karl g. jansky very large array

VLA Reveals Distant Galaxy’s Magnetic Field

With the help of a gigantic cosmic lens, astronomers have measured the magnetic field of a galaxy nearly five billion light-years away. The achievement is giving them important new clues about a problem at the frontiers of cosmology – the nature and origin of the magnetic fields that play an important role in how galaxies develop over time.

The scientists used the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) to study a star-forming galaxy that lies directly between a more-distant quasar and Earth. The galaxy’s gravity serves as a giant lens, splitting the quasar’s image into two separate images as seen from Earth. Importantly, the radio waves coming from this quasar, nearly 8 billion light-years away, are preferentially aligned, or polarized.

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Observatories Combine to Crack Open the Crab Nebula

Astronomers have produced a highly detailed image of the Crab Nebula, by combining data from telescopes spanning nearly the entire breadth of the electromagnetic spectrum, from radio waves seen by the Karl G. Jansky Very Large Array (VLA) to the powerful X-ray glow as seen by the orbiting Chandra X-ray Observatory. And, in between that range of wavelengths, the Hubble Space Telescope’s crisp visible-light view, and the infrared perspective of the Spitzer Space Telescope.

The Crab Nebula, the result of a bright supernova explosion seen by Chinese and other astronomers in the year 1054, is 6,500 light-years from Earth. At its center is a super-dense neutron star, rotating once every 33 milliseconds, shooting out rotating lighthouse-like beams of radio waves and light – a pulsar (the bright dot at image center). The nebula’s intricate shape is caused by a complex interplay of the pulsar, a fast-moving wind of particles coming from the pulsar, and material originally ejected by the supernova explosion and by the star itself before the explosion.

This image combines data from five different telescopes: the VLA (radio) in red; Spitzer Space Telescope (infrared) in yellow; Hubble Space Telescope (visible) in green; XMM-Newton (ultraviolet) in blue; and Chandra X-ray Observatory (X-ray) in purple.

The new VLA, Hubble, and Chandra observations all were made at nearly the same time in November of 2012. A team of scientists led by Gloria Dubner of the Institute of Astronomy and Physics (IAFE), the National Council of Scientific Research (CONICET), and the University of Buenos Aires in Argentina then made a thorough analysis of the newly revealed details in a quest to gain new insights into the complex physics of the object. They are reporting their findings in the Astrophysical Journal.

“Comparing these new images, made at different wavelengths, is providing us with a wealth of new detail about the Crab Nebula. Though the Crab has been studied extensively for years, we still have much to learn about it,” Dubner said.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.

NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.

NASA’s Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

IMAGE….In the summer of the year 1054 AD, Chinese astronomers saw a new “guest star,” that appeared six times brighter than Venus. So bright in fact, it could be seen during the daytime for several months.

This “guest star” was forgotten about until 700 years later with the advent of telescopes. Astronomers saw a tentacle-like nebula in the place of the vanished star and called it the Crab Nebula. Today we know it as the expanding gaseous remnant from a star that self-detonated as a supernova, briefly shining as brightly as 400 million suns. The explosion took place 6,500 light-years away. If the blast had instead happened 50 light-years away it would have irradiated Earth, wiping out most life forms.

In the late 1960s astronomers discovered the crushed heart of the doomed star, an ultra-dense neutron star that is a dynamo of intense magnetic field and radiation energizing the nebula. Astronomers therefore need to study the Crab Nebula across a broad range of electromagnetic radiation, from X-rays to radio waves.

This image combines data from five different telescopes: the VLA (radio) in red; Spitzer Space Telescope (infrared) in yellow; Hubble Space Telescope (visible) in green; XMM-Newton (ultraviolet) in blue; and Chandra X-ray Observatory (X-ray) in purple.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington, D.C. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.

NASA’s Jet Propulsion Laboratory, Pasadena, California, manages the Spitzer Space Telescope for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena, California. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

VLA GIVES NEW INSIGHT INTO GALAXY CLUSTER’S SPECTACULAR “MINI-HALO”

Astronomers using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) have discovered new details that are helping them decipher the mystery of how giant radio-emitting structures are formed at the center of a cluster of galaxies.

The scientists studied a cluster of thousands of galaxies more than 250 million light-years from Earth, named the Perseus Cluster after the constellation in which it appears. Embedded within the center, the Perseus Cluster hosts a pool of superfast particles that emit radio waves, creating a radio structure known as a “mini-halo.” Mini-haloes have been found in about 30 galaxy clusters, but the halo in the Perseus Cluster is the largest known, about 1.3 million light-years in diameter, or 10 times the size of our Milky Way Galaxy.

The sizes of the mini-haloes have presented a puzzle to astronomers. As the particles travel away from the cluster’s center, they should slow down and stop emitting radio waves long before they reach the distances observed, according to theory.

“At large distances from the central galaxy, we don’t expect to be able to see these haloes,” said Marie-Lou Gendron-Marsolais, of the University of Montreal. “However, we do see them and we want to know why,” she added.

The astronomers took advantage of the upgraded capabilities of the VLA to make new images of the Perseus Cluster that were both more sensitive to fainter radio emissions and provided higher resolution than previous radio observations.

“The new VLA images provided an unprecedented view of the mini-halo by revealing a multitude of new structures within it,” said Julie Hlavacek-Larrondo, also of the University of Montreal. “These structures tell us that the origin of the radio emission is not as simple as we thought,” she said.

The new details indicate that the halo’s radio emission is caused by complex mechanisms that vary throughout the cluster. As theorized before, some radio emission is caused by particles being reaccelerated when small groups of galaxies collide with the cluster and give the particles a gravitational shove. In addition, however, the scientists now think that the radio emission is also caused by the powerful jets of particles generated by the supermassive black hole at the core of the central galaxy that give an extra “kick” of energy to the particles.

“This would help explain the rich variety of complex structures that we see,” Gendron-Marsolais said.

“The high-quality images that the upgraded VLA can produce will be key to helping us gain new insights into these mini-haloes in our quest to understand their origin,” Hlavacek-Larrondo said. The VLA, built during the 1970s, was equipped with all-new electronics to bring it up to the technological state of the art by a decade-long project completed in 2012.

IMAGE….VLA image of radio-emitting mini-halo in the Perseus Cluster of galaxies. Radio emission in red; optical in white.
Credit: Gendron-Marsolais et al.; NRAO/AUI/NSF; NASA; SDSS.

New radio map of Jupiter reveals what's beneath colorful clouds

Astronomers using the upgraded Karl G. Jansky Very Large Array in New Mexico have produced the most detailed radio map yet of the atmosphere of Jupiter, revealing the massive movement of ammonia gas that underlies the colorful bands, spots and whirling clouds visible to the naked eye.

The University of California, Berkeley researchers measured radio emissions from Jupiter’s atmosphere in wavelength bands where clouds are transparent. The observers were able to see as deep as 100 kilometers (60 miles) below the cloud tops, a largely unexplored region where clouds form.

The planet’s thermal radio emissions are partially absorbed by ammonia gas. Based on the amount of absorption, the researchers could determine how much ammonia is present and at what depth.

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G352.7-0.1
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. This is seen in a new composite image of G352 that contains X-rays from NASA’s Chandra X-ray Observatory in blue and radio data from the National Science Foundation’s Karl G. Jansky Very Large Array in pink. These data have also been combined with infrared data from the Spitzer Space Telescope in orange, and optical data from the Digitized Sky Survey in white.

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

Starbursting in the Galaxy M82

Messier 82 (M82), the galaxy in which the nearest supernova in decades recently exploded, also is the closest galaxy that is undergoing a rapid burst of star formation, known as a starburst. About 12 million light-years away, it is seen nearly edge-on, as shown in the larger, visible-light image from the Hubble Space Telescope. The inset is a new radio image, made with the Karl G. Jansky Very Large Array (VLA), that reveals fresh information about the central 5200 light-years of the galaxy. The radio emission seen here is produced by ionized gas and by fast-moving electrons interacting with the interstellar magnetic field. The bright dots are a mix of star-forming regions and supernova remnants, the debris from stellar explosions; analysis of the VLA data tells scientists which of these are which. Scientists also are studying the faint, wispy features, many of which were previously unseen, to investigate their relationship with this galaxy’s starburst-driven superwind. Supernova 2014J is located outside the inset, to the right. VLA observations to date show that, like all other supernovae of its particular type, SN 2014J has not yet been found to be emitting radio waves.

Credit: Josh Marvil (NM Tech/NRAO), Bill Saxton (NRAO/AUI/NSF), NASA

Young Heavyweight Star Identified in the Milky Way

Astronomers have identified a young star, located almost 11,000 light-years away, which could help us understand how the most massive stars in the universe are formed. This young star, already more than 30 times the mass of our Sun, is still in the process of gathering material from its parent molecular cloud, and may be even more massive when it finally reaches adulthood.

The researchers, led by a team at the University of Cambridge, have identified a key stage in the birth of a very massive star, and found that these stars form in a similar way to much smaller stars like our Sun - from a rotating disc of gas and dust. The results will be presented this week at the Star Formation 2016 conference held at the University of Exeter, and are reported in the Monthly Notices of the Royal Astronomical Society.

In our galaxy, massive young stars - those with a mass at least eight times greater than the Sun - are much more difficult to study than smaller stars. This is because they live fast and die young, making them rare among the 100 billion stars in the Milky Way, and on average, they are much further away.

“An average star like our Sun is formed over a few million years, whereas massive stars are formed orders of magnitude faster - around 100,000 years,” said Dr. John Ilee from Cambridge’s Institute of Astronomy, the study’s lead author. “These massive stars also burn through their fuel much more quickly, so they have shorter overall lifespans, making them harder to catch when they are infants.”

The protostar that Ilee and his colleagues identified resides in an infrared dark cloud - a very cold and dense region of space which makes for an ideal stellar nursery. However, this rich star-forming region is difficult to observe using conventional telescopes, since the young stars are surrounded by a thick, opaque cloud of gas and dust.

But by using the Submillimeter Array (SMA) in Hawaii and the Karl G Jansky Very Large Array (VLA) in New Mexico, both of which use relatively long wavelengths of light to observe the sky, the researchers were able to ‘see’ through the cloud and into the stellar nursery itself.

By measuring the amount of radiation emitted by cold dust near the star, and by using unique fingerprints of various different molecules in the gas, the researchers were able to determine the presence of a 'Keplerian’ disc - one which rotates more quickly at its center than at its edge.

“This type of rotation is also seen in the solar system - the inner planets rotate around the Sun more quickly than the outer planets,” said Ilee. “It’s exciting to find such a disc around a massive young star, because it suggests that massive stars form in a similar way to lower mass stars, like our Sun.”

The initial phases of this work were part of an undergraduate summer research project at the University of St. Andrews, funded by the Royal Astronomical Society (RAS). The undergraduate carrying out the work, Pooneh Nazari, said, “My project involved an initial exploration of the observations, and writing a piece of software to 'weigh’ the central star. I’m very grateful to the RAS for providing me with funding for the summer project - I’d encourage anyone interested in academic research to try one!”

From these observations, the team measured the mass of the protostar to be over 30 times the mass of the Sun. In addition, the disc surrounding the young star was also calculated to be relatively massive, between two and three times the mass of our Sun. Dr. Duncan Forgan, also from St. Andrews and lead author of a companion paper, said, “Our theoretical calculations suggest that the disc could in fact be hiding even more mass under layers of gas and dust. The disc may even be so massive that it can break up under its own gravity, forming a series of less massive companion protostars.”

The next step for the researchers will be to observe the region with the Atacama Large Millimeter Array (ALMA), located in Chile. This powerful instrument will allow any potential companions to be seen, and allow researchers to learn more about this intriguing young heavyweight in our galaxy.

Two Galaxies Masquerading as One

What might look like a colossal jet shooting away from a galaxy turns out to be an illusion. New data from the National Science Foundation’s Karl G. Jansky Very Large Array (VLA), combined with an infrared view from NASA’s Spitzer Space Telescope, reveals two galaxies, one lying behind the other, that had been masquerading as one.

In a new image highlighting the chance alignment, radio data from the VLA are magenta and infrared observations from Spitzer are blue.

The closer galaxy, called UGC 10288, is located 100 million light-years away. It is spiral in shape, but from our viewpoint on Earth, we are seeing its thin edge. Infrared observations of such edge-on galaxies penetrate the thick clouds of dust that wrap through the spiral arms and block visible light views. The bright glow of dense starfields that run along the galaxy’s central plane, and in its core, are easily seen.

The farther galaxy, seen in magenta, is nearly 7 billion light-years away. Two giant jets shoot away from this galaxy, one of which is seen above the plane of the closer galaxy’s disk, while the other is hidden behind it. A second distant radio galaxy can be seen as a magenta dot further to the right.

Earlier images of the two galaxies appeared as one fuzzy blob, and fooled astronomers into thinking they were looking at one galaxy. Thanks to the VLA pulling the curtain back, revealing the chance alignment, the scientists have a unique opportunity to learn otherwise-unobtainable facts about the nearer galaxy.

This image was taken after Spitzer’s liquid coolant ran dry in May 2009, marking the beginning of its “warm” mission. Light from the telescope’s remaining infrared channels are colored blue at 3.6 microns and green at 4.5 microns. 7.3 cm radio light from the VLA is magenta.

Image Credit: NASA/JPL-Caltech/NRAO