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Posts Tagged ‘milky way galaxy’

UCLA Astronomers Solve Puzzle About Bizarre Object At The Center Of Our Galaxy

November 3, 2014 Leave a comment

For years, astronomers have been puzzled by a bizarre object in the center of the Milky Way that was believed to be a hydrogen gas cloud headed toward our galaxy’s enormous black hole.

Having studied it during its closest approach to the black hole this summer, UCLA astronomers believe that they have solved the riddle of the object widely known as G2.

A team led by Andrea Ghez, professor of physics and astronomy in the UCLA College, determined that G2 is most likely a pair of binary stars that had been orbiting the black hole in tandem and merged together into an extremely large star, cloaked in gas and dust — its movements choreographed by the black hole’s powerful gravitational field. The research is published today in the journal Astrophysical Journal Letters.

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Hidden Nurseries In The Milky Way


APEX, the Atacama Pathfinder Experiment, is a telescope of 12 m diameter at an exceptional site on Earth: the Chajnantor plateau is located 5100 m above sea level in the Atacama desert in Chile. It was used to map the whole inner part of the plane of our Milky Way, ranging from the Southern constellations of Vela and Carina all the way to the Northern constellations of Aquila and the great Cygnus rift. The APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) mapped the Galactic Plane at a wavelength of 0.87 mm. Cold interstellar dust emits strongly in this part of the electromagnetic spectrum, called the sub-millimeter range, while it is blocking visible and infrared wavelengths. The survey has revealed an unprecedented number of cold dense clumps of gas and dust as the cradles of massive stars, thus providing a complete view of their birthplaces in the Milky Way. Based on this census, an international team of scientists led by Timea Csengeri from the Max Planck Institute for Radio Astronomy in Bonn has estimated the time scale for these nurseries to grow stars. This has been found to be a very fast process: with only 75,000 years on average it is much shorter than the corresponding time scales typically found for nurseries of lower mass stars.

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Liftoff For Europe’s Billion-Star Surveyor

December 19, 2013 1 comment

Copyright ESA–S. Corvaja, 2013

Copyright ESA–S. Corvaja, 2013

19 December 2013 ESA PR 44-2013: ESA’s Gaia mission blasted off this morning on a Soyuz rocket from Europe’s Spaceport in Kourou, French Guiana, on its exciting mission to study a billion suns.

Gaia is destined to create the most accurate map yet of the Milky Way. By making accurate measurements of the positions and motions of 1% of the total population of roughly 100 billion stars, it will answer questions about the origin and evolution of our home Galaxy.

The Soyuz launcher, operated by Arianespace, lifted off at 09:12 GMT (10:12 CET). About ten minutes later, after separation of the first three stages, the Fregat upper stage ignited, delivering Gaia into a temporary parking orbit at an altitude of 175 km.

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NASA’s Chandra Helps Confirm Evidence Of Jet In Milky Way’s Black Hole

November 21, 2013 Leave a comment

Image Credit: X-ray: NASA/CXC/UCLA/Z. Li et al; Radio: NRAO/VLA

Image Credit: X-ray: NASA/CXC/UCLA/Z. Li et al; Radio: NRAO/VLA

Astronomers have long sought strong evidence that Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way, is producing a jet of high-energy particles. Finally they have found it, in new results from NASA’s Chandra X-ray Observatory and the National Science Foundation’s Very Large Array (VLA) radio telescope.

Previous studies, using a variety of telescopes, suggested there was a jet, but these reports — including the orientation of the suspected jets — often contradicted each other and were not considered definitive.

“For decades astronomers have looked for a jet associated with the Milky Way’s black hole. Our new observations make the strongest case yet for such a jet,” said Zhiyuan Li of Nanjing University in China, lead author of a study appearing in an upcoming edition of The Astrophysical Journal and available online now.

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This Is Your Galaxy: New Data Help Astronomers Explore The Hidden Milky Way


Today, astronomers with the Sloan Digital Sky Survey III (SDSS-III) released a new online public data set featuring 60,000 stars that are helping to tell the story of how our Milky Way galaxy formed.

The highlight of today’s “Data Release 10” is a new set of high-resolution stellar spectra — measurements of the amount of light given off by a star at each wavelength — using infrared light, invisible to human eyes but able to penetrate the veil of dust that obscures the center of the Galaxy.

“This is the most comprehensive collection of infrared stellar spectra ever made,” said Steven Majewski of the University of Virginia, the lead scientist for the APOGEE project. “Sixty thousand stars is almost ten times more high-resolution infrared stellar spectra than have ever been measured before, by all the world’s telescopes. Selected from all the different parts of our galaxy, from the nearly-empty outskirts to the dust-enshrouded center, these spectra are allowing us to peel back the curtain on the hidden Milky Way.”

Full Story and Data Link: http://www.sdss3.org/press/dr10.php

NASA’s Spitzer Sees Milky Way’s Blooming Countryside

June 6, 2013 1 comment

Image credit: NASA/JPL-Caltech/University of Wisconsin

Image credit: NASA/JPL-Caltech/University of Wisconsin

New views from NASA’s Spitzer Space Telescope show blooming stars in our Milky Way galaxy’s more barren territories, far from its crowded core.

The images are part of the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (Glimpse 360) project, which is mapping the celestial topography of our galaxy. The map and a full, 360-degree view of the Milky Way plane will be available later this year. Anyone with a computer may view the Glimpse images and help catalog features.

We live in a spiral collection of stars that is mostly flat, like a vinyl record, but it has a slight warp. Our solar system is located about two-thirds of the way out from the Milky Way’s center, in the Orion Spur, an offshoot of the Perseus spiral arm. Spitzer’s infrared observations are allowing researchers to map the shape of the galaxy and its warp with the most precision yet.

While Spitzer and other telescopes have created mosaics of the galaxy’s plane looking in the direction of its center before, the region behind us, with its sparse stars and dark skies, is less charted.

“We sometimes call this flyover country,” said Barbara Whitney, an astronomer from the University of Wisconsin at Madison who uses Spitzer to study young stars. “We are finding all sorts of new star formation in the lesser-known areas at the outer edges of the galaxy.”

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2013-186

Herschel Finds Hot Gas On The Menu For Milky Way’s Black Hole


ESA’s Herschel space observatory has made detailed observations of surprisingly hot molecular gas that may be orbiting or falling towards the supermassive black hole lurking at the centre of our Milky Way galaxy.

Our local black hole is located in a region known as Sagittarius A* – Sgr A* – after a nearby radio source. It has a mass about four million times that of our Sun and lies around 26 000 light-years away from the Solar System.

Herschel has detected a great variety of simple molecules at the Milky Way’s heart, including carbon monoxide, water vapour and hydrogen cyanide. By analysing the signature from these molecules, astronomers have been able to probe some of the fundamental properties of the interstellar gas surrounding the black hole.

“Herschel has resolved the far-infrared emission within just 1 light-year of the black hole, making it possible for the first time at these wavelengths to separate emission due to the central cavity from that of the surrounding dense molecular disc,” says Javier Goicoechea of the Centro de Astrobiología, Spain, and lead author of the paper reporting the results.

The biggest surprise was quite how hot the molecular gas in the innermost central region of the Galaxy gets. At least some of it is around 1000ºC, much hotter than typical interstellar clouds, which are usually only a few tens of degrees above the –273ºC of absolute zero.

Full Story: http://www.esa.int/Our_Activities/Space_Science/Herschel/Herschel_finds_hot_gas_on_the_menu_for_Milky_Way_s_black_hole

CSI: Milky Way


Artist’s illustration. Credit: Julie Turner, Vanderbilt University

Artist’s illustration. Credit: Julie Turner, Vanderbilt University

These days the core of the Milky Way galaxy is a pretty tame place…cosmically speaking. The galactic black hole at the centre is a sleeping giant. Existing stars are peacefully circling. Although conditions are favourable, there doesn’t even seem to be much new star formation going on. But there is growing evidence that several million years ago the galactic centre was the site of all manner of celestial fireworks. A pair of assistant professors – Kelly Holley-Bockelmann at Vanderbilt and Tamara Bogdanović at Georgia Institute of Technology – has come up with an explanation that fits these “forensic” clues.

Writing in the March 6 issue of the Oxford University Press journal Monthly Notices of the Royal Astronomical Society, the astronomers describe how a single event – a violent collision and merger between the galactic black hole and an intermediate-sized black hole in one of the small “satellite galaxies” that circle the Milky Way – could have produced the features that point to a more violent past for the galactic core.

“Tamara and I had just attended an astronomy conference in Aspen, Colorado, where several of these new observations were announced,” said Holley-Bockelmann. “It was January 2010 and a snow storm had closed the airport. We decided to rent a car to drive to Denver. As we drove through the storm, we pieced together the clues from the conference and realized that a single catastrophic event – the collision between two black holes about 10 million years ago – could explain all the new evidence.”

Full Story: http://www.ras.org.uk/news-and-press/224-news-2013/2227-csi-milky-way
Also: http://news.vanderbilt.edu/2013/03/csi-milky-way/

Stellar Motions In Outer Halo Shed New Light On Milky Way Evolution

February 23, 2013 Leave a comment

Peering deep into the vast stellar halo that envelops our Milky Way galaxy, astronomers using NASA’s Hubble Space Telescope have uncovered tantalizing evidence for the possible existence of a shell of stars that are a relic of cannibalism by our Milky Way.

Hubble was used to precisely measure, for the first time ever, the sideways motions of a small sample of stars located far from the galaxy’s center. Their unusual lateral motion is circumstantial evidence that the stars may be the remnants of a shredded galaxy that was gravitationally ripped apart by the Milky Way billions of years ago. These stars support the idea that the Milky Way grew, in part, through the accretion of smaller galaxies.

“Hubble’s unique capabilities are allowing astronomers to uncover clues to the galaxy’s remote past. The more distant regions of the galaxy have evolved more slowly than the inner sections. Objects in the outer regions still bear the signatures of events that happened long ago,” said Roeland van der Marel of the Space Telescope Science Institute (STScI) in Baltimore, Md.

Full Story: http://hubblesite.org/newscenter/archive/releases/2013/07/full/

Detecting Dusty Clouds And Stars In Our Galaxy

January 11, 2013 Leave a comment

The center of our Milky Way galaxy is a wondrous place full of huge star clusters, dust clouds, magnetic filaments and a supermassive black hole. But it can be a confusing place, too, posing challenges to astronomers trying to image these exotic features and learn more about where they are located in the galaxy.

Northwestern University’s Farhad Zadeh has discovered a new tool for detecting dusty clouds and stars: simply take a picture using radio waves. He is the first to identify what he calls radio dark clouds and stars. Stars in the early and late phases of their evolution are shrouded by huge dusty envelopes in the form of dust and gas outflows.

“When you see these dark stars or clouds in radio wavelength images, it tells you something very interesting,” Zadeh said. “We immediately know there is a cold gas cloud or dusty star mixing with a hot radiative medium and that an interaction is taking place. Knowing details of these clouds is important because the clouds can produce stars and also provide material for the growth of black holes.”

Full Story: http://www.northwestern.edu/newscenter/stories/2013/01/detecting-dusty-clouds-and-stars-in-our-galaxy.html