The Sagittarius stream with Gaia data

T. Antoja, P. Ramos, C. Mateu, A. Helmi, A. Castro-Ginard, F. Anders, C. Jordi, J. A. Carballo-Bello, E. Balbinot, J. M. Carrasco

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The in-fall of the Sagittarius Dwarf Spheroidal (Sgr) has possibly been responsible of important perturbations on the Milky Way (MW) disk. Yet, with only some thousand of line-of-sight velocities and very few astrometric measurements, there are still many open questions regarding its orbit and stellar content, which hinders our ability to constrain its effects on the MW. We present the largest sample of Sagittarius dwarf and stream stars available to date, obtained entirely by searching in the Gaia DR2 proper motions. Thanks to a smart use of the Gaia Archive combined with the Wavelet Transform to detect substructure, we have unveiled the stream and its proper motion in an almost 360° of its path on the sky, being the more extended and continuous proper motion sequence ever measured for a stream. We have also obtained a sample of RR Lyrae in the stream for which we gain access to the distances and, therefore, to the tangential velocities for the first time. We show the main kinematic and population characteristics of the stream derived in our study. A first comparison with one of the most successful models of the stream shows significant kinematical differences with the data. Our data will allow us to study the detailed the populations of Sgr, obtain the best possible fit to the MW potential from its orbit and, in turn, constrain its impact on our Galaxy.
Original languageEnglish
Publication statusPublished - 1-Jul-2020
EventEA XIV.0 Reunión Científica - online scientific meeting
Duration: 13-Jul-202015-Jul-2020


ConferenceEA XIV.0 Reunión Científica

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