GALAXY FORMATION IN HEAVILY OVERDENSE REGIONS AT z {approx} 10: THE PREVALENCE OF DISKS IN MASSIVE HALOS
- Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506-0055 (United States)
- Department of Astrophysical and Planetary Sciences, CASA University of Colorado, Boulder, CO 80309 (United States)
Using a high-resolution cosmological numerical simulation, we have analyzed the evolution of galaxies at z {approx} 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 {approx} 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 {approx} 10 shows the high-resolution central region of 3.5 h {sup -1} Mpc radius in comoving coordinates being completely dominated by disk galaxies in the total mass range of {approx}> 10{sup 9} h {sup -1} M{sub sun}. 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 {approx}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.
- OSTI ID:
- 21562439
- Journal Information:
- Astrophysical Journal Letters, Vol. 738, Issue 2; Other Information: DOI: 10.1088/2041-8205/738/2/L19; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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