2024/05/06 by Anand Menon, Menon, Anand, Chris Power +1
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics of Galaxies (astro-ph.GA) #Baryon #Content (measure theory) #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #Dark matter #FOS: Physical sciences #Galaxy #Halo #Physics #Redshift #Reionization #Star (game theory) #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2405.03211
published in arXiv (Cornell University) (Cornell University)
openalex publication_date 2024/05/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The baryon mass content of dark matter halos in the early Universe depends on global factors - e.g. ionising ultraviolet (UV) radiation background - and local factors - e.g. star formation efficiency and assembly history. We use a lightweight semi-analytical model to investigate how local and global factors impact halo baryon mass content at redshifts of z≥ 5. Our model incorporates a time delay between when stars form and when they produce feedback, which drive bursts of star formation, and a mass and redshift dependent UV background, which captures the influence of cosmological reionization on gas accretion onto halos. We use statistically representative halo assembly histories and assume that the cosmological gas accretion rate is proportional to the halo mass accretion rate. Delayed feedback leads to oscillations in gas mass with cosmic time, behaviour that cannot be captured with instantaneous feedback. Highly efficient star formation drives stronger oscillations, while strong feedback impacts when oscillations occur; in contrast, inefficient star formation and weak feedback produce similar long-term behaviour to that observed in instantaneous feedback models. If the delayed feedback timescale is too long, a halo retains its gas reservoir but the feedback suppresses star formation. Our model predicts that lower mass systems (≤ 107 M_\odot) at z ≤ 10 should be strongly gas deficient, whereas higher mass systems retain their gas reservoirs because they are sufficiently massive to continue accreting gas through cosmological reionization. Interestingly, in higher mass halos, the median m_⋆/(m_⋆+mg) ≃ 0.01-0.05, but is a factor of 3-5 smaller when feedback is delayed. Our model does not include seed supermassive black hole feedback, which is necessary to explain massive quenched galaxies in the early Universe.