Avoiding (photo-z) Catastrophe
Abstract
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 absorption feature, and (3) implement uncertainty floors to account for limitations in spectral models and also on the photometry itself.
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