Old low-metallicity (“metal-poor”) stars provide us a unique window to explore the early evolution and formation of our Milky Way as well as the early nucleosynthesis in the universe. In this talk, I would like to introduce the art of Galactic archaeology with metal-poor stars, mainly using the joint efforts between LAMOST and Subaru in the past few years as an example. A homogeneous high-pre...
Galaxy survey provides an important window for the exploration of fundamental physics by accurately mapping the large-scale structure of the Universe (LSS), which is expected to lead to great scientific discoveries. In cosmology, LSS encodes abundant key cosmological information (e.g., baryon acoustic oscillations, neutrino masses, primordial non-Gaussianities, gravity properties, and cosmologi...
Extended regions of accretion disks around supermassive black holes in bright AGNs are prone to gravitational instability, star formation and stellar dynamical evolution with feedback to the disks' structure. Spectroscopic data provide vital clues on the stellar and residual black hole populations. Their dynamical interaction with each other, their natal disks, and other massive companions in a...
The accurate determination of stellar parameters in M-type stars holds significant importance in various astronomical studies. In our study, we employed a transfer learning method coupled with PHOENIX synthetic spectra to estimate fundamental atmospheric parameters (Teff, log g, [M/H], [α/M]) and radial velocities (RV) for an extensive dataset encompassing 581,778 M dwarfs obtained from the Lo...
Microquasars are the compact objects generally including accreting black holes which produce relativitic jets. The physical mechanisms of jet launching, collimation, and acceleration are poorly understood. Microquasars show strong variability in multi-wavelength observations. In X-rays, the sources show the fast variation features up to millisecond time scales, with the prominant quasiperiodic ...