Monday, February 26, 2018

ALMA Observes Gaseous Torus Around Black Hole

Image: Artist's Impression of torus via ALMA / ESO / NAOJ / NRAO
Image: Artist's Impression of torus via ALMA / ESO / NAOJ / NRAO


 Astronomers using the Atacama Large Millimetre/submillimetre Array (ALMA) have spotted a rotating, dusty, gaseous torus around the central supermassive black hole of the spiral galaxy Messier 77.
 To figure out how the size of a host galaxy, often tens of billions of times bigger, is correlated to the size of its central black holes, Dr. Masatoshi Imanishi from the National Astronomical Observatory of Japan and co-authors decided to observe the centre of Messier 77.
 The galaxy's central region is an active galactic nucleus (AGN). This means that matter is constantly falling toward the black hole and emitting intense light. AGNs are important to researchers as they strongly affect the environment around themselves.

Image: Messier 77 via ALMA / ESO / NAOJ / NRAO / Imanishi et al / NASA / ESA / Hubble / A. van der Hoeven
Image: Messier 77 via ALMA / ESO / NAOJ / NRAO / Imanishi et al / NASA / ESA / Hubble / A. van der Hoeven

 “To interpret various observational features of AGNs, astronomers have assumed rotating donut-like structures of dusty gas around active supermassive black holes. This is called the ‘unified model’ of AGN,” said Dr. Imanishi. “However, the dusty gaseous donut is very tiny in appearance. With the high resolution of ALMA, now we can directly see the structure.”
  “Previous observations have revealed the east-west elongation of the dusty gaseous torus. The dynamics revealed from our ALMA data agrees exactly with the expected rotational orientation of the torus.”

Read more about this fascinating story at: http://www.sci-news.com/astronomy/messier-77-rotating-torus-05729.html
Or read the full study at: http://iopscience.iop.org/article/10.3847/2041-8213/aaa8df/meta

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