Related papers: The Initial Mass Function of Stars
The stellar initial mass function (IMF) is an essential input for many astrophysical studies but only in a few cases it has been determined over the whole cluster mass range, limiting the conclusions about its nature. The 25 Orionis group…
Several independent lines of evidence suggest that the stellar initial mass function (IMF) in early-type galaxies becomes increasingly `bottom-heavy' with increasing galaxy mass and/or velocity dispersion, sigma. Here we consider evidence…
The dependence of the stellar initial mass function (IMF) on star-formation environment, particularly at low metallicities and high redshifts, remains poorly constrained. Ultra-faint dwarf galaxies (UFDs) are local fossils of high-redshift…
Gaseous and stellar metallicities in galaxies are nowadays routinely used to constrain the evolutionary processes in galaxies. This requires the knowledge of the average yield per stellar generation, $y_{\text{Z}}$, i.e. the quantity of…
The initial mass function (IMF) is a construct that describes the distribution of stellar masses for a newly formed population of stars. It is a fundamental element underlying all of star and galaxy formation, and has been the subject of…
We present models for the initial mass function (IMF) for stars forming within molecular clouds. These models use the idea that stars determine their own masses through the action of powerful stellar outflows. This concept allows us to…
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…
The heavyweight stellar initial mass function (IMF) observed in the cores of massive early-type galaxies (ETGs) has been linked to formation of their cores in an initial swiftly-quenched rapid starburst. However, the outskirts of ETGs are…
Three component models of the IMF are made to consider possible origins for the observed relative variations in the numbers of brown dwarfs, solar-to-intermediate mass stars, and high mass stars. Three distinct physical processes are noted.…
We explore the stellar initial mass function (IMF) of a sample of 49 massive quiescent galaxies (MQGs) at 0.9$<$z$<$1.5. We base our analysis on intermediate resolution spectro-photometric data in the GOODS-N field taken in the…
Crucial for star formation is the interplay between gravity and turbulence. The observed cloud virial parameter, $\alpha_{\mathrm{vir}}$, which is the ratio of twice the turbulent kinetic energy to the gravitational energy, is found to vary…
If all stars form in clusters and both the stars and the clusters follow a power law distribution which favours the creation of low mass objects, then the numerous low mass clusters will be deficient in high mass stars. Therefore, the mass…
We review star formation in molecular clouds and describe why magnetic fields may be important and how they can influence filamentary structure and the column density probability distribution function (PDF). We also comment on the origin of…
The current knowledge on the stellar IMF is documented. It appears to become top-heavy when the star-formation rate density surpasses about 0.1Msun/(yr pc^3) on a pc scale and it may become increasingly bottom-heavy with increasing…
In the last decade, growing evidence has emerged supporting a non-universal stellar Initial Mass Function (IMF) in massive galaxies, with a larger number of dwarf stars with respect to the Milky-Way (bottom-heavy IMF). However, a consensus…
Observational and theoretical arguments increasingly suggest that the initial mass function (IMF) of stars may depend systematically on environment, yet most galaxy formation models to date assume a universal IMF. Here we investigate…
Observations of both galaxies in the distant Universe and local starbursts are showing increasing evidence for very hard ionizing spectra that stellar population synthesis models struggle to reproduce. Here we explore the effects of the…
The most metal-poor stars record the earliest metal enrichment triggered by Population III stars. By comparing observed abundance patterns with theoretical yields of metal-free stars, physical properties of their first star progenitors can…
Observational studies are showing that the galaxy-wide stellar initial mass function are top-heavy in galaxies with high star-formation rates (SFRs). Calculating the integrated galactic stellar initial mass function (IGIMF) as a function of…
Given a flurry of recent claims for systematic variations in the stellar initial mass function (IMF), we carry out the first inventory of the observational evidence using different approaches. This includes literature results, as well as…