Speaker
Oliver Pfuhl
(MPE)
Description
I will present the star formation history of the Milky Way's nuclear star cluster. We used spectroscopically derived temperatures of 450 cool giant stars within 1 pc from Sgr A* to construct a Hertzsprung–Russell diagram of the Galactic Center stellar population. By fitting the observed diagram with model populations we were able to derive the star formation history of the nuclear cluster.
We find (1) that the average nuclear star formation rate dropped from an initial maximum ~10 Gyrs ago to a deep minimum 1–2 Gyr ago and increased again during the last few hundred Myrs, (2) that roughly 80% of the stellar mass formed more than 5 Gyrs ago, and (3) that mass estimates within R ~ 1 pc from Sgr A* favor a dominant star formation mode with a "normal" Chabrier/Kroupa initial mass function for the majority of the past star formation in the GC.
Author
Oliver Pfuhl
(MPE)