and of elliptical galaxies and the initial mass function
L. Angeletti and
Received 7 May 1996 / Accepted 7 October 1996
The observed trend of mass-to-light ratio versus elliptical galaxy mass M has been interpreted in various ways by different authors in recent years. We explore in greater detail than previously done the hypothesis that the mentioned trend can be ascribed to a systematic change of the initial mass function (IMF) with M. We use a three-segment power-law IMF with mass exponents , and for stellar masses m (in ) in the ranges , , and , respectively. The exponent is considered as a free parameter in the range , while and are determined using relations versus M and versus M as constraints. We find that , irrespectively of whether the bottom IMF exponent varies from a flat to a very steep behaviour. We single out a number of realistic solutions; for all of them d /dlog . On the other hand, solutions with , and variable with M are to be excluded, being at variance with the observed relationship. We confirm that a variable single-slope IMF is not a very appealing solution since it requires a minimum stellar mass .
Key words: galaxies: elliptical and lenticular - elliptical galaxies: fundamental plane and metallicity
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© European Southern Observatory (ESO) 1997
Online publication: June 30, 1998