2026/02/18 by Massimo Stiavelli, Massimo Ricotti · 1 voice
#astro-ph.GA
Motivated by observational evidence from JWST and theoretical results from cosmological simulations, we use a simple parametric, phenomenological model to test to what extent bursty star formation with standard Initial Mass Function, no continuous star formation, no mergers, \mrand no dust can account for the observed properties in the MUV vs M_* plane of galaxies at redshifts z>5. We find that the simplest model that fits the data has a quiescence period between bursts Δt ∼ 100~Myrs and the stellar mass in each galaxy grows linearly as a function of time from z=12 to z=5 (i.e., repeated bursts in each galaxy produce approximately equal mass in stars). The distribution of burst masses across different galaxies follows a power-law dN/dM_* ∝ M_*α with slope α∼ -2. At z>9-10 the observed galaxy population typically had only one or two bursts of stars formation, hence the observed stellar masses at these redshifts (reaching M_* ∼ 1010~M_\odot), roughly represent the distribution of masses formed in one burst.