Extreme Emission-Line Galaxies in the MUSE Hubble Ultra Deep Field Survey

TL;DR

This study identifies and analyzes extreme emission-line galaxies in the Hubble Ultra Deep Field using MUSE data, revealing their properties, structures, and similarities to high-redshift galaxies, thus providing insights into galaxy evolution.

Contribution

The paper introduces a novel methodology for selecting EELGs from integral field spectroscopy data and characterizes their physical and kinematic properties in unprecedented depth.

Findings

Over half of the EELGs are spatially resolved.

Most EELGs do not show rotation patterns.

EELGs follow the same mass-metallicity relation as high-redshift galaxies.

Abstract

We apply a methodology to build a sample of extreme emission line galaxies (EELGs) using integral field spectroscopy data. In this work we follow the spectroscopic criteria corresponding for EELG selection and use the MUSE Hubble Ultra-Deep field survey, which includes the deepest spectroscopic survey ever performed. Objects in the primary (extended) sample were detected requiring a rest-frame equivalent width EWo $\geqslant$ 300A (200A $\leq$ EWo $\leq$ 300A) in any of the emission lines of [OII]$\lambda\lambda$3726,29, [OIII]$\lambda\lambda$5007,4959, or H$\alpha$. A detailed closer inspection of the spectra of the candidates selected has been performed on a one by one basis, in order to confirm their classification. For this sample, the line fluxes, physical properties and chemical abundances of the EELGs have been derived as well as their spatially resolved structure and kinematics. Four (five) of the galaxies in the primary (extended) sample, $\sim$57$\%$ ($\sim$83$\%$), were spatially resolved. Three (none) of them present a clear pattern compatible with rotation. We have shown how our entire EELGs sample share the same loci defined by high-redshift galaxies (z $\approx$ 6-8) for the mass-metallicity relation, illustrating their role as local analogs.