The Race To Image Exoplanets Heats Up!

Thanks to the deployment of the Kepler mission, thousands of extrasolar planet candidates have been discovered. Using a variety of indirect detection methods, astronomers have detected countless gas giants, super Earths, and other assorted bodies orbiting distant stars. And one terrestrial planet (Proxima b) has even been found lurking in the closest star system to […]

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Japanese 3D Galaxy Map Confirms Einstein Was One Smart Dude

An international team of researchers have produced the largest  3-D map of the universe to date, which validates Einstein's theory of General Relativity. Credit: NAOJ/CFHT/ SDSS

On June 30th, 1905, Albert Einstein started a revolution with the publication of theory of Special Relativity. This theory, among other things, stated that the speed of light in a vacuum is the same for all observers, regardless of the source. In 1915, he followed this up with the publication of his theory of General Relativity, which asserted that gravity has a warping effect on space-time. For over a century, these theories have been an essential tool in astrophysics, explaining the behavior of the Universe on the large scale.

However, since the 1990s, astronomers have been aware of the fact that the Universe is expanding at an accelerated rate. In an effort to explain the mechanics behind this, suggestions have ranged from the possible existence of an invisible energy (i.e. Dark Energy) to the possibility that Einstein’s field equations of General Relativity could be breaking down. But thanks to the recent work of an international research team, it is now known that Einstein had it right all along.

Using the Fiber Multi-Object Spectrograph (FMOS) on the Subaru Telescope, the team – which was led by researchers from Japan’s Institute for the Physics and Mathematics of the Universe (Kavli IMPU) and the University of Tokyo – created the deepest 3-D map of the Universe to date. All told, this map contains some 3,000 galaxies and encompasses a volume of space measuring 13 billion light-years.

To test Einstein’s theory, the team  – which was led by Dr. Teppei Okumura, a Kavli IPMU Project Researcher – used information obtained by the FastSound Project over the past few years. As part of their effort to ascertain the origins of cosmic acceleration, this project relies on data collected by the Subaru telescope to create a survey that monitors the redshift of galaxies.

From what was observed over the course of 40 nights (between 2012 and 2014), the FastSound Survey was able to determine the on velocities and clustering of more than 3,000 distant galaxies. Measuring their redshift space distortions to see how fast they were moving, Okumura and his team were able to track the expansion of these galaxies out to a distance of 13 billion light-years.

This was an historic feat, seeing as how previous 3-D models of the Universe have not been able to reach beyond 10 billion light years. But thanks to the FMOS on the Subaru Telescope, which can analyze galaxies 12.4 to 14.7 billion light-years away, the team was able to break this record. They then compared the results to the kind of expansion predicted by Einstein’s theory, particularly the inclusion of his cosmological constant.

Originally introduced by Einstein in 1917 as an addition to his theory of General Relativity, the cosmological constant was basically a way to hold back gravity and achieve a static Universe. And while Einstein abandoned this theory when Edwin Hubble discovered that the Universe was expanding, it has since come to be an accepted part of the standard model of modern cosmology (known as the Lambda-CDM model).

What the research team found was that even at a distance of 13 billion light-years into the Universe, the rules of General Relativity are still valid. “We tested the theory of general relativity further than anyone else ever has,” said Dr. Okumura. “It’s a privilege to be able to publish our results 100 years after Einstein proposed his theory.”

These results have helped resolve something that astronomers have been puzzling over for decades, which was whether or not Einstein’s cosmological constant could be shown to be consistent with an expanding Universe. And while various experiments have confirmed that General Relativity did match observational data, they have been somewhat limited in the past.

For example, the Pound-Rebka experiment, which took place in 1960, was the first confirmation of Einstein’s theory. However, this experiment, and the many that followed in the ensuing decades, were either indirect or confined to the Solar System. A 2010 experiment conducted by researchers from Princeton University confirmed General Relativity to a distance of 7 billion light years.

But with this experiment, General Relativity has been confirmed to a distance of 13 billion light years, which accounts for the vast majority of the Universe that we can see (which is 13.8 billion light-years). It seems that even a century later, Einstein’s theories are still holding up. And considering that he once claimed that the cosmological constant was the “biggest blunder” of his scientific career!

Further Reading: Publications of the Astronomical Society of Japan

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Supermassive Black Holes In Distant Galaxies Are Mysteriously Aligned

A supermassive black hole has been found in an unusual spot: an isolated region of space where only small, dim galaxies reside. Image credit: NASA/JPL-Caltech

In 1974, astronomers detected a massive source of radio wave emissions coming from the center of our galaxy. Within a few decades time, it was concluded that the radio wave source corresponded to a particularly large, spinning black hole. Known as Sagittarius A, this particular black hole is so large that only the designation “supermassive” would do. Since its discovery, astronomers have come to conclude that supermassive black holes (SMBHs) lie at the center of almost all of the known massive galaxies.

But thanks to a recent radio imaging by a team of researchers from the University of Cape Town and University of the Western Cape, in South Africa, it has been further determined that in a region of the distant universe, the SMBHs are all spinning out radio jets in the same direction. This finding, which shows an alignment of the jets of galaxies over a large volume of space, is the first of its kind, and could tell us much about the early Universe.

This research, which appeared recently in the Monthly Notices of the Royal Astronomical Society, was made possible thanks to a three-year deep radio imaging survey conducted by the Giant Metrewave Radio Telescope (GMRT) in India. After examining the radio waves coming from a region of space called ELAIS-N1, the South African research team found that the jets being produced by these galaxies were all in alignment.

This finding could only be explained by venturing that the SMBHs creating them were all spinning in the same direction, which in turn reveals something rather interesting about how these black holes came to be. In essence, the only likely reason why multiple SMBHs could be spinning in the same direction over a large volume of space is if they were the result of primordial mass fluctuations in the early universe.

As Prof. Andrew Russ Taylor – the joint UWC/UCT SKA Chair, Director of the recently-launched Inter-University Institute for Data Intensive Astronomy, and principal author of the Monthly Notices study – explained: “Since these black holes don’t know about each other, or have any way of exchanging information or influencing each other directly over such vast scales, this spin alignment must have occurred during the formation of the galaxies in the early universe.”

This was rather surprising, and something the research team wasn’t prepared for. Initially, the goal of the project was to explore the faintest radio sources in the universe using the latest generation of radio telescopes; which, it was hoped, would provide a preview of what the next-generation of telescopes like South Africa’s MeerKAT telescope and the Square Kilometre Array (SKA) will provide once they go online.

While previous studies have shown that there are deviations in the orientations of certain galaxies, this was the first time that astronomers were able to use the jets produced by the SMBA holes to reveal their alignments. After noting the symmetry that was apparent between them, the research team considered several options as to why an alignment in galaxies (even on scales larger than galaxy clusters) might be.

However, it is important to note that a large-scale spin distribution of this kind has never been predicted by theories. Such an unknown phenomenon certainly presents a challenge when it comes to prevailing theories about the origins of the Universe, which will have to be revised somewhat to account for this.

While earlier studies have detected deviations from uniformity in the orientations of galaxies, this was the first time that radio jets were used to measure their alignment. This was made possible thanks to the sensitivity of the radio images used, which also benefitted from the fact that measurements of the intensity of radio emissions are not effected by things like scattering, extinction and Faraday Rotation (which may have effected other studies).

Furthermore, the presence of alignments of this nature could shed light on the orientation and evolution of these galaxies, particularly in relation to large-scale structures. They could also help astronomer to learn more about the motions in the primordial matter fluctuations that gave rise to the current structure of the Universe. As Taylor and the other authors of the paper also note, it will be interesting to compare this with predictions of angular momentum structure from universe simulations.

In recent years, several simulations have been produced to model the large-sale structure of the Universe and how it evolved. These include, but are not limited to, the FastSound project – which has been surveying galaxies in the Universe using the Subaru Telescope’s Fiber Multi-Object Spectrograph (FMOS) – and the DESI Project, which will rely on the Mayall Telescope at the Kitt Peak National Observatory in Arizona to chart the history of the Universe going back 11 billion years and create an extremely precise 3D map.

And then there’s the Australian Square-Kilometer Array Pathfinder (ASKAP), a radio telescope currently being commissioned by the Commonwealth Scientific and Industrial Research Organization (CSIRO) at the Murchison Radio-astronomy Observatory (MRO) in Western Australia. When completed, the ASKAP array will combine fast survey speed and high sensitivity to study the early Universe.

In the coming years, these projects, combined with this new information about the alignments of supermassive black holes, are likely to shed some serious light on how the Universe came to be, from creation to the present day. As Taylor puts it, “We’re beginning to understand how the large-scale structure of the universe came about, starting from the Big Bang and growing as a result of disturbances in the early universe, to what we have today, and that helps us explore what the universe of tomorrow will be like.”

Further Reading: Royal Astronomical Society

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The Early Universe Was All About Galactic Hook Ups

In about 4 billion years, scientists estimate that the Andromeda and the Milky Way galaxies are expected to collide, based on data from the Hubble Space Telescope. And when they merge, they will give rise to a super-galaxy that some are already calling…

Subaru Telescope Spots Galaxies From The Early Universe

It’s an amazing thing, staring into deep space with the help of a high-powered telescope. In addition to being able to through the vast reaches of space, one is also able to effectively see through time. Using the Subaru Telescope’s Suprime-Cam, a team of astronomers has done just that. In short, they looked back 13 […]