8 research outputs found
Searching in the dark: the dark mass content of the Milky Way globular clusters NGC288 and NGC6218
We present an observational estimate of the fraction and distribution of dark
mass in the innermost region of the two Galactic globular clusters NGC 6218
(M12) and NGC 288. Such an assessment has been made by comparing the dynamical
and luminous mass profiles derived from an accurate analysis of the most
extensive spectroscopic and photometric surveys performed on these stellar
systems. We find that non-luminous matter constitutes more than 60% of the
total mass in the region probed by our data (R<1.6 arcmin~r_h) in both
clusters. We have carefully analyzed the effects of binaries and tidal heating
on our estimate and ruled out the possibility that our result is a spurious
consequence of these effects. The dark component appears to be more
concentrated than the most massive stars suggesting that it is likely composed
of dark remnants segregated in the cluster core.Comment: 17 pages, 10 figures, accepted for publication by MNRA
Deep Subaru Hyper Suprime-Cam Observations of Milky Way Satellites Columba I and Triangulum II
A MODEST review
We present an account of the state of the art in the fields explored by the
research community invested in 'Modeling and Observing DEnse STellar systems'.
For this purpose, we take as a basis the activities of the MODEST-17
conference, which was held at Charles University, Prague, in September 2017.
Reviewed topics include recent advances in fundamental stellar dynamics,
numerical methods for the solution of the gravitational N-body problem,
formation and evolution of young and old star clusters and galactic nuclei,
their elusive stellar populations, planetary systems, and exotic compact
objects, with timely attention to black holes of different classes of mass and
their role as sources of gravitational waves.
Such a breadth of topics reflects the growing role played by collisional
stellar dynamics in numerous areas of modern astrophysics. Indeed, in the next
decade, many revolutionary instruments will enable the derivation of positions
and velocities of individual stars in the Milky Way and its satellites and will
detect signals from a range of astrophysical sources in different portions of
the electromagnetic and gravitational spectrum, with an unprecedented
sensitivity. On the one hand, this wealth of data will allow us to address a
number of long-standing open questions in star cluster studies; on the other
hand, many unexpected properties of these systems will come to light,
stimulating further progress of our understanding of their formation and
evolution.Comment: 42 pages; accepted for publication in 'Computational Astrophysics and
Cosmology'. We are much grateful to the organisers of the MODEST-17
conference (Charles University, Prague, September 2017). We acknowledge the
input provided by all MODEST-17 participants, and, more generally, by the
members of the MODEST communit