NASA | MSFC | SAO | Chandra X-ray Observatory | 2017 Oct 03
WISE), the ground-based Large Binocular Telescope (LBTO) in Arizona, and the Sloan Digital Sky Survey (SDSS) Mapping Nearby Galaxies at APO (MaNGA) survey. This discovery could help astronomers better understand how giant black holes grow and how they may produce the strongest gravitational wave signals in the Universe, as described in our press release.
Each pair contains two supermassive black holes weighing millions of times the mass of the Sun. These black hole couples formed when two galaxies collided and merged with each other, forcing their supermassive black holes close together. While theoretical models have predicted such giant growing black hole pairings should be relatively abundant, they have been difficult to find.
To uncover these latest supermassive black hole pairs, astronomers used optical data from the Sloan Digital Sky Survey (SDSS) — shown in the main panel of each image — to identify galaxies where it appeared that a merger between two smaller galaxies was underway. Next, they selected objects where the separation between the centers of the two galaxies in the SDSS data is less than 30,000 light years, and the infrared colors from WISE data match those predicted for a rapidly growing supermassive black hole.
Seven merging systems containing at least one supermassive black hole were found with this technique. Because strong X-ray emission is a hallmark of growing supermassive black holes, the team then observed these systems with Chandra. They found that five systems contained pairs of X-ray sources that were separated by a relatively small distance (see inset for two examples), providing compelling evidence that they contain two growing, or feeding, supermassive black holes. ...
Discovery of a dual active galactic nucleus with ~ 8 kpc separation - Sara L. Ellison et al
- Monthly Notices of the RAS: Letters 470(1):L49 (Sep 2017) DOI: 10.1093/mnrasl/slx076
arXiv.org > astro-ph > arXiv:1705.05465 > 15 May 2017
- arXiv.org > astro-ph > arXiv:1707.03921 > 12 Jul 2017