Hidden Heart of a Galaxy: Astronomers Detect Signs of a Sleeping Giant in NGC 4527
A team of Argentinian astronomers has taken a closer look at the spiral galaxy NGC 4527, and what they’ve found could change our understanding of this seemingly quiet cosmic neighbor. Using the powerful, upgraded Giant Metrewave Radio Telescope (uGMRT), the researchers have uncovered radio signals that hint at a dormant but powerful engine—an active galactic nucleus (AGN)—lurking at its core.
Located around 49 million light-years away in the constellation Virgo, NGC 4527 has long intrigued scientists. With a starburst-level infrared glow and three recorded supernovae, this edge-on spiral galaxy is clearly alive with activity. Yet despite its rich supply of gas and signs of past explosive events, it forms stars more slowly than expected—making it a cosmic mystery.
Could it be on the verge of a galactic awakening?
To find out, a team led by Camila Ailen Galante of the National University of La Plata aimed the uGMRT at NGC 4527, scanning the galaxy at 700 and 1,230 MHz. The result: high-resolution radio images that peer deep into its dusty heart.
Their observations revealed three compact radio sources in the central region. One, right at the galactic center, shows a non-thermal spectral signature—a classic hallmark of AGNs. The other two sources, symmetrically placed along the galactic plane, suggest a broader structure shaped by intense energy flows. Signs of polycyclic aromatic hydrocarbon (PAH) destruction in the region further hint at powerful processes at work.
Most intriguing, the data suggest a circumnuclear star-forming ring—a ring of new stars forming around the galaxy’s core. This could be caused by material falling back toward the center after being ejected by a powerful super-Eddington wind—a process consistent with past or present AGN activity.
“The AGN scenario offers a compelling explanation,” the team wrote. “A dense wind failing to escape the galaxy could dump gas back into the disk, sparking star formation in a ring-like pattern.”
But is the AGN truly active—or just a remnant of a more energetic past? That remains to be confirmed. The researchers say follow-up studies with higher resolution and long-term monitoring will be key to unlocking the full story.
One thing is clear: beneath the serene surface of NGC 4527, something powerful may be stirring.
More information: C. A. Galante et al, High resolution radio analysis of the starburst galaxy NGC 4527: signatures of an AGN core, arXiv (2025). DOI: 10.48550/arxiv.2507.02204