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UA astronomy soars as Webb space telescope prepares to look back in time

Black holes 'cannot hide' from James Webb Space Telescope

On Dec. 25 at 5:20 a.m., an Ariane 5 rocket roared into the sky from its launchpad in Kourou, French Guiana, with the James Webb Space Telescope stowed inside and lifting University of Arizona research to new heights. 

The Webb Telescope is one of those once-a-generation research instruments that goes live and sends the whole scientific world aflutter with anticipation. 

UA researchers are right out front.

NASA has allotted time to scientists around the world, with 13 percent of the total observing time awarded to two UA instrument teams and other UA astronomers. This gives the university more viewing time than any other astronomy center in the world.

The successful launch marked the beginning of the telescope's month-long journey to its new home and, if all goes smoothly, a new era in space observation.

Webb is NASA's top science priority and involved decades of work by thousands of scientists, engineers and managers in the U.S., Canada and Europe. UA astronomers played key roles in designing and developing the telescope's infrared eyes, which will allow it to peer deeper into the cosmos than ever before.

Webb's Near-Infrared Camera is one of the most sensitive instruments of its kind and will serve as the telescope's primary imager. UA Regents Professor of Astronomy Marcia Rieke is the camera team's principal investigator. She led the development of the instrument that Lockheed Martin's Advanced Technology Center built, designed and tested.

George Rieke, Marcia's husband and also a regents professor of Astronomy at UA's Steward Observatory, is the science team lead for the Mid-Infrared Instrument, which was built by a consortium of European scientists and engineers and NASA's Jet Propulsion Laboratory. The instrument was added to Webb to expand the telescope's reach even farther into the infrared spectrum.

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The infrared range exists beyond light visible to the naked eye on the at a longer wavelength than red and but not as long as microwave. Heat emits infrared rays.

Two other instruments, supplied by the European and Canadian space agencies, round out Webb's scientific package.

"It's incredibly exciting to have a successful launch," said Buell Jannuzi, head of the UA astronomy department and director of Steward Observatory. "I am so happy for everyone who made this possible and am looking forward to the science that will come from everyone's hard work in the months ahead."

First things first

A telescope's image clarity is determined by the size of its mirror compared to the wavelength of light it's collecting. Infrared light has longer wavelengths than visible light, so a larger mirror is needed to produce quality images. Webb's primary mirror is over two stories tall and the sunshields protecting it from the heat of the sun, Earth and moon are as long as a tennis court.

Thrusting such a large and expensive piece of equipment into space can be full of challenges, even on a rocket as large as the Ariane 5. 

NASA's trick? Fold the telescope so it fits into the nose of the rocket and unfurl it in space. Webb's primary mirror is made up of 18 foldable, gold-coated, hexagonal segments, which allow for the mirror to be nearly circular. Unfolded, the primary mirror measures more than 21 feet across.

Once Webb has completed its month-long journey to its final orbit, the Near-Infrared Camera team's first job will be to precisely align the mirror segments so they work as a unit. NIRCam, as it's known, will do this by measuring incoming infrared light and the distortions created as it encounters Webb's optics. That data will be used to properly align Webb's mirrors, a process that is critical to capturing crystal-clear images.

Cameras' focus

NIRCam was conceived to carry out Webb's original purpose: Find what astronomers refer to as "first light" galaxies at the moment of their formation in the very early universe.

"We can currently see galaxies back to 500 to 600 million years post-Big Bang, nearly 13 billion years ago," Marcia Rieke said. "I've always wanted to find the most distant galaxies and trace how galaxies changed from that epoch all the way to current times. My other goal is to look at the atmospheres of exoplanets and understand their composition."

Marcia Rieke's team members — including Assistant Research Professors Christina Williams and Kevin Hainline, Research Professor Eiichi Egami and Associate Research Professor Christopher Willmer — are working to find the first galaxies. Assistant Research Professors Thomas Beatty, Jarron Leisenringand Everett Schlawin will look at the results on exoplanet atmospheres.

While Webb will only look a bit farther than we already can see with the Hubble space telescope, it will look much closer to the Big Bang, George said.

"If you're counting from the Big Bang, it's going to get twice as close, rather than five percent further back than we have looked," he said, "and that is a very important distinction."

George Rieke's team — postdoctoral research associates Jianwei Lyu and Michael Florian, along with Assistant Research Professors Stacey Alberts and Irene Shivaei — is looking forward to understanding the origin of quasars and active galactic nuclei — the super-sized black holes that shape galaxies.

"Some of them may be so hidden in dust that they just can't be found with current observatories," he said. "But they cannot hide from Webb and its super-sensitive Mid-Infrared Instrument."

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NASA GSFC/CIL/Adriana Manrique Gutierrez

Artist conception of the James Webb Space Telescope. A tennis-court-sized shield will keep the extremely sensitive infrared detection instruments out of sun's rays.