25th of August 2021 |
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ATNF Colloquium |

Investigating Traditional Radio Astronomy Techniques in an EoR Context |

Nichole Barry (ICRAR-Curtin) |

Abstract:
Detecting the Epoch of Reionisation is a major directive of the future
SKA, and an active area of research for SKA-precursors including the
MWA. However, measuring the 21cm signal of primordial hydrogen
requires a delicate intersection of precision, sensitivity, and
advanced mathematical techniques. We investigate previous standards of
radio astronomy software in order to understand their inherent level
of error and to determine requirements for the MWA and subsequently
the SKA.
In particular, interferometers measure millions and millions of visibilities every minute, which live neither in image space nor fully Fourier space. Thus, many of our analysis techniques revolve around the use of FFTs and histogramming procedures. However, given the faint, spectral nature of the signal we are trying to detect, we show ways that these traditional techniques fail to reach the required precision. The graphic above compares the differences between an analytic Fourier transform (top right panel) and FFTs (bottom right panels) of the beam image sensitivity (left panel), which is used in most all traditional radio astronomy analyses. These differences are important for sensitive measurements like the 21 cm signal from the early Universe and widefield instrumentation like the MWA and SKA. |