Asada+2023 : an apparent major merger of two 𝑧 ∼ 5 ultra-low-mass galaxies (𝑀 ∼ 107𝑀) that are doubly imaged and magnified by cluster. both galaxies are experiencing synchronized starburst.  They have subsolar metallicity (0.2Zsun) and are connected by an even more metal poor bridge.  these ultra low mass galaxies are believed to be responsible for reionising the universe. Merger triggered starbursts could be significant contributors to the ionising photon budget of the universe.


Jin+2023: Discovery of a compact group of galaxies in EGS field covered by CEERS. Group members and z from NIRCAM + HST+ IRAC photometry. The most massive galaxy in the group has a stellar mass log(M∗/M⊙) ≈ 9.8, while the rest are low-mass satellites (log(M∗/M⊙) ≈ 8.4–9.2).Sensitivity and resolution of JWST important for identification of low masses and compactness of the structure. Comparison  with similar structures in EAGLE: they will all merger into a single galaxy by z~3 and form 10^11 galaxies at z~1. Proto-massive galaxy!


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