Elmo Tempel, Antti Tamm, Rain Kipper, Peeter Tenjes
Is it realistic to recover the 3D structure of galaxies from their images? To answer this question, we generate a sample of idealised model galaxies consisting of a disc-like component and a spheroidal component (bulge) with varying luminosities, inclination angles and structural parameters, and component density following the Einasto distribution. We simulate these galaxies as if observed in the SDSS project through ugriz filters, thus gaining a set of images of galaxies with known intrinsic properties. We remodel the galaxies with a 3D galaxy modelling procedure and compare the restored parameters to the initial ones in order to determine the uncertainties of the models. Down to the r-band limiting magnitude 18, errors of the restored integral luminosities and colour indices remain within 0.05 mag and errors of the luminosities of individual components within 0.2 mag. Accuracy of the restored bulge-to-disc ratios (B/D) is within 40% in most cases, and becomes even worse for galaxies with low B/D due to difficulties in reconstructing their bulge properties. Nevertheless, the general balance between bulges and discs is not shifted systematically. Inclination angle estimates are better for disc-dominated galaxies, with the errors remaining below 5deg for galaxies with B/D < 2. Errors of the recovered sizes of the galactic components are less than 10% in most cases. Axial ratios and the parameter N of Einasto's distribution (similar to the S\'ersic index) are relatively inaccurate, but can provide statistical estimates for large samples. In general, models of disc components are more accurate than models of bulge components for geometrical reasons.
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http://arxiv.org/abs/1205.6319
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