Lunch talk on Oct. 21, 2024

Gas accretion in galaxy ecosystem

Speaker: Min Bao (NJU)

Venue: SWIFAR Building 2111

Time: 12:45 PM, Monday, Oct. 21, 2024

Abstract: 

Gas accretion, a key process in galaxy evolution, supplies material for star formation and black hole growth. Galaxies with misaligned or counter-rotating kinematics are believed to form through gas accretion. We collected a sample of 101 galaxies from the MaNGA survey with counter-rotating stellar disks. Our findings indicate that the kinematics of these galaxies can be classified into four different types, each following different formation scenarios, but all attributable to gas accretion. The key factor in the formation scenarios is the efficiency of angular momentum consumption. We also conducted spatially resolved studies on three individual galaxies from the counter-rotating sample, each representative of one type. The results of spectral decomposition and empirical relations further support the formation scenarios attributed to gas accretion. Moreover, we collected a sample of 496 galaxies from the MaNGA survey with kinematic misalignment between gas and stars. By comparing the gas and stellar spins of these galaxies with the large-scale structure (LSS), we found that gas spin tends to be perpendicular to the LSS, while such a tendency disappears for stellar spin. This indicates that the LSS supplies gas for the misaligned galaxies.

Report PPT:  SWIFAR_Min Bao.pdf