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arXiv · 1610.03068

Galaxy Zoo: Morphological Classifications for 120,000 Galaxies in HST Legacy Imaging

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

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 programs conducted with the Advanced Camera for Surveys, with filters that probe the rest-frame optical emission from galaxies out to $z \sim 1$. The bulk of the sample is selected to have $m_{I814W} < 23.5$,but goes as faint as $m_{I814W} < 26.8$ for deep images combined over 5 epochs. The median redshift of the combined samples is $z = 0.9 \pm 0.6$, with a tail extending out to $z \sim 4$. The GZH morphological data include measurements of both bulge- and disk-dominated galaxies, details on spiral disk 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 dataset to date suitable for large-scale studies of galaxy evolution out to $z \sim 1$.

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Kyle W. Willett, Melanie A. Galloway, Steven P. Bamford, Chris J. Lintott, Karen L. Masters, Claudia Scarlata, B. D. Simmons, Melanie Beck, Carolin N. Cardamone, Edmond Cheung, Edward M. Edmondson, Lucy F. Fortson, Roger L. Griffith, Boris Haeussler, Anna Han, Ross Hart, Thomas Melvin, Michael Parrish, Kevin Schawinski, R. J. Smethurst, Arfon M. Smith. 2016-10-10. Galaxy Zoo: Morphological Classifications for 120,000 Galaxies in HST Legacy Imaging. https://doi.org/10.1093/mnras/stw2568

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