The miniJPAS survey: Maximising the photo- z accuracy from multi-survey datasets with probability conflation

• Published in: Astronomy and astrophysics (Berlin) 2024-04, Vol.684, p.A61
• Main Authors: Hernán-Caballero, A., Akhlaghi, M., López-Sanjuan, C., Vázquez Ramió, H., Laur, J., Varela, J., Civera, T., Muniesa, D., Finoguenov, A., Fernández-Ontiveros, J. A., Domínguez Sánchez, H., Chaves-Montero, J., Fernández-Soto, A., Lumbreras-Calle, A., Díaz-García, L. A., del Pino, A., González Delgado, R. M., Hernández-Monteagudo, C., Coelho, P., Jiménez-Teja, Y., Lopes, P. A. A., Marra, V., Tempel, E., Vílchez, J. M., Abramo, R., Alcaniz, J., Benítez, N., Bonoli, S., Carneiro, S., Cenarro, J., Cristóbal-Hornillos, D., Dupke, R., Ederoclite, A., Marín-Franch, A., Mendes de Oliveira, C., Moles, M., Sodré, L., Taylor, K.
• Format: Article
• Language: English
• Subjects: Accuracy; Errors; Galaxies; Modularity; Outliers (statistics); Photometry; Red shift
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361/202348513

We present a new method for obtaining photometric redshifts (photo- z ) for sources observed by multiple photometric surveys using a combination (conflation) of the redshift probability distributions (PDZs) obtained independently from each survey. The conflation of the PDZs has several advantages over the usual method of modelling all the photometry together, including the modularity, speed, and accuracy of the results. Using a sample of galaxies with narrow-band photometry in 56 bands from J-PAS and deeper grίzy photometry from the Hyper-SuprimeCam Subaru Strategic program (HSC-SSP), we show that PDZ conflation significantly improves photo- z accuracy compared to fitting all the photometry or using a weighted average of point estimates. The improvement over J-PAS alone is particularly strong for i ≳22 sources, which have low signal-to-noise ratios in the J-PAS bands. For the entire i