The Dark Matter Tidal Stripping History of the Sagittarius Core with N-body simulations

Abstract

The infall of the Sagittarius (Sgr) Dwarf Spheroidal Galaxy in the Milky Way halo is an unique opportunity to understand how the different components of a dwarf galaxy could be tidally removed. In this work, we reconstruct the Sgr core morphology and kinematics on the basis of a model that has already successfully reproduced the Sgr stream. Here we use a very high resolution model that almost resolves individual stars in the Sgr core. It reproduces most of the observed morphology and kinematic properties, without specific fine-tuning. We also show that the dark matter is much more efficiently removed than stars, letting a stellar mass of 10 7 M , and a dark matter mass only twice this value. Dark matter has been almost entirely removed 2.7 Gyr ago, after few pericenter passages. The predicted mass distribution for the Sgr core is confirmed by the kinematics of the three globular clusters that are still attached to Sgr. Finally the model predicts that the Sgr core will be fully disrupted within the next 2 Gyr.

Mass and Age Determination of the LAMOST Data with Different Machine-learning Methods

“…Up to now, although there are many methods to predict the mass and age of stars, their precision and efficiency are still not perfect. We desperately need to make full use of big data to obtain more samples and try more methods to improve the precision of predictions, thus we can then explore both the history of the Galaxy's assembly more effectively, and more properties of the Milky Way such as mass distribution, population structure, and dynamical evolution (e.g., Wang et al 2018aWang et al , 2018bWang et al , 2019Wang et al , 2020aWang et al , 2020bWang et al , 2020cWang et al , 2022aWang et al , 2022bBland-Hawthorn et al 2019;Yu et al 2021;Yang et al 2022) and references therein).…”