What happened to all the supermassive black holes? Astronomers were surprised by Webb’s data

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

A University of Kansas survey of a swath of the universe using the James Webb Space Telescope has revealed active galactic nuclei — supermassive black holes that are rapidly increasing in size — that are rarer than many astronomers previously assumed.

The results, from JWST’s mid-infrared instrument (MIRI), suggest that our universe may be a little more stable than previously assumed. The work also provides insight into observations of faint galaxies, their properties, and challenges in identifying AGN.

Study details

A new paper detailing the JWST research, conducted under the auspices of the Cosmic Evolution Early Release Science (CEERS) programme, was recently made available at arXiv Before formal peer review is published in the Astrophysical Journal.

The work, led by Allison Kirkpatrick, assistant professor of physics and astronomy at KU, focused on a long-studied region of the universe called Groth’s extended bar, located between the constellations Ursa Major and Boötes. However, previous examinations of the region relied on a less powerful generation of space telescopes.

“Our observations were made last June and December, and we aimed to describe what galaxies look like during peak star formation in the universe,” Kirkpatrick said. “This is a look back in time 7 to 10 billion years in the past. We used the mid-infrared instrument on the James Webb Space Telescope to look at dust in galaxies that existed 10 billion years in the past, and this dust could mask the formation process Persistent stars, and it can hide growing supermassive black holes.So I conducted the first survey to look for these supermassive black holes lurking in the centers of these galaxies.

We show MIRI pointing to 1 (right panel) along with Spitzer/IRAC (middle) and MIPS (left) observations.
Same area. Apertures show the location of detected sources in each image (MIRI region only). For MIPS (IRAC)
In the photo, the holes are 6 inches (2 inches), which corresponds to the beam size of the device. 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

Results and implications

While each galaxy is characterized by the presence of enormous mass Black hole In the middle are more exciting active nuclei, which are more exciting disturbances that attract gas and exhibit a luminosity absent from typical black holes.

Kirkpatrick and many fellow astrophysicists expected that the high-resolution survey conducted by the James Webb Space Telescope would identify the locations of many more active active galaxies than the previous survey conducted with the Spitzer Space Telescope. However, even with MIRI’s boost in power and sensitivity, a few additional AGNs were found in the new survey.

“The results looked very different from what I expected, which led to my first big surprise,” Kirkpatrick said. “One important discovery was the scarcity of fast-growing supermassive black holes. This discovery raised questions about where these things exist. As it turns out, these black holes are likely growing at a slower pace than previously thought, which is interesting, given that the galaxies they examined It’s like our galaxy. milky way from the past. Previous observations with Spitzer have allowed us to study brighter, more massive galaxies that contain rapidly growing supermassive black holes, making them easier to detect.

Kirkpatrick said an important puzzle 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 galaxy.

She said: “The results of the study indicate that these black holes do not grow quickly, absorb limited material, and may not significantly affect their host galaxies.” “This discovery opens up a whole new perspective on black hole growth since our current understanding is largely based on the most massive black holes in the largest galaxies, which have large impacts on their hosts, but smaller black holes in these galaxies are likely to have a significant impact.” no.”

Engineers worked meticulously to implant the James Webb Space Telescope’s mid-infrared instrument at ISIM, or Integrated Science Instrument Module, in a cleanroom at NASA’s Goddard Space Flight Center in Greenbelt, Maryland on April 29, 2013. As the successor to NASA’s Hubble Space Telescope, it will 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 to form, and see unexplored planets orbiting distant stars.

The astronomer at Kuwait University said that another surprising result is the absence of dust in these galaxies.

“Using the James Webb Space Telescope, we can identify much smaller galaxies than ever before, including those the size of the Milky Way or even smaller, which was previously impossible at these redshifts (cosmic distances),” Kirkpatrick said. “Normally, the most massive galaxies have abundant dust due to their fast star formation rates. I had assumed that lower-mass galaxies would also contain large amounts of dust, but they did not, which challenges my expectations and provides another interesting discovery.”

According to Kirkpatrick, this work changes the understanding of how galaxies grow, especially with regard to the Milky Way.

“Our black hole appears to be quite calm and does not show much activity,” she said. “One important question regarding the Milky Way is whether it is active or has gone through an AGN phase. If most galaxies, like ours, lack detectable active galactic nuclei, it could mean that our black hole was not more active in the past.” Ultimately, this knowledge will help constrain and measure the masses of black holes, and shed light on the origins of black hole growth, which remains an unanswered question.

Reference: “7th major CEERS paper: JWST/MIRI reveals weak population of galaxies in cosmic noon invisible to Spitzer” by Alison Kirkpatrick, Guang Yang, Aurélien Le Bell, Greg Troiani, Eric F. Bell, Nico J. Cleary, David Elbaz, Stephen L. Finkelstein, Nimesh B. Hathi, Michaela Hirschman, Ben W. Holwerda, Dale D. Koszewski, Ray A. Lucas, Jed McKinney, Casey Papovich, Pablo J. Perez Gonzalez, Alexander de la Vega, Michaela B. Bagley, Emanuel Duddy, Mark Dickinson, Henry C. Ferguson, Adriano Fontana, Andrea Grazian, Norman A. Grojin, Pablo Arrabal Haro, Jehan S. Kartaltepe, Lisa J. Kelly, Anton M. Kokemuir, Jennifer M. Lutz, Laura Pinterici, Noor Pierzkal, Swara Ravindranath, Rachel S. Somerville, Jonathan R. Trump, Stephen M. Wilkins, L.E. Aaron Young, Lieutenant Colonel, Astrophysical Journal.
arXiv:2308.09750

Kirkpatrick recently secured significant new time at JWST to conduct a larger survey of the Extended Groth Strip field using MIRI. Her current paper included about 400 galaxies. Its upcoming survey (MEGA: MIRI EGS Galaxy and AGN Survey) will include about 5,000 galaxies. Work is scheduled to be completed in January 2024.