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.
|This table gives classifications of galaxies which have spectra included in SDSS Data Release 7. The fraction of the vote in each of the six categories is given, along with debiased votes in elliptical and spiral categories and flags identifying systems as classified as spiral, elliptical or uncertain.|
|Note: the provided flags in Table 2 are there for the convenience of users who do not want to get into the details too much. These are based upon a vote fraction threshold of 0.8. However, there is a complication in the debiasing (described in Bamford et al. 2009). The classification bias depends on whether one uses the type likelihoods directly, or applies a threshold. The bias is worse if thresholds are used. We therefore applied bias corrections computed in consistent fashion. So, for the debiased type likelihoods we computed the bias correction based on the elliptical/spiral ratio using the likelihoods directly; for the type flags we debiased the raw type likelihoods using a correction based on the elliptical/spiral ratio determined after applying a 0.8 threshold, and then applied the same threshold to produce the flags. Therefore, the type flags do not correspond to simply applying a 0.8 threshold on the debiased type likelihoods, though for many galaxies these will agree.|
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, Mz < –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
|OBJID||SDSS DR7 object ID|
|RA, DEC||RA and dec in J2000.0|
|REDSHIFT||spectroscopic redshift from SDSS|
|GZ1_MORPHOLOGY||Galaxy Zoo 1 morphology according to the Land et al. (2008) "clean" criterion. This is an integer where 0 = indeterminate, 1 = early type, 3 = merger, 4 = late type|
|BPT_CLASS||Spectroscopic classification of galaxy based on emission lines ratios in the BPT diagram. 0 = no emission lines, 1 = star-forming, 2 = composite, 3 = Seyfert and 4 = LINER.|
|U,G,R,I,Z||SDSS model magnitudes. These are extinction-corrected but not k-corrected.|
|SIGMA, SIGMA_ERR||Stellar velocity dispersion (and error) measured using GANDALF|
|LOG_MSTELLAR||log of stellar mass [M_sun]|
|L_O3||Extinction-corrected [OIII] luminosity|
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.
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" 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).
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
population. The properties
of a sample of disky
red spirals are
described in Masters
al. (2010), and
compared to a match
sample of normal blue
spirals. The data
below is from Appendix
A1 and A2 in Masters
et al. (2010) and
gives the red and blue
spiral samples from
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.
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.
|Table 8 - Stripe 82, coadded-depth (set 1)
|Table 8 gives classifications of the first set of 19,765 galaxies classified in the coadded (runs 106 and 206) Stripe 82 images. Coadded images are made from combining between 47–55 individual exposures, resulting in better detection of fainter features and improved seeing. This set of images had no adjustments made to its background, which resulted in coloured background noise for some galaxies.|
|Column description and format|
|Table 9 - Stripe 82, coadded-depth (set 2)
|Table 9 gives classifications of the second set of 19,761 galaxies classified in the coadded (runs 106 and 206) Stripe 82 images. Coadded images are made from combining between 47–55 individual exposures, resulting in better detection of fainter features and improved seeing. This set of images applied a modest colour desaturation to de-emphasise background noise in the coadded data.|
|Column description and format|
|SDSS metadata for GZ2
|This table provides pre-matched sets of metadata for the Galaxy Zoo 2 samples taken from DR7. This includes coordinates, photometry, size, and redshifts (where present). For science cases, we encourage users to instead use the latest measurements from the latest data release.|
|Column description and format|
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.
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
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).
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.
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.
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.
|These tables contain useful metadata matched to the morphological data in Tables 4–9. This includes (where available) redshifts, magnitudes, angular sizes, automatically-measured morphological parameters, and additional flags from the parent surveys.|
|Single zipped file including column descriptions and FITS tables with metadata for all GZ: Hubble images|
|GZH main sample||CSV||FITS
|GZH GOODS, shallow-depth imaging||CSV||FITS
|GZH GOODS, full-depth imaging||CSV||FITS
|GZH SDSS, coadded imaging||CSV||FITS
|GZH SDSS, single-depth imaging||CSV||FITS
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).
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