TAEM- The Arts and Entertainment Magazine has the pleasure of introducing Professor Steven Furlanetto of UCLA to all of our student readers. Since the beginning of adding the ‘Science section’ to our magazine, we have been able to tap into the minds of the best experts for those science students who use our publication as a learning tool for their careers.
Steven, you presently teach both astronomy and Physics at UCLA. Please tell our student readers about your formal education.
SF- I received my undergraduate degree from Carleton College, a small liberal arts school in Northfield, MN. I majored in physics there, though I took the opportunity to take a broad range of courses. After that, I won a Churchill Scholarship to study theoretical physics at the University of Cambridge for one year, where I studied the “Part III Tripos” in mathematics. Then I moved to Harvard, where I received my Ph.D.
TAEM- Prior to teaching at UCLA you also taught at several other schools. Can you tell us about this aspect of your career?
SF- After graduate school, I moved to Caltech for a postdoc. I didn’t do any classroom teaching there, but I did get the opportunity to help mentor some excellent research students. Then I moved to Yale for a brief time. I moved to UCLA five years ago.
SF- The “high-redshift universe” is just astronomy jargon for the earliest phases of the universe’s history. I’m particularly interested in the earliest phases of galaxy formation, which are known as the “cosmic dawn” – as it is these galaxies that lit up the dark universe. “Reionization” is the hallmark event of this early era. It refers to period when the light from these first generations of galaxies spread throughout the universe and ionized all the hydrogen gas that still lay in between the galaxies. We don’t know when reionization happened, as it is very difficult to observe, but we believe it occurred sometime between about 500 million and 1 billion years after the Big Bang.
SF- Although about 90% of the atoms in the universe are hydrogen, most of the rest are helium. Helium atoms are more tightly bound than hydrogen, and the first generations of galaxies cannot fully ionize helium. It therefore remains only partially ionized until much later in the history of the universe – about two billion years after the Big Bang. At that time, however, we can observe the transition in some detail. It turns out to be rather different from hydrogen reionization, but it turns out to be a useful analog in some respects.
SF- This is an exotic process that occurs within hydrogen when the electron basically flips its “spin” relative to the proton. That leads to a very slight change in the atom’s energy and the emission (or absorption) of a packet of light, called a photon. This is an extraordinarily rare event, but there is so much hydrogen in the universe that we can still use the transition to study astronomical objects. I’m interested in it as a probe of the cosmic dawn – we haven’t yet observed it in this context, but a number of experiments are just now coming online to search for it. I’m involved in one, the Murchison Widefield Array, which is under construction in the Australian outback.
TAEM- Why is the study of Structure Formation important?
SF- Structure formation refers to the story of how galaxies formed and grew from the cosmic dawn to the present day. It’s the ultimate history lesson – how the universe evolved over nearly 14 billion years! And it’s a great challenge to uncover, because of course we can’t experiment on a galaxy ten billion light years away – we just have to hope our telescopes provide enough clues to disentangle what’s going on. It’s much like archaeology in that respect.
TAEM- What is Galaxy Feedback?
SF- Galaxies are very complicated things, huge messes of stars, gas, and dust. All of that star formation has important implications for the galaxy’s environment – the photons impact nearby gas, exploding stars create “superwinds” that churn through the nearby material, and massive black holes may have even more profound effects. The feedback is the combination of all these effects on the nearby universe, and even on other components of the same galaxy. It’s the way galaxies regulate their environment, so it’s very important to the history of structure formation.
SF- This talk was an overview of my and others’ research on the first generations of galaxies. It’s a very interesting field right now, as theoretical astrophysicists are making rapid strides in understanding the sources, while real observations are on the horizon. Researchers are using some truly innovative techniques in these studies, and it’s a tremendously exciting time for all astronomers!
TAEM- What other research are you doing in these fields?
SF- Lately my big project has been writing a graduate-level textbook on the cosmic dawn, co-written with my Ph.D. advisor Abraham Loeb of Harvard. The book, The First Galaxies in the Universe, provides a comprehensive introduction to the field. It was a real challenge to write, but we hope it becomes a useful resource for the community.
SF- I received the Robert J. Trumpler prize from the Astronomical Society of the Pacific in 2006 as recognition for my PhD thesis, where I explored several ways to study the properties of the material between galaxies. The American Astronomical Society awarded me the Helen B. Warner Prize in 2011 for my work on understanding the reionization process and the 21 cm transition.
TAEM- You also proposed a project titled ‘the Dark Ages Radio Explorer’. This is an extremely interesting conception. Please tell our readers about it.
SF- This is a telescope concept, led by Jack Burns at University of Colorado, to send a radio telescope to the far side of the moon to study the earliest phases of the 21 cm background (‘dark ages’ refers to the era before the cosmic dawn). One of the challenges in these observations is radio interference from terrestrial sources, as the frequencies at which we’d like to observer are heavily used by people. It thus helps to go to the far side of the moon, where the moon itself will block the earth’s signals. The Explorer will then study the 21 cm transition from the dark ages and cosmic dawn and, we hope, provide the first evidence of the birth of stars in our universe.
TAEM- Steven, if you could suggest to NASA a possible scenario for short term, and long term, programs for space exploration, what suggestions would you make?
SF- That’s a difficult question! Given the realities of the budget these days, it’s hard to find room for a truly inspiring program. My constant concern, though, is that astrophysics will be lost in these cuts: even though science is (monetarily) a fairly small part of NASA’s budget, it’s always been the driving force for me, and I don’t want to see it get lost in the shuffle. Of course, I’d also love for NASA to return toward true exploration, whether human or robotic, of nearby bodies. There are some tremendously interesting questions you can answer about the history of our solar system, and it’s also true that this sort of exploration enables some first-rate astrophysics (like radio telescopes on the far side of the moon!).
TAEM- Steven, it has been a true pleasure to be able to introduce the many students from around the world who read our magazine. I am positive that they have learned much from your interview and you have awakened a deeper interest in science for many of them. We want to thank you for your time and hope that you will keep in touch with us about all your future work and research.