Posted on by Tammy Plotner

Fast Working ALMA Resolves Star-Forming Galaxies

A team of astronomers has used ALMA (the Atacama Large Millimeter/submillimeter Array) to pinpoint the locations of over 100 of the most fertile star-forming galaxies in the early Universe. Credit:: ALMA (ESO/NAOJ/NRAO), J. Hodge et al., A. Weiss et al., NASA Spitzer Science Center

In a scenario where millions of years are considered a short period of time, hours are barely a blink of an eye. While it might take ten years or more to observe a group of galaxies with a modicum of detail for telescopes around the world, the Atcama Large Millimeter/submillimeter Array (ALMA) telescope was able to do the job at amazing speed. In just a matter of hours, a team of astronomers using this super-powerful telescope homed in on the location of over a hundred star-forming galaxies in the early Universe.

Once upon a time, huge amounts of star birth occurred in early galaxies which were rich in cosmic dust. Studying these galaxies is imperative to our understanding of galactic formation and evolution – but it has proved difficult in visible light because the very dust which supports star formation also cloaks the galaxies in which they are formed. However, thanks to telescopes like ALMA, we’re able to identify and observe these galaxies by focusing on longer wavelengths. Light that comes in around one millimetre is the perfect playground for such study.

“Astronomers have waited for data like this for over a decade. ALMA is so powerful that it has revolutionised the way that we can observe these galaxies, even though the telescope was not fully completed at the time of the observations,” said Jacqueline Hodge (Max-Planck-Institut für Astronomie, Germany), lead author of the paper presenting the ALMA observations.

Just how do we know where these galaxies are located? Through the use of the ESO-operated Atacama Pathfinder Experiment telescope (APEX), astronomers were able to map these dust obscured targets to a certain degree. APEX focused its capabilities on an area of sky about the size of the full Moon in the constellation of Fornax. The study – Chandra Deep Field South – has been taken on by a variety of telescopes located both here on Earth and in space. Here is where APEX has been credited with locating 126 dusty galaxies. However, these images aren’t all they could be. Star forming areas appeared as blobs and sometimes could over-ride better images made at other wavelengths. Through the use of ALMA, these observations have been augmented, furthering the resolution in the millimetre/submillimetre portion of the spectrum and assisting astronomers in knowing precisely which galaxies are forming stars.

Loading player…

This video sequence starts with a broad view of the sky, including the famous constellation of Orion (The Hunter). We gradually close in on an unremarkable patch of sky called the Chandra Deep Field South that has been studied by many telescopes on the ground and in space. Credit: ALMA (ESO/NAOJ/NRAO), APEX (MPIfR/ESO/OSO), J. Hodge et al., A. Weiss et al., NASA Spitzer Science Center, Digitized Sky Survey 2, and A. Fujii. Music: Movetwo

As all backyard astronomers know, the larger the aperture – the better the resolution. To improve their observations of the early Universe, astronomers needed a bigger telescope. APEX consists of a twelve meter diameter dish-shaped antenna, but ALMA consists of many dishes spread over long distances. The signals from all of its parts are then combined and the result is the same as if it were a giant telescope which measured the same size as the entire array. A super dish!

With the assistance of ALMA, the astronomers then took on the galaxies from the APEX map. Even though the ALMA array is still under construction and using less than a quarter of its capabilities, the team was able to complete this beginning phase of scientific observations. Speedy ALMA was up to the task. At only two minutes per galaxy, this “Super Scope” was able to resolve each one within a minuscule area two hundred times smaller than the original APEX blobs… and with 300% more sensitivity! With a track record like that, ALMA was able to double the number of observations in a matter of hours. Now the researchers were able to clearly see which galaxies contained active star forming regions and distinguish cases where multiple star-forming galaxies had melded to appear as one in earlier studies.

“We previously thought the brightest of these galaxies were forming stars a thousand times more vigorously than our own galaxy, the Milky Way, putting them at risk of blowing themselves apart. The ALMA images revealed multiple, smaller galaxies forming stars at somewhat more reasonable rates,” said Alexander Karim (Durham University, United Kingdom), a member of the team and lead author of a companion paper on this work.

Apparently ALMA is going to be a huge success. These new observations have helped to confidently document dusty star-forming galaxies from the early Universe and help to create a more detailed catalog than ever before. These new findings will assist future astronomical observations by giving researchers a reliable base on these galaxies’ properties at different wavelengths. No longer will astronomers have to “guess” at which galaxies may have melded together in images… ALMA has made it clear. However, don’t rule out the use of other venues such as APEX. The combination of both play a powerful part in observing the early Universe.

“APEX can cover a wide area of the sky faster than ALMA, and so it’s ideal for discovering these galaxies. Once we know where to look, we can use ALMA to locate them exactly,” concluded Ian Smail (Durham University, United Kingdom), co-author of the new paper.

Original Story Source: ESO Science News Release.

Posted on by Nancy Atkinson

First-Ever High Resolution Radio Images of Supernova 1987A

An overlay of radio emission (contours) and a Hubble space telescope image of Supernova 1987A. Credit: ICRAR (radio contours) and Hubble (image.)

On February 23, 1987, the brightest extragalactic supernova in history was seen from Earth. Now 26 years later, astronomers have taken the highest resolution radio images ever of the expanding supernova remnant at extremely precise millimeter wavelengths. Using the Australia Telescope Compact Array radio telescope in New South Wales, Australia, Supernova 1987A has been now observed in unprecedented detail. The new data provide some unique imagery that takes a look at the different regions of the supernova remnant.

“Not only have we been able to analyze the morphology of Supernova 1987A through our high resolution imaging, we have compared it to X-ray and optical data in order to model its likely history,” said Bryan Gaensler, Director of CAASTRO (Centre for All-sky Astrophysics) at the University of Sydney.

Radio image at 7 mm. Credit: ICRAR Radio image of the remnant of SN 1987A produced from observations performed with the Australia Telescope Compact Array (ATCA).
Radio image at 7 mm. Credit: ICRAR
Radio image of the remnant of SN 1987A produced from observations performed with the Australia Telescope Compact Array (ATCA).

SN 1987A has been on one of the most-studied astronomical objects, as its “close” proximity in the Large Magellanic Cloud allows it to be a focus for researchers around the world. Astronomers says it has provided a wealth of information about one of the Universe’s most extreme events.

“Imaging distant astronomical objects like this at wavelengths less than 1 centimetre demands the most stable atmospheric conditions,” said lead author, Giovanna Zanardo of ICRAR, the International Center for Radio Astronomy Research. “For this telescope these are usually only possible during cooler winter conditions but even then, the humidity and low elevation of the site makes things very challenging,”

Unlike optical telescopes, a radio telescope can operate in the daytime and can peer through gas and dust allowing astronomers to see the inner workings of objects like supernova remnants, radio galaxies and black holes.

“Supernova remnants are like natural particle accelerators, the radio emission we observe comes from electrons spiraling along the magnetic field lines and emitting photons every time they turn. The higher the resolution of the images the more we can learn about the structure of this object,” said Professor Lister Staveley-Smith, Deputy Director of ICRAR and CAASTRO.

An RGB overlay of the supernova remnant. Credit: ICRAR A Red/Green/Blue overlay of optical, X-Ray and radio observations made by 3 different telescopes. In red are the 7-mm (44GHz) observations made with the Australian Compact Array in New South Wales, in green are the optical observations made by the Hubble Space Telescope, and in blue is an X-ray view of the remnant, observed by Nasa's space based Chandra X-ray Observatory.
An RGB overlay of the supernova remnant. Credit: ICRAR
A Red/Green/Blue overlay of optical, X-Ray and radio observations made by 3 different telescopes. In red are the 7-mm (44GHz) observations made with the Australian Compact Array in New South Wales, in green are the optical observations made by the Hubble Space Telescope, and in blue is an X-ray view of the remnant, observed by Nasa’s space based Chandra X-ray Observatory.

Scientists study the evolution of supernovae into supernova remnants to gain an insight into the dynamics of these massive explosions and the interaction of the blast wave with the surrounding medium.

The team suspects a compact source or pulsar wind nebula to be sitting in the centre of the radio emission, implying that the supernova explosion did not make the star collapse into a black hole. They will now attempt to observe further into the core and see what’s there.

Their paper was published in the Astrophysical Journal.

Source: ICRAR

Posted on by Jason Major

A Radio Astronomer’s Paradise

Just a few of ALMA's 66 giant radio telescopes (NRAO)

Last month a dozen journalists from around North America were guests of the National Radio Astronomy Observatory and got to take a trip to the Atacama Desert in Chile to attend the inauguration of the Atacama Large Millimeter/submillimeter Array observatory — ALMA, for short.

It was, in no uncertain terms, a radio astronomer’s paradise.

Join one radio astronomer, Dr. Nicole Gugliucci, on her trip to the 5100-meter-high Chajnantor Plateau to visit the ALMA sites in this video, also featuring NRAO’s Tania Burchell, John Stoke, Charles Blue and the Planetary Society’s Mat Kaplan.

Read about this and more on Nicole’s NoisyAstronomer blog.

ALMA will open a new window on celestial origins, capturing never-before seen details about the very first stars and galaxies in the Universe, probing the heart of our galaxy, and directly imaging the formation of planets. It is the largest leap in telescope technology since Galileo first aimed a lens on the Universe.

Posted on by Tammy Plotner

LOFAR Captures Giant Galaxy

Overlay of the new GRG (blue-white colors) on an optical image from the Digitized Sky survey. The inset shows the central galaxy triplet (image from Sloan Digital Sky Survey). The image is about 2 Mpc across.

Our Universe is full of surprises. Sometimes those surprises come in packages so overwhelmingly huge that it’s almost impossible for us to comprehend the size. Thus is the case of a newly discovered “giant galaxy”. It’s a galaxy which extends millions of light years across intergalactic space, covering an area as much as a half degree of sky. It’s a new class of monster – one called a Giant Radio Galaxy.

Thanks to the work of an international team of astronomers made up of about fifty members from various institutes and led by ASTRON astronomer, Dr. George Heald, there’s a new discovery which can be credited to the powerful International LOFAR Telescope (ILT). During a perpetual all-sky radio survey – the Multi-frequency Snapshot Sky Survey (MSSS) – the team captured some images which revealed a new radio source. This wasn’t just a weak signal that showed a new blotch. It was a source the size of the full Moon projected on the sky! The huge new radio emission appears to have originated up to hundreds of million of years ago from a single member of a interacting triple galaxy system and spread itself across a vast expanse of space.

Cataloged as UGC 09555, the parent galaxy system is located some 750 million light years from our solar system. Its central galaxy had been studied before and was known to have a flat radio spectrum – a signature of giant radio galaxies. Astronomers speculate when the trio interacted, material was released – spreading out over millions of light years and releasing very low radio frequencies. It’s a source that’s either very powerful, or it’s very old.

Enter LOFAR and the MSSS Survey…

As part of a well orchestrated attempt to image the expanse of the northern night sky at frequencies between 30 and 150 MHz, the radio researchers have taken a initial “shallow scan” image set. This new survey will allow astronomers to fashion an all-sky model which will eventually assist with much deeper observations. Thanks to LOFAR’s extreme sensitivity, ability to operate at low frequencies and suitability to observe old sources, the survey was able to reveal this gargantuan galaxy. Picture its size again in your mind. This Giant Radio Galaxy covers as much sky as the Moon, yet it’s 750 million light years away! As the MSSS Survey continues to scan the skies, who knows what may yet be discovered?

With capabilities as sensitive as some of the world’s greatest radio telescopes, such as the Very Large Array (VLA) in the USA, ASTRON’s Westerbork Synthesis Radio Telescope (WSRT), and the Giant Metrewave Radio Telescope (GMRT) in India, LOFAR will take discoveries such as Giant Radio Galaxies to the next level. It will reveal objects missed by previous surveys and the broad bandwidth coverage may show us even more cosmic wonders.

Really big ones…

Original News Source: Netherlands Institute for Radio Astronomy News Release.

Posted on by Bob King

Close Passing Asteroid 2013 ET Gets Its Picture Taken

These radar images of asteroid 2013 ET were obtained when the asteroid was about 693,000 miles from Earth. The images span 1.3 hours or about 1/3 or the asteroid's rotation rate. Click to enlarge. Credit: NASA/JPL-Caltech/GSSR

Another space rock sat pretty for NASA’s big dish photographer. The 70-meter (230-feet) Goldstone antenna zinged radio waves at 2013 ET on March 10 when the asteroid flew by Earth at 2.9 lunar distances or about 693,000 miles (1.1 million km).

By studying the returned echoes, astronomers pieced together 18 images of a rugged, irregular-shaped object about 130 feet (40 m) across. Radar measurements of an asteroid’s distance and speed nail down its orbit with great accuracy, enabling scientists to predict whether or not  it might become a danger to the planet at a future date.

The Goldstone dish dish, based in the Mojave Desert near Barstow, Cal. is used for radar mapping of planets, comets, asteroids and the moon. Credit: NASA
The Goldstone dish dish, based in the Mojave Desert near Barstow, Cal. is used for radar mapping of planets, comets, asteroids and the moon. Credit: NASA

It’s also the only way outside of a sending a spacecraft to the object of seeing a small asteroid’s shape and surface features. Most optical telescopes cannot resolve asteroids as anything more than points of light.

By convention, radar images appear “lit” from above. That’s the side closest to the antenna. As you examine a radar image from top to bottom, distance from the antenna increases and the asteroid fades. If the equator of the asteroid faces the antenna, it will appear brightly illuminated at the top of the image. If the antenna faces one of the poles, the pole will be on top and lit up. It takes a bit of getting used to.

Nine radar images of near-Earth asteroid 2007 PA8 obtained between by NASA's 230-foot-wide (70-meter) Deep Space Network antenna. The part of the asteroid closest to the antenna is at top. Credit: NASA/JPL-Caltech
Nine radar images of near-Earth asteroid 2007 PA8 obtained between by NASA’s 230-foot-wide (70-meter) Deep Space Network antenna. The part of the asteroid closest to the antenna is at top. Credit: NASA/JPL-Caltech

The asteroid’s width in the images depends on the asteroid’s rotation rate and the antenna’s perspective. If the antenna stares directly down over the equator and the asteroid rotates rapidly, the images will be stretched from Doppler-shifting of the returned radar echo.

Radio waves are a form of light just like the familiar colors of the rainbow. If radio light is moving toward you, its waves bunch together more tightly and appear slightly bluer than if they were at rest. Astronomers call this a Doppler shift or blueshift.  If they’re moving away, the light waves get stretched and become “redshifted”.

Three views of asteroid 4179 Toutatis made in early Dec. 2012 by Goldstone. In all three, distance from the antenna increases from top to bottom and Doppler frequency increases toward the right, indicating Toutatis rotates from right to left, since that's the side of the asteroid approaching the observer. Credit: NASA/JPL-Caltech
Three views of asteroid 4179 Toutatis made in early Dec. 2012 by Goldstone. In all three, distance from the antenna increases from top to bottom and Doppler frequency increases toward the right, indicating Toutatis rotates from right to left, since that’s the side of the asteroid approaching the observer. Credit: NASA/JPL-Caltech

A slow-rotating asteroid will appear narrower to radar eyes, and if it doesn’t rotate at all, will show up as a “spike” of light. When the antenna happens to be point directly at a pole, the asteroid will appear to be rotating neither toward nor away from the observer and also look like a spike.

Most asteroids fall somewhere in between, and their radar portraits are close to their true shapes. Radar images show us surface textures, shape, size, rotation rate and surface features like craters. 2013 ET joins the ranks of numerous asteroids probed by radio waves from Earth as we try to grasp the complexity of our planetary neighborhood while hoping for we don’t stare down cosmic disaster anytime soon.

Posted on by Nancy Atkinson

ALMA: The View from a Different World

This image shows an aerial view of the Chajnantor Plateau, located at an altitude of 5000 meters in the Chilean Andes, where the array of ALMA antennas is located. Credit: Clem & Adri Bacri-Normier (wingsforscience.com)/ESO.

A new film called The View From Mars takes a look ALMA (Atacama Large Millimeter Array), the huge international telescope project that was inaugurated in Chile this week. It is located in the Atacama Desert, the driest place on Earth and an area that bears a striking resemblance to the Red Planet.

But the conditions there, with clear, dry skies, are perfect for astronomy. ALMA’s moveable group of 66 giant antennas do not detect visible light like conventional optical telescopes. Instead they work together to gather emissions from gas, dust and stars and make observations in millimeter wavelengths, using radio frequencies instead of visible light—with no need for darkness, so the stars can be studied around the clock. With these tools, astronomers will soon be able to look billions of years into the past, gazing at the formation of distant stars and galaxies.

“In doing so,” says filmmaker Jonathan de Villiers, “they’ll build a clearer picture of how our sun and our galaxy formed.”

Here is part one; you can see part 2 at this link.

The View From Mars: Part One on Nowness.com.

Posted on by Tammy Plotner

ALMA Eyes Most Distant Star-forming Galaxy

This schematic image represents how light from a distant galaxy is distorted by the gravitational effects of a nearer foreground galaxy, which acts like a lens and makes the distant source appear distorted, but brighter, forming characteristic rings of light, known as Einstein rings. An analysis of the distortion has revealed that some of the distant star-forming galaxies are as bright as 40 trillion Suns, and have been magnified by the gravitational lens by up to 22 times. Credit: ALMA (ESO/NRAO/NAOJ), L. Calçada (ESO), Y. Hezaveh et al.

Let’s turn down the lights and set the stage… We’re moving off through space, looking not only at distant galaxies, but the incredibly distant past. Once upon a time astronomers assumed that star formation began in massive, bright galaxies as a concentrated surge. Now, new observations taken with the Atacama Large Millimeter/submillimeter Array (ALMA) are showing us that these deluges of stellar creation may have begun much earlier than they thought.

According to the latest research published in today’s edition of the journal, Nature, and in the Astrophysical Journal, researchers have revealed fascinating discoveries taken with the new international ALMA observatory – which celebrates its inauguration today. Among its many achievements, ALMA has given us a look even deeper into space – showing us ancient galaxies which may be billions of light years distant. The observations of these starburst galaxies show us that stars were created in a frenzy out of huge deposits of cosmic gas and dust.

Loading player…

“The more distant the galaxy, the further back in time one is looking, so by measuring their distances we can piece together a timeline of how vigorously the Universe was making new stars at different stages of its 13.7 billion year history,” said Joaquin Vieira (California Institute of Technology, USA), who led the team and is lead author of the paper in the journal Nature.

Just how did these observations come about? Before ALMA, an international team of researchers employed the US National Science Foundation’s 10-metre South Pole Telescope (SPT ) to locate these distant denizens and then homed in on them to take a closer look at the “stellar baby boom” during the Universe’s beginning epoch. What they found surprised them. Apparently star forming galaxies are even more distant than previously suspected… their onslaught of stellar creation beginning some 12 billion years ago. This time frame places the Universe at just under 2 billion years old and the star formation explosion occurring some billion years sooner than astronomers assumed. The ALMA observations included two galaxies – the “most distant of their kind ever seen” – that contained an additional revelation. Not only did their distance break astronomical records, but water molecules have been detected within them.

However, two galaxies aren’t the only score for ALMA. The research team took on 26 galaxies at wavelengths of around three millimetres. The extreme sensitivity of this cutting edge technology utilizes the measurement of light wavelengths – wavelengths produced by the galaxy’s gas molecules and stretched by the expansion of the Universe. By carefully measuring the “stretch”, astronomers are able to gauge the amount of time the light has taken to reach us and refine its point in time.

“ALMA’s sensitivity and wide wavelength range mean we could make our measurements in just a few minutes per galaxy – about one hundred times faster than before,” said Axel Weiss (Max-Planck-Institut für Radioastronomie in Bonn, Germany), who led the work to measure the distances to the galaxies. “Previously, a measurement like this would have been a laborious process of combining data from both visible-light and radio telescopes.”

For the most part, ALMA’s observations would be sufficient to determine the distance, but the team also included ALMA’s data with the Atacama Pathfinder Experiment (APEX) and ESO’s Very Large Telescope for a select few galaxies. At the present time, astronomers are only employing a small segment of ALMA’s capabilities – just 16 of the 66 massive antennae – and focusing on brighter galaxies. When ALMA is fully functional, it will be able to zero in on even fainter targets. However, the researchers weren’t about to miss any opportunities and utilized gravitational lensing to aid in their findings.

This montage combines data from ALMA with images from the NASA/ESA Hubble Space Telescope, for five distant galaxies. The ALMA images, represented in red, show the distant, background galaxies, being distorted by the gravitational lens effect produced by the galaxies in the foreground, depicted in the Hubble data in blue. The background galaxies appear warped into rings of light known as Einstein rings, which encircle the foreground galaxies. Credit:ALMA (ESO/NRAO/NAOJ), J. Vieira et al.
This montage combines data from ALMA with images from the NASA/ESA Hubble Space Telescope, for five distant galaxies. The ALMA images, represented in red, show the distant, background galaxies, being distorted by the gravitational lens effect produced by the galaxies in the foreground, depicted in the Hubble data in blue. The background galaxies appear warped into rings of light known as Einstein rings, which encircle the foreground galaxies. Credit:ALMA (ESO/NRAO/NAOJ), J. Vieira et al.

“These beautiful pictures from ALMA show the background galaxies warped into multiple arcs of light known as Einstein rings, which encircle the foreground galaxies,” said Yashar Hezaveh (McGill University, Montreal, Canada), who led the study of the gravitational lensing. “We are using the massive amounts of dark matter surrounding galaxies half-way across the Universe as cosmic telescopes to make even more distant galaxies appear bigger and brighter.”

Just how bright is bright? According to the news release, the analysis of the distortion has shown that a portion of these far-flung, star-forming galaxies could be as bright as 40 trillion Suns… then magnified up to 22 times more through the aid of gravitational lensing.

“Only a few gravitationally lensed galaxies have been found before at these submillimetre wavelengths, but now SPT and ALMA have uncovered dozens of them.” said Carlos De Breuck (ESO), a member of the team. “This kind of science was previously done mostly at visible-light wavelengths with the Hubble Space Telescope, but our results show that ALMA is a very powerful new player in the field.”

“This is an great example of astronomers from around the world collaborating to make an amazing discovery with a state-of-the-art facility,” said team member Daniel Marrone (University of Arizona, USA). “This is just the beginning for ALMA and for the study of these starburst galaxies. Our next step is to study these objects in greater detail and figure out exactly how and why they are forming stars at such prodigious rates.”

Bring the house lights back up, please. As ALMA peers ever further into the past, maybe one day we’ll catch our own selves… looking back.

Posted on by David Dickinson

Pulsar Jackpot Scours Old Data for New Discoveries

Space Shuttle Atlantis passes behind the Parkes radio telescope after final undocking from the International Space Station in July 2011. (Image Copyright: John Sarkissian; used with permission).

Chalk another one up for Citizen Science.  Earlier this month, researchers announced the discovery of 24 new pulsars. To date, thousands of pulsars have been discovered, but what’s truly fascinating about this month’s discovery is that came from culling through old data using a new method.

A pulsar is a dense, highly magnetized, swiftly rotating remnant of a supernova explosion. Pulsars where first discovered by Jocelyn Bell Burnell and Antony Hewish in 1967. The discovery of a precisely timed radio beacon initially suggested to some that they were the product of an artificial intelligence. In fact, for a very brief time, pulsars were known as LGM’s, for “Little Green Men.” Today, we know that pulsars are the product of the natural death of massive stars.

The data set used for the discovery comes from the Parkes 64-metre radio observatory based out of New South Wales, Australia. The installation was the first to receive telemetry from the Apollo 11 astronauts on the Moon and was made famous in the movie The Dish.  The Parkes Multi-Beam Pulsar Survey (PMPS) was conducted in the late 1990’s, making thousands of 35-minute recordings across the plane of the Milky Way galaxy. This survey turned up over 800 pulsars and generated 4 terabytes of data. (Just think of how large 4 terabytes was in the 90’s!)

Artist's conception of a pulsar. (Credit: NASA/GSFC).
Artist’s conception of a pulsar. (Credit: NASA/GSFC).

The nature of these discoveries presented theoretical astrophysicists with a dilemma. Namely, the number of short period and binary pulsars was lower than expected. Clearly, there were more pulsars in the data waiting to be found.

Enter Citizen Science. Using a program known as Einstein@Home, researchers were able to sift though the recordings using innovative modeling techniques to tease out 24 new pulsars from the data.

“The method… is only possible with the computing resources provided by Einstein@Home” Benjamin Knispel of the Max Planck Institute for Gravitational Physics told the MIT Technology Review in a recent interview. The study utilized over 17,000 CPU core years to complete.

Einstein@Home screenshot. (Credit: LIGO Consortium).
Einstein@Home screenshot. (Credit: LIGO Consortium).

Einstein@Home is a program uniquely adapted to accomplish this feat. Begun in 2005, Einstein@Home is a distributed computing project which utilizes computing power while machines are idling to search through downloaded data packets. Similar to the original distributed computing program SETI@Home which searches for extraterrestrial signals, Einstein@Home culls through data from the LIGO (Laser Interferometer Gravitational Wave Observatory) looking for gravity waves. In 2009, the Einstein@Home survey was expanded to include radio astronomy data from the Arecibo radio telescope and later the Parkes observatory.

Among the discoveries were some rare finds. For example, PSR J1748-3009 Has the highest known dispersion measure of any millisecond pulsar (The dispersion measure is the density of free electrons observed moving towards the viewer). Another find, J1750-2531 is thought to belong to a class of intermediate-mass binary pulsars. 6 of the 24 pulsars discovered were part of binary systems.

These discoveries also have implications for the ongoing hunt for gravity waves by such projects as LIGO. Specifically, a through census of binary pulsars in the galaxy will give scientists a model for the predicted rate of binary pulsar mergers. Unlike radio surveys, LIGO seeks to detect these events via the copious amount of gravity waves such mergers should generate. Begun in 2002, LIGO consists of two gravity wave observatories, one in Hanford Washington and one in Livingston Louisiana just outside of Baton Rouge. Each LIGO detector consists of two 2 kilometre Fabry-Pérot arms in an “L” configuration which allow for ultra-precise measurements of a 200 watt laser beam shot through them.  Two detectors are required to pin-point the direction of an incoming gravity wave on the celestial sphere. You can see the orientation of the “L’s” on the display on the Einstein@Home screensaver. Two geographically separate detectors are also required to rule out local interference. A gravity wave from a galactic source would ripple straight through the Earth.

Arial view of LIGO Livingston. (Image credit: The LIGO Scientific Collaboration).
Arial view of LIGO Livingston. (Image credit: The LIGO Scientific Collaboration).

Such a movement would be tiny, on the order of 1/1,000th the diameter of a proton, unnoticed by all except the LIGO detectors. To date, LIGO has yet to detect gravity waves, although there have been some false alarms. Scientists regularly interject test signals into the data to see if system catches them. The lack of detection of gravity waves by LIGO has put some constraints on certain events. For example, LIGO reported a non-detection of gravity waves during the February 2007 short gamma-ray burst event GRB 070201. The event arrived from the direction of the Andromeda Galaxy, and thus was thought to have been relatively nearby in the universe. Such bursts are thought to be caused by neutron star and/or black holes mergers. The lack of detection by LIGO suggests a more distant event. LIGO should be able to detect a gravitational wave event out to 70 million light years, and Advanced LIGO (AdLIGO) is set to go online in 2014 and will increase its sensitivity tenfold.

The control room at LIGO Livingston. (Photo by Author).
The control room at LIGO Livingston. (Photo by Author).

Knowledge of where these potential pulsar mergers are by such discoveries as the Parkes radio survey will also give LIGO researchers clues of targets to focus on. “The search for pulsars isn’t easy, especially for these “quiet” ones that aren’t doing the equivalent of “screaming” for our attention,” Says LIGO Livingston Data Analysis and EPO Scientist Amber Stuver. The LIGO consortium developed the data analysis technique used by Einstein@Home. The direct detection of gravitational waves by LIGO or AdLIGO would be an announcement perhaps on par with CERN’s discovery of the Higgs Boson last year. This would also open up a whole new field of gravitational wave astronomy and perhaps give new stimulus to the European Space Agencies’ proposed Laser Interferometer Space Antenna (LISA) space-based gravity wave detector. Congrats to the team at Parkes on their discovery… perhaps we’ll have the first gravity wave detection announcement out of LIGO as well in years to come!

-Read the original paper on the discovery of 24 new pulsars here.

-Amber Stuver blogs about Einstein@Home & the spin-off applications of gravity wave technology at Living LIGO.

-Parkes radio telescope image is copyrighted and used with the permission of CSIRO Operations Scientist John Sarkissian.

-For a fascinating read on the hunt for gravity waves, check out Gravity’s Ghost.

 

Posted on by Jason Major

Gigantic Plasma Jets Pour From the Heart of Hercules A

Combined Hubble (optical) and VLA (radio) images show enormous radio jets shooting out from the galaxy Hercules A

Combined Hubble (optical) and VLA (radio) images show enormous radio jets shooting out from the galaxy Hercules A

Talk about pouring your heart out! Astronomers using Hubble’s Wide Field Camera 3 and the recently-upgraded Karl G. Jansky Very Large Array (VLA) radio telescope in New Mexico have identified gigantic jets of plasma, subatomic particles and magnetic fields blasting out of the center of Hercules A, a massive galaxy 2 billion light-years away.

The image above is a combination of optical images from Hubble and radio data gathered by the multi-dish VLA. If our eyes could see in the high-energy spectrum of radio, this is what Hercules A — the otherwise ordinary-looking elliptical galaxy in the center — would really look like.

(Of course, if we could see in radio our entire sky would be a very optically busy place!)

Also known as 3C 348, Hercules A is incredibly massive — nearly 1,000 times the mass of our Milky Way galaxy with a similarly scaled-up version of  a supermassive black hole at its center. Due to its powerful gravity and intense magnetic field Hercules A’s monster black hole is firing superheated material far out into space from its rotational poles. Although invisible in optical light, these jets are bright in radio wavelengths and are thus revealed through VLA observations.

Traveling close to the speed of light, the jets stretch for nearly 1.5 million light-years from both sides of the galaxy. Ring-shaped structures within them suggest that occasional strong outbursts of material have occurred in the past.

Announced on November 29, these findings illustrate the combined imaging power of two of astronomy’s most valuable and cutting-edge tools: Hubble and the newly-updated VLA. The video below shows how it was all done… check it out.

Read more on the NRAO press release here.

Image credits: NASA, ESA, S. Baum and C. O’Dea (RIT), R. Perley and W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA). Source: NRAO.

Posted on by Jenny Winder

Huge New ESA Tracking Station is Ready for Duty

Caption: ESA’s giant Malargüe tracking station Credits: ESA/S. Marti

To keep in contact with an ever growing armada of spacecraft ESA has developed a tracking station network called ESTRACK. This is a worldwide system of ground stations providing links between satellites in orbit and ESA’s Operations Control Centre (ESOC) located in Darmstadt, Germany. The core ESTRACK network comprises 10 stations in seven countries. Major construction has now been completed on the final piece of this cosmic jigsaw, one of the world’s most sophisticated satellite tracking stations at Malargüe, Argentina, 1000 km west of Buenos Aires.

ESA’s Core Network comprises 10 ESTRACK stations: Kourou (French Guiana), Maspalomas, Villafranca (Spain), Redu (Belgium), Santa Maria (Portugal), Kiruna (Sweden), Perth (Australia) which host 5.5-, 13-, 13.5- or 15-metre antennas. The new tracking station (DSA3) at Malargüe in Argentina, joins two other 35-metre deep-space antennas at New Norcia (DSA1) in Australia (completed in 2002) and Cebreros (DSA2) in Spain, (completed in 2005) to form the European Deep Space Network.

The essential task of ESTRACK stations is to communicate with missions, up-linking commands and down-linking scientific data and spacecraft status information. The tracking stations also gather radiometric data to tell mission controllers the location, trajectory and velocity of their spacecraft, to search for and acquire newly launched spacecraft, in addition to auto-tracking, frequency and timing control using atomic clocks and gathering atmospheric and weather data.

Deep-space missions can be over 2 million kilometres away from the Earth. Communicating at such distances requires highly accurate mechanical pointing and calibration systems. The 35m stations provide the improved range, radio technology and data rates required to send commands, receive data and perform radiometric measurements for current and next-generation exploratory missions such as Mars Express, Venus Express, Rosetta, Herschel, Planck, Gaia, BepiColombo, ExoMars, Solar Orbiter and Juice.

DSA3 is located at 1500m altitude in the clear Argentinian desert air, this and ultra-low-temperature amplifiers installed at the station, have meant that performance has exceeded expectations. The first test signals were received in June 2012 from Mars Express, over a distance of about 193 million km, proving that the station’s technology is ready for duty.

“Initial in-service testing with the Malargüe station shows excellent results.” “Our initial in-service testing with the Malargüe station shows excellent results,” says Roberto Maddè, ESA’s project manager for DSA 3 construction. “We have been able to quickly and accurately acquire signals from ESA and NASA spacecraft, and our station is performing better than specified.”

All three tracking stations are also equipped for radio science, which studies how matter, such as planetary atmospheres, affects the radio waves as they pass through. This can provide important information on the atmospheric composition of Mars, Venus or the Sun.

The tracking capability of all three ESA deep space stations also work in cooperation with partner agencies such as NASA and Japan’s JAXA, helping to boost science data return for all. The three Deep Space Antenna can be linked to the 7 stations comprising the Core Network as well as five other stations making up the larger Augmented Network and eleven additional stations that make up a global Cooperative Network with other space agencies from around the world.

Now that major construction is complete, teams are preparing DSA 3 for hand-over to operations, formal inauguration late this year and entry in routine service early in 2013.

Find out more about Malargüe and the Deep Space Antenna here and the other ESTRACK tracking stations here