Bibcode
Salo, H.; Laurikainen, E.; Buta, R.; Knapen, J. H.
Bibliographical reference
The Astrophysical Journal Letters, Volume 715, Issue 1, pp. L56-L61 (2010).
Advertised on:
5
2010
Citations
76
Refereed citations
69
Description
Recently, Buta et al. examined the question "Do Bars Drive Spiral
Density Waves?", an idea supported by theoretical studies and also from
a preliminary observational analysis. They estimated maximum bar
strengths Qb , maximum spiral strengths Qs , and
maximum m = 2 arm contrasts A 2s for 23 galaxies with deep
Anglo-Australian Telescope (AAT) Ks -band images. These were
combined with previously published Qb and Qs
values for 147 galaxies from the Ohio State University Bright Spiral
Galaxy Survey (OSUBSGS) sample and with the 12 galaxies from Block et
al. Weak correlation between Qb and Qs was
confirmed for the combined sample, whereas the AAT subset alone showed
no significant correlations between Qb and Qs ,
nor between Qb and A 2s . A similar negative
result was obtained in Durbala et al. for 46 galaxies. Based on these
studies, the answer to the above question remains uncertain. Here we use
a novel approach, and show that although the correlation between the
maximum bar and spiral parameters is weak, these parameters do correlate
when compared locally. For the OSUBSGS sample, a statistically
significant correlation is found between the local spiral amplitude, and
the forcing due to the bar's potential at the same distance, out to
≈1.6 bar radii (the typical bar perturbation is then of the order of
a few percent). Also for the sample of 23 AAT galaxies of Buta et al.,
we find a significant correlation between local parameters out to
≈1.4 bar radii. Our new results confirm that, at least in a
statistical sense, bars do indeed drive spiral density waves.
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