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J/A+A/330/881       Radial velocities of Cartwheel Galaxy (Amram+ 1998)

The Hα kinematics of the Cartwheel galaxy Amram P., Mendes de Oliveira C., Boulesteix J., Balkowski C. <Astron. Astrophys. 330, 881 (1998)> =1998A&A...330..881A (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, ring ; Radial velocities Keywords: galaxies: interactions - galaxies: ISM - galaxies: kinematics and dynamics - galaxies: individual (Cartwheel) - galaxies: structure Abstract: We report on high spectral and spatial resolution kinematic observations of Hα emission from the Cartwheel system obtained with a scanning Fabry-Perot interferometer. Velocity fields for two galaxies were measured, for the main galaxy of the system, the Cartwheel galaxy, and for a spiral companion ∼25h-1kpc to the north. The velocity field and the rotation curve of the spiral companion shows classical differential rotation and indicates the mass of the galaxy to be in the range 2.9-4.8x109M☉. The Cartwheel galaxy contains strong Hα in emission asymmetrically distributed along its outer ring, with some faint emission detected inside it. The velocity field and the rotation curve of the Cartwheel galaxy is clearly dominated by differential rotation although second-order effects cause distortions which can be understood in a scenario where expansion and density-wave motions are also considered. Our best model-fit to the observed velocity field of the Cartwheel galaxy includes three components for the kinematic of its outer ring: a circular velocity of 217km/s, an expansion velocity of 13-30±10km/s and a sinusoidal perturbation with an amplitude of 20±5km/s. This expansion velocity, lower than found in previous studies, implies that the ring could be older than previously thought. The rotation curve of the Cartwheel galaxy is consistent with a progenitor which had the morphology of a late-type spiral galaxy. Our measurements support the collisional models of ring galaxy formation and should impose strong constraints to simulations. Objects: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 00 37 40.7 -33 42 58 Cartwheel galaxy = ESO 350- 40 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3a 39 21 Radial characteristics of the Cartwheel (Fig. 5) table3b 39 25 Radial characteristics for the spiral companion (Fig. 11) table3.tex 106 96 LaTeX version of the tables
Byte-by-byte Description of file: table3a table3b
Bytes Format Units Label Explanations
1- 4 F4.1 arcsec Rad Mean radius of the annulus on the major axis 6- 7 I2 --- Napp Number of points with measurable radial velocities in this annulus for the approaching side 9- 11 I3 km/s Vapp ? Weighted average velocity calculated from Napp velocity points 13- 14 I2 km/s e_Vapp ? rms uncertainty on Vapp 16- 18 I3 --- Nrec Number of points with measurable radial velocities in this annulus for the receding side 20- 22 I3 km/s Vrec ? Weighted average velocity calculated from Nrec velocity points 24- 26 I3 km/s e_Vrec ? rms uncertainty on Vrec 28- 30 I3 --- Ntot Total number of velocity points in the annulus Napp+Nrec 33- 35 I3 km/s Vel Weighted average velocity calculated from both sides 37- 39 I3 km/s e_Vel rms uncertainty on Vel
Acknowledgements: Philippe Amram
(End) Patricia Bauer [CDS] 20-Aug-1997
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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