The emergence of the galactic stellar mass function from a non-universal IMF in clusters

¹ Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, 2100 Copenhagen, Denmark
e-mail: sami.dib@gmail.com
² Department of Physics and Astronomy, University of Western Ontario, London, Ontario N6A 3K7, Canada

Received: 18 December 2017
Accepted: 9 February 2018

Abstract

We investigate the dependence of a single-generation galactic mass function (SGMF) on variations in the initial stellar mass functions (IMF) of stellar clusters. We show that cluster-to-cluster variations of the IMF lead to a multi-component SGMF where each component in a given mass range can be described by a distinct power-law function. We also show that a dispersion of ≈0.3 M_⊙ in the characteristic mass of the IMF, as observed for young Galactic clusters, leads to a low-mass slope of the SGMF that matches the observed Galactic stellar mass function even when the IMFs in the low-mass end of individual clusters are much steeper.