The age-metallicity relationship of the large magellanic cloud field star population from wide-field washington photometry

We analyze age and metallicity estimates for an unprecedented database of some 5.5 million stars distributed throughout the Large Magellanic Cloud (LMC) main body, obtained from CCD Washington CT1 photometry, reported on in Piatti etal. We produce a comprehensive field star age-metallicity relations...

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Publicado: 2013
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00046256_v145_n1_p_Piatti
http://hdl.handle.net/20.500.12110/paper_00046256_v145_n1_p_Piatti
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling paper:paper_00046256_v145_n1_p_Piatti2023-06-08T14:27:15Z The age-metallicity relationship of the large magellanic cloud field star population from wide-field washington photometry We analyze age and metallicity estimates for an unprecedented database of some 5.5 million stars distributed throughout the Large Magellanic Cloud (LMC) main body, obtained from CCD Washington CT1 photometry, reported on in Piatti etal. We produce a comprehensive field star age-metallicity relationship (AMR) from the earliest epoch until ∼1Gyr ago. This AMR reveals that the LMC has not evolved chemically as either a closed-box or bursting system, exclusively, but as a combination of both scenarios that have varied in relative strength over the lifetime of the galaxy, although the bursting model falls closer to the data in general. Furthermore, while old and metal-poor field stars have been preferentially formed in the outer disk, younger and more metal-rich stars have mostly been formed in the inner disk, confirming an outside-in formation. We provide evidence for the formation of stars between 5 and 12Gyr, during the cluster age gap, although chemical enrichment during this period was minimal. We find no significant metallicity gradient in the LMC. We also find that the range in the metallicity of an LMC field has varied during the lifetime of the LMC. In particular, we find only a small range of the metal abundance in the outer disk fields, whereas an average range of Δ[Fe/H] = +0.3 ± 0.1 dex appears in the inner disk fields. Finally, the cluster and field AMRs show a satisfactory match only for the last 3Gyr, while for the oldest ages (>11Gyr), the cluster AMR is a remarkable lower envelope to the field AMR. Such a difference may be due to the very rapid early chemical evolution and lack of observed field stars in this regime, whereas the globular clusters are easily studied. This large difference is not easy to explain as coming from stripped ancient Small Magellanic Cloud (SMC) clusters, although the field SMC AMR is on average ∼0.4 dex more metal-poor at all ages than that of the LMC but otherwise very similar. © 2013. The American Astronomical Society. All rights reserved. 2013 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00046256_v145_n1_p_Piatti http://hdl.handle.net/20.500.12110/paper_00046256_v145_n1_p_Piatti
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description We analyze age and metallicity estimates for an unprecedented database of some 5.5 million stars distributed throughout the Large Magellanic Cloud (LMC) main body, obtained from CCD Washington CT1 photometry, reported on in Piatti etal. We produce a comprehensive field star age-metallicity relationship (AMR) from the earliest epoch until ∼1Gyr ago. This AMR reveals that the LMC has not evolved chemically as either a closed-box or bursting system, exclusively, but as a combination of both scenarios that have varied in relative strength over the lifetime of the galaxy, although the bursting model falls closer to the data in general. Furthermore, while old and metal-poor field stars have been preferentially formed in the outer disk, younger and more metal-rich stars have mostly been formed in the inner disk, confirming an outside-in formation. We provide evidence for the formation of stars between 5 and 12Gyr, during the cluster age gap, although chemical enrichment during this period was minimal. We find no significant metallicity gradient in the LMC. We also find that the range in the metallicity of an LMC field has varied during the lifetime of the LMC. In particular, we find only a small range of the metal abundance in the outer disk fields, whereas an average range of Δ[Fe/H] = +0.3 ± 0.1 dex appears in the inner disk fields. Finally, the cluster and field AMRs show a satisfactory match only for the last 3Gyr, while for the oldest ages (>11Gyr), the cluster AMR is a remarkable lower envelope to the field AMR. Such a difference may be due to the very rapid early chemical evolution and lack of observed field stars in this regime, whereas the globular clusters are easily studied. This large difference is not easy to explain as coming from stripped ancient Small Magellanic Cloud (SMC) clusters, although the field SMC AMR is on average ∼0.4 dex more metal-poor at all ages than that of the LMC but otherwise very similar. © 2013. The American Astronomical Society. All rights reserved.
title The age-metallicity relationship of the large magellanic cloud field star population from wide-field washington photometry
spellingShingle The age-metallicity relationship of the large magellanic cloud field star population from wide-field washington photometry
title_short The age-metallicity relationship of the large magellanic cloud field star population from wide-field washington photometry
title_full The age-metallicity relationship of the large magellanic cloud field star population from wide-field washington photometry
title_fullStr The age-metallicity relationship of the large magellanic cloud field star population from wide-field washington photometry
title_full_unstemmed The age-metallicity relationship of the large magellanic cloud field star population from wide-field washington photometry
title_sort age-metallicity relationship of the large magellanic cloud field star population from wide-field washington photometry
publishDate 2013
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00046256_v145_n1_p_Piatti
http://hdl.handle.net/20.500.12110/paper_00046256_v145_n1_p_Piatti
_version_ 1768543635802947584

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