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The catalogue of simulated Milky Way globular cluster streams

» mardi 24 novembre 2020

Proposition de stage au niveau M1.

Proposant : Paola Di Matteo (GEPI).

Subject : The ESA astrometric Gaia mission is providing the astronomical community with positions and velocities for an unprecedented number of stars (∼7 millions stars in the second release, DR2, have complete phase space information). For the first time, we have also access to full six dimensional phase space information for 150 Galactic globular clusters (hereafter GCs), almost the entire GC population of the Milky Way.
These old stellar systems - that are found in all Galactic main components, from the bulge to the old disc up to the Galactic halo - have been orbiting the Galaxy for several billion years. Because of their finite sizes, they suffer of tidal effects generated by the Milky Way potential and, as a consequence, lose stars along their orbital path, giving rise to so called “tidal tails”, spectacular stellar streams of stars that emanate from the GC main body and can extend for several kpc from it. The aim of this project is to use numerical techniques combined with Gaia DR2 data (proper motions, radial velocities, distances and related errors) to produce the first catalogue of simulated Milky Way globular cluster streams. This catalogue can then be used to search for stellar streams in particular regions of the sky, or to help assigning detected streams to their parent GC. Practically, this project will allow the student to acquire the necessary knowledge on : 1) some of the most recent Galactic mass models, 2) basic techniques of numerical orbit integration 3) basic techniques of sanity checks for orbit integrations 4) set up of a restricted 3 body-problem which models the dynamics of the stars in the presence of the GC and Galactic potential 5) numerical integration 6) visualization of the results, and their projection in several observable spaces, such as those provided by Gaia.
The final goal will be to make all the results publicly available to the community through a dedicated webpage.

Other potential subjects for internships, related to Milky Way modelling, are available. Interested candidates can directly address an email to Paola Di Matteo