Related papers: The Starburst IMF -- An Impossible Measurement?
From time to time, and quite more frequently in recent years, claims appear favoring a variable Initial Mass Function (IMF), one way or another, either in time or space. In this chapter we add our two pennies of wisdom, illustrating how the…
Recently, there has been great progress toward observationally determining the mean star formation history of the universe. When accurately known, the cosmic star formation rate could provide much information about Galactic evolution, if…
Systematic variations of the IMF in early-type galaxies, and their connection with possible drivers such as velocity dispersion or metallicity, have been much debated in recent years. Strong lensing over galaxy scales combined with…
(abridged) Here we discuss the question whether the extreme circumstances in the centre of the Milky Way may be the reason for a significant variation of the IMF. By means of stellar evolution models using different codes we show that the…
We address the turbulent fragmentation scenario for the origin of the stellar initial mass function (IMF), using a large set of numerical simulations of randomly driven supersonic MHD turbulence. The turbulent fragmentation model…
It is now well-established that the stellar initial mass function (IMF) can be determined from the absorption line spectra of old stellar systems, and this has been used to measure the IMF and its variation across the early-type galaxy…
I briefly review recent observations of regions forming low mass stars. The discussion is cast in the form of seven questions that have been partially answered, or at least illuminated, by new data. These are the following: where do stars…
We have undertaken the largest systematic study of the high-mass stellar initial mass function (IMF) to date using the optical color-magnitude diagrams (CMDs) of 85 resolved, young (4 Myr < t < 25 Myr), intermediate mass star clusters…
The stellar masses, mean ages, metallicities, and star formation histories of galaxies are now commonly estimated via stellar population synthesis (SPS) techniques. SPS relies on stellar evolution calculations from the main sequence to…
It has been shown recently that the dynamical V-band mass-to-light ratios of compact stellar systems with masses from 10^6 to 10^8 Solar masses are not consistent with the predictions from simple stellar population (SSP) models. Top-heavy…
The unexpected high incidence of carbon-enhanced, s-process enriched unevolved stars amongst extremely metal-poor stars in the halo provides a significant constraint on the Initial Mass Function (IMF) in the early Galaxy. We argue that…
Recent studies of dense clumps/cores in a number of regions of low-mass star formation have shown that the mass distribution of these clumps closely resembles the initial mass function (IMF) of field stars. One possible interpretation of…
Recent studies suggest that Swift gamma-ray bursts (GRBs) may not trace an ordinary star formation history. Here we show that the GRB rate turns out to be consistent with the star formation history with an evolving stellar initial mass…
The stellar initial mass function (IMF) is predicted to depend upon the temperature of gas in star-forming molecular clouds. The introduction of an additional parameter, $T_{IMF}$ , into photometric template fitting, suggest most galaxies…
In this paper, basic observational properties of elliptical galaxies such as the integrated spectra, the chemical abundances and the enhancement of $\alpha$-elements inferred from broad-band colors and line strength indices $Mg_2$ and $< Fe…
The question of the variation of the upper IMF at high metallicity is briefly reviewed. I show recent results suggesting a revision in the definition of `high metallicity' in extragalactic H II regions. I present preliminary results…
When estimating the abundances which result from a given star formation event, it is customary to treat the IMF as a series of weight factors to be applied to the stellar yields, as a function of mass, implicitly assuming one is dealing…
A growing fraction of Simple Stellar Population (SSP) models, in an aim to create more realistic simulations capable of including stochastic variation in their outputs, begin their simulations with a distribution of discrete stars following…
The presence (and nature) of variations in the stellar initial mass function (IMF) at substantially sub-solar masses and metallicities ($m$$<$0.5M$_{\odot}$, [M/H]$\lesssim$$-$1) remains poorly constrained. Predictions from simulations vary…
The morphology and kinematics of molecular clouds (MCs) are best explained as the consequence of super--sonic turbulence. Super--sonic turbulence fragments MCs into dense sheets, filaments and cores and large low density ``voids'', via the…