Early structure formation from primordial density fluctuations with a blue-tilted power spectrum

Understand

While observations of large-scale structure and the cosmic microwave background (CMB) provide strong constraints on the amplitude of the primordial power spectrum (PPS) on scales larger than 10~Mpc, the amplitude of the power spectrum on sub-galactic length scales is much more poorly constrained.

• We study early structure formation in a cosmological model with a blue-tilted PPS.
• We assume that the standard scale-invariant PPS is modified at small length scales as $P(k) \sim k^{m_{\rm s}}$ with $m_{\rm s} > 1$.
• We run a series of cosmological hydrodynamic simulations to examine the dependence of the formation epoch and the characteristic mass of primordial stars on the tilt of the PPS.