Galaxy Zoo 2: detailed morphological classifications for 304,122 galaxies from the Sloan Digital Sky Survey

By Kyle W. Willett, Chris J. Lintott, Steven Bamford, Karen L. Masters, B. Simmons, K. Casteels, E. Edmondson, L. Fortson, S. Kaviraj, William Keel and 19 more. 2013

525 citations recorded by the source corpus.

We present the data release for Galaxy Zoo 2 (GZ2), a citizen science project with more than 16 million morphological classifications of 304 122 galaxies drawn from the Sloan Digital Sky Survey (SDSS). Morphology is a powerful probe for quantifying a galaxy's dynamical history; however, automatic classifications of morphology (either by computer analysis of images or by using other physical parameters as proxies) still have drawbacks when compared to visual inspection. The large number of images available in current surveys makes visual inspection of each galaxy impractical for individual astronomers. GZ2 uses classifications from volunteer citizen scientists to measure morphologies for all galaxies in the DR7 Legacy survey with mr > 17, in addition to deeper images from SDSS Stripe 82. While the original GZ2 project identified galaxies as early-types, late-types or mergers, GZ2 measures finer morphological features. These include bars, bulges and the shapes of edge-on disks, as well as quantifying the relative strengths of galactic bulges and spiral arms. This paper presents the full public data release for the project, including measures of accuracy and bias. The majority (≳90 per cent) of GZ2 classifications agree with those made by professional astronomers, especially for morphological T-types, strong bars and arm curvature. Both the raw and reduced data products can be obtained in electronic format at http://data.galaxyzoo.org.

Subfields: Astronomy and Astrophysics, Ecological Modeling, Ecology

View Paper: https://www.semanticscholar.org/paper/4b02840d09d50ec2fdae89b4a71acf394b1a2581

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Citations in the corpus

A catalogue of 2D photometric decompositions in the SDSS-DR7 spectroscopic main galaxy sample: preferred models and systematics (2014, methodology): “Section 7.3 discusses possible effects of bars on the fitting based on barred galaxies identified in GZ2.”
Rotation-invariant convolutional neural networks for galaxy morphology prediction (2015, methodology): “Comparisons of Galaxy Zoo morphologies to smaller samples from both experts and automated classifications show high levels of agreement, testifying to the accuracy of the crowdsourced annotations (Bamford et al. 2009; Willett et al. 2013).”
Exploiting Cyclic Symmetry in Convolutional Neural Networks (2016, methodology): “The images display galaxies with various morphological properties and form a subset of the image used in the Galaxy Zoo 2 project (Willett et al., 2013).”
Dawes Review 4: Spiral Structures in Disc Galaxies (2014, methodology): “According to the Galaxy Zoo project, spiral galaxies make up about two thirds of all massive galaxies, whilst around one third are ellipticals, and a few per cent merging galaxies (Lintott et al. 2011; Willett et al. 2013).”
THE TENTH DATA RELEASE OF THE SLOAN DIGITAL SKY SURVEY: FIRST SPECTROSCOPIC DATA FROM THE SDSS-III APACHE POINT OBSERVATORY GALACTIC EVOLUTION EXPERIMENT (2013, methodology): “New in DR10 are morphological classifications of SDSS images of galaxies by 200,000 citizen scientists via the Galaxy Zoo project (Lintott et al. 2008, 2011; Willett et al. 2013).”
The ATLAS3D project - XXIX. The new look of early-type galaxies and surrounding fields disclosed by extremely deep optical images (2014, background): “The Galaxy zoo project has pioneered the eye classification of large numbers of galaxies with equally large numbers of volunteers filling web–based polls (Lintott et al. 2008; Willett et al. 2013).”
The Fifteenth Data Release of the Sloan Digital Sky Surveys: First Release of MaNGA-derived Quantities, Data Visualization Tools, and Stellar Library (2018, methodology): “For a simple conversion between Galaxy Zoo classifications and modern (bulge-sized based) Ttypes see details in Willett et al. (2013), which also includes general advice on how to best use Galaxy Zoo classifications for science.”
Principal Component Analysis (2018, methodology): “In astronomy, we considered data from galaxies [Willett et al. 2013]; more specifically, a table that comprises features of spectroscopic redshifts for the galaxies.”
CALIFA : a diameter-selected sample for an integral field spectroscopy galaxy survey (2014, unknown): “When looking through the morphological classifications available from public databases we found that these were incomplete for our sample (e.g. Galaxy Zoo 2, 535 matches Willett et al. 2013) or missing a consistent classification in Hubble subtypes (NED).”