Uncertainty-aware blob detection with an application to integrated-light stellar population recoveries

Parzer, Fabian; Jethwa, Prashin; Boecker, Alina; Alfaro-Cuello, Mayte; Scherzer, Otmar; van de Ven, Glenn
Referencia bibliográfica

Astronomy and Astrophysics

Fecha de publicación:
6
2023
Número de autores
6
Número de autores del IAC
1
Número de citas
1
Número de citas referidas
1
Descripción
Context. Blob detection is a common problem in astronomy. One example is in stellar population modelling, where the distribution of stellar ages and metallicities in a galaxy is inferred from observations. In this context, blobs may correspond to stars born in situ versus those accreted from satellites, and the task of blob detection is to disentangle these components. A difficulty arises when the distributions come with significant uncertainties, as is the case for stellar population recoveries inferred from modelling spectra of unresolved stellar systems. There is currently no satisfactory method for blob detection with uncertainties.
Aims: We introduce a method for uncertainty-aware blob detection developed in the context of stellar population modelling of integrated-light spectra of stellar systems.
Methods: We developed a theory and computational tools for an uncertainty-aware version of the classic Laplacian-of-Gaussians method for blob detection, which we call ULoG. This identifies significant blobs considering a variety of scales. As a prerequisite to apply ULoG to stellar population modelling, we introduced a method for efficient computation of uncertainties for spectral modelling. This method is based on the truncated Singular Value Decomposition and Markov chain Monte Carlo sampling (SVD-MCMC).
Results: We applied the methods to data of the star cluster M 54. We show that the SVD-MCMC inferences match those from standard MCMC, but they are a factor 5-10 faster to compute. We apply ULoG to the inferred M 54 age/metallicity distributions, identifying between two or three significant, distinct populations amongst its stars.
Proyectos relacionados
Miembros del grupo
Huellas de la Formación de las Galaxias: Poblaciones estelares, Dinámica y Morfología
Bienvenida a la página web del g rupo de investigación Traces of Galaxy Formation. Somos un grupo de investigación amplio, diverso y muy activo cuyo objetivo principal es entender la formación de galaxias en el Universo de una manera lo más completa posible. Con el estudio detellado de las poblaciones estelares como bandera, estamos constantemente
Ignacio
Martín Navarro