- ID:
- ivo://CDS.VizieR/J/ApJ/850/207
- Title:
- Action dynamics of the Local Supercluster
- Short Name:
- J/ApJ/850/207
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The fully nonlinear gravitationally induced trajectories of a nearly complete set of galaxies, groups, and clusters in the Local Supercluster are constructed in a numerical action method model constrained by data from the CosmicFlows survey and various distance indicators. We add the gravity field due to inhomogeneities external to the sample sphere by making use of larger-scale peculiar flow measurements. Assignments of total masses were made to find the best overall set of mutual attractions, as determined by a goodness criterion based on present-day radial velocities, individually for the Virgo Cluster, M31, and the Milky Way (MW), and via a mass-to-light ratio relationship for other masses. The low median chi-square found indicates that the model fits the present-day velocity flow well, but a slightly high mean chi-square may indicate that some masses underwent complex orbits. The best fit, when setting the value of H_0_ to the CosmicFlows value of 75km/s/Mpc and the WMAP value for {Omega}_m_=0.244 consistent with that H_0_, occurs with the following parameters: {Omega}_orphan_=0.077+/-0.016, M/L_K_=40+/-2L_10_^0.15^M_{sun}_/L_{sun}_ (L_10_ is the K-band luminosity in units of 10^10^L_{sun}_), a Virgo mass of 6.3+/-0.8x10^14^M_{sun}_ (M/L_K_=113+/-15M_{sun}_/L_{sun}_), and a mass for the MW plus M31 of 5.15+/-0.35x10^12^M_{sun}_. The best constant mass-to-light ratio is M/L_K_=58+/-3M_{sun}_/L_{sun}_. The Virgocentric turnaround radius is 7.3+/-0.3Mpc. We explain several interesting trends in peculiar motions for various regions now that we can construct the 3D orbital histories.
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- ID:
- ivo://CDS.VizieR/J/A+AS/137/369
- Title:
- 10 active binary radial velocities
- Short Name:
- J/A+AS/137/369
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Orbital elements have been determined for 10 chromospherically active binaries from a combination of new velocities and velocities in the literature. First orbits for three binaries, HD 33363, HD 152178, and HD 208472, are presented, as well as updated orbits for seven other binaries. Two of the latter systems, LN Peg and HD 106225 were discovered to be triple, and both short- and long-period orbits have been computed for each. Fundamental properties have been determined for the chromospherically active primary in each system.
- ID:
- ivo://CDS.VizieR/J/A+A/575/A4
- Title:
- Activity and accretion in {gamma} Vel and Cha I
- Short Name:
- J/A+A/575/A4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the fundamental parameters (effective temperature, surface gravity, lithium abundance, and radial velocity) delivered by the GES consortium in the first internal data release to select the members of Gamma Vel and Cha I among the UVES and GIRAFFE spectroscopic observations. A total of 140 Gamma Vel members and 74 Cha I members were studied. The procedure adopted by the GES to derive stellar fundamental parameters provided also measures of the projected rotational velocity (vsini). We calculated stellar luminosities through spectral energy distributions, while stellar masses were derived by comparison with evolutionary tracks. The spectral subtraction of low-activity and slowly rotating templates, which are rotationally broadened to match the vsini of the targets, enabled us to measure the equivalent widths (EWs) and the fluxes in the H{alpha} and H{beta} lines. The H{alpha} line was also used for identifying accreting objects, on the basis of its equivalent width and the width at the 10% of the line peak (10%W), and for evaluating the mass accretion rate (M_acc_). The distribution of vsini for the members of Gamma Vel displays a peak at about 10km/s with a tail toward faster rotators. There is also some indication of a different vsini distribution for the members of its two kinematical populations. Most of these stars have H{alpha} fluxes corresponding to a saturated activity regime. We find a similar distribution, but with a narrower peak, for Cha I. Only a handful of stars in Gamma Vel display signatures of accretion, while many more accretors were detected in the younger Cha I, where the highest H{alpha} fluxes are mostly due to accretion, rather than to chromospheric activity. Accreting and active stars occupy two different regions in a T_eff-flux diagram and we propose a criterion for distinguishing them. We derive M_acc in the ranges 10^-11^-10^-9^M_{sun}_/yr and 10^-10^-10^-7^M_{sun}_/yr for Gamma Vel and Cha I accretors, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/531/A8
- Title:
- Activity indices and velocities for 890 stars
- Short Name:
- J/A+A/531/A8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work we present chromospheric activity indices, kinematics, radial-velocities, and rotational velocities for more than 850 FGK-type dwarfs and subgiant stars in the southern hemisphere and test how best to calibrate and measure S -indices from echelle spectra. We measured our parameters using the high-resolution and high-S/N FEROS echelle spectra acquired for this purpose. Results. We confirm the bimodal distribution of chromospheric activities for such stars and highlight the role that the more active K-dwarfs play in biasing the number of active stars. We show that the age-activity relationship does appear to continue to ages older than the Sun if we simply compare main sequence stars and subgiant stars with an offset of around 2.5Gyr between the peaks of both distributions. Also we show evidence of an increased spin-down timescale for cool K dwarfs compared with earlier F and G type stars. We highlight that activities drawn from low-resolution spectra (R<2.500') significantly increase the rms scatter when calibrating onto common systems of measurements like the Mt. Wilson system. Also we show that older and widely used catalogues of activities in the south appear to be offset compared to more recent works at the ~0.1dex level in logR'HK through calibrator drift. In addition, we show how kinematics can be used to preselect inactive stars for future planet search projects. We see the well known trend between projected rotational velocity and activity, however we also find a correlation between kinematic space velocity and chromospheric activity. It appears that after the Vaughan-Preston gap there is a quick step function in the kinematic space motion towards a significantly broader spread in velocities. We speculate on reasons for this correlation and provide some model scenarios to describe the bimodal activity distribution through magnetic saturation, residual low level gas accretion, or accretion by the star of planets or planetesimals. Finally, we provide a new empirical measurement for the disk-heating law, using the latest age-activity relationships to reconstruct the age-velocity distribution for local disk stars. We find a value of 0.337+/-0.045 for the exponent of this power law, in excellent agreement with those found using isochrone fitting methods and with theoretical disk-heating models.
- ID:
- ivo://CDS.VizieR/J/other/Ap/62.147
- Title:
- Activity types of ROSAT/SDSS galaxies
- Short Name:
- J/other/Ap/62.14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this study we carry out detailed spectral classification of 173 AGN candidates from the Joint HRC/BHRC sample, which is a combination of HRC (Hamburg-ROSAT Catalogue) and BHRC (Byurakan-Hamburg-ROSAT Catalogue). These objects were revealed as optical counterparts for ROSAT X-ray sources, however spectra for 173 of them are given in SDSS without definite spectral classification. We studied these 173 objects using the SDSS spectra and revealed the detailed activity types for them. Three diagnostic diagrams and direct examination of the spectra were used to have more confident classification. We also made identification of these sources in other wavelength ranges and calculated some of their parameters.
- ID:
- ivo://CDS.VizieR/J/PAZh/24/918
- Title:
- ADS 9731: a new sextuple system
- Short Name:
- J/PAZh/24/918
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations with the correlation radial velocity meter of ADS 9731 were carried out during 1996-1997. We established that the components A and D of the visual quadruple system ADS 9731 are spectroscopic binaries with periods of 3.87 and 14.3 days, respectively. Their orbits are computed. New photometry has demonstrated the absence of eclipses in the close pair Aab. The spectral types and luminosities of all six components matching the are found.
- ID:
- ivo://CDS.VizieR/J/A+A/409/245
- Title:
- ADS 11061 radial velocities
- Short Name:
- J/A+A/409/245
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The evolutionary status and origin of the most eccentric known binary in a quadruple system, 41 Dra (e=0.9754, period 3.413yr), are discussed. New observations include the much improved combined speckle-interferometric orbit, resolved photometry of the components and their spectroscopic analysis. The age of the system is 2.5+/-0.2Gyr; all four components are likely coeval. The high eccentricity of the orbit together with known age and masses provide a constraint on the tidal circularization theory: it seems that the eccentric orbit survived because the convective zones of the F-type dwarfs were very thin. Now as the components of 41 Dra are leaving the Main Sequence, their increased interaction at each periastron passage may result in detectable changes in period and eccentricity.
- ID:
- ivo://CDS.VizieR/J/AN/341/645
- Title:
- AE Aur and iota Ori runaway stars RV curves
- Short Name:
- J/AN/341/645
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of our spectroscopic monitoring observations of the late O-type runaway stars AE Aur and iota Ori, carried out between September 2016 and May 2018 using the Echelle spectrograph FLECHAS at the University Observatory Jena. For both stars, we obtained current radial velocity (RV) measurements with better precision than before. These results can be used for further advanced calculations of their space motion, needed to determine, for example, their place of origin in our Galaxy. In this paper, we describe the observations and the data reduction, as well as the analysis of all spectral data. We find a stable RV for AE Aur and confirm iota Ori as a double-lined spectroscopic binary and derive its current Keplerian orbital elements.
- ID:
- ivo://CDS.VizieR/J/A+A/495/15
- Title:
- A959 galaxies r' magnitude and radial velocities
- Short Name:
- J/A+A/495/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The connection of cluster mergers with the presence of extended, diffuse radio sources in galaxy clusters is still being debated. We aim to obtain new insights into the internal dynamics of Abell 959, showing evidence of a diffuse radio source, analyzing velocities and positions of member galaxies. Our analysis is based on redshift data for 107 galaxies in the cluster field acquired at the Telescopio Nazionale Galileo. We also use photometric data from the Sloan Digital Sky Survey (Data Release 6). We combine galaxy velocities and positions to select 81 galaxies recognized as cluster members and determine global dynamical properties. We analyze the cluster searching for substructures by using the weighted gap analysis, the KMM method and the Dressler-Shectman statistics. We also study the 2D galaxy distribution in the field of the cluster. We compare our results with those from X-ray and gravitational lensing analyses.
- ID:
- ivo://CDS.VizieR/J/ApJ/797/124
- Title:
- AGB and RGB stars in 47 Tuc
- Short Name:
- J/ApJ/797/124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the iron abundance of 24 asymptotic giant branch (AGB) stars, members of the globular cluster 47 Tucanae, obtained with high-resolution spectra collected with the FEROS spectrograph at the MPG/ESO 2.2m Telescope. To test the reliability of the chemical analysis, 11 red giant branch (RGB) stars were also studied.
