Oral Presentation

The role of clumps in galaxy evolution unveiled by JWST and ALMA

Author(s):

Presenter: Boris Sindhu Kalita (Kavli-IPMU)

In the study of galaxy evolution, we are yet to understand the significance of the 'clumpiness' observed in high-redshift (z>1) galaxies, primarily investigated in rest-frame UV. I will be presenting our work on galaxy clumps, that exploits JWST/NIRCam, HST/ACS, and high-resolution ALMA continuum imaging. By utilising the CEERS and FMOS JWST+HST databases to access rest-frame UV, optical, and near-IR data from galaxies within the z = 1-2 range, we achieve precise and resolved estimations of their stellar mass distributions. We find that the previously identified UV clumps in galaxies from this epoch constitute components of underlying, more abundant 'stellar clumps', detectable up to rest-frame near-IR wavelengths. We find these structures to have sufficient mass to drive gas to galaxy cores via gravitational torques, also supported by radial property gradients. Additionally, star formation in the galaxy bulge exhibits correlations with the total mass of clumps, further substantiating this scenario. High-resolution ALMA sub-mm continuum observations in the FMOS sample enable these measurements, allowing the spatial separation of core and disk star formation. Moreover, the net stellar mass of bulges show strong correlations with clump masses. This further links bulge formation and stellar clumps. Lastly, I will also show evidence of the bulge stabilising the gas in the disk, inhibiting further clump formation and driving morphological quenching across the galaxy.