The Exploration And Research Of Stellar Stream Properties In The Galactic Anticenter Region

The stellar stream is a prominent structure in the Milky Way.It usually represents the structures in the halo,which derive from the dwarf galaxies or globular clusters near the Milky Way that were elongated,torn apart and disintegrated by the tidal force.The stellar streams exist in the Milky Way with large-scale,which require more research topics.Therefore,the stellar streams are considered to be indispensable in the research of the Milky Way’s history.Based on the data obtained from the spectral survey of LAMOST and SDSS,this paper explored and studied the kinematics and metallicities of several structures such as TriAnd,ACS and Monoceros ring.In the paper,we took the K and M giants of LAMOST and the RGB stars of SDSS as the original samples,and obtained the candidate members of the three structures by setting limits through the FoF algorithm.We obtained 128 TriAnd member stars with the assistance of the algorithm,and then analyzed its sample.The distribution of members in space showed that TriAnd is located in the lower part of the disk,and the average distance of member stars is 17.3 kpc.We found that the structure has a protruding substructure in the region of about l=133° on the southern side.A comparison of metallicity with the disk and halo manifested that it likely originated in the thick disk of the Milky Way.The trajectory of TriAnd also showed that it is gradually moving away from the sun.The Monoceros ring and ACS are both on the upper part of the disk.After this selection,we got 132 members of the Monoceros ring and 32 members of the ACS.The distribution of members in space showed that the Monoceros ring and the ACS are adjacent to each other,and the boundary is about 30° in galactic latitude.The orbits of the two structures are close,while the members of the Monoceros ring are farther apart.However,in the study of velocity and metallicity,the difference between them is not significant.Therefore,we inferred that both of them might have a common origin.During the exploration of the anticenter region,we discovered a part of the Sagittarius stream,which belongs to the leading arm of the Sagittarius stream.When it passes through the region where the Monoceros ring is located,due to external influences,the movement directions of some member stars in stream have changed,forming a protruding substructure.