高于阀值时，SFR随表面密度线性增长。
Above that threshold, the SFR increases linearly with that surface density.
一个星系团中星系的表面密度可从其照片上测得。
The surface density of galaxies in a cluster can be measured from photographs.
他们发现恒星只有在表面密度达到一定的阀值时才会较好的形成。
They discovered that star formation is pretty well non-existent until the surface density reaches a certain threshold in parts of the cloud.
应用推荐