Looking back in time with MeerKAT
2011-04-06 14:40
Cape Town - One of the first primary investigators is looking forward to getting first crack at working on the MeerKAT (Karoo Array Telescope) once it's commissioned.
"The SKA [Square Kilometre Array] would be excellent, but MeerKAT would be brilliant in itself. It would be the most sensitive radio interferometer in the southern hemisphere," astronomer Dr Sarah Blyth told News24.
Blythe will, with Dr Andrew Baker of Rutgers University and Dr Benne Holwerda of the European Space Agency, lead a team of 56 to study the prevalence of neutral Hydrogen in the universe. Their research hopes to explain the decline in star formation in galaxies.
"We want to go back to about half the age of the universe - about six to eight billion years - and we'll be able to measure the gas from the most distant galaxies."
The MeerKAT was originally proposed as a test-bed for South Africa's bid to host the SKA, but researchers soon noted that it would be an effective instrument in itself.
Cosmology models
It will consist of 64 linked radio telescopes near Carnarvon in the Northern Cape province. Currently, seven telescopes have been built as engineers refine the design and technology to drive the industrial roll-out of the instrument.
Science and technology minister Naledi Pandor has referred to it as "our grand challenge" and the area has been designated a radio reserve by the Astronomy Geographic Advantage Act of 2007 which prohibits any activity that may impact on the quality of the observatory.
Blythe and the team are planning to look further back in time than the current record of three billion years to refine cosmology models and compliment existing science.
"We want to measure the neutral hydrogen in galaxies at high redshift, because stars are made of hydrogen. We have more elliptical galaxies today than in the past, and it's linked to how much gas there is in the galaxies.
"Earlier in the universe, the star formation rate was much higher," Blyth said.
On Earth, hydrogen is usually found in molecular form, but in space, it is found both in this form and as single atoms. This atomic form of hydrogen emits the radio waves they hope to measure with the MeerKAT, Blyth explained.
Her study, though, will require lots of time because the galaxies are so far away.
Data
"We'll stare at one patch of sky for about 4 000 hours. It's called the Extended Chandra Deep Field-South and there are two parts to the survey.
We'll observe some galaxies and compare that to all the other data we have, and on the other side, there'll be galaxies we don't see, but know are there. We'll take all those galaxies and put their signal together and get an average amount of Hydrogen in galaxies," Blyth said.
The Extended Chandra Deep Field-South is a patch of sky about the size of the quarter moon when observed from earth.
Blythe had some concerns about how the massive amount of data would be processed, but added that she was certain the engineers have planned for the maintenance of data management tools.
"The amount of data flowing through the SKA will be 250 times the total information flowing through the internet today. It will push the boundaries of computing and on the storage of data. The SKA will collect more data in a week than human kind has collected in its entire history," said SA SKA project director Dr Bernie Fanaroff.
The MeerKAT is slated to be ready by 2016, and Blythe said the most surprising thing in the survey would be to discover something that contravenes current thinking about Hydrogen in the universe.
"If we measure no difference going back in time, that would be weird."
- Follow Duncan on Twitter
