National Radio Astronomy Observatory | 2015 Sep 21
[img3="At left is the galaxy J0702+5002, which the researchers concluded is not an X-shaped galaxy whose form is caused by a merger. At right is the galaxy J1043+3131, which is a "true" candidate for a merged system. Credit: Roberts, et al., NRAO/AUI/NSF"]https://public.nrao.edu/images/non-gall ... s_nrao.jpg[/img3][hr][/hr]There may be fewer pairs of supermassive black holes orbiting each other at the cores of giant galaxies than previously thought, according to a new study by astronomers who analyzed data from the National Science Foundation's Karl G. Jansky Very Large Array (VLA) radio telescope.
Massive galaxies harbor black holes with millions of times more mass than our Sun at their centers. When two such galaxies collide, their supermassive black holes join in a close orbital dance that ultimately results in the pair combining. That process, scientists expect, is the strongest source of the long-sought, elusive gravitational waves, still yet to be directly detected.
"Gravitational waves represent the next great frontier in astrophysics, and their detection will lead to new insights on the Universe," said David Roberts of Brandeis University, lead author of the research. "It's important to have as much information as possible about the sources of these waves," he added.
Astronomers worldwide have begun programs to monitor fast-rotating pulsars throughout our Milky Way Galaxy in an attempt to detect gravitational waves. These programs seek to measure shifts in the signals from the pulsars caused by gravitational waves distorting the fabric of space-time. Pulsars are spinning, superdense neutron stars that emit lighthouse-like beams of light and radio waves that allow precise measurement of their rotation rates. ...
The Abundance of X-Shaped Radio Sources: Implications for the Gravitational Wave Background - David H. Roberts et al
- Astrophysical Journal Letters 810(1):L6 (2015 Sep 20) DOI: 10.1088/2041-8205/810/1/L6
arXiv.org > astro-ph > arXiv:1503.02021 > 06 Mar 2015 (v1), 25 Aug 2015 (v3)
- Astrophysical Journal Supplement 220(1):7 (2015 Sep 01) DOI: 10.1088/0067-0049/220/1/7
arXiv.org > astro-ph > arXiv:1503.02017 > 06 Mar 2015 (v1), 25 Aug 2015 (v3)
What X-Shaped Sources Tell Us About Gravitational Waves
AAS Nova | 2015 Sep 18