The galaxy ESO 243-49 contains an object that glows brightly in X-rays (light blue object above and to the left of the galaxy in this illustration). Its X-ray output is so bright that normal stellar processes can’t explain it; researchers suspect it is a middleweight black hole weighing at least 500 times the mass of the sun (Illustration: Heidi Sagerud)
THE black hole family has a middle child, if an otherwise unexplained source of fluctuating X-rays is anything to go by.
Small black holes the size of stars and the supermassive variety are familiar, but until now there have…
