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16801. 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.
16802. 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.
16803. Velocity and proper motion of OB associations
ID:
ivo://CDS.VizieR/J/MNRAS/400/518
Title:
Velocity and proper motion of OB associations
Short Name:
J/MNRAS/400/518
Date:
21 Oct 2021
Publisher:
CDS
Description:
The proper motions of OB-associations computed using the old (1997, Cat. <I/239>) and new (2008, Cat. <I/311>) reductions of the Hipparcos data are in a good agreement with each other. The Galactic rotation curve derived from the analysis of line-of-sight velocities and proper motions of OB-associations is almost flat in the 3-kpc neighborhood of the Sun. The angular rotation velocity at the solar distance is Omega_0_=31(+/-1)km/s/kpc. The standard deviation of the velocities of OB-associations from the rotation curve is sigma=7.2km/s. The distance scale for OB associations by Blaha and Humpreys (1989AJ.....98.1598B) should be shortened by 10-20%. The residual velocities of OB-associations calculated for the new and old reductions differ, on average, by 3.5km/s. The mean residual velocities of OB-associations in the stellar-gas complexes depend slightly on the data reduction employed.
16804. Velocity catalog of A545 galaxies
ID:
ivo://CDS.VizieR/J/A+A/529/A128
Title:
Velocity catalog of A545 galaxies
Short Name:
J/A+A/529/A128
Date:
21 Oct 2021
Publisher:
CDS
Description:
The mechanisms giving rise to diffuse radio emission in galaxy clusters, and in particular their connection with cluster mergers, are still debated. We seek to explore the internal dynamics of the cluster Abell 545, which has been shown to host a radio halo. Abell 545 is also peculiar for hosting in its center a very bright, red, diffuse intracluster light due to an old, presumably metal-rich stellar population, so bright to be named as "star pile". Our analysis is mainly based on redshift data for 110 galaxies acquired at the Telescopio Nazionale Galileo. We identify 95 cluster members and analyze the cluster internal dynamics by combining galaxy velocities and positions. We also use both multiband photometric data acquired at the Isaac Newton Telescope and X-ray data from the XMM-Newton Science Archive.
16805. Velocity curves of 10 cataclysmic binaries
ID:
ivo://CDS.VizieR/J/AJ/146/107
Title:
Velocity curves of 10 cataclysmic binaries
Short Name:
J/AJ/146/107
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on ground-based optical observations of 10 cataclysmic binaries that were discovered through their X-ray emission. Time-resolved radial velocity spectroscopy yields unambiguous orbital periods for eight objects and ambiguous results for the remaining two. The orbital periods range from 87 minutes to 9.38 hr. We also obtained time-series optical photometry for six targets, four of which have coherent pulsations. These periods are 1218s for 1RXSJ045707.4+452751, 628s for AXJ1740.2-2903, 477s for AXJ1853.3-0128, and 935s for IGRJ19267+1325. A total of seven of the sources have coherent oscillations in X-rays or optical, indicating that they are intermediate polars (DQ Herculis stars). Time-resolved spectroscopy of one object, SwiftJ2218.4+1925, shows that it is an AM Herculis star, or polar, and IGRJ19552+0044 may also be in that class. For another object, SwiftJ0746.2-1611, we find an orbital period of 9.384 hr and detect the spectrum of the secondary star. The secondary's spectral contribution implies a distance of 900 (+190, -150)pc, where the error bars are estimated using a Monte Carlo technique to account for correlated uncertainties.
16806. Velocity curves of 3 open cluster stars
ID:
ivo://CDS.VizieR/J/A+A/619/A2
Title:
Velocity curves of 3 open cluster stars
Short Name:
J/A+A/619/A2
Date:
21 Oct 2021
Publisher:
CDS
Description:
The aim of this work is to search for planets around intermediate-mass stars in open clusters by using data from an extensive survey with more than 15 years of observations. We obtain high-precision radial velocities (RV) with the HARPS spectrograph for a sample of 142 giant stars in 17 open clusters. We fit Keplerian orbits when a significant periodic signal is detected. We also study the variation of stellar activity indicators and line-profile variations to discard stellar-induced signals. We present the discovery of a periodic RV signal compatible with the presence of a planet candidate in the 1.15Gyr open cluster IC4651 orbiting the 2.06M_{sun}_ star No. 9122. If confirmed, the planet candidate would have a minimum mass of 7.2M_J_ and a period of 747 days. However, we also find that the FWHM of the CCF varies with a period close to the RV, casting doubts on the planetary nature of the signal. We also provide refined parameters for the previously discovered planet around NGC2423 No. 3 but show evidence that the BIS of the CCF is correlated with the RV during some of the observing periods. This fact advises us that this might not be a real planet and that the RV variations could be caused by stellar activity and/or pulsations. Finally, we show that the previously reported signal by a brown dwarf around NGC4349 No. 127 is presumably produced by stellar activity modulation. The long-term monitoring of several red giants in open clusters has allowed us to find periodic RV variations in several stars. However, we also show that the follow-up of this kind of stars should last more than one orbital period to detect long-term signals of stellar origin. This work warns that although it is possible to detect planets around red giants, large-amplitude, long-period RV modulations do exist in such stars that can mimic the presence of an orbiting planetary body. Therefore, we need to better understand how such RV modulations behave as stars evolve along the Red Giant Branch and perform a detailed study of all the possible stellar-induced signals (e.g. spots, pulsations, granulation) to comprehend the origin of RV variations.
16807. Velocity curves of SW CMa and HW CMa
ID:
ivo://CDS.VizieR/J/A+A/537/A117
Title:
Velocity curves of SW CMa and HW CMa
Short Name:
J/A+A/537/A117
Date:
21 Oct 2021
Publisher:
CDS
Description:
Accurate physical properties of eclipsing stars provide important constraints on models of stellar structure and evolution, especially when combined with spectroscopic information on their chemical composition. Empirical calibrations of the data also lead to accurate mass and radius estimates for exoplanet host stars. Finally, accurate data for unusual stellar subtypes, such as Am stars, also help to unravel the cause(s) of their peculiarities. We aim to determine the masses, radii, effective temperatures, detailed chemical composition and rotational speeds for the Am-type eclipsing binaries SWCMa (A4-5m) and HWCMa (A6m) and compare them with similar normal stars.
16808. Velocity data of rich clusters
ID:
ivo://CDS.VizieR/J/MNRAS/224/453
Title:
Velocity data of rich clusters
Short Name:
J/MNRAS/224/453
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present redshifts and stellar velocity dispersions for about 40 galaxies in each of 14 rich clusters from the southern cluster survey of Abell & Corwin (1983, Early Evolution of the Universe and Its Present Structure, p.179, Eds. Abell & Chincarini, Reidel, Dordrecht, Holland). The clusters cover a wide range of richnesses and Abell and Bautz-Morgan types, our aim being to compile a large, homogeneous database for examining and comparing dynamical phenomena and morphological properties. Further papers will present photometry for the clusters and an analysis of the database.
16809. Velocity dispersion in AGN
ID:
ivo://CDS.VizieR/J/ApJ/585/647
Title:
Velocity dispersion in AGN
Short Name:
J/ApJ/585/647
Date:
21 Oct 2021
Publisher:
CDS
Description:
It has been proposed that the width of the narrow [O III] {lambda}5007 emission line can be used as a surrogate for the stellar velocity dispersion in active galaxies. This proposition is tested using the Sloan Digital Sky Survey (SDSS) Early Data Release (EDR) spectra of 107 low-redshift radio-quiet QSOs and Seyfert 1 galaxies by investigating the correlation between black hole mass, as determined from H{beta} FWHM and optical luminosity, and [O III] FWHM. The correlation is real, but the scatter is large. Without additional information or selection criteria, the [O III] width can predict the black hole mass to a factor of 5.
16810. Velocity dispersions and Mg2 index of galaxies
ID:
ivo://CDS.VizieR/J/AJ/126/2268
Title:
Velocity dispersions and Mg2 index of galaxies
Short Name:
J/AJ/126/2268
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present central velocity dispersions and Mg_2_ line indices for an all-sky sample of 1175 elliptical and S0 galaxies, of which 984 had no previous measures. This sample contains the largest set of homogeneous spectroscopic data for a uniform sample of elliptical galaxies in the nearby universe. These galaxies were observed as part of the ENEAR (Redshift-Distance Survey of Nearby Early-Type Galaxies) project, designed to study the peculiar motions and internal properties of the local early-type galaxies. Using 523 repeated observations of 317 galaxies obtained during different runs, the data are brought to a common zero point. These multiple observations, taken during the many runs and different instrumental setups employed for this project, are used to derive statistical corrections to the data and are found to be relatively small, typically <~5% of the velocity dispersion and 0.01mag in the Mg_2_ line strength. Typical errors are about 8% in velocity dispersion and 0.01mag in Mg_2_, in good agreement with values published elsewhere.

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