Near-IR clumps and their properties in high-<i>z</i> galaxies with <i>JWST</i>/NIRCam

ABSTRACT Resolved stellar morphology of $z\gt 1$ galaxies was inaccessible before JWST. This limitation, due to the impact of dust on rest-frame UV light, had withheld major observational conclusions required to understand the importance of clumps in galaxy evolution. Essentially independent of this issue, we use the rest-frame near-IR for a stellar-mass dependent clump detection method and determine reliable estimations of selection effects. We exploit publicly available JWST/NIRCam and HST/ACS imaging data from CEERS, to create a stellar-mass based picture of clumps in a mass-complete sample of 418 galaxies within a wide wavelength coverage of $0.5{\!-\!}4.6\, \mu$m and a redshift window of $1 \lt z \lt 2$. We find that a near-IR detection gives access to a larger, and possibly different, set of clumps within galaxies, with those also detected in UV making up only 28 per cent. Whereas, 85 per cent of the UV clumps are found to have a near-IR counterpart. These near-IR clumps closely follow the UVJ classification of their respective host galaxies, with these hosts mainly populating the star-forming regime besides a fraction of them (16 per cent) that can be considered quiescent. The mass of the detected clumps are found to be within the range of $10^{7.5{\!-\!}9.5}\, \rm {\rm M}_{\odot }$, therefore expected to drive gas into galaxy cores through tidal torques. The clump stellar mass function is found to have a slope of $-1.50 \pm 0.14$, indicating a hierarchical nature similar to that of star-forming regions in the local Universe. Finally, we observe a radial gradient of increasing clump mass towards the centre of galaxies.