My name is Evangelos Hajigabriel and I thoroughly enjoyed participating in ICRAR’s work experience program for the five days I was there.
We began work experience at ICRAR-Curtin. After showing us around the building, our supervisor, Ronniy Joseph, gave a PowerPoint presentation explaining what astronomers at ICRAR do, and he introduced us to the web-like structure formed by galaxies. Ronniy then took us to his desk and explained what his research involved. He explained his research was more maths intensive and mentioned how maths was much more enjoyable when applying it to his research rather than solving for x. We also attended Journal Club, a weekly event where the astronomers discuss recent news in astronomy and share developments in their research. At Journal Club, Rowanna (an intern from the Netherlands studying engineering) explained her modifications to the SKALA antennas to make them more efficient. After a lunch break, we talked an electrical engineer named Mia, who explained the Murchison Westfield Array (MWA). She showed us an example of the antennas used there and explained how they worked and how to put one together, as well as how collecting data works and how to point the telescopes to a particular point in the sky using delays. Mia also explained several of the problems they face with the telescopes, including lightning damage and damage from wildlife. Finally, we talked to a group of PhD students researching pulsars. They explained some of their research and taught us how to calculate the furthest distance at which something can keep up with a pulsar as it spins, this being the distance at which it must travel at the speed of light to keep up.
Our second day of work experience was at ICRAR-UWA, where we met the coordinator of the ICRAR work experience program, Greg Rowbotham. After a quick tour of the building, we talked to Kevin Vinsen, who explained the Square Kilometre Array (SKA) and introduced us to the concept of gravitational waves, which are ripples in space-time that we can detect. He also mentioned how Pythagoras Theorem is used in the theory of Relativity to describe space and time as one thing. We also talked to Luca Cortese about his research on galaxies. He explained how the youngest stars in a galaxy would appear green, not because the star itself was green but because of the hot gases surrounding the star. He showed us how it is now possible to calculate the redshift from each part of a galaxy which tells us more about its movement, such as its rotation. Luca also explained how astronomers need to send proposals to gain telescope time because there are many astronomers seeking to use the same telescopes. We watched a video about cosmology while we ate lunch and afterwards we asked Greg questions, I was particularly interested in his explanation of how we know the universe is flat. We also talked to a PhD student named Kate, whose research involved simulations and theoretical astronomy. She told us about building galaxies in simulations and modelling galaxy kinematics, and she showed us a website she created as a tool.
Again, at UWA, we began the day by talking to an astronomer named Pascal Elahi about his work in simulations, which involves constructing virtual universes. He programs a starting point in a stage of the Big Bang, codes in physics and from there simulates phenomena such as the formation of galaxies. This gets tricky when dealing with things we have a limited understanding of, such as dark matter and dark energy. Next, we spoke with Robin, a PhD student whose research involved studying how galaxies die. He explained how elliptical galaxies tend to produce fewer stars and contain mainly older stars, as oppose to disc galaxies, which contain many young stars. He mentioned how although there was a correlation, one did not necessarily cause the other.
Day 4 we were back at ICRAR-Curtin and we started by talking to a PhD student named Alex about his research on cosmic waves. He explained how he detected cosmic rays by detecting radio emissions produced by cosmic rays colliding with the atmosphere. He said that when he received information it was often converted from time-based data to frequency-based data and that for his research he needed time-based information. Next, we talked to Steve about imaging satellites using difference imaging. He told us that we can detect satellites even though they don’t emit radio waves because FM radio waves reflect off the satellites and back to Earth and about how it’s important to track satellites to make sure that they don’t collide with each other or with space junk. We also talked to Teresa, who created a board game to show how it takes a very long time for light to travel from the core of stars to the outside because it reflects off many particles in the star. She had tried to simulate this game using Python but had encountered a bug where the program was producing negative numbers. Our task was to fix this bug, which we did by comparing similar parts of code to see what was wrong. After this, Pikky Atri, one of our supervisors, told us about her research on black holes and their birth. She explained how black holes could form from either a supernova or a direct collapse. Black holes that formed from a supernova will often be knocked off their current orbit whereas black holes that formed from a direct collapse will continue to move in conjunction with their galaxy, so by studying a black hole’s movement we can determine how it formed. We later did this with some of Pikky’s data.
For our final day of work experience, we were back at UWA. To begin, Paul (who is in charge of the Spirit Telescopes) took us up to see the Spirit Telescopes on the roof of the physics building at UWA. He explained how the telescopes work and how they doesn’t take colour pictures because that makes decreases the accuracy in the data, however they can create colour images because the telescopes also have green, red and blue filters, and these can be layered on to produce a coloured image. Next, we talked to an associate professor name Chris, a theoretical astronomer who supervises the PhD students who work with simulations. He told us about how spirals form in galaxies due to differential rotation and about how stars mainly form in clusters. He explained how in the web-like structure galaxies form, there are galaxy clusters that tend to contain mainly elliptical galaxies. Chris also told us about how hot winds from moving galaxies cause gases to be ejected in the opposite direction of movement. After this, we attended Plot of the Week, a competition held by the PhD students where they explained their plots and we voted on whose was best. The winner gets to keep a shirt for the week as a prize. After lunch, Greg walked us through finding the mass of a galaxy using a hydrogen spectrum and the velocity of the galaxy. He then spent some time answering any questions we had.
Overall, I thoroughly enjoyed this wonderful experience and I would strongly recommend it to anyone interested in astronomy.