RESEARCHERS from the Australian International Gravitational Research Centre (AIGRC) based at UWA, are investigating a new technique which could potentially place Australia at the forefront of international fundamental physics and bring benefits to the Australian science and technology industries.
Associate Professor Linqing Wen, who is leading the research, is collaborating with physicist Yanbei Chen from the California Institute of Technology to examine the new method which mimics the operation of the human ear to detect ‘chirp’ signals buried within gravitational waves.
According to the Director of the AIGRC, Winthrop Professor David Blair, gravitational waves are ripples in space generated by cosmic events such as colliding stars, black holes, and supernova explosions. Professor Blair says that when these objects omit each other, they produce what is known as a characteristic ‘chirp’ signal.
He says one of the major aims of inventing this new technique is to enable the gravitational wave community to detect signals instantly in real-time.
“When one of the signals has happened and comes to an end, we can specifically indicate that it exactly happened at that moment in time,” says Professor Blair.
He says that until recently, all gravitational wave data analysis was retrospective.
“People working with gravity waves often recorded all their data, before analysing these long data records using very powerful computers to see if there were any ‘chirps’ or special signals present.
“As the analysis process is done a long time later, one can’t exactly tell when the signal happened,” says Professor Blair.
He says this method is also particularly unsatisfactory for detecting Gamma-ray bursts (GRBs) in gravitational waves.
“GRBs are powerful outbursts of electromagnetic energy in the universe since the big bang itself.
“Their detection will not only expose the mechanism and dynamics of the source but also allow physicists to view them with a telescope as they instantly happen.”
Professor Blair also says the particular signals the AIGRC Data Analysis team is looking for have certain patterns, comprised of frequencies that rise steadily with time.
“Our main objective is to make a device that can search for a particular pattern of frequencies and times and add them together, significantly improving sound recognition.
“We developed filters called Infinite Impulse Response Filters.
“These filters mimic the cochlea and hair cells in the human ear, which provide outputs to the thousands of parallel nerves that carry the frequency information from the ear to the brain.”
Professor Blair says that due to the rising tones of a chirp signal, each frequency occurs at a different time.
“These Infinite Impulse Response filters are able to pick out the frequencies and merge them with the appropriate time delays.”
However, he also believes that for the Infinite Impulse Response filters to work effectively, they require a massively parallel computer.
To achieve this, Professor Blair says the Infinite Impulse Response (SPIR) time delayed filter bank concept has to be combined with iVEC’s Graphics Processing Unit-enabled Fornax supercomputer.
He believes that this combination will enable physicists to detect ‘chirp’ signals more efficiently compared with previous techniques.