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The Not so Simple S...
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Calamida, AnnalisaSpace Telescope Science Institute
(author)
The Not so Simple Stellar System ω Cen. II. Evidence in Support of a Merging Scenario
- Article/chapterEnglish2020
Publisher, publication year, extent ...
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2020-03-17
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American Astronomical Society,2020
Numbers
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LIBRIS-ID:oai:lup.lub.lu.se:cdd058d6-f88f-452b-b9d1-e4a84bc1f680
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https://lup.lub.lu.se/record/cdd058d6-f88f-452b-b9d1-e4a84bc1f680URI
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https://doi.org/10.3847/1538-4357/ab77c0DOI
Supplementary language notes
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Language:English
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Summary in:English
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Subject category:art swepub-publicationtype
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Subject category:ref swepub-contenttype
Notes
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We present multiband photometry covering ∼5° × 5° across ω Cen collected with the Dark Energy Camera on the 4 m Blanco telescope, combined with Hubble Space Telescope and Wide Field Imager data for the central regions. The unprecedented photometric accuracy and field coverage allows us to confirm the different spatial distribution of blue and red main-sequence stars, and of red giant branch (RGB) stars with different metallicities. The ratio of the number of blue to red main-sequence stars shows that the blue main-sequence stellar subpopulation has a more extended spatial distribution compared to the red main-sequence one, with the frequency of blue main-sequence stars increasing at a distance of ∼20′ from ω Cen's center. Similarly, the more metal-rich RGB stars show a more extended spatial distribution compared to the more metal-poor ones in the outskirts of the cluster. Moreover, the centers of the distributions of metal-rich and metal-poor RGB stars are shifted in different directions with respect to the geometrical center of ω Cen. We constructed stellar density profiles for the blue and red main-sequence stars; they show that the blue main-sequence stellar subpopulation has a more extended spatial distribution compared to the red main-sequence one in the outskirts of ω Cen, confirming the results based on the number ratio. We also computed the ellipticity profile of ω Cen, which has a maximum value of 0.16 at a distance of ∼8′ from the center, and a minimum of 0.05 at ∼30′; the average ellipticity is ∼0.10. The circumstantial evidence presented in this work suggests a merging scenario for the formation of the peculiar stellar system ω Cen.
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Zocchi, AliceEuropean Space Research and Technology Centre (ESA/ESTEC)
(author)
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Bono, GiuseppeINAF-Osservatorio Astronomico di Roma,University of Rome Tor Vergata
(author)
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Ferraro, IvanINAF-Osservatorio Astronomico di Roma
(author)
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Mastrobuono-Battisti, AlessandraLund University,Lunds universitet,Astronomi - Genomgår omorganisation,Institutionen för astronomi och teoretisk fysik - Genomgår omorganisation,Naturvetenskapliga fakulteten,Lund Observatory - Undergoing reorganization,Department of Astronomy and Theoretical Physics - Undergoing reorganization,Faculty of Science,Max Planck Institute for Astronomy(Swepub:lu)al2550ma
(author)
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Saha, AbhijitNational Optical Astronomy Observatory
(author)
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Iannicola, GiacintoINAF-Osservatorio Astronomico di Roma
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Rest, ArminSpace Telescope Science Institute,Johns Hopkins University
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Strampelli, GiovanniUniversity of La Laguna (ULL),Johns Hopkins University
(author)
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Zenteno, AlfredoCerro Tololo Inter-American Observatory, NOAO
(author)
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Space Telescope Science InstituteEuropean Space Research and Technology Centre (ESA/ESTEC)
(creator_code:org_t)
Related titles
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In:Astrophysical Journal: American Astronomical Society891:20004-637X1538-4357
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