Galaxy Zoo 1 data release

The original Galaxy Zoo project ran from July 2007 until February 2009. It was replaced by Galaxy Zoo 2, Galaxy Zoo: Hubble, and Galaxy Zoo: CANDELS. In the original Galaxy Zoo project, volunteers classified images of Sloan Digital Sky Survey galaxies as belonging to one of six categories - elliptical, clockwise spiral, anticlockwise spiral, edge-on , star/don't know, or merger.

Full catalog

This webpage allows anyone to download the resulting GZ classifications of nearly 900,000 galaxies in the project.

Galaxy Zoo is described in Lintott et al. 2008, MNRAS, 389, 1179 and the data release is described in Lintott et al. 2011, 410, 166. Anyone making use of the data should cite at least one of these papers in any resulting publications.

CASjobs

These tables are also accessible via CasJobs. Their names are:

• Table 2: DR10.zooSpec
  
• Table 3: DR10.zooNoSpec
  
• Table 4: DR10.zooConfidence
  
• Table 5: DR10.zooMirrorBias
  
• Table 6: DR10.zooMonochrome
  
• Table 7: DR10.zooVotes
  

AGN host galaxies

This sample is presented in the Galaxy Zoo 1 paper on AGN host galaxies (Schawinski et al., 2010, ApJ, 711, 284). It is a volume-limited sample of galaxies (0.02 < z < 0.05, M_z < –19.5 AB) with emission line classifications, stellar masses, velocity dispersions and GZ1 morphological classifications. When using this sample, please cite Schawinski et al. (2010) and Lintott et al. (2008, 2011).

Download here: schawinski_GZ_2010_catalogue.fits.gz

Overlapping Galaxy Pairs

This section contains data from the Galaxy Zoo survey for overlapping galaxy pairs, useful for studies of dust absorption. Data is derived from the Zoo 1 and Zoo 2 periods (August 2007–April 2010), and is described in detail by Keel et al. (PASP, 2013, 125, 923). The catalog contains a total of 1990 galaxy pairs.

There is a similar file of candidate pairs which were rejected for the final list because of evidence for interaction, other geometric reasons, or for having redshifts the wrong way around for dust backlighting.

The various overlapping galaxy pair types are illustrated in Figures 2a and 2b from Keel et al. 2013. Below are PDF files containing a single page for each galaxy pair, plus finding charts, more detailed photometry and identifications, and in some cases more precise redshifts. The PDFs are also available at http://astronomy.ua.edu/keel/observe/PDFcharts.

Merging galaxies

This sample of merging galaxies is assembled from SDSS Galaxy Zoo 1 data. It is a homogenous sample of galaxies (0.005 < z < 0.1) with spectroscopy for at least one of two merging galaxies in the pair. Value-added GZ data includes the morphologies of the merging galaxies as well as the relative stage of the merger. For any use of data from this sample, please cite Darg et al. (2010a) and Darg et al. (2010b).

Green peas

"Green peas" are compact galaxies with extremely high star-formation rates. Their name comes from their appearance in colour SDSS images, which is due to strong [OIII] λ5007 emission that appears in the r-band filter for large numbers of low-redshift (0.112 < z < 0.360) galaxies. Properties of the initial sample are described in Cardamone et al. (2009). Data below is from Table 4 in Cardamone et al. (2009).

Red Spirals

"Red Spirals" are galaxies with clearly identified spiral structure which are optically red in colour. Most spiral galaxies are blue in colour, while most ellipticals are red, so this sample of red spirals is an interesting intermediate population. The properties of a sample of disky red spirals are described in Masters et al. (2010), and compared to a match sample of normal blue spirals. The data below is from Appendix A, Tables A1 and A2 in Masters et al. (2010) and gives the red and blue spiral samples from that work.

Galaxy Zoo 2

Galaxy Zoo 2 (GZ2) was the successor project to Galaxy Zoo. GZ2 extends the original Galaxy Zoo classifications for a subsample of the brightest and largest galaxies in the Legacy release, measuring more detailed morphological features. This includes galactic bars, spiral arm and pitch angle, bulges, edge-on galaxies, relative ellipticities, and many others. Two debiased Galaxy Zoo tables are provided, described in Willett et al. (2013) and Hart et al. (2016): we strongly advise the use of the Hart et al. (2016) table, as this debiases the GZ2 quetion tree most consistently.

Full Catalog

These tables provide the GZ2 classifications for nearly 300,000 galaxies in the SDSS.

The project description and data reduction is in Willett et al. 2013, MNRAS, 435, 2835 — please cite this paper if making any use of the GZ2 data. The table numbers below are the same as their order in the paper.

The code used to reduce GZ2 is available on GitHub — please take a look either at its webpage or fork it from the repository if you're interested in the details.

CASjobs

The GZ2 catalog is also accessible via CasJobs in Data Release 10. The table names in CasJobs are:

• Table 5: DR10.zoo2MainSpecz
  
• Table 6: DR10.zoo2MainPhotoz
  
• Table 7: DR10.zoo2Stripe82Normal
  
• Table 8: DR10.zoo2Stripe82Coadd1
  
• Table 9: DR10.zoo2Stripe82Coadd2
  

SDSS Skyserver

For any object in SDSS DR10, you can access its Galaxy Zoo or Galaxy Zoo 2 classifications (if present) by using the "Explore" tool. Just click the "Galaxy Zoo" link under "Imaging Summary" in the left-hand sidebar (example here).

Images

The GZ2 images are available for download on Zenodo.

Bar lengths

In conjunction with Galaxy Zoo 2, we ran a parallel project to measure lengths, widths, and angles of galactic bars using an interactive interface. See Hoyle et al. (2011) for a description of the project and scientific results. The full set of results can be downloaded below.

Dust-lane spheroidal galaxies

Early Galaxy Zoo 2 classifications were used to identify a sample of 362 spheroidal galaxies with prominent dust lanes (DLSGs), ranging from redshifts of z=0.01 to 0.07. Catalogues of the galaxy properties, along with multi-wavelength coverage from radio through ultraviolet, are available here.

All tables below are in ASCII format.

• Basic information
• Radio-wavelength data from FIRST
• Infrared photometry from IRAS
• Optical photometry from SDSS
• Optical spectroscopy from SDSS
• UV photometry from GALEX

Please cite the DLSG (Kaviraj et al. 2012; Shabala et al. 2012; Kaviraj et al. 2013) and Galaxy Zoo 2 (Willett et al. 2013) publications if using this data.

Galaxy Zoo: Hubble

Galaxy Zoo: Hubble used data from the Hubble Space Telescope to classify images of distant galaxies beyond the reach of SDSS. Images for GZH were taken from the Advanced Camera for Surveys (ACS) aboard Hubble, including data from multiple Legacy surveys.

Full catalog

The full reduction and analysis of GZ: Hubble was published in Willett et al. (2017) (available both from arXiv or the MNRAS journal). Please cite this paper if using any data from the project. The full data reduction pipeline and analysis codes for GZH are available as an open-source Github repository.

Bar fraction evolution

Melvin et al. (2014) used GZ2 and preliminary GZ: Hubble data to study the evolution of the bar fraction in galaxies over cosmic timescales. Presented here are links to webpages with the HST postage stamp images for the different galaxy samples.

• GZ: Hubble disk galaxy sample split into three stellar mass bins:
  • Low mass sample (10.0≤log(Mstar)<10.34; N=789)
  • Intermediate mass sample (10.34≤log(Mstar)<10.64; N=801)
  • High mass sample (log(Mstar)≥10.64; N=790)
• GZ: Hubble barred disk galaxy sample (N=317)
• Disk galaxies with Tphot≤2.0 (N=98)

Shown here is a diagram of the classification scheme and decision tree used in GZ: Hubble.

Galaxy Zoo: CANDELS

Galaxy Zoo: CANDELS classified the morphology of galaxies in images from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). CANDELS images were taken with both the ACS and WFC3 cameras on the Hubble Space Telescope, focusing on rest-frame optical wavelengths of galaxies at redshifts of 1 < z < 3.

Simmons et al. (2017) (available both from arXiv or the MNRAS journal) describes the project and data release. Please cite this paper if using any data from Galaxy Zoo: CANDELS.

Full catalog

Galaxy Zoo DECaLS

Galaxy Zoo DECaLS has now been superceded by Galaxy Zoo DESI. GZ DESI extends the Galaxy Zoo DECaLS morphological classifications to the full DESI footprint (instead of just the intersection of SDSS and DECaLS), increasing sky coverage by a factor of four.

New research projects should use the Galaxy Zoo DESI catalogues, available in the next section. The text below is left for reference.

Galaxy Zoo DECaLS classified the morphology of galaxies in images from the Dark Energy Camera Legacy Survey (DECaLS). DECaLS images were taken with the Dark Energy Camera (DECam) on the Blanco 4m telescope, located at the Cerro Tololo Inter-American Observatory. Deeper DECaLS images (r=23.6 versus r=22.2 from SDSS) reveal spiral arms, weak bars, and tidal features not previously visible in SDSS imaging. We released classifications for 314,000 galaxies.

For the first time, we included automatic morphology predictions made using deep learning models. These models are trained on volunteer answers and predict posteriors for what a typical volunteer might say. When tested on galaxies where the volunteers are confident, they were 99% accurate on every question. Code and extensive documentation are available if you would like to extend these models or apply them to new problems.

Walmsley et al. (2021) (available free from the MNRAS journal) describes the project and current data release. Please cite this paper if using any data from Galaxy Zoo DECaLS.

Galaxy Zoo DESI (8.7M)

Galaxy Zoo DESI includes detailed morphology measurements for 8.67 million galaxies in the DESI Legacy Imaging Surveys (DECaLS, MzLS, and BASS, plus DES). These are automated measurements made by deep learning models trained on Galaxy Zoo volunteer votes. Extending our morphology measurements outside of the previously-released DECaLS/SDSS intersection increases our sky coverage by a factor of 4 (5,000 to 19,000 deg$^2$) and allows for full overlap with complementary surveys including ALFALFA and MaNGA.
Our models typically predict the fraction of volunteers selecting each answer to within 5-10\% for every answer to every GZ question. The models are trained on newly-collected votes for DESI-LS DR8 images as well as historical votes from GZ DECaLS. Code and extensive documentation are available if you would like to extend these models or apply them to new problems.

Walmsley et al. (2023) (available free from the MNRAS journal) describes the project and current data release. Please cite this paper if using any data from Galaxy Zoo DESI.

Galaxy Zoo: Mergers

See this page for full details and data for the separate Galaxy Zoo: Mergers project.

Galaxy Builder

Galaxy Builder made use of citizen science to create disc-bulge-bar-spiral photometric models of 198 spiral galaxies, selected using GZ2 and the NASA-Sloan Atlas. The project is further described in Lingard et al. (2020).

Data visualizations

For an interactive visualization of the decision trees for each of the Galaxy Zoo projects, please look at this tool created by Coleman Krawczyk (University of Portsmouth).

Galaxy Zoo Decision Trees