Search Publications

Environmental effects on the globular cluster blue straggler population: a statistical approach .

Moretti, A.; De Angeli, F.; Piotto, G.

Blue stragglers stars (BSS) constitute nowadays an ubiquitous population of objects whose origin involves both dynamical and stellar evolution. In this work we analyze the properties of a catalogue of BSS extracted from an homogeneous sample of 56 Galactic globular clusters observed with WFPC2/HST and described in \citet{pio02}. The goal of this s…

Local Cosmology from Isolated Dwarfs: variable stars from the LCID project.

Monelli, M.; Bernard, E.; LCID Team

During Cycle 14 a total of 113 HST orbits were secured to observe five isolated dwarf galaxies, namely Tucana, LGS3, LeoA, IC1613, and Cetus. The aim of the project is a full characterization of the stellar content of these galaxies, in terms of their SFH, radial distributions, halo populations and variable stars. Deep (V≈29) F475W, F814W data all…

The peculiar horizontal branch morphology of the Galactic globular clusters NGC 6388 and NGC 6441.

Buss, G.

I present multiband optical and UV Hubble Space Telescope photometry of the two Galactic globular clusters NGC 6388 and NGC 6441, in order to investigate the nature of the physical mechanism(s) responsible for the existence of an extended blue tail and of a slope in the horizontal branch. Further evidence that the horizontal branch tilt cannot be …