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16801. Velocities of red giants in the SMC
ID:
ivo://CDS.VizieR/J/MNRAS/442/1663
Title:
Velocities of red giants in the SMC
Short Name:
J/MNRAS/442/1663
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from an extensive spectroscopic survey of field stars in the Small Magellanic Cloud (SMC). 3037 sources, predominantly first-ascent red giants, spread across roughly 37.5deg^2^, are analysed. The line-of-sight velocity field is dominated by the projection of the orbital motion of the SMC around the Large Magellanic Cloud/Milky Way. The residuals are inconsistent with both a non-rotating spheroid and a nearly face on disc system. The current sample and previous stellar and Hi kinematics can be reconciled by rotating disc models with line-of-nodes position angle {Theta} ~120{deg}-130{deg}, moderate inclination (25{deg}-70{deg}), and rotation curves rising at 20-40km/s/kpc. The metal-poor stars exhibit a lower velocity gradient and higher velocity dispersion than the metal-rich stars. If our interpretation of the velocity patterns as bulk rotation is appropriate, then some revision to simulations of the SMC orbit is required since these are generally tuned to the SMC disc line of nodes lying in a north-east-south-west (SW) direction. Residuals show strong spatial structure indicative of non-circular motions that increase in importance with increasing distance from the SMC centre. Kinematic substructure in the north-west part of our survey area is associated with the tidal tail or Counter-Bridge predicted by simulations. Lower line-of-sight velocities towards the Wing and the larger velocities just beyond the SW end of the SMC Bar are probably associated with stellar components of the Magellanic-Bridge and Counter-Bridge, respectively. Our results reinforce the notion that the intermediate-age stellar population of the SMC is subject to substantial stripping by external forces.
16802. Velocities of RFGC galaxies
ID:
ivo://CDS.VizieR/J/other/BSAO/50.5
Title:
Velocities of RFGC galaxies
Short Name:
J/other/BSAO/50.
Date:
21 Oct 2021
Publisher:
CDS
Description:
A list of radial velocities, HI line widths and peculiar velocities of 1327 galaxies from the RFGC catalogue has been compiled using actual observations and literature data. The list can be used for studying bulk motions of galaxies, construction of the field of peculiar velocities and other tasks.
16803. Velocities of RGB stars in the Leo II dwarf galaxy
ID:
ivo://CDS.VizieR/J/AJ/153/254
Title:
Velocities of RGB stars in the Leo II dwarf galaxy
Short Name:
J/AJ/153/254
Date:
21 Oct 2021
Publisher:
CDS
Description:
We combine precision radial velocity data from four different published works of the stars in the Leo II dwarf spheroidal galaxy. This yields a data set that spans 19 years, has 14 different epochs of observation, and contains 372 unique red giant branch stars, 196 of which have repeat observations. Using this multi-epoch data set, we constrain the binary fraction for Leo II. We generate a suite of Monte Carlo simulations that test different binary fractions using Bayesian analysis and determine that the binary fraction for Leo II ranges from 0.30_-0.10_^+0.09^ to 0.34_-0.11_^+0.11^, depending on the distributions of binary orbital parameters assumed. This value is smaller than what has been found for the solar neighborhood (~0.4-0.6) but falls within the wide range of values that have been inferred for other dwarf spheroidals (0.14-0.69). The distribution of orbital periods has the greatest impact on the binary fraction results. If the fraction we find in Leo II is present in low-mass ultra-faints, it can artificially inflate the velocity dispersion of those systems and cause them to appear more dark matter rich than in actuality. For a galaxy with an intrinsic dispersion of 1 km/s and an observational sample of 100 stars, the dispersion can be increased by a factor of 1.5-2 for Leo II-like binary fractions or by a factor of three for binary fractions on the higher end of what has been seen in other dwarf spheroidals.
16804. Velocities of satellites of external disk galaxies
ID:
ivo://CDS.VizieR/J/ApJ/645/228
Title:
Velocities of satellites of external disk galaxies
Short Name:
J/ApJ/645/228
Date:
21 Oct 2021
Publisher:
CDS
Description:
We analyze the angular distribution and the orbital rotation directions of a sample of carefully selected satellite galaxies about disk galaxy primaries extracted from the Sloan Digital Sky Survey (SDSS). We complement this analysis with a theoretical study of these statistics in an N-body simulation of cosmological structure formation set within the {Delta}CDM paradigm under various assumptions for the orientations of disk angular momenta.
16805. Velocities of spiral galaxies in distant clusters
ID:
ivo://CDS.VizieR/J/A+A/422/907
Title:
Velocities of spiral galaxies in distant clusters
Short Name:
J/A+A/422/907
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have conducted an observing campaign with the FORS instruments at the ESO-Very Large Telescope to explore the kinematical properties of spiral galaxies in distant galaxy clusters. Our main goal is to analyse transformation - and interaction processes of disk galaxies within the special environment of clusters as compared to the hierarchical evolution of galaxies in the field. Spatially resolved multi object spectra have been obtained for seven galaxy clusters at 0.3<z<0.6 to measure rotation velocities of cluster members. For three of the clusters, Cl 0303+17, Cl 0413-65, and MS 1008-12, for which we presented results including a Tully-Fisher-diagram in Ziegler et al. (2003ApJ...598L..87Z), we describe here in detail the sample selection, observations, data reduction, and data analysis. Each of them was observed with two setups of the standard MOS-unit of FORS.
16806. Velocities of stars in the Orion Nebula Cluster
ID:
ivo://CDS.VizieR/J/ApJ/676/1109
Title:
Velocities of stars in the Orion Nebula Cluster
Short Name:
J/ApJ/676/1109
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from 1351 high-resolution spectra of 1215 stars in the Orion Nebula Cluster (ONC) and the surrounding Orion 1c association, obtained with the Hectochelle multiobject echelle spectrograph on the 6.5m MMT. We confirmed 1111 stars as members, based on their radial velocity and/or H{alpha} emission. The radial velocity distribution of members shows a dispersion of {sigma}=3.1km/s. We found a substantial north-south velocity gradient and spatially coherent structure in the radial velocity distribution, similar to that seen in the molecular gas in the region. We also identified several binary and high velocity stars, a region exhibiting signs of triggered star formation, and a possible foreground population of stars somewhat older than the ONC.
16807. Velocities of WOCS 24009 and WOCS 40007 in NGC 6819
ID:
ivo://CDS.VizieR/J/AJ/151/66
Title:
Velocities of WOCS 24009 and WOCS 40007 in NGC 6819
Short Name:
J/AJ/151/66
Date:
21 Oct 2021
Publisher:
CDS
Description:
As part of our study of the old (~2.5Gyr) open cluster NGC 6819 in the Kepler field, we present photometric (Kepler and ground-based BVR_C_I_C_) and spectroscopic observations of the detached eclipsing binary WOCS 24009 (Auner 665; KIC5023948) with a short orbital period of 3.6 days. WOCS 24009 is a triple-lined system, and we verify that the brightest star is physically orbiting the eclipsing binary using radial velocities and eclipse timing variations. The eclipsing binary components have masses M_B_=1.090+/-0.010M_{sun}_ and M_C_=1.075+/-0.013M_{sun}_, and radii R_B_=1.099+/-0.006+/-0.005R_{sun}_and R_C_=1.069+/-0.006+/-0.013R_{sun}_. The bright non-eclipsing star resides at the cluster turnoff, and ultimately its mass will directly constrain the turnoff mass: our preliminary determination is M_A_=1.251+/-0.057M_{sun}_. A careful examination of the light curves indicates that the fainter star in the eclipsing binary undergoes a very brief period of total eclipse, which enables us to precisely decompose the light of the three stars and place them in the color-magnitude diagram (CMD). We also present improved analysis of two previously discussed detached eclipsing stars in NGC6819 (WOCS40007 and WOCS23009) en route to a combined determination of the cluster's distance modulus (m-M)_V_=12.38+/-0.04. Because this paper significantly increases the number of measured stars in the cluster, we can better constrain the age of the CMD to be 2.21+/-0.10+/-0.20Gyr. Additionally, using all measured eclipsing binary star masses and radii, we constrain the age to 2.38+/-0.05+/-0.22Gyr. The quoted uncertainties are estimates of measurement and systematic uncertainties (due to model physics differences and metal content), respectively.
16808. Velocities & rotation of CP stars
ID:
ivo://CDS.VizieR/J/A+AS/118/231
Title:
Velocities & rotation of CP stars
Short Name:
J/A+AS/118/231
Date:
21 Oct 2021
Publisher:
CDS
Description:
As part of a systematic project we have determined radial velocities and projected rotational velocities for a sample of 186 chemically peculiar stars which have been observed by the Hipparcos' satellite. The purpose is to provide necessary data to study the space velocities of peculiar stars.
16809. Velocity and distance of methanol maser sources
ID:
ivo://CDS.VizieR/J/other/ChJAA/3.49
Title:
Velocity and distance of methanol maser sources
Short Name:
J/other/ChJAA/3.
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a statistical analysis of 482 6.7GHz methanol maser sources from the available literature, on their maser emission and the characteristics of their associated infrared sources. On the color-color diagram, more than 70% of the objects fall within a very small region (0.57<=[25-12]<=1.30 and 1.30<=[60-12]<=2.50). This suggests that 6.7GHz methanol maser emission occurs only within a very short evolutionary phase during the earliest stage of star formation. The velocity ranges of the masers belong to two main groups: one from 1 to 10km/s, and one from about 11 to 20km/s. These velocity ranges indicate that the masers are probably associated with both disks and outflows. The correlations between the maser and infrared flux densities, and between the maser and infrared luminosities, suggest that far-infrared radiation is a possible pumping mechanism for the masers which most probably originate from some outer molecular envelopes or disks.
16810. Velocity and light curve analysis of three PPNe
ID:
ivo://CDS.VizieR/J/AJ/156/300
Title:
Velocity and light curve analysis of three PPNe
Short Name:
J/AJ/156/300
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have obtained contemporaneous light, color, and radial velocity data for three proto-planetary nebulae (PPNe) over the years 2007 to 2015. The light and velocity curves of each show similar periods of pulsation, with photometric periods of 42 and 50 days for IRAS 17436+5003, 102 days for IRAS 18095+2704, and 35 days for IRAS 19475+3119. The light and velocity curves are complex with multiple periods and small, variable amplitudes. Nevertheless, at least over limited time intervals, we were able to identify dominant periods in the light, color, and velocity curves and compare the phasing of each. The color curves appear to peak with or slightly after the light curves while the radial velocity curves peak about a quarter of a cycle before the light curves. Similar results were found previously for two other PPNe, although for them the light and color appeared to be in phase. Thus, it appears that PPNe are brightest when smallest and hottest. These phase results differ from those found for classical Cepheid variables, where the light and velocity differ by half a cycle, and are hottest at about average size and expanding. However, they do appear to have similar phasing to the larger-amplitude pulsations seen in RV Tauri variables. Presently, few pulsation models exist for PPNe, and these do not fit the observations well, especially the longer periods observed. Model fits to these new light and velocity curves would allow masses to be determined for these post-AGB objects, and thereby provide important constraints to post-AGB stellar evolution models of low- and intermediate-mass stars.

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