What happened to all the supermassive black holes? Astronomers Surprised by Web Data

The James Webb Space Telescope Survey reveals fewer supermassive black holes than assumed

A study conducted by the University of Kansas using the James Webb Space Telescope has revealed that active galactic nuclei — supersonic black holes — are increasing in size faster than many astronomers previously thought.

Findings made by JWST’s Mid-Infrared Instrument (MIRI) suggest that our universe may be a bit more stable than previously thought. The work also provides insights into observations of faint galaxies, their properties, and the challenges of identifying AGN.

Details of the study

A new paper describing JWST research conducted under the auspices of the Cosmic Evolution Early Release Science (CEERS) program has recently become available. arXiv Formal peer review precedes publication The Astrophysical Journal.

The work, led by Alison Kirkpatrick, an assistant professor of physics and astronomy at KU, focused on a long-explored region of the Universe known as the Extended Growth Strip, located between the constellations Ursa Major and Bodes. However, previous studies of the region relied on less powerful generations of space telescopes.

„Our observations were taken last June and December, and we aimed to characterize what galaxies looked like when stars were forming in the Universe,” Kirkpatrick said. „This is a view from the last 7 to 10 billion years. Using the mid-infrared instrument on the James Webb Space Telescope, we look at dust in galaxies from the last 10 billion years, and that dust can obscure star formation, and it can obscure supermassive black holes. So I undertook the first survey to look for supermassive black holes lurking at the centers of these galaxies.

We show MIRI pointing 1 (right panel) together with Spitzer/IRAC (middle) and MIPS (left) observations.
Same area. Holes show the location of detected sources in each image (MIRI region only). (IRAC) for MIPS
In the picture, the holes are 6” (2”), corresponding to the tool beam size. In the IRAC image, blue corresponds to the channel
1 (3.6 μm), green corresponds to channel 2 (4.5 μm), and red corresponds to channel 3 (5.8 μm). In the MIRI image, the 770W filter is blue, the F1000W is green, and the F1280W is red. Credit: Kirkpatrick, et al., arXiv:2308.09750

Findings and implications

Every galaxy has a magnitude black hole In between, AGN are the most spectacular wakes

Kirkpatrick and several other astrophysicists expected that the JWST survey, which has a higher resolution than previous surveys conducted by the Spitzer Space Telescope, would detect more AGN. However, even with MIRI’s increased power and sensitivity, the new survey found few additional AGN.

„The results were completely different from what I expected, which led to my first big surprise,” Kirkpatrick said. „One notable revelation is the lack of fast-growing supermassive black holes. This finding has raised questions about the location of these objects. These black holes may be growing at a slower rate than previously believed, which is intriguing, given that the galaxies I studied resemble our own. milky way from the past. Previous observations using Spitzer only allowed us to study the brightest and most massive galaxies with rapidly growing supermassive black holes.

An important mystery in astronomy lies in understanding how typical supermassive black holes, such as those found in galaxies like the Milky Way, grow and affect their host galaxies, Kirkpatrick said.

„The study’s findings suggest that these black holes did not grow rapidly, absorbed limited material, and did not significantly affect their host galaxies,” he said. „This discovery opens up a new perspective on black hole evolution, as our current understanding is mostly based on supermassive black holes in massive galaxies that have significant effects on their hosts, but smaller black holes in these galaxies may. No.”

Engineers work meticulously to fit the James Webb Space Telescope’s mid-infrared instrument into the ISIM, or Integrated Science Instrument Module, in a clean room at NASA’s Goddard Space Flight Center in Greenbelt on April 29, 2013. Space Telescope The Webb Telescope is the most powerful space telescope ever built. It will observe the most distant objects in the universe, provide images of the first galaxies and discover unexplored planets around distant stars.

Another surprising result is the absence of dust in these galaxies, the KU astronomer said.

„Using JWST, we can identify galaxies much smaller than before, including the size of the Milky Way or smaller, which was previously impossible at these redshifts (cosmic distances),” Kirkpatrick said. „Typically, massive galaxies have a lot of dust due to their rapid star formation rates. I assumed that low-mass galaxies would have a significant amount of dust, but they didn’t, defying my expectations and providing another intriguing finding.

According to Kirkpatrick, the work changes the understanding of how galaxies grow, particularly the Milky Way.

„Our black hole seems very random, not showing much activity,” he said. „A significant question about the Milky Way is whether it was ever active or went through an AGN phase. Most galaxies, like ours, have no detectable AGN, which may indicate that our black hole has never been very active in the past. Ultimately, this knowledge will help us constrain and measure black hole masses, grow and grow. sheds light on the origin of incoming black holes, which remains an unanswered question.

Reference: “CEERS Key Paper VII: JWST/MIRI Reveals a Faint Population of Galaxies at Cosmic Noon Unseen by Spitzer” by Allison Kirkpatrick, Guang Yang, Aurelien Le Bail, Greg Troiani, Eric F. Bell, Nikko J. Cleri, Elba, Steven L. Finkelstein, Nimish B. Hadi, Michaela Hirschman, Penne W. Holwerda, Dale D. Koszewski, Ray A. Lucas, Jed McKinney, Casey Popovich, Paul G. Perez-Gonzalez, Alexander M. Bagley, Emanuel Dadi, Mark Dickinson, Henry C. Ferguson, Adriano Fontana, Andrea Gracian, Norman A. Grokin, Pablo Arabel Harrow, Jayhan S. Cardaldepp, Lisa J. Kewley, Anton M. Kokemoyer, Jennifer M. Lotz, , Nor Birskal, Swara Rabindranath, Rachel S. Somerville, Jonathan R. Trump, Stephen M. Wilkins and LY Aaron Yung, submitted, The Astrophysical Journal.
arXiv:2308.09750

Kirkpatrick recently conducted a large study of the extended growth strip field with MIRI at JWST with significant new time. His current paper covers about 400 galaxies. His upcoming survey (MEGA: MIRI EGS Galaxy and AGN Survey) includes about 5,000 galaxies. Work is scheduled for January 2024.