Constraining quenching time-scales in galaxy clusters by forward-modelling stellar ages and quiescent fractions in projected phase space

Journal Article · 12 April 2023 · Monthly Notices of the Royal Astronomical Society

DOI: https://doi.org/10.1093/mnras/stad1069 · OSTI ID:1971288

Reeves, Andrew M. M.  ^[1]; Hudson, Michael J.  ^[2]; Oman, Kyle A.  ^[3]

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1. Univ. of Waterloo, ON (Canada)
2. Univ. of Waterloo, ON (Canada); Perimeter Inst. for Theoretical Physics, Waterloo, ON (Canada)
3. Durham Univ. (United Kingdom)

We forward-model mass-weighted stellar ages (MWAs) and quiescent fractions (f_Q) in projected phase space (PPS), using data from the Sloan Digital Sky Survey, to jointly constrain an infall quenching model for galaxies in log (M_vir/M_⊙) > 14 galaxy clusters at z ∼ 0. We find the average deviation in MWA from the MWA–M⋆ relation depends on position in PPS, with a maximum difference between the inner cluster and infalling interloper galaxies of ∼1 Gyr. Our model employs infall information from N-body simulations and stochastic star-formation histories from the universemachine model. We find total quenching times of t_Q = 3.7 ± 0.4 Gyr and t_Q = 4.0 ± 0.2 Gyr after first pericentre, for 9 < log (M_⋆/M_⊙) < 10 and 10 < log (M_⋆/M_⊙) < 10.5 galaxies, respectively. By using MWAs, we break the degeneracy in time of quenching onset and time-scale of star formation rate (SFR) decline. We find that time of quenching onset relative to pericentre is $$t_{\mathrm{delay}}=3.5^{+0.6}_{-0.9}$$ Gyr and $$t_{\mathrm{delay}}=-0.3^{+0.8}_{-1.0}$$ Gyr for 9 < log (M_⋆/M_⊙) < 10 and 10 < log (M_⋆/M_⊙) < 10.5 galaxies, respectively, and exponential SFR suppression time-scales are τenv ≤ 1.0 Gyr for 9 < log (M_⋆/M_⊙) < 10 galaxies and τenv ∼ 2.3 Gyr for 10 < log (M_⋆/M_⊙) < 10.5 galaxies. Stochastic star formation histories remove the need for rapid infall quenching to maintain the bimodality in the SFR of cluster galaxies; the depth of the green valley prefers quenching onsets close to first pericentre and a longer quenching envelope, in slight tension with the MWA-driven results. Taken together these results suggest that quenching begins close to, or just after pericentre, but the time-scale for quenching to be fully complete is much longer and therefore ram-pressure stripping is not complete on first pericentric passage.

• Research Organization: US Department of Energy (USDOE), Washington, DC (United States). Office of Science, Sloan Digital Sky Survey (SDSS)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC)
• OSTI ID: 1971288
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 2 Vol. 522; ISSN 0035-8711
• Publisher: Oxford University PressCopyright Statement
• Country of Publication: United States
• Language: English