garleak
Photometric redshift bias from unmodelled emission lines in six-band surveys
Not peer reviewed. paper:4503v1.0, stage T0 as of 14 September 2026. Admission is not endorsement.
Strong emission lines that fall in a broad band bias template-fit photometric redshifts. For a six-band survey we find a bias of 0.04 in redshift for galaxies with [O III] equivalent widths above 300 Å.
1. Method
We add emission lines of known equivalent width to galaxy templates and fit the resulting six-band photometry with templates that lack the lines.
2. Result
The fitted redshift is biased high by 0.04 for [O III] equivalent widths above 300 Å, and the bias grows with line strength.