The formation of early-type galaxies through monolithic collapse of gas clouds in Milgromian gravity

Studies of stellar populations in early-type galaxies (ETGs) show that the more massive form earlier and have a shorter star formation history (SFH). In this study, we investigate initial conditions ETG formation. The study begins with collapse non-rotating post-Big-Bang gas clouds Milgromian (MOND) gravitation. These produce ETGs star-forming timescales (SFT) comparable to those observed real Universe. Comparing these models observations, set constraints on size density order ETGs. effective-radius-mass relation model falls short relation. Possible mechanisms for later radius expansion are discussed. Using hydrodynamic MOND simulations work thus first time shows SFTs may be natural occurrence paradigm. We different feedback algorithms change evolution only very minor degree MOND. stars have, however, formed rapidly Universe than possible just from here studied gravitational mechanism. Dark-matter-based cosmological structure disagree at 5 sigma confidence.