James Webb Space Telescope survey reveals fewer supermassive black holes than presumed

A College of Kansas survey of a swath of the cosmos utilizing the James Webb House Telescope has revealed energetic galactic nuclei (AGN)—supermassive black holes which are quickly rising in dimension—are rarer than many astronomers had assumed beforehand.

The findings, made with the JWST’s Mid-Infrared Instrument (MIRI), recommend our universe could also be a bit extra secure than was supposed. The work additionally provides insights into observations of faint galaxies, their properties and challenges in figuring out AGN.

A brand new paper detailing the JWST analysis, carried out underneath auspices of the Cosmic Evolution Early Launch Science (CEERS) program, was made obtainable on arXiv upfront of formal peer assessment publication in The Astrophysical Journal.

The work, headed by Allison Kirkpatrick, assistant professor of physics & astronomy at KU, centered on a long-studied zone of cosmos dubbed the Prolonged Groth Strip, positioned between the Ursa Main and Boötes constellations. However earlier examinations of the realm relied on a much less highly effective era of space telescopes.

“Our observations had been taken in final June and December, and we had been aiming to characterize how galaxies seemed throughout the heyday of star formation within the universe,” Kirkpatrick mentioned. “This can be a look again in time of seven to 10 billion years up to now. We used the mid-infrared instrument on the James Webb House Telescope to have a look at dust in galaxies which are present 10 billion years up to now, and that dust can cover ongoing star formation, and it could cover rising supermassive black holes. So I carried out the primary survey to seek for these lurking, supermassive black holes on the facilities of those galaxies.”

Whereas each galaxy encompasses a supermassive black hole on the center, AGN are extra spectacular upheavals actively drawing in gases and exhibiting a luminosity absent from typical black holes.

Kirkpatrick and lots of fellow astrophysicists anticipated that the higher-resolution JWST survey would find many extra AGN than a earlier survey, carried out with the Spitzer House Telescope. Nonetheless, even with MIRI’s increase in energy and sensitivity, few extra AGN had been discovered within the new survey.

“The outcomes seemed fully completely different from what I had anticipated, resulting in my first main shock,” Kirkpatrick mentioned. “One important revelation was the shortage of quickly rising supermassive black holes. This discovering was prompting questions in regards to the whereabouts of those objects. Because it seems, these black holes are possible rising at a slower tempo than beforehand believed, which is intriguing, contemplating the galaxies I examined resemble our Milky Way from the previous. Earlier observations utilizing Spitzer solely allowed us to check the brightest and most large galaxies with quickly rising supermassive black holes, making them simple to detect.”

Kirkpatrick mentioned an necessary thriller in astronomy lies in understanding how typical supermassive black holes, corresponding to these present in galaxies just like the Milky Way, develop and affect their host galaxy.

“The examine’s findings recommend that these black holes should not rising quickly, absorbing restricted materials, and maybe not considerably impacting their host galaxies,” she mentioned. “This discovery opens up an entire new perspective on black-hole development since our present understanding is essentially primarily based on essentially the most large black holes within the greatest galaxies, which have important results on their hosts, however the smaller black holes in these galaxies possible don’t.”

One other shocking consequence was the dearth of dust in these galaxies, mentioned the KU astronomer.

“By utilizing JWST, we will determine a lot smaller galaxies than ever earlier than, together with these the dimensions of the Milky Way and even smaller, which was beforehand inconceivable at these redshifts (cosmic distances),” Kirkpatrick mentioned. “Usually, essentially the most large galaxies have considerable dust on account of their fast star formation charges. I had assumed that decrease mass galaxies would additionally include substantial quantities of dust, however they didn’t, defying my expectations and providing one other intriguing discovery.”

In response to Kirkpatrick, the work modifications understanding of how galaxies develop, notably regarding the Milky Way.

“Our black hole appears fairly uneventful, not displaying a lot exercise,” she mentioned. “One important query concerning the Milky Way is whether or not it was ever energetic or went by way of an AGN phase. If most galaxies, like ours, lack detectable AGN, it might suggest that our black hole was by no means extra energetic up to now. Finally, this data will assist constrain and measure black hole lots, shedding mild on the origins of black holes rising, which stay an unanswered query.”

Kirkpatrick just lately earned important new time on JWST to hold out a bigger survey of the Prolonged Groth Strip area with MIRI. Her present paper included about 400 galaxies. Her upcoming survey (MEGA: MIRI EGS Galaxy and AGN survey) will embody about 5,000 galaxies. The work is deliberate for January 2024.