Cutoff in the Lyman-alpha forest power spectrum: warm IGM or warm dark matter?

Date: 10 November 2015 15PM (CET)

Title: Cutoff in the Lyman-alpha forest power spectrum: warm IGM or warm dark matter?

Presenter: Antonella Garzilli, Lorentz Institute, Leiden University

Abstract: We review how the Lyman-alpha forest, one of the observables of the intergalactic medium, can be used to constraint the warmness of dark matter. We re-analyse high redshift and high resolution Lyman-alpha forest spectra from (Viel et al 2013) seeking to constrain properties of warm dark matter particles.  Compared to the previous work we consider a wider range on thermal histories of the intergalactic medium and find that both warm and cold dark matter models can explain the cut-off observed in the flux power spectra of high-resolution observations equally well.  This implies, however, very different thermal histories and underlying re-ionisation models. We discuss the implication of our new constraints of warm dark matter on realistic sterile neutrino models. We illustrate a new method to constrain the intergalactic medium thermal history, and we discuss how to remove the degeneracy between temperature and the warmness of dark matter.