Posts Tagged ‘galaxy’

We’ve Revealed A Galaxy Far, Far Away….

BETA_snap_smThe galaxy was uncovered in radio emission travelling to Earth using CSIRO’s Australian SKA Pathfinder telescope (ASKAP), located at the Murchison Radio-astronomy Observatory (MRO).

The team used a special technique to detect a change in radio waves coming from within the bright centre of the galaxy PKS B1740-517, located near the Ara constellation.

The five-billion-year-old radio emission was stamped with the ‘imprint’ of hydrogen gas it had travelled through on its way to Earth.

The gas absorbs some of the emission, creating a tiny dip in the signal. “At many observatories, this dip would have been hidden by background radio noise, but our site is so radio quiet it stood out clearly,” Dr Allison said.

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Nearby “Dwarf” Galaxy Is Home To Luminous Star Cluster

The NGC 5253 galaxy as seen through the Hubble Space Telescope

The NGC 5253 galaxy as seen through the Hubble Space Telescope

A team of Tel Aviv University and UCLA astronomers have discovered a remarkable cluster of more than a million young stars are forming in a hot, dusty cloud of molecular gases in a tiny galaxy very near our own.

The star cluster is buried within a massive gas cloud dubbed “Cloud D” in the NGC 5253 dwarf galaxy, and, although it’s a billion times brighter than our sun, is barely visible, hidden by its own hot gases and dust. The star cluster contains more than 7,000 massive “O” stars: the most brilliant stars extant, each a million times more luminous than our sun.

“Cloud D is an incredibly efficient star and soot factory,” says Prof. Sara Beck of TAU’s Department of Astronomy and Astrophysics and co-author of the research, recently published in Nature. “This cloud has created a huge cluster of stars, and the stars have created an unprecedented amount of dust.”

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Galaxy’s Snacking Habits Revealed

Images Credit: Angel Lopez-Sanchez (AAO/MQU) and Baerbel Koribalski (CSIRO)

Images Credit: Angel Lopez-Sanchez (AAO/MQU) and Baerbel Koribalski (CSIRO)

A team of Australian and Spanish astronomers have caught a greedy galaxy gobbling on its neighbours and leaving crumbs of evidence about its dietary past.

Galaxies grow by churning loose gas from their surroundings into new stars, or by swallowing neighbouring galaxies whole. However, they normally leave very few traces of their cannibalistic habits.

A study published today in Monthly Notices of the Royal Astronomical Society (MNRAS) not only reveals a spiral galaxy devouring a nearby compact dwarf galaxy, but shows evidence of its past galactic snacks in unprecedented detail.

Australian Astronomical Observatory (AAO) and Macquarie University astrophysicist, Ángel R. López-Sánchez, and his collaborators have been studying the galaxy NGC 1512 to see if its chemical story matches its physical appearance.

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Hubble Finds Massive Halo Around The Andromeda Galaxy

University of Notre Dame astrophysicist Nicolas Lehner has led a team of scientists who have used NASA’s Hubble Space Telescope to identify an immense halo of gas surrounding the Andromeda Galaxy, the nearest major galaxy to Earth. The halo stretches about a million light-years from Andromeda, halfway to the Milky Way. The discovery will tell astronomers more about the evolution and structure of giant spiral galaxies such as the Milky Way and Andromeda.

“Halos are the gaseous atmospheres of galaxies,” said Lehner, the lead investigator. “The properties of these gaseous halos control the rate at which stars form in galaxies.” The gargantuan halo is estimated to contain at least as much mass in its diffuse gas as half of the stars in the Andromeda Galaxy.

The Andromeda Galaxy, also known as Messier 31 or M31, is the most massive galaxy in the Local Group of galaxies that also includes the Milky Way and about 45 other known galaxies. M31 contains one trillion stars, about double the number of stars in the Milky Way. It is estimated to be about 25 percent more luminous than the Milky Way and lies 2.5 million light-years away.

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Athena To Study The Hot And Energetic Universe

Artist's impression of an active galaxy. Copyright: ESA/AOES Medialab

Artist’s impression of an active galaxy. Copyright: ESA/AOES Medialab

ESA has selected the Athena advanced telescope for high-energy astrophysics as its second ‘Large-class’ science mission.

The observatory will study the hot and energetic Universe and takes the ‘L2’ slot in ESA’s Cosmic Vision 2015–25 plan, with a launch foreseen in 2028.

By combining a large X-ray telescope with state-of-the-art scientific instruments, Athena will address key questions in astrophysics, including: how and why does ordinary matter assemble into the galaxies and galactic clusters that we see today? How do black holes grow and influence their surroundings?

Scientists believe that black holes lurk at the centre of almost all galaxies and that they play a fundamental role in their formation and evolution.

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Dramatic New Portrait Helps Define Milky Way’s Shape, Contents

Credit: NASA/JPL-Caltech/University of Wisconsin-Madison

Credit: NASA/JPL-Caltech/University of Wisconsin-Madison

Using more than 2 million images collected by NASA’s orbiting Spitzer Space Telescope, a team of Wisconsin scientists has stitched together a dramatic 360-degree portrait of the Milky Way, providing new details of our galaxy’s structure and contents.

The new composite picture, using infrared images gathered over the last decade, was unveiled today at a TED conference in Vancouver. The galactic portrait provides an unprecedented look at the plane of our galaxy, using the infrared imagers aboard Spitzer to cut through the interstellar dust that obscures the view in visible light.

“For the first time, we can actually measure the large-scale structure of the galaxy using stars rather than gas,” explains Edward Churchwell, a University of Wisconsin-Madison professor of astronomy whose group compiled the new picture, which looks at a thin slice of the galactic plane. “We’ve established beyond the shadow of a doubt that our galaxy has a large bar structure that extends halfway out to the sun’s orbit. We know more about where the Milky Way’s spiral arms are.”

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The Dusty Heart Of An Active Galaxy

Credit: NASA HST, News Release STScI-2000-37

Credit: NASA HST, News Release STScI-2000-37

An international research team led by Konrad Tristram from the Max-Planck-Institute for Radio Astronomy in Bonn, Germany, obtained the most detailed view so far of the warm dust in the environment of a supermassive black hole in an active galaxy. The observations of the Circinus galaxy show, for the first time, that the dust directly illuminated by the central engine of the active galaxy is located in two distinct components: an inner warped disk and a surrounding larger distribution of dust. Most likely, the larger component is responsible for most of the obscuration of the inner regions close to the supermassive black hole. Such a configuration is significantly more complex than the simple dusty doughnut, which has been favoured for the last few decades.

In active galactic nuclei, enormous amounts of energy are released due to the feeding of the supermassive black hole in the centre of the galaxy. Such black holes have masses of a million or billion times the mass of the sun. The matter spiralling in onto the black hole becomes so hot and luminous that it outshines its entire galaxy with billions of stars. The huge amounts of energy released also affect the surrounding galaxy. Active galactic nuclei are therefore thought to play an important role in the formation and evolution of galaxies and hence in the formation of the universe as presently seen.

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