zCluster is a package for measuring galaxy cluster photometric redshifts using data from large public surveys. It can also produce photometric redshift estimates and galaxy density maps for any point in the sky using the included zField tool.

• Documentation: https://zcluster.readthedocs.io
• License: GPL v3
• Authors: Matt Hilton, with contributions from Kabelo Kesebonye, Phumlani Phakathi, Denisha Pillay, and Damien Ragavan (not all reflected on GitHub).
• Installation: pip install zCluster
• Support: Please use the GitHub issues page, and/or contact Matt Hilton.

zCluster has built-in support for querying large photometric surveys - currently:

• SDSS (DR7 - DR12)
• SDSS Stripe 82 (from SDSS DR7)
• CFHTLenS
• PS1 (DR2)
• DECaLS (DR8 - DR10)
• DES (DR1, DR2 and Y3 internal)
• KiDS (DR4)

For details of the algorithm, its performance, and the output of the code, refer to Hilton et al. (2018), which presents results based on SDSS, S82, and CFHTLenS, and/or Hilton et al. (2021), which presents results based on DECaLS DR8. The other surveys listed above are work in progress (so use with caution; PS1 in particular is problematic). Pillay et al. (2021) presents the first use of the package for producing projected galaxy density maps.

If you find zCluster useful in your work, please cite whichever one of the above papers that you think is appropriate (together, of course, with the appropriate papers for the optical/IR survey used).

zCluster can also run on user-supplied .fits table photometric catalogs, provided that they have columns named ID, RADeg, decDeg, and magnitude column names in the form u_MAG_AUTO, u_MAGERR_AUTO etc..

zCluster is under active development, and not all documentation is up to date. The package also contains some experimental features that are not necessarily well tested.