James Webb Space Telescope Feed Post

Harvard ADS: Tracing star formation across cosmic time at tens of parsec-scales in the lensing cluster field Abell 2744

Paper abstract: We present a sample of 1956 individual stellar clumps at redshift 0.7 < z < 10, detected with JWST/NIRCam in 476 galaxies lensed by the galaxy cluster Abell2744. The lensed clumps present magnifications ranging between \mu=1.8 and \mu=300. We perform simultaneous size-photometry estimates in 20 JWST/NIRCam median and broad-band filters from 0.7 to 5 \mum. Spectral energy distribution (SED) fitting analyses enable us to recover the physical properties of the clumps. The majority of the clumps are spatially resolved and have effective radii in the range R_eff = 10 - 700 pc. We restrict this first study to the 1751 post-reionisation era clumps with redshift <5.5. We find a significant evolution of the average clump ages, SFR, SFR surface densities and metallicity with increasing redshift, while median stellar mass and stellar mass surface densities are similar in the probed redshift range. We observe a strong correlation between the clump properties and the properties of their host galaxies, with more massive galaxies hosting more massive and older clumps. We find that clumps closer to their host galactic center are on average more massive, while their ages do not show clear sign of migration. We find that clumps at cosmic noon sample the upper-mass end of the mass function to higher masses than at z>3, reflecting the rapid increase towards the peak of the cosmic star formation history. We conclude that the results achieved over the studied redshift range are in agreement with expectation of in-situ clump formation scenario from large-scale disk fragmentation.