Iconic Telescope Array Gets a New Name

VLA at twilight. Image by Dave Finley, courtesy of NRAO/AUI

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The pop culture-rich Very Large Array has been updated with state-of-the-art technology and to befit the VLA’s new capabilities, the National Radio Astronomy Observatory (NRAO) has given it a new name. Recall, back in October 2011, the NRAO asked for the public’s help in choosing a new name, and 17,023 people from 65 different countries responded by sending 23,331 suggestions.

The new name for the world’s most famous radio telescope is the “Karl G. Jansky Very Large Array” to honor the founder of radio astronomy. Radio astronomy enables the study of the Universe via radio waves naturally emitted by objects in space.

The VLA has been part of movie plots, is on album covers, in comic books and video games. It has now been transformed from its original 1970s-vintage technology with the latest equipment, and the NRAO says that the upgrades will greatly increase the VLA’s technical capabilities and scientific impact.

The new name was announced at the American Astronomical Society’s meeting in Austin, Texas. The new name will become official at a re-dedication ceremony at the VLA site in New Mexico on March 31, 2012.

Karl G. Jansky. Credit: NRAO/AUI/NSF

Karl Guthe Jansky (1905-1950) joined Bell Telephone Laboratories in 1928, and was assigned the task of studying radio waves that interfered with the recently-opened transatlantic radiotelephone service.

He designed and built advanced, specialized equipment, and made observations over the entire year of 1932 that allowed him to identify thunderstorms as major sources of radio interference, along with a much weaker, unidentified radio source. Careful study of this “strange hiss-type static” led to the conclusion that the radio waves originated from beyond our Solar System, and indeed came from the center of our Milky Way Galaxy.

His discovery was reported on the front page of the New York Times on May 5, 1933, and published in professional journals. Janksy thus opened an entirely new “window” on the Universe. Astronomers previously had been confined to observing those wavelengths of light that our eyes can see.

NRAO officials say the new name recognizes the VLA’s dramatic new capabilities and its promise for important scientific discoveries in the future.

“When Karl Jansky discovered radio waves coming from the center of the Milky Way Galaxy in 1932, he blazed a scientific trail that fundamentally changed our perception of the Universe. Now, the upgraded VLA will continue that tradition by equipping scientists to address outstanding questions confronting 21st-Century astronomy,” said NRAO Director Fred K.Y. Lo.

“It is particularly appropriate that the upgraded Very Large Array honor the memory and accomplishments of Karl Jansky,” Lo explained, adding that “the new Jansky VLA is by far the most sensitive such radio telescope in the world, as was the receiver and antenna combination that Jansky himself painstakingly developed 80 years ago.”

Lo said they deeply appreciate all the suggestions for a new name, as well as the strong public interest in the VLA and in astronomy. “There was a tremendous amount of thought and creativity that went into the numerous submissions,” he said. “In the end, we decided it was most appropriate to name the telescope after a genuine pioneer who took the first step on the road that led to this powerful scientific facility,” he said.

The Jansky VLA is more than ten times more sensitive to faint radio emission than the original VLA, and covers more than three times more radio frequency range. It will provide astronomers the capability to address key outstanding scientific questions, ranging from the formation of stars and planets in the Milky Way and nearby galaxies, to mapping magnetic fields in galaxies and clusters, and imaging the gas that forms the earliest galaxies.

Nebula of Many Names Revealed in Beautiful New Image

This image of the Omega Nebula (Messier 17), captured by ESO's Very Large Telescope (VLT), is one of the sharpest of this object ever taken from the ground. It shows the dusty, rosy central parts of the famous star-forming region in fine detail. Credit: ESO

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The Omega Nebula goes by many names, depending on who observed it when and what they thought they saw. So, what do you see in this new image from the Very Large Telescope? This is one of the sharpest images of this nebula ever taken from the ground, and it reveals incredible detail in the smoky-pink gas clouds and dark dust, highlighted with brilliant newborn stars.

Astronomers from the European Southern Observatory said the “seeing” — a term astronomers use to measure the distorting effects of Earth’s atmosphere — on the night of the observations this image was taken was very good, thus this incredibly vivid image.

A common measure for seeing is the apparent diameter of a star when seen through a telescope. In this case, the measure of seeing was an extremely favorable 0.45 arcseconds, meaning little blurring and twinkling occurred while the VLT stared at this nebula.

The other names given to the Omega Nebula include the Swan Nebula, the Horseshoe Nebula and the Lobster Nebula. It also has the official catalog names of Messier 17 (M17) and NGC 6618. The nebula is located about 6,500 light-years away in the constellation of Sagittarius. It is a popular target of astronomers, and is one of the youngest and most active stellar nurseries for massive stars in the Milky Way.

The gas and dust visible in the Omega Nebula provides the raw materials for creating the next generation of stars. The newborn stars shine brightly in blue-white light, illuminating the entire nebula. , The gas appears in pink hues, as the hydrogen gas glows from the intense ultraviolet rays from the hot young stars.

The image was taken with the FORS (FOcal Reducer and Spectrograph) instrument on Antu, one of the four Unit Telescopes of the VLT.

Source: ESO

Early Galaxy Chemistry: VLT Observes Gamma-Ray Burst

Artist’s impression of a gamma-ray burst shining through two young galaxies in the early Universe. Credit: ESO

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“Shot through the heart and you’re to blame…” There’s nothing more powerful than a gamma-ray burst. These abrupt, mega-bright events are captured by orbiting telescopes where the information is immediately relayed to the ground for observation in visible light and infra-red. Some events are so powerful that they linger for hours or even days. But just how quick can we spot them? A burst cataloged as GRB 090323 was picked up by the NASA Fermi Gamma-ray Space Telescope, then confirmed by the X-ray detector on NASA’s Swift satellite and with the GROND system at the MPG/ESO 2.2-metre telescope in Chile. Within a day it was being studied by ESO’s Very Large Telescope. It was so intense it penetrated its host galaxy and another… heading out on a 12 billion light year journey just to get here.

“When we studied the light from this gamma-ray burst we didn’t know what we might find. It was a surprise that the cool gas in these two galaxies in the early Universe proved to have such an unexpected chemical make-up,” explains Sandra Savaglio (Max-Planck Institute for Extraterrestrial Physics, Garching, Germany), lead author of the paper describing the new results. “These galaxies have more heavy elements than have ever been seen in a galaxy so early in the evolution of the Universe. We didn’t expect the Universe to be so mature, so chemically evolved, so early on.”

As the brilliant beacon passed through the galaxies, the gases performed as a filter, absorbing some wavelengths of light. But the real kicker here is we wouldn’t have even known these galaxies existed if it weren’t for the gamma-ray burst! Because the light was affected, astronomers were able to detect the “composition of the cool gas in these very distant galaxies, and in particular how rich they were in heavy elements.” It had been surmised that early galaxies would have less heavy elements since their stellar populations weren’t old enough to have produced them… But the findings pointed otherwise. These new galaxies were rich in heavy elements and going against what we thought we knew about galactic evolution.

So exactly what does that mean? It would appear these new, young galaxies are forming stars at an incredible rate. To enrich their gases so quickly, it’s possible they are in a merger process. While this isn’t a new concept, it just may support the theory that gamma-ray bursts can be associated with “vigorous massive star formation”. Furthermore, it’s surmised that rapid stellar growth may have simply stopped in the primordial Universe. What’s left that we can observe some 12 billion years later are mere shadows of what once was… like cool dwarf stars and black holes. These two newly discovered galaxies are like finding a hidden stain on the outskirts of the distant Cosmos.

“We were very lucky to observe GRB 090323 when it was still sufficiently bright, so that it was possible to obtain spectacularly detailed observations with the VLT. Gamma-ray bursts only stay bright for a very short time and getting good quality data is very hard. We hope to observe these galaxies again in the future when we have much more sensitive instruments, they would make perfect targets for the E-ELT,” concludes Savaglio.

Original Story Source: ESO Press Release. For Further Reading: Super-solar Metal Abundances in Two Galaxies at z ~ 3.57 revealed by the GRB 090323 Afterglow Spectrum.

Sunny Side Up: New Image of the Fried Egg Nebula Reveals a Rare Yellow Hypergiant Star

An image from the Very Large Telescope of IRAS 17163-3907, which has a huge dusty double shell surrounding the central hypergiant star. The star and its shells resemble an egg white around a yolky centre, leading astronomers to nickname the object the Fried Egg Nebula. Credit: ESO/E. Lagadec

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A new look at the Fried Egg Nebula has revealed one of the rarest classes of stars in the Universe, a yellow hypergiant. This “sunny-side-up” view shows for the first time a huge dusty double shell surrounding this huge star.

“This object was known to glow brightly in the infrared but, surprisingly, nobody had identified it as a yellow hypergiant before,” said Eric Lagadec from the European Southern Observatory, who led the team that produced the new images.

And there’s good reason to keep an eye on this star: it will likely soon die an explosive death, and will be one of the next supernova explosions in our galaxy.

The monster star, IRAS 17163-3907 has a diameter about a thousand times bigger than our Sun. At a distance of about 13,000 light-years from Earth, it is the closest yellow hypergiant found to date and new observations show it shines some 500,000 times more brightly than the Sun. The total mass of this star is estimated to be roughly twenty times that of the Sun.

The star and its shells resemble an egg white around a yolky center, hence, the nickname of the Fried Egg Nebula – which is much easier to say than IRAS 17163-3907.

The observations of the star and the discovery of its surrounding shells were made using the VISIR infrared camera on the VLT. The pictures are the first of this object to clearly show the material around it and reveal two almost perfectly spherical shells.

Astronomers say that if the Fried Egg Nebula were placed in the center of the Solar System, Earth would lie deep within the star itself and the planet Jupiter would be orbiting just above its surface. The much larger surrounding nebula would engulf all the planets and dwarf planets and even some of the comets that orbit far beyond the orbit of Neptune. The outer shell has a radius of 10,000 times the distance from the Earth to the Sun.

Yellow hypergiants are in an extremely active phase of their evolution, undergoing a series of explosive events — this star has ejected four times the mass of the Sun in just a few hundred years. The material flung out during these bursts has formed the extensive double shell of the nebula, which is made of dust rich in silicates and mixed with gas.

Source: ESO

The Lyman-Alpha Blob That Ate The Universe…

Observations from ESO’s Very Large Telescope have shed light on the power source of a rare vast cloud of glowing gas in the early Universe. The observations show for the first time that this giant “Lyman-alpha blob” — one of the largest single objects known — must be powered by galaxies embedded within it. The results appear in the 18 August issue of the journal Nature. Credit: ESO

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It’s called a Lyman-alpha blob and it’s one of the largest known single objects in the Universe. It first made its presence known in the year 2000 and we know it’s located some 11.5 billion light years away. What will really get your attention is the size. LAB-1 has a diameter of about 300,000 light-years across!

Utilizing ESO’s Very Large Telescope (VLT), a team of astronomers were checking out areas of the early Universe where matter was the most dense – home to huge and very luminous rare structures called Lyman-alpha blobs. While there wasn’t anything in particular they were looking for, what they captured was something unique… evidence of polarization.

“We have shown for the first time that the glow of this enigmatic object is scattered light from brilliant galaxies hidden within, rather than the gas throughout the cloud itself shining.” explains Matthew Hayes (University of Toulouse, France), lead author of the paper.

These super-sized clouds of hydrogen gas stagger the imagination with their sheer dimensions. Some reach diameters of a few hundred thousand light-years – large enough to enfold the Milky Way three times over – and are as luminous as the most powerful galaxy we can observe. Since Lyman-alpha blobs are located so far away, we can only see them as they were when the Universe was a few billion years old, but they have a lot to teach us about their origins. Some theories suggest they shine when cool gas is pulled in by the blob’s powerful gravity and heated. Other conjectures are they are illuminated from within – lit by extreme star-forming events, supernovae or hungry black holes swallowing matter.

Thanks to these recent studies, the latest idea is the illumination comes from embedded galaxies. How do astronomers know this? By measuring whether the light from the blob was polarized. By measuring the physical processes that produced the light with sensitive equipment, researchers can gain insight from scattering or reflecting properties. However, the task hasn’t been easy considering the great distance of Lyman-alpha blobs.

“These observations couldn’t have been done without the VLT and its FORS instrument. We clearly needed two things: a telescope with at least an eight-metre mirror to collect enough light, and a camera capable of measuring the polarisation of light. Not many observatories in the world offer this combination.” adds Claudia Scarlata (University of Minnesota, USA), co-author of the paper.

According to ESO, the team observed their target for about 15 hours with the Very Large Telescope, and the light from the Lyman-alpha blob LAB-1 showed a centralized ring of polarization – but no central polarized spot. “This effect is almost impossible to produce if light simply comes from the gas falling into the blob under gravity, but it is just what is expected if the light originally comes from galaxies embedded in the central region, before being scattered by the gas. The astronomers now plan to look at more of these objects to see if the results obtained for LAB-1 are true of other blobs.”

Before they find us…

Original Story Source: ESO Science News Release.