In this series of posts, we sit down with a few of the keynote speakers of the 230th AAS meeting to learn more about them and their research. You can see a full schedule of their talks here!
Prof. David Koo may not paint with all the colors of the wind, but he does study how galaxies change over time using all the colors of the electromagnetic spectrum.
Koo is a professor emeritus at the University of California, Santa Cruz and an astronomer at the Lick Observatory. He will be giving a plenary lecture at the AAS meeting on behalf of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) collaboration. Koo’s AAS lecture, titled “CANDELS: A Cosmic Quest for Distant Galaxies Offering Live Views of Galaxy Evolution,” will highlight some of the interesting extragalactic discoveries that CANDELS has made.
CANDELS is an imaging survey of five fields that are particularly suitable for observing high-redshift field galaxies, or galaxies that don’t belong to a galaxy cluster. These galaxies have been observed at multiple wavelengths, providing more solid measurements of galaxy masses and star formation rates. The high-resolution imaging of CANDELS also makes it ideal for studying structure formation within galaxies.
Prof. Koo’s path to CANDELS has been a long and winding road. When Koo first applied for graduate school, Berkeley sent him a letter saying “the field [of astronomy] had so few jobs that you cannot expect to continue that as a career.” He went to graduate school anyway. After only two years, Koo left to serve in the Air Force as a space systems analyst, tracking “garbage” and satellites in space. After that, he worked in industry for a year, again as a “systems analyst” in meteor-burst technology before returning to graduate school at Berkeley, where he began doing observational research on galaxy evolution for his PhD thesis.
His passion for galaxy evolution has endured for 40 years now and remains strong into retirement. Lately, he’s been using observations from CANDELS and other surveys to understand the evolution of galaxies when the universe was approximately 1/3 of its current age. These galaxies are very different from present-day galaxies: many are massive and compact, many have huge regions or “clumps” of enhanced star formation, and many are transitioning from an “active” star-forming state to a “quiescent” mode. Recently, Koo has also become interested in using machine learning as a tool to understand the physical processes that help shape these galaxies.
Koo advises students to keep their minds open about research pursuits—though originally intending to study gravity and theoretical cosmology, he fell in love with observing and caught the bug of discovery. He could not have predicted that he’d even be an astronomer with Berkeley’s letter, and certainly not an observer. He also recommends that students do their best to stay “healthy and balanced in life,” since a good work-life balance makes the demanding astronomy career much more enjoyable!
If you’re interested in learning more about Prof. Koo’s work, check out his talk at 11:40 AM on 7th June at #AAS230!