Simulation-Based Inference for Probabilistic Galaxy Detection and Deblending

Fuente: arXiv
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Autores principales: Mendoza, Ismael, Hansen, Derek, Liu, Runjing, Zhao, Zhe, Pang, Ziteng, Guinot, Axel, Avestruz, Camille, Regier, Jeffrey, Collaboration, the LSST Dark Energy Science
Formato: Preprint
Publicado: 2026
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author Mendoza, Ismael
Hansen, Derek
Liu, Runjing
Zhao, Zhe
Pang, Ziteng
Guinot, Axel
Avestruz, Camille
Regier, Jeffrey
Collaboration, the LSST Dark Energy Science
author_facet Mendoza, Ismael
Hansen, Derek
Liu, Runjing
Zhao, Zhe
Pang, Ziteng
Guinot, Axel
Avestruz, Camille
Regier, Jeffrey
Collaboration, the LSST Dark Energy Science
contents Stage-IV dark energy wide-field surveys, such as the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), will observe an unprecedented number density of galaxies. As a result, the majority of imaged galaxies will visually overlap, a phenomenon known as blending. Blending is expected to be a leading source of systematic error in astronomical measurements. To mitigate this systematic, we propose a new probabilistic method for detecting, deblending, and measuring the properties of galaxies, called the Bayesian Light Source Separator (BLISS). Given an astronomical survey image, BLISS uses convolutional neural networks to produce a probabilistic astronomical catalog by approximating the posterior distribution over the number of light sources, their centroids' locations, and their types (galaxy vs. star). BLISS additionally includes a denoising autoencoder to reconstruct unblended galaxy profiles. As a first step towards demonstrating the feasibility of BLISS for cosmological applications, we apply our method to simulated single-band images whose properties are representative of year-10 LSST coadds. First, we study each BLISS component independently and examine its probabilistic output as a function of SNR and degree of blending. Then, by propagating the probabilistic detections from BLISS to its deblender, we produce per-object flux posteriors. Using these posteriors yields a substantial improvement in aperture flux residuals relative to deterministic detections alone, particularly for highly blended and faint objects. These results highlight the potential of BLISS as a scalable, uncertainty-aware tool for mitigating blending-induced systematics in next-generation cosmological surveys.
format Preprint
id arxiv_https___arxiv_org_abs_2601_03422
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Simulation-Based Inference for Probabilistic Galaxy Detection and Deblending
Mendoza, Ismael
Hansen, Derek
Liu, Runjing
Zhao, Zhe
Pang, Ziteng
Guinot, Axel
Avestruz, Camille
Regier, Jeffrey
Collaboration, the LSST Dark Energy Science
Instrumentation and Methods for Astrophysics
Cosmology and Nongalactic Astrophysics
Stage-IV dark energy wide-field surveys, such as the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), will observe an unprecedented number density of galaxies. As a result, the majority of imaged galaxies will visually overlap, a phenomenon known as blending. Blending is expected to be a leading source of systematic error in astronomical measurements. To mitigate this systematic, we propose a new probabilistic method for detecting, deblending, and measuring the properties of galaxies, called the Bayesian Light Source Separator (BLISS). Given an astronomical survey image, BLISS uses convolutional neural networks to produce a probabilistic astronomical catalog by approximating the posterior distribution over the number of light sources, their centroids' locations, and their types (galaxy vs. star). BLISS additionally includes a denoising autoencoder to reconstruct unblended galaxy profiles. As a first step towards demonstrating the feasibility of BLISS for cosmological applications, we apply our method to simulated single-band images whose properties are representative of year-10 LSST coadds. First, we study each BLISS component independently and examine its probabilistic output as a function of SNR and degree of blending. Then, by propagating the probabilistic detections from BLISS to its deblender, we produce per-object flux posteriors. Using these posteriors yields a substantial improvement in aperture flux residuals relative to deterministic detections alone, particularly for highly blended and faint objects. These results highlight the potential of BLISS as a scalable, uncertainty-aware tool for mitigating blending-induced systematics in next-generation cosmological surveys.
title Simulation-Based Inference for Probabilistic Galaxy Detection and Deblending
topic Instrumentation and Methods for Astrophysics
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2601.03422