The formation of ultra-diffuse galaxies (UDGs) is not well-understood. UDGs have large sizes (several kpc) for their dwarf-galaxy-like stellar mass and have a wide range in dark matter content and other observed properties. In particular, NGC1052-DF2 and NGC1052-DF4 are two puzzling UDGs: they have low-velocity dispersions indicating little to no dark matter content, as well as overly luminous ...
Galaxy structures are fossil records of their assembly history. Modern IFU spectrographs offer the ability to map the spatial distribution of the motions, ages, and chemical abundances of stars in galaxies, which provide unprecedented detailed view of galaxies structures. But the information are still blended along the line-of-sight. Decomposition of galactic structures in a physical way is cha...
A grand challenge for modern astrophysics is to understand star and galaxy formation in the first billion years of cosmic history. In particular, the first generation of stars born in extremely metal-poor/free primordial gas, the so-called population III (Pop III), are believed to have distinct features compared with present-day stars: They are more likely to become massive black holes due thei...
I will discuss some recent progress in 21cm line intensity mapping within the SKA cosmology science working group. In particular, we report the first direct detection of the cosmological power spectrum using 21cm line (2301.11943), derived from interferometric observations with the L-band receivers of the MeerKAT radio telescope. I review the challenges in analysing the MeerKAT data and present...
At the heart of every galaxy cluster is the brightest central galaxy (BCG). The central location of the BCG along with its unique formation history yield the underlying galaxy-dark matter halo connection. This statistical correlation allows us to enhance our understanding of the assembly and evolution of BCGs over cosmic time. However, we gain further insight into the formation and evolution of...