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http://hdl.handle.net/20.500.12386/25048
Title: | The Carina Project. X. On the Kinematics of Old and Intermediate-age Stellar Populations1,2 | Authors: | FABRIZIO, Michele Bono, G. NONINO, Mario Łokas, E. L. Ferraro, I. Iannicola, G. Buonanno, R. CASSISI, Santi Coppola, G. DALL'ORA, Massimo Gilmozzi, R. MARCONI, Marcella Monelli, M. Romaniello, M. Stetson, P. B. Thévenin, F. Walker, A. R. |
Issue Date: | 2016 | Journal: | THE ASTROPHYSICAL JOURNAL | Number: | 830 | Issue: | 2 | First Page: | 126 | Abstract: | We present new radial velocity (RV) measurements of old (horizontal branch) and intermediate-age (red clump) stellar tracers in the Carina dwarf spheroidal. They are based on more than 2200 low-resolution spectra collected with VIMOS at Very Large Telescope (VLT). The targets are faint (20 ≲ V ≲ 21.5 mag), but the accuracy at the faintest limit is ≤9 km s<SUP>-1</SUP>. These data were complemented with RV measurements either based on spectra collected with FORS2 and FLAMES/GIRAFFE at VLT or available in the literature. We ended up with a sample of 2748 stars and among them, 1389 are candidate Carina stars. We found that the intermediate-age stellar component shows a well-defined rotational pattern around the minor axis. The western and the eastern side of the galaxy differ by +5 and -4 km s<SUP>-1</SUP> when compared with the main RV peak. The old stellar component is characterized by a larger RV dispersion and does not show evidence of the RV pattern. We compared the observed RV distribution with N-body simulations for a former disky dwarf galaxy orbiting a giant Milky Way-like galaxy. We rotated the simulated galaxy by 60° with respect to the major axis, we kept the observer on the orbital plane of the dwarf and extracted a sample of stars similar to the observed one. Observed and predicted {V}<SUB>{rot</SUB>}/σ ratios across the central regions are in remarkable agreement. This evidence indicates that Carina was a disky dwarf galaxy that experienced several strong tidal interactions with the Milky Way. Owing to these interactions, Carina transformed from a disky to a prolate spheroid and the rotational velocity transformed into random motions. | URI: | http://hdl.handle.net/20.500.12386/25048 | URL: | https://iopscience.iop.org/article/10.3847/0004-637X/830/2/126 | ISSN: | 0004-637X | DOI: | 10.3847/0004-637X/830/2/126 | Bibcode ADS: | 2016ApJ...830..126F | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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Fabrizio_2016_ApJ_830_126.pdf | PDF editoriale | 3.18 MB | Adobe PDF | View/Open |
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