2011/06/30 by Emilio Romano-Diaz, Emilio Romano-Díaz, Jun-Hwan Choi +2 · 2 citations
Engineering · Physics and Astronomy · #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Halo #QSOS #RADIUS #Redshift #Reionization #Space Technology and Applications #Stellar mass #astro-ph.CO
paper · pdf · doi:10.1088/2041-8205/738/2/l19
To be published by the Astrophysical Journal Letters, 5 pages, 3 figures. Small corrections following the referee report
arxiv created 2011/08/03 · openalex publication_date 2011/08/17 · arxiv updated 2015/05/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Using a high-resolution cosmological numerical simulation, we have analyzed the evolution of galaxies at z ∼ 10 in a highly overdense region of the universe. These objects could represent the high-redshift galaxies recently observed by the Hubble's Wide Field Camera 3 and could as well be possible precursors of QSOs at z ∼ 6–7. To overcome the sampling and resolution problems in cosmological simulations of these rare regions, we have used the constrained realizations method. Our main result for z ∼ 10 shows the high-resolution central region of 3.5 h −1 Mpc radius in comoving coordinates being completely dominated by disk galaxies in the total mass range of ≳ 10 9 h −1 M ☉ . We have verified that the gaseous and stellar disks we identify are robust morphological features, capable of surviving the ongoing merger process at these redshifts. Below this mass range, we find a sharp decline in the disk fraction to negligible numbers. At this redshift, the disks appear to be gas-rich compared to z = 0, and the dark matter halos baryon-rich, by a factor of ∼2–3 above the average fraction of baryons in the universe. The dominance of disk galaxies in the high-density peaks during the epoch of re-ionization is contrary to the morphology–density trend observed at low redshifts.