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- ID:
- ivo://CDS.VizieR/J/AJ/115/168
- Title:
- Kinematics of red giant and RR Lyrae stars
- Short Name:
- J/AJ/115/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The kinematics of 122 red giant and 124 RR Lyrae stars in the solar neighborhood are studied using accurate measurements of their proper motions obtained by the Hipparcos astrometry satellite, combined with their published photometric distances, metal abundances, and radial velocities. A majority of these sample stars have metal abundances of [Fe/H]<=-1 and thus represent the old stellar populations in the Galaxy. The halo component, with [Fe/H]<=-1.6, is characterized by a lack of systemic rotation [(<U>, <V>, <W>)=(16+/-18, -217+/-21, -10+/-12)km/s] and a radially elongated velocity ellipsoid [(<U>, <V>, <W>)=(161+/-10, 115+/-7, 108+/-7)km/s]. About 16% of such metal-poor stars have low orbital eccentricities (e<0.4), and we see no evidence of a correlation between [Fe/H] and e. Based on the model for the e-distribution of orbits, we show that this fraction of low-e stars for [Fe/H]<=-1.6 is explained by the halo component alone, without introducing the extra disk component claimed by recent workers. This is also supported by the absence of a significant change in the e-distribution with height from the Galactic plane. In the intermediate-metallicity range (-1.6<[Fe/H]<=-1), we find that stars with disklike kinematics have only modest effects on the distributions of rotational velocities and e for the sample at |z|<1kpc. This disk component appears to constitute only 10% for -1.6<[Fe/H]<=-1 and 20% for -1.4<[Fe/H]<=-1. It is also verified that this metal-weak disk has a mean rotation of ~195km/s and a vertical extent of 1 kpc, which is consistent with the thick disk's dominating at [Fe/H]=-0.6 to -1. We find no metallicity gradient in the halo, whereas there is an indication of a metallicity gradient in the metal-weak tail of the thick disk. The implications of these results for the early evolution of the Galaxy are also presented.
- ID:
- ivo://CDS.VizieR/J/MNRAS/375/1381
- Title:
- Kinematics of RR Lyr and HB stars in NGP
- Short Name:
- J/MNRAS/375/1381
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radial velocities and proper motions (derived from the GSC-II data base) are given for 38 RR Lyrae (RRL) stars and 79 blue horizontal branch (BHB) stars in a ~200deg^2^ area around the North Galactic Pole (NGP). Both heliocentric (UVW) and galactocentric (VR, Vphi, Vz) space motions are derived for these stars using a homogeneous distance scale consistent with (m-M)0=18.52 for the Large Magellanic Cloud (LMC).
- ID:
- ivo://CDS.VizieR/J/PAZh/33/643
- Title:
- Kinematics of Sco-Cen OB Association
- Short Name:
- J/PAZh/33/643
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A fine structure related to the kinematic peculiarities of three components of the Scorpius-Centaurus association (LCC = Lower Centaurus-Crux, UCL = Upper Centaurus-Lupus, and US = Upper Scorpius) has been revealed in the UV-velocity distribution of Gould Belt stars. We have been able to identify the most likely members of these groups by applying the method of analyzing the two-dimensional probability density function of stellar UV velocities that we developed. A kinematic analysis of the identified structural components has shown that, in general, the center-of-mass motion of the LCC, UCL, and US groups follows the motion characteristic of the Gould Belt, notably its expansion. The entire Scorpius-Centaurus complex is shown to possess a proper expansion with an angular velocity parameter of 46+/-8km/s/kpc for the kinematic center with l_0_=-40{deg} and R_0_=110pc found. Based on this velocity, we have estimated the characteristic expansion time of the complex to be 21+/-4Myr. The proper rotation velocity of the Scorpius-Centaurus complex is lower in magnitude, is determined less reliably, and depends markedly on the data quality.
- ID:
- ivo://CDS.VizieR/J/A+AS/122/507
- Title:
- Kinematics of SMC carbon stars
- Short Name:
- J/A+AS/122/507
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a radial velocity survey of a sample of the field population of carbon stars in the outer parts of the Small Magellanic Cloud (SMC). This first set of results includes radial velocities for 71 carbon stars, with an individual precision of +/-2-5km/s. The mean heliocentric velocity of the stars (excluding one very high velocity star) is 149.3+/-3.0km/s with a velocity dispersion of 25.2+/-2.1km/s. These values drop to 145.5+/-2.7km/s and 20.6+/-1.9km/s respectively, if we exclude the stars belonging to the Outer Wing. The velocity distribution does not show the multiple peaks seen in some samples of Population I objects. The mass of the SMC as inferred from the above velocity dispersion (without the outer Wing stars) is =~1.2x10^9^M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/A+A/563/A94
- Title:
- Kinematics of the Gamma Vel cluster
- Short Name:
- J/A+A/563/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A key science goal of the Gaia-ESO survey (GES) at the VLT is to use the kinematics of low-mass stars in young clusters and star forming regions to probe their dynamical histories and how they populate the field as they become unbound. The clustering of low-mass stars around the massive Wolf-Rayet binary system {gamma}^2^ Velorum was one of the first GES targets. Targets were selected from colour-magnitude diagrams and intermediate resolution spectroscopy was used to derive radial velocities and assess membership from the strength of the LiI 6708{AA} line. The radial velocity distribution was analysed using a maximum likelihood technique that accounts for unresolved binaries.
- ID:
- ivo://CDS.VizieR/J/A+A/599/A104
- Title:
- Kinematics of the Local Universe. XVI.
- Short Name:
- J/A+A/599/A104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents 828 new 21-cm neutral hydrogen line measurements carried out with the FORT receiver of the meridian transit Nancay radio telescope (NRT) in the years 2000-2007. This observational program was part of a larger project aiming at collecting an exhaustive and magnitude-complete HI extragalactic catalog for Tully-Fisher applications. Through five massive data releases, the KLUN series has collected an homogeneous sample of 4876 HI-spectra of spiral galaxies, complete down to a flux of 5Jy.km/s and with declination {delta}>-40^{deg}. We publish here the last release of the KLUN HI observational program, corresponding to the faint end of the survey, with HI masses ranging from 5x10^8^ to 5x10^10^ solar masses. The size of this final sample is comparable to the catalogs based on the Arecibo and Parkes radio telescope campaigns, and it allows general HI-mass distribution studies from a set of homogeneous radio measurements.
- ID:
- ivo://CDS.VizieR/J/AJ/110/463
- Title:
- Kinematics of the Shapley supercluster
- Short Name:
- J/AJ/110/463
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new analysis of the kinematics of the Shapley supercluster based on radial velocities for 1087 galaxies in the clusters A3558 (Shapley 8), A3528 (Klemola 21), A3532 (Klemola 22), A3530, A3556 (SC 1321-314), A3559 (CE 1327-292), A3560, A3562, SC 1329-314 and in the intercluster region of the core of the supercluster, of which 367 are new measurements. We also present accurate positions from APM and MAMA scans of the ESO/SERC Southern Sky Survey photographic plates. We obtain new velocity dispersions and estimate the masses of the member clusters, evaluating dynamical models of the supercluster. The supercluster is found to be significantly flattened. We find that for Omega_0=0.3, H_0=75km/s/Mpc, the gravitational pull of the supercluster may account for up to 25% of the peculiar velocity of the Local Group required to explain the dipole anisotropy of the Cosmic Microwave Background radiation, in which case the mass of the supercluster would be dominated by intercluster dark matter. This fractional contribution would be considerably higher for combinations of significantly lower values of Omega_0 and higher values of H_0.
- ID:
- ivo://CDS.VizieR/J/MNRAS/357/497
- Title:
- Kinematics of W UMa-type binaries
- Short Name:
- J/MNRAS/357/497
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The kinematics of 129 W Ursae Majoris type binaries (W UMas) were studied. The sample is heterogeneous with different orbits and physically different components from F to K spectral-type main-sequence stars. The computed U, V, W space velocities indicate that the sample is also heterogeneous in velocity space.
- ID:
- ivo://CDS.VizieR/J/MNRAS/402/2369
- Title:
- Kinematics of young associations/clusters
- Short Name:
- J/MNRAS/402/2369
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Young isolated radio-quiet neutron stars are still hot enough to be detectable at X-ray and optical wavelengths due to their thermal emission and can hence probe cooling curves. An identification of their birth sites can constrain their age. For that reason, we try to identify the parent associations for four of the so-called Magnificent Seven neutron stars for which proper motion and distance estimates are available. We are tracing back in time each neutron star and possible birth association centre to find close encounters. The associated time of the encounter expresses the kinematic age of the neutron star which can be compared to its characteristic spin-down age. Owing to observational uncertainties in the input data, we use Monte Carlo simulations and evaluate the outcome of our calculations statistically. RX J1856.5-3754 most probably originated from the Upper Scorpius association about 0.3Myr ago. RX J0720.4-3125 was either born in the young local association TW Hydrae about 0.4Myr ago or in Trumpler 10 0.5Myr in the past. Also RX J1605.3+3249 and RBS 1223 seem to come from a nearby young association such as the Scorpius-Centraurus complex or the extended Corona-Australis association. For RBS 1223 also a birth in Scutum OB2 is possible. We also give constraints on the observables as well as on the radial velocity of the neutron star. Given the birth association, its age and the flight time of the neutron star, we estimate the mass of the progenitor star. Some of the potential supernovae were located very nearby (<100pc) and thus should have contributed to the 10Be and 60Fe material found in the Earth's crust. In addition, we reinvestigate the previously suggested neutron star/runaway pair PSR B1929+10/zeta Ophiuchi and conclude that it is very likely that both objects were ejected during the same supernova event.