• cosmologia
• mezzo intergalattico
• simulazioni

The scintillation phenomenon consists in a light wave, coming from a compact enough source, that, passing through a ionized inhomogeneous medium, is subject to a random variation of the refraction index, and thus suffers multiple phase changes which lead to fluctuations in all the wave related quantities; the aim of this Thesis is to exploit the effects of this process when the light comes from a distant quasar and the random medium is given by the InterGalactic Medium, namely the baryon mass fraction of the universe laying between galaxies that is not locked up in stellar objects.

The motivation that drives us toward this purpose is that either until now in this specific context a full investigation has not been developed
in the literature, and either the IGM scintillation can, as we eventually show, be relevant in explaining some of the current discrepancies between theory and observations; furthermore this can prove to be a useful investigation tool, complementary to the ones available.

To achieve the result proposed we have decided to employ the standard cosmological model, which gives the proper tools to analyze the environment we want to deal with, which is described in Chapter 1, and to numerically simulate the IGM, with the tools provided and depicted in Chapter 2.
Next, in Chapter 3, we review the scintillation physical basis and its application to the InterStellar Medium, and then we naturally extend the ISM results to the IGM case. In Chapter 4 we expose and discuss the results of the simulation and finally, in Chapter 5, we apply our
model to the simulation and analyze the behaviour of the IGM scintillation, confronting it with the observations. To conclude, in Chapter 6 we summarize the results obtained and the possible future developments.