Statistical Confirmation of a Stellar Upper Mass Limit

Abstract

We derive the expectation value for the maximum stellar mass (m_max) in an ensemble of N stars, as a function of the IMF upper-mass cutoff (m_up) and N. We statistically demonstrate that the upper IMF of the local massive star census observed thus far in the Milky Way and Magellanic Clouds clearly exhibits a universal upper mass cutoff around 120 - 200 M_sun for a Salpeter IMF, although the result is more ambiguous for a steeper IMF.