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Over the last decade it has become clear that there is a decoupling between the old stellar disk and young stellar disk in spiral galaxies. This has led to a scheme for classifying galaxies on the basis of their near-infrared morphology. The near-infrared provides a more physical framework for classifying galaxies as it is both relatively free from extinction and it traces the old stellar population, i.e. the dominant stellar mass distribution. The `dust penetrated class is dependent upon the spiral pitch angle of arms. We have observed 8 galaxies with UFTI on UKIRT in the K-band in order to investigate the theoretical link between disk dynamics and arm morphology, which is suggested both from numerical models and the dust penetrated class. We find that the pitch angle of spiral arms, i, correlates well with the shear rate of rotation curves, $A/omega$ (where A is the first Oort constant and $omega$ is the rotational velocity), over the same radial range.
Anemic galaxies have less prominent star formation than normal galaxies of the same Hubble type. Previous studies showed they are deficient in total atomic hydrogen but not in molecular hydrogen. Here we compare the combined surface densities of HI a
We re-examine past suggestions of a close link between terrestrial climate change and the Suns transit of spiral arms in its path through the Milky Way galaxy. These links produced concrete fits, deriving the unknown spiral pattern speed from terrest
The observed rotation curves of disc galaxies, ranging from late-type dwarf galaxies to early-type spirals, can be fit remarkably well simply by scaling up the contributions of the stellar and HI discs. This `baryonic scaling model can explain the fu
We present a relationship between spiral arm pitch angle (a measure of the tightness of spiral structure) and the mass of supermassive black holes (BHs) in the nuclei of disk galaxies. We argue that this relationship is expected through a combination
We present the correlation between the extrapolated central disk surface brightness (mu) and extrapolated central surface mass density (Sigma) for galaxies in the DiskMass sample. This mu-Sigma-relation has a small scatter of 30% at the high-surface-