Although the global picture of the Galactic disk has been well known for decades, lots of fundamental questions about the formation and evolution of the Galactic diskare still open. Only until recently, the large spectroscopic surveys, e.g. SDSS/SEGUE, SDSS III/APOGEE, and LAMOST, with a few hundreds thousands to a few million disk stars unveil more and more details of the disk, taking opportunities to answer some of the questions.

In this talk, I will demonstrate the recent observational chemo-kinematic features of the disk, which help us to better understand how the Galactic disk evolves. Firstly, the SDSS/SEGUIE G-type dwarf stars confirm that the disk is indeed affected by the radial migration, which have been proposed by theorists. The new LAMOST DR2 data reveals more concrete evidences, in the age-metallicity relation map, that when the radial migration occurred and at which radii it significantly mixed the stars. On the other hand, the new observational data also bring some, maybe more, puzzles. I will show you the complicated kinematic/dynamic features recently discovered in the outer disk, e.g., the bi-modalty of the radial velocity distribution in the Galactic anti-center region, the asymmetric bulk motions in both radial and vertical directions, and the strange oscillation in the disk rotation curve. All these evidences are opening new frontiers of the knowledge of the Galactic disk. 

Bio:

Dr. Chao Liu got his PhD degree at NAOC in 2008. As a postdoc, he has been working in the Gaia project for  more than 3 years at Max Planck Institute for Astronomy in Germany. He became a faculty member of NAOC since 2012. He is mainly working in the Milky Way science, including the stellar chemo-dynamics, statistical approaches for stellar classification and parameterization, based on the photometric and spectroscopic surveys. He is also interested in the interstellar medium and the dynamics of the external galaxies.