Classifying Globular Clusters And Applying Them To Estimate The Mass Of The Milky Way And The New Torus Models Of The Disk Of The Milky Way

We combine the kinematics of 159 globular clusters provided by the Gaia Early Data Release 3(EDR3)with other observational data to classify the GCs,and to estimate the mass of the Milky Way.We use the age-metallicity relation,integrals of motion,action space and the GC orbits to identify the origin of the GCs.We find that 45.3%have formed in situ,while 38.4%may be related to known merger events:Gaia-Sausage-Enceladus,the Sagittarius dwarf galaxy,the Helmi streams,the Sequoia galaxy and the Kraken galaxy.We also further identify three new substructures associated with the Gaia-Sausage-Enceladus.The remaining 16.3%of GCs are unrelated to the known mergers and thought to be from small accretion events.We select 46 GCs which have radii 8.0<r<37.3 kpc and obtain the anisotropy parameter β=0.315-0.049+0.005,which is lower than the recent result using the sample of GCs in Gaia Data Release 2,but still in agreement with it by considering the error bar.By using the same sample,we obtain the MW mass inside the outermost GC as M(<37.3 kpc)=0.423-0.02+0.02× 1012M⊙,and the corresponding M200=1.11-0.18+0.25×1012M⊙.The estimated mass is consistent with the results in many recent studies.We also find that the estimated β and mass depend on the selected sample of GCs.We also used the LAMOST DR8 and Gaia EDR3 crosscertified K-giant star catalogues to try to build a new Torus model of the galactic disk.The catalogue combines the apparent velocity of LAMOST with Gaia’s proper motion with complete sixdimensional phase spatial data.We divide the sky in the direction of the anticenter into several blocks and fit the velocity distribution function separately.The results are iteratively calculated to self-consistent models to obtain the result.Our results are in good agreement with observations in the line-ofsight velocity and the proper motion.In addition,we found that the thick disk of the Milky Way may be hotter and more extended than thought.