Penn researchers help ready camera that maps the sky

Recently, atop a Chilean mountain, scientists from around the world marked the dedication of the Dark Energy Camera, the most powerful sky-mapping machine ever created. The 570-megapixel camera is at the heart of the Dark Energy Survey, an international collaboration that aims to answer one of the fundamental questions about astronomy: Why is the universe expanding so quickly?

Gary Bernstein, the Reese W. Flower Professor in the Department of Physics and Astronomy, is set to travel to Chile to put the camera through its final paces as the co-leader of the Survey’s science-verification team.

While the camera took its first pictures in September, many of the telescope’s other systems and related software are only now being activated and tested. Scientists and technicians are also ironing out some physical aspects that could impact the study. For example, heat from the observatory can mix with cold air and cause localized weather that distorts images, so the researchers will practice cooling the telescope during the day so it is the right temperature to do its work at night.      

“We want to find any bugs and work through them so when we start in earnest, we know we are collecting data that’s good enough to do the science projects,” Bernstein says.

These projects present four different methods of examining the same phenomenon: The counter-intuitive finding that the expansion of the universe is accelerating, rather than slowing down due to gravity.

Project members will be looking at new supernovae, groupings of galaxies, and the way light is bent and distorted. By comparing data from these phenomena on a statistically massive scale, researchers can learn more about the force that seems to be pushing them farther and farther apart.      

With the camera scheduled to take a 600-million-pixel picture every 100 seconds for more than 500 nights, ensuring that the data-processing and analyzing software works smoothly is a high priority. The survey is slated to begin on Dec. 1.

“Every night is going to [provide] an avalanche of data,” says Bhuvnesh Jain, the Edmund J. and Louise W. Kahn Term Chair in the Natural Sciences in the Department of Physics and Astronomy and leader of the Penn contingent. Other members of the team include department chair Larry Gladney, associate professor Masao Sako, and research-staff member Mike Jarvis.

Dark Energy