The PAU Survey: Uncovering the connection between intrinsic and observed galaxy properties using symbolic regression

Fuente: arXiv
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Main Authors: Kumar, Adarsh, Baugh, Carlton M., Koonkor, Suttikoon, Manzoni, Giorgio, Panda, Sukanta, Girones, D. Navarro, Casas, R., Carretero, J., Castander, F., De Vicente, J., Bellido, J. Garcia, Gaztanaga, E., Miquel, R., Renard, P., Crespi, P. Tallada
Format: Preprint
Published: 2025
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author Kumar, Adarsh
Baugh, Carlton M.
Koonkor, Suttikoon
Manzoni, Giorgio
Panda, Sukanta
Girones, D. Navarro
Casas, R.
Carretero, J.
Castander, F.
De Vicente, J.
Bellido, J. Garcia
Gaztanaga, E.
Miquel, R.
Renard, P.
Crespi, P. Tallada
author_facet Kumar, Adarsh
Baugh, Carlton M.
Koonkor, Suttikoon
Manzoni, Giorgio
Panda, Sukanta
Girones, D. Navarro
Casas, R.
Carretero, J.
Castander, F.
De Vicente, J.
Bellido, J. Garcia
Gaztanaga, E.
Miquel, R.
Renard, P.
Crespi, P. Tallada
contents Estimating stellar masses for billions of galaxies in upcoming surveys requires methods that are both accurate and computationally efficient. We present a new approach using symbolic regression trained on a simulation to derive simple, explicit mathematical expressions that estimate galaxy stellar masses from basic observables: photometry and redshift. Using a mock catalogue from the GALFORM semi-analytical model that reproduces the Physics of the Accelerating Universe Survey (PAUS), we show that a linear combination of just four observables -- minimally processed $u$- and $i$- band magnitudes, observed $(g-r)$ colour, and redshift -- can recover stellar masses with accuracy comparable to traditional spectral energy distribution (SED) fitting, but with negligible computational cost. Our expressions can be evaluated instantaneously for millions of galaxies, making them ideal for next-generation surveys like LSST and Euclid. When observational errors are included, symbolic regression achieves a similar accuracy to deep neural networks while maintaining transparency. Validation against CIGALE SED fitting on PAUS data shows agreement within 0.13 dex for galaxies with $M_{*} > 10^8 M_{\odot}$. We demonstrate that the stellar mass function can be recovered at $z < 0.5$, though with distortions at the extremes: the high-mass end is overestimated by a factor of $\sim 3$ at $10^{11.5} h^{-1} M_{\odot}$ due to scatter. Our approach offers a fast, transparent alternative to traditional methods without sacrificing accuracy for the bulk of the galaxy population.
format Preprint
id arxiv_https___arxiv_org_abs_2512_13389
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The PAU Survey: Uncovering the connection between intrinsic and observed galaxy properties using symbolic regression
Kumar, Adarsh
Baugh, Carlton M.
Koonkor, Suttikoon
Manzoni, Giorgio
Panda, Sukanta
Girones, D. Navarro
Casas, R.
Carretero, J.
Castander, F.
De Vicente, J.
Bellido, J. Garcia
Gaztanaga, E.
Miquel, R.
Renard, P.
Crespi, P. Tallada
Astrophysics of Galaxies
Estimating stellar masses for billions of galaxies in upcoming surveys requires methods that are both accurate and computationally efficient. We present a new approach using symbolic regression trained on a simulation to derive simple, explicit mathematical expressions that estimate galaxy stellar masses from basic observables: photometry and redshift. Using a mock catalogue from the GALFORM semi-analytical model that reproduces the Physics of the Accelerating Universe Survey (PAUS), we show that a linear combination of just four observables -- minimally processed $u$- and $i$- band magnitudes, observed $(g-r)$ colour, and redshift -- can recover stellar masses with accuracy comparable to traditional spectral energy distribution (SED) fitting, but with negligible computational cost. Our expressions can be evaluated instantaneously for millions of galaxies, making them ideal for next-generation surveys like LSST and Euclid. When observational errors are included, symbolic regression achieves a similar accuracy to deep neural networks while maintaining transparency. Validation against CIGALE SED fitting on PAUS data shows agreement within 0.13 dex for galaxies with $M_{*} > 10^8 M_{\odot}$. We demonstrate that the stellar mass function can be recovered at $z < 0.5$, though with distortions at the extremes: the high-mass end is overestimated by a factor of $\sim 3$ at $10^{11.5} h^{-1} M_{\odot}$ due to scatter. Our approach offers a fast, transparent alternative to traditional methods without sacrificing accuracy for the bulk of the galaxy population.
title The PAU Survey: Uncovering the connection between intrinsic and observed galaxy properties using symbolic regression
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2512.13389