Related papers: Do globular clusters possess Dark Matter halos? A …
The origin and formation of globular clusters has remained a mystery. We present a formation scenario for ancient globular cluster-like objects that form in ultra-high resolution simulations (smallest cell size $<0.1\,\mathrm{pc}$, mass…
We present theoretical constraints for the formation of the newly discovered dark star clusters (DSCs) with high mass-to-light (M/L) ratios, from Taylor et al (2015). These compact stellar systems photometrically resemble globular clusters…
We explore the cosmological halo-to-halo scatter of the distribution of mass within dark matter halos utilizing a well-resolved statistical sample of clusters from the cosmological Millennium simulation. We find that at any radius, the…
Recent Strong lensing data and rotation curves of dwarf galaxies indicate that many galactic clusters may have a soft core instead of a central cusp in their density distribution. This result challenges the standard CDM (Cold Dark Matter)…
A large number of studies have found that the dark matter surface density, given by the product of the dark matter core radius ($r_c$) and core density ($\rho_c$) is approximately constant for a wide range of galaxy systems. However, there…
We report on the results from an ongoing program aimed at testing Newton's law of gravity in the low acceleration regime using globular clusters. It is shown that all clusters studied so far do behave like galaxies, that is, their velocity…
Recent observations revealed a mysterious ultra diffuse galaxy, NGC1052-DF2, in the group of a large elliptical galaxy, NGC1052. Compared to expectations from abundance matching models, the dark matter mass contained in NGC1052-DF2 is…
I discuss measurements of disk mass from non-circular streaming motions of gas in the barred galaxies NGC 3095 and NGC 4123. In these galaxies with strong shocks and non-circular motions, the inner regions must be disk-dominated to…
I use $N$-body simulations to investigate the morphology and the dynamical evolution and properties of dark matter halos in clusters of galaxies. My sample consists of nine massive halos, coming from an Einstein-de Sitter universe with…
In two recent papers, we developed a powerful technique to link the distribution of galaxies to that of dark matter haloes by considering halo occupation numbers as function of galaxy luminosity and type. In this paper we use these…
The dark matter content of the ultra diffuse galaxy NGC1052-DF2, as inferred from globular cluster (GC) and stellar kinematics, carries a considerable amount of uncertainty, with current constraints also allowing for the complete absence of…
We have used HST and ground-based photometry to determine total $V$-band magnitudes and mass-to-light ratios of more than 150 Galactic globular clusters. We do this by summing up the magnitudes of their individual member stars, using…
To further test MOdified Newtonian Dynamics (MOND) on galactic scales -- originally proposed to explain the rotation curves of disk galaxies without dark matter -- we study a sample of six strong gravitational lensing early-type galaxies…
We use a hybrid approach that combines high-resolution simulations of the formation of a Milky Way-like halo with a semi-analytic model of galaxy formation to study the mass content of dwarf galaxies in the concordance $\Lambda$CDM…
We exclude hydrogen burning stars, of any mass above the hydrogen-burning limit and any metallicity, as significant contributors to the massive halos deduced from rotation curves to dominate the outer parts of spiral galaxies. We present…
It has been shown by Paczy\'nski that gravitational microlensing is potentially a useful method for detecting the dark constituents of the halo of our galaxy, if their mass lies in the approximate domain $10^{-6} < M/M_{\odot} < 10^{-1}$.…
According to the now strongly supported concordance $\Lambda$CDM model, galaxies may be grossly described as a luminous component embedded in a dark matter halo. The density profile of these mass dominating haloes may be determined by N -…
We present a detailed analysis of the kinematics of the Galactic globular cluster NGC 6397 based on more than ~18,000 spectra obtained with the novel integral field spectrograph MUSE. While NGC 6397 is often considered a core collapse…
We present a second set of results from a wide-field photometric survey of the environs of Milky Way globular clusters. The clusters studied are NGC 1261, NGC 1851 and NGC 5824: all have data from DECam on the Blanco 4m telescope. NGC 5824…
Despite the Milky Way's proximity to us, our knowledge of its dark matter halo is fairly limited, and there is still considerable uncertainty in its halo mass. Many past techniques have been limited by assumptions such as the Galaxy being…