An Optimal Multihump Filter for Photometric Redshifts

We propose a novel type of filter for multicolor imaging to improve on the photometric redshift estimation of galaxies. An extra filter—specific to a certain photometric system—may be utilized with high efficiency. We present a case study of the Hubble Space Telescope's Advanced Camera for Surveys and show that one extra exposure could cut down the mean square error on photometric redshifts by 34% over the z < 1.3 redshift range.