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mentors
Prof. Matthew Bailes
Dr. Chris Flynn
Saurav Mishra
Contributors
Rudra Sekhri
Evie Spilias
Hendrik Combrinck
Rebecca Koehne
Ruoyao Ni
Credits
Report written by Rudra Sekhri and Hendrik Combrinck
All members of this project contributed equally to the research phase of the project.
Specific credit to Robert, Hendrik and Rudra for working on checking detection significances using filtered samples of the final dataset, Evie and Rebecca for their work on chi2 distributions, Rudra for working on the data cleaning pipeline for both 16-band and 32-band arrival timing datasets, as well as the DM fitting and FD corrections processes to produce the final datasets. Also credits to Hendrik and Robert for developing new plotting tools in Python to quickly inspect and "interrogate" the data. Credit also goes to Saurav Mishra for his contributions in fixing the mean ToA offsets for each pulsar through the use of DM modelling through Gaussian processes, etc.
Thanks to Dr. Matt Miles, Dr. Daniel Reardon, Dr. Ryan Shannon for their immense contributions by providing the noise models and the code to search for Hellings-Downs correlations, as well as an in-depth understanding of how these noise models worked. Also thanks to Jacob Askew (Swinburne) for assisting in helping us understand the applications of high-frequency resolution pulsar timing data, especially, in the understanding properties of the interstellar medium through scintillation patterns in archive data.
Finally, thank you to Dr. Chris Flynn and Prof. Matthew Bailes for supervising this project. This project is funded by A.S.T.R.A.L..
Introduction
Pulsar timing arrays (PTAs) offer a new method to detect nano-hertz gravita tional waves through a spatial correlation between the times of arrivals (ToAs) between pairs of pulsars. We report a detection of nHz gravitational waves with an estimated detection significance of approx 7σ using the Karoo Array Telescope (MeerKAT) PTA project. An earlier analysis retrieved a significance of ∼ 5.85σ. Our re-analysis used a sample of 8387 observations from 83 millisecond pulsars (MSPs) over the course of 4 years, with a signal amplitude of A = 5 × 10-15.
