28th of June 2016 |
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Non-parametric estimation of morphological lopsidedness |
by Nadine Giese (University of Groningen) |
Upcoming blind HI surveys with e.g. APERTIF
or ASKAP will provide data for tens of thousands of galaxies that can be used
for a detailed study
of galaxy evolution. Due to the large number of expected sources and the
limited resolution of the majority of objects, detailed modelling is not
feasible for most detections. The use of non-parametric methods for the
classification of objects is a promising alternative because they are
fast and objective. Unfortunately they suffer from effects caused by low
signal-to-noise, limited resolution as well as the intrinsic orientation
of the studied objects. We investigated the limitations of existing
non-parametric methods and present a possible method for the correction
of the effects of signal-to-noise. The figure clearly shows for two sets of model galaxies how well the signal-to-noise correction works on the Asymmetry parameter (lower panels, to be compared to the upper panels with uncorrected asymmetries) even for many of the the low signal-to-noise (blue) objects. Reference: N. Giese, T. van der Hulst, P. Serra, T. Oosterloo, accepted for publication in MNRAS. Image Credit: WSRT, ASTRON |