BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Constraining the Total Mass of M31 with Precision Astrometry DTSTART;VALUE=DATE-TIME:20230321T105500Z DTEND;VALUE=DATE-TIME:20230321T111000Z DTSTAMP;VALUE=DATE-TIME:20241114T092421Z UID:indico-contribution-192@meetings.aip.de DESCRIPTION:Speakers: Ekta Patel (UC Berkeley)\nHigh-precision astrometric data from the Hubble Space Telescope (HST) and Gaia are revolutionizing o ur ability to study the Local Group. Currently\, 6D phase space measuremen ts (3-dimensional position and velocity) are available for a majority of t he Milky Way’s known satellite galaxies and for four (11%) of M31’s sa tellite galaxies. As satellites trace the dark matter halos of their hosts \, often\, the dynamical properties of a given satellite are used to const rain the mass of the Milky Way (MW) or M31. However\, my recent work has s hown that using the 6D phase space information for an ensemble of satellit e galaxies simultaneously can significantly reduce the current factor of t wo uncertainty in the mass range of the MW. In this talk\, I will describe how dynamical properties derived from 6D phase space information of four M31 satellites (M33\, IC 10\, NGC 147\, NGC 185) can be used in combinatio n with state-of-the-art cosmological simulations to statistically estimate the mass of M31\, reducing current uncertainties to 30-60%. Over the next decade\, HST will deliver astrometric data for the remainder of M31’s s atellite population. Applying these methods to the full population of sate llites out to ~300 kpc will yield the most precise and complete M31 mass e stimate to date. This will be a crucial result for interpreting the severi ty of classical small-scale LCDM challenges (i.e. missing satellites\, too -big-to-fail)\, the assembly history of M31\, and the fate of the Local Gr oup.\n\nhttps://iaus379.aip.de/event/20/contributions/192/ LOCATION:Haus H\, Telegrafenberg URL:https://iaus379.aip.de/event/20/contributions/192/ END:VEVENT END:VCALENDAR