paper

Mini-quenching of galaxies by bursty star formation

arXiv:2305.07066 · doi:10.1093/mnras/stad3239

Abstract

The recent reported discovery of a low-mass and an intermediate-mass quenched galaxy with JWST/NIRSpec is the first evidence of halted star formation above . Here we show how bursty star formation at gives rise to temporarily quenched, or mini-quenched galaxies in the mass range using four models of galaxy formation: the periodic box simulation IllustrisTNG, the zoom-in simulations VELA and FirstLight and an empirical halo model. The main causes for mini-quenching are stellar feedback, lack of gas accretion onto galaxies and galaxy-galaxy interactions. The abundance of (mini-)quenched galaxies agrees across the models: the population first appears below , after which their proportion increases with cosmic time, from % at to % at , corresponding to comoving number densities of Mpc and Mpc, respectively. These numbers are consistent with star formation rate duty cycles inferred for VELA and FirstLight galaxies. Their star formation histories (SFHs) suggest that mini-quenching at is short-lived with a duration of Myr, which is close to the free-fall timescale of the inner halo. However, mock spectral energy distributions of mini-quenched galaxies in IllustrisTNG and VELA do not match JADES-GS-z7-01-QU photometry, unless their SFHs are artificially altered to be more bursty on timescales of Myr. Studying mini-quenched galaxies might aid in calibrating sub-grid models governing galaxy formation, as these may not generate sufficient burstiness at high redshift to explain the SFH inferred for JADES-GS-z7-01-QU.

13 pages, 5 figures, 5 tables

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