ACP Seminar (Astronomy - Cosmology - Particle Physics)

Speaker: Rajat Mani Thomas (IPMU)
Title: Fast Reionization Simulations for LOFAR
Date (JST): Thu, Sep 24, 2009, 13:30 - 14:30
Place: Seminar Room at IPMU Prefab. B
Related File: 149.pdf
Abstract: The redshifted 21-cm cosmological signal from the "dark ages of the
universe" as it transitions into the epoch of reionization (EoR) has been a
subject of intense study in the last decade, fueled by the promise of
upcoming large radio telescope arrays like LOFAR, MWA and SKA. From a
theoretical perspective, challenges in predicting the 21(1+z) signal stems
from our lack of understanding the astrophysical processes that dominate the
Universe before redshift six. Apart from the nature of the first sources
(PopIII stars, mini-quasars, dark matter annihilation) that ionized the
Universe, there are a plethora of other uncertainties that affect the signal
as it traverses the Universe to impinge on the ionosphere and down to the
telescope. The focus of this thesis was the development of a fast and
efficient radiative transfer (RT) scheme that provides an accurate
prediction of the cosmological 21-cm signal, modulo the detection capability
of the LOFAR telescope. Our novel and fast approach facilitates spanning
large parameter spaces dictated by the astrophysical unknowns. These
simulations provide the starting point for the LOFAR-EoR simulation
pipeline. Subsequently these mock datacube will be used to test the
calibration and signal extraction schemes being developed and also in
conjunction with datasets of other measurements like the CMB and deep
near-IR, to extract even more information about the "dark ages".