Credit for NGC 4395 image: Adam Block/Mount Lemmon SkyCenter/University of Arizona. Credit for accretion disk illustration: NASA/Chandra X-ray Observatory/M. Weiss.
Gemini Focuses on a Mid-sized Galactic Black Hole
Light echo measured from the central black hole in a dwarf galaxy NGC 4395. The time delay between the continuum from the black hole’s accretion disk (blue light curve) and the hydrogen emission from orbiting gas clouds (red light curve) is measured as ~80 min., providing the light travel time from the black hole to the gas emission region.
