Search Publications
RR Lyrae stars in M31 globular clusters: B514
Clementini, G.; Marconi, M.; Cacciari, C. +8 more
We present preliminary results of a variable star search in the metal-poor globular cluster B514 of the Andromeda galaxy (M31), based on Hubble Space Telescope Wide Field Planetary Camera 2 and Advanced Camera for Surveys observations. A large number of RR Lyrae stars have been identified for the first time in a globular cluster of M31. The averag…
The BSS and binary content of NGC 5024 (M53): a combined LBT/HST study.
Pasian, F.; Fontana, A.; Grazian, A. +27 more
We present deep, wide-field imaging of the Globular Cluster NGC 5024, obtained at the Large Binocular Telescope. Images in U, B and V were obtained with the Large Binocular Camera, allowing to resolve the stars down to U ∼25.5 in a field of view of 25' × 24' . The combination of short and deep exposures allowed the construction of color-magnitude …
Stellar populations in the Local Group starburst galaxy IC10
Giuffrida, G.; Pulone, L.; Sanna, N. +10 more
We present preliminary results of a photometric investigation on IC10 using F555W and F814W data collected with WFPC2@HST covering two different regions. We provide a new estimate of both distance and reddening by adopting the Tip of the Red Giant Branch (TRGB). We find that the RGB stars in the two regions are located at the same distance, but pr…
NGC 2419: an ``intergalactic wanderer'' or a simple Galactic globular cluster? .
Di Criscienzo, M.; Clementini, G.; Ripepi, V. +8 more
We have carried out a new photometric study of the remote Galactic globular cluster NGC 2419, using proprietary and archive B,V,I time-series CCD photometry of the cluster, that allowed us to discover a large number of new variable stars and to obtain a new colour magnitude diagram that reaches V∼ 26 mag over a field of 50x43 square arcmin centere…
Young stellar populations in the Magellanic Clouds .
Vallenari, A.
We discuss the young population of stars and clusters in the Magellanic Clouds. We present the discovery of pre-main sequence candidates in the nebula N 11 in the Large Magellanic Clouds. The comparison of the Colour-Magnitude diagram with pre-main sequence tracks and the presence of Spitzer objects YSO I and II suggest that the star formation has…
Study of the QSO HE0354-5500 with combined HST imaging and VLT spectroscopy . An example of a deconvolution-based method for probing the QSOs host galaxies characteristics
Magain, P.; Courbin, F.; Hutsemékers, D. +2 more
The host galaxy of the QSO HE0354-5500 (M_B=-24.7, z=0.2674) is studied on the basis of high resolution HST optical images and spatially resolved VLT slit spectra. The morphology and dynamics of the host are described. The gas ionization and velocity are mapped as a function of the distance to the central QSO. Reflection or scattering of the QSO H…
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 …
The Black Hole Mass of Abell 1836-BCG and Abell 3565-BCG
Ferrarese, L.; Dalla Bontà, E.; Corsini, E. M. +3 more
Two brightest cluster galaxies (BCGs), namely Abell 1836-BCG and Abell 3565-BCG, were observed with the Advanced Camera for Surveys (ACS) and the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope. By modeling the available photometric and kinematic data, it resulted that the mass of Abell 1836-BCG and Abell 3565-BCG a…