Young Star Clusters In the Circumnuclear Region of Black Hole

In this false-colour image combining several sets of observations, the visible light is in blues (Hubble Space telescope) showing swirls of stars; the observations from NRAO's Very Large Array (VLA) radio telescope are in green and aqua displaying a central emission with two jets, and the newly discovered clusters are in red in the middle. 

The black hole is represented by a dot to show the location – the black hole itself can't be seen.

Huge young star clusters resembling a string of pearls around a black hole in the centre of a galaxy 120 million light-years away have been discovered by researchers at Swinburne University of Technology.

The galaxy, called NGC2110, is in the constellation of Orion.

Using the giant Keck telescopes in Hawaii, the researchers, Professor Jeremy Mould and PhD student Mark Durré from Swinburne's Centre for Astrophysics and Supercomputing, found four star clusters, very close (in astronomical terms) to a black hole.

"These star clusters hadn't been seen before because they are hidden by dust clouds around the black hole and because they appear very tiny, but they can be observed in infrared radiation that penetrates the clouds," Mr Durré said.

"The Keck telescopes also uses 'adaptive optics', which removes the atmospheric shimmer that blurs images."

Supermassive black holes – condensations of matter so dense that not even light can escape from its gravity – are thought to be at the centre of all large galaxies.

"Our own galaxy, the Milky Way, has a black hole that is almost four million times the mass of our Sun," Mr Durré said. "NGC2110 has a black hole about 100 times bigger."

Mark Durré

The black hole produces huge amounts of energy that comes from gas and dust falling into it.

As the material streams in, it hits an accretion disk – a spinning ring of superheated gas around the black hole's equator.

Enormous quantities of radiation shine out and some of the matter also gets spewed out in jets, which are most clearly observed by radio telescopes.

Tides from the black hole and other features of the galaxy can help form star clusters – collections of thousands of stars which are all formed together from a gas and dust cloud.

In turn, gas out-streaming from the young stars in the clusters can feed and energise the black hole.

"The jets can compress gas around them to start this star cluster formation, but they can also stop the process by blowing the gas completely out of the galaxy."

"The fine details of how the matter is funnelled in and how the black hole affects the galaxy around it remain fascinating questions for astronomers as they try to work out how galaxies form."

Mr Durré said that according to computer simulations, star clusters should form like beads or pearls on a string in a ring around the black hole – and this is just what the researchers have observed.

"After many millions of years, these clusters will be torn apart, again by tidal forces, and gradually settle into a central collection closer around the black hole." Mr Durré said.

This research has been published in the Astrophysical Journal.

More information: "Young Star Clusters In The Circumnuclear Region Of NGC 2110." Mark Durré, Jeremy Mould. arXiv:1402.3339 [astro-ph.GA]

Hubble Telescope 23rd Birthday Image: Horsehead Nebula

NASA's Hubble Space Telescope has snapped a spectacular new image of an iconic nebula to celebrate its 23 years of peering deep into the heavens.

The Hubble observatory, which launched on April 24, 1990, captured the Horsehead Nebula in infrared light, peering through obscuring veils of dust to reveal the object's hidden features.

"The result is a rather ethereal and fragile-looking structure, made of delicate folds of gas — very different to the nebula’s appearance in visible light," mission officials wrote.

The new observations allowed astronomers to create a dazzling video of the Horsehead Nebula based on Hubble's photos.

The Horsehead Nebula, also known as Barnard 33, is located about 1,500 light-years from Earth in the constellation Orion (The Hunter).

The Horsehead is a huge interstellar cloud of gas and dust, like other nebulae, and the light from a nearby star gives it a beautiful glow.

The bright stars of the Orion constellation

Head to Toe by Rogelio Bernal Andreo (USA)

The bright stars of the Orion constellation seen within a skyscape of fainter stars, gas and dust, which is invisible to the naked eye.

Orion is laid out from left to right in this photograph while a huge cloud of gas and dust in which new stars are forming lies below the three stars of Orion’s belt; bright red and blue supergiant stars mark his shoulder and knee.

The long exposure time and use of special filters allows us to see the hidden beauty behind this familiar constellation.

Picture: Rogelio Bernal Andreo

Red Super Giant Betelgeuse: Constellation Orion the Hunter

Credit: Andrea Dupree (Harvard-Smithsonian CfA), Ronald Gilliland (STScI), NASA and ESA

This image from the Hubble Space Telescope shows Betelgeuse, the red supergiant that marks the shoulder of the winter constellation Orion the Hunter (diagram at right).