The globular cluster HP1 is projected on the bulge, very close to the Galactic center. The Multi-Conjugate Adaptive Optics (MCAO) Demonstrator (MAD) at the Very Large Telescope (VLT) allowed to acquire high resolution deep images that, combined with
first epoch New Technology Telescope (NTT) data, enabled to derive accurate proper motions. The cluster and bulge field stellar contents were disentangled by means of this process, and produced unprecedented definition in the color-magnitude diagrams for this cluster. The metallicity of [Fe/H] ~ -1.0 from previous spectroscopic analysis is confirmed, which together with an extended blue horizontal branch, imply an age older than the halo average. Orbit reconstruction results suggest that HP1 is spatially confined within the bulge.
The Antennae galaxies are the closest example of an ongoing major galaxy merger, and thereby represent a unique laboratory for furthering the understanding of the formation of exotic objects (e.g., tidal dwarf galaxies, ultra-luminous X-ray sources,
super-stellar clusters, etc). In a previous paper HST/WFPC2 observations were used to demonstrate that the Antennae system might be at a distance considerably less than that conventionally assumed in the literature. Here we report new, much deeper HST/ACS imaging that resolves the composite stellar populations, and most importantly, reveals a well-defined red giant branch. The tip of this red giant branch (TRGB) is unambiguously detected at Io(TRGB)=26.65 +/- 0.09 mag. Adopting the most recent calibration of the luminosity of the TRGB then yields a distance modulus for the Antennae of (m-M)o= 30.62 +/- 0.17 corresponding to a distance of 13.3 +/- 1.0 Mpc. This is consistent with our earlier result, once the different calibrations for the standard candle are considered. We briefly discuss the implications of this now well determined shorter distance.
