(Phys.org)—The research team working with the LIGO project has proposed that the data gleaned from the discovery of gravity waves last year allows for calculating the likely level of cosmic background noise due to gravitational waves, and that it is much greater than previous models have suggested. In their paper published in Physical Review Letters, researchers with the LIGO Scientific Collaboration along with a companion group from the Virgo Collaboration, describe their reasoning behind their estimates and why they believe they will be able to offer more support for their theory within just a few years.

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06 April 2016

Astronomers have uncovered one of the biggest supermassive black holes, with the mass of 17 billion Suns, in an unlikely place: the centre of a galaxy that lies in a quiet backwater of the Universe. The observations, made with the NASA/ESA Hubble Space Telescope and the Gemini Telescope in Hawaii, indicate that these monster objects may be more common than once thought. The results of this study are released in the journal Nature.

Until now, the biggest supermassive black holes – those having more than 10 billion times the mass of our Sun – have only been found at the cores of very large galaxies in the centres of massive galaxy clusters. Now, an international team of astronomers using the NASA/ESA Hubble Space Telescope has discovered a supersized black hole with a mass of 17 billion Suns in the centre of the rather isolated galaxy NGC 1600.
NGC 1600 is an elliptical galaxy which is located not in a cluster of galaxies, but in a small group of about twenty. The group is located 200 million light-years away in the constellation Eridanus. While finding a gigantic supermassive black hole in a massive galaxy within a cluster of galaxies is to be expected, finding one in an average-sized galaxy group like the one surrounding NGC 1600 is much more surprising.
"Even though we already had hints that the galaxy might host an extreme object in the centre, we were surprised that the black hole in NGC 1600 is ten times more massive than predicted by the mass of the galaxy," explains lead author of the study Jens Thomas from the Max Planck-Institute for Extraterrestrial Physics, Germany.

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Multiple teams finally have the material they need to repeat enigmatic experiment.

Davide Castelvecchi

05 April 2016

It is the elephant in the room for dark-matter research: a claimed detection that is hard to believe, impossible to confirm and surprisingly difficult to explain away. Now, four instruments that will use the same type of detector as the collaboration behind the claim are in the works or poised to go online. Within three years, the experiments will be able to either confirm the existence of dark matter — or rule the claim out once and for all, say the physicists who work on them.

“This will get resolved,” says Frank Calaprice of Princeton University in New Jersey, who leads one of the efforts.

The original claim comes from the DAMA collaboration, whose detector sits in a laboratory deep under the Gran Sasso Massif, east of Rome. For more than a decade, it has reported overwhelming evidence1 for dark matter, an invisible substance thought to bind galaxies together through its gravitational attraction. The first of the new detectors to go online, in South Korea, is due to start taking data in a few weeks. The others will follow over the next few years in Spain, Australia and, again, Gran Sasso. All will use sodium iodide crystals to detect dark matter, which no full-scale experiment apart from DAMA’s has done previously.

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Andromeda's pulsing neutron star. Credit: Andromeda: ESA/Herschel/PACS/SPIRE/J. Fritz, U. Gent/XMM-Newton/EPIC/W. Pietsch, MPE; data: P. Esposito et al. (2016)

Decades of searching in the Milky Way's nearby 'twin' galaxy Andromeda have finally paid off, with the discovery of an elusive breed of stellar corpse, a neutron star, by ESA's XMM-Newton space telescope.

Andromeda, or M31, is a popular target among astronomers. Under clear, dark skies it is even visible to the naked eye. Its proximity and similarity in structure to our own spiral galaxy, the Milky Way, make it an important natural laboratory for astronomers. It has been extensively studied for decades by telescopes covering the whole electromagnetic spectrum.
Despite being extremely well studied, one particular class of object had never been detected: spinning neutron stars.
Neutron stars are the small and extraordinarily dense remains of a once-massive star that exploded as a powerful supernova at the end of its natural life. They often spin very rapidly and can sweep regular pulses of radiation towards Earth, like a lighthouse beacon appearing to flash on and off as it rotates.

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Comet 67P and Rosetta are now just over 400 million km from the Sun, and receding

Perfectly backlit by our star. This is how Comet 67P was pictured this week by the Rosetta spacecraft.

The European Space Agency (Esa) probe was a few hundred km "downstream" of all the vapour and dust being vented from the icy dirt-ball.
Even though the duck-shaped object is heading out of the inner Solar System, it remains classically active.
Rosetta will continue to study the comet until controllers direct it to make a "landing" in September.
Mission officials will endeavour to make this touchdown a gentle one, to ensure data is returned for as long as possible. But it will bring the whole venture to an end.

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Scientists are sitting on top of the world after this monumental discovery and are eager to keep exploring the universe

More than a billion years ago, in a galaxy far, far away, two black holes executed the final steps in a fast-footed pas de deux, concluding with a final embrace so violent it released more energy than the combined output of every star in every galaxy in the observable universe. Yet, unlike starlight, the energy was dark, being carried by the invisible force of gravity. On September 14, 2015, at 5:51 a.m. Eastern Daylight Time, a fragment of that energy, in the form of a “gravitational wave,” reached Earth, reduced by its vast transit across space and time to a mere whisper of its thunderous beginning

As far as we know, Earth has been bathed in this type of gravitational disturbance before. Frequently. The difference this time is that two stupendously precise detectors, one in Livingston, Louisiana, and the other in Hanford, Washington, were standing at the ready. When the gravitational wave rolled by, it tickled the detectors, providing the unmistakable signature of colliding black holes on the other side of the universe and marking the beginning of a new chapter in humankind’s exploration of the cosmos.

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Though the recent discovery of GW150914 is a thrilling success in the field of gravitational-wave astronomy, LIGO is only one tool the scientific community is using to hunt for these elusive signals. After 10 years of unsuccessful searching, how likely is it that pulsar-timing-array projects will make their own first detection soon?

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A Japanese team of scientists are attempting to detect so-called gravitational waves, space-time ripples first theorised by Albert Einstein 100 years ago.

25 MAR 2016 - 8:42 PM UPDATED 25 MAR 2016 - 8:42 PM

Japanese scientists have begun a test run of underground telescope KAGRA to detect gravitational waves and gain a better understanding of the universe through their observations, Japan's Kyodo agency reports.

The test run, which began on Friday and will continue until Thursday, comes a month after a US-led team of scientists said they had identified the gravitational waves, theorised 100 years ago by Albert Einstein.

The KAGRA telescope is installed inside an L-shaped tunnel with each arm extending 3km and located more than 200m underground at the Kamioka mine site in the central Gifu prefecture to minimise seismic noise.

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Artist’s impression of a quasar. In the quasar OJ 287, a secondary supermassive black hole orbits the primary, occasionally punching through the accretion disk surrounding the primary. [ESO/M. Kornmesser]

This past December, researchers all over the world watched an outburst from the enormous black hole in OJ 287 — an outburst that had been predicted years ago using the general theory of relativity.

Outbursts from Black-Hole Orbits

OJ 287 is one of the largest supermassive black holes known, weighing in at 18 billion solar masses. Located about 3.5 billion light-years away, this monster quasar is bright enough that it was first observed as early as the 1890s. What makes OJ 287 especially interesting, however, is that its light curve exhibits prominent outbursts roughly every 12 years.

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The LHC has begun circulating proton beams again, after a 13-week maintenance break. What are the next steps?

It was definitely a “maintenance break”, not a holiday. Those accelerator people don’t care about holidays, as indicated by that fact that, like last year, they are working over Easter. Proton beams were injected into the ring and circulated today, an important step on the way to more physics in 2016.

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Researchers have finally witnessed, in visible light wavelengths, the “shock breakout” of a supernova—the exact moment when the expanding blast wave from a vanishing star lastly explodes the outer stellar layers and makes its outstanding entry onto the cosmic stage. The recent supernova results signify the proverbial needle in a haystack—an international group of researcher examined 3 years’ worth of data, in which Kepler taken pictures every other 30 minutes of some 50 trillion stars dispersed amid 500 remote galaxies.

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Successful test drive for space-based gravitational-wave detector
Mission paves the way for planned €1-billion space observatory.

Elizabeth Gibney
25 February 2016

Scientists have long dreamed of launching a constellation of detectors into space to observe gravitational waves — the ripples in space-time predicted by Albert Einstein and observed for the first time earlier this month.

That dream is now a step closer to reality. Researchers working on a €400-million (US$440-million) mission to try out the necessary technology in space for the first time — involving firing lasers between metal cubes in free fall — have told Nature that the initial test drive is performing just as well as they had hoped.

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Paris, 16 March 2016
"A source accelerating Galactic cosmic rays to unprecedented energy discovered at the centre of the Milky Way"

For more than ten years the H.E.S.S. observatory in Namibia, run by an international collaboration of 42 institutions in 12 countries, has been mapping the centre of our galaxy in very-high-energy gamma rays. These gamma rays are produced by cosmic rays from the innermost region of the Galaxy. A detailed analysis of the latest H.E.S.S. data, published on 16th March 2016 in Nature, reveals for the first time a source of this cosmic radiation at energies never observed before in the Milky Way: the supermassive black hole at the centre of the Galaxy, likely to accelerate cosmic rays to energies 100 times larger than those achieved at the largest terrestrial particle accelerator, the LHC at CERN.

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Louie Psihoyos / Corbis

The Arecibo Observatory in Puerto Rico, which has spotted the first example of a repeating fast radio burst.

One paper suggests that fast radio bursts can repeat, but a finding on the origin of another burst is in doubt.

Mark Zastrow
02 March 2016

Three reports within a week have astronomers aflutter about the puzzling origins of short, bright pulses of radio waves called fast radio bursts (FRBs).

Last week, astronomers said that they had1 identified the origins of an FRB for the first time — pinpointing the signal to a distant galaxy. And a paper published today3 offers a different clue to the origins of FRBs, which have baffled astronomers since they were first observed nine years ago. It reports the discovery of a repeating signal: a surprise because all 17 known bursts so far have been one-off blips.

But sceptics have questioned the first work, recording telescope observations within days of the announcement that cast doubt on the finding2.

Origin story

On 24 February, astronomers announced that they had identified the origin of an FRB in a galaxy 1.9 billion parsecs (6 billion light years) away, probably produced by a collision between two neutron stars1. A network of telescopes had scanned the area of sky in which an FRB had been picked up by the Parkes radio telescope in New South Wales, Australia, and had discovered a fading afterglow of radio waves in an elliptical galaxy. The odds of finding such a radio signal by chance were just one or two in a thousand, wrote the team led by Evan Keane of the Square Kilometre Array Organisation, which is headquartered at the Jodrell Bank Observatory outside Manchester, UK.

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L. G. Spitler, P. Scholz, J. W. T. Hessels, S. Bogdanov, A. Brazier, F. Camilo, S. Chatterjee, J. M. Cordes, F. Crawford, J. Deneva, R. D. Ferdman, P. C. C. Freire, V. M. Kaspi, P. Lazarus, R. Lynch, E. C. Madsen, M. A. McLaughlin, C. Patel, S. M. Ransom, A. Seymour, I. H. Stairs, B. W. Stappers, J. van Leeuwen & W. W. Zhu

Nature (2016) doi:10.1038/nature17168

Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections9. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events10. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst4. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

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