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Warm Dark Matter

The ΛCDM model describes structure formation at large scales very well; however, it fails on small scales: this standard model predicts much more small-scale structure than observed.  We compared the observed spectrum of minivoids in the local volume with the spectrum of minivoids determined from the simulations and showed that contrary to the ΛCDM, the ΛWDM model can naturally explain both the observed spectrum of minivoids and the presence of low-mass galaxies observed in the local volume.

“The sizes of mini-voids in the local universe: an argument  in favor of a warm dark matter model?” ([ADS][MNRAS]),
A.V. Tikhonov, S. Gottlöber, G. Yepes, Y. Hoffman, MNRAS 399 (2009)  1611.

We also studied the difference of the abundance of dark matter halos in the environment of the Local Group assuming Cold or Warm Dark Matter in the constrained simulations. We compared the theoretical predictions with observational data from the ongoing HI blind survey Arecibo Legacy Fast ALFA (ALFALFA) and found that the Warm Dark Matter simulation reproduces the observed flattening of the velocity function very well whereas the Cold Dark Matter simulation predicts a steep rise toward lower velocities.

“The velocity function in the local environment from ΛCDM and ΛWDM constrained simulations” ([ADS][ApJ]),
J. Zavala, Y. P. Jing, A. Faltenbacher, G. Yepes, Y. Hoffman, S. Gottlöber and B. Catinella, ApJ 700 (2009), 1779.