When a black hole winks at you

MSU researcher identifies variability in supermassive black hole at heart of the Andromeda galaxy

Black hole 1
X-ray data gathered by the Chandra telescope from the center of M31, highlighting the four nuclear sources — S1, SSS, N1, and P2. P2 corresponds to the position of the supermassive black hole at the center of the Andromeda galaxy. Credit: DiKerby, Zhang, & Irwin 2025, ApJ

Using NASA’s Chandra X-ray Observatory, MSU physicist Stephen DiKerby captured a rare cosmic light show coming from the Andromeda galaxy. “I had a chill, because I realized I was looking at the X-rays from a supermassive black hole flicker on and off,” he said.

With data spanning 15 years, DiKerby and his collaborators pieced together a record of X-ray light emitted from the black hole M31*. Chandra’s precision allowed this activity to be isolated from other X-ray sources crowded around Andromeda’s core—work DiKerby likens to measuring the intensity of four flickering candles at the far end of a football stadium.

The research provides insight into the unique relationship between a galaxy and its black hole. This is critical to understanding how the universe developed over the past 14 billion years.

Black hole 2
A view of the Andromeda galaxy in optical light and an enhanced, zoomed view using the XMM Newton and the Chandra telescope. Credit: Sloan Digital Sky Survey, XMM-Newton, Chandra X-ray Observatory, collected via Aladin