New Centre for RadioCosmology improves our understanding of the cosmos

The Universe is a big place - amazingly, incredibly, vastly, and almost unimaginably big, really. And exploring and understanding its contents and history - the science of cosmology - is a big job. But the University of the Western Cape’s (UWC)  Department of Physics & Astronomy has taken a crucial step on that journey with the creation of its new Centre for Radio Cosmology (CRC).

Funded by the South African Square Kilometre Array (SKA) Project and led by UWC’s Prof Mario Santos, the new research centre aims to fully exploit the use of the next generation of radio telescopes for measurements in cosmology - in particularly with South African experiments using MeerKAT, HERA and SKA (the latter of which, when completed, will be the largest radio telescope in the world, and one of the largest and most powerful scientific projects/instruments ever).

It will focus on the development of pipelines and technical know-how in order to have a world-leading group capable of conducting the required radio surveys and tackling the huge data volumes that will be provided by these telescopes - and will ultimately provide exquisite cosmological constraints that narrow the range of research possibilities and thereby make the study of these concepts more feasible.

“A lot of preliminary work is required before we can actually deal with the real data, and the Centre will allow a coordinated team to tackle this task,” explains Prof Santos. “Once the data starts arriving, we will be in a privileged position to analyse it and provide some of the more stringent constraints on cosmology using radio telescopes.”

Prof Santos is the chair of the international SKA Science Working Group for Cosmology, and has been involved in the design process for the SKA. His team is conducting test observations with the KAT7 telescope - and soon MeerKAT - in order to test calibration techniques with real data. They are also running simulations to figure out the optimal process for cleaning measurements from contaminant signals. The simulations are run on large computer servers and generate large amounts of data that will then be processed by the team. And the CRC will also be analysing the data coming from large radio surveys in order to extract cosmological information.

“These simulations are crucial if we want to understand what we are actually going to see. When doing an observation, the telescope changes the expected signal in many different ways, and we need to understand and correct for these changes - for calibration.”

One of the main targets is a survey to measure the distribution of neutral hydrogen across cosmic timescales (what is called a HI intensity mapping survey), allowing the CRC to make a “movie” of the evolving Universe and providing detailed cosmological information.

The objective is to conduct a large survey with MeerKAT, which should provide some of the first measurements of this signal. The SKA will then provide game-changing cosmological measurements using the same type of survey.

“In particular, it will help us test the nature of dark energy (something that we also want to do with MeerKAT),” notes Prof Santos. “Also, it will tell us if there is any ‘smoking gun’ of modifications to our theory of gravity on ultra-large scales - and probe the nature of the primordial Universe.”

As if that’s not enough, parallel to this, the CRC will continuously develop and improve their theoretical understanding of cosmology, and how different theories can be tested using future experiments: “It is essential to know what questions to ask before we probe the data, so we can make sense of what we see.”

At The Centre of The Cosmological Action

By having a large team all in close proximity, the CRC will be in a unique position to process the large amount of radio data coming from these telescopes and provide cosmological constraints.

“The Centre will allow UWC to be at the leading edge of research in cosmology using radio telescopes, in South Africa and beyond,” Prof Santos says.

The UWC Astrophysics group already has a strong research body in cosmology, and Prof Santos has been focusing most of his research exactly on this interface between theory and the use of radio telescopes to do experiments in cosmology (“Something where we already are at the cutting edge, internationally,” he notes).

Some of the simulations are being developed with UWC’s Prof Romeel Dave (SARChI Chair in Cosmology), and the Centre will benefit from the resources that will be available from the Inter-university Institute for Data Intensive Astronomy (IDIA) led by UWC/UCT joint SKA Chair, Prof Russ Taylor. Further afield, there will be close interactions with the SKA SA office, and also close relations with the Rhodes Centre for Radio Astronomy Techniques and Technologies (RATT) in order to develop the telescope observation pipeline.

“This is a multidisciplinary endeavour - it’s too big and important a job for anything else,” notes Prof Santos, “and we are lucky that South Africa now has the resources to push this at the international level - and that UWC can play a leading role in the process.”

“We will be able to study the very nature of the Universe using telescopes being set in South Africa,” Prof Santos concludes. “It’s a humbling and exciting thought.”