Galaxy Zoo: Quantitative Visual Morphological Classifications for 48,000 galaxies from CANDELS
Abstract
We present quantified visual morphologies of approximately 48,000 galaxies observed in three Hubble Space Telescope legacy fields by the Cosmic And Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and classified by participants in the Galaxy Zoo project. 90% of galaxies have z < 3 and are observed in rest-frame optical wavelengths by CANDELS. Each galaxy received an average of 40 independent classifications, which we combine into detailed morphological information on galaxy features such as clumpiness, bar instabilities, spiral structure, and merger and tidal signatures. We apply a consensus-based classifier weighting method that preserves classifier independence while effectively down-weighting significantly outlying classifications. After analysing the effect of varying image depth on reported classifications, we also provide depth-corrected classifications which both preserve the information in the deepest observations and also enable the use of classifications at comparable depths across the full survey. Comparing the Galaxy Zoo classifications to previous classifications of the same galaxies shows very good agreement; for some applications the high number of independent classifications provided by Galaxy Zoo provides an advantage in selecting galaxies with a particular morphological profile, while in others the combination of Galaxy Zoo with other classifications is a more promising approach than using any one method alone. We combine the Galaxy Zoo classifications of "smooth" galaxies with parametric morphologies to select a sample of featureless disks at 1 < z < 3, which may represent a dynamically warmer progenitor population to the settled disk galaxies seen at later epochs.
Keywords
Cite
@article{arxiv.1610.03070,
title = {Galaxy Zoo: Quantitative Visual Morphological Classifications for 48,000 galaxies from CANDELS},
author = {B. D. Simmons and Chris Lintott and Kyle W. Willett and Karen L. Masters and Jeyhan S. Kartaltepe and Boris Häußler and Sugata Kaviraj and Coleman Krawczyk and S. J. Kruk and Daniel H. McIntosh and R. J. Smethurst and Robert C. Nichol and Claudia Scarlata and Kevin Schawinski and Christopher J. Conselice and Omar Almaini and Henry C. Ferguson and Lucy Fortson and William Hartley and Dale Kocevski and Anton M. Koekemoer and Alice Mortlock and Jeffrey A. Newman and Steven P. Bamford and N. A. Grogin and Ray A. Lucas and Nimish P. Hathi and Elizabeth McGrath and Michael Peth and Janine Pforr and Zachary Rizer and Stijn Wuyts and Guillermo Barro and Eric F. Bell and Marco Castellano and Tomas Dahlen and Avishai Dekel Jamie Ownsworth and Sandra M. Faber and Steven L. Finkelstein and Adriano Fontana and Audrey Galametz and Ruth Grützbauch and David Koo and Jennifer Lotz and Bahram Mobasher and Mark Mozena and Mara Salvato and Tommy Wiklind},
journal= {arXiv preprint arXiv:1610.03070},
year = {2016}
}
Comments
30 pages, 14 figures, MNRAS accepted. Galaxy classifications available at data.galaxyzoo.org