- ID:
- ivo://CDS.VizieR/J/A+A/621/A25
- Title:
- Arp 240 Fabry-Perot interferometry
- Short Name:
- J/A+A/621/A25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Encounters between galaxies modify their morphology, kinematics, and star formation history. The relation between these changes and external perturbations is not straightforward. The great number of parameters involved requires both the study of large samples and individual encounters where particular features, motions, and perturbations can be traced and analysed in detail. We analysed the morphology, kinematics, and dynamics of two luminous infrared spiral galaxies of almost equal mass, NGC 5257 and NGC 5258, in which star formation is mostly confined to the spiral arms, in order to understand interactions between galaxies of equivalent masses and star-forming processes during the encounter. Using scanning Fabry-Perot interferometry, we studied the contribution of circular and non-circular motions and the response of the ionized gas to external perturbations. We compared the kinematics with direct images of the pair and traced the star-forming processes and gravitational effects due to the presence of the other galaxy. The spectral energy distribution of each member of the pair was fitted. A mass model was fitted to the rotation curve of each galaxy. Large, non-circular motions detected in both galaxies are associated with a bar, spiral arms, and HII regions for the inner parts of the galaxies, and with the tidal interaction for the outer parts of the discs. Bifurcations in the rotation curves indicate that the galaxies have recently undergone their pericentric passage. The pattern speed of a perturbation of one of the galaxies is computed. Location of a possible corotation seems to indicate that the gravitational response of the ionized gas in the outer parts of the disc is related to the regions where ongoing star formation is confined. The spectral energy distribution (SED) fit indicates a slightly different star formation history for each member of the pair. For both galaxies, a pseudo-isothermal halo better fits the global mass distribution.
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- ID:
- ivo://CDS.VizieR/J/A+A/631/A94
- Title:
- Avg pitch angles & spiral amplitudes in S4G
- Short Name:
- J/A+A/631/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spiral galaxies are very common in the local Universe, but their formation, evolution, and interplay with bars remain poorly understood after more than a century of astronomical research on the topic. We use a sample of 391 nearby galaxies from the S4G survey to characterise the winding angle and amplitude of spiral arms as a function of disc properties, such as bar strength, in all kinds of spirals (grand-design, multi-armed, and flocculent). We derived global pitch angles in 3.6um de-projected images from i) average measurements of individual logarithmic spiral segments, and ii) for a subsample of 32 galaxies, from 2-D Fourier analyses. The strength of spirals was quantified from the tangential-to-radial force ratio and from the normalised m=2 Fourier density amplitudes. In galaxies with more than one measured logarithmic segment, the spiral pitch angle varies on average by ~10{deg} between segments, but by up to >=15-20{deg}. The distribution of the global pitch angle versus Hubble type (T) is very similar for barred and non-barred galaxies when 1<=T<=5. Most spiral galaxies (>90%) are barred for T>5. The pitch angle is not correlated with bar strength, and only weakly with spiral strength. The amplitude of spirals is correlated with bar strength (and less tightly, with bar length) for all types of spirals. The mean pitch angle is hardly correlated with the mass of the supermassive black hole (estimated from central stellar velocity dispersion), with central stellar mass concentration, or with shear, questioning previous results in the literature using smaller samples. We do not find observational evidence that spiral arms are driven by stellar bars or by invariant manifolds. Most likely, discs that are prone to the development of strong bars are also reactive to the formation of prominent spirals, explaining the observed coupling between bar and spiral amplitudes.
- ID:
- ivo://CDS.VizieR/J/A+A/406/829
- Title:
- Background galaxies in the WSRT wide-field Survey
- Short Name:
- J/A+A/406/829
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the Westerbork array to carry out an unbiased wide-field survey for H I emission features, achieving an RMS sensitivity of about 18mJy/beam at a velocity resolution of 17km/s over 1800deg2 and between -1000<VHel<+6500 km/s. The primary data consists of auto-correlation spectra with an effective angular resolution of 49' FWHM. The survey region is centered approximately on the position of Messier 31 and is Nyquist-sampled over 60x30 deg in RAxDec. In this paper we present the results for our HI detections of external galaxies at positive Local Group Standard of Rest (LGSR) velocity. We detect 155 external galaxies in excess of 8 sigma in integrated HI flux density. Plausible optical associations are found within a 30' search radius for all but one of our HI detections in DSS images, although several are not previously catalogued or do not have published redshift determinations. Our detection without a DSS association is at low galactic latitude. Twenty-three of our objects are detected in HI for the first time. We classify almost half of our detections as "confused", since one or more companions is catalogued within a radius of 30' and a velocity interval of 400km/s. Nine of the detected galaxies fall so near the edges of the survey coverage (either spatially or in velocity) that their parameters can not be reliably determined. These nine objects are excluded from the enclosed table.
- ID:
- ivo://CDS.VizieR/J/A+A/593/A114
- Title:
- CALIFA space density distribution of galaxies
- Short Name:
- J/A+A/593/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the distribution in absolute magnitude-circular velocity space for a well-defined sample of 199 rotating Calar Alto Legacy Integral Field Area Survey (CALIFA) galaxies using their stellar kinematics. Our aim in this analysis is to avoid subjective selection criteria and to take volume and large-scale structure factors into account. Using stellar velocity fields instead of gas emission line kinematics allows including rapidly rotating early type galaxies. Our initial sample contains 277 galaxies with available stellar velocity fields and growth curve r-band photometry. After rejecting 51 velocity fields that could not be modelled due to the low number of bins, foreground contamination or significant interaction we perform Markov Chain Monte Carlo (MCMC) modelling of the velocity fields, obtaining the rotation curve and kinematic parameters and their realistic uncertainties. We perform an extinction correction and calculate the circular velocity v_circ_ accounting for pressure support a given galaxy has. The resulting galaxy distribution on the M_r_-v_circ_ plane is then modelled as a mixture of two distinct populations, allowing robust a nd reproducible rejection of outliers, a significant fraction of which are slow rotators. The selection effects are understood well enough that the incompleteness of thesample can be corrected for and the 199 galaxies can be weighted by volume and large-scale structure factors enabling us to fit a volume-corrected Tully-Fisher relation (TFR). More importantly, we also provide the volume-corrected distribution of galaxies in the M_r_-v_circ_ plane, which can be compared with cosmological simulations. The joint distribution of the luminosity and circular velocity space densities, representative over the range of -20>M_r_>-22mag, can place more stringent constraints on the galaxy formation and evolution scenarios than linear TFR fit parameters or the luminosity function alone.
- ID:
- ivo://CDS.VizieR/J/other/RAA/10.541
- Title:
- Carbon star list (90<l<270, |b|<6)
- Short Name:
- J/other/RAA/10.5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The availability of astrometric data and radial velocities of carbon stars near the Galactic plane enables us to investigate the kinematics of the Milky Way, especially the rotation curve. The recently published Third U.S. Naval Observatory CCD Astrograph Catalog (UCAC3) provides the opportunity to test this problem using three-dimensional velocity in order to obtain more reliable rotation curves. We intend to study the Galactic rotation curve up to 15kpc using the radial velocities and proper motions of carbon stars. The motivation for using UCAC3 is to provide high precision proper motions which have hardly been used in determining the rotation velocity of tracers. Seventy-four carbon stars and carbon-rich Mira variables toward the anti-center direction (90{deg}<l<270{deg}, |b|<6{deg}) are picked up from the literature then matched with UCAC3 carbon star candidates to obtain their proper motions. A rigorous geometrical method is employed to compute the rotation velocity of each object. Taking carbon stars as tracers, we find a flat rotation curve of 210+/-12km/s assuming R0=8.0kpc for the galactocentric distance and V0=220km/s for the rotation velocity of the Sun. Due to the uncertainties of distances, the rotation velocities are more dispersed if tangential velocities enter the calculation, compared to those derived from radial velocities only. However, the whole rotation curve shows coherence with previous results. Increasing observation and study of carbon stars would be desirable in order to provide more homogeneous data for the kinematical study of the Galactic disk.
- ID:
- ivo://CDS.VizieR/VII/72
- Title:
- Catalog of Stellar Velocity Dispersions
- Short Name:
- VII/72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalog of central stellar velocity dispersion measurements is presented, current through 1984. The catalog includes 1096 measurements of 725 galaxies. A set of 51 standard galaxies is defined which consists of galaxies with at least three reliable, concordant measurements.
- ID:
- ivo://CDS.VizieR/J/A+A/634/A10
- Title:
- Chemo-kinematic properties of Aquarius
- Short Name:
- J/A+A/634/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dwarf galaxies found in isolation in the Local Group (LG) are unlikely to have interacted with the large LG spirals, and therefore environmental effects such as tidal and ram-pressure stripping should not be the main drivers of their evolution. We aim to provide insight into the internal mechanisms shaping LG dwarf galaxies by increasing our knowledge of the internal properties of isolated systems. Here we focus on the evolved stellar component of the Aquarius dwarf galaxy, whose kinematic and metallicity properties have only recently started to be explored. Spectroscopic data in the region of the near-infrared Ca~II triplet lines has been obtained with FORS2 at the Very Large Telescope for 53 red giant branch (RGB) stars. These data are used to derive line-of-sight velocities and [Fe/H] of the individual RGB stars. We have derived a systemic velocity of -142.2^+1.8^_-1.8_km/s, in agreement with previous determinations from both the HI gas and stars. The internal kinematics of Aquarius appears to be best modelled by a combination of random motions (l.o.s. velocity dispersion of 10.3^+1.6^_-1.3_km/s) and linear rotation (with a gradient -5.0^+1.6^_-1.9_km/s/arcmin) along a P.A.=139_-27_^+17^deg, broadly consistent with the optical projected major axis. This rotation signal is significantly misaligned or even counter-rotating to that derived from the HI gas. We also find the tentative presence of a mild negative metallicity gradient and indications that the metal-rich stars have a colder velocity dispersion than the metal-poor ones. This work represents a significant improvement with respect to previous measurements of the RGB stars of Aquarius, as it doubles the number of member stars already studied in the literature. We speculate that the misaligned rotation between the HI gas and evolved stellar component might have been the result of recent accretion of HI gas, or re-accretion after gas-loss due to internal stellar feedback.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A161
- Title:
- Coadded rotation curves of disk galaxies
- Short Name:
- J/A+A/643/A161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Lambda-cold dark matter (Lambda CDM) scenario is able to describe the Universe at large scales, but clearly shows some serious difficulties at small scales. The core/cusp issue is one of those: as a fact, the inner dark matter (DM) density profiles of spiral galaxies generally appear to be cored, without the r^-1^ profile as predicted by N-body simulations in the above scenario. It is well known that, in a more physical context, the baryons in the galaxy, through supernovae explosions could back react and erase the original cusp. Before investigating the efficiency and the presence of such effect, it is important to know how wide and how frequent the discrepancy between observed and N-body predicted profiles is and what its features are. We use more than 3200 good quality and high resolution, quite extended rotation curves (RCs) of disk systems including normal and dwarf spirals as well as low surface brightness galaxies covering their whole ranges of magnitudes. All these RCs are condensed in 26 coadded RCs, each of them built with individual RCs of galaxies of similar luminosity and morphology. We mass model these 26 RCs using the NFW profile for the contribution of the DM halo to the circular velocity and the exponential Freeman disk for that of the stellar disk. The fits are generally poor in all the 26 cases: in several cases we find chi^2^_red_> 2. Moreover, the best fitting values of three parameters of the model (c, M_D_, M_{vir}_) combined with those of their 1-sigma uncertainty show clear conflict with well-known expectations of Lambda-CDM scenario. We also test the scaling relations which exist in spirals with the outcome of the current mass modelling: the latter is found not to account for such scaling relations. The results of testing NFW profile in disk systems indicate that such DM halo density law cannot account for the kinematics of the whole family of disk galaxies. The need of transforming initial cusps in the observed cores is therefore mandatory for the success of the Lambda-CDM scenario, in any disk galaxy of any luminosity or maximum rotational velocity.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/31
- Title:
- Dark matter halo models for SPARC galaxies
- Short Name:
- J/ApJS/247/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present rotation curve fits to 175 late-type galaxies from the Spitzer Photometry and Accurate Rotation Curves database using seven dark matter (DM) halo profiles: pseudo-isothermal, Burkert, Navarro-Frenk-White (NFW), Einasto, Di Cintio+ (DC14; 2014MNRAS.441.2986D), cored-NFW, and a new semi-empirical profile named Lucky13. We marginalize over the stellar mass-to-light ratio, galaxy distance, disk inclination, halo concentration, and halo mass (and an additional shape parameter for Einasto) using a Markov Chain Monte Carlo method. We find that cored halo models, such as the DC14 and Burkert profiles, generally provide better fits to rotation curves than the cuspy NFW profile. The stellar mass-halo mass relation from abundance matching is recovered by all halo profiles once imposed as a Bayesian prior, whereas the halo mass-concentration relation is not reproduced in detail by any halo model.
- ID:
- ivo://CDS.VizieR/J/MNRAS/398/91
- Title:
- 2D kinematic structure of early-type galaxies
- Short Name:
- J/MNRAS/398/91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We detail an innovative new technique for measuring the two-dimensional (2D) velocity moments (rotation velocity, velocity dispersion and Gauss-Hermite coefficients h3 and h4) of the stellar populations of galaxy haloes using spectra from Keck DEIMOS (Deep Imaging Multi-Object Spectrograph) multi-object spectroscopic observations. The data are used to reconstruct 2D rotation velocity maps. Here we present data for five nearby early-type galaxies to ~three effective radii.
