MUSEQuBES: Probing Anisotropies in Gas and Metal Distributions in the Circumgalactic Medium
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). Of these, measurements for 46 galaxies lie within the virial radius ( R vir ), including 36 non-face-on systems for which azimuthal angle ( ϕ ) measurements are robust. The H i covering fraction ( κ H I ) within R vir of low-mass (7 < log 10 ( M ⋆ / M ⊙ ) ≤ 9) galaxies, for a threshold column density of log 10 ( N ( H I ) / cm − 2 ) = 14.5 , exhibits an enhancement along both the disk plane ( ϕ ≲ 20°) and in the polar direction ( ϕ ≳ 70°). In contrast, such a bimodal distribution is not observed for higher mass galaxies (9 < log 10 ( M ⋆ / M ⊙ ) ≤ 11.3). Similarly, the O vi covering fraction ( κ O VI ), for a threshold of log 10 ( N ( O VI ) / 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.
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BibTeX
@article{dutta2026musequbes,
title = {{MUSEQuBES: Probing Anisotropies in Gas and Metal Distributions in the Circumgalactic Medium}},
author = {Sayak Dutta and Sowgat Muzahid and Joop Schaye and Sean Johnson and Edmund Christian Herenz and Ismael Pessa and Ramona Augustin and Nicolas Bouché and Joey Braspenning and Sebastiano Cantalupo and Sourav Das and Martin Wendt},
journal = {The Astrophysical Journal},
year = {2026},
month = aug,
doi = {10.3847/1538-4357/ae9544},
eprint = {2602.17593},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05855517v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - MUSEQuBES: Probing Anisotropies in Gas and Metal Distributions in the Circumgalactic Medium
AU - Sayak Dutta
AU - Sowgat Muzahid
AU - Joop Schaye
AU - Sean Johnson
AU - Edmund Christian Herenz
AU - Ismael Pessa
AU - Ramona Augustin
AU - Nicolas Bouché
AU - Joey Braspenning
AU - Sebastiano Cantalupo
AU - Sourav Das
AU - Martin Wendt
PY - 2026
DA - 2026/08/27
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/ae9544
UR - https://hal.science/hal-05855517v1
AB - 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). Of these, measurements for 46 galaxies lie within the virial radius ( R vir ), including 36 non-face-on systems for which azimuthal angle ( ϕ ) measurements are robust. The H i covering fraction ( κ H I ) within R vir of low-mass (7 < log 10 ( M ⋆ / M ⊙ ) ≤ 9) galaxies, for a threshold column density of log 10 ( N ( H I ) / cm − 2 ) = 14.5 , exhibits an enhancement along both the disk plane ( ϕ ≲ 20°) and in the polar direction ( ϕ ≳ 70°). In contrast, such a bimodal distribution is not observed for higher mass galaxies (9 < log 10 ( M ⋆ / M ⊙ ) ≤ 11.3). Similarly, the O vi covering fraction ( κ O VI ), for a threshold of log 10 ( N ( O VI ) / 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.
SN - 0004-637X
SN - 1538-4357
ER -