Accelerated Structure Formation: the Early Emergence of Massive Galaxies and Clusters of Galaxies
Stacy S. McGaugh, James M. Schombert, Federico Lelli, Jay Franck
arXiv:2406.17930v1 Announce Type: new
Abstract: Galaxies in the early universe appear to have grown too big too fast, assembling into massive, monolithic objects more rapidly than anticipated in the hierarchical $Lambda$CDM structure formation paradigm. The available data are consistent with there being a population of massive galaxies that form early ($z gtrsim 10$) and follow an approximately exponential star formation history with a short ($lesssim 1$ Gyr) e-folding timescale on the way to becoming massive ($M_* approx 10^{11};mathrm{M}_{odot}$) galaxies by $z = 0$, consistent with the traditional picture for the evolution of giant elliptical galaxies. Observations of the kinematics of spiral galaxies as a function of redshift similarly show that massive disks and their scaling relations were in place at early times, indicating a genuine effect in mass that cannot be explained as a quirk of luminosity evolution. That massive galaxies could form by $z = 10$ was explicitly predicted in advance by MOND. We discuss some further predictions of MOND, such as the early emergence of clusters of galaxies and the cosmic web.arXiv:2406.17930v1 Announce Type: new
Abstract: Galaxies in the early universe appear to have grown too big too fast, assembling into massive, monolithic objects more rapidly than anticipated in the hierarchical $Lambda$CDM structure formation paradigm. The available data are consistent with there being a population of massive galaxies that form early ($z gtrsim 10$) and follow an approximately exponential star formation history with a short ($lesssim 1$ Gyr) e-folding timescale on the way to becoming massive ($M_* approx 10^{11};mathrm{M}_{odot}$) galaxies by $z = 0$, consistent with the traditional picture for the evolution of giant elliptical galaxies. Observations of the kinematics of spiral galaxies as a function of redshift similarly show that massive disks and their scaling relations were in place at early times, indicating a genuine effect in mass that cannot be explained as a quirk of luminosity evolution. That massive galaxies could form by $z = 10$ was explicitly predicted in advance by MOND. We discuss some further predictions of MOND, such as the early emergence of clusters of galaxies and the cosmic web.