Rotation curves have been obtained for 76 spiral galaxies in pairs, including a geometrically selected subset from the Karachentsev catalog and a set of Seyfert galaxies with close companions. Derived parameters of the rotation curves and the galaxies' light distributions are also presented. The rotation curves are classified broadly by shape, with special emphasis on kinematic disturbances and regions of solid-body behavior that may lead to bar development. Broadband images of the galaxies allow assessments of their degree of symmetry or disturbance. These velocity slices afford an empirical basis for evaluating the accuracy of radial velocity measures for spiral galaxies in pairs, and the dynamically important radial velocity differences. Specifically, the disagreement among several plausible ways of estimating the central velocity from these rotation data is used to estimate how closely any of these might approximate the nuclear or center-of-mass values. From seven indicators of central velocity, the internal scatter is delta_vv = 34 km/s. Of these, the velocity weighted by Halpha intensity along the slit shows a systematic offset of about 20 km/s with respect to the others for the Karachentsev pairs, in the sense that this measure is redshifted with respect to the other indicators. This is in the sense (but not of the total magnitude) required to account for statistical asymmetries in pair velocity differences. Individual scatter between the velocity indicators taken pairwise ranges from delta = 20 to 52 km/s. These results imply that emission-line data such as these cannot specify the center of mass or nuclear redshift at a level more accurate than this, even for arbitrarily precise velocity measurements, because it is not clear how the observed quantities relate to the desired measurement in a physical sense. No useful predictor of which galaxies have large or small scatter among velocity measures was found, except that the scatter is small for the class of "nonrotating" galaxies with small overall velocity amplitudes. Projected separation, separation normalized to disk scale length, and morphological disturbance do not correlate with velocity scatter.
File table5.dat contains the NGC (Cat. <VII/118>) numbers of the 40 galaxies observed in JHK with the MAGIC camera of the Calar Alto 2.2m telescope. Their absolute total JHK luminosities, the luminosities of disks and bulges, and the bulge-to-disk ratios were obtained by flux-calibrated 2-dimensional disk-bulge decompositions.
A sample of 54 nearby spiral galaxies was observed in the K' band with 3.5m NTT telescope, La Silla, ESO, to study the morphology and other properties of spiral perturbations in their disks. A subsample of the galaxies classified as ordinary, non-barred spirals was used to estimate frequency of weak bars detectable in the K' band. The tables provide general structural properties of the galaxies including estimated of the bulge/disk decomposition and spiral perturbations in the disks.
We present new long-slit H{alpha} spectroscopy for 403 non-interacting spiral galaxies, obtained at the Palomar Observatory 5m Hale telescope, which is used to derive well-sampled optical rotation curves. Because many of the galaxies show optical emission features that are significantly extended along the spectrograph slit, a technique was devised to separate and subtract the night sky lines from the galaxy emission. We exploit a functional fit to the rotation curve to identify its center of symmetry; this method minimizes the asymmetry in the final, folded rotation curve. We derive rotational widths using both velocity histograms and the Polyex model fit. The final rotational width is measured at a radius containing 83% of the total light as derived from I-band images.
We present the rotation curves of 967 southern spiral galaxies, obtained by deprojecting and folding the raw H{alpha} data originally published by Mathewson, Ford, & Buchhorn (1992ApJS...81..413M). For 900 objects, we also present, in figures and tables, the rotation curves smoothed on scales corresponding to 5%-20% of the optical size; of these, 80 meet objective excellence criteria and are suitable for individual detailed mass modeling, while 820, individually less compelling mainly because of the moderate statistics and/or limited extension, are suitable for statistical studies. The remaining 67 curves suffer from severe asymmetries, small statistics, and large internal scatter that may largely limit their use in galaxy structure studies. The deprojected folded curves, the smoothed curves, and various related quantities are available via anonymous ftp at galileo.sissa.it in the directory /users/ftp/pub/psrot.
The location of young sources in the Galaxy suggests a four-armed spiral structure, whereas tangential points of spiral arms observed in the integrated light at infrared and radio wavelengths indicate that only two arms are massive. Variable extinction in the Galactic plane and high light-to-mass ratios of young sources make it difficult to judge the total mass associated with the arms outlined by such tracers. The current objective is to estimate the mass associated with the Sagittarius arm by means of the kinematics of the stars across it. Spectra of 1726 candidate B- and A-type stars within 3{deg} of the Galactic center (GC) were obtained with the FLAMES instrument at the VLT with a resolution of ~6000 in the spectral range of 396-457nm. Radial velocities were derived by least-squares fits of the spectra to synthetic ones. The final sample was limited to 1507 stars with either Gaia DR2 parallaxes or main-sequence B-type stars having reliable spectroscopic distances. The solar peculiar motion in the direction of the GC relative to the local standard of rest (LSR) was estimated to U_{sun}_=10.7+/-1.3km/s. The variation in the median radial velocity relative to the LSR as a function of distance from the sun shows a gradual increase from slightly negative values near the sun to almost 5km/s at a distance of around 4kpc. A sinusoidal function with an amplitude of 3.4+/-1.3km/s and a maximum at 4.0+/-0.6kpc inside the sun is the best fit to the data. A positive median radial velocity relative to the LSR around 1.8kpc, the expected distance to the Sagittarius arm, can be excluded at a 99% level of confidence. A marginal peak detected at this distance may be associated with stellar streams in the star-forming regions, but it is too narrow to be associated with a major arm feature. A comparison with test-particle simulations in a fixed galactic potential with an imposed spiral pattern shows the best agreement with a two-armed spiral potential having the Scutum-Crux arm as the next major inner arm. A relative radial forcing dFr~1.5% and a pattern speed in the range of 20-30km/s/kpc yield the best fit. The lack of a positive velocity perturbation in the region around the Sagittarius arm excludes it from being a major arm. Thus, the main spiral potential of the Galaxy is two-armed, while the Sagittarius arm is an inter-arm feature with only a small mass perturbation associated with it.
We present the analysis of the rotation curves of a sample of 32 spiral galaxies derived from the spectroscopic observations of a sample of 47 galaxies.
We used spatially resolved ALMA observations of the three CO isotopologues ^12^CO, ^13^CO and C^18^O (J=2-1) from CQ Tau to analyse the brightness temperature and kinematics of the gas disc. We detect significant spiral structures in both the brightness temperature and the rotation velocity of ^12^CO after subtraction of an azimuthally symmetric model, which may be tracing planet-disc interactions with an embedded planet or low-mass companion. The brightness temperature spirals are morphologically connected to spirals observed in NIR scattered light in the same disc, indicating a common origin. Together with the observed large dust and gas cavity, these spiral structures support the hypothesis of a massive embedded companion in the CQ Tau disc.
The morphology and kinematics of the spiral structure of the Milky Way are long-standing problems in astrophysics. In this review we firstly summarize various methods with different tracers used to solve this puzzle. The astrometry of Galactic sources is gradually alleviating this difficult situation caused mainly by large distance uncertainties, as we can currently obtain accurate parallaxes (a few {mu}as) and proper motions (~1km/s) by using Very Long Baseline Interferometry (VLBI). On the other hand, the Gaia mission is providing the largest, uniform sample of parallaxes for O-type stars in the entire Milky Way. Based upon the VLBI maser and Gaia O-star parallax measurements, nearby spiral structures of the Perseus, Local, Sagittarius and Scutum Arms are determined in unprecedented detail. Meanwhile, we estimate fundamental Galactic parameters of the distance to the Galactic center, R_0_, to be 8.35+/-0.18kpc, and circular rotation speed at the Sun, {THETA}_0_, to be 240+/-10km/s. We found kinematic differences between O stars and interstellar masers: the O stars, on average, rotate faster, >8km/s than maser-traced high-mass star forming regions.
We have updated the catalogs of Galactic HII regions, giant molecular clouds (GMCs), and 6.7-GHz methanol masers to outline the spiral structure of our Galaxy. The related parameters have been collected and (re)calculated based on the data in the literature. In particular, for each spiral tracer, we list the photometric or trigonometric distance, and/or the solutions of the kinematic distance ambiguity (KDA) when available. The kinematic distances when adopted are calculated using a flat rotation curve with two sets of R_0_, {Theta}_0_, and solar motions, where one set is the IAU standard and the other is from the new observational results. The rotation curve of Brand & Blitz (1993, Cat. J/A+A/275/67) is also used to derive the kinematic distances.