2007/12/04 by John E. Beckman, Kambiz Fathi, Beckman, John E. +9
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.0712.0518
To appear in the ASP conference proceedings, "Formation and Evolution of Galaxy Disks", held in Rome 1-5 October 2007. Editors Jose G. Funes, S.J. and Enrico M. Corsini
arxiv created 2008/01/18 · arxiv updated 2011/11/09
The Fabry-Perot interferometer FaNTOmM was used at the 3.6m Canada France Hawaii Telescope and the 1.6m Mont Megantic Telescope to obtain data cubes in H-alpha of 9 nearby spiral galaxies from which maps in integrated intensity, velocity, and velocity dispersion were derived. We then applied the Tremaine-Weinberg method, in which the pattern speed can be deduced from its velocity field, by finding the integrated value of the mean velocity along a slit parallel to the major axis weighted by the intensity and divided by the weighted mean distance of the velocity points from the tangent point measured along the slit. The measured variables can be used either to make separate calculations of the pattern speed and derive a mean, or in a plot of one against the other for all the points on all slits, from which a best fit value can be derived. Linear fits were found for all the galaxies in the sample. For two galaxies a clearly separate inner pattern speed with a higher value, was also identified and measured.