Related papers: The massive star initial mass function of the Arch…
The Initial Mass Function (IMF) for massive galaxies can be constrained by combining stellar dynamics with strong gravitational lensing. However, this method is limited by degeneracies between the density profile of dark matter and the…
The luminosity function (LF) of young star clusters is often approximated by a power law function. For clusters in a wide range of galactic environments this has resulted in fit indices near -2, but on average slightly steeper. A…
A method is presented here for investigating variations in the upper end of the stellar Initial Mass Function (IMF) by probing the production rate of ionizing photons in unresolved, compact star clusters with ages<10 Myr and covering a…
The newly installed Wide Field Camera 3 (WFC3) on the Hubble Space Telescope has been used to obtain multi-band images of the nearby spiral galaxy M83. These new observations are the deepest and highest resolution images ever taken of a…
Using homogeneous CCD photometric data from the 105-cm Kiso Schmidt telescope covering a 50' x 50' field, we study the mass functions (MFs) of nine open clusters. The ages and Galactocentric distances of the target clusters vary from 16 -…
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…
We obtain constraints on the slope of a universal stellar initial mass function (IMF) over a range of cosmic star-formation histories (SFH) using z=0.1 luminosity densities in the range from 0.2 to 2.2 microns. The age-IMF degeneracy of…
We investigate in massive early-type galaxies the variation of their two-dimensional central fraction of dark over total mass and dark matter density as a function of stellar mass, central stellar velocity dispersion, effective radius, and…
A robust stellar initial mass function (IMF) is crucial in any studies related to star formation. However, the direct measurement of the stellar IMF is confined to the local universe, limited by the resolving power of telescopes. Recently,…
Observed variations in the IMF are reviewed with an emphasis on environmental density. The remote field IMF studied in the LMC by several authors is clearly steeper than most cluster IMFs, which have slopes close to the Salpeter value.…
The local stellar mass density is observed to be significantly lower than the value obtained from integrating the cosmic star formation history (SFH), assuming that all the stars formed with a Salpeter initial mass function (IMF). Even…
Observed variations in the slope of the initial stellar mass function are shown to be consistent with a model in which the protostellar gas is randomly sampled from hierarchical clouds at a rate proportional to the square root of the local…
There is good evidence that the centers of massive early-type galaxies have a bottom-heavy stellar initial mass function (IMF) compared to the IMF of the Milky Way. Here we study the radial variation of the IMF within such galaxies, using a…
We present V and I equivalent HST/WFPC2 photometry of two areas in the Large Magellanic Cloud: The southern part of the stellar association LH 52, located on the western edge of the super-shell LMC 4, and a field between two associations,…
We present a new method to analyze the IMF at its high mass end in young stellar clusters, which rely on two integrated observables: the cluster bolometric and Halpha luminosity. Using several cluster samples selected in M33 we show that a…
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…
We present an axially symmetric formula to calculate the probability of finding gravitational arcs in galaxy clusters, being induced by their massive dark matter haloes, as a function of clusters redshifts and virial masses. The formula…
We present a spatially resolved comparison of the stellar-mass and total-mass surface distributions of nine early-type galaxies. The galaxies are a subset of the Sloan Lens ACS survey (or SLACS; Bolton et al. 2006). The total-mass…
We present a new wide field image of the distant cluster AC114 ($z=0.31$) obtained with Wide Field and Planetary Camera II onboard the Hubble Space Telescope. This image considerably extends our knowledge of the lensing properties of the…
Observations of the stellar initial mass function are reviewed. The flattening at low mass is evidence for a characteristic mass in star formation, which could be the minimum stellar mass for the onset of deuterium burning or the thermal…