Three Telescopes track laws of Nature 10 billion years ago

Astronomers have focused the three most powerful optical telescopes in the world on a single point in the sky to test one of Nature's fundamental laws.

An international team, led by researchers from Swinburne University of Technology, observed a quasar, the extremely bright surroundings of a supermassive black hole, using the ESO's Very Large Telescope (VLT) in Chile and the W M Keck Observatory and Subaru Telescope, both in Hawaii.

The quasar light passed through three different galaxies, some 10, 9 and 8 billion years ago, on its way to Earth.

These galaxies absorbed a characteristic pattern of colours out of the quasar light, revealing the strength of electromagnetism, one of Nature's four fundamental forces, in the early and distant Universe.

"We spread the light very finely into its component colours, producing a rainbow with a `barcode' pattern of missing colours."

"We can then measure electromagnetism by `reading' this barcode," said Tyler Evans, Swinburne PhD student and lead author of the new study.

"We need to compare the barcode patterns from three telescopes to be sure they're right."

Previous studies, using a large number of quasars, had found hints that electromagnetism might be different in the distant reaches of the Universe, slightly weaker or slightly stronger than on Earth.

"If that's true, we'd need a completely new understanding of fundamental physics," Mr Evans said.

"So it's crucial to triple check whether and how the telescopes are distorting the barcodes."

By comparing the barcodes, the researchers found small differences between the telescopes.

"The beauty of our method is that we can also use the barcodes themselves to correct each telescope accurately," said Swinburne Associate Professor Michael Murphy, who co-authored the work.

"Once corrected, all three telescopes gave the same answer: electromagnetism hasn't changed, within a few parts per million, over 10 billion years. I think this is the most reliable measurement of its kind so far".

The team is now making similarly careful measurements in many other galaxies.

"With our new techniques and new quasar observations recently complete, we can make the most accurate check to see whether electromagnetism's strength really is changing or not," Associate Professor Murphy said.

More information: "The UVES Large Program for testing fundamental physics - III. Constraints on the fine-structure constant from 3 telescopes." T. M. Evans, M. T. Murphy, J. B. Whitmore, T. Misawa, M. Centurion, S. D'Odorico, S. Lopez, C. J. A. P. Martins, P. Molaro, P. Petitjean, H. Rahmani, R. Srianand, M. Wendt arXiv:1409.1923 [astro-ph.CO] arxiv.org/abs/1409.1923

Subaru Telescope: Traces of One of Universe's First Stars Detected

The most massive stars in the early universe would eject material high in iron when they exploded. 

Astronomers can read the composition of the next generation of stars to determine what made up their ancestors.

Credit: National Astronomical Observatory of Japan

An ancient star in the halo surrounding the Milky Way galaxy appears to contain traces of material released by the death of one of the universe's first stars, a new study reports.

The chemical signature of the ancient star suggests that it incorporated material blasted into space by a supernova explosion that marked the death of a huge star in the early universe, one that may have been 200 times more massive than the sun.

"The impact of very-massive stars and their explosions on subsequent star formation and galaxy formation should be significant," lead author Wako Aoki, of the National Astronomical Observatory of Japan, told Space.com by email.

Hidden giants
The first stars in the cosmos, known as Population III stars, formed from the hydrogen and helium that dominated the early universe.

Through nuclear fusion, other elements were forged in their hearts. At the end of their lifetimes, supernovas scattered these elements into the space around them, where the material was folded into the next generation of stars.

The universe's first massive stars would have been short-lived, so to determine their composition, scientists must examine the makeup of their offspring, stars that formed from the material distributed by their explosive deaths.

While numerical simulations have suggested that at least some of the first stars should have reached enormous proportions, no previous observational evidence had managed to confirm their existence.

Aoki and a team of scientists used the Subaru Telescope in Hawaii to perform follow-up observations of a large sample of low-mass stars with low quantities of what astronomers term "metals," elements other than hydrogen and helium. 

They identified SDS J0018-0939, an ancient star only 1,000 light-years from Earth.

"The low abundance of heavy elements suggests that this star is quite old — as old as 13 billion years," Aoki said.
(Scientists think the Big Bang that created the universe occurred approximately 13.8 billion years ago.)

The chemical composition of SDS J0018-0939 suggests it gobbled up the material blown off of a single massive ancient star, rather than several smaller bodies.

If multiple supernovas had provided the material that constructed the star, the "peculiar abundance ratios" in its interior would have been erased, Aoki said.

Volker Bromm of the University of Texas, Austin agrees, saying that SDS J0018 likely evolved from the material from a single star, which could have been more than 200 times as massive as the sun.

Bromm, who has performed theoretical studies on the properties of the first generation of stars and their supernova explosions, did not participate in the new study.

He authored a corresponding "News & Views" article that appeared with the research online today (Aug. 21) in the journal Science.

Signs of low-mass first-generation stars have appeared to be more plentiful in their descendants, which contain large amounts of carbon and other light elements, but until these results, scientists had detected no traces of their very massive siblings.

The scarcity suggested that low-mass stars were more numerous in the early universe.

"We have come to understand that the first stars had a range of masses, from a few solar masses, all the way up to 100 solar masses, or even more," Bromm told reporters.

"The typical, or average, mass is predicted to be somewhere close to a few tens of solar masses.".

A fluffy disk around a baby star

Artist’s rendition of the "fluffy" layer associated with the protoplanetary disk of RY Tau, including jets coming from the star. 

Although typical young stars like RY Tau are often associated with jets, they are not visible in the HiCIAO observations at this time. 

Credit: NAOJ

An international team of astronomers that are members of the Strategic Exploration of Exoplanets and Disks with Subaru Telescope (SEEDS) Project has used Subaru Telescope's High Contrast Instrument for the Subaru Next Generation Adaptive Optics (HiCIAO) to observe a disk around the young star RY Tau (Tauri).

The team's analysis of the disk shows that a "fluffy" layer above it is responsible for the scattered light observed in the infrared image.

Detailed comparisons with computer simulations of scattered light from the disk reveal that this layer appears to be a remnant of material from an earlier phase of stellar and disk development, when dust and gas were falling onto the disk.

Since 2009, the five-year SEEDS Project has focused on direct imaging of exoplanets, i.e., planets orbiting stars outside of our Solar System, and disks around a targeted total of 500 stars.

Planet formation, an exciting and active area for astronomical research, has long fascinated many scientists.

Disks of dust and gas that rotate around young stars are of particular interest, because astronomers think that these are the sites where planets form—in these so-called "protoplanetary disks."

Since young stars and disks are born in molecular clouds, giant clouds of dust and gas, the role of dust becomes an important feature of understanding planet formation; it relates not only to the formation of rocky, Earth-like planets and the cores of giant Jupiter-like planets but also to that of moons, planetary rings, comets, and asteroids.

As a part of the SEEDS Project, the current team of researchers used HiCIAO mounted on the Subaru Telescope to observe a possible planet-forming disk around the young star RY Tau.

This star is about 460 light years away from Earth in the constellation Taurus and is around half a million years old.

The disk has a radius of about 70 AU (10 billion kilometers), which is a few times larger than the orbit of Neptune in our own Solar System.

More information: Takami, M. et al, 2013, High-Contrast Near-Infrared Imaging Polarimetry of the Protoplanetary Disk around RY Tau, Astrophysical Journal, Vol. 772, paper 145.

Subaru Telescope: Pink Alien Planet GJ 504b Image Captured

Glowing a dark magenta, the newly discovered exoplanet GJ 504b weighs in with about four times Jupiter's mass, making it the lowest-mass planet ever directly imaged around a star like the sun.

This image is an artist's representation of the alien world. 

Credit: NASA's Goddard Space Flight Center/S. Wiessinger

Astronomers have snapped a photo of a pink alien world that's the smallest yet exoplanet found around a star like our sun.

The alien planet GJ 504b is a colder and bluer world than astronomers had anticipated and it likely has a dark magenta hue, infrared data from the Subaru Telescope in Hawaii revealed.

"If we could travel to this giant planet, we would see a world still glowing from the heat of its formation with a color reminiscent of a dark cherry blossom, a dull magenta," study researcher Michael McElwain, of NASA's Goddard Space Flight Center in Greenbelt, Md., said in a statement from the space agency.

Subaru Telescope: Cosmic giants shed new light on dark matter

Dark matter maps for 50 individual galaxy clusters (left), the average galaxy cluster (centre), and based on dark matter theory (right). 

The CDM theory (right, centre) is a close match with the average galaxy cluster observed with the Subaru telescope. 

The density of dark matter increases in the order of blue, green, yellow, red, and black colors. Credit: University of Birmingham

Astronomers at the University of Birmingham (UK), Academica Sinica in Taiwan, and the Kavli Institute of Physics and Mathematics of the Universe in Japan, have found new evidence that the mysterious dark matter that pervades our universe behaves as predicted by the 'cold dark matter' theory (CDM).

At a press conference today in Taipei the team of astronomers report their measurements of the density of dark matter in the most massive objects in the universe, namely galaxy clusters.

They found that the density of dark matter decreases gently from the centre of these cosmic giants out to their diffuse outskirts.

The fall in dark matter density from the centre to the outskirts agrees very closely with the CDM theory.

Almost eighty years after the first evidence for dark matter emerged from astronomy research, few scientists seriously doubt that it exists.

However astronomers cannot see dark matter directly in the night sky, and particle physicists have not yet identified the dark matter particle in their experiments.

"What is dark matter?"
This is still a big unanswered question facing astronomers and particle physicists, especially because there is strong evidence that 85% of the mass in the universe is invisible dark matter.

The team, led by Dr Nobuhiro Okabe (Academia Sinica) and Dr Graham Smith (Birmingham), used the Subaru telescope in Hawaii to investigate the nature of dark matter by measuring its density in fifty galaxy clusters, the most massive objects in the Universe.

"A galaxy cluster is like a huge city that you view from above during the night', explains Smith. 'Each bright city light is a galaxy, and the dark areas between the lights that appears to be empty during the night are actually full of dark matter. You can think of the dark matter in a galaxy cluster as being the infrastructure within which the galaxies live. We wanted to know how the density of dark matter changes as you drive from the centre of a these huge cities out to the suburbs."

More information: 
The research paper on which this release is based was published online in the May 17, 2013 edition of the Astrophysical Journal Letters: N. Okabe et al., "LoCuSS: The Mass Density Profile of Massive Galaxy Clusters at z=0.2", Volume 769, Number 2, Article ID. 35 (2013). iopscience.iop.org/2041-8205/769/2/L35/

Subaru Optics Image: Spiral structure of disk may reveal planets

An image of the disk around SAO 206462 captured with Subaru's  HiCIAO. A coronagraph blocks the direct light of the central star, which appears as the black, circular area in the image. Arrows show the two arms of the spiral structure around the star. Credit: NAOJ 

An international team of astronomers has used HiCIAO (High Contrast Instrument for the Subaru Next Generation Optics) to observe a disk around the young star SAO 206462.

They succeeded in capturing clear, detailed images of its disk, which they discovered has a spiral structure with two discernable arms.

On the basis of their observations and modeling according to spiral density wave theory, the team suspects that dynamic processes, possibly resulting from planets in the disk, may be responsible for its spiral shape.

This research may provide the basis for another indirect method of detecting planets. Scientists have known that planets form in a broad disk of dust and gas surrounding a star, a so-called "protoplanetary disk."

However, the composition of these special disks as well as the process by which they give rise to planets have remained a mystery.

The bright light of a central star makes it difficult to detect fainter objects around it or to capture a detailed image of the composition of the disk itself.

Recent research with HiCIAO, Subaru Telecope's "planet-hunter", has overcome some of those obstacles.

By masking the bright light from the central star, the instrument can then detect more detailed features of the star's disk and the objects that it contains. 

Subaru Telescope Confirms Signs of Unseen Planets in Dust Ring of HR 4796 A

Near-infrared (1.6 micron) image of the debris ring around the star HR 4796 A.

An astronomical unit (AU) is a unit of length that corresponds to the average distance between the Earth and Sun, almost 92 million miles (over 149 million km).

The ring consists of dust grains in a wide orbit (roughly twice the size of Pluto's orbit) around the central star.

Its edge is so precisely revealed that the researchers could confirm a previously suspected offset between the ring's center and the star's location.

This "wobble" in the dust's orbit is most likely caused by the unbalancing action of, so far undetected, massive planets likely to be orbiting within the ring.

Furthermore, the image of the ring appears to be smudged out at its tips and reveals the presence of finer dust extending out beyond the main body of the ring.

The SEEDS (Strategic Exploration of Exoplanets and Disks with Subaru Telescope/HiCIAO) project, a five-year international collaboration launched in 2009 and led by Motohide Tamura of NAOJ (National Astronomical Observatory of Japan) has yielded another impressive image that contributes to our understanding of the link between disks and planet formation.

Researchers used Subaru's planet-finder camera, HiCIAO (High Contrast Instrument for the Subaru Next Generation Adaptive Optics), to take a crisp high-contrast image of the dust ring around HR 4796 A, a young (8-10 million years old) nearby star, only 240 light years away from Earth.

The ring consists of dust grains in a wide orbit, roughly twice the size of Pluto's orbit, around the central star.

The resolution of the image of the inner edge of the ring is so precise that an offset between its center and the star's position can be measured.

Although data from the Hubble Space Telescope led another research group to suspect such an offset, the Subaru data not only confirm its presence but also reveal it to be larger than previously assumed.

Formation of Scheila's Triple Dust Tails Explained

Optical images of Scheila at three different epochs with different telescopes.

Images of the triple dust tails were taken on the 12th and 19th of December 2010 using the Murikabushi Telescope. 

Bottom: Suprime-Cam on the Subaru Telescope captured this image of the linear structure on the 2nd of March 2011.

A research team of planetary scientists and astronomers, mainly from Seoul National University, the National Astronomical Observatory of Japan (NAOJ), the Institute of Space and Astronautical Science (ISAS), and Kobe University, has explained the formation of peculiar triple dust tails from the asteroid Scheila (asteroid #596).

The researchers concluded that another asteroid about 20-50 meters in size impacted Scheila from behind on December 3, 2010, and accounted for its unusual brightness and form.

On December 11.4, 2010, Steve Larson of the Catalina Sky Survey noticed an odd brightness from Scheila, an asteroid on the outer region of the main belt of asteroids that orbit in an area between Mars and Jupiter.

Three streams of dust appeared to trail from the asteroid. Data from NASA's Swift Satellite and the Hubble Space Telescope suggested that a smaller asteroid's impact was the likely trigger for the appearance of comet-like tails from Scheila.

However, questions remained about the date when the dust emission occurred and how the triple dust tails formed. The current research team sought answers to these queries.

Soon after reports of Scheila's unusual brightness, the current research team used the Subaru Prime Focus Camera (Suprime-Cam) on the Subaru Telescope (8.2 m), the Ishigakijima Astronomical Observatory Murikabushi Telescope (1.05 m), and the University of Hawaii 2.2 m Telescope to make optical observations of these mysterious dust tails over a three-month period.

The top of Figure 1 shows images of the development of the dust tails taken by the Murikabushi Telescope on the 12th and 19th of December 2010. Although asteroids generally look like points when observed from Earth, Scheila looked like a comet.

As the three streaks of dust streamed from the asteroid, their surface brightness decreased. Eventually the dust clouds became undetectable, and then a faint linear structure appeared.

The bottom of Figure 1 shows the image obtained by Subaru Telescope on March 2, 2011. Based on these images of the linear structure, the scientists determined a dust emission date of December 3.5+/-1, 2010. Steve Larson of the Catalina Sky Survey noticed that Scheila had a slightly diffuse appearance on December 3.4, 2010.

Therefore, it is likely that the collision of the asteroids occurred within the short time between December 2 12:00 UT and December 3 10:00 UT.

To explain the formation of Scheila's triple dust tails, the research team conducted a computer simulation of Scheila's dust emission on December 3th.

Their simulation was based on information gained through impact experiments in a laboratory at ISAS, a hypervelocity impact facility and division of the Japan Aerospace Exploration Agency (JAXA). Figure 2 shows the ejecta produced by an oblique impact, which was not a head-on collision.

Two prominent features characterize oblique impacts and the shock waves generated by them. One feature, a downrange plume, occurs in a direction downrange from the impact site and results from the fragmentation or sometimes evaporation of the object that impacted another.

A second feature occurs during the physical destruction of the impacted object; a shock wave spreads from the impact site, scoops out materials (conical impact ejecta), and forms an impact crater. The axis of the cone of ejecta is roughly perpendicular to the surface at the impact site.

The team reasoned that these two processes caused the ejection of Scheila's dust particles and that sunlight pushed them away from the asteroid. After performing a tremendous number of computer simulations under different conditions, they could only duplicate their observed images when an object struck Scheila's surface from behind (Figures 3 and 4).

Taking all of the evidence into account-their observations and simulations--the research team concluded that there is only one way to explain the mysterious brightness and triple tails of dust from Scheila. A smaller asteroid obliquely impacted Scheila from behind.

Brown Drawf: Rogue Failed Star Is One of Smallest Ever Seen

Extreme brightness changes observed on a nearby tiny brown dwarf star may indicate a storm grander than any yet seen on an alien world, scientists say.

CREDIT: Jon Lomberg

Astronomers have discovered more than two dozen previously unknown failed stars, including one that ranks among the puniest of its kind, new research finds.

The newfound objects are brown dwarfs, strange bodies that are larger than planets but too small to trigger the internal nuclear fusion reactions required to become full-fledged stars.

Astronomers discovered the objects in two young star clusters using Japan's Subaru Telescope in Hawaii and the Very Large Telescope in Chile.

One of the brown dwarfs is just six times the mass of Jupiter, making it "one of the puniest free-floating objects known," researchers said in a statement.

Subaru Telescope Detects Most Distant and Ancient Supernovae in the Young Universe

A team of Japanese, Israeli, and U.S. astronomers used the Subaru Telescope to assemble the largest sample ever found of the most distant exploding stars called supernovae, which emitted their light about ten billion years ago, long before the Earth was formed.

The researchers used this sample of ancient supernovae to determine how frequently such explosions of stars occurred in the young universe.

Supernovae have substantial importance in astrophysics. They are nature's element factories: essentially all of the elements in the periodic table that are heavier than oxygen were formed through nuclear reactions immediately preceding and during these colossal explosions.

The explosions fling these elements into interstellar space, where they serve as raw materials for new generations of stars and planets.

Thus, the atoms in our bodies, like the calcium atoms in our bones or the iron atoms in our blood, were created in supernovae.

By tracking the frequency and types of supernova explosions back through cosmic time, astronomers can reconstruct the universe's history of element creation, from the plain mix of hydrogen and helium that existed for the first billion years or so after the Big Bang, up to the elemental richness we see today.

However, looking back in time requires looking out to great distances, which means that even these bright explosions are exceedingly faint and difficult to spot.

To overcome this obstacle, the team took advantage of a combination of the Subaru Telescope's assets: the huge light-collecting power of its large 8.2 meter primary mirror; the sharpness of its images, and the wide field of view of its prime focus camera (Suprime-Cam).

On four separate occasions, they pointed the telescope toward one single field called the Subaru Deep Field, which spans an area of the sky similar to that covered by the full moon and had previously been studied in great detail by Subaru scientists.

By "staring" with the telescope at this single field, they let the faint light from the most distant galaxies and supernovae accumulate over several nights at a time, thus forming a very long and deep exposure of the field.

Read more at the Subaru Telescope portal

NASA Chandra Image: Pandora’s Cluster — Clash of the Titans

A team of scientists studying the galaxy cluster Abell 2744, nicknamed Pandora’s Cluster, have pieced together the cluster’s complex and violent history.

They did this using space and ground based telescopes, including the Hubble Space Telescope, the European Southern Observatory’s Very Large Telescope, the Japanese Subaru telescope, and NASA’s Chandra X-ray Observatory.

The giant galaxy cluster appears to be the result of a simultaneous pile-up of at least four separate, smaller galaxy clusters.

The crash took place over a span of 350 million years.

The galaxies in the cluster make up less than 5 percent of its mass. The gas (around 20 percent) is so hot that it shines only in X-rays (colored red in this image). The distribution of invisible dark matter (making up around 75 percent of the cluster’s mass) is colored here in blue.

Dark matter does not emit, absorb, or reflect light, but it makes itself apparent through its gravitational attraction. To pinpoint the location of this elusive substance the team exploited a phenomenon known as gravitational lensing. This is the bending of light rays from distant galaxies as they pass through the gravitational field created by the cluster.

The result is a series of telltale distortions in the images of galaxies in the background of the Hubble and VLT observations. By carefully analyzing the way that these images are distorted, it is possible to accurately map where the dark matter lies.


Chandra mapped the distribution of hot gas in the cluster.
The data suggest that the complex collision has separated out some of the hot gas (which interacts upon collision) and the dark matter (which does not) so that they now lie apart from each other, and from the visible galaxies.

Near the core of the cluster there is a “bullet” shape where the gas of one cluster collided with that of another to create a shock wave. The dark matter passed through the collision unaffected.

In another part of the cluster, galaxies and dark matter can be found, but no hot gas. The gas may have been stripped away during the collision, leaving behind no more than a faint trail.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center manages the telescope.

The Space Telescope Science Institute (STScI) conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

Subaru Telescope Spots Tiny Companion Planet To Sun-Like Star

This August 2009 discovery image of GJ 758 B was taken with the Subaru Telescope's HiCIAO instrument in the near infrared, which measures and records differences in heat.


Without the special technique employed here (angular differential imaging), the star's glare would overwhelm the light from the planet candidates.


The planet-like object, GJ 758 B, is circled as B in the lower right portion of the image. An unconfirmed companion planet or planet-like object, C, can be viewed above B.


The star, GJ 758, is located at the center of the image, at the hub of the starburst. The graphic at the top compares the orbital distances of solar system planets. Credit: Max Planck Institute for Astronomy/National Astronomical Observatory of Japan