The multi-object fiber-fed spectrograph AAOmega at the Anglo-Australian Telescope has been used to establish and measure accurate (<=1km/s) radial velocities for a new sample of members in the outer parts of the stellar system {omega} Centauri. The new sample more than doubles the number of known members with precise velocities that lie between 25' and 45' from the cluster center. Combining this sample with earlier work confirms that the line-of-sight velocity dispersion of {omega} Cen remains approximately constant at ~6.5km/s in the outer parts of the cluster, which contain only a small fraction of the total cluster stellar mass. It is argued that the approximately constant velocity dispersion in the outer regions is most likely a consequence of external influences, such as the tidal shock heating that occurs each time {omega} Cen crosses the Galactic plane. There is therefore no requirement to invoke dark matter or non-standard gravitational theories.
List of 1966 radial velocity measurements of stars in globular cluster Omega Centauri (NGC 5139) taken with the ARGUS multi-object spectrometer at the CTIO 4m Blanco telescope. All the stars have a B magnitude brighter than 16.5. The median error is less than 2km/s. The stars are numbered using their LID (Leiden Identification Number) from van Leeuwen et.al. (2000, Cat. <J/A+A/360/472>). In a companion paper by van de Ven et al. (2006A&A...445..513V), we correct these radial velocities for the perspective rotation caused by the space motion of the cluster. Additionaly 339 stars where measured. These consist of (i) 87 stars with B-V<0.4, (ii) 252 stars not in the van Leeuwen et al. catalog. We suspect that that many of these stars have an erroneous value for their radial velocity.
This second part of the bibliography contains 6504 individual radial velocities for 774 stars in 78 open clusters. It is devoted to NGC and IC open clusters. The first part (Mermilliod J.-C., 1979, Bull. Inform. CDS 16,2; catalogue III/55/) contains the data for five nearby open clusters. The collected data have been found in the literature published from 1900 to the end of 1983. This catalog contains also unpublished data which have been delivered to Mermilliod by several authors.
We present accurate radial velocities and photoelectric UBV photometry for 73 and 57 red-giant candidates, respectively, in the intermediate-age open clusters NGC 2324, 2818, 3960 and 6259. These data confirm the membership of 47 stars, 12 of which (26% ) are spectroscopic binaries; three preliminary orbits have been determined in NGC 3960. From Washington photometry of 8 red giant members, the metallicity of NGC 6259 is found to be [Fe/H]=0.06+/-0.08. At the age of these clusters, most of the red giants are observed in the core-helium (clump) burning phase, the general morphology of which is well reproduced by theoretical models with convective overshooting. However, a number of bona fide cluster giant members are found significantly to the red of the isochrones fitting the rest of the CMD of these and a few other clusters. Some of these stars are binaries, but others seem to be single. In either case, their red colours and/or low luminosities remain unexplained by current stellar evolution theory.
We obtained precise line-of-sight radial velocities of 23 member stars of the remote halo globular cluster Palomar 4 (Pal 4) using the High Resolution Echelle Spectrograph at the Keck I telescope. We also measured the mass function of the cluster down to a limiting magnitude of V~28mag using archival Hubble Space Telescope/Wide Field Planetary Camera 2 (WFPC2) imaging. We derived the cluster's surface brightness profile based on the WFPC2 data and on broad-band imaging with the Low Resolution Imaging Spectrometer at the Keck II telescope.
Heliocentric radial velocities accurate to <~50km/s are given for 1267 galaxies in the fields of 14 rich clusters from the Dressler (1980, Cat. <VII/174>) catalog (instead of 1268 velocities in 15 clusters as indicated in the title).
The Gaia-ESO survey is a large public spectroscopic survey aimed at investigating the origin and formation history of our Galaxy by collecting spectroscopy of representative samples (about 10^5^ Milky Way stars) of all Galactic stellar populations, in the field and in clusters.The survey uses globular clusters as intra- and inter-survey calibrators, deriving stellar atmospheric parameters and abundances of a significant number of stars in clusters, along with radial velocity determinations. We used precise radial velocities of a large number of stars in seven globular clusters (NGC 1851, NGC 2808, NGC 4372, NGC 4833, NGC 5927, NGC 6752, and NGC 7078) to validate pipeline results and to preliminarily investigate the cluster internal kinematics. Radial velocity measurements were extracted from FLAMES/GIRAFFE spectra processed by the survey pipeline as part of the second internal data release of data products to ESO. We complemented our sample with ESO archival data obtained with different instrument configurations. Reliable radial velocity measurements for 1513 bona fide cluster star members were obtained in total. We measured systemic rotation, estimated central velocity dispersions, and present velocity dispersion profiles of all the selected clusters, providing the first velocity dispersion curve and the first estimate of the central velocity dispersion for the cluster NGC 5927. Finally, we explore the possible link between cluster kinematics and other physical parameters. The analysis we present here demonstrates that Gaia-ESO survey data are sufficiently accurate to be used in studies of kinematics of stellar systems and stellar populations in the Milky Way.
Radial velocities are presented for 430 stars in the U direction (l=0,b=0), 445 stars in the V direction (l=90,b=0) and 420 stars in the W direction (b=90). The stars were chosen from the SAO catalog to be within about 10deg of the respective cardinal directions, to be brighter than m(pg) about 10.5mag, and between spectral classes A5 and K0. Except for the K0 stars, almost all are dwarfs. They were chosen to present a kinematically unbiased selection, as the intent was to understand the percentage of stars in each kinematic component of the galaxy.
We present the results of time-resolved spectroscopy of 13 O-type stars in the Cas OB6 stellar association. We conducted a survey for radial velocity variability in search of binary systems, which are expected to be plentiful in young OB associations.
