Science Pictures

Adaptive Optics with NAOS

 
NGC 1068 galaxy observed in the infrared domain
Left: Imaging wavelength K (2,2 µm) - Right: Imaging wavelength M (4,8 µm)

These images were obtained through the VLT - Chile (ESO),
equipped with the NAOS adaptive optics system and the CONICA infrared camera
(DOTA)

In the 1920's, astronomers discovered a puzzling new kind of galaxy, characterised by the extreme conditions found at their core. They called this phenomena Active Galactic Nuclei, or AGNs. The AGN model was developped on the basis of the observation of NGC 1068, some 53 million light years away from Earth. In this model, a central supermassive blackhole (with a mass of hundreds to thousands of million Suns) is responsible for the extreme conditions at the core of the galaxy. Type, size and composition of material surrounding the blackhole remain controversial.

Thanks to the NAOS adaptive optics system, new structures were identified at the very core of the galaxy. Indeed, observation in the near infrared was made possible by this system, with the unprecedented resolution of 6.5 light years per pixel (the average diameter of a galaxy is 100,000 light-years). The correction* reaches 60 to 70 % at 2.2 microns. The heart of the galaxy, much brighter than its surroundings, was used to control the adaptive optics system, allowing the correction of atmospheric turbulence.

The first results, obtained on the basis of NAOS pictures, confirmed and brought new details on what was already known from studies with other telescopes: presence of a micro-spiral structure at the north of the central source, 1200 K temperature in the core showing presence of dust during sublimation, etc.).

These results also show the presence of new structures, like the four elongated "clouds" at the northwest of the source (see picture below). They are a hint of the interaction between the jet of relativistic material coming from the core and its surroundings. The temperature of the clouds seems to indicate the presence of a new type of very tiny dust particles, probably nano-diamonds.

copyright © ONERA 1996-2006
Zoom on the northern part of the core
showing four elongated structures perfectly lined up

By Damien Gratadour
(phD student at ONERA and at the Meudon Observatory,
Optics Department (DOTA/ASO)

Glossary

*        Correction
characterization of the performance of the adaptive optics system. A 100 % correction would mean that the effects of atmospheric turbulence are totally corrected by the system.

Last Update: May 7, 2004 - © ONERA 2009 - Terms of use