Spectral modeling codes that estimate photometric redshifts (photo-z) are a powerful and often reliable method for determining redshifts of galaxies. However, there are notable instances where degeneracies in spectral energy distribution (SED) colors lead to `catastrophic' failures. We highlight the case of COSBO-7, a dusty, intermediate-z galaxy that masqueraded as a high-z source, because it demonstrates a unique scenario where photo-z codes run into issues despite extensive multi-wavelength photometry. We advocate that photo-z fitting should aim to: (1) use the entire available SED (UV--radio) whenever possible to help break color degeneracies, (2) allow flexible dust attenuation prescriptions, both in terms of the attenuation curve slope and a varying 2175{\AA} absorption feature, and (3) implement uncertainty floors to account for limitations in spectral models and also on the photometry itself.
@article{arxiv.2507.01251,
title = {Avoiding (photo-$z$) Catastrophe},
author = {A. J. Battisti and E. da Cunha and S. Jin and J. A. Hodge},
journal= {arXiv preprint arXiv:2507.01251},
year = {2025}
}
Comments
3 pages, 1 figure. Accepted for publication in RNAAS