Hubble has found a black hole disk that should be non-existent

Jul 12, 2019, 09:19 IST

Hubble finds a material disk around a starving black hole in Spiral Galaxy NGC 3147NASA/ESA

Astronomers have found a black hole disk where one shouldn’t exist using the Hubble Telescope Imaging Spectrograph (STIS).
The black hole in the NGC 3147 Spiral Galaxy may be malnutritioned but it still has a disk of material circling its gravitational field 10% faster than the speed of light.
The black hole’s disk is embedded so deep in is gravitational pull that even light is having a hard time escaping.

Ordinarily most black holes have matter circling along their borders as they pull matter in with gravitational force. But, weaker black holes that don’t have enough material to feed on, grow smaller with time and the circling disk is assumed to be absent.

But, one black hole in the NGC 3147 Spiral Galaxy, with a mass 250 times that of our Sun, is breaking that postulate.

Even though the black hole is malnutritioned and much smaller than its counterparts in more active galaxies, astronomers using the Hubble Telescope have detected a disk of gas embedded within the black hole’s gravitational field.

We thought this was the best candidate to confirm that below certain luminosities, the accretion disk doesn't exist anymore. What we saw was something completely unexpected.

Ari Laor of the Technion-Israel Institute of Technology and one of the author’s of the study.

The disc is a scaled down quasar — a celestial object that emits an exceptional amount of energy — that’s normally found in objects that are at least a 1000 times brighter.

Suffocating the light

The disk is so close to black hole’s gravitational pull that even light is having a hard time escaping — coming out as stretched wavelengths that appear red.

This is an intriguing peek at a disk very close to a black hole, so close that the velocities and the intensity of the gravitational pull are affecting how the photons of light look.

Stefano Bianchi from the Università degli Studi Roma Tre and the study’s first author

It’s also surprising that a black hole assumed to be starving is whirling material around at 10% faster than the speed of light. As the gas gets closer to Earth, it turns brighter and dimmer as it moves away — a phenomenon called relativistic beaming.

The study, published in Monthly Notices of the Royal Astronomical Society, used the Hubble Telescope Imaging Spectrograph (STIS) to prove their hypothesis around lower luminosity active galaxies and how malnourished black holes can also use gas trapped by the gravitational field to form discs of material.

See also:
Our very own black hole in the Milky Way doesn’t quite eat up ‘everything’

A black hole bigger than the sun is pulling on the fabric of space and time

The ‘fuzzy’ photo of the black hole could soon be sharp as a knife