Excerpt from bulletinstandard.com A pair of pictures of a young star, produced 18 years apart, has revealed a dramatic distinction that is giving astronomers with a exclusive, "real-time" appear at how enormous stars create in the e...
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| Nova Vulpeculae 1670 |
Excerpt from thespacereporter.com
A mystery explosion in the night sky turns out to have been caused by colliding stars.
One of history’s mysteries revolved around a strange explosion observed in the sky in 1670, long thought to have been the first nova on record. Recent research suggests that this enigmatic event was actually a rare stellar collision.
According to a report by Astronomy Magazine, the so-called Nova Vulpeculae of 1670 was more likely the collision of two stars, which shines brighter than a nova but not as brightly as a supernova.
Observations made with various telescopes including the Submillimeter Array, the Effelsburg radio telescope and APEX have revealed the more unusual nature of the light source – a violent collision.
When the event first occurred, it would have been visible from Earth with the naked eye. Now, submillimeter telescopes are needed to detect the traces left in the aftermath of the event.
When first observed, 17th century astronomers described what they saw as a new star appearing in the head of Cygnus, the swan constellation.
Having observed the area of the supposed nova with both submillimeter and radio wavelengths, scientists “have found that the surroundings of the remnant are bathed in a cool gas rich in molecules with a very unusual chemical composition,” said Kaminski.
Researchers concluded that the amount of cool material they observed was too much to have been produced by a nova. The nature of the gas debris best fit with the rare scenario of two stars merging in an explosive collision.
The team’s report was published in the journal Nature.
Karl Menten of the Max Planck Institute called the discovery “the most fun – something that is completely unexpected.”
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Astronomers have discovered a dust-filled ancient galaxy from the very early universe, which debunks earlier theories that earliest galaxies had no dust but gas. Astronomers from the University of Copenhagen used the Very Large Telescope’s X-shooter instrument along with the Atacama Large Millimeter/submillimeter Array and discovered a galaxy, named Galaxy A1689-zD1, which is an ancient galaxy and far from Earth.
The astronomers stated that the galaxy which
they were surprised to discover is far more evolved system than expected. It had a fraction of dust similar to a very mature galaxy, such as the Milky Way. Such dust is vital to life, because it helps form planets, complex molecules and normal stars.
According to the astronomers A1689-zD1 is only observable by virtue of its brightness being amplified more than nine times by a gravitational lens in the form of the spectacular galaxy cluster. Without the gravitational boost, the glow from this very faint galaxy would have been too weak to detect.
The astronomers stated that they are viewing A1689-zD1 when the Universe was only about 700 million years old, which is 5% of its present age. According to them, it is a relatively modest system — much less massive and luminous than many other objects that have been studied before at this stage in the early universe and hence a more typical example of a galaxy at that time.
A1689-zD1 is being observed as it was during the period of reionization, when the earliest stars brought with them a cosmic dawn, illuminating for the first time an immense and transparent universe and ending the extended stagnation of the Dark Ages. Expected to look like a newly formed system, the galaxy surprised the observers with its rich chemical complexity and abundance of interstellar dust.
Dust plays an extremely important role in the universe – both in the formation of planets and new stars.
Darach Watson, Associate Professor at Dark Cosmology Centre, University of Copenhagen, and the lead author of the study, said, “After confirming the galaxy’s distance using the VLT we realized it had previously been observed with ALMA. We didn’t expect to find much, but I can tell you we were all quite excited when we realized that not only had ALMA observed it, but that there was a clear detection. One of the main goals of the ALMA Observatory was to find galaxies in the early Universe from their cold gas and dust emissions — and here we had it!”
The researchers hope that future observations of a large number of distant galaxies could help unravel how frequently such evolved galaxies occur in this very early epoch of the history of the universe.
Excerpt space.com
A strange set of 48 galaxies appears to be rich in dark matter and lacking in stars, suggesting that they may be so-called "failed" galaxies, a new study reports.
The galaxies in question are part of the Coma Cluster, which lies 300 million light-years from Earth and packs several thousand galaxies into a space just 20 million light-years across. To study them, Pieter van Dokkum of Yale University and his colleagues used the Dragonfly Telephoto Array in New Mexico.
The array's eight connected Canon telephoto lenses allow the researchers to search for extremely faint objects that traditional telescope surveys miss. Often, such as when the researchers used the array to search for the faint glow that dark matter might create, the hunt comes up empty.
But when van Dokkum and his colleagues looked toward the Coma Cluster, they found a pleasant surprise.
"We noticed all these faint little smudges in the images from the Dragonfly telescope," van Dokkum told Space.com.
The mysterious blobs nagged at van Dokkum, compelling him to look into the objects further. Fortuitously, NASA's Hubble Space Telescope had recently captured one of these objects with its sharp eye.
"It turned out that they're these fuzzy blobs that look somewhat like dwarf spheroidal galaxies around our own Milky Way," van Dokkum said. "So they looked familiar in some sense … except that if they are at the distance of the Coma Cluster, they must be really huge."
And with very few stars to account for the mass in these galaxies, they must contain huge amounts of dark matter, the researchers said. In fact, to stay intact, the 48 galaxies must contain 98 percent dark matter and just 2 percent "normal" matter that we can see. The fraction of dark matter in the universe as a whole is thought to be around 83 percent.
But before making this claim, the team had to verify that these blobs really are as distant as the Coma Cluster. (In fact, the team initially thought the galaxies were much closer.). But even in the Hubble image the stars were not resolved. If Hubble — one of the most powerful telescopes in existence — can't resolve the stars, those pinpricks of light must be pretty far away, study team members reasoned.
Now, van Dokkum and his colleagues have definitive evidence: They've determined the exact distance to one of the galaxies. The team used the Keck Telescope in Hawaii to look at one of the objects for two hours. This gave them a hazy spectrum, from which they were able to tease out the galaxy's recessional velocity — that is, how fast it is moving away from Earth.
That measure traces back to the Hubble Telescope's namesake. In 1929, American astronomer Edwin Hubble discovered one of the simplest and most surprising relationships in astronomy: The more distant a galaxy, the faster it moves away from the Milky Way.
Today, astronomers use the relationship to measure a galaxy's recessional velocity and thus calculate the galaxy's distance. In this case, the small fuzzy blob observed with Keck was moving away from Earth at 15.7 million mph (25.3 million km/h). That places it at 300 million light-years away from Earth, the distance of the Coma Cluster.
So the verdict is officially in: These galaxies must be associated with the Coma Cluster and therefore must be extremely massive.
"It looks like the universe is able to make unexpected galaxies," van Dokkum said, adding that there is an amazing diversity of massive galaxies.
But the clusters still present a mystery: The team doesn't know why they have so much dark matter and so few stars.
Though they look serene and silent from our vantage on Earth, stars are actually roiling balls of violent plasma. Test your stellar smarts with this quiz.
Normally, the galaxy has such a strong gravitational pull that most of the expelled gas falls back onto the galaxy and forms the next generations of stars. But maybe the strong gravitational pull of the other galaxies in the Coma Cluster interfered with this process, pulling the gas away.
"If that happened, they had no more fuel for star formation and they were sort of stillborn galaxies where they started to get going but then failed to really build up a lot of stars," said van Dokkum, adding that this is the most likely scenario.
Another possibility is that these galaxies are in the process of being ripped apart. But astronomers expect that if this were the case, the galaxies would be distorted and streams of stars would be flowing away from them. Because these effects don't appear, this scenario is very unlikely.
The next step is to try to measure the individual motions of stars within the galaxies. If the team knew those stars' speeds, it could calculate the galaxies' exact mass, and therefore the amount of dark matter they contain. If the stars move faster, the galaxy is more massive. And if they move slower, the galaxy is less massive.
However, this would require a better spectrum than the one the team has right now.
"But it's not outside the realm of what's possible," van Dokkum assured. "It's just very hard."
The original study has been published in Astrophysical Journal Letters. You can read it for free on the preprint site arXiv.org.
Excerpt from thespacereporter.com
According to a NASA statement, telescopes have revealed for the first time that powerful winds emanate from black holes in all directions. These winds are so tremendous that they can actually work to hamper the formation of new stars in the host galaxy.
The two telescopes that were employed by the agency, NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) and ESA’s XMM-Newton, focused on PDS 456, a quasar, an extremely bright type of black hole, over 2 billion light-years away. The results were then analyzed by a team led by Emanuele Nardini of Keele University in the UK.
The two telescopes studied the quasar PDS 456 at five different times throughout 2013 and 2014. By combining low-energy X-ray observations from XMM-Newton with high-energy X-ray observations from NuSTAR, Nardini and team were able to trace iron dispersed by the quasar’s winds. These data demonstrated that the winds blow outwards from the black hole in a spherical front.
Having ascertained the structure of the quasar winds, the team was then able to calculate the strength of the winds. So strong are the quasar winds that they push huge quantities of matter before them, dispersing it outwards through the host galaxy and preventing it from eventually coalescing to generate new stars. In an earlier period of the universe’s history, about 10 billion years ago, supermassive black holes were more abundant and their terrible winds probably had a hand in shaping the current shapes of galaxies.
“For an astronomer, studying PDS 456 is like a paleontologist being given a living dinosaur to study,” said co-author Daniel Stern of NASA’s Jet Propulsion Laboratory. “We are able to investigate the physics of these important systems with a level of detail not possible for those found at more typical distances, during the ‘Age of Quasars.’”
| The new findings have been published in the journal Science. |
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| This artist's illustration depicts the furious cosmic winds streaming out from a monster supermassive black hole as detected by NASA's NuSTAR space telescope and the European Space Agency's XMM-Newton X-ray observatory. |
Except from space.com
A ravenous, giant black hole has belched up a bubble of cosmic wind so powerful that it could change the fate of an entire galaxy, according to new observations.
Researchers using two X-ray telescopes have identified a cosmic wind blowing outward from the supermassive black hole at the center of galaxy PDS 456. Astronomers have seen these winds before, but the authors of the new research say this is the first observation of a wind moving away from the center in every direction, creating a spherical shape.
The wind could have big implications for the future of the galaxy: It will cut down on the black hole's food supply, and slow star formation in the rest of the galaxy, the researchers said. And it's possible that strong cosmic winds are a common part of galaxy evolution — they could be responsible for turning galaxies from bright, active youngsters to quiet middle-agers.
Big eater
The supermassive black hole at the center of PDS 456 is currently gobbling up a substantial amount of food: A smorgasbord of gas and dust surrounds the black hole and is falling into the gravitational sinkhole.As matter falls, it radiates light. The black hole at the center of PDS 456 is devouring so much matter, that the resulting radiation outshines every star in the galaxy. These kinds of bright young galaxies are known as quasars: a galaxy with an incredibly bright center, powered by a supermassive black hole with a big appetite.
New observations of PDS 456 have revealed a bubble of gas moving outward, away from the black hole. Using NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) and ESA’s (European Space Agency) XMM-Newton, the authors of the new research imaged the galaxy on five separate occassions in 2013 and 2014. The researchers say they can show that the photons of light emitted by the in-falling matter are pushing on nearby gas, creating the wind.
Scientists have studied these cosmic winds before, but the authors of the new research say their work goes a step further.
"It tells us that the shape of the wind is not just a narrow beam pointed in our direction. It is really a wind that is flowing in every direction away from the black hole," said Emanuele Nardini, a postdoctoral researcher at Keele University in Staffordshire, England. "With a spherical wind, the amount of mass it carries out is much larger than just a narrow beam."
According to a statement from NASA, galaxy PDS 456 "sustains winds that carry more energy every second than is emitted by more than a trillion suns." Such powerful winds could change the entire landscape of PDS 456, the researchers say. First, the wind will blow through the disk of matter surrounding the black hole — this disk currently serves as the black hole's food supply. The cosmic wind created by the black hole's appetite could significantly reduce or destroy the disk. In other words, the black hole cannot have its cake and eat it, too.
Bright young things
With no matter left to fall into the black hole, the radiation would cease as well. The brilliant center of the quasar will dim. By diminishing the black hole's food supply, they may turn quasars and other "active galaxies" like PDS 456 into quiescent galaxies like the Milky Way. Theorists have proposed that cosmic winds could explain why there are more young active galaxies than old active galaxies."We know that in almost every galaxy, a supermassive black hole resides in the center," said Nardini. "But, most of the galaxies we see today are quiescent, they are not active in any way. The fact that galaxies today are quiescent — we have to find an explanation for that in something that happened a long time ago."
In addition to quenching the radiation from an active black hole, these cosmic winds may slow down star formation in galaxies. The cosmic wind could blow through regions thick with gas and dust, where young stars form, and thin out the fertile stellar soil.
"If you have a black hole with this kind of wind, in millions of years [the winds] will be able to quench star formation and create a galaxy like our own," Nardini said. Stars will still form in the Milky Way, but not at the high rate of many young galaxies.
It's possible that these cosmic winds are a central reason why most galaxies go from being brightly burning active youngsters to quiet middle-agers.
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| The Sculptor Galaxy |
Excerpt from sciencerecorder.com
Starburst galaxies are named for their ability to convert gasses rapidly into new stars, at an accelerated speed that can sometimes be 1,000 times more rapid than your average spiral galaxy, such as the Milky Way. Why the disparity? In order to further investigate the reason that some galaxies seem to “burst” into being, whereas others take the better part of a few billion years, an international team of astronomers analyzed a cluster of star-forming gas clouds in the heart of NGC 253 – the Sculptor Galaxy, with the aid of the Atacama Large Millimeter/submillimeter Array (ALMA). The Sculptor Galaxy is among starburst galaxies closest to the Milky Way.
“All stars form in dense clouds of dust and gas,” said Adam Leroy, in an interview with Astronomy magazine. Leroy is an astronomer at Ohio State University in Columbus. “Until now, however, scientists struggled to see exactly what was going on inside starburst galaxies that distinguished them from other star-forming regions.”
Therefore, Leroy and his colleagues turn to the ALMA which is capable of examining star changing structures even in systems as distant as Sculptor. Already, they have successfully charted distribution and movement of various molecules within several clouds located at the Sculptor Galaxy’s core.
Because NGC 253, which is disk-shaped, is in the stages of a very intense starburst and located approximately 11.5 million light-years from home, it is the perfect target for study. ALMA picks it up with remarkable precision and resolution, so much so that the team was able to isolate and identify ten different stellar ‘nurseries,’ in which stars were in the process of forming. To appreciate the magnitude of this feat, it would have been impossible with previous telescopes, which blurred the regions together into one glow.
“There is a class of galaxies and parts of galaxies, we call them starbursts, where we know that gas is just plain better at forming stars,” said Leroy. “To understand why, we took one of the nearest such regions and pulled it apart — layer by layer — to see what makes the gas in these places so much more efficient at star formation.”
More importantly, they recognized the distribution of several 40 millimeter-wavelength “signatures,” that given off by various molecules at the center of Sculptor Galaxy, signaling that a number of conditions were responsible for the development of these stars. This accounts for the diversity of the states of different stars corresponding to where they are found in star-forming clouds. One important compound, all too familiar and unwelcome on Earth, carbon monoxide (CO), correlates with massive envelopes of gases that are less dense within the stellar nurseries. Others, such as hydrogen cyanide (HCN), were present in the more dense reaches of active star formation. The rarer the molecules, for example, H13CN and H13CO+, suggest regions that are even denser.
Indeed, when the data was compared, researchers found that the gas clouds of the Sculptor Galaxy were ten times denser than those found in spiral galaxies, suggesting that because the clouds are so tightly packed, they can form star clusters much more rapidly than the Milky Way. At the same time, they give us further insight as to how stars are born, showing us the physical changes along the way, allowing astronomers a working model to compare with our own galaxy.
“These differences have wide-ranging implications for how galaxies grow and evolve,” concluded Leroy. “What we would ultimately like to know is whether a starburst like Sculptor produces not just more stars, but different types of stars than a galaxy like the Milky Way. ALMA is bringing us much closer to that goal.”
A view of the excavations at Helike. Drekis, Wikimedia CommonsExcerpt from popular-archaeology.com A team of scholars and students will return to explore and investigate the site now thought to be the remains of the lost city of Helike, the lege...
Excerpt from spacedaily.com For nearly half a century, theoretical physicists have made a series of discoveries that certain constants in fundamental physics seem extraordinarily fine-tuned to allow for the emergence of a life-enabling universe.Thi...
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| The first image of the sun captured by NASA's Nuclear Spectroscopic Telescope Array (NuSTAR), which is sensitive to high-energy X-ray light. X-rays seen by NuSTAR show up as green and blue in the photo, which is overlaid on an image taken by NASA's Solar Dynamics Observatory. |
Excerpt from
csmonitor.com
A NASA space telescope designed to peer at faraway black holes has snapped a stunning image of the sun, showing that its sensitive X-ray eyes can investigate mysteries in Earth's own neighborhood.
The new image, which was taken by NASA's NuSTAR spacecraft (short for Nuclear Spectroscopic Telescope Array), is the best-ever view of the sun in high-energy X-ray light, space agency officials said. The photo, and others taken by NuSTAR in the future, should help researchers learn more about our star, they added.
"NuSTAR will give us a unique look at the sun, from the deepest to the highest parts of its atmosphere," NuSTAR team member David Smith, of the University of California, Santa Cruz, said in a statement.
The new image, which was released Monday (Dec. 22), overlays NuSTAR observations (seen in blue and green) onto an image of the sun captured by NASA's Solar Dynamics Observatory spacecraft.
NuSTAR solar observations might also reveal more about the nature of dark matter, the mysterious stuff thought to make up most of the material universe.
Dark matter apparently does not emit or absorb light — hence its name — and nobody knows for sure what it's made of. A number of exotic particles have been proposed as dark matter constituents, including weakly interacting massive particles, sterile neutrinos and axions.
If axions exist, NuSTAR may see signs of them — patches of X-rays in the center of the sun — NASA officials said.
Excerpt from natmonitor.com
An international team of researchers, during a survey of the Mariana trench has found a new species of fish and found evidence of other known species living at new depths.
The Mariana trench is the deepest known part of the ocean, far too deep for humans to visit. At the deepest part of the trench the water pressure would be the equivalent of “one person trying to support 50 jumbo jets” according to the National Oceanic and Atmospheric Association (NOAA).
The survey was conducted using the Hadal-Lander, a vehicle built in Aberdeen Scotland for deep sea research. The vehicle is equipped with a variety of high resolution cameras, scientific instruments and an array of small baited funnel traps used to lure and trap small animals.
The researchers deployed the craft an unprecedented 92 times along the trench at depths ranging from 5000 – 10,600 meters.
At a depth of 8145 meters the team observed a kind of snail fish, 500 meters deeper than any fish has been observed previously.
“This really deep fish did not look like anything we had seen before, nor does it look like anything we know of, it is unbelievably fragile, with large wing-like fins and a head resembling a cartoon dog,” said Dr Alan Jamieson from the University of Aberdeen in a statement.
During the expedition the team also captured images of a ‘supergiant’ amphipod. These extremely large crustacean was originally discovered in traps off of New Zealand in 2012 but has never before been observed in its natural habitat. Video footage collected by the team shows the animal swimming, feeding and fighting off predators. A number of other species were also filmed, setting new depth records for three fish families.
NASA's Mars Reconnaissance Orbiter has snapped an image of a mysterious circular landform that scientists say could be volcanic in origin.Excerpt from csmonitor.comA NASA Mars probe has photographed a strange Red Planet landform that resembles a fres...
A weird circular landform recently spotted on the surface of Mars might look like a deformed waffle--or maybe the surface of a human brain. But as to what the strange feature really is--and how it got there--scientists at this point have only opinions....
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