The launch of NASA’s next supertelescope, the Nancy Grace Roman Space Telescope (Roman), may mean there is nowhere left for violent black holes to hide.
In fact, these cosmic cannibals may not even be able to hide from Novel at “cosmic noon,” a period in the history of the universe that occurred about 11 billion to 12 billion years ago. Studying these bloody stellar events so early in the history of the universe could help reveal how supermassive black holes It grew so big, so quickly.
Occurrences of black holes The shattered stars are called tidal disturbance events (TDE), and occur when the orbit of an unfortunate star brings it too close to the immense gravitational influence of a supermassive black hole. This simultaneously crushes and compresses the star in a process called “spaghettification,” in which plasma paste wraps around the black hole and is gradually fed toward it.
Because supermassive black holes are enveloped in a unidirectional, light-trapping boundary called the event horizon, the only way to study them is when they are actively consuming surrounding matter. This matter swirls around it in what is known as accretion disks.
However, lighter supermassive black holes do not feed voraciously, making them more difficult to investigate. That is, until a star gets too close and fragments into an incredibly bright TDE that can eclipse the combined light from every star in the supermassive black hole’s host galaxy. TDEs are most common in supermassive black holes with masses between 100,000 and 100 million suns, because supermassive black holes with masses greater than a billion solar masses tend to immediately swallow their stellar sandwiches.
Previous research has suggested that TDEs would not be common in the early universe, because the first supermassive black holes would not even have a mass 100,000 times that of the sun and therefore would not tear apart stars. However, a new study has reassessed the frequency of TDEs between 1 billion and 2 billion years after the Big Bang and found that they could be more common than previously estimated. Especially during the crowded conditions found during cosmic noon.
Scheduled to launch on August 30, 2026.Scientists hope that Roman’s High-Latitude Time Domain Survey, which will repeatedly visit a region of the sky equivalent to 90 full moons, will be a powerful tool in the search for TDE in the early universe and its subsequent study. This team estimated that Rubin will detect between thousands and tens of thousands of TDEs each year, hundreds of which date back to cosmic noon.
“The Roman Space Telescope will be transformative for transitional science [transients are astronomical events that light up the sky then fade away]”said research team leader Mitchell Karmen of Johns Hopkins University. he said in a statement. “Thanks to Roman’s high sensitivity, we can find multiple tidal disturbance events at greater distances and earlier cosmic times than ever before.”
This means that Roman is in an ideal position to solve a puzzle that has developed since his predecessor, the James Webb Space Telescope (JWST), began transmitting data to Earth in July 2022.
How could early TDEs solve the riddle of black hole growth?
At the heart of all large galaxies are supermassive black holes with masses equivalent to millions or even billions of suns. When viewed in a relatively local universe, that’s not so problematic; They have had a lot of time to grow through mergers and feeding.
However, the JWST has been routinely detecting supermassive black holes before the universe was even a billion years old. This is worrying because these early black holes would have had to go through at least a billion years of mergers and gluttonous feeding to reach the supermassive state. Scientists have two predominant theories about how this growth may have occurred.
The first suggests that supermassive black holes grow from “seeds of light,” starting with black holes with masses just a few hundred times that of the Sun and that are born from the death and collapse of massive stars.
These black holes could weigh up to a few hundred times the mass of the sun. These black holes would then merge over time and consume the surrounding gas at an incredible rate facilitating rapid growth. For this theory to be correct, each young galaxy would have to host a massive black hole at its center.
The second theory suggests that the first supermassive black holes grew from “heavy seeds” created directly from the collapse of vast clouds of primordial gas and dust. This would allow rapid growth because black holes could begin the entire process of fusion and feeding before the first stars lived and died.
However, if this were the right path, the fact that collapse events were rare would make massive black holes at the hearts of cosmic noon galaxies less common.
Because TDEs are common to less massive supermassive black holes, counting their appearance at cosmic noon could give an indication of the masses of the black holes during that epoch, the key to determining between heavy seeds and light seeds.
“Tidal disturbance events help us probe the population of light supermassive black holes, which can help us discriminate between these models,” Karmen said.
“Simply counting the number of TDEs as a function of redshift [a measure of cosmic distance]significant limitations can be placed on the million-solar-mass black hole population. “Roman will be transformative because it can probe tidal disturbance events at greater distances, so that you can observe how the TDE rate evolves over time,” said team member Suvi Gezari, an associate professor of astronomy at the University of Maryland. “Just as the JWST has transformed our understanding of distance, high redshift [very distant] galaxies“Roman is poised to transform our understanding of high redshift transients.”
The team’s research was published July 14 in The Astrophysical Magazine.
