A picture of the Andromeda galaxy on the cover of an encyclopedia started it all. Nico Cappelluti was only 7 years old, but after seeing that image of the nearest major galaxy to the Milky Way, curiosity got the best of him, and he knew astronomy would be his calling.
So he convinced his father to buy him an amateur telescope, and from the backyard of his home in Rimini, Italy, he would use the 60-millimeter instrument to study the stars.
Cappelluti would go on to study astrophysics and cosmology at the University of Bologna, becoming fascinated with supermassive black holes.
Ever since, it's been nearly a two-decades-long academic love affair with the mysterious regions of space, where the gravitational pull is so strong that nothing, not even light, can escape.
But supermassive black holes have always been shrouded in mystery. They have a mass that is millions to billions of times that of the sun. But what are their origins, and how did they get to be so enormous?
Now, Cappelluti, an associate professor of astrophysics in the University of Miami College of Arts and Sciences, has taken a giant leap toward solving that conundrum.
He is one of an esteemed group of researchers from around the world who are part of the Advanced X-Ray Imaging Satellite, or AXIS, project. Cappelluti is serving as the scientific lead for the project's first pillar—to determine the origins of supermassive black holes and how those astronomical objects grow.
"We know how smaller black holes are made—through the death of stars," Cappelluti said. "But supermassive black holes remain one of the enigmas of our universe. We know that they existed very early after the Big Bang. But there is no physical explanation as to their origin and why they grow so large. What we do know is that they're important for how galaxies evolve."
Since black holes do not emit or reflect light, they are essentially invisible to telescopes. But researchers can detect and study them through the radio waves and X-rays they emit.
And that's where AXIS will come into play. Still under development, the instrument is essentially an X-ray telescope. "Black holes are not black at all in X-ray light," Cappelluti said. With AXIS, his team will map the heavens, studying supermassive black holes from the very early universe.
"We'll look at hundreds of thousands of them," he said, noting that the scientific group within the University of Miami's Department of Physics played a critical role in shaping the science aspect of the mission.
AXIS comes at a critical juncture, as NASA's aging Chandra X-ray Observatory is now 25 years old, Cappelluti said.
Currently under development at Goddard Space Flight Center, AXIS is expected to launch from the Kennedy Space Center in Florida and will operate in low Earth orbit. "We'll have data privilege and will be guaranteed large amounts of telescope time as part of our team's mission," Cappelluti said. "And for our students, it will be an unparalleled opportunity to conduct research."
The two other pillars of AXIS will examine how gas, metals, and dust flow into, through, and out of galaxies and help determine the power sources of a variety of explosive phenomena in the cosmos.
AXIS is actually one of two proposals for missions to observe X-ray and far-infrared wavelengths of light from space recently selected by NASA for additional review. Each proposal team will receive $5 million to conduct a 12-month mission concept study, and following a detailed evaluation of those studies, the space agency expects to select one concept in 2026 to proceed with construction, with a launch slated for 2032.
The other proposal is the Probe far-Infrared Mission for Astrophysics, an observatory that would study far-infrared wavelengths, helping to bridge the gap between existing infrared observatories, such as NASA's James Webb Space Telescope, and radio telescopes.
The resulting mission will become the first in a new class of NASA astrophysics missions within the agency's long-standing Explorers Program. The new mission class, Probe Explorers, will fill a gap between flagship and smaller-scale missions in NASA's exploration of the secrets of the universe.
"NASA's Explorers Program brings out some of the most creative ideas for missions that help us reveal the unknown about our universe," said Nicola Fox, associate administrator for NASA's Science Mission Directorate. "Establishing this new line of missions—the largest our astrophysics program has ever competed—has taken that creativity to new heights."
For Cappelluti, AXIS is "the instrument of my dreams. It would," he said, "be a milestone of my career."
