Sofia Rojas was having breakfast with her family when the long-awaited email finally landed in her inbox.
It was NASA’s James Webb Space Telescope Science Mission Office who informed her that she had been allotted 18 hours to confiscate the telescope.
“I’ve gone crazy,” said Rojas, a doctoral student at the Max Planck Institute for Astronomy in Heidelberg, Germany. “I jumped. And my family wasn’t understanding.”
Her confusion was understandable. It was March 2021 and Webb hadn’t even started yet.
But the infrared telescope was also something special on the ground with an impressive array of gold-plated hexagonal mirrors. The $10 billion instrument was built to collect the faintest light emanating from the earliest stars and galaxies.
Rojas plans to study how primitive galaxies were spread across the sky and whether mysterious things called dark matter helped shape the nascent universe. She and her team will point Webb at random spots across the sky and see what they can find.
A total of 1,172 observation proposals were submitted to the Space Telescope Science Institute (STScI), which manages the new telescope. Of these, 286 projects were selected for the first year of operation, including about 25 led by PhD students, according to Christine Chen, astronomer at STScI.
Six times larger and 100 times more powerful than the Hubble Space Telescope, Webb’s ability to observe infrared light, see through interstellar dust and detect wavelengths stretched by the expanding universe and invisible to the human eye.
Rojas knew these skills would make telescope time a hot commodity. That her proposal was accepted “just feels a bit surreal,” she said, “especially because I’m doing my PhD.”
Rohan Naidu had hoped to use the Webb for his doctoral research at the Harvard Center for Astrophysics in Cambridge, Massachusetts. He started his graduate program in 2017 and expected access to observational data, “but then there was a big, big delay,” he said.
It wasn’t the first. When NASA selected a prime contractor to build the telescope in 2003, the projected launch date was set for 2010. It was delayed several times before finally taking off from French Guiana on December 25, 2021.
That was too late for Naidu’s dissertation, which eventually explored the history of the Milky Way and how it ripped apart and absorbed other galaxies to grow to its current size. But now that Webb is in business, he can revisit his original plan to study how the first galaxies formed hundreds of millions of years after the Big Bang. He plans to study a specific part of the sky where galaxies seem to abound.
Webb will tell us “when the first lights came on in the universe,” he said.
Doing science from space is expensive. To accept a proposal, scientists must convince Webb’s keepers that their work can’t be done with telescopes on the ground.
Aliza Beverage, a UC Berkeley graduate student, spent several weeks running simulations to show that the observations she wanted to make were of ancient galaxies whose light is too weak to penetrate Earth’s Atmosphere – could not be performed with the telescopes at the WM Keck Observatory in Hawaii, the next best alternative.
The same was true for Gourav Khullarwho, along with his team, spent several sleepless nights writing a successful proposal to use the Webb telescope for a full 20 hours.
Khullar, who recently completed his PhD at the University of Chicago, aims to determine the ages of early galaxies by studying what they are made of. One of Webb’s instruments, the near-infrared spectrograph, splits light to reveal imprints of elements more common in older galaxies.
“There is no other instrument that we can use to spectrally study such early galaxies,” said Khullar, who will continue his work as a postdoctoral fellow at the University of Pittsburgh.
Its target is a galaxy called COOL J1241+2219, which appears to have grown much faster than other galaxies in the young universe.
Beverage, on the other hand, is studying why some galaxies appeared to fizzle out in those early days.
“If we look back over 10 billion years in time, we see some galaxies that are dead — they’re not forming stars anymore,” she said. “They should thrive. There is so much gas that they could form stars, but they don’t. And that is a great mystery.”
While observing time has only been granted to select groups of astronomers, access to Webb data is by no means exclusive. A series of upfront science projects will help the astronomy community understand the telescope’s observing process and data analysis techniques, and the data they generate will be made available to the public.
Kedar Phadke, a graduate student at the University of Illinois at Urbana-Champaign, is involved in one such project. It targets four galaxies “of which two are very dusty and two are not dusty and have already been observed by the Hubble Space Telescope,” he said. Observations of the latter two are used to calibrate Webb’s performance, while the dusty galaxies serve as a test of how well its infrared vision can see through dust.
While Webb can see objects billions of light-years away, it can only see a tiny portion of the sky at a time. NASA Administrator Bill Nelson likened it to observing a grain of sand held at arm’s length.
COSMOS-Webb aims to expand Webb’s vision. Over a period of 208 hours, the project will image a patch of sky called COSMOS, three times the size of the full moon.
The results will be published as a catalog for other astronomers, a project supported by Olivia Cooper, a graduate student at the University of Texas at Austin. She said she expects Webb’s images from COSMOS “will uncover questions that we don’t have yet, which is exciting.”
Cooper and others have a lot of science to look forward to, and for a long time to come. Webb reached its destination nearly a million miles from Earth with minimal course corrections, saving enough fuel to extend its mission well beyond the 10 years originally hoped.
Beverage said her advisors are part of a generation of astronomers whose careers blossomed as they made discoveries with the Hubble Space Telescope.
“I feel part of a generation that will be defined by the James Webb Space Telescope,” she said.
https://www.latimes.com/science/story/2022-07-25/new-generation-of-scientists-to-commandeer-nasa-james-webb-space-telescope A new generation of scientists gets ready to commandeer the James Webb Space Telescope