RESONANCES AND EXTENT OF SPIRAL ARMS IN DISK GALAXIES
The distribution of visual matter in 84 spiral galaxies was estimated from NIR Kband maps observed with SOFI/NTT, ESO. Decomposing the maps into standard axisymmetric components (e.g. disk and bulge) and using HI line width data with a maximum disk assumption for the halo, synthetic rotation curves were estimated for each galaxy. The extent of the main spiral pattern measured on the K maps of galaxies was compared with the distance between major resonances (i.e. ILR, 4:1, CR and OLR) as obtained from the synthetic rotation curves assuming that the start of the spiral corresponded to either ILR or CR.
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