Bursty star formation during the Cosmic Dawn driven by delayed stellar feedback

Abstract

In recent years, several analytic models have demonstrated that simple assumptions about halo growth and feedback-regulated star formation can match the (limited) existing observational data on galaxies at z>6. By extending such models, we demonstrate that imposing a time delay on stellar feedback (as inevitably occurs in the case of supernova explosions) induces burstiness in small galaxies. Although supernova progenitors have short lifetimes (~5-30 Myr), the delay exceeds the dynamical time of galaxies at such high redshifts. As a result, star formation proceeds unimpeded by feedback for several cycles and "overshoots" the expectations of feedback-regulated star formation models. We show that such overshoot is expected even in atomic cooling halos, with masses up to ~10^10.5 Msun at z>6. However, these burst cycles damp out quickly in massive galaxies, because large haloes are more resistant to feedback so retain a continuous gas supply. Bursts in small galaxies - largely beyond the reach of existing observations - induce a scatter in the luminosity of these haloes (of ~1 mag) and increase the time-averaged star formation efficiency by up to an order of magnitude. This kind of burstiness can have substantial effects on the earliest phases of star formation and reionization.

15 pages, 10 figures, submitted to MNRAS

References in corpus (14)

• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• A Simple Technique for Predicting High-Redshift Galaxy Evolution
• Observational Evidence of Dynamic Star Formation Rate in Milky Way Giant Molecular Clouds
• Cloud Scale ISM Structure and Star Formation in M51
• The Global 21-cm Signal in the Context of the High-z Galaxy Luminosity Function
• Testing for calibration systematics in the EDGES low-band data using Bayesian model selection
• Stochastic modelling of star-formation histories II: star-formation variability from molecular clouds and gas inflow
• The Diversity and Variability of Star Formation Histories in Models of Galaxy Evolution
• The Effects of Population III X-ray and Radio Backgrounds on the Cosmological 21-cm Signal
• Formulating and critically examining the assumptions of global 21-cm signal analyses: How to avoid the false troughs that can appear in single spectrum fits
• Star Formation Stochasticity Measured from the Distribution of Burst Indicators
• AstraeusIV : Quantifying the star formation histories of galaxies in the Epoch of Reionization
• Quasi-equilibrium models of high-redshift disc galaxy evolution
• Effects of self-consistent rest-ultraviolet colours in semi-empirical galaxy formation models

Cited by in corpus (9)

• The brightest galaxies at Cosmic Dawn
• Balancing the efficiency and stochasticity of star formation with dust extinction in z > 10 galaxies observed by JWST
• What Causes The Formation of Disks and End of Bursty Star Formation?
• Rapid disc settling and the transition from bursty to steady star formation in Milky Way-mass galaxies
• Regulation of Star Formation by a Hot Circumgalactic Medium
• The Morphology of Reionization in a Dynamically Clumpy Universe
• LIMFAST. II. Line Intensity Mapping as a Probe of High-Redshift Galaxy Formation
• The role of Pop III stars and early black holes in the 21cm signal from Cosmic Dawn
• The extent of intergalactic metal enrichment from galactic winds during the Cosmic Dawn