Related papers: Stellar Populations
A critical issue in studying the evolution of galaxy clusters is to find ways that enable meaningful comparisons of clusters observed at different redshifts, as well as in various stages of their growth. Studies in the past have typically…
Our uncertainties about binary star systems (and triples and so on) limit our capabilities in literally every single one of the Thematic Areas identified for Astro2020. We need to understand the population statistics of stellar multiplicity…
We compare the growth in stellar mass of galaxies in the $6<z<12$ epoch with predictions of a semi-analytic galaxy formation model - Galacticus. In contrast to diverse and controversial results that compare models and data for the…
The evolution of the galaxy stellar mass function is especially useful to test the current model of galaxy formation. Observational data have revealed a few inconsistencies with predictions from the $\Lambda {\rm CDM}$ model. For example,…
The Spitzer Space Telescope is devoting a significant fraction of the observing time to multi-wavelength cosmological surveys of different depths in various low-background sky regions. Several tens of thousand mid-IR galaxies have been…
I present the latest results from our group about the multiple stellar populations in the old Milky Way globular clusters (GCs) and in the young systems both in the Magellanic Clouds and in the Milky Way. For the ancient GCs in our Galaxy I…
Massive galaxies, such as nearby ellipticals, have relatively low number densities, yet they host the majority of the stellar mass in the universe. Understanding their origin is a central problem of galaxy formation. Age dating of stellar…
Blue straggler stars present as secure members in the Galactic open clusters form a major challenge to the conventional picture of evolutionary population synthesis based on the stellar evolution theory of single stars, as illustrated in…
The use of roman numerals for stellar populations represents a classification approach to galaxy formation which is now well behind us. Nevertheless, the concept of a pristine generation of stars, followed by a protogalactic era, and…
I describe some of the current challenges in galaxy formation theory with applications to formation of disks and of spheroids. Forthcoming deep surveys of galaxies with Keck and VLT will provide high quality spectra of $\sim 10^5$ galaxies…
Spectral evolution models are a widely used tool for determining the stellar content of galaxies. I provide a review of the latest developments in stellar atmosphere and evolution models, with an emphasis on massive stars. In contrast to…
It is now commonly accepted that globular clusters (GCs) have undergone a complex formation and that they host at least two stellar generations. This is a recent paradigm and is founded on both photometric and spectroscopic evidence. We…
The formation of massive stars is an outstanding problem in stellar evolution. However, it is expected that they are (predominantly) born in heirarchical environments within massive young clusters, which in turn are located within larger…
The development and progress of the studies of winds and mass loss from hot stars, from about 1965 up to now, is discussed in a personal historical perspective. The present state of knowledge about stellar winds, based on papers presented…
Star clusters are among the first celestial objects catalogued by early astronomers. As simple and coeval populations, their study has been instrumental in charting the properties of the Milky Way and providing insight into stellar…
We present an analysis of the spatial distribution of various stellar populations within the Large and Small Magellanic Clouds. We use optically selected stellar samples with mean ages between ~9 and ~1000 Myr, and existing stellar cluster…
The details of bulge formation via collapse, mergers, secular processes or their interplay remain unresolved. To start answering this question and quantify the importance of distinct mechanisms, we mapped a sample of three galactic bulges…
Combining population synthesis models with simple Montecarlo simulations of stochastic effects in the number of stars occupying sparsely populated stellar evolutionary phases in the HRD, I show that the scatter observed in the photometric…
Globular clusters were thought to be simple stellar populations, but recent photometric and spectroscopic evidence suggests that the clusters' early formation history was more complicated. In particular, clusters show star-to-star abundance…
(abridged) This thesis presents theoretical and statistical techniques broadly related to systems of dynamically-interacting particles composed of several different types of populations. They are applied to observations of dense star…