I was pleased to see an e-mail in my inbox Wednesday morning from Benne Holwerda, a post-doctoral fellow in astronomy at the University of Cape Town in South Africa. I wrote about his research on galaxies in the January issue of Astronomy. Benne used the Hubble Space Telescope to study a galaxy silhouetted against a more distant galaxy (image at right). It revealed some previously invisible structure at the dark outer edges of the close-by galaxy.
Anyway, I instantly responded to Benne’s openness and enthusiasm. We e-mailed back and forth until I finally was able to explain his work. I hope to write more about it in the future for the magazine.
Right now, Benne is involved in an important effort to better understand the evolution of galaxies since the Big Bang. Radio astronomy will be a key tool for listening in on the early evolution of galaxies. He and his colleagues in South Africa are competing to win the right to build a gigantic new radio telescope called the Square Kilometre Array (SKA).
Benne agreed to answer a few questions about himself and the status of the South Africa project. Embedded links in this blog will lead you to additional background information about the science mentioned in our conversation.
Pendick: Tell us about your background and what brought you to South Africa.
Holwerda: My background in astronomy is a mix between the Kapteyn Institute in Groningen in The Netherlands — a big group in radio astronomy — and the Space Telescope Science Institute (STScI) in Baltimore, where much of the science with the Hubble Space Telescope is done.
Pendick: How did you end up in South Africa?
Holwerda: Well, there is a big push to get the Square Kilometre Array built here. The main competition is from Australia. So the South African government is building up the astronomical community here and building a big telescope: the MeerKAT.
The instrument is close to three times the size of the current Very Large Array in New Mexico. The idea is to show that South Africa both has the technical expertise and the drive to pull off a big scientific project. And astronomy is a great science to make an impact in — the southern sky is still much less explored than the northern one.
My immediate boss, Erwin de Block, got headhunted for this project, and the postdoc in the bargain is me. I could not pass up the opportunity to live someplace completely different as well as work on an emerging big project like this.
Pendick: Could you tell us about MeerKAT? What will be its capabilities and basic goals, and where is the project right now?
Holwerda: The MeerKAT's strategic goal is to get South Africa the SKA contract. The science goals are being worked out right now, since we are in the middle of finalizing the configuration.
That last part is important because it matters a lot how you spread out the antennas in a radio telescope. A big spread? Great for work on distant mazers. All clumped together? Good for radio continuum.
The group here at the University of Cape Town is aiming to look at radio emissions from neutral hydrogen in galaxies near and far. The MeerKAT will be pretty much ideal for that. But we are still fine-tuning where we are putting all those dishes.
The MeerKAT will be 80 dishes with a diameter of 12 meters in the Karoo Desert, northeast of Cape Town. The South African government has put into law a radio reserve especially for this project. This legal protection of the radio waves, and the fact that the Karoo is ringed by mountains blocking much interference, makes the MeerKAT ideally positioned for some unspoiled observing.
Pendick: I’m not totally clear yet on the relationship between MeerKAT and SKA. Is the former part of the latter?
Holwerda: The Square Kilometre Array is the huge new radio telescope to be built by a consortium of countries (mainly the United States and the European Union). The consortium is looking for a good radio-quiet place to put this new telescope, and South Africa and Australia are the two remaining sites. Both countries are trying to build smaller-scale telescopes to show their expertise and suitability.
Right now, the SKA will be a completely new telescope, but the SKA design is currently still very fluid. The innovation of SKA is both its size (a square kilometer of receiving area) and the fact that it will operate over pretty much all radio frequencies. It is spread out, too. If it is built in South Africa, substations will be placed as far [away] as Kenya and Madagascar.
Pendick: What’s the current status of MeerKAT? Where are you now?
Holwerda: The project is fully funded and well underway. The dish design is finalized, and the first dishes of the prototype array (KAT-7) will be set up in the next few months. The plan is to have KAT-7 and the support base fully operational by the end of 2009.
An additional cool thing is that this project comes with [scholarships] for undergrad and grad students, so a user base of South African astronomers and engineers is being built up. We just had the third conference [for these students], and it was amazing to see how large and clever this new crop of astronomers is.
Pendick: Observing the emission of neutral hydrogen is about studying the evolution of structure in the universe, right?
Holwerda: The idea is that we can see the streams of gas and structures in the large-scale structure of our universe. Current cosmology predicts, for instance, many satellites around a big galaxy. In neutral hydrogen, it could be much easier to pick these up.