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Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/226876
- On the survival and abundance of disk-dominated galaxies
- Koda, Jun; Milosavljevic, Milos; Shapiro, Paul R.
- We study the formation of disk-dominated galaxies in a Λ cold dark matter (ΛCDM) universe. Their existence is considered to be a challenge for the ΛCDM cosmology, because galaxy mergers isotropize stellar disks and trigger angular momentum transport in gas disks, thus fostering the formation of central stellar spheroids. Here, we postulate that the formation of stellar spheroids from gas-rich disks is controlled by two parameters that characterize galaxy mergers, the mass ratio of merging dark matter halos, and the virial velocity of the larger merging halo. We utilize merger histories generated from realizations of the cosmological density field to calculate the fraction of dark matter halos that have avoided spheroid formation, and compare the derived statistics with the spheroid occupation fractions in surveys of nearby galaxies. We find, for example, that the survival rate of disk-dominated galaxies in ΛCDM is just high enough to explain the observed fractional representation of disk-dominated galaxies in the universe if the only mergers which lead to central spheroid formation are those with mass ratios M 2 / M 1 > 0.3 and virial velocities V vir,1 > 55kms –1 . We discuss the physical origin of this criterion.
- Publication type
- Journal article
- The Astrophysical Journal, Vol. 696, no. 1 (May 2009), pp. 254-260
- Publication year
- FOR Code(s)
- 0201 Astronomical and Space Sciences; 0305 Organic Chemistry; 0306 Physical Chemistry (Incl. Structural)
- Cold dark matter; Dark matter; Disk-dominated galaxies
- Institute of Phyics Publishing
- Publisher URL
- Copyright © 2009. The American Astronomical Society. All rights reserved. The American Astronomical Society does not allow institutions to archive either the accepted manuscript or the published version of the article. However, you can find an earlier version of the full text here: http://arxiv.org/abs/0711.3014
- Peer reviewed