Observe the disk of light around the black hole

For the first time, an international research team found a way to observe gradual accretion disks around the black hole and verify that their electromagnetic spectrum matched what astronomers had long predicted.

It is thought that the black hole and the accretion disk gradually form a quasar, a strong light source in the center of distant galaxies. Using polarized light filters, the team, including Robert Antonucci and Omer Blaes, two physics professors at the University of California, Santa Barbara, isolated the light emitted by the accretion disk from light created. out by other matter in the vicinity of the black hole.

Antonucci said: 'This research has significantly strengthened the evidence for explanation of quasars'.

Quasars are the brilliant nuclei of distant galaxies , which are located in the central region where supermassive black holes can accumulate enough energy to light thousands of times brighter than the sun. These huge energies are filled with interstellar gas, thought to be attracted to the black hole from the surrounding 'accretion disks' . New research verifies a long-standing prediction of intense radiation emitted by gradual accretion disks.

According to Antonucci, the physical process that astronomers consider to be the most appropriate to explain the energy of quasars and the light produced includes matter falling towards the supermassive black hole and whirling around a disc. when approaching the cosmic horizon - the spherical surface marks the boundary of the black hole. In the process, friction causes the material to heat up and produce light with all wavelengths of the spectrum, including infrared, visible rays, and ultraviolet rays. Eventually, matter falls into the black hole and thus increases the size of the black hole.

The polarized light filter is attached to the telescope, which removes light from the dust particles and ionized gas clouds around the quasar, thus showing its true electromagnetic spectrum.(Photo: Makoto Kishimoto, cloud photo: Schartmann)

Antonucci said: 'If that is true, we can predict from the laws of physics the electromagnetic spectrum of quasars' . However, predictive testing is still impossible until now because astronomers have not been able to distinguish between light emitted from accretion disks and light from dust particles and impulse ionized clouds. around the black hole.

By attaching a polarized light filter to the UK Infrared Telescope (UKIRT) in Mauna Kea, Hawaii, the team, led by astronomer Makoto Kishimoto, is accompanied by Max Radio Astronomy Academy -Plank and a postdoctoral researcher at UCS, excluded other unrelated light and measured the spectrum of the accretion disk. They demonstrated that the measured spectrum matches what is expected. The researchers also used extensive data collected from the polarization analyzer of the Very Large Telescope, the observatory in Chile operated by the European space observatory.

The polarized light filter can produce results because straight light is not polarized - meaning that it has no orientation arrangement of the electromagnetic field. The accretion disk gradually emits straight light , so does the dust and ionizing gas particles. However, there is a small amount of light from the accretion disk, which is the light that researchers want to analyze, reflected with gas located very close to the black hole. That light is polarized.

Antonucci said: 'So if we only recognize polarized light, it seems that other light does not exist and we can analyze the spectrum of the accretion disk. With this knowledge we have a deeper understanding of how black holes attract matter and then expand. '

Studying the spectrum of objects such as quasars provides astronomers with a wealth of information about their properties and processes. Antonucci emphasized: 'Our understanding of the processes in the accretion disk is still limited, but at least so far we can have certain knowledge of the overall picture'.

Refer
Kishimoto et al.The characteristic blue spectra of accretion disks in quasars as uncovered in the infrared.Nature, 2008;454 (7203): 492 DOI: 10.1038 / nature07114