Gravitational Waves Give Insight To Growth of Supermassive Black Holes

CSIRO Parkes Radio Telescope

Scientists are looking at gravitational waves to understand the growth of supermassive black holes.

Black holes are regions in space where gravity is so strong that nothing, not even light, can resist its pull. It is believed that every galaxy has a supermassive black hole (SMBH) in its center.

Gravitational waves can best be described as small waves or ripples that travel through the fabric of space-time. It is like putting a bowling bowl on a mattress and rolling it forward. The indentations surrounding the bowling ball as it rolls can be described as a gravitational wave.

Einstein theorized that similar to the mattress, the dimension of space-time warps and curves as planets and other objects of big masses move along it. These curvatures generate ripples (waves) in space-time that travel outward at the speed of light and diminishes in energy as it goes further out.

Although gravitational waves have not yet been directly discovered, there have been indirect observations of its existence using radio signals from a pulsar.

In this latest study, scientists believe that by studying the connection between the strength of a gravitational wave and how two colliding supermassive blackholes behave (their mass, distance between each other and how often it spirals and merge), it will help explain the growth of black holes.

Extremely Rare Gravitational Lensed Dwarf Galaxy Imaged By Hubble Space Telescope

This picture from the NASA/ESA Hubble Space Telescope shows the most distant gravitational lens yet discovered. The glow at the centre of this picture is the central regions of a normal galaxy. By chance it is precisely aligned with a much more remote, young star-forming galaxy. The light from the more distant object is bent around the nearer object by its strong graviational pull to form a ring of multiple images. The chance of finding such an exactl alignment is very small, suggesting that there may be more star-forming galaxies in the early Universe than expected.
Credit: NASA/ESA/A. van der Wel

The Hubble Space Telescope as part of the CANDELS and COSMOS survey has captured an extremely rare and very distant dwarf galaxy that is gravitationally lensed. The dwarf galaxy is a record 9.4 billion light years away. It is a young starburst galaxy that forms a perfect Einstein ring, indicating a gravitational lens with very precise alignment of the lens and the background light source.

When two objects (the light source and a lensing mass) is observed, the light from the source is bent and deflected by the gravity of the lensing mass. It allows scientists to measure the mass of the lensing mass as well as the surrounding dark matter (which does not interact with light and only can be detected by gravitational effects).

Similar to looking at an object through a wine glass, the light is bent and forms a circle which is called an Einstein ring. The lens also magnifies the background light source, acting as a "natural telescope" that allows astronomers a more detailed look at distant galaxies than is normally possible.

In the captured image, the formation of the lens is extremely rare as the alignment has a one millimeter separation at a distance of 20 kilometers - a near perfect alignment.