Galaxy Zoo: Morphological classifications for 120 000 galaxies in HST legacy imaging

Willett, Kyle W.; Galloway, Melanie A.; Bamford, Steven P.; Lintott, Chris J.; Masters, Karen L.; Scarlata, Claudia; Simmons, B. D.; Beck, Melanie; Cardamone, Carolin N.; Cheung, Edmond; Edmondson, Edward M.; Fortson, Lucy F.; Griffith, Roger L.; H�u�ler, Boris; Han, Anna; Hart, Ross; Melvin, Thomas; Parrish, Michael; Schawinski, Kevin; Smethurst, Rebecca J.; Smith, Arfon M.

Abstract

© 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. We present the data release paper for the Galaxy Zoo: Hubble (GZH) project. This is the third phase in a large effort to measure reliable, detailed morphologies of galaxies by using crowdsourced visual classifications of colour-composite images. Images in GZH were selected from various publicly released Hubble Space Telescope legacy programmes conducted with the Advanced Camera for Surveys, with filters that probe the rest-frame optical emission from galaxies out to z ~ 1. The bulk of the sample is selected to have mI814W < 23.5, but goes as faint as mI814W < 26.8 for deep images combined over five epochs. The median redshift of the combined samples is 〈 z 〉 = 0.9 ± 0.6, with a tail extending out to z ≃ 4. The GZH morphological data include measurements of both bulge- and disc-dominated galaxies, details on spiral disc structure that relate to the Hubble type, bar identification, and numerous measurements of clump identification and geometry. This paper also describes a new method for calibrating morphologies for galaxies of different luminosities and at different redshifts by using artificially redshifted galaxy images as a baseline. The GZH catalogue contains both raw and calibrated morphological vote fractions for 119 849 galaxies, providing the largest data set to date suitable for large-scale studies of galaxy evolution out to z ~ 1.

Citation

Willett, K. W., Galloway, M. A., Bamford, S. P., Lintott, C. J., Masters, K. L., Scarlata, C., …Smith, A. M. (2017). Galaxy Zoo: Morphological classifications for 120 000 galaxies in HST legacy imaging. Monthly Notices of the Royal Astronomical Society, 464(4), 4176-4203. https://doi.org/10.1093/mnras/stw2568

• Journal Article Type: Article
• Acceptance Date: Oct 5, 2016
• Online Publication Date: Oct 8, 2016
• Publication Date: Feb 1, 2017
• Deposit Date: Jan 6, 2017
• Publicly Available Date: Jan 6, 2017
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 464
• Issue: 4
• Pages: 4176-4203
• DOI: https://doi.org/10.1093/mnras/stw2568
• Keywords: methods: data analysis ; catalogues ; galaxies: evolution ; galaxies: highredshift ; galaxies: structure
• Public URL: https://nottingham-repository.worktribe.com/output/837776
• Publisher URL: http://mnras.oxfordjournals.org/content/464/4/4176
• Contract Date: Jan 6, 2017