Galaxy Zoo: morphologies derived from visual inspection of galaxies from the Sloan Digital Sky Survey

By Chris J. Lintott, Kevin Schawinski, A. Slosar, K. Land, Steven Bamford, D. Thomas, M. Jordan Raddick, Robert Nichol, A. Szalay, Dan Andreescu and 2 more. 2008

1,357 citations recorded by the source corpus.

In order to understand the formation and subsequent evolution of galaxies one must first distinguish between the two main morphological classes of massive systems: spirals and early-type systems. This paper introduces a project, Galaxy Zoo, which provides visual morphological classifications for nearly one million galaxies, extracted from the Sloan Digital Sky Survey (SDSS). This achievement was made possible by inviting the general public to visually inspect and classify these galaxies via the internet. The project has obtained more than 4 × 107 individual classifications made by ∼105 participants. We discuss the motivation and strategy for this project, and detail how the classifications were performed and processed. We find that Galaxy Zoo results are consistent with those for subsets of SDSS galaxies classified by professional astronomers, thus demonstrating that our data provide a robust morphological catalogue. Obtaining morphologies by direct visual inspection avoids introducing biases associated with proxies for morphology such as colour, concentration or structural parameters. In addition, this catalogue can be used to directly compare SDSS morphologies with older data sets. The colour–magnitude diagrams for each morphological class are shown, and we illustrate how these distributions differ from those inferred using colour alone as a proxy for morphology.

Subfields: Astronomy and Astrophysics, Computer Vision and Pattern Recognition, Ecology

View Paper: https://www.semanticscholar.org/paper/a3efd6c06d508b5cbed902a5e8e88c8f12cb5f04

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Computer Vision and Pattern Recognition

In Ecology

Citations in the corpus

GALAXY ZOO: THE FUNDAMENTALLY DIFFERENT CO-EVOLUTION OF SUPERMASSIVE BLACK HOLES AND THEIR EARLY- AND LATE-TYPE HOST GALAXIES (2010, methodology): “Only with the involvement of over 200,000 citizen scientists in the Galaxy Zoo project (Lintott et al. 2008) have we been able to gather multiple independent visual classifications for the entire SDSS main galaxy sample that are comparable to those of professional astronomers.”
Competing or aiming to be average?: normification as a means of engaging digital volunteers (2014, background): “For example, GalaxyZoo [25] involves the rapid assessment and categorisation of photos of galaxies, while WhatsInvasive [15] involves the spotting and logging of invasive plant species.”
THE BULK OF THE BLACK HOLE GROWTH SINCE z ∼ 1 OCCURS IN A SECULAR UNIVERSE: NO MAJOR MERGER–AGN CONNECTION (2010, background): “The number of objects we are dealing with allows us to do so (∼1400 in total), and the image quality deserves a detailed case- 3 With the notable exception of the citizen-based Galaxy Zoo project (Lintott et al. 2008, http://www.galaxyzoo.org).”
TESS Eclipsing Binary Stars. I. Short-cadence Observations of 4584 Eclipsing Binaries in Sectors 1–26 (2021, methodology): “A total of 6699 EB candidates were identified via the Planet Hunters TESS (PHT) citizen science project (Eisner et al. 2021), which is hosted by the Zooniverse platform (Lintott et al. 2008, 2011).”
Environment and self-regulation in galaxy formation (2009, methodology): “We have extended this approach recently through the Galaxy Zoo project (Lintott et al. 2008), which uses several 10 000s of volunteers on the internet to classify galaxies through a web interface.”
Simulating galaxy formation with the IllustrisTNG model (2017, background): “…& Driver 2008; Baldry et al. 2012; Bernardi et al. 2013; D’Souza, Vegetti & Kauffmann 2015), extend in size from a fraction to tens of kilo-parsecs (Shen et al. 2003; Baldry et al. 2012), and span a diverse morphological mix (e.g. Lintott et al. 2008; Kelvin et al. 2012; Kartaltepe et al. 2015).”
Artificial Intelligence and Collective Intelligence (2014, methodology): “However, other platforms (e.g., Zooniverse (Lintott et al. 2008)) implement a 'push' model where the system decides which tasks to send to a worker.”
AINUR: Atlas of Images of NUclear Rings (2009, methodology): “We also included the nuclear ring in NGC 5020, a galaxy not imaged by HS T and dimmer thanBT = 12.5, that was brought to our attention by a discussion on the forum pages of the galaxy zoo project (Lintott et al. 2008).”
Flux- and volume-limited groups/clusters for the SDSS galaxies: catalogues and mass estimation (2014, neutral): “[49] morf zoo – morphology from the galaxy zoo project (Lintott et al., 2008): 0 – unclear, 1 – spiral, 2 – elliptical; 28.”
The green valley is a red herring: Galaxy Zoo reveals two evolutionary pathways towards quenching of star formation in early-and late-type galaxies (2014, methodology): “We use Galaxy Zoo 1 visual classifications of galaxy morphologies3 from the Galaxy Zoo citizen science project (Lintott et al. 2008, 2011).”
THE RISE AND FALL OF PASSIVE DISK GALAXIES: MORPHOLOGICAL EVOLUTION ALONG THE RED SEQUENCE REVEALED BY COSMOS (2009, methodology): “We should also note that “wiki-morphologies” of the kind pioneered by GZ (Lintott et al. 2008) are an alternative way to obtain visual morphologies for large samples.”
Galaxy formation theory (2010, methodology): “Applying this type of morphological classification to today’s large datasets is difficult, but has been achieved by utilizing “crowdsourcing” techniques (Lintott et al. 2008).”
Revisiting the Hubble sequence in the SDSS DR7 spectroscopic sample: a publicly available Bayesian automated classification (2010, background): “This job can be done on small samples but becomes an impossible task in very large surveys such as the SDSS, unless it is done through the aggregated efforts of hundreds of thousands of people over the course of many months as for the Galaxy Zoo project (Lintott et al. 2008, 2010).”
Galaxy Zoo: a sample of blue early-type galaxies at low redshift (2009, methodology): “As described in (Lintott et al. 2008), Galaxy Zoo enlists the help of members of the public to classify the spectroscopic galaxy sample from the Sloan Digital Sky Survey.”
Lyα EMISSION FROM GREEN PEAS: THE ROLE OF CIRCUMGALACTIC GAS DENSITY, COVERING, AND KINEMATICS (2015, background): “To systematically identify objects originally discovered by the Galaxy Zoo (Lintott et al. 2008), Cardamone et al. defined a color selection for objects with strong [O III] emission in the SDSS r-band.”
Galaxy Zoo 2: detailed morphological classifications for 304,122 galaxies from the Sloan Digital Sky Survey (2013, methodology): “The Galaxy Zoo project (Lintott et al. 2008) was launched in 2007 to provide morphological classifications for nearly one c© 2013 RAS ar X iv :1 30 8.”
Incentivizing exploration (2014, background): “Scientiﬁc organizations such as Galaxy Zoo for astronomy and eBird for Ornithology try to synthesize the activities of a large group of enthusi-asts to make scientiﬁc observations at a collective scale [Lintott et al. 2008; Shel-don et al. 2007].”
Environmental effects on satellite galaxies: the link between concentration, size and colour profile (2008, background): “The ones regarded as the most reliable are probably eyeball classification and bulge-to-total luminosity (B/T hereafter), which are not easily obtained for large samples of galaxies (but see Lintott et al. 2008).”
Galaxy Zoo: Passive Red Spirals . (2009, methodology): “The Galaxy Zoo project (Lintott et al. 2008) revealed the presence of a significant number of visually classified spiral galaxies which are redder than the blue cloud (between 16-28% of the total galaxy population depending on environment, Bamford et al. 2009).”
Galaxy pairs in the Sloan Digital Sky Survey – VIII. The observational properties of post-merger galaxies (2013, methodology): “The basic Galazy Zoo sample selection includes ∼ 900,000 galaxies from the SDSS DR6, as described by Lintott et al (2008).”