The morphology of star-forming gas and its alignment with galaxies and dark matter haloes in the EAGLE simulations

ABSTRACT We present measurements of the morphology star-forming gas in galaxies from EAGLE simulations, and its alignment relative to stars dark matter (DM). Imaging such radio continuum enables weak lensing experiments that complement traditional optical approaches. Star-forming is typically more flattened than DM within halo centres, particularly for present-day structures total mass $\sim 10^{12-12.5}\, {\rm M}_\odot$, which preferentially host with rotationally supported stellar discs. Such systems have oblate, spheroidal distributions, but both less- more-massive subhaloes distributions tend be prolate, correlates positively significantly galaxy’s stars, terms sphericity triaxiality. The minor axis most commonly aligns subhalo’s central distribution, this often poor a prolate distribution. at centre parent subhalo less strongly case morphological closely kinematic axis, affording route observational identification unsheared axis. projected ellipticities are consistent shapes inferred high-fidelity images, they exhibit greater shape noise images owing characteristic flattening respect stars.