Galaxy Tagging: photometric redshift refinement and group richness enhancement
Abstract
We present a new scheme, , for refining the photometric redshift measurements of faint galaxies by probabilistically tagging them to observed galaxy groups constructed from a brighter, magnitude-limited spectroscopy survey. First, this method is tested on the DESI light-cone data constructed on the GALFORM galaxy formation model to tests its validity. We then apply it to the photometric observations of galaxies in the Kilo-Degree Imaging Survey (KiDS) over a 1 deg region centred at 15. This region contains Galaxy and Mass Assembly (GAMA) deep spectroscopic observations (i-band<22) and an accompanying group catalogue to r-band<19.8. We demonstrate that even with some trade-off in sample size, an order of magnitude improvement on the accuracy of photometric redshifts is achievable when using . This approach provides both refined photometric redshift measurements and group richness enhancement. In combination these products will hugely improve the scientific potential of both photometric and spectroscopic datasets. The software will be made publicly available at https://github.com/pkaf/galtag.git.
Keywords
Cite
@article{arxiv.1802.09009,
title = {Galaxy Tagging: photometric redshift refinement and group richness enhancement},
author = {P. R. Kafle and A. S. G. Robotham and S. P. Driver and S. Deeley and P. Norberg and M. J. Drinkwater and L. J. Davies},
journal= {arXiv preprint arXiv:1802.09009},
year = {2018}
}
Comments
Submitted version, comments welcome