Simulated Webb images of the quasar and the quasar surrounding the galaxy

Illustration of a quasar in the early universe. Researchers will study the galaxies surrounding three bright quasars in detail for the first time with the James Webb Space Telescope. Credit: NASA, ESA, CSA, Joseph Olmsted (STScI)

Very distant active supermassive black holes are the brightest beacons in the universe. Known as quasars, these behemoths are surrounded by equally distant galaxies. Over the past few decades, researchers have embarked on a cosmic treasure hunt and identified the three most distant quasars known in the past three years, each more than 13 billion light-years from Earth. Astronomers theorize that it may take billions of years for supermassive black holes and their accompanying galaxies to form. How is it possible that these quasars became so gigantic, with billions of solar masses, in the first 700 million years of the universe? Once you can see past their glare, what do the accompanying galaxies look like? And what do their “neighborhoods” look like?

These are questions that Xiaohui Fan and Jinyi Yang, both of the University of Arizona, and Eduardo Bañados, of the Max Planck Institute for Astronomy in Heidelberg, Germany, with an international team of astronomers, will pursue. with observations taken by the James Webb Space Telescope. “These are really valuable items,” Fan said. “We structured this program to learn everything we could think of so that our team and the larger astronomical community can fully explore these quasars.”

Webb’s sensitivity to infrared light – including mid-infrared wavelengths that can only be captured from space – will allow the team to observe these objects, whose light has traveled 13 billion miles. years and whose wavelengths have been extended from ultraviolet and visible light to infrared light. . Webb has unparalleled sensitivity and spatial resolution, which will reveal complex structures in these distant objects.

The team plans to observe and analyze the data at three scales: look closely at the quasars themselves, study stars in surrounding host galaxies after removing light from quasars, and classify nearby galaxies. . “These quasars are very special objects,” Bañados explained. “That’s why we want to provide the best possible characterization of each with Webb.”

‘Zoom’ in and out

Fan, Yang and Bañados are not wasting any opportunity: they will use almost any instrument available on Webb to observe these quasars. First, they will refine measurements of the mass of each supermassive black hole. “The existence of these black holes challenges theoretical models,” Yang said. “We want to get more precise measurements of their masses to improve our understanding of how they formed and grew so quickly.”

To increase the accuracy of existing measurements from other observatories, they will turn to spectra – data that details an object’s physical properties, including mass and chemical composition, provided by Webb’s Near Infrared Spectrograph (NIRSpec ). This will allow the team to produce more accurate black hole masses.

Then they will focus on revealing the galaxies behind the bright light of quasars. They will take very deep, detailed images of each target with Webb’s Near Infrared Camera (NIRCam), then use computer models to filter out light from the quasars of each. The final processed images will give them the first views of starlight in host galaxies. The team will also obtain spectra with Webb’s Mid-Infrared Instrument (MIRI). No one can fully predict what they will learn. Were these ancient galaxies more compact? Do their stars contain more than hydrogen and helium? Webb will certainly bring new information.

The team will also obtain spectra from quasars and their host galaxies to track the movement of gas in host galaxies and determine if active supermassive black holes are sending out hot winds that heat gas from the galaxies. Although no one can observe a complete feedback loop in real time (it takes millions of years!), they can sample what’s present with NIRSpec and start observing the connections between quasars and their host galaxies.

They will also “zoom out” to see galaxies near these quasars. Webb’s large, high-resolution observations will help the team characterize nearby galaxies using Webb’s Near-Infrared Imager and Slitless Spectrograph (NIRISS) and NIRCam.

Finally, researchers will also sample large-scale environments around quasars, gas and dust characteristics. What did the universe look like 700 or 800 million years after the big bang? It was a period known as the Age of Reionization, when the gas between galaxies was largely opaque. It wasn’t until after the first billion years of the universe that the gas became completely transparent, allowing light to travel more easily. The team will measure everything between us and the quasars with NIRSpec. “We know that these quasars existed when the universe was about fifty percent neutral,” Bañados explained. “These targets represent an important age of the universe, essentially the peak of this transition. Webb will provide further constraints on what this period looked like.”

Fan, Yang and Bañados will share the riches of this in-depth observational program by communicating data and tools to the astronomical community to accelerate global quasar research in the early universe. “Webb will help us take the next quantum leap in understanding these objects,” Fan said.

NASA’s Webb Telescope will use quasars to unlock the secrets of the early universe

Provided by NASA’s Goddard Space Flight Center

Quote: Simulated Webb images of the quasar and the galaxy surrounding the quasar (2021, December 9) retrieved January 31, 2022 from

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