The Stellar Initial Mass Function

恒星形成的结果是具有一定质量范围的恒星和亚恒星物体。天体物理学家把质量的分布称为初始质量函数（IMF）。IMF与恒星形成速率的时间调制一起决定了星系和星团的演化和命运，因此是一个基本的天体物理分布函数。由于恒星不能直接称重，恒星形成区域和整个星系的IMF形状仍然不确定。这里概述的项目解决了以下问题：(i)在整个星系中整合的恒星IMF的形式和时变及其在宇宙时间尺度上的化学光度演化和红移相关超新星速率的含义，（ii）最大恒星质量的存在，（iii）大质量恒星的IMF形状和高恒星多样性的修正，以及（iv）使用新颖迭代方案的低质量恒星的MF形状。(v) IMF在氢燃烧质量极限和褐矮星质量范围内的可能形状和变化。因此，该项目涉及的问题范围从宇宙学问题一直到恒星和亚恒星状态下的局部恒星形成。

The outcome of star formation are stars and sub-stellar objects with a range of masses. Astrophysicists refer to the distribution of masses as the initial mass function (IMF). The IMF together with the time-modulation of the star-formation rate dictates the evolution and fate of galaxies and star clusters, and is therefore a fundamental astrophysical distribution function. Because stars cannot be weighed directly the shape of the IMF in star-forming regions and in entire galaxies remains uncertain. The project outlined here addresses the following issues: (i) the form and time-variation of the stellar IMF integrated over whole galaxies and the implications for their chemo-photometric evolution over cosmological time scales and the red-shift dependent supernova rate, (ii) the existence of a maximum stellar mass, (iii) the shape of the IMF for massive stars and corrections for a high stellar multiplicity, and (iv) the shape of the MF for low-mass stars using a novel iterative scheme, and (v) the possible shape and variation of the IMF across the hydrogen-burning mass limit and in the brown-dwarf mass regime. This project thus deals with issues ranging from cosmological problems down to local star-formation in the stellar and sub-stellar regimes.