Shedding light on galaxy rotation secrets
The dichotomy concerns the so-called angular momentum (per unit mass) that in physics is a measure of size and rotation velocity. Spiral galaxies are found to be strongly rotating, with an angular momentum higher by a factor of about five than ellipticals. What is the origin of such a difference? An international research team investigated the issue in a study just published in the Astrophysical Journal. The team was led by SISSA Ph.D. student JingJing Shi under the supervision of Prof. Andrea Lapi and Luigi Danese, and in collaboration with Prof. Huiyuan Wang from USTC (Hefei) and Dr. Claudia Mancuso from IRA-INAF (Bologna). The researchers inferred from observations the amount of gas fallen into the central region of a developing galaxy, where most of the star formation takes places.