NRL Press Releases
News and Media
By Cassandra Eichner, U.S. Naval Research Laboratory Corporate
Innate curiosity drove Giacintucci’s discovery. She became intrigued after reading a paper published in 2016 by Chandra expert Norbert Werner and his collaborators. Werner observed the Ophiuchus galaxy cluster with the Chandra satellite and noticed a very sharp feature that looked like a curved edge in the x-ray image of the cluster. They thought it could be the edge of a giant cavity, but could not see the whole cavity because the field of view from the telescope was too small.
“They calculated how big and how energetic the black hole outburst should have been to produce such a large cavity,” Giacintucci said. “They thought it was too high – so, they thought the edge was related to another process and not an outburst.”
Giacintucci decided to investigate. Her work observing galaxy clusters led her to examine available radio data over the past several years.
“When I looked at the low-frequency images of Ophiuchus I saw this big radio structure,” Giacintucci said. “This radio emission perfectly fills the X-ray cavity like a hand in glove, so they both have to be the result of a huge black hole outburst and not something else.”
“When Norbert Werner and collaborators published the X-ray data, they didn’t have these new sensitive radio images,” she said. “So, they dismissed the possibility that this was a black-hole-driven cavity. When we found the radio emission, then one plus one became two. It all added up. This is how we ended up discovering this dinosaur.”
The research team refers to their findings as fossils or dinosaurs because the cosmic events occurred in the past, and researchers are able to see their fading, but inactive remains in the form of electromagnetic emissions across the electromagnetic spectrum.