Related papers: The massive star IMF at high metallicity
We show that dynamical evolution in a strong (Galactic Centre-like) tidal field can create clusters that would appear to have very top-heavy IMFs. The tidal disruption of single star forming events can leave several bound `clusters' spread…
We describe the use of our chemical evolution model to reproduce the abundance patterns observed in a catalog of elliptical galaxies from the SDSS DR4. The model assumes ellipticals form by fast gas accretion, and suffer a strong burst of…
We demonstrate the existence of a -local- relation between galaxy surface mass density, gas metallicity, and star-formation rate density using spatially-resolved optical spectroscopy of HII regions in the local Universe. One of the…
The production rate of ionizing photons in young < 8 Myr, unresolved stellar clusters in the nearby irregular galaxy NGC 4214 is probed using multi-wavelength Hubble Space Telescope WFC3 data. We normalize the ionizing photon rate by the…
The hypothesis of a universal initial mass function (IMF) -- motivated by observations in nearby stellar systems -- has been recently challenged by the discovery of a systematic variation of the IMF with the central velocity dispersion,…
The H alpha equivalent width (EW) is the ratio of the H alpha flux to the continuum at 6565{\AA}. In normal star forming galaxies the H alpha flux is dominated by reprocessed photons from stars with masses greater than 10 M_o and the…
We are conducting a deep near-infrared (NIR) imaging survey of young embedded clusters in the extreme outer Galaxy (hereafter EOG), at the Galactic radius (R_g) of more than 18 kpc. The EOG is an excellent laboratory to study the nature of…
(shortened) In this contribution an average or Galactic-field IMF is defined, stressing that there is evidence for a change in the power-law index at only two masses: near 0.5 Msun and 0.08 Msun. Using this supposed universal IMF, the…
The main scope of this paper is to investigate the possible existence of a metallicity dependence of the overshooting from main sequence stars turbulent cores. We focus on objects with masses in the range ~2.5 Msol - ~25 Msol. Basically,…
Understanding the spatial distribution of metals within galaxies allows us to study the processes of chemical enrichment and mixing in the interstellar medium (ISM). In this work, we map the two-dimensional distribution of metals using a…
An analysis of some properties of stellar models as a function of metallicity Z (and helium content Y) is presented, with special attention to those stars with metallicities higher than twice or three times solar. It is shown that the…
We investigate whether a single population of first stars could have influenced both the metal enrichment and reionization of the high-redshift intergalactic medium (IGM), by calculating the generated ionizing radiation per unit metal yield…
We consider the hypothesis that the formation of elliptical galaxies includes a phase in which star formation is mostly restricted to massive stars, with the bias towards high mass stars increasing with elliptical galaxy mass. The mass…
The observed rest-UV luminosity function at cosmic dawn ($z \sim 8-14$) measured by JWST revealed an excess of UV-luminous galaxies relative to many pre-launch theoretical predictions. A high star-formation efficiency (SFE) and a top-heavy…
The presence (and nature) of variations in the stellar initial mass function (IMF) at substantially sub-solar masses and metallicities ($m$$<$0.5M$_{\odot}$, [M/H]$\lesssim$$-$1) remains poorly constrained. Predictions from simulations vary…
We investigate the physical and chemical conditions necessary for low-mass star formation in extragalactic environments by calculating various characteristic timescales associated with star formation for a range of initial conditions. The…
Recent work has suggested that the stellar initial mass function (IMF) is not universal, but rather is correlated with galaxy stellar mass, stellar velocity dispersion, or morphological type. In this paper, we investigate variations of the…
Star formation in the early Universe has left its imprint on the chemistry of observable stars in galaxies. We derive elemental abundances and the slope of the low-mass end of the initial mass function (IMF) for a sample of 25 very massive…
The debate about the universality of the stellar initial mass function (IMF) revolves around two competing lines of evidence. While measurements in the Milky Way, an archetypal spiral galaxy, seem to support an invariant IMF, the observed…
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…