Bibcode
Querejeta, M.; Pérez, I.; James, P. A.; Erroz-Ferrer, S.; Blasco-herrera, J.; Beckman, J. E.; Font, J.; Epinat, B.
Bibliographical reference
The Astrophysical Journal Supplement, Volume 210, Issue 1, article id. 2, 30 pp. (2014).
Advertised on:
1
2014
Citations
38
Refereed citations
36
Description
We have developed a method for finding dynamical resonances in disk
galaxies using the change in sense of the radial component of the
in-plane velocity at a resonance radius. Using simulations we show that
we would expect to find these changes at corotation radii with a weaker
effect at the Lindblad resonances. The method works well with
observations at high spectral and angular resolutions, and is suited to
the analysis of two-dimensional velocity fields in Hα from
Fabry-Perot spectroscopy. We find clear indications of resonance effects
in the disk velocity fields of virtually all of the 104 galaxies. The
number of resonance radii detected ranges from one to seven, with a
median of four. The frequency curves Ω, Ω ±
κ/2, Ω ± κ/4 against radius for all the
galaxies led us to discover a pattern in over 70% of the sample: given
two pattern speeds, say Ω1 and Ω2, the
OLR of Ω1 coincides with the corotation of
Ω2, and the inner 4:1 resonance of Ω2
coincides with the corotation of Ω1. Although the
second coincidence has been predicted, a prediction of this double
coincidence is not found in the literature. This pattern is found once
in 42 of the galaxies, twice in a further 26, three times in 5, and even
four times in 1 galaxy. We also compute the ratio of corotation radius
to bar length where we have sufficient image quality, finding a mean
value of 1.3, and a shallow increase toward later type galaxies.
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