SAGUI: SED-based Segmentation of Multi-band Galaxy Images -- Application to JADES in GOODS-South

TL;DR

Sagui is a modular framework that extends spectro-spatial analysis to multi-band galaxy imaging, enabling detailed pixel-level characterization of complex structures and faint features in diverse galaxy morphologies.

Contribution

It introduces a novel two-stage pixel-level analysis method combining starlet decomposition and spectral similarity, applicable to multi-band imaging data, including faint low-surface-brightness components.

Findings

Successfully characterizes complex galaxy structures like clumps, bars, and interactions.

Effectively recovers faint, diffuse low-surface-brightness features.

Demonstrates applicability to diverse galaxy morphologies in JWST data.

Abstract

We present sagui, a modular framework for the analysis of multi-band imaging data in spatially resolved galaxies, with synergies to integral-field spectroscopy (IFS). Building on the spectro-spatial paradigm introduced by capivara for IFS data, sagui extends this approach to imaging datasets, enabling a coherent, pixel-level treatment of spatial and spectral information across multiple bands. The method follows a two-stage strategy: a starlet-based decomposition is first used to identify and mask spatial structures across multiple scales while suppressing noise, and a spectral-similarity analysis then partitions the image into coherent pixel groups that preserve spectral consistency. In addition to compact and high-contrast structures, the framework incorporates a dedicated statistical treatment, based on a copula transform, to identify and recover faint, diffuse low-surface-brightness components. We demonstrate the method across a diverse range of galaxy morphologies, highlighting its ability to characterize complex spatial structures, including clumps, bars, interacting systems, and low-surface-brightness features. As a case study, we apply it to eleven morphologically diverse galaxies from the James Webb Space Telescope Advanced Deep Extragalactic Survey in the GOODS--South field. sagui is released under an MIT license and is available at https://rafaelsdesouza.github.io/sagui/.