Alladi Ramakrishnan Hall

Decoding cosmic fingerprints: constraining the generation and evolution of primordial fluctuations

Dhiraj Hazra

Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Bologna

It is the origin and evolution of quantum fluctuations that eventually lead
to the formation of the Large Scale Structure (LSS) in the Universe. The
primordial perturbations emerge through the radiation and thereafter the
matter dominated epochs and finally to today's dark energy dominated epoch,
leaving their distinct fingerprints in the photons that we observe. Photons
from the Cosmic Microwave Background (CMB), quasars, galaxies and clusters,
supernovae, stars etc. can be analyzed to trace these fingerprints. In this
talk, I will mainly discuss decoding three different fingerprints
originating from three different epochs in the timeline of the Universe,
namely, CMB from the last scattering surface, Lyman-alpha observations from
reionization and post-reionization eras and the galaxies observed in the
LSS. Since information from different cosmological processes are convolved
in our observations, effective joint analyses are required to converge
towards the most probable model of the Universe. I will outline the
standard model and few extensions beyond that agree remarkably with the
present data. I will also discuss model independent reconstruction methods
that can lead to possible scenarios of the Universe directly from the data.
I will conclude with forecasts from the upcoming and proposed cosmological
missions.