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Arxiv: A smooth filament origin for prolate galaxies "going bananas" in deep JWST images Published: 7/23/2024 12:40:32 PM Updated: 7/23/2024 12:40:32 PM

Paper abstract: We compare the abundant prolate shaped galaxies reported beyond z>3 in deepJWST surveys, with the predicted {\it stellar} appearance of young galaxies indetailed hydro-simulations of three main dark matter contenders: Cold (CDM),Wave/Fuzzy (\psiDM) and Warm Dark Matter (WDM). We find the observed galaxyimages closely resemble the elongated stellar appearance of young galaxiespredicted for both \psiDM and WDM, during the first ~eq 500Myr whilematerial steadily accretes from long, smooth filaments. The dark mater halos ofWDM and \psiDM also have pronounced, prolate elongation similar to the stars,indicating a shared, highly triaxial equilibrium. This is unlike CDM where theearly stellar morphology is mainly spheroidal formed from fragmented filamentswith frequent merging, resulting in modest triaxiality. Quantitatively, theexcess of prolate galaxies observed by JWST matches well WDM and \psiDM forparticle masses of 1.4KeV and 2.5\times 10^{-22} eV respectively. For CDM,several visible subhalos are typically predicted to orbit within the virialradius of each galaxy from subhalo accretion, whereas merging is initially rarefor WDM and \psiDM. We also verify with our simulations that \psiDM may bedistinguished from WDM by the form of the core, which is predicted to be smoothand centered for WDM, but is a dense soliton for \psiDM traced by stars andmeasurably offset from the galaxy center by random wave perturbations in thesimulations. We emphasise that long smooth filaments absent of galaxies mayprove detectable with JWST, traced by stars and gas with comoving lengths of150kpc predicted at z~eq10, depending on the particle mass of \psiDM orWDM.