What poetic description is used for the variable X-ray output of M31's black hole observed over fifteen years?

Answer

"Winking" at us

The significant variability observed in the X-ray output emanating from the black hole's vicinity over the past fifteen years has led to the black hole being described poetically as 'winking' at us.

What poetic description is used for the variable X-ray output of M31's black hole observed over fifteen years?
SpaceAndromedagalaxyblack hole