A MUSE Source-Blind Survey for Emission from the Circumgalactic Medium

TL;DR

This study uses archival MUSE data to conduct a source-blind, wide-redshift-range survey detecting emission from the circumgalactic medium, revealing complex structures and dynamics around galaxies from low to high redshift.

Contribution

It presents the first wide-redshift, source-blind survey of CGM emission lines using MUSE, identifying diverse CGM structures and their kinematic properties.

Findings

Detected extended emission structures associated with galaxies at various redshifts.

Revealed turbulent and chaotic velocity fields in the CGM compared to galaxy disks.

Identified large-scale coherent motions in interacting galaxy systems.

Abstract

The recent detection of optical emission lines from the circumgalactic medium (CGM) in combined, large samples of low-redshift, normal galaxy spectra hints at the potential to map the cool ($\sim$ 10$^4$ K) CGM in individual, representative galaxies. Using archival data from a forefront instrument (MUSE) on the VLT, we present a source-blind, wide-redshift-range ($z \sim 0-5)$ narrow-band imaging survey for CGM emission. Our detected, resolved emission line sources are cataloged and include a 30 kpc wide H$\alpha$ source likely tracing the CGM of a low-mass galaxy (stellar mass $\sim$ $10^{8.78\pm0.42}$ M$_\odot$) at $z=0.1723$, a 60 kpc wide Ly $\alpha$ structure associated with a galaxy at $z=3.9076$, and a 130 kpc ($\sim r_{\rm vir}$) wide [O II] feature revealing an interaction between a galaxy pair at $z=1.2480$. The H$\alpha$ velocity field for the low-mass galaxy suggests that the CGM is more chaotic or turbulent than the galaxy disk, while that for the interacting galaxies shows large-scale ($\sim 50$ kpc) coherent motions.