恒星形成星系主序关系的研究现状

Observations have found that for star-forming galaxies (SFGs) there is a relatively tight relation between star formation rate (SFR) and stellar mass (M) (i.e. lg SFR-lg M,known as main sequence), with a typical scatter of 0.2 0.4 dex. The main sequence playsan important role in constraining theoretical models of galaxy evolution and is one of thebasic relations describing the evolution of galaxies. Recent years we have witnessed greatprogress in both observational and theoretical work on the main sequence and its evolution.Firstly, the key steps involved in the process of obtaining the main sequence are introduced,focusing on the method of measuring SFR of galaxy and the method of selecting the SFGsfrom the complete sample of galaxies. Using different methods causes systematic deviationsbetween the obtained main sequence. Then the main issues and progress on the studies ofthe main sequence are presented. The main sequence shows a bending at massive end withrespect to the slope obtained in the low-mass end. There are mainly two explanations forbending, including the formation of a bulge component in SFGs and the lessening of coldaccretion. The relation between the scatter of main sequence and the stellar mass (SFR-M)shows the characteristic of U-shape. This may indicate that supernovae feedback increasesthe scatter at low-mass end and active galactic nuclei feedback is important for increasingthe scatter at massive end. In addition, in the mid- and high-redshift, the normalizationof the main sequence obtained by theory is always lower than the observational result by0.2 0.5 dex. So far, this problem has not been effectively solved. The high-redshift SFGsdata from JWST can help us understand main sequence more comprehensively