Related papers: Revisiting the missing mass problem in MOND for ne…
I track the history of star count estimates of the Milky Way field star and open cluster IMFs, concentrating on the neglected mass range from 1 to 15 M${_\odot}$. The prevalent belief in a universal IMF appears to be without basis for this…
Although the stellar initial mass function (IMF) has only been directly determined in star clusters it has been manifoldly applied on galaxy-wide scales. But taking the clustered nature of star formation into account the galaxy-wide IMF is…
Evidence supporting the hypothesis of an invariant stellar Initial Mass Function is strong and varied. The intra-cluster medium in rich clusters of galaxies is one of the few contrary locations where recent interpretations of the chemical…
The spatial distribution of matter in clusters of galaxies is mainly determined by the dominant dark matter component, however, physical processes involving baryonic matter are able to modify it significantly. We analyse a set of 500 pc…
We present observational evidence of the correlation between the high-mass slope of the stellar initial mass function (IMF) in young star clusters and their stellar surface density, $\sigma_{*}$. When the high-mass end of the IMF is…
Accurate specification of a likelihood function is becoming increasingly difficult in many inference problems in astronomy. As sample sizes resulting from astronomical surveys continue to grow, deficiencies in the likelihood function lead…
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…
The angular power spectrum and polarization of the cosmic microwave background radiation (CMB), the relative abundances of primordial hydrogen, deuterium and helium isotopes, and the large-scale structure of the universe all indicate that…
I report the current status on the determinations of the baryon fractions and dynamical/lensing masses of galaxy clusters as well as the $\sigma$ - $T$ relationship, making use of all the published data in literature which include 304…
MOND reduces greatly the mass discrepancy in clusters of galaxies, but does leave a consistent global discrepancy of about a factor of two. It has been proposed, within the minimalist and purist MOND, that clusters harbor some indigenous,…
Two varieties of the universal stellar initial mass function (IMF) viz., the Kroupa and the Chabrier IMF, have emerged over the last decade to explain the observed distribution of stellar masses. The possibility of the universal nature of…
Observations of mergers of multi-compact object systems offer insights to the formation processes of massive stars in globular clusters. Simulations of stellar clusters, may be used to understand and interpret observations. Simulations…
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…
Analyses of strong gravitational lenses, galaxy-scale kinematics, and absorption line stellar population synthesis (SPS) have all concluded that the stellar initial mass function (IMF) varies within the massive early-type galaxy (ETG)…
Recent results suggest that the initial mass function (IMF) of globular clusters (GCs) is metallicity and density dependent. Here it is studied how this variation affects the initial masses and the numbers of core collapse supernovae…
Low mass star formation regions are unlikely to fully populate their initial mass functions, leading to a deficit of massive stars. In binary stellar populations, the full range of binary separations and mass ratios will also be…
We study the origin of iron and alpha-elements (O, Mg, Si) in clusters of galaxies. In particular, we discuss the [O/Fe] ratio and the iron mass-to-luminosity ratio in the intracluster medium (ICM) and their link to the chemical and…
Dark matter is the generally accepted paradigm in astrophysics and cosmology as a solution to the higher rate of rotation in galaxies, among many other reasons. But since there are still some problems encountered by the standard dark matter…
Recent studies of nearby globular clusters have discovered excess dark mass in their cores, apparently in an extended distribution, and simulations indicate that this mass is composed mostly of white dwarfs (respectively stellar-mass black…
AIMS. To derive the mass profiles of the different luminous and dark components in clusters. METHODS. The cluster mass profile is determined by using the Jeans equation applied to the projected phase-space distribution of about 3000…