ALMA visits the QSO MUSEUM: Connecting molecular gas and the cool circumgalactic medium around 37 z∼3 quasars

@misc{ritter2026alma,
  title = {{ALMA visits the QSO MUSEUM: Connecting molecular gas and the cool circumgalactic medium around 37 $z\sim3$ quasars}},
  author = {Jelena Ritter and Fabrizio Arrigoni Battaia and Bo Peng and Jay González Lobos and Chian-Chou Chen and Aura Obreja and Nahir Muñoz-Elgueta and Chiara Circosta},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2606.30742},
  eprint = {2606.30742},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2606.30742},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - ALMA visits the QSO MUSEUM: Connecting molecular gas and the cool circumgalactic medium around 37 z∼3 quasars
AU  - Jelena Ritter
AU  - Fabrizio Arrigoni Battaia
AU  - Bo Peng
AU  - Jay González Lobos
AU  - Chian-Chou Chen
AU  - Aura Obreja
AU  - Nahir Muñoz-Elgueta
AU  - Chiara Circosta
PY  - 2026
DA  - 2026/10/24
PB  - arXiv
DO  - 10.48550/arxiv.2606.30742
UR  - https://arxiv.org/abs/2606.30742
AB  - Extended Lyα emission is ubiquitous around quasars and traces the cool circumgalactic medium, providing insights into halo gas dynamics and active galactic nucleus feedback. However, its connection to the cold molecular gas of the host galaxies remains largely unexplored. We characterize the molecular gas reservoirs of quasars at z∼3 and investigate their connection to extended Lyα emission using ALMA CO(4-3) observations of 37 quasars from the QSO MUSEUM survey, previously mapped in Lyα with VLT/MUSE. We derive molecular gas masses and gas fractions, explore correlations with Lyα nebula and quasar properties, and search for CO-emitting companions. We detect 21/37 quasars in CO(4-3), with gas masses of M_gas≈(3−40) ×10^9 M_⊙. Quasars with the most massive molecular gas reservoirs are associated with the centrally dimmest Lyα nebulae, while those hosting the centrally brightest Lyα nebulae are generally not detected in CO. This suggests that gas and dust in the hosts regulate Lyα escape and consequently affect the emission from halo gas. We find evidence that lower-Eddington-ratio quasars harbor more massive gas reservoirs, while strongly accreting quasars (λ_Edd gtrapprox 0.9) likely deplete their gas; for example, through powerful quasar-driven outflows. Despite their higher molecular gas masses within the sample, CO-detected low-Eddington quasars exhibit low gas fractions with a median M_gas/M_* ∼ 0.10, below what is typically found for inactive star-forming galaxies. Six quasars are marginally resolved in CO, with effective radii up to ∼ 8 kpc. In addition, we detect 14 high-fidelity companion galaxies, indicating overdense quasar environments with a quasar-galaxy cross-correlation length of 9.81^+2.22_−2.05 h^−1cMpc.
ER  -