MUSEQuBES: Probing Anisotropies in Gas and Metal Distributions in the Circumgalactic Medium

arXiv:2602.17593 · astro-ph.GA · Submitted 2026-08-17 · Read on arXiv

Sayak Dutta, Sowgat Muzahid, Joop Schaye, Sean Johnson, Edmund Christian Herenz, Ismael Pessa, Ramona Augustin, Nicolas F. Bouché, Joey Braspenning, Sebastiano Cantalupo, Sourav Das, Martin Wendt

astro-ph.GA

Submitted: 2026-08-17

Updated: 2026-08-18

Comments: Submitted to ApJ. Comments are welcome

License: http://creativecommons.org/licenses/by/4.0/

The gist: We investigate the azimuthal dependence of H I and O VI-bearing gas in the circumgalactic medium (CGM) of 113 isolated galaxies in the redshift range 0.12 < z < 0.75, including 91 new measurements

Terminology

Abstract

We investigate the azimuthal dependence of H I and O VI-bearing gas in the circumgalactic medium (CGM) of 113 isolated galaxies in the redshift range 0.12 < z < 0.75, including 91 new measurements from the MUSE Quasar-fields Blind Emitters Survey (MUSEQuBES). The H I covering fraction (k HI) within the virial radius (Rvir) of low-mass (7 < log10(M*/Msun)< 9) galaxies, for a threshold column density of log10(N(HI)/cm-2) = 14.5, exhibits an enhancement along both the disk plane (azimuthal angle phi < 20 degree) and in the polar direction (phi > 70 degree). In contrast, such a bimodal distribution is not observed for higher mass galaxies (9 < log10(M*/Msun) < 11.3). Similarly, the O VI covering fraction (k OVI), for a threshold of log10(N(OVI)/cm-2) = 14.0, shows a tentative enhancement along both the projected major and minor axes for low-mass galaxies. In contrast, O VI-bearing gas around higher- mass galaxies appears more uniformly distributed, with no significant azimuthal dependence. Finally, using the halo circular-velocity-normalized pixel-velocity two-point correlation function (TPCF), we find that O VI absorbers are kinematically narrower along the disk plane compared to the polar directions of the host galaxies with similar stellar mass distributions. The observed isotropic distribution of O VI in high-mass halos suggests that its spatial distribution is governed by global halo properties; however, the O VI kinematics retain memory of the site of origin.

Sources

Related papers