Today at Berkeley Lab

Future Shines Bright for SULI Intern Zachary Raha

– By Theresa Duque

Zachary Raha was the kind of kid who always had a side project. “I would make maps of my house, my neighborhood, and the park on giant sheets of sketch paper my parents gave me,” he recalled.

Today, Raha—who recently completed a Science Undergraduate Laboratory Internship (SULI) with Nobel laureate Saul Perlmutter of the Physics Division—keeps himself busy with maps of a different scale: the expansion history of the universe as illustrated by Type Ia supernovae.

Every year, DOE’s Office of Science supports hundreds of undergraduate interns throughout the 17 national labs. At Berkeley Lab, these internships are administered by Workforce Development & Education, which hosted 15 SULI interns last fall, and 25 this spring. SULI interns get a unique opportunity to perform research under the guidance of laboratory staff scientists or engineers on projects supporting the DOE mission.

When Raha applied to the SULI program last year, he already had work experience as a research assistant for Xiaosheng Huang, an assistant professor at the University of San Francisco who specializes in observational cosmology and conducts research for the Supernova Cosmology Project, an experiment led by Perlmutter.

During his work-study with Huang, Raha developed a more efficient method for calculating models of a supernova found heavily obscured by dust. The results from that work culminated in a paper, “The Extinction Properties of and Distance to the Highly Reddened Type Ia Supernova SN 2012CU,” published in the February 20 edition of The Astrophysical Journal. At just 20 years old, Raha is the second author listed alongside Huang (first author) and an international team of researchers, including Perlmutter and Greg Aldering (pictured at left, below), also of Berkeley Lab’s Physics Division.

Last fall, after graduating from the University of San Francisco with a bachelor’s in physics and astronomy, he embarked on his first SULI internship, that one with Aldering, who leads an international experiment called the Nearby Supernova Project, or the SNfactory, which aims to develop Type Ia supernovae as “standard candles” to gauge their distance from Earth and help measure the accelerating expansion of the universe. Under Aldering’s mentorship, Raha studied an electromagnetic wave that has been contaminating supernova brightness measurements. “My job was to make a computational model that corrects that contamination,” he said.

The SNfactory observes hundreds of Type Ia supernovae from the Earth’s surface to better understand how these “standard candles” can be used as probes of cosmology, Raha explained. But clouds and other conditions of Earth’s atmosphere can dim the light from supernovae that are millions of light years away. During his spring internship with Perlmutter, Raha used image processing techniques on approximately 1 terabyte of images of 11 standard stars obtained by the SNfactory to study a new solution to this atmospheric dimming.

“To work with a dataset this massive for the first time, I had to organize my workflow in more efficient ways. This prompted me to experiment with new machine-learning techniques to parse and interpret the data,” he said.

Raha credits both of his SULI internships at Berkeley Lab for improving his communication skills through poster presentations geared toward a lay audience. “SULI gave me the unique experience of improving how I communicate with lay people,” he said. “Bridging the gap between the scientist and the general public is critical to inspiring new scientists. I encourage everyone—especially people who went to smaller schools and didn’t have a lot of faculty to do research with—to apply for these internships.”

While undergraduate students who set their sights on a career in research may consider the advantages of a SULI internship, Aldering thinks that the program benefits mentors, too. “As a researcher at a national lab, it’s really important for me to work with students like Zach who are passionate about scientific discovery and are thinking of turning that love for learning into a career,” said Aldering. “Internships through DOE’s SULI program are a very effective and rewarding way to pave the way for the next generation of scientists.”


For more information about SULI internships hosted by Workforce Development & Education at Berkeley Lab, go to, or contact them at

This work was supported in part by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS) under the Science Undergraduate Laboratory Internship (SULI).