Gravitational Lensing Archives

July 31, 2014December 23, 2015 by Shannon Hall

Hubble Spots Farthest Lensing Galaxy Yet

Credit: NASA, ESA, K.-V. Tran (Texas A&M University), and K. Wong (Academia Sinica Institute of Astronomy & Astrophysics)

Sometimes there’s a chance alignment — faraway in the universe, where objects are separated by unimaginable distances measured in billions of light-years — when a galaxy cluster in the foreground intersects light from an even more distant object. The conjunction plays visual tricks, where the galaxy cluster acts like a lens, appearing to magnify and bend the distant light.

The rare cosmic alignment can bring the distant universe into view. Now, astronomers have stumbled upon a surprise: they’ve detected the most distant cosmic magnifying glass yet.

Seen above as it looked 9.6 billion years ago, this monster elliptical galaxy breaks the previous record holder by 200 million light-years. It’s bending, distorting and magnifying the distant spiral galaxy, whose light has taken 10.7 billion years to reach Earth.

“When you look more than 9 billion years ago in the early universe, you don’t expect to find this type of galaxy-galaxy lensing at all,” said lead researcher Kim-Vy Tran from Texas A&M University in a Hubble press release.

“Imagine holding a magnifying glass close to you and then moving it much farther away. When you look through a magnifying glass held at arm’s length, the chances that you will see an enlarged object are high. But if you move the magnifying glass across the room, your chances of seeing the magnifying glass nearly perfectly aligned with another object beyond it diminishes.”

The team was studying star formation in data collected by the W. M. Keck Observatory in Hawai’i, when they came across a strong detection of hot hydrogen gas that appeared to arise form a massive, bright elliptical galaxy. It struck the team as odd. Hot hydrogen is a clear sign of star birth, but it was detected in a galaxy that looked far too old to be forming new stars.

“I was very surprised and worried,” Tran recalled. “I thought we had made a major mistake with our observations.”

So Tran dug through archived Hubble images, which revealed a smeared, blue object next to the larger elliptical. It was the clear signature of a gravitational lens.

“We discovered that light from the lensing galaxy and from the background galaxy were blended in the ground-based data, which was confusing us,” said coauthor Ivelina Momcheva of Yale University. “The Keck spectroscopic data hinted that something interesting was going on here, but only with Hubble’s high-resolution spectroscopy were we able to separate the lensing galaxy from the more distant background galaxy and determine that the two were at different distances. The Hubble data also revealed the telltale look of the system, with the foreground lens in the middle, flanked by a bright arc on one side and a faint smudge on the other — both distorted images of the background galaxy. We needed the combination of imaging and spectroscopy to solve the puzzle.”

By gauging the intensity of the background galaxy’s light, the team was able to measure the giant galaxy’s total mass. All in all it weighs 180 billion times more than our Sun. Although this may seem big, it actually weighs four times less than the Milky Way galaxy.

“There are hundreds of lens galaxies that we know about, but almost all of them are relatively nearby, in cosmic terms,” said lead author Kenneth Wong from the Academia Sinica Institute of Astronomy & Astrophysics. “To find a lens as far away as this one is a very special discovery because we can learn about the dark-matter content of galaxies in the distant past. By comparing our analysis of this lens galaxy to the more nearby lenses, we can start to understand how that dark-matter content has evolved over time.”

Interestingly, the lensing galaxy is underweight in terms of its dark-matter content. In the past, astronomers have assumed that dark matter and normal matter build up equally in a galaxy over time. But this galaxy, suggests this is not the case.

The team’s results appeared in the July 10 issue of The Astrophysical Journal Letters and is available online.

July 25, 2014December 23, 2015 by Shannon Hall

Mapping Dark Matter 4.5 Billion Light-years Away

This image shows the galaxy MCS J0416.1–2403, one of six clusters targeted by the Hubble Frontier Fields programme. The blue in this image is a mass map created by using new Hubble observations combined with the magnifying power of a process known as gravitational lensing. In red is the hot gas detected by NASA’s Chandra X-Ray Observatory and shows the location of the gas, dust and stars in the cluster. The matter shown in blue that is separate from the red areas detected by Chandra consists of what is known as dark matter, and which can only be detected directly by gravitational lensing.Credit: ESA/Hubble, NASA, HST Frontier Fields. Acknowledgement: Mathilde Jauzac (Durham University, UK) and Jean-Paul Kneib (École Polytechnique Fédérale de Lausanne, Switzerland).

The Milky Way measures 100 to 120 thousand light-years across, a distance that defies imagination. But clusters of galaxies, which comprise hundreds to thousands of galaxies swarming under a collective gravitational pull, can span tens of millions of light-years.

These massive clusters are a complex interplay between colliding galaxies and dark matter. They seem impossible to map precisely. But now an international team of astronomers using the NASA/ESA Hubble Space Telescope has done exactly this — precisely mapping a galaxy cluster, dubbed MCS J0416.1–2403, 4.5 billion light-years away.

“Although we’ve known how to map the mass of a cluster using strong lensing for more than twenty years, it’s taken a long time to get telescopes that can make sufficiently deep and sharp observations, and for our models to become sophisticated enough for us to map, in such unprecedented detail, a system as complicated as MCS J0416.1–2403,” said coauthor Jean-Paul Kneib in a press release.

Measuring the amount and distribution of mass within distant objects can be extremely difficult. Especially when three quarters of all matter in the Universe is dark matter, which cannot be seen directly as it does not emit or reflect any light. It interacts only by gravity.

But luckily large clumps of matter warp and distort the fabric of space-time around them. Acting like lenses, they appear to magnify and bend light that travels past them from more distant objects.

This effect, known as gravitational lensing, is only visible in rare cases and can only be spotted by the largest telescopes. Even galaxy clusters, despite their massive size, produce minimal gravitational effects on their surroundings. For the most part they cause weak lensing, making even more distant sources appear as only slightly more elliptical across the sky.

However, when the alignment of the cluster and distant object is just right, the effects can be substantial. The background galaxies can be both brightened and transformed into rings and arcs of light, appearing several times in the same image. It is this effect, known as strong lensing, which helped astronomers map the mass distribution in MCS J0416.1–2403.

“The depth of the data lets us see very faint objects and has allowed us to identify more strongly lensed galaxies than ever before,” said lead author Dr Jauzac. “Even though strong lensing magnifies the background galaxies they are still very far away and very faint. The depth of these data means that we can identify incredibly distant background galaxies. We now know of more than four times as many strongly lensed galaxies in the cluster than we did before.”

Using Hubble’s Advanced Camera for Surveys, the astronomers identified 51 new multiply imaged galaxies around the cluster, quadrupling the number found in previous surveys. This effect has allowed Jauzac and her colleagues to calculate the distribution of visible and dark matter in the cluster and produce a highly constrained map of its mass.

The total mass within the cluster is 160 trillion times the mass of the Sun, with an uncertainty of 0.5%. It’s the most precise map ever produced.

But Jauzac and colleagues don’t plan on stopping here. An even more accurate picture of the galaxy cluster will have to include measurements from weak lensing as well. So the team will continue to study the cluster using ultra-deep Hubble imaging.

They will also use ground-based observatories to measure any shifts in galaxies’ spectra and therefore note the velocities of the contents of the cluster. Combining all measurements will not only further enhance the detail, but also provide a 3D model of the galaxies within the cluster, shedding light on its history and evolution.

This work has been accepted for publication in the Monthly Notices of the Royal Astronomy and is available online.

April 25, 2014December 23, 2015 by Elizabeth Howell

Gallery: Incredible Mirages In Space Show Dark Matter, Supernovas And Galaxies

This artist’s impression of a supernova shows the layers of gas ejected prior to the final deathly explosion of a massive star. Credit: NASA/Swift/Skyworks Digital/Dana Berry

How can an exploding star appear far brighter than expected? This question vexed astronomers since the discovery of PS1-10afx, supernova that was about 30 times more luminous than other Type 1A supernovas. Astronomers have just confirmed in Science that it was likely due to well-known illusion in space.

The mirage is called a gravitational lens that happens when a huge object in the foreground (like a galaxy) bends the light of an object in the background. Astronomers use this trick all the time to spy on galaxies and even to map dark matter, the mysterious substance believed to make up most of the universe.

Check out some spectacular images below of the phenomenon in action.

Canada-France-Hawaii-Telescope (CFHT) image of the field before the supernova PS1-10afx. (Credit: Kavli IPMU / CFHT)

Dark matter in the Bullet Cluster. Otherwise invisible to telescopic views, the dark matter was mapped by observations of gravitational lensing of background galaxies. Credit: X-ray: NASA/CXC/CfA/ M.Markevitch et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/ D.Clowe et al. Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.;

Hubble Space Telescope image shows Einstein ring of one of the SLACS gravitational lenses, with the lensed background galaxy enhanced in blue. A. Bolton (UH/IfA) for SLACS and NASA/ESA.

The image is made from HST data and shows the four lensed images of the dusty red quasar, connected by a gravitational arc of the quasar host galaxy. The lensing galaxy is seen in the centre, between the four lensed images. Credit: John McKean/HST Archive data

The HST WFPC2 image of gravitational lensing in the galaxy cluster Abell 2218, indicating the presence of large amount of dark matter (credit Andrew Fruchter at STScI).

April 17, 2014December 23, 2015 by Nancy Atkinson

New Hubble View Shows Objects a Billion Times Fainter Than Your Eyes Can See

This 14-hour exposure from the Hubble Space Telescope zooms in on a galaxy cluster and shows objects around a billion times fainter than can be seen with the naked eye. Credit: NASA/ESA. — Hubble’s images might look flat, but this one shows a remarkable depth of field that lets us see more than halfway to the edge of the observable Universe. Credit: NASA/ESA.

While this image isn’t as deep as the Hubble Deep Field, this 14-hour exposure by the Hubble Space Telescope shows objects around a billion times fainter than what can be seen with the human eyes alone. Astronomers say this image also offers a remarkable depth of field that lets us see more than halfway to the edge of the observable Universe.

As well, this image also provides an extraordinary cross-section of the Universe in both distance and age, showing objects at different distances and stages in cosmic history, and ranges from some of our nearest neighbors to objects seen in the early years of the Universe.

Annotated image of the field around CLASS B1608+656. Credit: NASA/ESA.

Most of the galaxies visible here are members of a huge cluster called CLASS B1608+656, which lies about five billion light-years away. But the field also contains other objects, both significantly closer and far more distant, including quasar QSO-160913+653228 which is so distant its light has taken nine billion years to reach us, two thirds of the time that has elapsed since the Big Bang.

Since the Hubble Deep Field combined 10 days of exposure and the eXtreme Deep Field, or XDF was assembled by combining ten years of observations (with over 2 million seconds of exposure time), this image at 14 hours of exposure may seem “small.” But it shows the power of the Hubble Space Telescope.

Also of note is that this image was “found” in the Hubble Hidden Treasures vault — where members of the public are able to search Hubble’s science for the best overlooked images that have never been seen by a general audience. This image of CLASS B1608+656 has been well-studied by scientists over the years, but this is the first time it has been published in full online.

Take a zooming view through the image in the video below and read more about this image here.

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Source: Hubble ESA

October 17, 2013December 23, 2015 by Elizabeth Howell

Here’s A Nine-Billion-Year Old Gravitational Lens In Space

Here’s a picture of what deflected light looks like from 9.4 billion years away. This is the most faraway “gravitational lens” that we know of, and a demonstration of how a galaxy can bend the light of an object behind it. The phenomenon was first predicted by Einstein, and is a handy way of measuring mass (including the mass of mysterious dark matter.)

“The discovery was completely by chance,” stated Arjen van der Wel, who is with the Max Planck Institute for Astronomy in Heidelberg, Germany.

“I had been reviewing observations from an earlier project when I noticed a galaxy that was decidedly odd. It looked like an extremely young galaxy, but it seemed to be at a much larger distance than expected. It shouldn’t even have been part of our observing program.”

The alignment between object J1000+0221 and the object in behind is so perfect that you can see rings of light being formed in the image. Scientists previously believed this kind of lens would happen very rarely. This leaves two possibilities: that the astronomy team was lucky, or there are way more young galaxies than previously thought.

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.

“Gravitational lenses are the result of a chance alignment. In this case, the alignment is very precise,” a press release on the discovery stated.

“To make matters worse, the magnified object is a starbursting dwarf galaxy: a comparatively light galaxy … but extremely young (about 10-40 million years old) and producing new stars at an enormous rate. The chances that such a peculiar galaxy would be gravitationally lensed is very small. Yet this is the second starbursting dwarf galaxy that has been found to be lensed.”

“This has been a weird and interesting discovery,” added van der Wel. “It was a completely serendipitous find, but it has the potential to start a new chapter in our description of galaxy evolution in the early universe.”

The research will be available soon in the Astrophysical Journal; in the meantime, check out a preprint version on Arxiv.

Source: Hubble European Space Agency Information Centre

October 15, 2013December 23, 2015 by Shannon Hall

Novel Strategy May Help Target Extraterrestrial Intelligent Life

Discovering life beyond Earth might just be the holy grail of science. And even though we have yet to find evidence for little green men or blobs of bacteria, astronomers continue to search for elusive signs of life.

A novel strategy may help astronomers better target extraterrestrial intelligent life. Dr. Michael Gillon, of the University of Liege in Belgium, proposes an approach that would monitor the regions of nearby stars to search for interstellar communication devices.

The most common method in the search for extraterrestrial intelligence (abbreviated as SETI) is the use of giant radio dishes to scan the stars, listening for possible faint signals coming from distant civilizations.

While the SETI institute has been hard at work since 1959 we haven’t chanced upon a signal yet. But that doesn’t mean we’re alone or that we should stop looking.

Even without a confirmed extraterrestrial signal, most astronomers would argue that recent discoveries have strongly reinforced the hypothesis that extraterrestrial life may just be abundant in the Universe. With the help of the Kepler Space Telescope we have learned that planets are plentiful throughout the Milky Way. With most stars harboring at least one planet, it’s conceivable that a few of those planets will have the right conditions for life.

So why haven’t we detected extraterrestrial intelligent life? Why do we have this glaring Fermi Paradox — the apparent contradiction between the high probability of extraterrestrial civilizations’ existence and the lack of contact with such civilizations?

One hypotheses to explain the famous Fermi Paradox is that self-replicating probes could have explored the whole Galaxy, including our Solar System, but we just haven’t detected them yet. A self-replicating probe is one sent to a nearby planetary system where it would mine raw materials to create a replica of itself that would then head towards other nearby systems, continuing to replicate itself along the way.

While our own technological civilization is less than two hundred years old, we have already sent robotic probes to a large number of bodies in our Solar System and beyond. Our furthest-reaching probe, Voyager 1, just made it to interstellar space. But it took it over 40 years.

“We are still far from being able to build an actual self-replicating interstellar spaceship, but only because our technology is not mature enough, and not because of an obvious physical limitation,” Dr. Gillon told Universe Today.

While we cannot currently send self-replicating probes to the nearest stars in a reasonable amount of time, nothing excludes this as a reachable future project, or a project already completed by extraterrestrial intelligent life.

This study further proposes that probes from neighboring stellar systems could use the stars they orbit as gravitational lenses to communicate efficiently with each other.

The coordination of probes to explore the Galaxy would be very inefficient unless they had the ability to directly communicate with one another. The vastness and structure of the Milky Way makes this seemingly impossible. By the time a signal reached a very distant star it would be highly diluted.

However, any star is massive enough to bend and amplify light. This process, gravitational lensing, is extremely powerful. “It means that the Sun (and any other star) is an antenna much more powerful than we could ever build,” says Dr. Gillon.

Based on this method, interstellar communication devices will exist along the line that connects one star to another. We now know exactly where to look, and even where to send messages.

Could this novel idea provide a new mission for SETI?

“A negative result wouldn’t tell us very much,” explains Dr. Gillon. “But a positive result would represent one of the most important discoveries of all time.”

The paper has been accepted for publication in Acta Astronautica and is available for download here.

June 25, 2013April 26, 2016 by Tammy Plotner

Astronomers Spy Early Galaxies Caught In A Cosmic Spiderweb

The Spiderweb, imaged by the Hubble Space Telescope – a central galaxy (MRC 1138-262) surrounded by hundreds of other star-forming 'clumps'. Credit: NASA, ESA, George Miley and Roderik Overzier (Leiden Observatory)

Once upon a time, when the Universe was just about three billion years old, galaxies started to form. Now astronomers using a CSIRO radio telescope have captured evidence of the raw materials these galaxies used to fashion their first stars… cold molecular hydrogen gas, H2. Even though we can’t see it directly, we know it is there by using another gas that reveals its presence – carbon monoxide (CO) – a radio wave emitter.

The telescope is CSIRO’s Australia Telescope Compact Array telescope near Narrabri, NSW. “It one of very few telescopes in the world that can do such difficult work, because it is both extremely sensitive and can receive radio waves of the right wavelengths,” says CSIRO astronomer Professor Ron Ekers.

One of the studies of these “raw” galaxies was performed by astronomer Dr. Bjorn Emonts of CSIRO Astronomy and Space Science. He and fellow researchers employed the Compact Array to observe and record a gigantic and distant amalgamation of “star forming clumps or proto-galaxies” which are congealing together to create a single massive galaxy. This framework is known as the “Spiderweb” and is theorized to be at least ten thousand million light years distant. The Compact Array radio telescope is capable of picking up the signature of star formation, giving astronomers vital clues about how early galaxies began star formation.

In blue, the carbon monoxide gas detected in and around the Spiderweb. Credit: B. Emonts et al (CSIRO/ATCA)

The “Spiderweb” was loaded. Here Dr. Emont and his colleagues found the molecular hydrogen gas fuel they were seeking. It covered an area of space almost a quarter of a million light-years across and contained at least sixty thousand million times the mass of the Sun! Surely this had to be the material responsible for the new stars seen sprinkled across the region. “Indeed, it is enough to keep stars forming for at least another 40 million years,” says Emonts.

In another research project headed by Dr. Manuel Aravena of the European Southern Observatory, the scientists measured the CO – the indicator of H2 – in two very distant galaxies. The signal of the faint radio waves was amped up by the gravitational fields of the additional galaxies – the “line of sight” members – which created gravitational lensing. Says Dr. Aravena, “This acts like a magnifying lens and allows us to see even more distant objects than the Spiderweb.”

Dr. Aravena’s team went to work measuring the amount of H2 in both of their study galaxies. One of these, SPT-S 053816-5030.8, produced enough radio emissions to allow them to infer how quickly it was forming stars – “an estimate independent of the other ways astronomers measure this rate.”

The Compact Array was tuned in. Thanks to an upgrade which increased its bandwidth – the amount of the radio spectrum which can be observed at any particular time – it is now sixteen times stronger and capable of reaching a range from 256 MHz to 4 GHz. That makes it a very sensitive ear!

“The Compact Array complements the new ALMA telescope in Chile, which looks for the higher-frequency transitions of CO,” says Ron Ekers.

Original Story Source: CSIRO News Release

June 13, 2013April 26, 2016 by Elizabeth Howell

Where Is Dark Matter Most Dense? Subaru Telescope Gets Some Hints

The Subaru Telescope. Credit: National Astronomical Observatory of Japan

Put another checkmark beside the “cold dark matter” theory. New observations by Japan’s Subaru Telescope are helping astronomers get a grip on the density of dark matter, this mysterious substance that pervades the universe.

We can’t see dark matter, which makes up an estimated 85 percent of the universe, but scientists can certainly measure its gravitational effects on galaxies, stars and other celestial residents. Particle physicists also are on the hunt for a “dark matter” particle — with some interesting results released a few weeks ago.

The latest experiment with Subaru measured 50 clusters of galaxies and found that the density of dark matter is largest in the center of these clusters, and smallest on the outskirts. These measurements are a close match to what is predicted by cold dark matter theory, scientists said.

Cold dark matter assumes that this material can’t be observed in any part of the electromagnetic spectrum, the band of light waves that ranges from high-energy X-rays to low-energy infrared heat. Also, the theory dictates that dark matter is made up of slow-moving particles that, because they collide with each other infrequently, are cold. So, the only way dark matter interacts with other particles is by gravity, scientists have said.

To check this out, Subaru peered at “gravitational lensing” in the sky — areas where the light of background objects are bent around dense, massive objects in front. Galaxy clusters are a prime example of these super-dense areas.

Several dark matter maps: one based on a sample of 50 individual galaxy clusters (left), another looking at an average galaxy cluster (center), and another based on dark matter theory (right). Red is the highest concentration of dark matter, followed by yellow, green and blue. At right, in the middle, is a map based on cold dark matter theory that comes close to the average galaxy cluster observed with the Suburu Telescope. Credit: NAOJ/ASIAA/School of Physics and Astronomy, University of Birmingham/Kavli IPMU/Astronomical Institute, Tohoku University)

“The Subaru Telescope is a fantastic instrument for gravitational lensing measurements. It allows us to measure very precisely how the dark matter in galaxy clusters distorts light from distant galaxies and gauge tiny changes in the appearance of a huge number of faint galaxies,” stated Nobuhiro Okabe, an astronomer at Academia Sinica in Taiwan who led the study.

Next, the team members could compare where the matter was most dense with that predicted by cold dark matter theory. To do that, they measured 50 of the most massive, known clusters of galaxies. Then, they measured the “concentration parameter”, or the cluster’s average density.

“They found that the density of dark matter increases from the edges to the center of the cluster, and that the concentration parameter of galaxy clusters in the near universe aligns with CDM theory,” stated the National Astronomical Observatory of Japan.

The next step, researchers stated, is to measure dark matter density in the center of the galaxy clusters. This could reveal more about how this substance behaves. Check out more about this study in Astrophysical Journal Letters.

Sourcs: National Astronomical Observatory of Japan

June 5, 2013December 23, 2015 by Nancy Atkinson

Watch Live Webcast: Space Warps

Want to join the hunt for new galaxies? During a special G+ Hangout today, June 5, a team of astronomers will share how you can help them find faint and distant galaxies by joining a search they’ve called “Space Warps.” This is a new project from the Zooniverse. The team of astronomers will discuss gravitational lensing, a strange phenomenon that actually makes it possible for us to see a galaxy far away and otherwise hidden by clusters of galaxies in front of them. They will also answer your questions about their ongoing search for distant galaxies, what this reveals about the cosmos, and how astronomers are beginning to fill out our picture of the universe.

You can watch in the window below, and the webcast starts at 21:00 UTC (2:00 p.m. PDT, 5:00 pm EDT). You can take part in thise live Google+ Hangout, and have your questions answered by submitting them before or during the webcast. Email questions to [email protected] or send a message on Twitter with the hashtag #KavliAstro.

If you miss it live, you can watch the replay below, as well.

The participants:
• ANUPREETA MORE is a co-Principal Investigator of Space Warps and a postdoctoral fellow at the Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo.
• PHILIP MARSHALL is a researcher at the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University and SLAC.
• ARFON SMITH is Director of Citizen Science at the Adler Planetarium in Chicago and Technical Lead of Zooniverse (www.zooniverse.org).

You can also get more info at the Kavli Foundation, and visit the Space Warps website here.

May 28, 2013December 23, 2015 by Elizabeth Howell

Early Galaxies Churned Out Stars Like Crazy

The Southern Cross, the Milky Way, and the Large Magellanic Cloud shine above the Atacama Large Millimeter/submillimeter Array (ALMA) as it observes on a clear night sky during its Early Science phase. Image credit: C. Padilla, NRAO/AUI/NSF

Talk about an assembly line! Some early-stage galaxies created stars thousands of times faster than our Milky Way does today, according to new research. And it’s puzzling astronomers.

“We want to understand how and why these galaxies are forming stars at such incredibly fast rates, so soon after the Big Bang,” stated Scott Chapman of Dalhousie University, one of the researchers behind the discovery. “This could partially answer how our own galaxy, the Milky Way, was born billions of years ago.”

This is just a hint of the high-definition view we’ll receive from Chile’s Atacama Large Millimeter/submillimeter Array (ALMA), its astronomers promise, since the array of dozens of telescopes was officially inaugurated this spring. (ALMA has been working for years, but slowly adding telescopes and definition as it goes.)

There were actually three papers released today about ALMA. So what did the observatory find out this time? Here’s the nut graf:

Gravitational microlensing method requires that you have two stars that lie on a straight line in relation to us here on Earth. Then the light from the background star is amplified by the gravity of the foreground star, which thus acts as a magnifying glass.

– The observed galaxies are “gravitationally lensed”. Galaxies are so massive that they can bend light from other galaxies, if put in the right spot with respect to Earth. We’ve seen this effect over and over again with the Hubble Space Telescope, but observations are less well-known in the millimeter spectrum of light in which ALMA observes. “Models of lens geometries in the sample indicate that the background objects are ultra-luminous infrared galaxies, powered by extreme bursts of star formation,” stated a Nature paper on the discovery.

– These galaxies are further away than we thought. By measuring the time it takes light from carbon monoxide molecules to reach us, the astronomers concluded these galaxies are much further away than previously measured, with some reaching as far back as 12 billion light-years away. (That’s just 1.7 billion years after the Big Bang created the universe.)

– The galaxies put star creation on fast-forward. Looking back that far is like looking in a time machine — we can see things that were happening only 1 billion years after the Big Bang. At the time, those galaxies were as bright as 40 trillion suns and created new stars at an extreme rate of 4,000 suns per year. (That, by the way, is 4,000 times faster than what our own galaxy does.)

You can read more about these results in Nature and the Astrophysical Journal (here and here.)

Source: Canadian Astronomical Society (CASCA)