Utilizza questo identificativo per citare o creare un link a questo documento:
http://hdl.handle.net/20.500.12386/31132
Campo DC | Valore | Lingua |
---|---|---|
dc.contributor.author | MASSARI, DAVIDE | en_US |
dc.contributor.author | Amina Helmi | en_US |
dc.contributor.author | Mucciarelli, Alessio | en_US |
dc.contributor.author | Laura V. Sales | en_US |
dc.contributor.author | SPINA, LORENZO | en_US |
dc.contributor.author | Eline Tolstoy | en_US |
dc.date.accessioned | 2021-11-24T13:46:26Z | - |
dc.date.available | 2021-11-24T13:46:26Z | - |
dc.date.issued | 2020 | en_US |
dc.identifier.issn | 0004-6361 | en_US |
dc.identifier.uri | http://hdl.handle.net/20.500.12386/31132 | - |
dc.description.abstract | Aims. We present the first three-dimensional internal motions for individual stars in the Draco dwarf spheroidal galaxy. Methods. By combining first-epoch $Hubble$ $Space$ $Telescope$ observations and second-epoch $Gaia$ Data Release 2 positions, we measured the proper motions of $149$ sources in the direction of Draco. We determined the line-of-sight velocities for a sub-sample of $81$ red giant branch stars using medium resolution spectra acquired with the DEIMOS spectrograph at the Keck II telescope. Altogether, this resulted in a final sample of $45$ Draco members with high-precision and accurate 3D motions, which we present as a table in this paper. Results. Based on this high-quality dataset, we determined the velocity dispersions at a projected distance of $\sim120$ pc from the centre of Draco to be $\sigma_{R} =11.0^{+2.1}_{-1.5}$ km/s, $\sigma_{T}=9.9^{+2.3}_{-3.1}$ km/s and $\sigma_{LOS}=9.0^{+1.1}_{-1.1}$ km/s in the projected radial, tangential, and line-of-sight directions. This results in a velocity anisotropy $\beta=0.25^{+0.47}_{-1.38}$ at $r \gtrsim120$ pc. Tighter constraints may be obtained using the spherical Jeans equations and assuming constant anisotropy and Navarro-Frenk-White (NFW) mass profiles, also based on the assumption that the 3D velocity dispersion should be lower than $\approx 1/3$ of the escape velocity of the system. In this case, we constrain the maximum circular velocity $V_{max}$ of Draco to be in the range of $10.2-17.0$ km/s. The corresponding mass range is in good agreement with previous estimates based on line-of-sight velocities only. Conclusions. Our Jeans modelling supports the case for a cuspy dark matter profile in this galaxy. Firmer conclusions may be drawn by applying more sophisticated models to this dataset and with new datasets from upcoming $Gaia$ releases. | en_US |
dc.language.iso | eng | en_US |
dc.title | Stellar 3-D kinematics in the Draco dwarf spheroidal galaxy | en_US |
dc.type | Article | - |
dc.identifier.doi | 10.1051/0004-6361/201935613 | en_US |
dc.identifier.scopus | 2-s2.0-85082016819 | en_US |
dc.identifier.isi | WOS:000506032100001 | en_US |
dc.identifier.url | https://www.aanda.org/articles/aa/full_html/2020/01/aa35613-19/aa35613-19.html | en_US |
dc.identifier.url | http://arxiv.org/abs/1904.04037v2 | en_US |
dc.relation.medium | STAMPA | en_US |
dc.relation.volume | 633 | en_US |
dc.relation.firstpage | A36 | en_US |
dc.type.referee | REF_1 | en_US |
dc.description.international | sì | en_US |
dc.relation.scientificsector | FIS/05 - ASTRONOMIA E ASTROFISICA | en_US |
dc.relation.journal | ASTRONOMY & ASTROPHYSICS | en_US |
dc.type.miur | 262 Articolo in rivista | - |
dc.identifier.adsbibcode | 2020A&A...633A..36M | 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.dept | O.A. Padova | - |
crisitem.author.orcid | 0000-0001-8892-4301 | - |
crisitem.author.orcid | 0000-0002-9760-6249 | - |
crisitem.journal.journalissn | 0004-6361 | - |
crisitem.journal.ance | E016240 | - |
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File | Descrizione | Dimensioni | Formato | |
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1904.04037.pdf | postprint | 1.63 MB | Adobe PDF | Visualizza/apri |
aa35613-19.pdf | Pdf editoriale | 1.53 MB | Adobe PDF | Visualizza/apri |
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