Wednesday, March 17, 2010 - 3:15pm
Kambiz Fathi (Stockhokm):
"The Scale Length of Galaxies"
Abstract. Virtual Observatory methods and tools have been used to define, retrieve, and analyse the images for 30374 non-interacting disk/spiral galaxies. Cross-correlation of the SDSS sample with the LEDA catalogue allowed us to investigate the variation of the scale lengths for different types of disk/spiral galaxies. We further investigated asymmetry,concentration, and velocity dispersion as indicators of morphological type, and were able to assess how the scale length varies with respect to galaxy type. We note however, that the concentration and asymmetry parameters should be used with caution to investigate type dependency of structural parameters in galaxies. Here, we present the scale length derivation method and numerous tests that we have carried out to investigate the reliability of our results. The average r-band disk scale length is 3.8 kpc and this is a typical value irrespective of waveband and galaxy morphology, concentration, and asymmetry. Distribution and typical trends of scale lengths have also been derived in all the other SDSS bands with linear relations presented to accurately transform a typical scale length in one waveband to another. Such transformations could be useful input in numerical simulations of galaxy formation and evolution of the Hubble sequence.