Related papers: Using globular clusters to test gravity in the wea…
Most Milky Way globular clusters (GCs) exhibit measurable flattening, even if on a very low level. Both cluster rotation and tidal fields are thought to cause this flattening. Nevertheless, rotation has only been confirmed in a handful of…
An analysis is presented of VLT-FLAMES spectroscopy for three Galactic clusters, NGC3293, NGC4755 and NGC6611. Non-LTE model atmosphere calculations have been used to estimate effective temperatures (from either the helium spectrum or the…
The accelerating expansion of the Universe at recent epochs has called into question the validity of general relativity on cosmological scales. One probe of gravity is a comparison of expansion history of the Universe with the history of…
We have measured the absolute proper motions of four low-latitude, inner-Galaxy globular clusters. These clusters are: NGC 6266 (M62), NGC 6304, NGC 6316 and NGC 6723. The proper motions are on the Hipparcos system, as no background…
We present kinematical analyses of 22 Galactic globular clusters using the Hubble Space Telescope proper motion (HSTPROMO) catalogues recently presented in Bellini et al. (2014). For most clusters, this is the first proper-motion study ever…
We performed spectroscopy of globular clusters associated with NGC 1399 and measured radial velocities of more than 400 clusters, the largest sample ever obtained for dynamical studies. In this progress report, we present the sample and the…
We present a detailed study of the internal kinematics of the Galactic Globular Cluster M 4 (NGC 6121), by deriving the radial velocities from 7250 spectra for 2771 stars distributed from the upper part of the Red Giant Branch down to the…
We analyse a sample of about 2000 galaxies in 40 regular clusters, to look for evidence of segregation with respect to galaxy luminosities and morphological types. We find evidence of luminosity segregation for galaxies brighter than $M_R <…
We report results on the radial velocity dispersion profile built out to the outskirts of NGC 4147, a Milky Way globular cluster with detected strong tidal tails. The cluster was chosen to probe, from an observational point of view, recent…
Detailed studies of resolved young massive star clusters are necessary to determine their dynamical state and evaluate the importance of gas expulsion and early cluster evolution. In an effort to gain insight into the dynamical state of the…
Data are presently available on the luminosities and half-light radii of 101 globular clusters associated with low-luminosity parent galaxies. The luminosity distribution of globulars embedded in dwarf galaxies having $M_{v} > -16$ is found…
Based upon the kinematics of ten globular clusters, it has recently been claimed that the ultra-diffuse galaxy, NCD 1052-DF2, lacks a significant quantity of dark matter. Dynamical analyses have generally assumed that this galaxy is…
Several recent numerical simulations of off-center cluster mergers predict that significant angular momentum with associated velocities of a few x 10^{3} km/s can be imparted to the resulting cluster. Such gas bulk velocities can be…
HIRES on the Keck I telescope has been used to measure the first radial velocities for stars belonging to eleven, heavily-reddened globular clusters in the direction of the inner Galaxy. The question of kinematic substructuring among the…
(abridged) We have measured the absolute proper motions of nine low-latitude, inner Galaxy globular clusters, namely NGC 6273 (M 19), NGC 6284, NGC 6287, NGC 6293, NGC 6333 (M 9), NGC 6342, NGC 6356, NGC 6388 and NGC 6441. These are the…
Within the $\Lambda$CDM cosmology, dark matter haloes are expected to deviate from spherical symmetry. Constraining the halo shapes at large galactocentric distances is challenging due to the low density of luminous tracers. The…
We present results from a wide-field imaging study of the globular cluster (GC) systems of a sample of edge-on, Sb-Sc spiral galaxies ~7-20 Mpc away. This study is part of a larger survey of the ensemble properties of the GC populations of…
What is the role of clusters of galaxies in probing the large-scale velocity field of the universe? We investigate the distribution of peculiar velocities of clusters of galaxies in the popular low-density ($\Omega=0.3$) flat…
NGC 3311 is the central cD galaxy of the Hydra I cluster. We use globular clusters around NGC 3311, combined with kinematical data of the galaxy itself, to investigate the dark matter distribution in the central region of Hydra I. Radial…
Models of $f(R)$ gravity that introduce corrections to the Newtonian potential in the weak field limit are tested at the scale of galaxy clusters. These models can explain the dynamics of spiral and elliptical galaxies without resorting to…