Scientists using the Hubble Space Telescope, led by John Bahcall of the Institute for Advanced Study, Princeton, confidently expected to find host galaxies around quasars. But to their amazement, they didn't in most cases. In January 1995, they reported that most of the 14 quasars they examined did not show host galaxies, even though the faintness level they reached should have revealed such galaxies. They are baffled. Bahcall said that the discovery was "a giant leap backward" in understanding quasars.
Figure 32-21 (A): The image is a negative; the Rosat detector support was cropped off.