New telescope looks at early universe

Courtesy of QuaD / Special to The Antarctic Sun The QUEST telescope will be placed inside the shield to the left in the Dark Sector.

By Brien Barnett Sun staff

A new telescope at South Pole Station is just weeks away from probing the universe. DASI made headlines when it became the first to detect temperature differences and later polarization in the cosmic microwave background, radiation left over from the Big Bang. The Big Bang theory states that the universe began with a period of rapid expansion called inflation, and that the universe still is expanding today somewhat like a balloon with galaxies and matter on the surface of the balloon. DASI detected remnant fluctuations in the Cosmic Microwave Background radiation from that event.

DASI answered a fundamental question about whether there was evidence for the inflationary theory, said Sarah Church, assistant professor of physics at Stanford University and member of the Kavli Institute for Particle Astrophysics and Cosmology. QUaD was built to follow up on DASI’s work, Church said. “A lot of things seemed to turn out as expected but there are some questions,” she said.

Among the question are differences in theoretical models that can only be answered with more data. QUaD will look at a small piece of the sky and analyze the data in detail to learn more about the polarization of the cosmic microwave background signal. “There’s a smaller signal we want to take a look at,” Church said.

QUaD will be pointed at a small patch of sky for the Antarctic winter. QUaD has 62 detectors that must be super-cooled to temperatures a fraction of a degree above absolute zero. That sensitivity will allow it to “see” patterns in the polarization of the patch of sky.

Church said it’s hoped that QUaD may also help shed light on the existence of the mysterious dark energy that fills most of the universe.

“It’s possible that if we can understand how inflation happened we can learn more about dark energy,” she said. Like DASI, the new telescope was placed at South Pole because it offers optimal observing conditions: long periods of observing in dark, cold conditions. It paid off that the DASI mount works well for the QUEST telescope.

The DASI experiment was wrapping up and had achieved all its science goals. Meanwhile, the QUEST team was planning to design a mount, or structure, to hold the new receiver. In a conversation with the DASI team at the University of Chicago, they discovered the telescopes were using similar mounts and so began collaborating. “That enabled us to get on the air a year earlier than planned,” she said. The project is funded by the United States and the United Kingdom. Church said both nations are interested in the same science goals. No other experiment covers the same goals and the data are of value to theorists whose models can be tested by cosmological observations, she said.

NSF-funded research in this story: Dr. Sarah E. Church, Cavli Institute for Particle Astrophysics and Cosmology at Stanford University, http://www.stanford.edu/group/quest_telescope/