GLEAM: Galaxy Line Emission & Absorption Modeling

TL;DR

GLEAM is an open-source Python tool designed for automated, batch processing of galaxy spectra to fit emission and absorption lines, enabling efficient analysis across diverse datasets with minimal human intervention.

Contribution

GLEAM introduces a flexible, multiprocessing-capable Python package for uniform spectral line fitting, emphasizing reproducibility and ease of use in large extragalactic spectral surveys.

Findings

Successfully tested on large optical/infra-red spectroscopic datasets

Produces detailed measurements and visualizations of spectral lines

Supports diverse instrument setups and signal-to-noise conditions

Abstract

We present GLEAM (Galaxy Line Emission & Absorption Modeling), a Python tool for fitting Gaussian models to emission and absorption lines in large samples of 1D extragalactic spectra. GLEAM is tailored to work well in batch mode without much human interaction. With GLEAM, users can uniformly process a variety of spectra, including galaxies and active galactic nuclei, in a wide range of instrument setups and signal-to-noise regimes. GLEAM also takes advantage of multiprocessing capabilities to process spectra in parallel. With the goal of enabling reproducible workflows for its users, GLEAM employs a small number of input files, including a central, user-friendly configuration in which fitting constraints can be defined for groups of spectra and overrides can be specified for edge cases. For each spectrum, GLEAM produces a table containing measurements and error bars for the detected spectral lines and continuum, and upper limits for non-detections. For visual inspection and publishing, GLEAM can also produce plots of the data with fitted lines overlaid. In the present paper, we describe GLEAM's main features, the necessary inputs, expected outputs, and some example applications, including thorough tests on a large sample of optical/infra-red multi-object spectroscopic observations and integral field spectroscopic data. gleam is developed as an open-source project hosted at https://github.com/multiwavelength/gleam and welcomes community contributions.