ABSTRACT
Massive galaxies usually observed as symmetric stellar motions and can be fitted well by the commonly used symmetric dynamical models. However, the stellar kinematics of many low-mass galaxies typically contain lots of small patches, causing the stellar second moment of velocity distribution to be non-smooth in small-scales and far from symmetry, we call these patches kinematical small-scale fluctuations. The kinematical fluctuations can easily be mistaken for measurement uncertainties and have not been well discussed. In addition, it is also needed to investigate whether all the centrosymmetric dynamical models introduce a bias in the dynamical mass estimate, especially for low-mass galaxies where kinematical fluctuation degrees are usually very high.
In this talk, I will discuss our recent studies on kinematical fluctuations. We used the comparison of observations and numerical simulations to demonstrate the existence of kinematical fluctuations beyond uncertainties. For the first time we have found that the fluctuation degrees have an approximate inverse log-linear relation with the galaxy stellar surface mass densities. Our results further indicates that stellar motion in galaxies has inherent asymmetry besides external environment influences. In addition, our second work indicates that the kinematical small-scale fluctuations of galaxies do not affect the estimation of the overall dynamical mass of galaxies, even for low-mass galaxies.
BIO
Zehao Zhong is now a postdoc at University of Chinese Academy of Sciences. He obtained his PhD from NAOC in 2024. His research mainly focuses on the kinematics and dynamics of galaxies, dark matter content of galaxies, the integral field spectrograph (IFS) surveys of galaxies, and also the numerical simulation of galaxies.
Host: Junkai Zhang
