NASA researchers have uncovered a perplexing case of a black hole that appears to be “tipped over,” rotating in an unexpected direction relative to the surrounding galaxy. The discovery, involving the galaxy NGC 5084, was made possible by new analysis techniques applied to archival data from the Chandra X-ray Observatory. The galaxy, known for years, revealed a hidden secret in its core thanks to advanced methods developed at NASA’s Ames Research Center in California.
Astronomers, led by Alejandro Serrano Borlaff, used a new technique to detect faint X-ray emissions in the Chandra data. Their investigation led to the discovery of four long plumes of hot, charged gas, or plasma, emanating from the galaxy. Two plumes extend vertically above and below the galaxy’s plane, while a second, unexpected pair forms an “X” shape within the plane. This unusual feature, with two sets of plumes, is a rare phenomenon in galaxy observations.
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| The Hubble Space Telescope image of NGC 5084’s core reveals a dark, vertical line, indicating a dusty disk orbiting the center, suggesting a supermassive black hole. Both the disk and black hole are tipped over, aligning at a 90-degree angle to the galaxy’s horizontal orientation. |
The peculiar structure of NGC 5084 offered strong evidence of a supermassive black hole at its center. Further analysis, incorporating data from NASA’s Hubble Space Telescope and the ALMA observatory in Chile, revealed another unexpected characteristic: a small, dusty inner disk around the black hole that rotates at a 90-degree angle to the galaxy’s overall spin. This “sideways” rotation confirmed the black hole’s tilted position, providing key insights into the galaxy’s complex history.
The use of multiple telescopes and wavelengths of light—from visible to radio waves—allowed the team to build a comprehensive picture of the galaxy. “It was like seeing a crime scene with multiple types of light,” said Borlaff, the lead scientist on the study. “Putting all the pictures together revealed that NGC 5084 has changed a lot in its recent past.”
The presence of the two pairs of X-ray plumes indicates that a significant event has disrupted the galaxy’s normal structure. Possible explanations for the galaxy’s unusual configuration include a past collision with another galaxy or the formation of a superheated gas chimney breaking out of the galactic plane.
This unprecedented discovery was made possible by archival data spanning nearly three decades, paired with novel analysis methods. The paper detailing the findings was published in The Astrophysical Journal on December 18, 2024. The image analysis technique, named Selective Amplification of Ultra Noisy Astronomical Signal (SAUNAS), was also described in the journal earlier this year.
As researchers continue to investigate, the study of NGC 5084 promises to shed new light on the dynamic processes shaping galaxies and black holes across the universe.