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Posts Tagged ‘VLA’

Supernova Cleans Up Its Surroundings


Credit: X-ray: NASA/CXC/Morehead State Univ / T.Pannuti et al.; Optical: DSS; Infrared: NASA/JPL-Caltech; Radio: NRAO/VLA / Argentinian Institute of Radioastronomy / G.Dubner

Credit: X-ray: NASA/CXC/Morehead State Univ / T.Pannuti et al.; Optical: DSS; Infrared: NASA/JPL-Caltech; Radio: NRAO/VLA / Argentinian Institute of Radioastronomy / G.Dubner

Supernovas are the spectacular ends to the lives of many massive stars. These explosions, which occur on average twice a century in the Milky Way, can produce enormous amounts of energy and be as bright as an entire galaxy. These events are also important because the remains of the shattered star are hurled into space. As this debris field – called a supernova remnant – expands, it carries the material it encounters along with it.

Astronomers have identified a supernova remnant that has several unusual properties. First, they found that this supernova remnant – known as G352.7-0.1 (or, G352 for short) – has swept up a remarkable amount of material, equivalent to about 45 times the mass of the Sun.

Another atypical trait of G352 is that it has a very different shape in radio data compared to that in X-rays. Most of the radio emission is shaped like an ellipse, contrasting with the X-ray emission that fills in the center of the radio ellipse.

A recent study suggests that, surprisingly, the X-ray emission in G352 is dominated by the hotter (about 30 million degrees Celsius) debris from the explosion, rather than cooler (about 2 million degrees) emission from surrounding material that has been swept up by the expanding shock wave. This is curious because astronomers estimate that G352 exploded about 2,200 years ago, and supernova remnants of this age usually produce X-rays that are dominated by swept-up material. Scientists are still trying to come up with an explanation for this behavior.

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Watching For A Black Hole To Gobble Up A Gas Cloud


Simulation. Image by ESO/MPE/Marc Schartmann

Simulation. Image by ESO/MPE/Marc Schartmann

Right now a doomed gas cloud is edging ever closer to the supermassive black hole at the center of our Milky Way galaxy. These black holes feed on gas and dust all the time, but astronomers rarely get to see mealtime in action.

Northwestern University’s Daryl Haggard has been closely watching the little cloud, called G2, and the black hole, called Sgr A*, as part of a study that should eventually help solve one of the outstanding questions surrounding black holes: How exactly do they achieve such supermassive proportions?

The closest approach between the black hole and gas cloud is predicted to occur any day now. Haggard has been using two world-class observatories, the Chandra X-ray Observatory and the Very Large Array, to gather data on this potentially spectacular encounter.

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Surprising Image Provides New Tool For Studying A Galaxy

November 15, 2013 Leave a comment

Credit: Jayanne English (U. of Manitoba), Judith Irwin (Queen's U.), Richard Rand (U. of New Mexico) and collaborators in the CHANG-ES consortium, NRAO VLA, NASA WISE & Spitzer missions, NOAO, and SDSS.

Credit: Jayanne English (U. of Manitoba), Judith Irwin (Queen’s U.), Richard Rand (U. of New Mexico) and collaborators in the CHANG-ES consortium, NRAO VLA, NASA WISE & Spitzer missions, NOAO, and SDSS.

Astronomers studying gas halos around nearby galaxies were surprised when detailed studies with the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) showed that one of their subjects is not a single galaxy, but rather two, nearly perfectly superimposed on the sky to masquerade as one. The discovery allowed them to use the alignment to learn otherwise-unobtainable facts about the nearer galaxy.

As part of a study of 35 galaxies, the astronomers observed one called UGC 10288, a spiral galaxy more than 100 million light-years distant that appears edge-on as seen from Earth. Their multiple VLA observations in 2011 and 2012 produced the best radio-telescope images of that galaxy ever made. The detailed images surprisingly revealed a more-distant galaxy, with strong radio emission, almost directly behind UGC 10288. In previous images, the two galaxies had been blended together.

The background galaxy is nearly 7 billion light-years from Earth.

“This changed the picture, quite literally,” said Judith Irwin, of Queen’s University in Ontario, Canada. “It changed our understanding of the characteristics of UGC 10288, but also gave us an unexpected new tool for learning more about that galaxy,” Irwin added. The alignment of a foreground galaxy with such a strongly-emitting background galaxy with extended jets probably is the first such alignment found, the astronomers said.

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IMAGE RELEASE: A Microquasar Makes A Giant Manatee Nebula

January 20, 2013 Leave a comment

Top Credits: NRAO/AUI/NSF, K. Golap, M. Goss; NASA’s Wide Field Survey Explorer (WISE) Bottom Credit: Tracy Colson

Top Credits: NRAO/AUI/NSF, K. Golap, M. Goss; NASA’s Wide Field Survey Explorer (WISE) Bottom Credit: Tracy Colson

A new view of a 20,000-year old supernova remnant demonstrates the upgraded imaging power of the National Science Foundation’s (NSF) Karl G. Jansky Very Large Array (VLA) and provides more clues to the history of this giant cloud that resembles a beloved endangered species, the Florida Manatee. W50 is one of the largest supernova remnants ever viewed by the VLA. At nearly 700 light years across, it covers two degrees on the sky – that’s the span of four full Moons!

The enormous W50 cloud formed when a giant star, 18,000 light years away in the constellation of Aquila, exploded as a supernova around twenty thousand years ago, sending its outer gases flying outward in an expanding bubble. The remaining, gravitationally-crushed relic of that giant star, most likely a black hole, feeds on gas from a very close, companion star. The cannibalized gas collects in a disk around the black hole. The disk and black hole’s network of powerful magnetic field lines acts like an enormous railroad system to snag charged particles out of the disk and channel them outward in powerful jets traveling at nearly the speed of light. This system of a black hole and its feeder star shines brightly in both radio waves and X-rays and is known collectively as the SS433 microquasar.

Full Story and Image Links: https://www.nrao.edu/pr/2013/w50/

Surprising Black-Hole Discovery Changes Picture Of Globular Star Clusters

October 4, 2012 1 comment

An unexpected discovery by astronomers using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) is forcing scientists to rethink their understanding of the environment in globular star clusters, tight-knit collections containing hundreds of thousands of stars.

The astronomers used the VLA to study a globular cluster called Messier 22 (M22), a group of stars more than 10,000 light-years from Earth. They hoped to find evidence for a rare type of black hole in the cluster’s center. They wanted to find what scientists call an intermediate-mass black hole, more massive than those a few or more times the Sun’s mass, but smaller than the supermassive black holes found at the cores of galaxies.

“We didn’t find what we were looking for, but instead found something very surprising — two smaller black holes,” said Laura Chomiuk, of Michigan State University and the National Radio Astronomy Observatory. “That’s surprising because most theorists said there should be at most one black hole in the cluster,” she added.

Full Story: http://www.nrao.edu/pr/2012/m22/

New Tools Unveiling Astronomical Mysteries

February 17, 2012 Leave a comment

Image Credit: Bill Saxton, NRAO/AUI/NSF

Image Credit: Bill Saxton, NRAO/AUI/NSF

Two new and powerful research tools are helping astronomers gain key insights needed to transform our understanding of important processes across the breadth of astrophysics. The Atacama Large Millimeter/submillimeter Array (ALMA), and the newly-expanded Karl G. Jansky Very Large Array (VLA) offer scientists vastly improved and unprecedented capabilities for frontier research.

The cutting-edge research enabled by these powerful telescope systems extends from unlocking the mysteries of star- and planet-formation processes in the Milky Way and nearby galaxies, to probing the emergence of the first stars and galaxies at the Universe’s “cosmic dawn,” and along the way helping scientists figure out where Earth’s water came from.

A trio of scientists outlined recent accomplishments of ALMA and the Jansky VLA, both of which are in the “early science” phase of their development, as construction progresses toward their completion. The astronomers spoke to the American Association for the Advancement of Science annual meeting in Vancouver, British Columbia.

One exciting area where the two facilities are expected to unlock longstanding mysteries is the study of how new stars and planets form, in our own Milky Way Galaxy and in its nearby neighbors.

Full Story: http://www.nrao.edu/pr/2012/aaasdisks/

Seeking a New Name for Transformed Scientific Icon

October 17, 2011 Leave a comment

The most famous radio telescope in the world is about to get a new name. The Very Large Array, known around the world, isn’t what it used to be. The iconic radio telescope, known around the world through movies, documentaries, music videos, newspaper and magazine articles, advertisements, textbooks, and thousands of scientific papers, is nearing the completion of an amazing transformation. More than a decade of effort has replaced the VLA’s original, 1970s-vintage electronics with modern, state-of-the-art equipment.

The result is a completely new scientific facility.

“The VLA Expansion Project, begun in 2000, has increased the VLA’s technical capabilities by factors of as much as 8,000, and the new system allows scientists to do things they never could do before,” said Fred K.Y. Lo, Director of the National Radio Astronomy Observatory. “After more than three decades on the frontiers of science, the VLA now is poised for a new era as one of the world’s premier tools for meeting the challenges of 21st-Century astrophysics,” he added.

And so it’s time, the Observatory has decided, to give this transformed scientific facility a new name to reflect its new capabilities.

The Observatory is seeking ideas for a new name from the public and the scientific community.

Full Story: http://www.nrao.edu/pr/2011/rename/