COSMOS-Web: star formation along the early Hubble sequence and the evolution of dust over the redshift range 0‌‌‌‌ <‌ z < 12

Artikel i vetenskaplig tidskrift, 2026

We have carried out a stacking analysis with the COSMOS-Web catalogue on one of the deepest ever SCUBA-2 images at 850-(Formula presented) m, allowing us to estimate the mean submillimetre flux density for samples of galaxies split by stellar mass and morphological class over the redshift range (Formula presented). For all morphological classes, the mean star formation rate estimated from the dust emission increases with redshift, reaching a value for the most massive galaxies ((Formula presented) ) of (Formula presented) at (Formula presented). In this redshift range, the mean star formation rate ‌for these galaxies falls along the Hubble sequence from (Formula presented) for irregular galaxies at one end to (Formula presented)  for spheroids at the other end, which shows that quenching was already happening shortly after the emergence of the Hubble sequence. We also show that the transformation of ‘submillimetre galaxies’ can reproduce the growth in number density of massive bulge-dominated and spheroidal galaxies over the redshift range (Formula presented). As a side project, we have used our stacking results to determine the relationship between the mean density of dust and redshift in the range (Formula presented). We show that a chemical evolution model based on the ‘star formation history’ of the universe, with a gas outflow rate equal to the star formation rate, can explain the monotonic rise with redshift in the dust-to-stellar mass ratio and reproduce the relationship between mean dust density and redshift remarkably accurately.