Astronomers pin down origins of 'mile markers' for expansion and acceleration of universe

Nov. 19, 2012 — A study using a unique new instrument on the world's largest optical telescope has revealed the likely origins of especially bright supernovae that astronomers use as easy-to-spot "mile markers" to measure the expansion and acceleration of the universe.

In a paper to appear in the Astrophysical Journal, researchers describe observations of recent supernova 2011fe that they captured with the Large Binocular Telescope (LBT) using a tool created at Ohio State University: the Multi-Object Double Spectrograph (MODS).

MODS measures the frequencies and intensities of light shining from a star. Stars shine at different frequencies depending on the chemical elements they are made of; a star like the sun, which is made mostly of hydrogen, shines at different frequencies than a star that is made mostly of helium. So astronomers can use spectra to determine what a particular star is made of.

Based on the frequencies of light emanating from supernova 2011fe, this type of supernova -- known as Type Ia -- is most likely caused by the interaction between a pair of dead stars known as white dwarfs, the astronomers concluded. One white dwarf orbits the other and sheds material onto it, until the other white dwarf becomes unstable and explodes, shining billions of times brighter than the sun.

Astronomers worldwide have tried to confirm the origin of Type Ia supernovae for decades. Groups have proposed several different hypotheses, including exotic scenarios involving white dwarfs paired with still-"living" giant stars, or even stars like the sun.

Kris Stanek, professor of astronomy at Ohio State and a co-author of the study, explained why settling this issue is important.

"We really want to know more about these supernovae, given their importance in our understanding of how the universe is expanding," he said. "Many observations have been done over the years, and I think many astronomers are starting to accept one explanation -- that two white dwarfs are probably responsible."

Still, the alternative theories keep re-emerging, he said: "like zombies that won't die."

"With this study, we were looking for a zombie 'kill shot,' and we think we found it."

Rick Pogge, professor of astronomy and lead designer of MODS, said that the spectrograph is the ideal tool for settling the debate.

"MODS is one of the most sensitive optical spectrometers in operation today, and being used on what is currently the world's largest optical telescope. If we couldn't kill this debate with MODS and the LBT, something would be dreadfully wrong," he added.

Type Ia supernovae make good mile markers for the universe because their extreme brightness -- 5 billion times brighter than the sun -- makes them easy to see, and their distinctive pattern of brightening and dimming in the weeks after they appear makes them easily identifiable.

Astronomers use that information to calculate the distance from Earth to the supernova, and in turn, calculate how fast the universe is expanding. Knowing more about the composition of the stars that create the supernovae could open up new ideas in the understanding of that expansion.

Here's what nearly all astronomers agree on: Type Ia supernovae originate in binary systems, where one star or star-like object is orbiting another. The main object -- the one that initiates the explosion -- is a white dwarf, the massive remnants of a dead star. Over time, the white dwarf's gravity peels off gas and dust from the companion and absorbs that material. Eventually, the white dwarf becomes unstable, and explodes in a supernova.

At issue, explained lead study author and doctoral student Ben Shappee, is the identity of the white dwarf's companion -- is it another white dwarf, or a giant star, or even a star like our sun?

The Ohio State astronomers found their answer in the light spectrum emanating from the supernova. If the companion were a star like ours, or even a giant star, a sizeable portion of the debris blown away from the supernova would contain atoms of the element hydrogen.

Supernova 2011fe provided a good chance for the researchers to test for the presence of hydrogen. Located in the Pinwheel Galaxy some 21 million light-years away, it was the closest near-Earth Type Ia supernova to occur in the last 20 years.

"If the companion were a star such as ours or even a red giant, we would expect to see a lot of hydrogen in the signal -- maybe even half a solar mass' worth, as the companion was blown away. But instead, we saw at most only one tenth of one percent of a solar mass' worth of hydrogen. That suggests that the white dwarf's companion had very little if any hydrogen in it, and is likely another white dwarf," Shappee said.

Pogge called the study "a beautiful demonstration of the kind of data we are able to get on a routine basis with the LBT and MODS. Our entire instrument team is very proud of how well MODS is working."

In fact, this study was done with only one half of the MODS system -- MODS1 -- which is currently installed on one mirror of the LBT. It's twin, MODS2, is currently under construction in Columbus and scheduled to be installed on the second mirror in early 2013.

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by Ohio State University. The original article was written by Pam Frost Gorder.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Benjamin J. Shappee, K. Z. Stanek, R. W. Pogge, P. M. Garnavich. No Stripped Hydrogen in the Nebular Spectra of Nearby Type Ia Supernova 2011fe. Astrophysical Journal, 2012 [link]

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Dark energy is real, say astronomers

Sep. 11, 2012 — Dark energy, a mysterious substance thought to be speeding up the expansion of the Universe is really there, according to a team of astronomers at the University of Portsmouth and LMU University Munich.

After a two-year study led by Tommaso Giannantonio and Robert Crittenden, scientists conclude that the likelihood of its existence stands at 99.996 per cent. Their findings are published in the Monthly Notices of the Royal Astronomical Society.

Professor Bob Nichol, a member of the Portsmouth team, said: "Dark energy is one of the great scientific mysteries of our time, so it isn't surprising that so many researchers question its existence.

"But with our new work we're more confident than ever that this exotic component of the Universe is real -- even if we still have no idea what it consists of."

Over a decade ago, astronomers observing the brightness of distant supernovae realised that the expansion of the Universe appeared to be accelerating. The acceleration is attributed to the repulsive force associated with dark energy now thought to make up 73 per cent of the content of the cosmos. The researchers who made this discovery received the Nobel Prize for Physics in 2011, but the existence of dark energy remains a topic of hot debate.

Many other techniques have been used to confirm the reality of dark energy but they are either indirect probes of the accelerating Universe or susceptible to their own uncertainties. Clear evidence for dark energy comes from the Integrated Sachs Wolfe effect named after Rainer Sachs and Arthur Wolfe.

The Cosmic Microwave Background, the radiation of the residual heat of the Big Bang, is seen all over the sky. In 1967 Sachs and Wolfe proposed that light from this radiation would become slightly bluer as it passed through the gravitational fields of lumps of matter, an effect known as gravitational redshift.

In 1996, Robert Crittenden and Neil Turok, now at the Perimeter Institute in Canada, took this idea to the next level, suggesting that astronomers could look for these small changes in the energy of the light, or photons, by comparing the temperature of the radiation with maps of galaxies in the local Universe.

In the absence of dark energy, or a large curvature in the Universe, there would be no correspondence between these two maps (the distant cosmic microwave background and relatively closer distribution of galaxies), but the existence of dark energy would lead to the strange, counter-intuitive effect where the cosmic microwave background photons would gain energy as they travelled through large lumps of mass.

The Integrated Sachs Wolfe effect was first detected in 2003 and was immediately seen as corroborative evidence for dark energy, featuring in the 'Discovery of the year' in Science magazine. But the signal is weak as the expected correlation between maps is small and so some scientists suggested it was caused by other sources such as the dust in our galaxy. Since the first Integrated Sachs Wolfe papers, several astronomers have questioned the original detections of the effect and thus called some of the strongest evidence yet for dark energy into question.

In the new paper, the product of nearly two years of work, the team have re-examined all the arguments against the Integrated Sachs Wolfe detection as well as improving the maps used in the original work. In their painstaking analysis, they conclude that there is a 99.996 per cent chance that dark energy is responsible for the hotter parts of the cosmic microwave background maps (or the same level of significance as the recent discovery of the Higgs boson).

"This work also tells us about possible modifications to Einstein's theory of General Relativity," notes Tommaso Giannantonio, lead author of the present study.

"The next generation of cosmic microwave background and galaxy surveys should provide the definitive measurement, either confirming general relativity, including dark energy, or even more intriguingly, demanding a completely new understanding of how gravity works."

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by Royal Astronomical Society (RAS).

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

T. Ginnantonio, R. Crittenden, R. Nichol, A. Ross. The significance of the integrated Sachs-Wolfe effect revisited. Monthly Notices of the Royal Astronomical Society, 2012; (in press) [link]

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Even brown dwarfs may grow rocky planets: Sizing up grains of cosmic dust around failed star

Nov. 30, 2012 — Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have for the first time found that the outer region of a dusty disc encircling a brown dwarf contains millimetre-sized solid grains like those found in denser discs around newborn stars. The surprising finding challenges theories of how rocky, Earth-scale planets form, and suggests that rocky planets may be even more common in the Universe than expected.

Rocky planets are thought to form through the random collision and sticking together of what are initially microscopic particles in the disc of material around a star. These tiny grains, known as cosmic dust, are similar to very fine soot or sand. However, in the outer regions around a brown dwarf -- a star-like object, but one too small to shine brightly like a star -- astronomers expected that grains could not grow because the discs were too sparse, and particles would be moving too fast to stick together after colliding. Also, prevailing theories say that any grains that manage to form should move quickly towards the central brown dwarf, disappearing from the outer parts of the disc where they could be detected.

"We were completely surprised to find millimetre-sized grains in this thin little disc," said Luca Ricci of the California Institute of Technology, USA, who led a team of astronomers based in the United States, Europe and Chile. "Solid grains of that size shouldn't be able to form in the cold outer regions of a disc around a brown dwarf, but it appears that they do. We can't be sure if a whole rocky planet could develop there, or already has, but we're seeing the first steps, so we're going to have to change our assumptions about conditions required for solids to grow," he said.

ALMA's increased resolution compared to previous telescopes also allowed the team to pinpoint carbon monoxide gas around the brown dwarf -- the first time that cold molecular gas has been detected in such a disc. This discovery, and that of the millimetre-size grains, suggest that the disc is much more similar to the ones around young stars than previously expected.

Ricci and his colleagues made their finding using the partially completed ALMA telescope in the high-altitude Chilean desert. ALMA is a growing collection of high precision, dish-shaped antennas that work together as one large telescope to observe the Universe with groundbreaking detail and sensitivity. ALMA "sees" the Universe in millimetre-wavelength light, which is invisible to human eyes. Construction of ALMA is scheduled to finish in 2013, but astronomers began observing with a partial array of ALMA dishes in 2011.

The astronomers pointed ALMA at the young brown dwarf ISO-Oph 102, also known as Rho-Oph 102, in the Rho Ophiuchi star-forming region in the constellation of Ophiuchus (The Serpent Bearer). With about 60 times the mass of Jupiter but only 0.06 times that of the Sun, the brown dwarf has too little mass to ignite the thermonuclear reactions by which ordinary stars shine. However, it emits heat released by its slow gravitational contraction and shines with a reddish colour, albeit much less brightly than a star.

ALMA collected light with wavelengths around a millimetre, emitted by disc material warmed by the brown dwarf. The grains in the disc do not emit much radiation at wavelengths longer than their own size, so a characteristic drop-off in the brightness can be measured at longer wavelengths. ALMA is an ideal instrument for measuring this drop-off and thus for sizing up the grains. The astronomers compared the brightness of the disc at wavelengths of 0.89 mm and 3.2 mm. The drop-off in brightness from 0.89 mm to 3.2 mm was not as steep as expected, showing that at least some of the grains are a millimetre or more in size.

"ALMA is a powerful new tool for solving mysteries of planetary system formation," commented Leonardo Testi from ESO, a member of the research team. "Trying this with previous generation telescopes would have needed almost a month of observing -- impossibly long in practice. But, using just a quarter of ALMA's final complement of antennas, we were able to do it in less than one hour!" he said.

In the near future, the completed ALMA telescope will be powerful enough to make detailed images of the discs around Rho-Oph 102 and other objects. Ricci explained, "We will soon be able to not only detect the presence of small particles in discs, but to map how they are spread across the circumstellar disc and how they interact with the gas that we've also detected in the disc. This will help us better understand how planets come to be."

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by European Southern Observatory - ESO.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

L. Ricci, L. Testi, A. Natta, A. Scholz and I. De Gregorio-Monsalvo. ALMA OBSERVATIONS OF ?-OPH 102: GRAIN GROWTH AND MOLECULAR GAS IN THE DISK AROUND A YOUNG BROWN DWARF. Astrophysical Journal Letters, 2012 (in press)

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

When the first stars blinked on: Very first stars may have turned on when the universe was 750 million years old

Dec. 5, 2012 — As far back in time as astronomers have been able to see, the universe has had some trace of heavy elements, such as carbon and oxygen. These elements, originally churned from the explosion of massive stars, formed the building blocks for planetary bodies, and eventually for life on Earth.

Now researchers at MIT, the California Institute of Technology, and the University of California at San Diego have peered far back in time, to the era of the first stars and galaxies, and found matter with no discernible trace of heavy elements. To make this measurement, the team analyzed light from the most distant known quasar, a galactic nucleus more than 13 billion light-years from Earth.

These quasar observations provide a snapshot of our universe during its infancy, a mere 750 million years after the initial explosion that created the universe. Analysis of the quasar's light spectrum provided no evidence of heavy elements in the surrounding gaseous cloud -- a finding that suggests the quasar dates to an era nearing that of the universe's first stars.

"The first stars will form in different spots in the universe … it's not like they flashed on at the same time," says Robert Simcoe, an associate professor of physics at MIT. "But this is the time that it starts getting interesting."

Simcoe and his colleagues have published the results from their study this week in the journal Nature.

Hitting the universal wall

Based on numerous theoretical models, most scientists agree on a general sequence of events during the universe's early development: Nearly 14 billion years ago, an immense explosion, now known as the Big Bang, threw off massive amounts of matter and energy, creating a rapidly expanding universe. In the minutes following the explosion, protons and neutrons collided in nuclear fusion reactions to form hydrogen and helium.

Eventually, the universe cooled to a point where fusion stopped generating these basic elements, leaving hydrogen as the dominant constituent of the universe. Heavier elements, such as carbon and oxygen, would not form until the first stars appeared.

Astronomers have attempted to identify the point at which the first stars were born by analyzing light from more distant bodies. (The farther away an object is in space, the older it is.) Until now, scientists have only been able to observe objects that are less than about 11 billion years old. These objects all exhibit heavy elements, suggesting stars were already plentiful, or at least well established, at that point in the universe's history.

"[The astrophysics community] sort of hit this wall," says Simcoe, an astrophysicist at MIT's Kavli Institute for Astrophysics and Space Research. "When this [quasar] was discovered, we could sort of leapfrog further back in time and make a measurement that was substantially earlier."

Looking for nothing

The quasar in question, discovered in August 2011, is the most distant of its kind. To study such distant objects, Simcoe and his colleagues built an infrared spectrometer, which they fitted onto the Magellan Telescope, a massive ground-based telescope in Chile. This past January, the team trained the telescope on the newly discovered quasar, and collected data from its light.

The spectrometer split the incoming light into different wavelengths, which the team plotted on a graph. Simcoe then looked for telltale dips in the data, correlating various wavelengths with the light given off by different chemicals.

"Each chemical has its own fingerprint," Simcoe says. "Based on the pattern of what light is absorbed, it tells you the chemical composition."

Simcoe and his colleagues determined the quasar's "intrinsic spectrum" -- the amount of light naturally given off by such a body -- and compared this with the observed data to search for the presence of heavy elements. The group found evidence of hydrogen, but no oxygen, silicon, iron or magnesium in the light data. But confirming the absence of evidence for heavy elements was a challenging task.

"It's always hard to establish the absence of something," Simcoe says.

To do so, the researchers considered every other scenario that might explain the light patterns they observed, including newborn galaxies and other matter situated in front of the quasar. Their efforts ultimately confirmed that the quasar's light spectrum indicated an absence of heavy elements 750 million years after the Big Bang.

"[The birth of the first stars] is one of these important moments in the history of the universe," Simcoe says. "It went from looking like the early universe, which was just gas and dark matter, to looking like it does today, where there are stars and galaxies … it's the point when the universe started to resemble what it looks like today. And it's sort of amazing how early that happens. It didn't take long."

John O'Meara, an associate professor of physics at St. Michael's College in Vermont, says while scientists will have to analyze many more distant quasars to confirm the absence of heavy elements, the MIT group's discovery is an "impressive and important step in advancing our knowledge of the universe when it was very young."

"Prior to this result, we have not seen regions of the universe this old and devoid of heavy elements, so there was a missing link in our understanding of how the elemental content of the universe has evolved with time," O'Meara adds. "[This] discovery possibly provides such a rare environment where the universe had yet to form stars."

Going forward, Simcoe hopes to analyze other quasars from this early era to further confirm the absence of heavy elements.

"If we can find things in this epoch, we can start to characterize them," Simcoe says. "There's always something interesting at the edge."

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by Massachusetts Institute of Technology. The original article was written by Jennifer Chu.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Robert A. Simcoe, Peter W. Sullivan, Kathy L. Cooksey, Melodie M. Kao, Michael S. Matejek, Adam J. Burgasser. Extremely metal-poor gas at a redshift of 7. Nature, 2012; 492 (7427): 79 DOI: 10.1038/nature11612

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Biggest black hole blast discovered: Most powerful quasar outflow ever found

Nov. 26, 2012 — Astronomers using ESO's Very Large Telescope (VLT) have discovered a quasar with the most energetic outflow ever seen, at least five times more powerful than any that have been observed to date. Quasars are extremely bright galactic centres powered by supermassive black holes. Many blast huge amounts of material out into their host galaxies, and these outflows play a key role in the evolution of galaxies. But, until now, observed quasar outflows weren't as powerful as predicted by theorists.

Quasars are the intensely luminous centres of distant galaxies that are powered by huge black holes. This new study has looked at one of these energetic objects -- known as SDSS J1106+1939 -- in great detail, using the X-shooter instrument on ESO's VLT at the Paranal Observatory in Chile [1]. Although black holes are noted for pulling material in, most quasars also accelerate some of the material around them and eject it at high speed.

"We have discovered the most energetic quasar outflow known to date. The rate that energy is carried away by this huge mass of material ejected at high speed from SDSS J1106+1939 is at least equivalent to two million million times the power output of the Sun. This is about 100 times higher than the total power output of the Milky Way galaxy -- it's a real monster of an outflow," says team leader Nahum Arav (Virginia Tech, USA). "This is the first time that a quasar outflow has been measured to have the sort of very high energies that are predicted by theory."

Many theoretical simulations suggest that the impact of these outflows on the galaxies around them may resolve several enigmas in modern cosmology, including how the mass of a galaxy is linked to its central black hole mass, and why there are so few large galaxies in the Universe. However, whether or not quasars were capable of producing outflows powerful enough to produce these phenomena has remained unclear until now [2].

The newly discovered outflow lies about a thousand light-years away from the supermassive black hole at the heart of the quasar SDSS J1106+1939. This outflow is at least five times more powerful than the previous record holder [3]. The team's analysis shows that a mass of approximately 400 times that of the Sun is streaming away from this quasar per year, moving at a speed of 8000 kilometres per second.

"We couldn't have got the high-quality data to make this discovery without the VLT's X-shooter spectrograph," says Benoit Borguet (Virginia Tech, USA), lead author of the new paper. "We were able to explore the region around the quasar in great detail for the first time."

As well as SDSS J1106+1939, the team also observed one other quasar and found that both of these objects have powerful outflows. As these are typical examples of a common, but previously little studied, type of quasars [4], these results should be widely applicable to luminous quasars across the Universe. Borguet and colleagues are currently exploring a dozen more similar quasars to see if this is the case.

"I've been looking for something like this for a decade," says Nahum Arav, "so it's thrilling to finally find one of the monster outflows that have been predicted!"

[1] The team observed SDSS J1106+1939 and J1512+1119 in April 2011 and March 2012 using the X-shooter spectrograph instrument attached to ESO's VLT. By splitting the light up into its component colours and studying in detail the resultant spectrum the astronomers could deduce the velocity and other properties of the material close to the quasar.

[2] The powerful out?ow observed in SDSS J1106+1939 carries enough kinetic energy to play a major role in active galaxy feedback processes, which typically require a mechanical power input of roughly 5% of the luminosity of the quasar. The rate at which kinetic energy is being transferred by the outflow is described as its kinetic luminosity.

[3] SDSS J1106+1939 has an outflow with a kinetic luminosity of at least 1046 ergs s-1. The distances of the outflows from the central quasar (300-8000 light-years) was greater than expected suggesting that we observe the outflows far from the region in which we assume them to initially accelerated (0.03-0.4 light-years).

[4] A class known as Broad Absorption Line (BAL) quasars.

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by European Southern Observatory - ESO.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Benoit C.J. Borguet, Nahum Arav, Doug Edmonds, Carter Chamberlain, Chris Benn. Major contributor to AGN feedback: VLT X-shooter observations of S iv BAL QSO outflows. The Astrophysical Journal, (accepted)

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Hubble sees a galaxy hit a bullseye

Dec. 4, 2012 — In Hubble's image, NGC 922 clearly reveals itself not to be a normal spiral galaxy. The spiral arms are disrupted, a stream of stars extends out towards the top of the image, and a bright ring of nebulae encircles the core. Observing with NASA's Chandra X-ray Observatory reveals more chaos in the form of ultraluminous X-ray sources dotted around the galaxy.

NGC 922's current unusual form is a result of a cosmic bullseye millions of years ago. A smaller galaxy, catalogued as 2MASXI J0224301-244443, plunged right through the heart of NGC 922 and shot out the other side. In wide-field views of the NGC 922, the small interloper can be still be seen shooting away from the scene of the crash.

As the small galaxy passed through the middle of NGC 922, it set up ripples that disrupted the clouds of gas, and triggered the formation of new stars whose radiation then lit up the remaining gas. The bright pink colour of the resulting nebulae is a characteristic sign of this process, and it is caused by excited hydrogen gas (the dominant element in interstellar gas clouds). This process of excitation and emission of light by gases is similar to that in neon signs.

In theory, if two galaxies are aligned just right, with the small one passing through the centre of the larger one, the ring of nebulae should form a perfect circle, but more often the two galaxies are slightly off kilter, leading to a circle that, like this one, is noticeably brighter on one side than the other.

These objects, called collisional ring galaxies, are relatively rare in our cosmic neighbourhood. Although galaxy collisions and mergers are commonplace, the precise alignment and ratio of sizes necessary to form a ring like this is not, and the ring-like phenomenon is also thought to be relatively short-lived.

The chances of seeing one of these galaxies nearby is therefore quite low. Despite the immense number of galaxies in the Universe, this is one of only a handful known in our cosmic neighbourhood. Observations of the more distant Universe (where we see further into the past) show that these rings were more common in the past, however.

Hubble's image of NGC 922 consists of a series of exposures taken in visible light with Hubble's Wide Field Camera 3, and in visible and near-infrared light with the Wide Field and Planetary Camera 2.

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by European Space Agency (ESA).

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Astronomers uncover a surprising trend in galaxy evolution

Oct. 19, 2012 — A comprehensive study of hundreds of galaxies observed by the Keck telescopes in Hawaii and NASA's Hubble Space Telescope has revealed an unexpected pattern of change that extends back 8 billion years, or more than half the age of the universe.

"Astronomers thought disk galaxies in the nearby universe had settled into their present form by about 8 billion years ago, with little additional development since," said Susan Kassin, an astronomer at NASA's Goddard Space Flight Center in Greenbelt, Md., and the study's lead researcher. "The trend we've observed instead shows the opposite, that galaxies were steadily changing over this time period."

Today, star-forming galaxies take the form of orderly disk-shaped systems, such as the Andromeda Galaxy or the Milky Way, where rotation dominates over other internal motions. The most distant blue galaxies in the study tend to be very different, exhibiting disorganized motions in multiple directions. There is a steady shift toward greater organization to the present time as the disorganized motions dissipate and rotation speeds increase. These galaxies are gradually settling into well-behaved disks.

Blue galaxies -- their color indicates stars are forming within them -- show less disorganized motions and ever-faster rotation speeds the closer they are observed to the present. This trend holds true for galaxies of all masses, but the most massive systems always show the highest level of organization.

Researchers say the distant blue galaxies they studied are gradually transforming into rotating disk galaxies like our own Milky Way.

"Previous studies removed galaxies that did not look like the well-ordered rotating disks now common in the universe today," said co-author Benjamin Weiner, an astronomer at the University of Arizona in Tucson. "By neglecting them, these studies examined only those rare galaxies in the distant universe that are well-behaved and concluded that galaxies didn't change."

Rather than limit their sample to certain galaxy types, the researchers instead looked at all galaxies with emission lines bright enough to be used for determining internal motions. Emission lines are the discrete wavelengths of radiation characteristically emitted by the gas within a galaxy. They are revealed when a galaxy's light is separated into its component colors. These emission lines also carry information about the galaxy's internal motions and distance.

The team studied a sample of 544 blue galaxies from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Redshift Survey, a project that employs Hubble and the twin 10-meter telescopes at the W. M. Keck Observatory in Hawaii. Located between 2 billion and 8 billion light-years away, the galaxies have stellar masses ranging from about 0.3 percent to 100 percent of the mass of our home galaxy.

A paper describing these findings will be published Oct. 20 in The Astrophysical Journal.

The Milky Way galaxy must have gone through the same rough-and-tumble evolution as the galaxies in the DEEP2 sample, and gradually settled into its present state as the sun and solar system were being formed.

In the past 8 billion years, the number of mergers between galaxies large and small has decreased sharply. So has the overall rate of star formation and disruptions of supernova explosions associated with star formation. Scientists speculate these factors may play a role in creating the evolutionary trend they observe.

Now that astronomers see this pattern, they can adjust computer simulations of galaxy evolution until these models are able to replicate the observed trend. This will guide scientists to the physical processes most responsible for it.

The DEEP2 survey is led by Lick Observatory at the University of California at Santa Cruz in collaboration with the University of California at Berkeley, the University of Hawaii at Manoa, Johns Hopkins University in Baltimore, Md., the University of Chicago and the California Institute of Technology in Pasadena.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Md., conducts Hubble science operations. STScI is operated by the Association of Universities for Research in Astronomy, Inc. in Washington.

For more information about NASA's Hubble Space Telescope, visit: http://www.nasa.gov/hubble

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by NASA.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Susan A. Kassin, Benjamin J. Weiner, S. M. Faber, Jonathan P. Gardner, C. N. A. Willmer, Alison L. Coil, Michael C. Cooper, Julien Devriendt, Aaron A. Dutton, Puragra Guhathakurta, David C. Koo, A. J. Metevier, Kai G. Noeske, Joel R. Primack. The Epoch of Disk Settling: z ~ 1 to Now. The Astrophysical Journal, 2012; 758 (2): 106 DOI: 10.1088/0004-637X/758/2/106

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Fireworks in the early universe: In star-forming galaxies, energy bursts from massive central black hole accretion

Sep. 19, 2012 — Galaxies in the early universe grew fast by rapidly making new stars. Such prodigious star formation episodes, characterized by the intense radiation of the newborn stars, were often accompanied by fireworks in the form of energy bursts caused by the massive central black hole accretion in these galaxies.

This discovery by a group of astronomers led by Peter Barthel of the Kapteyn Institute of the University of Groningen in the Netherlands is published September 19 in the Astrophysical Journal Letters.

Our Milky Way galaxy forms stars at a slow, steady pace: on average one new star a year is born. Since the Milky Way contains about a hundred billion stars, the actual changes are very slight. The Milky Way is an extremely quiet galaxy; its central black hole is inactive, with only weak energy outbursts due to the occasional capture of a passing star or gas cloud.

Bright, exotic radiation

This is in marked contrast to the 'active' galaxies of which there are various types and which were abundant in the early universe. Quasars and radio galaxies are prime examples: owing to their bright, exotic radiation, these objects can be observed as far as the edge of the observable universe. The light of the normal stars in their galaxies is extremely faint at such distances, but active galaxies can be easily detected through their luminous radio, ultraviolet or X-ray radiation, which results from steady accretion onto their massive central black holes.

Peculiar exotic objects

Until recently these distant active galaxies were only interesting in their own right as peculiar exotic objects. Little was known about the composition of their galaxies, or their relationship to the normal galaxy population. However, in 2009 ESA's Herschel space telescope was launched. Herschel is considerably larger than NASA's Hubble, and operates at far-infrared wavelengths. This enables Herschel to detect heat radiation generated by the processes involved in the formation of stars and planets at a small scale, and of complete galaxies at a large scale.

Initial inspection

Peter Barthel has been involved with Herschel since 1997 and heads an observational programme targeting distant quasars and radio galaxies. His team used the Herschel cameras to observe seventy of these objects. Initial inspection of the observations has revealed that many emit bright far-infrared radiation.

The Astrophysical Journal Letter 'Extreme host galaxy growth in powerful early-epoch radio galaxies', by Peter Barthel and co-authors Martin Haas (Bochum University, GER), Christian Leipski (Max-Planck Institute for Astronomy, Heidelberg, GER) and Belinda Wilkes (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), describes their project and the detailed analysis of the first three distant radio galaxies.

Simultaneous grow

The fact that these three objects, as well as many others from the observational sample, emit strong far-infrared radiation indicates that vigorous star formation is taking place in their galaxies, creating hundreds of stars per year during one or more episodes lasting millions of years. The bright radio emission implies strong, simultaneous black hole accretion. This means that while the black holes in the centres of the galaxies are growing (as a consequence of the accretion), the host galaxies are also growing rapidly.

The Herschel observations thereby provide an explanation for the observation that more massive galaxies have more massive black holes. Astronomers have observed this scaling relationship since the 1990s: the fireworks in the early universe could well be responsible for this relationship.

Barthel: 'It is becoming clear that active galaxies are not only among the largest, most distant, most powerful and most spectacular objects in the universe, but also among the most important objects; many if not all massive normal galaxies must also have gone through similar phases of simultaneous black hole-driven activity and star formation.'

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by University of Groningen.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Peter Barthel, Martin Haas, Christian Leipski, Belinda Wilkes. EXTREME HOST GALAXY GROWTH IN POWERFUL EARLY-EPOCH RADIO GALAXIES. The Astrophysical Journal, 2012; 757 (2): L26 DOI: 10.1088/2041-8205/757/2/L26

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Black holes have properties that resemble dynamics of both solids and liquids

Dec. 11, 2012 — Black holes are surrounded by many mysteries, but now researchers from the Niels Bohr Institute, among others, have come up with new groundbreaking theories that can explain several of their properties. The research shows that black holes have properties that resemble the dynamics of both solids and liquids.

The results are published in the scientific journal, Physical Review Letters.

Black holes are extremely compact objects in the universe. They are so compact that they generate an incredibly strong gravitational pull and everything that comes near them is swallowed up. Not even light can escape, so light that hits a black hole will not be reflected, but will be entirely absorbed, as a result, they cannot be seen and we call them black holes.

"But black holes are not completely black, because we know that they emit radiation and there are indications that the radiation is thermal, i.e. it has a temperature," explains Niels Obers, a professor of theoretical particle physics and cosmology at the Niels Bohr Institute at the University of Copenhagen.

Multiple dimensions

Researchers know that the black holes are very compact, but they do not know what their quantum properties are. Niels Obers works with theoretical modelling to better understand the physics of black holes. He explains that you can look at a black hole like a particle. A particle has in principle no dimensions. It is a point. If you give a particle an extra dimension, it becomes a string. If you give the string an extra dimension, it becomes a plane. Physicists call such a plane a 'brane' (the word 'brane' is related to 'membrane' from the biological world).

"In string theory, you can have different branes, including planes that behave like black holes, which we call black branes. The black branes are thermal, that is to say, they have a temperature and are dynamical objects. When black branes are folded into multiple dimensions, they form a 'blackfold'," explains Niels Obers, who worked out this new way of looking at black branes with associate professor in theoretical physics at the Niels Bohr Institute, Troels Harmark, back in 2009.

New breakthrough

Niels Obers and his two doctoral students Jay Armas and Jakob Gath have now made a new breakthrough in the description of the physics of black holes based on the theories of the black branes and blackfolds,

"The black branes are hydro-dynamic objects, that is to say that they have the properties of a liquid. We have now discovered that black branes also have properties, which can be explained in terms of solids. They can behave like elastic material when we bend them," explains Jay Armas.

He explains that when the black branes are bent and folded into a blackfold, a so-called piezoelectric effect (electricity that occurs due to pressure) is created. This new effect can be understood as a slightly bent and charged black string with a greater concentration of electric charge on the innermost side in relation to the outermost side. This produces two electrically charged poles on the black strings. Black holes are predicted by Einstein's theory of gravity. This means that there is a very surprising relationship between gravity and fluid mechanics and solid-state physics.

"With these new theories, we expect to be able to explain other black hole phenomena, and we expect to be able to better understand the physical properties of neutron stars. We also expect to gain a greater understanding of the so-called particle theories, which are, for example, relevant for understanding the quark-gluon-plasma in the primordial universe," explains Niels Obers.

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by University of Copenhagen.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Jay Armas, Jakob Gath, Niels Obers. Black Branes as Piezoelectrics. Physical Review Letters, 2012; 109 (24) DOI: 10.1103/PhysRevLett.109.241101

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

From super to ultra: Just how big can black holes get?

Dec. 18, 2012 — Some of the biggest black holes in the Universe may actually be even bigger than previously thought, according to a study using data from NASA's Chandra X-ray Observatory.

Astronomers have long known about the class of the largest black holes, which they call "supermassive" black holes. Typically, these black holes have masses ranging between a few million and a few billion times that of our sun.

This new analysis of the brightest galaxies in a sample of 18 galaxy clusters suggests that the masses of at least ten of the supermassive black holes in these galaxies are ultramassive, in that they weigh between 10 and 40 billion times the mass of the sun. Astronomers refer to black holes of this size as "ultramassive" black holes and only know of a few confirmed examples.

"Our results show that there may be many more ultramassive black holes in the universe than previously thought," said study leader Julie Hlavacek-Larrondo of Stanford University and formerly of Cambridge University in the UK.

The researchers estimated the masses of the black holes in the sample by using an established relationship between masses of black holes, and the amount of X-rays and radio waves they generate. This relationship, called the fundamental plane of black hole activity, fits the data on black holes with masses ranging from 10 solar masses to a billion solar masses.

The black hole masses derived by Hlavacek-Larrondo and her colleagues were about ten times larger than those derived from standard relationships between black hole mass and the properties of their host galaxy. One of these relationships involves a correlation between the black hole mass and the infrared luminosity of the central region, or bulge, of the galaxy.

"These results may mean we don't really understand how the very biggest black holes coexist with their host galaxies," said co-author Andrew Fabian of Cambridge University. "It looks like the behavior of these huge black holes has to differ from that of their less massive cousins in an important way."

All of the potential ultramassive black holes found in this study lie in galaxies at the centers of massive galaxy clusters containing huge amounts of hot gas. Outbursts powered by the central black holes are needed to prevent this hot gas from cooling and forming enormous numbers of stars. To power the outbursts, the black holes must swallow large amounts of mass in the form of hot gas. Because the largest black holes can swallow the most mass and power the biggest outbursts, ultramassive black holes had already been predicted to exist to explain some of the most powerful outbursts seen. The extreme environment experienced by these galaxies may explain why the standard relations for estimating black hole masses do not apply.

These results can only be confirmed by making detailed mass estimates of the black holes in this sample, which is by modeling the motion of stars or gas in the vicinity of the black holes. Such a study has been carried out for the black hole in the center of the galaxy M87, the central galaxy in the Virgo Cluster, the nearest galaxy cluster to Earth. The mass of M87's black hole, as estimated from the motion of the stars, is significantly higher than the estimate using infrared data, approximately matching the correction in black hole mass estimated by the authors of the Chandra study.

"Our next step is to measure the mass of these monster black holes in a similar way to M87, and confirm their existence. I wouldn't be surprised if we end up finding the biggest black holes in the Universe," said Hlavacek-Larrondo. "If our results are confirmed, they will have important ramifications for understanding the formation and evolution of black holes across cosmic time."

In addition to the X-rays from Chandra, the new study also uses radio data from the NSF's Karl G. Jansky Very Large Array (JVLA) and the Australia Telescope Compact Array (ATCA) and infrared data from the 2 Micron All-Sky Survey (2MASS).

These results were published in the July 2012 issue of The Monthly Notices of the Royal Astronomical Society.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by Chandra X-ray Observatory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

J. Hlavacek-Larrondo, A. C. Fabian, A. C. Edge, M. T. Hogan. On the hunt for ultramassive black holes in brightest cluster galaxies. Monthly Notices of the Royal Astronomical Society, 2012; 424 (1): 224 DOI: 10.1111/j.1365-2966.2012.21187.x

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

New view of the Sun: Radio telescope could save world billions through advanced warnings

Nov. 30, 2012 — A small pocket of Western Australia's remote outback is set to become the eye on the sky and could potentially save the world billions of dollars. The Murchison Widefield Array (MWA) radio telescope, unveiled November 30, will give the world a dramatically improved view of the Sun and provide early warning to prevent damage to communication satellites, electric power grids and GPS navigation systems.

The $51 million low-frequency radio telescope will be able to detect and monitor massive solar storms, such as the one that cut power to six million people in Canada in 1989 during the last peak in solar activity.

In 2011, experts warned that a major solar storm could result in damage to integral power supplies and communication networks of up to US$2 trillion -- the equivalent of a global Hurricane Katrina.

The MWA will aim to identify the trajectory of solar storms, quadrupling the warning period currently provided by near-Earth satellites. This is timely as the Sun is due to re-enter peak activity in 2013, with a dramatic increase in the number and severity of solar storms expected, with the potential to disrupt global communications and ground commercial airlines.

The completion of the MWA realises eight years of work by an international consortium of 13 institutions across four countries (Australia, USA, India and New Zealand), led by Curtin University.

The Murchison Radio-astronomy Observatory (MRO: operated by CSIRO) was chosen by the consortium because it is the world's best location for low frequency radio astronomy. The site has also been selected as the future home for a major part of the Square Kilometre Array.

"The MWA will keep watch on the Sun during the upcoming period of maximum solar activity. It has the potential to deliver very real and immediate benefits to the entire global population. It is a tremendous achievement and testament to the innovative technologies that have been developed to support this instrument," said Director of the MWA and Professor of Radio Astronomy at Curtin University, Steven Tingay

The MWA is ground-breaking in other ways too -- it will offer scientists an unprecedented view of the entire history of the Universe, to gain a better understanding of how the early Universe formed and the relationship between gravity and dark matter evolved, including how the very first stars and galaxies formed.

"Understanding how the dramatic transformation took place soon after the Big Bang, over 13 billion years ago, is the final frontier for astrophysicists like me. It has taken eight years to get to this point and it is incredibly exciting to have completed construction and to be collecting scientific data from the MWA," Professor Tingay said.

"Preliminary testing, using only a fraction of the MWA's capability, has already achieved results that are on par with the best results ever achieved in the search for the first stars and galaxies.

"We anticipate a 10-fold improvement in performance when the full capabilities of the MWA are pressed into service in early 2013," Professor Tingay told a group of eminent scientists and VIPs who had travelled from all over the world to attend the telescope's unveiling.

This sentiment has been supported by 2011 Nobel Laureate and member of the Murchison Widefield Array Board, Professor Brian Schmidt, who described the telescope as a highly ambitious project:

"With it we will, for the first time, be able to look at the transformation of the Universe from a rather boring environment of hydrogen and helium to the point where the stars, galaxies, and black holes create the vibrant Universe as we know it," Professor Schmidt said.

"This telescope is an exciting and necessary part of the process of discovery and I see it as a step towards, if not the tool for, an important scientific breakthrough."

The Murchison Widefield Array will have four primary areas of scientific investigation; as well as looking back into the time to the early Universe, soon after the Big Bang, and its in-depth study of the Sun -- Earth connection, the data produced by the telescope will also be used to better understand our galaxy and distant galaxies, as well as violent and explosive phenomena in the Universe.

The MWA has been supported by both State and Federal Government funding, with the majority of federal funding administered by Astronomy Australia Limited. The MWA project recognises the Wadjarri Yamatji people as the traditional owners of the site on which the MWA is built and thanks the Wadjarri Yamatji people for their support.

Murchison Widefield Array Facts

Located 370 km north-east of Geraldton (nearly 800 km from Perth) the MWA is situated in the Shire of Murchison, an area of approximately 50,000 square kilometres (19,300 square miles) and has a population of 114 people. The MWA is located at CSIRO's Murchison Radio-astronomy Observatory (MRO).

The Murchison Widefield Array will pick up radio waves that have travelled between 8 minutes (the Sun) and more than 13 billion years (soon after the Big Bang) to reach Earth.

The telescope spans a 3 diameter kilometre area and is entirely static (no moving parts). It uses 2,048 dual-polarisation dipole antennas arranged into a strategic formation of 128 groups (16 dual-polarisation dipoles per group).

Each of these antennas has been constructed from a flat-pack style design and built in-situ at the MRO by a team of undergraduate students from Curtin University, known as the Student Army.

The telescope is considered low-cost, with each antenna costing approximately $3,000. Comparatively a high frequency dish telescope costs in the region of $500,000.

Radio waves collected from the sky are digitised, producing a new image of the sky every few seconds. These are then sent via high speed optical fibre, an early part of the National Broadband Network, to a processing and archiving facility over 700 kilometres away in Perth (the $80m Pawsey HPC Centre for SKA Science).

When operating at full capacity the telescope will produce the equivalent of a 2 hour long HD movie every 10 seconds (approximately 4 GB every 10 seconds).

Technology giants IBM and Cisco, as well as Western Australian based firm Poseidon Scientific Instruments (acquired by Raytheon in July 2012), have worked with the consortium to create highly specialised hardware to process the vast amount of data created by the telescope.

The primary archiving facility will be the $80million Pawsey HPC Centre for SKA Science, which is being built in Perth. Information is also being automatically transferred to MWA partner organisations in Boston in the United States (MIT) and Wellington in New Zealand (Victoria University of Wellington).

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by International Centre for Radio Astronomy Research (ICRAR).

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Quasar may be embedded in unusually dusty galaxy

Oct. 23, 2012 — Hubble astronomers have looked at one of the most distant and brightest quasars in the universe and are surprised by what they did not see: the underlying host galaxy of stars feeding the quasar. The best explanation is that the galaxy is shrouded in so much dust that the stars are completely hidden everywhere. Astronomers believe that the James Webb Space Telescope will reveal the galaxy.

All but the very first galaxies contain some dust -- the early universe was dust-free until the first generation of stars started making dust through nuclear fusion. As these stars aged and burned out, they filled interstellar space with this dust as they lost their atmospheres. The quasar dates back to an early time in the universe's history -- less than one billion years after the big bang -- but was known to contain large amounts of dust from previous sub-millimeter observations. What surprised the researchers is how completely the dust is shrouding starlight within the galaxy -- none of the starlight seems to be leaking out from around the quasar.

Quasars (short for quasi-stellar object) are the brilliant cores of galaxies where infalling material fuels a super-massive black hole. The black hole is so engorged that some of the energy escapes as powerful blasts of radiation from the surrounding disk of accreting material. This light can appear as a jet-like feature. If the beam shines in Earth's direction the "accretion disk" and jet surrounding the super-massive black hole can appear as a quasar that can outshine its surrounding galaxy a hundred or a thousand times.

The team speculates that the black hole is devouring the equivalent mass of a few suns per year. It may have been eating at a more voracious rate earlier to bulk up to an estimated mass of three billion solar masses in just a few hundred million years.

"If you want to hide the stars with dust, you need to make lots of short-lived massive stars earlier on that lose their mass at the end of their lifetime. You need to do this very quickly, so supernovae and other stellar mass-loss channels can fill the environment with dust very quickly," said Rogier Windhorst of Arizona State University (ASU), Tempe, Ariz. "You also have to be forming them throughout the galaxy to spread the dust throughout the galaxy," added Matt Mechtley, also of ASU.

The quasar was first identified in the Sloan Digital Sky Survey (SDSS). Only a handful of these very distant ultra-luminous quasars were found by the SDSS in about one quarter of the whole sky. Follow-up observations at sub-millimeter wavelengths detected significant dust within the galaxy, but did not show how and where dust was distributed, and if or where star-clusters might be visible through the dust. Most nearby galaxies -- even if rather dusty -- still have some regions where stars or star-clusters poke through the dust.

Hubble was used to very carefully subtract light from the quasar image and look for the glow of surrounding stars. The team accomplished this by looking at the glow of a reference star in the sky near the quasar and using it as a template to remove the quasar light from the image. Once the quasar was removed, no significant underlying starlight was detected. The underlying galaxy's stars could have been easily detected, had they been present and relatively unobscured by dust in at least some locations.

"It is remarkable that Hubble didn't find any of the underlying galaxy," said Windhorst. "The underlying galaxy is everywhere much fainter than expected, and therefore must be in a very dusty environment throughout. It's one of the most rip-roaring forest fires in the universe. It's creating so much smoke that you're not seeing any starlight, anywhere. The forest fire is complete, not a tree is spared."

"Because we don't see the stars, we can rule out that the galaxy that hosts this quasar is a normal galaxy," said Mechtley. "It's among the dustiest galaxies in the universe, and the dust is so widely distributed that not even a single clump of stars is peeking through. We're very close to a plausible detection, in the sense that if we had gone a factor of two deeper we might have detected some light from its young stars, even in such a dusty galaxy."

This result was published in the Sept. 10 issue of the Astrophysical Journal Letters in a paper by M. Mechtley, R. Windhorst, and an international team of collaborators.

NASA's planned James Webb Space Telescope will pursue this object. "The Webb telescope is designed to make a definitive detection of this," said Windhorst. We will get solid detections of the stars with Webb's better sensitivity to longer wavelengths of light, which will better probe the dusty regions in these young galaxies.

The Webb telescope will also have the infrared sensitivity to peer all the way back to 200 million years after the big bang. If galaxies started forming stars at this early epoch, Webb is designed and being built to detect them.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Md., conducts Hubble science operations and is the science and mission operations center for the James Webb Space Telescope. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by NASA/Goddard Space Flight Center.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

M. Mechtley, R. A. Windhorst, R. E. Ryan, G. Schneider, S. H. Cohen, R. A. Jansen, X. Fan, N. P. Hathi, W. C. Keel, A. M. Koekemoer, H. Röttgering, E. Scannapieco, D. P. Schneider, M. A. Strauss, H. J. Yan. Near-Infrared Imaging of a z = 6.42 Quasar Host Galaxy With Thehubble Space Telescopewide Field Camera. The Astrophysical Journal, 2012; 756 (2): L38 DOI: 10.1088/2041-8205/756/2/L38

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Farthest ever view of the universe assembled by combining 10 years of NASA Hubble Space Telescope photographs

Sep. 25, 2012 — Like photographers assembling a portfolio of best shots, astronomers have assembled a new, improved portrait of humankind's deepest-ever view of the universe.

Called the eXtreme Deep Field, or XDF, the photo was assembled by combining 10 years of NASA Hubble Space Telescope photographs taken of a patch of sky at the center of the original Hubble Ultra Deep Field. The XDF is a small fraction of the angular diameter of the full Moon.

The Hubble Ultra Deep Field is an image of a small area of space in the constellation Fornax, created using Hubble Space Telescope data from 2003 and 2004. By collecting faint light over many hours of observation, it revealed thousands of galaxies, both nearby and very distant, making it the deepest image of the universe ever taken at that time.

The new full-color XDF image reaches much fainter galaxies, and includes very deep exposures in red light from Hubble's new infrared camera, enabling new studies of the earliest galaxies in the universe. The XDF contains about 5,500 galaxies even within its smaller field of view. The faintest galaxies are one ten-billionth the brightness of what the human eye can see.

Magnificent spiral galaxies similar in shape to our Milky Way and the neighboring Andromeda galaxy appear in this image, as do the large, fuzzy red galaxies where the formation of new stars has ceased. These red galaxies are the remnants of dramatic collisions between galaxies and are in their declining years. Peppered across the field are tiny, faint, more distant galaxies that were like the seedlings from which today's striking galaxies grew. The history of galaxies -- from soon after the first galaxies were born to the great galaxies of today, like our Milky Way -- is laid out in this one remarkable image.

Hubble pointed at a tiny patch of southern sky in repeat visits (made over the past decade) for a total of 50 days, with a total exposure time of 2 million seconds. More than 2,000 images of the same field were taken with Hubble's two premier cameras -- the Advanced Camera for Surveys and the Wide Field Camera 3, which extends Hubble's vision into near-infrared light -- and combined to make the XDF.

"The XDF is the deepest image of the sky ever obtained and reveals the faintest and most distant galaxies ever seen. XDF allows us to explore further back in time than ever before," said Garth Illingworth of the University of California at Santa Cruz, principal investigator of the Hubble Ultra Deep Field 2009 (HUDF09) program.

The universe is 13.7 billion years old, and the XDF reveals galaxies that span back 13.2 billion years in time. Most of the galaxies in the XDF are seen when they were young, small, and growing, often violently as they collided and merged together. The early universe was a time of dramatic birth for galaxies containing brilliant blue stars extraordinarily brighter than our Sun. The light from those past events is just arriving at Earth now, and so the XDF is a "time tunnel into the distant past." The youngest galaxy found in the XDF existed just 450 million years after the universe's birth in the big bang.

Before Hubble was launched in 1990, astronomers could barely see normal galaxies to 7 billion light-years away, about halfway across the universe. Observations with telescopes on the ground were not able to establish how galaxies formed and evolved in the early universe.

Hubble gave astronomers their first view of the actual forms and shapes of galaxies when they were young. This provided compelling, direct visual evidence that the universe is truly changing as it ages. Like watching individual frames of a motion picture, the Hubble deep surveys reveal the emergence of structure in the infant universe and the subsequent dynamic stages of galaxy evolution.

The infrared vision of NASA's planned James Webb Space Telescope (Webb telescope) will be aimed at the XDF. The Webb telescope will find even fainter galaxies that existed when the universe was just a few hundred million years old. Because of the expansion of the universe, light from the distant past is stretched into longer, infrared wavelengths. The Webb telescope's infrared vision is ideally suited to push the XDF even deeper, into a time when the first stars and galaxies formed and filled the early "dark ages" of the universe with light.

The XDF/HUDF09 team members are G. Illingworth (University of California, Santa Cruz), R. Bouwens (Leiden University), M. Carollo (Swiss Federal Institute of Technology, Zurich (ETH)), M. Franx (Leiden University), V. Gonzalez (University of California, Santa Cruz), I. Labbe (Leiden University), D. Magee and P. Oesch (University of California, Santa Cruz), M. Stiavelli (Space Telescope Science Institute), M. Trenti (University of Cambridge), and P. van Dokkum (Yale University).

The public is invited to participate in a "Meet the Hubble eXtreme Deep Field Observing Team" webinar, in which three key astronomers of the XDF observing team will describe how they assembled the landmark image and explain what it tells us about the evolving universe. Participants are invited to send in questions for the panel of experts to discuss. The webinar will be broadcast at 1:00 p.m. (EDT) on Thursday, September 27, 2012. To participate in the webinar, please visit: http://hubblesite.org/go/xdf/ .

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by Space Telescope Science Institute (STScI).

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Split-personality elliptical galaxy holds a hidden spiral

Oct. 22, 2012 — Most big galaxies fit into one of two camps: pinwheel-shaped spiral galaxies and blobby elliptical galaxies. Spirals like the Milky Way are hip and happening places, with plenty of gas and dust to birth new stars. Ellipticals are like cosmic retirement villages, full of aging residents in the form of red giant stars. Now, astronomers have discovered that one well-known elliptical has a split personality. Centaurus A is hiding a gassy spiral in its center.

"No other elliptical galaxy is known to have spiral arms," said lead author Daniel Espada (National Astronomical Observatory of Japan & Harvard-Smithsonian Center for Astrophysics). "Centaurus A may be an old galaxy, but it's still very young at heart."

Centaurus A isn't your typical elliptical to begin with. Its most striking feature is a dark dust lane across its middle -- a sign that it swallowed a spiral galaxy about 300 million years ago.

Centaurus A slurped that galaxy's gases down, forming a disk that we see nearly edge on. From our point of view, any features in that disk have been hidden by the intervening dust.

To tease out the disk's structure, Espada and his colleagues used the sharp vision of the Smithsonian's Submillimeter Array. This radio telescope can see through dust to pick up signals from naturally occurring carbon monoxide gas. By mapping the gas, the team unveiled two distinct spiral arms within the galaxy's core.

These gaseous tendrils have sizes and shapes similar to spiral arms in galaxies like the Milky Way. Also like the Milky Way's spiral arms, they are forming new generations of stars.

"Centaurus A has been given a new lease on life by that past merger," said Espada.

Computer simulations suggest that the spiral features might endure for hundreds of millions of years to come.

Although Centaurus A is the first elliptical galaxy found to have spiral arms, it may not be the last. Since it's only 12 million light-years away, it's relatively nearby and easy to study. The Atacama Large Millimeter/submillimeter Array (ALMA) potentially can find more split-personality galaxies with its improved radio "vision."

"We definitely will use ALMA to search for other objects that are similar to Centaurus A," added Espada.

These findings were published in The Astrophysical Journal Letters.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by Harvard-Smithsonian Center for Astrophysics.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

D. Espada, S. Matsushita, A. B. Peck, C. Henkel, F. Israel, D. Iono. Disentangling the Circumnuclear Environs of Centaurus A: Gaseous Spiral Arms in a Giant Elliptical Galaxy. The Astrophysical Journal, 2012; 756 (1): L10 DOI: 10.1088/2041-8205/756/1/L10

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

World’s most powerful digital camera opens eye, records first images in hunt for dark energy

Sep. 17, 2012 — Eight billion years ago, rays of light from distant galaxies began their long journey to Earth. That ancient starlight has now found its way to a mountaintop in Chile, where the newly-constructed Dark Energy Camera, the most powerful sky-mapping machine ever created, has captured and recorded it for the first time.

That light may hold within it the answer to one of the biggest mysteries in physics -- why the expansion of the universe is speeding up.

Scientists in the international Dark Energy Survey collaboration announced this week that the Dark Energy Camera, the product of eight years of planning and construction by scientists, engineers, and technicians on three continents, has achieved first light. The first pictures of the southern sky were taken by the 570-megapixel camera on Sept. 12.

"The achievement of first light through the Dark Energy Camera begins a significant new era in our exploration of the cosmic frontier," said James Siegrist, associate director of science for high energy physics with the U.S. Department of Energy. "The results of this survey will bring us closer to understanding the mystery of dark energy, and what it means for the universe."

The Dark Energy Camera was constructed at the U.S. Department of Energy's (DOE) Fermi National Accelerator Laboratory in Batavia, Illinois, and mounted on the Victor M. Blanco telescope at the National Science Foundation's Cerro Tololo Inter-American Observatory (CTIO) in Chile, which is the southern branch of the U.S. National Optical Astronomy Observatory (NOAO). With this device, roughly the size of a phone booth, astronomers and physicists will probe the mystery of dark energy, the force they believe is causing the universe to expand faster and faster.

"The Dark Energy Survey will help us understand why the expansion of the universe is accelerating, rather than slowing due to gravity," said Brenna Flaugher, project manager and scientist at Fermilab. "It is extremely satisfying to see the efforts of all the people involved in this project finally come together."

The Dark Energy Camera is the most powerful survey instrument of its kind, able to see light from over 100,000 galaxies up to 8 billion light years away in each snapshot. The camera's array of 62 charged-coupled devices has an unprecedented sensitivity to very red light, and along with the Blanco telescope's large light-gathering mirror (which spans 13 feet across), will allow scientists from around the world to pursue investigations ranging from studies of asteroids in our own Solar System to the understanding of the origins and the fate of the universe.

"We're very excited to bring the Dark Energy Camera online and make it available for the astronomical community through NOAO's open access telescope allocation," said Chris Smith, director of the Cerro-Tololo Inter-American Observatory. "With it, we provide astronomers from all over the world a powerful new tool to explore the outstanding questions of our time, perhaps the most pressing of which is the nature of dark energy."

Scientists in the Dark Energy Survey collaboration will use the new camera to carry out the largest galaxy survey ever undertaken, and will use that data to carry out four probes of dark energy, studying galaxy clusters, supernovae, the large-scale clumping of galaxies and weak gravitational lensing. This will be the first time all four of these methods will be possible in a single experiment.

The Dark Energy Survey is expected to begin in December, after the camera is fully tested, and will take advantage of the excellent atmospheric conditions in the Chilean Andes to deliver pictures with the sharpest resolution seen in such a wide-field astronomy survey. In just its first few nights of testing, the camera has already delivered images with excellent and nearly uniform spatial resolution.

Over five years, the survey will create detailed color images of one-eighth of the sky, or 5,000 square degrees, to discover and measure 300 million galaxies, 100,000 galaxy clusters and 4,000 supernovae.

The Dark Energy Survey is supported by funding from the U.S. Department of Energy; the National Science Foundation; funding agencies in the United Kingdom, Spain, Brazil, Germany and Switzerland; and the participating DES institutions.

More information about the Dark Energy Survey, including the list of participating institutions, is available at the project website: www.darkenergysurvey.org.

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by DOE/Fermi National Accelerator Laboratory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

BOSS quasars unveil a new era in the expansion history of the universe

Nov. 12, 2012 — BOSS, the Baryon Oscillation Spectroscopic Survey, is mapping a huge volume of space to measure the role of dark energy in the evolution of the universe. BOSS is the largest program of the third Sloan Digital Sky Survey (SDSS-III) and has just announced the first major result of a new mapping technique, based on the spectra of over 48,000 quasars with redshifts up to 3.5, meaning that light left these active galaxies up to 11.5 billion years in the past.

"No technique for dark energy research has been able to probe this ancient era before, a time when matter was still dense enough for gravity to slow the expansion of the universe, and the influence of dark energy hadn't yet been felt," says BOSS principal investigator David Schlegel, an astrophysicist in the Physics Division of the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab). "In our own time, expansion is accelerating because the universe is dominated by dark energy. How dark energy effected the transition from deceleration to acceleration is one of the most challenging questions in cosmology."

Two ways to measure the expanding universe

As an international collaboration, many of whose leading scientists are present or former members of Berkeley Lab, BOSS studies dark energy by mapping baryon acoustic oscillations (BAO) -- the large-scale network of variations in the distribution of visible galaxies and hard-to-see clouds of intergalactic gas, which also reveal impossible-to-see dark matter. The regular spacing of peaks in matter density originated in primordial density variations, whose remnants are visible in the cosmic microwave background radiation. This spacing provides a cosmic ruler for calibrating the rate of expansion wherever BAO can be measured.

Using the Sloan Foundation Telescope at the Apache Point Observatory in New Mexico, BOSS has mounted a two-pronged spectroscopic investigation of BAO. The first priority is to survey normal bright galaxies with redshifts up to 0.8, some seven billion years in the past; first results of the galaxy survey, which included over 300,000 galaxies, were announced in March, 2012. But collecting enough galaxies at redshifts high enough to map BAO in the very early universe can't be done with a 2.5-meter telescope. Thus BOSS's second target: quasars.

"Quasars are the brightest objects in the sky, and therefore the only credible way to measure spectra out to redshift 2.0 and beyond," says Schlegel. "At these redshifts there are a hundred times more galaxies than quasars, but they're too faint to use for BAO."

Quasars are too sparse to measure BAO directly, but there's another way they reveal BAO at high redshifts. As the light of a quasar passes through clouds of intergalactic gas on its way to Earth, its spectrum develops a plethora of hydrogen absorption lines known as a Lyman-alpha forest. Ideally, each absorption line in the "forest" reveals where the quasar's light has passed through an intervening gas cloud. Like a single flashlight seen through the fog, the different prominences and redshifts of the individual absorption lines in a single quasar's spectrum reveal how the gas density varies with distance along the line of sight.

With enough quasars, close enough together and covering a wide expanse of sky, the distribution of intervening gas clouds can be mapped in three dimensions. The idea was first advanced in the early 2000s by Patrick McDonald, then at the Canadian Institute for Theoretical Astrophysics, and Martin White, both now at Berkeley Lab.

"When I presented this idea to a conference of cosmologists in 2003, they thought it was crazy," says White, who is also a professor of physics and astronomy at the University of California at Berkeley and the chair of the BOSS science survey teams. "Nine years later, BOSS has shown that it's an amazingly powerful technique. It has succeeded beyond our wildest dreams."

SDSS-III's far more sophisticated spectrograph, whose construction was directed by Berkeley Lab's Natalie Roe, allows much better coverage and resolution than earlier surveys, but searching for BAO in the Lyman-alpha forest was still a high-risk proposition for many reasons. Lyman-alpha absorption lines occur in the ultraviolet part of the spectrum, which is absorbed by Earth's atmosphere; from the ground, only those quasars whose spectra are redshifted the right amount are useful. The lines tag only neutral hydrogen; most hydrogen in the universe is ionized. Among other uncertainties, irregular heating of hydrogen clouds, or too many quasars too close together, could distort the clustering signal.

"Compared to a galaxy survey, looking for BAO in the Lyman-alpha forest is cool -- high-risk, but high-reward," says Berkeley Lab's Nicholas Ross, who led the target selection team. To catch enough quasar spectra to map clustering -- a minimum of 15 to 20 quasars per square degree of the sky -- BOSS would have to devote 10 percent of the two million individual targets during its five-year run to possible quasars. The targets had to be chosen from photometric data (an object's brightness in different colors), but only after the spectra were taken would the team be sure which targets were real quasars and which were stars or some other quasar mimic. BOSS took the chance.

"We had one thing in our favor," Ross says. "It didn't matter what type of quasar it was, as long as it was high redshift. To identify them we could use ultraviolet data, near-infrared data -- any method, any trick -- because we were only going to use them as backlights to probe the intervening clouds of gas. Ultimately we found that all our selection algorithms worked well."

Searching for the signal

The initial Lyman-alpha result -- the first map of BAO at this very early stage of the universe's evolution -- is based on just a third of the volume of space that BOSS will ultimately map, and includes 60,369 quasars confirmed by visual inspection of their spectra. But to simplify the search for BAO, many of these were discarded.

"To get BAO out of the data, we have to remove artifacts that distort the signal we're looking for," says Berkeley Lab's Bill Carithers. One class of rejects is broad-absorption line quasars, whose spectra have been smeared out by extremely fast-moving gas from the quasar's active center. Another class are quasars whose spectra have "damped Lyman-alpha troughs," which happens, Carithers says, "when the light from the quasar runs into a very, very large clump of gas, so large it wipes out the forest."

With unhelpful spectra removed, BOSS was left with 48,129 quasars. In May of 2011, a team led by Anže Slosar of Brookhaven National Laboratory, formerly at Berkeley Lab, had demonstrated the practicality of measuring the varying density of intergalactic hydrogen gas at cosmological distances using just 14,000 BOSS quasars -- enough, said Slosar, "to establish a proof of the concept."

"We don't use the specific information in a single line of sight, we look at the correlations among many," says Carithers. "BOSS is the first to do this because we have enough quasars -- with too few, you can't see the pattern."

In addition to helping convert the raw data from the telescope into useful scientific information, Berkeley Lab's Stephen Bailey was in charge of generating simulated data sets -- called "mocks" -- to make sure the analysis was dependable.

"Mocks are important when you're trying to measure something that's never been measured before," says Bailey. "We know where the real quasars are and we know what the physics of the gas is, but we don't know where the gas is. Our simulations were based on the positions and redshifts of the real quasars, but with mock spectra that gave different gas distributions. If we could see the simulated distribution in one analysis, we should see it in all."

In the end, after data processing and generation of mock spectra on the Riemann Linux cluster of computers provided by Berkeley Lab's High-Performance Computing Services Group, the competing analyses of the Lyman-alpha forest of over 48,000 quasars all gave similar results.

The analytic techniques used in this report were developed by Andreu Font-Ribera and his collaborators among BOSS's French Participation Group. Applied to the real quasar spectra, they produced a picture of density distributions that, Bailey says, "gives us a first look at BAO in this previously hidden region."

Schlegel says, "There is no other credible way we could have measured BAO at redshifts of two or more. Five years ago it was chancy, but it was the only proposal on the table. We could have failed in any number of ways, but nature was good to us."

White says, "We are seeing back to the matter-dominated universe, when expansion was decelerating and dark energy was hard to see. The transition from decelerating expansion to accelerating expansion was a sharp one, and now we live in a universe dominated by dark energy. The biggest puzzle in cosmology is, why now?"

It's a question BOSS will go far to illuminate as it collects more than a million and a half galaxies and more than 160,000 quasars before SDSS-III is complete. Meanwhile, the Lyman-alpha forest has opened a new view of the ancient universe, one that may come to full fruition with future, more powerful surveys like the proposed BigBOSS.

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by DOE/Lawrence Berkeley National Laboratory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

N.G. Busca, Timothée Delubac, James Rich, Stephen Bailey, Andreu Font-Ribera, David Kirkby, J.-M. Le Goff, Anže Slosar, Éric Aubourg, Julian Bautista, Michael Blomqvist, Bill Carithers, Rupert A.C. Croft, Kyle S. Dawson, Daniel J. Eisenstein, Jean-Christophe Hamilton, Shirley Ho, Khee-Gan Lee, Daniel Margala, Jordi Miralda-Escudé, Pasquier Noterdaeme, Nathalie Palanque-Delabrouille, Isabelle Pâris, Patrick Petitjean, Matthew M. Pieri, Emmanuel Rollinde, Nicholas P. Ross, David J. Schlegel, David H. Weinberg, Martin White, and Christophe Yèche. Baryon Acoustic Oscillations in the Lya forest of BOSS quasars. Astronomy & Astrophysics, 2012; (submitted) [link]

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Little telescope spies gigantic galaxy clusters

Dec. 6, 2012 — Our solar system, with its colorful collection of planets, asteroids and comets, is a fleck in the grander cosmos. Hundreds of billions of solar systems are thought to reside in our Milky Way galaxy, which is itself just a drop in a sea of galaxies.

The rarest and largest of galaxy groupings, called galaxy clusters, can be the hardest to find. That's where NASA's Wide-field Infrared Survey Explorer (WISE) can help. The mission's all-sky infrared maps have revealed one distant galaxy cluster and are expected to uncover thousands more.

These massive structures are collections of up to thousands of galaxies bound together by gravity. They were born out of seeds of matter formed in the very early universe, and grew rapidly by a process called inflation.

"One of the key questions in cosmology is how did the first bumps and wiggles in the distribution of matter in our universe rapidly evolve into the massive structures of galaxies we see today," said Anthony Gonzalez of University of Florida, Gainesville, who led the research program. The results are published in the Astrophysical Journal.

"By uncovering the most massive of galaxy clusters billions of light-years away with WISE, we can test theories of the universe's early inflation period."

WISE completed its all-sky survey in 2011, after surveying the entire sky twice at infrared wavelengths. The 16-inch (40-centimeter) telescope ran out of its coolant as expected in 2010, but went on to complete the second sky scan using two of its four infrared channels, which still functioned without coolant. At that time, the goal of the mission extension was to hunt for more near-Earth asteroids via a project called NEOWISE.

NASA has since funded the WISE team to combine all that data, allowing astronomers to study everything from nearby stars to distant galaxies. These next-generation all-sky images, part of a new project called "AllWISE," will be significantly more sensitive than those previously released, and will be publicly available in late 2013.

Gonzalez and his team plan to use the enhanced WISE data to hunt for more massive galaxy clusters. The first one they spotted, MOO J2342.0+1301, is located more than 7 billion light-years away, or halfway back to the time of the Big Bang. It is hundreds of times more massive than our Milky Way.

By scanning the whole sky with the improved AllWISE data, the team will sleuth out the true monsters of the bunch, clusters as big as thousands of times the mass of the Milky Way, assembled even earlier in the history of the universe.

Galaxy clusters from the first half of the universe are hard to find because they are so far away and because not very many had time to assemble by then. What's more, they are especially hard to see using visible-light telescopes: light that left these faraway structures in visible wavelengths has been stretched into longer, infrared wavelengths due to the expansion of space. WISE can hunt some of these rare colossal structures down because it scanned the whole sky in infrared light.

"I had pretty much written off using WISE to find distant galaxy clusters because we had to reduce the telescope diameter to only 16 inches [40 centimeters] to stay within our cost guidelines, so I am thrilled that we can find them after all," said Peter Eisenhardt, the WISE project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. and an author of the new paper. "The longer exposures from AllWISE open the door wide to see the most massive structures forming in the distant universe."

Other projects planned for the enhanced WISE data include the search for nearby, hidden cool stars, including those with masses as low as planets. If a large planet or tiny star does exist close to our solar system, an object some call "Tyche," then WISE's infrared data may reveal it.

Other authors of the new study are: Daniel Gettings and Conor Mancone of the University of Florida; Adam Stanford of Lawrence Livermore National Laboratory, Livermore, Calif., and University of California, Davis; Mark Brodwin of University of Missouri, Kansas City; Daniel Stern of JPL; Gregory Zeimann of University of California, Davis; Frank Masci of the Infrared Processing and Analysis Center at the California Institute of Technology, Pasadena; Casey Papovich of Texas A&M University, College Station; Ichi Tanaka of the National Astronomical Observatory of Japan; and Edward (Ned) Wright of UCLA.

JPL manages, and operated, WISE for NASA's Science Mission Directorate. Edward Wright is the principal investigator and is at UCLA. The mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://www.nasa.gov/wise , http://wise.astro.ucla.edu and http://www.jpl.nasa.gov/wise .

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by NASA/Jet Propulsion Laboratory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Daniel P. Gettings, Anthony H. Gonzalez, S. Adam Stanford, Peter R. M. Eisenhardt, Mark Brodwin, Conor Mancone, Daniel Stern, Gregory R. Zeimann, Frank J. Masci, Casey Papovich, Ichi Tanaka, Edward L. Wright. The Massive Distant Clusters of WISE Survey: The First Distant Galaxy Cluster Discovered by WISE. The Astrophysical Journal, 2012; 759 (1): L23 DOI: 10.1088/2041-8205/759/1/L23

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here