JADES + JEMS: A Detailed Look at the Buildup of Central Stellar Cores and Suppression of Star Formation in Galaxies at Redshifts 3 < z < 4.5

Understand

We present a spatially resolved study of stellar populations in 6 galaxies with stellar masses $M_*\sim10^{10}M_\odot$ at $z\sim3.7$ using 14-filter JWST/NIRCam imaging from the JADES and JEMS surveys.

• The 6 galaxies are visually selected to have clumpy substructures with distinct colors over rest-frame $3600-4100\r{A}$, including a red, dominant stellar core that is close to their stellar-light centroids.
• With 23-filter photometry from HST to JWST, we measure the stellar-population properties of individual structural components via SED fitting using Prospector.
• We find that the central stellar cores are $\gtrsim2$ times more massive than the Toomre mass, indicating they may not form via single in-situ fragmentation.