Search

Start Over Capability Type Simple Cone Search
16771. Velocities of Cygnus OB2 massive binaries
ID:
ivo://CDS.VizieR/J/ApJS/213/34
Title:
Velocities of Cygnus OB2 massive binaries
Short Name:
J/ApJS/213/34
Date:
21 Oct 2021
Publisher:
CDS
Description:
We analyze orbital solutions for 48 massive multiple-star systems in the Cygnus OB2 association, 23 of which are newly presented here, to find that the observed distribution of orbital periods is approximately uniform in log P for P<45days, but it is not scale-free. Inflections in the cumulative distribution near 6days, 14days, and 45days suggest key physical scales of =~0.2, =~0.4, and =~1A.U. where yet-to-be-identified phenomena create distinct features. No single power law provides a statistically compelling prescription, but if features are ignored, a power law with exponent {beta}=~-0.22 provides a crude approximation over P=1.4-2000days, as does a piece-wise linear function with a break near 45days. The cumulative period distribution flattens at P>45days, even after correction for completeness, indicating either a lower binary fraction or a shift toward low-mass companions. A high degree of similarity (91% likelihood) between the Cyg OB2 period distribution and that of other surveys suggests that the binary properties at P<~25days are determined by local physics of disk/clump fragmentation and are relatively insensitive to environmental and evolutionary factors. Fully 30% of the unbiased parent sample is a binary with period P<45days. Completeness corrections imply a binary fraction near 55% for P<5000days. The observed distribution of mass ratios 0.2<q<1 is consistent with uniform, while the observed distribution of eccentricities 0.1<e<0.6 is consistent with uniform plus an excess of e=~0 systems. We identify six stars, all supergiants, that exhibit aperiodic velocity variations of ~30km/s attributed to atmospheric fluctuations.
16772. Velocities of F-G-K stars in Blanco 1
ID:
ivo://CDS.VizieR/J/A+A/485/95
Title:
Velocities of F-G-K stars in Blanco 1
Short Name:
J/A+A/485/95
Date:
21 Oct 2021
Publisher:
CDS
Description:
The nearby open cluster Blanco 1 is of considerable astrophysical interest for formation and evolution studies of open clusters because it is the third highest Galactic latitude cluster known. It has been observed often, but so far no definitive and comprehensive membership determination is readily available. An observing programme was carried out to study the stellar population of Blanco 1, and especially the membership and binary frequency of the F5-K0 dwarfs. We obtained radial-velocities with the CORAVEL spectrograph in the field of Blanco 1 for a sample of 148 F-G-K candidate stars in the magnitude range 10<V<14. New proper motions and UBVI CCD photometric data from two extensive surveys were obtained independently and are used to establish reliable cluster membership assignments in concert with radial-velocity data. The membership of 68 stars is confirmed on the basis of proper motion, radial velocity, and photometric criteria. Fourteen spectroscopic- and suspected binaries (2 SB2s, 9 SB1s, 3SB?) have been discovered among the confirmed members. Thirteen additional stars are located above the main sequence or close to the binary ridge, with radial velocities and proper motions supporting their membership. These are probable binaries with wide separations. Nine binaries (7 SB1 and 2 SB2) were detected among the field stars. The spectroscopic binary frequency among members is 20% (14/68); however, the overall binary rate reaches 40% (27/68) if one includes the photometric binaries. The cluster mean heliocentric radial velocity is +5.53+/-0.11km/s based on the most reliable 49 members. The Vsini distribution is similar to that of the Pleiades, confirming the age similarities between the two clusters.
16773. Velocities of 1253 F-K dwarfs in open clusters
ID:
ivo://CDS.VizieR/J/A+A/498/949
Title:
Velocities of 1253 F-K dwarfs in open clusters
Short Name:
J/A+A/498/949
Date:
21 Oct 2021
Publisher:
CDS
Description:
A long-term monitoring of solar-type dwarfs in 13 nearby open clusters, d<500pc, was conducted during 19 years, but most individual radial velocities were not published, with the exception of a small number of spectroscopic binaries. The program was designed to study the membership, the duplicity, and to search for new members. We obtained 6070 radial velocities during 19 years at the Haute-Provence Observatory (France) and 1130 during 13 years at ESO La Silla (Chile) for 1253 stars in the field of 13 open clusters. The zero point of the CORAVEL radial velocity system has been improved and the new values supersede those published previously. The membership and binarity of solar-type stars in NGC 1976 (Orion), IC 2602, NGC 7092, and NGC 2682 are briefly discussed. For the whole sample, we confirm the membership of 894 stars and discovered 150 new spectroscopic binaries among them. Added to those already known in the Hyades and Coma Berenices, the number of member spectroscopic binaries amounts to 188. The overall binary frequency is 30% (188/618) for stars with at least 2 measurements. IC 2602 may represent an exception because no spectroscopic binaries were found among the 26 members. New orbital elements were computed with the updated values of the radial velocities for 66 systems, representing 55 members and 11 non-members. This paper is the last one from our team reporting CORAVEL radial velocities of solar-type dwarfs in nearby open clusters. All CORAVEL observations for dwarfs and red giants in open clusters are now available in electronic form.
16774. Velocities of 12 Fornax elliptical galaxies
ID:
ivo://CDS.VizieR/J/A+AS/133/325
Title:
Velocities of 12 Fornax elliptical galaxies
Short Name:
J/A+AS/133/325
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present extended stellar kinematics for a sample of elliptical galaxies in the Fornax cluster. Out of the 13 galaxies presented here, five (FCC 119, FCC 136, NGC 1373, NGC 1428, FCC 335) have no previously published kinematical data. Major-axis velocity dispersion profiles (VDPs) and rotation curves (RCs) are given for 12 of the galaxies. A major feature of this data is the spatial extension: for 8 galaxies the data extends beyond 1R_e_, and for 5 it extends beyond 2R_e_. Compared to the previously available data, this corresponds to an increase in spatial coverage by a factor from 1 to 5. The present sample represents 86% of the ellipticals in Fornax brighter than B_T_=15mag.
16775. Velocities of Galactic disk late-type stars
ID:
ivo://CDS.VizieR/J/A+A/423/517
Title:
Velocities of Galactic disk late-type stars
Short Name:
J/A+A/423/517
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper, we investigate some chemokinematical properties of the Milky Way disk, by using a sample composed by 424 late-type dwarfs. We show that the velocity dispersion of a stellar group increases steadily the age of the stellar group, according to a disk heating law proportional to t^0.26^, where t is the age of the stellar group. The temporal evolution of the vertex deviation is considered in detail. It is shown that the vertex deviation does not follow a smooth variation with time. Previous studies in the literature seem to not have found it due to the use of statistical ages for stellar groups, rather than individual ages. The possibility to use the orbital parameters of a star to derive information about its birthplace is investigated, and we show that the mean galactocentric radius is likely to be the most reliable stellar birthplace indicator. However, this information cannot be used presently to derive radial evolutionary constraints, due to an intrinsic bias present in all samples constructed from nearby stars.
16776. Velocities of galaxies in A773
ID:
ivo://CDS.VizieR/J/A+A/467/37
Title:
Velocities of galaxies in A773
Short Name:
J/A+A/467/37
Date:
21 Oct 2021
Publisher:
CDS
Description:
To conduct an intensive study of the rich, X-ray luminous galaxy cluster Abell 773 at z=0.22 containing a diffuse radio halo to determine its dynamical status. Our analysis is based on new spectroscopic data obtained at the TNG telescope for 107 galaxies, 37 spectra recovered from the CFHT archive and new photometric data obtained at the Isaac Newton Telescope. We use statistical tools to select 100 cluster members (out to ~1.8h^-1^_70_ from the cluster centre), to analyse the kinematics of cluster galaxies and to determine the cluster structure. Our analysis is also performed by using X-ray data stored in the Chandra archive.
16777. Velocities of galaxies in Abell 520
ID:
ivo://CDS.VizieR/J/A+A/491/379
Title:
Velocities of galaxies in Abell 520
Short Name:
J/A+A/491/379
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 debated. An interesting case is the rich, merging cluster Abell 520, containing a radio halo. A recent gravitational analysis has shown in this cluster the presence of a massive dark core suggested to be a possible problem for the current cold dark matter paradigm. We aim to obtain new insights into the internal dynamics of Abell 520 analyzing velocities and positions of member galaxies. Our analysis is based on redshift data for 293 galaxies in the cluster field obtained combining new redshift data for 8 galaxies acquired at the TNG with data obtained by CNOC team and other few data from the literature. We also use new photometric data obtained at the INT telescope. We combine galaxy velocities and positions to select 167 cluster members around z~0.201. We analyze the cluster structure using the weighted gap analysis, the KMM method, the Dressler-Shectman statistics and the analysis of the velocity dispersion profiles. We compare our results with those from X-ray, radio and gravitational lensing analyses.
16778. Velocities of globular clusters in Fornax
ID:
ivo://CDS.VizieR/J/A+A/464/L21
Title:
Velocities of globular clusters in Fornax
Short Name:
J/A+A/464/L21
Date:
21 Oct 2021
Publisher:
CDS
Description:
We acquired radial velocities of a significant number of globular clusters (GCs) on wide fields between galaxies in the nearby Fornax cluster of galaxies, in order to derive their velocity dispersion radial profile and to probe the dynamics of the cluster. We used FLAMES on the VLT to obtain accurate velocities for 149 GCs, within a ~500x150kpc strip centered on NGC 1399, the Fornax central galaxy. These objects are at the very bright tail (M_V_<~-9.5) of the GC luminosity function, overlapping the so-called "ultra-compact dwarfs" magnitude range. Eight of the brightest FLAMES-confirmed members indeed show hints of resolution in the subarcsecond pre-imaging data we used for selecting the ~500 targets for FLAMES spectroscopy.
16779. Velocities of globular clusters in M104
ID:
ivo://CDS.VizieR/J/AJ/147/150
Title:
Velocities of globular clusters in M104
Short Name:
J/AJ/147/150
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have obtained radial velocity measurements for 51 new globular clusters around the Sombrero galaxy. These measurements were obtained using spectroscopic observations from the AAOmega spectrograph on the Anglo-Australian Telescope and the Hydra spectrograph at WIYN. Combining our own past measurements and velocity measurements obtained from the literature, we have constructed a large database of radial velocities that contains a total of 360 confirmed globular clusters. Previous studies' analyses of the kinematics and mass profile of the Sombrero globular cluster system have been constrained to the inner ~9' (~24kpc or ~5R_e_), but our new measurements have increased the radial coverage of the data, allowing us to determine the kinematic properties of M104 out to ~15' (~41kpc or ~9R_e_). We use our set of radial velocities to study the GC system kinematics and to determine the mass profile and V-band mass-to-light profile of the galaxy. We find that M/L_V_ increases from 4.5 at the center to a value of 20.9 at 41kpc (~9R_e_ or 15'), which implies that the dark matter halo extends to the edge of our available data set. We compare our mass profile at 20kpc (~4R_e_or ~7.4') to the mass computed from X-ray data and find good agreement. We also use our data to look for rotation in the globular cluster system as a whole, as well as in the red and blue subpopulations. We find no evidence for significant rotation in any of these samples.
16780. Velocities of HII regions
ID:
ivo://CDS.VizieR/J/ApJ/582/756
Title:
Velocities of HII regions
Short Name:
J/ApJ/582/756
Date:
21 Oct 2021
Publisher:
CDS
Description:
Kinematic distance determinations in the inner Galaxy are hampered by the near-far kinematic distance ambiguity. Here we resolve the ambiguity for 49 HII region complexes with known recombination-line velocities in the first Galactic quadrant. We measured the 21cm HI absorption spectrum toward each source with the Very Large Array in the C array. The maximum velocity of HI absorption was used to discriminate between the near and far kinematic distances. The number ratio of far to near sources, ~3, can be entirely explained as a geometrical effect. The kinematic distances that we derive are compared with previous determinations for the same sources. Although our distance determinations are largely in agreement with previous measurements, there are 22 discrepancies that we discuss. Using our distance determinations, we create a face-on Galactic map of the HII region complexes and compare it with a kinematically derived profile of the distribution of CO-traced molecular hydrogen. The HII region complexes delineate the large-scale features seen in the molecular gas. The 5kpc molecular ring and the Sagittarius spiral arm are clearly evident, and a few HII region complexes lie in the Perseus arm.

Limit your search

more »

more »

more »

more »

more »

more »