex in all three near-IR bandpasses for relatively metal-rich ([M/H] −1) clusters. Meanwhile, both the slope of the upper RGB and the magnitude difference between the RGB tip and bump are useful metallicity indicators over the entire sampled metallicity range (−2 [M/H] 0) with a precision of 0.2 dex or better, despite model predictions that the RGB slope may become unreliable at high (near-solar) metallicities. Our results agree with previous calibrations in light of the relevant uncertainties, and we discuss implications for clusters with controversial metallicities as well as directions for further investigation.
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spelling Cohen, RogerMoni Bidin, ChristianMauro, FrancescoBonatto, Charles JoseGeisler, Doug2017-08-09T02:37:06Z20170035-8711http://hdl.handle.net/10183/165000001021497We present wide-field JHKS photometry of 16 Galactic globular clusters located towards the Galactic bulge, calibrated on the Two Micron All-Sky Survey photometric system. Differential reddening corrections and statistical field star decontamination are employed for all of these clusters before fitting fiducial sequences to the cluster red giant branches (RGBs). Observed values and uncertainties are reported for several photometric features, including the magnitude of the RGB bump, tip, the horizontal branch (HB) and the slope of the upper RGB. The latest spectroscopically determined chemical abundances are used to build distance- and reddening-independent relations between observed photometric features and cluster metallicity, optimizing the sample size and metallicity baseline of these relations by supplementing our sample with results from the literature.We find that the magnitude difference between the HB and the RGB bump can be used to predict metallicities, in terms of both iron abundance [Fe/H] and global metallicity [M/H], with a precision of better than 0.1 dex in all three near-IR bandpasses for relatively metal-rich ([M/H] −1) clusters. Meanwhile, both the slope of the upper RGB and the magnitude difference between the RGB tip and bump are useful metallicity indicators over the entire sampled metallicity range (−2 [M/H] 0) with a precision of 0.2 dex or better, despite model predictions that the RGB slope may become unreliable at high (near-solar) metallicities. Our results agree with previous calibrations in light of the relevant uncertainties, and we discuss implications for clusters with controversial metallicities as well as directions for further investigation.application/pdfengMonthly notices of the Royal Astronomical Society. Oxford. Vol. 464, no. 2 (Jan. 2017), p. 1874-1902Aglomerados globularesBojos de galaxiasFotometria astronômicaMetalicidadeGlobular clustersGeneral – infraredStarsNear-infrared photometry of globular clusters towards the Galactic bulge : observations and photometric metallicity indicatorsEstrangeiroinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSORIGINAL001021497.pdf001021497.pdfTexto completo (inglês)application/pdf8717166http://www.lume.ufrgs.br/bitstream/10183/165000/1/001021497.pdff98c923f594a480999a450d1c9ceb1e6MD51TEXT001021497.pdf.txt001021497.pdf.txtExtracted Texttext/plain142964http://www.lume.ufrgs.br/bitstream/10183/165000/2/001021497.pdf.txt93816a9a3a51cace91c3c18365168e97MD52THUMBNAIL001021497.pdf.jpg001021497.pdf.jpgGenerated Thumbnailimage/jpeg2089http://www.lume.ufrgs.br/bitstream/10183/165000/3/001021497.pdf.jpgbefe6879ccc14f69c4648c4755155161MD5310183/1650002023-07-15 03:28:50.385484oai:www.lume.ufrgs.br:10183/165000Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2023-07-15T06:28:50Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false
dc.title.pt_BR.fl_str_mv Near-infrared photometry of globular clusters towards the Galactic bulge : observations and photometric metallicity indicators
title Near-infrared photometry of globular clusters towards the Galactic bulge : observations and photometric metallicity indicators
spellingShingle Near-infrared photometry of globular clusters towards the Galactic bulge : observations and photometric metallicity indicators
Cohen, Roger
Aglomerados globulares
Bojos de galaxias
Fotometria astronômica
Metalicidade
Globular clusters
General – infrared
Stars
title_short Near-infrared photometry of globular clusters towards the Galactic bulge : observations and photometric metallicity indicators
title_full Near-infrared photometry of globular clusters towards the Galactic bulge : observations and photometric metallicity indicators
title_fullStr Near-infrared photometry of globular clusters towards the Galactic bulge : observations and photometric metallicity indicators
title_full_unstemmed Near-infrared photometry of globular clusters towards the Galactic bulge : observations and photometric metallicity indicators
title_sort Near-infrared photometry of globular clusters towards the Galactic bulge : observations and photometric metallicity indicators
author Cohen, Roger
author_facet Cohen, Roger
Moni Bidin, Christian
Mauro, Francesco
Bonatto, Charles Jose
Geisler, Doug
author_role author
author2 Moni Bidin, Christian
Mauro, Francesco
Bonatto, Charles Jose
Geisler, Doug
author2_role author
author
author
author
dc.contributor.author.fl_str_mv Cohen, Roger
Moni Bidin, Christian
Mauro, Francesco
Bonatto, Charles Jose
Geisler, Doug
dc.subject.por.fl_str_mv Aglomerados globulares
Bojos de galaxias
Fotometria astronômica
Metalicidade
topic Aglomerados globulares
Bojos de galaxias
Fotometria astronômica
Metalicidade
Globular clusters
General – infrared
Stars
dc.subject.eng.fl_str_mv Globular clusters
General – infrared
Stars
description We present wide-field JHKS photometry of 16 Galactic globular clusters located towards the Galactic bulge, calibrated on the Two Micron All-Sky Survey photometric system. Differential reddening corrections and statistical field star decontamination are employed for all of these clusters before fitting fiducial sequences to the cluster red giant branches (RGBs). Observed values and uncertainties are reported for several photometric features, including the magnitude of the RGB bump, tip, the horizontal branch (HB) and the slope of the upper RGB. The latest spectroscopically determined chemical abundances are used to build distance- and reddening-independent relations between observed photometric features and cluster metallicity, optimizing the sample size and metallicity baseline of these relations by supplementing our sample with results from the literature.We find that the magnitude difference between the HB and the RGB bump can be used to predict metallicities, in terms of both iron abundance [Fe/H] and global metallicity [M/H], with a precision of better than 0.1 dex in all three near-IR bandpasses for relatively metal-rich ([M/H] −1) clusters. Meanwhile, both the slope of the upper RGB and the magnitude difference between the RGB tip and bump are useful metallicity indicators over the entire sampled metallicity range (−2 [M/H] 0) with a precision of 0.2 dex or better, despite model predictions that the RGB slope may become unreliable at high (near-solar) metallicities. Our results agree with previous calibrations in light of the relevant uncertainties, and we discuss implications for clusters with controversial metallicities as well as directions for further investigation.
publishDate 2017
dc.date.accessioned.fl_str_mv 2017-08-09T02:37:06Z
dc.date.issued.fl_str_mv 2017
dc.type.driver.fl_str_mv Estrangeiro
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dc.language.iso.fl_str_mv eng
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dc.relation.ispartof.pt_BR.fl_str_mv Monthly notices of the Royal Astronomical Society. Oxford. Vol. 464, no. 2 (Jan. 2017), p. 1874-1902
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