Related papers: The Initial Mass Function of Lens Galaxies from Qu…
The stellar initial mass function (IMF) in star clusters is reviewed. Uncertainties in the observations are emphasized. We suggest there is a distinct possibility that cluster IMFs vary systematically with density or pressure. Dense…
Recent determinations of the upper mass limit to the local initial mass function (IMF) claim a value of m(upper)=50+/-10 solar masses, based upon direct comparisons of the observed oxygen and iron abundances in metal-poor stars with the…
This work studies microlensing effects in strongly lensed gravitational wave (GW) signals corresponding to global minima images in galaxy-scale lenses. We find that stellar microlenses alone are unable to introduce noticeable wave effects…
A Bayesian statistical formalism is developed to quantify the level at which the mass function slope (alpha) and the projected cumulative mass fraction (f) of (CDM) substructure in strong gravitational-lens galaxies, with arcs or Einstein…
Some theories of star formation suggest massive stars may only form in clustered environments, which would create a deficit of massive stars in low density environments. Observationally, Massey (2002) finds such a deficit in samples of the…
Strong gravitational lensing observations can provide extremely valuable information on the structure of galaxies, but their interpretation is made difficult by selection effects, which, if not accounted for, introduce a bias between the…
The essential features of the stellar Initial Mass Function are, rather generally, (1) a peak at a mass of a few tenths of a solar mass, and (2) a power-law tail toward higher masses that is similar to the original Salpeter function. Recent…
We develop a general method for analyzing the light curves of microlensed quasars and apply it to the OGLE light curves of the four-image lens Q2237+0305. We simultaneously estimate the effective source velocity, the average stellar mass,…
In this paper we compare two different diagnostics for estimating stellar masses in early-type galaxies and we establish their level of reliability. In particular, we consider the well-studied sample of 15 field elliptical galaxies selected…
The first stars fundamentally transformed the early Universe through their production of energetic radiation and the first heavy chemical elements. The impact on cosmic evolution sensitively depends on their initial mass function (IMF),…
The Initial Mass Function (IMF) of early-type galaxies (ETGs) has been found to feature systematic variations by both dynamical and spectroscopic studies. In particular, spectral line strengths, based on gravity-sensitive features, suggest…
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…
Observations have not yielded convincing results concerning the form of the stellar initial mass function (IMF) or its variations in space and time, so it is proposed that theoretical models may provide useful guidance. Several classes of…
We here present the first spatially-resolved study of the IMF in external galaxies derived using a dynamical tracer of the mass-to-light ratio. We use the kinematics of relaxed molecular gas discs in seven early-type galaxies (ETGs)…
Quasar microlensing is both a very useful tool in cosmology and astrophysics, and a source of uncertainty in some studies like the determination of the Hubble constant from lensed quasars. Microlensing probability and time-scales have been…
A universal stellar initial mass function (IMF) should not be expected from theoretical models of star formation, but little conclusive observational evidence for a variable IMF has been uncovered. In this paper, a parameterization of the…
We present a pilot method to estimate the high-mass initial mass function (IMF) across the arm, interarm, and spur regions in galaxies and apply it to NGC 628. We extracted star-forming complexes (SFCs) from H$\alpha$ VLT/MUSE and UVIT (FUV…
It has frequently been suggested that the stellar IMF in galaxies was top-heavy at early times. This would be plausible physically if the IMF depends on a mass scale such as the Jeans mass that was higher at earlier times because of the…
The stellar initial mass function (IMF) describes how many stars form at which mass. Despite recent observational progress, many fundamental properties of the IMF are still unknown. Specifically the question, whether starbursts are biased…
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…