A COMPUTER-GENERATED VISUAL MORPHOLOGY CATALOG OF ∼3,000,000 SDSS GALAXIES

Abstract

ABSTRACT We have applied computer analysis to classify the broad morphological types of ∼3 · 106 Sloan Digital Sky Survey (SDSS) galaxies. For each galaxy, the catalog provides the DR8 object ID, the R.A., the decl., and the certainty for the automatic classification as either spiral or elliptical. The certainty of the classification allows us to control the accuracy of a subset of galaxies by sacrificing some of the least certain classifications. The accuracy of the catalog was tested using galaxies that were classified by the manually annotated Galaxy Zoo catalog. The results show that the catalog contains ∼900,000 spiral galaxies and ∼600,000 elliptical galaxies with classification certainty that has a statistical agreement rate of ∼98% with the Galaxy Zoo debiased “superclean” data set. The catalog also shows that objects assigned by the SDSS pipeline with a relatively high redshift (z > 0.4) can have clear visual spiral morphology. The catalog can be downloaded at http://vfacstaff.ltu.edu/lshamir/data/morph_catalog. The image analysis software that was used to create the catalog is also publicly available.