1. Two Supermassive Black Holes in the Same Galaxy

2. Profile of the Galaxy – NGC 6240 - Discovered by NASA’s Chandra X-ray Observatory - Nucleus of the galaxy is extraordinarily bright - 400 millions Light Year from Earth -Two black holes in the central region of the galaxy  they are 3000 Light Year apart  They are orbiting each other  Actively accreting material from their surroundings - Example of massive galaxy

3. Formation of the Galaxy - Recent collisions - Consequences of merging of two smaller galaxies (Movies of merging of two galaxies) Optical -Arcs are result of collision of two galaxies in the past X-ray - Detect two supermassive black holes

4. Observations - Chandra can distinguish two nucleus by measuring details of X-radiation from each nucleus 1.High energy X-ray emission (blue)2. Low energy X-ray emission (red) - Optical: central part is not visible in optical wavelength band (due to large amount of dust and gas in such galaxy) - X-ray: better because it is more penetrating to view the centre

5. Predictions - The two black holes will merge several hundred years later (this will be the first time we see binary black hole in action)  Create even larger black hole  Release intense radiation and gravitational waves  gravitational waves spread through the universe  LISA (Laser Interferometer Space Antenna) planned by NASA and ESA, will search this waves (movies of merging of two black holes)

6. Importance The observation of two black holes in the same galaxies: - shows black hole can grow enormous masses in the centre of galaxies by merging with other black hole - understand how galaxies form and evolve

7. http://www.mpe.mpg.de/pr20021119.html#movies Source Date: 17/12/02 Website: