Related papers: The massive star IMF at high metallicity
The stellar initial mass function (IMF) is thought to be bottom-heavy in the cores of the most massive galaxies, with an excess of low mass stars compared to the Milky Way. However, studies of the kinematics of quiescent galaxies at 2<z<5…
We use a sample of 87 rest-frame UV-selected star-forming galaxies with mean spectroscopic redshift z=2.26 to study the correlation between metallicity and stellar mass at high redshift. Using stellar masses determined from SED fitting to…
The stellar initial mass function (IMF) plays a crucial role in determining the number of surviving stars in galaxies, the chemical composition of the interstellar medium, and the distribution of light in galaxies. A key unsolved question…
Theoretical arguments and indirect observational evidence suggest that the stellar initial mass function (IMF) may evolve with time, such that it is more weighted toward high mass stars at higher redshift. Here we test this idea by…
The observed mass-to-light ($M/L$) ratios of a large sample of GCs in M31 show an inverse trend with metallicity compared to what is expected from Simple Stellar Population (SSP) models with an invariant canonical stellar IMF, in the sense…
We highlight some results from our detailed abundance analysis study of 703 kinematically selected F and G dwarf stars in the solar neighbourhood. The analysis is based on spectra of high-resolution (R=45000 to 110000) and high…
Recent observations of active galactic nuclei (AGNs) have shown a high Fe~II/Mg~II line-flux ratio in their broad-line regions, nearly independent of redshift up to $z \gtrsim 6$. The high flux ratio requires rapid production of iron in…
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 presence of very massive stars (VMS, masses $>100$ M$_{\odot}$) is now firmly established in the local group, nearby galaxies, and out to cosmological distances. If present, these stars could boost the UV luminosity and ionizing photon…
The number of known planets around intermediate-mass stars (1.5 M$_{\odot}$ < M$_{\star}$ < 3.5 M$_{\odot}$) is rather low. We aim to test whether the correlation between the metallicity of the star and the presence of gas-giant planets…
The gas-phase metallicity of low-mass galaxies increases with increasing stellar mass ($M_\ast$) and is nearly constant for high-mass galaxies. Theory suggests that this tight mass-metallicity relationship is shaped by galactic outflows…
We investigate the time evolution and spatial variation of the stellar initial mass function (IMF) in star-forming disk galaxies by using chemodynamical simulations with an IMF model depending both on local densities and metallicities…
Clusters of galaxies allow a direct estimate of the metallicity and metal production yield on the largest scale so far. The ratio of the total iron mass in the ICM to the total optical luminosity of the cluster (the iron…
The stellar initial-mass function (IMF) represents a fundamental quantity in astrophysics and cosmology, describing the mass distribution of stars from low to very-high masses. It is intimately linked to a wide variety of topics, including…
We provide detailed abundance analyses of 8 candidate super-metal-rich stars. Five of them are confirmed to have [Fe/H] > 0.2 dex, the generally-accepted limit for super-metal-richness. Furthermore, we derive abundances of several elements…
Metallicity is a crucial tracer of galaxy evolution, providing insights into gas accretion, star formation, and feedback. At high redshift, these processes reveal how early galaxies assembled and enriched their interstellar medium. In this…
Resolution of nearby giant HII regions into their stellar and nebular constituents provides fundamental insights for interpreting more distant and powerful starburst activity. The following summarizes recent advances in our understanding of…
We have been investigating the metallicity dependence of star and planet formation, particularly focusing on the outer Galaxy with a Galactocentric distance ($R_g$) of $\gtrsim$15 kpc, where the metallicity is determined to be as low as…
The manner in which the stellar initial mass function (IMF) scales with global galaxy properties is under debate. We use two hydrodynamical, cosmological simulations to predict possible trends for two self-consistent variable IMF…
Statistical sampling from the stellar initial mass function (IMF) for all star-forming regions in the Galaxy would lead to the prediction of ~1000 Msun stars unless there is a rapid turn-down in the IMF beyond several hundred solar masses.…