TY - JOUR
T1 - 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
AU - Ji, Zhiyuan
AU - Williams, Christina C.
AU - Tacchella, Sandro
AU - Suess, Katherine A.
AU - Baker, William M.
AU - Alberts, Stacey
AU - Bunker, Andrew J.
AU - Johnson, Benjamin D.
AU - Robertson, Brant
AU - Sun, Fengwu
AU - Eisenstein, Daniel J.
AU - Rieke, Marcia
AU - Maseda, Michael V.
AU - Hainline, Kevin
AU - Hausen, Ryan
AU - Rieke, George
AU - Willmer, Christopher N. A.
AU - Egami, Eiichi
AU - Shivaei, Irene
AU - Carniani, Stefano
AU - Charlot, Stephane
AU - Chevallard, Jacopo
AU - Curtis-Lake, Emma
AU - Looser, Tobias J.
AU - Maiolino, Roberto
AU - Willott, Chris
AU - Chen, Zuyi
AU - Helton, Jakob M.
AU - Lyu, Jianwei
AU - Nelson, Erica
AU - Bhatawdekar, Rachana
AU - Boyett, Kristan
AU - Sandles, Lester
N1 - © 2024 The Author(s). This is an open access article distributed under the Creative Commons Attribution License, to view a copy of the license, see: https://creativecommons.org/licenses/by/4.0/
PY - 2024/10/9
Y1 - 2024/10/9
N2 - We present a spatially resolved study of stellar populations in six galaxies with stellar masses M * ∼ 1010 M ☉ at z ∼ 3.7 using 14-filter James Webb Space Telescope (JWST)/NIRCam imaging from the JADES and JEMS surveys. The six galaxies are visually selected to have clumpy substructures with distinct colors over rest frame 3600−4100 Å, including a red, dominant stellar core that is close to their stellar-light centroids. With 23-filter photometry from the Hubble Space Telescope to JWST, we measure the stellar-population properties of individual structural components via spectral energy distribution fitting using Prospector. We find that the central stellar cores are ≳2 times more massive than the Toomre mass, indicating they may not form via single in situ fragmentation. The stellar cores have stellar ages of 0.4−0.7 Gyr that are similar to the timescale of clump inward migration due to dynamical friction, suggesting that they likely instead formed through the coalescence of giant stellar clumps. While they have not yet quenched, the six galaxies are below the star-forming main sequence by 0.2−0.7 dex. Within each galaxy, we find that the specific star formation rate is lower in the central stellar core, and the stellar-mass surface density of the core is already similar to quenched galaxies of the same masses and redshifts. Meanwhile, the stellar ages of the cores are either comparable to or younger than the extended, smooth parts of the galaxies. Our findings are consistent with model predictions of the gas-rich compaction scenario for the buildup of galaxies’ central regions at high redshifts. We are likely witnessing the coeval formation of dense central cores, along with the onset of galaxy-wide quenching at z > 3.
AB - We present a spatially resolved study of stellar populations in six galaxies with stellar masses M * ∼ 1010 M ☉ at z ∼ 3.7 using 14-filter James Webb Space Telescope (JWST)/NIRCam imaging from the JADES and JEMS surveys. The six galaxies are visually selected to have clumpy substructures with distinct colors over rest frame 3600−4100 Å, including a red, dominant stellar core that is close to their stellar-light centroids. With 23-filter photometry from the Hubble Space Telescope to JWST, we measure the stellar-population properties of individual structural components via spectral energy distribution fitting using Prospector. We find that the central stellar cores are ≳2 times more massive than the Toomre mass, indicating they may not form via single in situ fragmentation. The stellar cores have stellar ages of 0.4−0.7 Gyr that are similar to the timescale of clump inward migration due to dynamical friction, suggesting that they likely instead formed through the coalescence of giant stellar clumps. While they have not yet quenched, the six galaxies are below the star-forming main sequence by 0.2−0.7 dex. Within each galaxy, we find that the specific star formation rate is lower in the central stellar core, and the stellar-mass surface density of the core is already similar to quenched galaxies of the same masses and redshifts. Meanwhile, the stellar ages of the cores are either comparable to or younger than the extended, smooth parts of the galaxies. Our findings are consistent with model predictions of the gas-rich compaction scenario for the buildup of galaxies’ central regions at high redshifts. We are likely witnessing the coeval formation of dense central cores, along with the onset of galaxy-wide quenching at z > 3.
KW - Galaxy quenching
KW - High-redshift galaxies
KW - Galaxy formation
KW - Galaxy evolution
KW - Galaxy structure
U2 - 10.3847/1538-4357/ad6e7f
DO - 10.3847/1538-4357/ad6e7f
M3 - Article
SN - 0004-637X
VL - 974
SP - 1
EP - 27
JO - The Astrophysical Journal
JF - The Astrophysical Journal
IS - 1
M1 - 135
ER -