ESA Hubble Science Release | 2015 May 28
[img3="Illustration of galaxy with jets from a supermassive black holeIn the most extensive survey of its kind ever conducted, a team of scientists have found an unambiguous link between the presence of supermassive black holes that power high-speed, radio-signal-emitting jets and the merger history of their host galaxies. Almost all of the galaxies hosting these jets were found to be merging with another galaxy, or to have done so recently. The results lend significant weight to the case for jets being the result of merging black holes and will be presented in the Astrophysical Journal.
Credit: ESA/Hubble, L. Calçada (ESO)"]http://cdn.spacetelescope.org/archives/ ... c1511a.jpg[/img3][img3="Galaxies with relativistic jets
Credit: NASA, ESA, M. Chiaberge (STScI)"]http://cdn.spacetelescope.org/archives/ ... c1511b.jpg[/img3][hr][/hr]
A team of astronomers using the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 (WFC3) have conducted a large survey to investigate the relationship between galaxies that have undergone mergers and the activity of the supermassive black holes at their cores.
The team studied a large selection of galaxies with extremely luminous centres — known as active galactic nuclei (AGNs) — thought to be the result of large quantities of heated matter circling around and being consumed by a supermassive black hole. Whilst most galaxies are thought to host a supermassive black hole, only a small percentage of them are this luminous and fewer still go one step further and form what are known as relativistic jets. The two high-speed jets of plasma move almost with the speed of light and stream out in opposite directions at right angles to the disc of matter surrounding the black hole, extending thousands of light-years into space. The hot material within the jets is also the origin of radio waves.
It is these jets that Marco Chiaberge from the Space Telescope Science Institute, USA (also affiliated with Johns Hopkins University, USA and INAF-IRA, Italy) and his team hoped to confirm were the result of galactic mergers.
The team inspected five categories of galaxies for visible signs of recent or ongoing mergers — two types of galaxies with jets, two types of galaxies that had luminous cores but no jets, and a set of regular inactive galaxies. ...
Radio Loud AGNs are Mergers - Marco Chiaberge, Roberto Gilli, Jennifer Lotz, Colin Norman
- arXiv.org > astro-ph > arXiv:1505.07419 > 27 May 2015