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.
These tables give the mean radial velocities for 591 stars in the vicinity of the globular cluster M15 (NGC 7078). 230 of these are members of the cluster, the remaining 361 are most likely non-members, although the membership, or otherwise, of the faintest stars with velocities near that of the cluster was impossible to determine. The radial velocities were measured using the Hydra multi-object spectrograph on the WIYN telescope. For cluster members, the median uncertainty is 0.3 km/s.
A detailed dynamical analysis of the nearby rich Norma cluster (ACO 3627) is presented. From radial velocities of 296 cluster members, we find a mean velocity of 4871+/-54km/s and a velocity dispersion of 925km/s. The mean velocity of the E/S0 population (4979+/-85km/s) is offset with respect to that of the S/Irr population (4812+/-70km/s) by {Delta}v=164km/s in the cluster rest frame. This offset increases towards the core of the cluster. The E/S0 population is free of any detectable substructure and appears relaxed. Its shape is clearly elongated with a position angle that is aligned along the dominant large-scale structures in this region, the so-called Norma wall. The central cD galaxy has a very large peculiar velocity of 561km/s which is most probably related to an ongoing merger at the core of the cluster.
Globular clusters are useful for testing the validity of Newtonian dynamics in the low acceleration regime typical of galaxies, without the complications of non-baryonic dark matter. In the absence of disturbing effects, such as tidal heating, the velocity dispersion of globular clusters is expected to vanish at large radii. If this is not observed, and in particular if, as observed in elliptical galaxies, the dispersion is found to be constant at large radii below a certain threshold acceleration, this might indicate a breakdown of Newtonian dynamics. To minimize the effects of tidal heating that can increase the velocity dispersion at large radii, we study the velocity dispersion profile of two distant globular clusters, NGC 1851 and NGC 1904. The velocity dispersion profile is derived from accurate radial velocity measurements, obtained at the ESO 8m VLT telescope with the FLAMES multi-object spectrograph. Reliable data for 184 and 146 bona fide cluster star members were obtained for NGC 1851 and NGC 1904, respectively.
We present a new insight on NGC 6034 and UGC 842, two groups of galaxies previously reported in the literature as being fossil groups. The study is based on optical photometry and spectroscopy obtained with the CTIO Blanco telescope and Sloan Digital Sky Survey archival data.
Radial velocities have been determined for a sample of 2930 B2-F5 stars, 95% observed by the Hipparcos satellite in the north hemisphere and 80% without reliable radial velocity up to now. Observations were obtained at the Observatoire de Haute Provence with a dispersion of 80{AA}/mm with the aim of studying stellar and galactic dynamics. Radial velocities have been measured by correlation with templates of the same spectral class. The mean obtained precision is 3.0km/s with three observations. A new MK spectral classification is estimated for all stars.
Radial velocities & light curves for HATS-43-HATS-46
Short Name:
J/AJ/155/112
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of four short-period extrasolar planets transiting moderately bright stars from photometric measurements of the HATSouth network coupled to additional spectroscopic and photometric follow-up observations. While the planet masses range from 0.26 to 0.90 M_J_, the radii are all approximately a Jupiter radii, resulting in a wide range of bulk densities. The orbital period of the planets ranges from 2.7 days to 4.7 days, with HATS-43b having an orbit that appears to be marginally non-circular (e=0.173+/-0.089). HATS-44 is notable for having a high metallicity ([Fe/H]=0.320+/-0.071). The host stars spectral types range from late F to early K, and all of them are moderately bright (13.3<V<14.4), allowing the execution of future detailed follow-up observations. HATS-43b and HATS-46b, with expected transmission signals of 2350 ppm and 1500 ppm, respectively, are particularly well suited targets for atmospheric characterization via transmission spectroscopy.
The radial velocities measured on plates taken with Small Objective Prism instrument at Observatoire de Haute-Provence (OHP), and published in the years 1955-1968, have been improved; the radial velocities derived from a single plate measurement have been eliminated. These corrections imply modifications in Evans's catalogue <III/47>; the modifications have been reported in the "WEB" catalogue <III/190> (see Duflot et al., =1995A&AS..114..269D)