BH2 - Theoretical and observational studies of astrophysical black holes |
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Speaker |
Musco, Ilia |
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Coauthors |
Cristiano Germani |
| Talk Title |
The power spectrum threshold for primordial black hole formation |
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Abstract |
Primordial black holes (PBHs) can form in the early Universe from the collapse of cosmological perturbations after cosmological horizon crossing. They are possible candidates for the dark matter component of the Universe as well as for the seeds of supermassive black holes that we observe today in the centres of galaxies. In calculations of spherically symmetric collapse, starting with a non linear curvature perturbation in the super horizon regime, the non linear evolution is simulated using a Lagrangian relativistic hydrodynamical code. If the perturbation is larger than a threshold depending on the equation of state and on the specific shape of the perturbation, a black hole is formed. In this talk I will discuss the dependence of PBH formation from the initial shape of the curvature profile showing the relation between the threshold amplitude and the steepness of the perturbation which is linked to the amplitude of the pressure gradients which arise during the collapse. I will then show how the initial shape can be determined from the power spectrum of cosmological perturbations, using a single field inflation model, calculating the correspondent abundance. The probability of forming PBHs within such scenario is exponentially easier than what previously thought. |
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