Monday, October 29, 2012

Meet Christina Williams

My name is Christina Williams, and I am a grad student in Astronomy at the University of Massachusetts in Amherst. I study galaxy evolution with CANDELS data as part of my PhD thesis. I'm working with Mauro Giavalisco as my thesis adviser, studying compact, massive, elliptical galaxies and their evolution. How and why I arrived at an astronomy department for work is in some ways similar to other astronomers, and in some ways different. Like many, I had an early fascination with the world around me, how nature works, and in particular the night sky, which is what led me here! I grew up in Washington, DC, a city full of culture and people from all over the world, but not so much in the way of nature and dark skies. I was lucky to have extremely interesting and inspiring science teachers in elementary and middle school, who showed us all sorts of fascinating gadgets in the lab and taught us about things like volcanoes and tornadoes, which you don't find in Washington. But I was especially lucky to have science teachers and advisers throughout my life, who took a special interest in my ambition to learn science, and made sure to foster it. By high school, I was convinced Astronomy was my route in life, giving in to my hunger to learn more and more fundamental aspects of science. The universe, it seemed to me, was about as fundamental as it gets!

I went to college to study Physics, not too far from home at Johns Hopkins University (JHU) in Baltimore, MD, which had a very research oriented department of Physics and Astronomy. With its location across the street from Space Telescope Science Institute, it seemed like the perfect place to be introduced to the world of astronomical research. I immediately joined a research group focused on low-mass stars and brown dwarfs, with whom I worked for all my four years there. Since JHU is a part of the Sloan Digital Sky Survey, we had loads of telescope time at its host observatory, Apache Point, in New Mexico. I traveled there several times for observing runs and also observed remotely (through a computer) from Baltimore.

Aurora Borealis over my cabin in Fairbanks, AK.
Photo credit: Christina Williams
The summer before my senior year, I decided to try something new for one summer, and received an internship studying the polar ice caps of Mars at the Geophysical Institute at the University of Alaska in Fairbanks (UAF), as part of the Research Experience for Undergraduates program (REU; see this recent blog post by a CANDELS REU student). This was an important scientific, and life changing, experience. It was there that I first learned how to make physical models with a computer, which is what many astronomers spend much of their time doing. And it was then that I fell in love with Alaska, with its big mountains, glaciers, and vast wilderness to explore. Not ready to leave Alaska, but desiring still to continue with scientific research, I took a brief hiatus from astronomy and enrolled in a masters program in Geophysics at UAF. While there, I wrote a thesis on the formation of the Arctic Ocean and its tectonic history, (something totally new for me), which is a part of the Earth that is still very poorly understood because the sea ice in the Arctic makes studying the ocean floor difficult. Living year-round in Alaska offers many exotic experiences for an exploratory spirit. Like many other Fairbanksans, I lived in a cabin without running water. There were Northern Lights to photograph, hot springs to ski to in the winter, and remote and wild rivers to float in the summer.

Fieldwork on the sea ice near Barrow, AK
I finished my masters degree mid-(academic) year, so before returning to the world of Astronomy and starting my PhD the next fall, I accepted a job with the arctic sea ice research group at the Geophysical Institute at UAF. They hired me to work with the marine radars they had set up on the Arctic coast, as part of an ice observatory, which monitors the real-time motion and other changes in the coastal sea ice. I also went to Barrow, Alaska, for fieldwork out on the ice. To get out there, we rode snow-machines on landfast sea ice (sea ice which is grounded off the coast after winter), testing the electric conductivity and albedo of the ice, and taking core samples to learn about how the ice composition changes over time. One of many goals of this constant monitoring is to learn about how the ice patterns have been changing in recent decades. This is increasingly important in part because Inupiat Eskimo communities, who have relied on knowledge of seasonal landfast ice patterns for subsistence hunting for centuries, are now faced with the need to adapt to changes in the arctic.

ASTE site, in the Atacama Desert, Chile
The next fall I started my PhD in Astronomy at UMass. The astronomy program here is structured such that you have two different research projects before choosing a thesis topic, and in this way get exposed to a variety of sub-fields within astronomy. In my first few years here, I studied sub-millimeter galaxies (SMGs), and their clustering (see this recent blog post, and also this one). These are galaxies which are so dust-obscured, they are often only observable at long wavelengths. The dust blocks and absorbs the starlight which heats the dust, and the dust re-radiates in the far-infrared part of the spectrum. By the time the light reaches us, it is red-shifted to the sub-millimeter part of the spectrum. The wavelength we observed in is 1.1 mm, and is extremely sensitive to the amount of water vapor in the atmosphere. This means observations need to be taken from extremely dry regions of the Earth. We were using a Japanese telescope located in the Atacama Desert in Chile, called the Atacama Submillimeter Telescope Experiment (ASTE), which at the time was using a sub-millimeter detector called AzTEC (acronym translation available here) that was developed here at UMass. (This detector is now in Mexico being tested on the new Large Millimeter Telescope (LMT), which will be the biggest single dish sub-millimeter telescope on Earth!) To balance all the time I end up sitting in front of a computer, I went down to Chile for observing and general observatory maintenance at ASTE for a month!

Sub-millimeter astronomy is intriguing because very little is known about the galaxies that produce this kind of light because detectors and observatories in this wavelength regime are relatively new advances in technology. So there are many unanswered questions, which hopefully other new observatories such as the Atacama Large Millimeter Array (ALMA) in the Atacama desert and the LMT in Mexico will help us understand. Part of my goal in studying clustering of SMGs was to understand if they have an evolutionary connection to massive elliptical galaxies. But the unfortunate thing about current sub-millimeter observatories is that they have very low resolution imaging, which means you rarely get to see the shape and morphology of what you're looking at in detail. Perhaps that's one of the reasons that led me to Hubble Space Telescope (HST) and working with CANDELS data for the rest of my PhD thesis. I definitely love looking at the beautiful high-resolution images from HST that show the morphologies of galaxies!

Climbing Pigeon Spire, Bugaboo Provincial Park,
British Columbia
But, I might be a pretty boring scientist if science was all I was interested in. Getting the mind off work periodically is really important, not only because we are human, but also because it allows the brain some perspective for solving problems and can result in small epiphanies. What better way to gain a little different perspective than to climb hundreds of feet off the ground? Probably my biggest passion outside of science is climbing, which I started in college, and it has taken me to remote corners of the world. But even exploring the climbing here in New England has been a wonderful opportunity, because Amherst is centrally located between many world-class climbing areas (which are much more accessible than much of the climbing in Alaska!).

Where in the world I go from here is anyone's guess! I hope to graduate soon, and find a good postdoctoral position where i can continue exploring unanswered questions about high-redshift galaxies. Some serious hurdles currently face junior astronomers on the job market. The number of PhDs in astronomy exceeds the number of available permanent positions in astronomy, so competition for jobs is fierce and the prospects can be quite daunting. Astronomers typically do two postdoctoral positions before finding a permanent position. These are things I will face soon enough. But its important to keep in mind that often a big hurdle to success is lack of confidence in ones own abilities. Among all the science I've learned in graduate school, one of the most important lessons I've learned thus far is that believing in yourself is not just a cliche phrase, but has some serious truth in it. None of us arrived where we are by doubting ourselves. And this lesson I'll take with me no matter where I go.


  1. Nice blog Christina. A big hug from Chile!

    Juan Cortes

  2. What I love about this blog is the posts written by the astronomers sharing their career insights. Great stories.