Metallicities on the Double Main Sequence of ω Centauri Imply Large Helium Enhancement
- G. Piotto, S. Villanova, G. Carraro
- Physics, Geology
- 1 December 2004
Having shown in a recent paper that the main sequence of ω Centauri is split into two distinct branches, we now present spectroscopic results showing that the bluer sequence is less metal-poor. We…
NGC 6791: An Exotic Open Cluster or the Nucleus of a Tidally Disrupted Galaxy?
- G. Carraro, S. Villanova, P. Demarque, M. McSwain, G. Piotto, L. Bedin
- Physics
- 30 December 2005
We report on high-resolution echelle spectroscopy of 20 giant stars in the Galactic old open cluster NGC 6791, obtained with Hydra at the WIYN telescope. High-precision radial velocity allows us to…
EXTRAGALACTIC CHEMICAL ABUNDANCES: DO H ii REGIONS AND YOUNG STARS TELL THE SAME STORY? THE CASE OF THE SPIRAL GALAXY NGC 300
- F. Bresolin, W. Gieren, R. Kudritzki, G. Pietrzyński, M. Urbaneja, G. Carraro
- Physics
- 18 May 2009
We have obtained new spectrophotometric data for 28 H ii regions in the spiral galaxy NGC 300, a member of the nearby Sculptor Group. The detection of several auroral lines, including [O iii] λ4363,…
VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way
- D. Minniti, P. Lucas, M. Zoccali
- Education
- 5 December 2009
Outer structure of the Galactic warp and flare: explaining the Canis Major over-density
Aims. In this paper we derive the structure of the Galactic stellar warp and flare. Methods. We use 2MASS red clump and red giant stars, selected at mean and fixed heliocentric distances of…
KINEMATICS AND CHEMISTRY OF RECENTLY DISCOVERED RETICULUM 2 AND HOROLOGIUM 1 DWARF GALAXIES
- Sergey E. Koposov, A. Casey, N. Ryde
- Physics, Geology
- 29 April 2015
We report on VLT/GIRAFFE spectra of stars in two recently discovered ultra-faint satellites, Reticulum 2 and Horologium 1, obtained as part of the Gaia-ESO Survey. We identify 18 members in Reticulum…
ω Centauri: The Population Puzzle Goes Deeper
- L. Bedin, G. Piotto, G. Carraro
- Physics
- 4 March 2004
We present Hubble Space Telescope observations that show a bifurcation of colors in the middle main sequence of the globular cluster ω Centauri. We see this in three different fields, observed with…
Old open clusters in the outer Galactic disk
- G. Carraro, D. Geisler, S. Villanova, P. Frinchaboy, S. Majewski
- Physics
- 13 September 2007
Context. The outer parts of the Milky Way disk are believed to be one of the main arenas where the accretion of external material in the form of dwarf galaxies and subsequent formation of streams is…
Spectroscopy of QUEST RR Lyrae Variables: The New Virgo Stellar Stream
- S. Duffau, R. Zinn, C. Gallart
- Physics
- 19 October 2005
Eighteen RR Lyrae variables (RRLs) that lie in the "12.ͪ4 clump" identified by the Quasar Equatorial Survey Team (QUEST) have been observed spectroscopically to measure their radial velocities and…
KINEMATICAL AND CHEMICAL VERTICAL STRUCTURE OF THE GALACTIC THICK DISK. II. A LACK OF DARK MATTER IN THE SOLAR NEIGHBORHOOD,
- C. Moni Bidin, G. Carraro, R. Mendez, R. Smith
- Physics
- 17 April 2012
We estimated the dynamical surface mass density Σ at the solar position between Z = 1.5 and 4 kpc from the Galactic plane, as inferred from the kinematics of thick disk stars. The formulation is…
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