Solo dwarfs – III. Exploring the orbital origins of isolated Local Group galaxies with Gaia Data Release 2
| Autor: | Giuseppina Battaglia, Kim A. Venn, Clare Higgs, Alan W. McConnachie, Geraint F. Lewis, Patrick Côté, G. F. Thomas |
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| Rok vydání: | 2020 |
| Předmět: |
Physics
010308 nuclear & particles physics Milky Way FOS: Physical sciences Local Group Astronomy and Astrophysics Astrometry Astrophysics Astrophysics - Astrophysics of Galaxies 01 natural sciences Galaxy Red-giant branch Leo A Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences Eridanus 010303 astronomy & astrophysics Dwarf galaxy |
| Zdroj: | Monthly Notices of the Royal Astronomical Society. 501:2363-2377 |
| ISSN: | 1365-2966 0035-8711 |
| Popis: | We measure systemic proper motions for distant dwarf galaxies in the Local Group and investigate if these isolated galaxies have ever had an interaction with the Milky Way or M31. We cross-match photometry of isolated, star forming, dwarf galaxies in the Local Group, taken as part of the {\it Solo} survey, with astrometric measurements from Gaia Data Release 2. We find that NGC 6822, Leo A, IC 1613 and WLM have sufficient supergiants with reliable astrometry to derive proper motions. An additional three galaxies (Leo T, Eridanus 2 and Phoenix) are close enough that their proper motions have already been derived using red giant branch stars. Systematic errors in Gaia DR2 are significant for NGC 6822, IC 1613 and WLM. We explore the orbits for these galaxies, and conclude that Phoenix, Leo A and WLM are unlikely to have interacted with the Milky Way or M31, unless these large galaxies are very massive ($\gtrsim 1.6 \times 10^{12}\,M_\odot$). We rule out a past interaction of NGC 6822 with M31 at $\sim 99.99\%$ confidence, and find there is a $ 15 pages, 7 figures. Accepted for publication in MNRAS. Corrected Figure 4 and 5 |
| Databáze: | OpenAIRE |
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