Speaker
Dr
Rajat Mani Thomas
(Institute of Physics and Mathematics of the Universe)
Description
The redshifted 21-cm cosmological signal emanating from the "dark ages of the
universe" as it transitions into the Epoch of Reionization (EoR) began to be
intensely investigated in the last decade. The studies became all the more urgent as
a result of unprecedented possibilities in signal extraction offered by large
upcoming radio telescope arrays like LOFAR, MWA and SKA. From a theoretical
perspective, challenges in predicting the 21(1+z) signal stem from the inadequacies
of our understanding of the astrophysical processes that dominated the Universe
before redshift 6. Apart from the nature of the first sources (Pop III stars,
mini-quasars, dark matter annihilation) that ionized the Universe, there is a
plethora of unknown entities that affect the signal as it traverses the Universe,
impinges on the ionosphere, and ultimately enters the observation window of the
telescope. The focus of the research reported in this thesis was the development of a
fast and efficient radiative transfer (RT) scheme able to accurately predict the
21-cm cosmological signal, modulo the detection capability of the LOFAR telescope.
The fast and novel scheme we propose here facilitates the spanning of large parameter
spaces dictated by the astrophysical unknowns. The simulations that form part of the
scheme provide the starting point for the LOFAR-EoR simulation pipeline. These mock
datacubes will subsequently be used in conjunction with datasets of other
measurements like the CMB and deep near-IR to test our calibration and signal
extraction schemes and to extract more information about the "dark ages".
Primary author
Dr
Rajat Mani Thomas
(Institute of Physics and Mathematics of the Universe)
