Related papers: Stellar velocity distributions in binary-rich ultr…
Binary stars have been shown to have a substantial impact on the integrated light of stellar populations, particularly at low metallicity and early ages - conditions prevalent in the distant Universe. But the fraction of stars in stellar…
Measurements of interstellar absorption lines in 18 ultraluminous infrared galaxies (ULIGs) have been combined with published data, in order to reassess the dependence of galactic outflow speeds on starburst luminosity and galactic mass.…
Significant progress has been made toward understanding the formation of massive ($M > 8~$M$_{\odot}$) binaries in close orbits. For example, the detection of a very low velocity dispersion among the massive stars in the young region M17…
Binary fraction and orbital characteristics provide indications on the conditions of star formation, as they shed light on the environment they were born in. Multiple systems are more common in low density environments rather than in higher…
The vertical density distribution of stars in a galactic disc is traditionally obtained by assuming an isothermal vertical velocity dispersion of stars. Recent observations from SDSS, LAMOST, RAVE, Gaia etc show that this dispersion…
The Milky Way ultra-faint dwarf galaxies (UFDs) contain some of the oldest, most metal-poor stars in the Universe. We present [Mg/Fe], [Si/Fe], [Ca/Fe], [Ti/Fe], and mean [alpha/Fe], abundance ratios for 61 individual red giant branch stars…
We investigate the nature of Ultra Faint dwarf spheroidal galaxies (UF dSphs) in a general cosmological context, simultaneously accounting for various "classical" dSphs and Milky Way (MW) properties, including their Metallicity Distribution…
We use a combination of N-body simulations of the hierarchical clustering of dark matter and semi-analytic modelling of the physics of galaxy formation to probe the relationship between the galaxy distribution and the mass distribution. The…
Galaxies in the Universe are distributed in a web-like structure characterised by different large-scale environments: dense clusters, elongated filaments, sheetlike walls, and under-dense regions, called voids. The low density in voids is…
Milky Way dwarf spheroidal galaxies are the tiniest observed galaxies and are currently associated with the largest fractions of dark matter, which is revealed by their too large velocity dispersions. However, most of them are found near…
We show that the observed upper bound on the line-of-sight velocity dispersion of the stars in an early-type galaxy, sigma<400km/s, may have a simple dynamical origin within the LCDM cosmological model, under two main hypotheses. The first…
Dwarf galaxies have a wide variety of structures, such as dark matter (DM) distribution, stellar-to-halo mass ratio, and stellar density. Recent high-resolution simulations have shown a variety of stellar-to-halo mass ratios for dwarf…
We use spectral energy distribution (SED) fitting to place constraints on the stellar population properties of 29 quiescent ultra-diffuse galaxies (UDGs) across different environments. We use the fully Bayesian routine PROSPECTOR coupled…
Using high-resolution collisionless N-body simulations we study the properties of tidal tails formed in the immediate vicinity of a two-component dwarf galaxy evolving in a static potential of the Milky Way (MW). The stellar component of…
The local space density of galaxies as a function of their basic structural parameters -luminosity, surface brightness and scale size- is still poorly known. Our poor knowledge is the result of strong selection biases against low surface…
The formation of massive stars is one of the major unsolved problems in stellar astrophysics. However, only few if any of these are found as single stars, on average massive stars have more than one companion. Many of them are born in dense…
Now almost 70 years since its introduction, the effective or half-light radius has become a very popular choice for characterising galaxy size. However, the effective radius measures the concentration of light within galaxies and thus does…
Ultra-compact dwarf galaxies (UCDs) are stellar systems with masses of around 10^7 to 10^8 Msun and half mass radii of 10-100 pc. They have some properties in common with massive globular clusters, however dynamical mass estimates have…
We derive an accurate mass estimator for dispersion-supported stellar systems and demonstrate its validity by analyzing resolved line-of-sight velocity data for globular clusters, dwarf galaxies, and elliptical galaxies. Specifically, by…
Galaxy cluster masses, rich with cosmological information, can be estimated from internal dark matter (DM) velocity dispersions, which in turn can be observationally inferred from satellite galaxy velocities. However, galaxies are biased…