- ID:
- ivo://CDS.VizieR/J/MNRAS/384/943
- Title:
- Velocities of NGC 1023 planetary nebulae
- Short Name:
- J/MNRAS/384/943
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the manner in which lenticular galaxies are formed by studying their stellar kinematics: an S0 formed from a fading spiral galaxy should display similar cold outer disc kinematics to its progenitor, while an S0 formed in a minor merger should be more dominated by random motions. In a pilot study to attempt to distinguish between these scenarios, we have measured the planetary nebula (PN) kinematics of the nearby S0 system NGC 1023. Using the Planetary Nebula Spectrograph, we have detected and measured the line-of-sight velocities of 204 candidate PNe in the field of this galaxy. Out to intermediate radii, the system displays the kinematics of a normal rotationally-supported disc system. After correction of its rotational velocities for asymmetric drift, the galaxy lies just below the spiral galaxy Tully-Fisher relation, as one would expect for a fading system. However, at larger radii the kinematics undergo a gradual but major transition to random motion with little rotation. This transition does not seem to reflect a change in the viewing geometry or the presence of a distinct halo component, since the number counts of PNe follow the same simple exponential decline as the stellar continuum with the same projected disc ellipticity out to large radii. The galaxy's small companion, NGC 1023A, does not seem to be large enough to have caused the observed modification either. This combination of properties would seem to indicate a complex evolutionary history in either the transition to form an S0 or in the past life of the spiral galaxy from which the S0 formed. More data sets of this type from both spirals and S0s are needed in order to definitively determine the relationship between these types of system.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/549/A115
- Title:
- Velocities of Planetary Nebula in 5 galaxies
- Short Name:
- J/A+A/549/A115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The origins of S0 galaxies remain obscure, with various mechanisms proposed for their formation, likely depending on environment. These mechanisms would imprint different signatures in the galaxies' stellar kinematics out to large radii, offering a method for distinguishing between them. We aim to study a sample of six S0 galaxies from a range of environments, and use planetary nebulae (PNe) as tracers of their stellar populations out to very large radii, to determine their kinematics in order to understand their origins. Using a special-purpose instrument, the Planetary Nebula Spectrograph, we observe and extract PNe catalogues for these six systems. We show that the PNe have the same spatial distribution as the starlight, that the numbers of them are consistent with what would be expected in a comparable old stellar population in elliptical galaxies, and that their kinematics join smoothly onto those derived at smaller radii from conventional spectroscopy. The high-quality kinematic observations presented here form an excellent set for studying the detailed kinematics of S0 galaxies, in order to unravel their formation histories. We find that PNe are good tracers of stellar kinematics in these systems. We show that the recovered kinematics are largely dominated by rotational motion, although with significant random velocities in most cases.
- ID:
- ivo://CDS.VizieR/J/MNRAS/439/1015
- Title:
- Velocities of red giants in 7 LG dwarf galaxies
- Short Name:
- J/MNRAS/439/1015
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measured velocities of 862 individual red giant stars in seven isolated dwarf galaxies in the Local Group: NGC 6822, IC 1613, VV 124 (UGC 4879), the Pegasus dwarf irregular galaxy (DDO 216), Leo A, Cetus, and Aquarius (DDO 210). We also computed velocity dispersions, taking into account the measurement uncertainties on individual stars. None of the isolated galaxies is denser than the densest Local Group satellite galaxy. Furthermore, the isolated dwarf galaxies have no obvious distinction in the velocity dispersion-half-light radius plane from the satellite galaxies of the Milky Way and M31. The similarity of the isolated and satellite galaxies' dynamics and structural parameters imposes limitations on environmental solutions to the too-big-to-fail problem, wherein there are fewer dense dwarf satellite galaxies than would be expected from cold dark matter simulations. This data set also has many other applications for dwarf galaxy evolution, including the transformation of dwarf irregular into dwarf spheroidal galaxies. We intend to explore these issues in future work.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- ID:
- ivo://CDS.VizieR/J/A+AS/113/151
- Title:
- Velocity dispersions for elliptical galaxies
- Short Name:
- J/A+AS/113/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measurements of central velocity dispersions and heliocentric radial velocities are presented for 94 field galaxies. Among these, 5 new radial velocities and 80 new central velocity dispersions are obtained. Reduction was performed independently by cross-correlation, Fourier-quotient and Fourier-correlation-quotient methods.
