Utilizza questo identificativo per citare o creare un link a questo documento:
http://hdl.handle.net/20.500.12386/29254
Campo DC | Valore | Lingua |
---|---|---|
dc.contributor.author | MASSARI, DAVIDE | en_US |
dc.contributor.author | Breddels, M. A. | en_US |
dc.contributor.author | Helmi, A. | en_US |
dc.contributor.author | Posti, L. | en_US |
dc.contributor.author | Brown, A. G. A. | en_US |
dc.contributor.author | Tolstoy, E. | en_US |
dc.date.accessioned | 2020-12-28T17:23:01Z | - |
dc.date.available | 2020-12-28T17:23:01Z | - |
dc.date.issued | 2018 | en_US |
dc.identifier.issn | 2397-3366 | en_US |
dc.identifier.uri | http://hdl.handle.net/20.500.12386/29254 | - |
dc.description.abstract | The three-dimensional motions of stars in small galaxies beyond our own are minute, yet they are crucial for understanding the nature of gravity and dark matter<SUP>1,2</SUP>. Even for the dwarf galaxy Sculptor—one of the best-studied systems, which is inferred to be strongly dark matter dominated<SUP>3,4</SUP>—there are conflicting reports<SUP>5-7</SUP> on its mean motion around the Milky Way, and the three-dimensional internal motions of its stars have never been measured. Here, we present precise proper motions of Sculptor's stars based on data from the Gaia mission<SUP>8</SUP> and Hubble Space Telescope. Our measurements show that Sculptor moves around the Milky Way on a high-inclination elongated orbit that takes it much further out than previously thought. For Sculptor's internal velocity dispersions, we find σ<SUB>R</SUB> = 11.5 ± 4.3 km s<SUP>-1</SUP> and σ<SUB>T</SUB> = 8.5 ± 3.2 km s<SUP>-1</SUP> along the projected radial and tangential directions. Thus, the stars in our sample move preferentially on radial orbits as quantified by the anisotropy parameter, which we find to be β <mml:mstyle fontfamily="Whitney Semibold"> 0.8 6<SUB>-0.83</SUB><SUP>+0.12</SUP></mml:mstyle> at a location beyond the core radius. Taken at face value, this high radial anisotropy requires abandoning conventional models<SUP>9</SUP> for Sculptor's mass distribution. Our sample is dominated by metal-rich stars and for these we find <mml:mstyle fontfamily="Whitney semibold">β<SUP>M R</SUP> 0.9 5<SUB>-0.27</SUB><SUP>+0.04</SUP></mml:mstyle>—a value consistent with multi-component spherical models where Sculptor is embedded in a cuspy dark halo<SUP>10</SUP>, as might be expected for cold dark matter. | en_US |
dc.language.iso | eng | en_US |
dc.title | Three-dimensional motions in the Sculptor dwarf galaxy as a glimpse of a new era | en_US |
dc.type | Article | - |
dc.identifier.doi | 10.1038/s41550-017-0322-y | en_US |
dc.identifier.scopus | 2-s2.0-85041287126 | en_US |
dc.identifier.isi | 000423482100017 | en_US |
dc.identifier.url | https://www.nature.com/articles/s41550-017-0322-y | en_US |
dc.relation.medium | ELETTRONICO | en_US |
dc.relation.volume | 2 | en_US |
dc.relation.firstpage | 156 | en_US |
dc.type.referee | REF_1 | en_US |
dc.description.international | sì | en_US |
dc.contributor.country | ITA | en_US |
dc.relation.scientificsector | FIS/05 - ASTRONOMIA E ASTROFISICA | en_US |
dc.relation.journal | NATURE ASTRONOMY | en_US |
dc.type.miur | 262 Articolo in rivista | - |
dc.identifier.adsbibcode | 2018NatAs...2..156M | en_US |
dc.description.apc | no | en_US |
dc.description.oa | 1 – prodotto con file in versione Open Access (allegare il file al passo 5-Carica) | en_US |
item.openairecristype | http://purl.org/coar/resource_type/c_18cf | - |
item.openairetype | Article | - |
item.languageiso639-1 | en | - |
item.cerifentitytype | Publications | - |
item.grantfulltext | open | - |
item.fulltext | With Fulltext | - |
crisitem.author.dept | OAS Bologna | - |
crisitem.author.orcid | 0000-0001-8892-4301 | - |
crisitem.journal.journalissn | 2397-3366 | - |
crisitem.journal.ance | E240167 | - |
È visualizzato nelle collezioni: | 1.01 Articoli in rivista |
File in questo documento:
File | Descrizione | Dimensioni | Formato | |
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1711.08945.pdf | preprint | 1.48 MB | Adobe PDF | Visualizza/apri |
Nat. Astr. main 2_156.pdf | [Administrators only] | 4.98 MB | Adobe PDF |
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