Related papers: IMF radial gradients in most massive early-type ga…

We present a uniform analysis of the stellar initial mass function (IMF) from integrated light spectroscopy of 15 compact stellar systems (11 globular clusters in M31 and 4 ultra compact dwarfs in the Virgo cluster, UCDs) and two brightest…

A number of recent studies have proposed that the stellar initial mass function (IMF) of early type galaxies varies systematically as a function of galaxy mass, with higher mass galaxies having bottom heavy IMFs. These bottom heavy IMFs…

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…

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…

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…

Variations in the stellar initial mass function (IMF) have been invoked to explain the spectroscopic and dynamical properties of early-type galaxies. However, no observations have yet been able to disentangle the physical driver. We analyse…

We present the results of a study of stellar population properties at large galactocentric radii of 14 low-mass early-type galaxies in the Fornax and Virgo clusters. We derive radial profiles of Age, total metallicity [Z/H], and [alpha/Fe]…

Using samples drawn from the Sloan Digital Sky Survey, we study for the first time the relation between large-scale environments (Clusters, Groups and Voids) and the stellar Initial Mass Function (IMF). We perform an observational approach…

There is substantial evidence that the initial mass function (IMF) may be a function of the local star formation conditions. In particular, the IMF is predicted to flatten with increasing local luminosity density, with the formation 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…

This paper revisits the classical Kennicutt method for inferring the stellar initial mass function (IMF) from the integrated light properties of galaxies. The large size, uniform high quality data set from the Sloan Digital Sky Survey DR4…

We conduct a detailed lensing, dynamics and stellar population analysis of nine massive lens early-type galaxies (ETGs) from the X-Shooter Lens Survey (XLENS). Combining gravitational lensing constraints from HST imaging with…

We present new observations of the nuclear star cluster in the central parsec of the Galaxy with the adaptive optics assisted, integral field spectrograph SINFONI on the ESO/VLT. Our work allows the spectroscopic detection of early and late…

We present new evidence for a variable stellar initial mass function (IMF) in massive early-type galaxies, using high-resolution, near-infrared spectroscopy from the Folded-port InfraRed Echellette spectrograph (FIRE) on the Magellan Baade…

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 complexity of constraining the stellar initial mass function (IMF) in early-type galaxies cannot be overstated, given the necessity of both very high signal-to-noise (S/N) data and the difficulty of breaking the strong degeneracies that…

We determine an absolute calibration of stellar mass-to-light ratios for the densest \simeq 3% of early-type galaxies in the local universe (redshift z\simeq 0.08) from SDSS DR7. This sample of \sim 4000 galaxies has, assuming a Chabrier…

In this letter we describe how we use stellar dynamics information to constrain the shape of the stellar IMF in a sample of 27 early-type galaxies from the CALIFA survey. We obtain dynamical and stellar mass-to-light ratios,…

Spectroscopic analyses of gravity-sensitive line strengths give growing evidence towards an excess of low-mass stars in massive early-type galaxies (ETGs). Such a scenario requires a bottom-heavy initial mass function (IMF). However, strong…

We conduct a detailed investigation of the properties of the stellar initial mass function (IMF) in two massive early-type lens galaxies with velocity dispersions of sigma ~245 km/s and sigma ~325 km/s, for which both HST imaging and…