In recent years, theoretical models of dense stellar systems have
become increasingly sophisticated. It is now possible to develop
realistic N-body models with up to many tens of thousands of stars;
the evolution of binaries and single stars in dense environments can
be followed as the cluster evolves as a whole and all of the models
can be tested extensively against the observations.
On the observational side, the advent of space telescopes and ground-based 10-m size telescopes has provided a huge amount of data, spanning the range of wavelengths from radio to X-rays. The development of astrometrical techniques, and the availability of multifiber high resolution spectrographs allows astrometry and observational kinematics, with radial velocities and proper motions, both from the ground and with HST, measured for up to 10,000 stars per cluster. Large-field imaging cameras now routinely provide photometric data for up to a few hundred thousands stars per cluster. HST and interferometric techniques provide a deep view in the very center of dense stellar systems. A complete inventory of kinematic and photometric properties, from X-ray to near-infrared, of all luminous stars from the very center to the outskirts of clusters and nearby galaxies is now a reality. And an increasing number of catalogs of kinematic and photometric data are now available on the Web. There is a significant progress in the determination of geometrical distances to globular clusters, which will provide a solid foundation for the calibration of their ages and an important step in the distance ladder, both with a significant impact in cosmology. And finally, there has been a great deal of progress in the understanding of extragalactic globular cluster systems, with a complex variety of luminosities, masses, ages, metallicities, and dynamical evolution, and their role in galaxy formation.
It is now time to directly compare the output of the models with the
observation, and MODEST is the ideal framework to do it. This working
group is intended to collect the most up-to-date observational data,
to help develop observational projects to provide input parameters,
and to test the more and more realistic models developed within
MODEST.
| WG home page: | WG9 |
| Contact: | Giampaolo Piotto |