Department in the News
Scientists seize rare chance to watch faraway star system evolve
March 4, 2020
Young stars are surrounded by dense disks of gas and dust the raw materials for creating planets. Over time, the disk scatters and disappears, making new planets visible to outside observers.
Credit: NASA/JPL-Caltech
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Phys.org, by Sherry Landow
At only 1% the age of the sun, the DS Tuc binary system shows us how a planet might naturally develop before its orbit is disturbed by external forces.

A young planet located 150 light-years away has given UNSW Sydney astrophysicists a rare chance to study a planetary system in the making.

"Finding young planets is challenging. We really need to understand the behavior of the parent star to be able to find the shallow signals of these planets which can be overwhelmed by starspots and flares," says Adina Feinstein, a National Science Foundation Graduate Research Fellow at the University of Chicago and co-author of the study.

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Department students: Adina Feinstein

Leftover Big Bang light helps calculate how massive faraway galaxies are
March 3, 2020
The South Pole Telescope and Dark Energy Camera provided key data for scientists to create a new method to weigh galaxy clusters.

Photo by Daniel Michalik
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UChicago News
Fermilab, UChicago scientists tap South Pole Telescope data to shed light on universe

A team of scientists have demonstrated how to "weigh" galaxy clusters using light from the earliest moments of the universe - a new method that could help shed light on dark matter, dark energy and other mysteries of the cosmos, such as how the universe formed.

The new method calculates the bending of light around galaxy clusters using the orientation of light from shortly after the Big Bang - data taken by the South Pole Telescope and the Dark Energy Camera.

"Gravitational lensing," a phenomenon in which light distorts as it's affected by the gravity of big objects like galaxies, can function as a kind of magnifying glass. It's helped scientists discover key information about the universe - but it's always been done by looking for the smearing of light around distant objects like stars.

In a study published in Physical Review Letters, Fermilab and University of Chicago scientist Brad Benson and colleagues use a different method to calculate the masses of distant galaxies: the polarization, or orientation, of the light left over from the moments after the Big Bang.

"Making this estimate is important because most of the mass of galaxy clusters isn't even visible - it's dark matter, which does not emit light but interacts through gravity and makes up about 85% of the matter in our universe," said Benson, an assistant professor in the Department of Astronomy and Astrophysics. "Since photons from the cosmic microwave background have literally traveled across the entire observable universe, this method has the potential to more accurately measure the dark matter mass in the most distant galaxy clusters."

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Department members: Bradford A. Benson, John E. Carlstrom
Scientific projects: South Pole Telescope