Work

Growth from KiDS: Stellar mass assembly of galaxies since z=2 in the light of Kilo-Degree Survey

Year: 2026

Type: article

Abstract: We measure the galaxy stellar mass function (GSMF) at z = 0–2 using 28 million galaxies from the KiDS DR4, which spans an effective survey area of 676.9 deg 2 . Combining nine-band photometry ( u – K s ) and redshifts derived using deep learning photometry, we use five SED fitting configurations: CIGALE (combined with delayed exponential declining star formation history)/LePhare (combined with exponential declining star formation history) and CB19/BC03/M05 stellar population synthesis (SPS). We present the impact of the systematics related to the code, SPS modeling and star formation history (SFH), which combined can introduce systematics of ∼0.6 dex. The GSMFs outlined in this work agree well with previous studies (within the uncertainties introduced by systematics) that typically are able to cover measurements for the GSMF only up to log( M * / M ⊙ ) ∼ 11.75, due to their limited volume. The large KiDS area and galaxy counts, allow us to gain some insights on the “extreme” high-mass end, and our GSMFs imply that possibly there are more massive galaxies than we would expect, from a simple exponential cut-off, at log( M * / M ⊙ ) > 11.75. However, we heed caution that, despite advances done both in redshift estimation techniques and SPS, future studies are required to confirm this behavior. We consider the effects of Eddington bias (EB) to our observations via two different methods and compare our results with the predictions of semi-analytic models and hydrodynamical simulations. We use the mean absolute difference (MAD) of residuals as a diagnostic metric. Due to inconsistencies (> 0.5 dex) between observations and Eddington-biased simulations found, especially at the high-mass end, we suggest that some theoretical models would achieve better performance once parameter tuning takes into account the effects of EB prior to the tuning of the uncertain parameters involved related to stellar physics and feedback.

Source: Science China Physics Mechanics and Astronomy

DOI: 10.1007/s11433-026-3075-9