Home List of Titles The velocity function in the local environment from lambda CDM and lambda WDM constrained simulations
Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/229531
- The velocity function in the local environment from lambda CDM and lambda WDM constrained simulations
- Zavala, J.; Jing, Y. P.; Faltenbacher, A.; Yepes, G.; Hoffman, Y.; Gottloeber, S.; Catinella, B.
- Using constrained simulations of the local universe for generic cold dark matter (CDM) and for 1 keV warm dark matter (WDM), we investigate the difference in the abundance of dark matter halos in the local environment. We find that the mass function (MF) within 20 h -1 Mpc of the Local Group is 2 times larger than the universal MF in the 10 9-10 13 h -1 M mass range. Imposing the field of view of the ongoing H I blind survey Arecibo Legacy Fast ALFA (ALFALFA) in our simulations, we predict that the velocity function (VF) in the Virgo-direction region (VdR) exceeds the universal VF by a factor of 3. Furthermore, employing a scheme to translate the halo VF into a galaxy VF, we compare the simulation results with a sample of galaxies from the early catalog release of ALFALFA. We find that our simulations are able to reproduce the VF in the 80-300 km s -1 velocity range, having a value 10 times larger than the universal VF in the VdR. In the low-velocity regime, 35-80 km s -1, the WDM simulation reproduces the observed flattening of the VF. In contrast, the simulation with CDM predicts a steep rise in the VF toward lower velocities; for V max = 35 km s -1, it forecasts 10 times more sources than the ones observed. If confirmed by the complete ALFALFA survey, our results indicate a potential problem for the CDM paradigm or for the conventional assumptions about energetic feedback in dwarf galaxies.
- Publication type
- Journal article
- Astrophysical Journal Letters, Vol. 700, no. 2 (Aug 2009), pp. 1779-1793
- Publication year
- FOR Code(s)
- 0201 Astronomical and Space Sciences
- Cold dark matter; Dark matter; Haloes; Warm dark matter
- Institute of Physics Publishing
- Publisher URL
- Copyright © 2009 The American Astronomical Society. The American Astronomical Society does not allow Swinburne Research Bank 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/0906.0585
- Peer reviewed