TAT Blog interesting astrophysics stories

A bizarre gamma-ray burst breaks the rules for these cosmic eruptions

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One possible origin for GRB 211211A, shown in this illustration, is a pair of compact stars merging (bright dots in the center) and emitting jets of radiation (green and purple beams). Heavy elements forming in the clouds of matter surrounding the stars emit light that is known as a kilonova. SAMUELE RONCHINI/GSSI 2022

By Lisa Grossman
8.12.2022

Astronomers have spotted a bright gamma-ray burst that upends previous theories of how these energetic cosmic eruptions occur.

For decades, astronomers thought that GRBs came in two flavors, long and short — that is, lasting longer than two seconds or winking out more quickly. Each type has been linked to different cosmic events. But about a year ago, two NASA space telescopes caught a short GRB in long GRB’s clothing: It lasted a long time but originated from a short GRB source.

“We had this black-and-white vision of the universe,” says astrophysicist Eleonora Troja of the Tor Vergata University of Rome. “This is the red flag that tells us, nope, it’s not. Surprise!”

This burst, called GRB 211211A, is the first that unambiguously breaks the binary, Troja and others report December 7 in five papers in Nature and Nature Astronomy.

Prior to the discovery of this burst, astronomers mostly thought that there were just two ways to produce a GRB. The collapse of a massive star just before it explodes in a supernova could make a long gamma-ray burst, lasting more than two seconds (SN: 10/28/22). Or a pair of dense stellar corpses called neutron stars could collide, merge and form a new black hole, releasing a short gamma-ray burst of two seconds or less.

 

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IceCube neutrinos give us first glimpse into the inner depths of an active galaxy

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Hubble image of the spiral galaxy NGC 1068. Credit: NASA/ESA/A. van der Hoeven

Posted on November 3, 2022 by Staff

The detection was made at the National Science Foundation-supported IceCube Neutrino Observatory, a massive neutrino telescope encompassing 1 billion tons of instrumented ice at depths of 1.5 to 2.5 kilometers below Antarctica’s surface near the South Pole. This unique telescope, which explores the farthest reaches of our universe using neutrinos, reported the first observation of a high-energy astrophysical neutrino source in 2018. The source, TXS 0506+056, is a known blazar located off the left shoulder of the Orion constellation and 4 billion light-years away.

“One neutrino can single out a source. But only an observation with multiple neutrinos will reveal the obscured core of the most energetic cosmic objects,” says Francis Halzen, a professor of physics at the University of Wisconsin–Madison and principal investigator of IceCube. He adds, “IceCube has accumulated some 80 neutrinos of teraelectronvolt energy from NGC 1068, which are not yet enough to answer all our questions, but they definitely are the next big step towards the realization of neutrino astronomy.”

Unlike light, neutrinos can escape in large numbers from extremely dense environments in the universe and reach Earth largely undisturbed by matter and the electromagnetic fields that permeate extragalactic space. Although scientists envisioned neutrino astronomy more than 60 years ago, the weak interaction of neutrinos with matter and radiation makes their detection extremely difficult. Neutrinos could be key to our queries about the workings of the most extreme objects in the cosmos.

 

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Scientists Just Detected a Colossal Gamma-Ray Burst, And It's a Record-Breaker

undefinedAn artist's impression of a gamma-ray burst. (ESO/A. Roquette)

12 October 2022
By MICHELLE STARR

Observatories around the world have just detected a colossal flare of extremely energetic radiation described as "record-breaking".

The event, first detected on October 9, was so bright that it was initially confused for an event closer to home. Initially dubbed Swift J1913.1+1946, it was thought to be a brief flash of X-rays from a not-too-distant source. It was only through further analysis that astronomers discovered the true nature of the glow – a gamma-ray burst, one of the most violent explosions in the Universe, now re-named GRB221009A.

Though further away, it was still one of the closest seen yet, just 2.4 billion light-years away. Moreover, this exceptionally bright gamma-ray burst appears to be the most energetic ever detected, coming in at up to 18 teraelectronvolts.

To be clear, though this proximity happens to be 20 times closer than the average long gamma-ray burst, it poses absolutely no danger to life on Earth.

Rather, it's tremendously exciting – an event that could shed new light (pun intended) on these fascinating explosions. Although its closeness makes it appear brighter in our sky, GRB221009A is possibly the most intrinsically bright gamma-ray burst we've ever seen.

 

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A New FRB Signal Has Buzzed Nearly 2,000 Times in Just Two Months, Raising a Mystery

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Still from a NASA animation of a magnetar emitting a powerful flare. (NASA)

24 September 2022
By MICHELLE STARR

We have detected a strange new signal from across the chasm of time and space.

A repeating fast radio burst source detected last year was recorded spitting out a whopping 1,863 bursts over 82 hours, amid a total of 91 hours of observation.

This hyperactive behavior has allowed scientists to characterize not just the galaxy that hosts the source and its distance from us, but also what the source is.

The object, named FRB 20201124A, was detected with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China and described in a new paper led by astronomer Heng Xu of Peking University in China.

 

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Crumbling planets might trigger repeating fast radio bursts

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Interactions between a planet and a magnetic neutron star (illustrated) might be the source of repeating, millisecond-long bursts of cosmic radio waves. MARK GARLICK/SCIENCE PHOTO LIBRARY/GETTY

It’s one more hypothesis among many for the source of these flares

By Liz Kruesi
APRIL 18, 2022

Fragmenting planets sweeping extremely close to their stars might be the cause of mysterious cosmic blasts of radio waves.

Milliseconds-long fast radio bursts, or FRBs, erupt from distant cosmic locales. Some of these bursts blast only once and others repeat. A new computer calculation suggests the repetitive kind could be due to a planet interacting with its magnetic host star, researchers report in the March 20 Astrophysical Journal.

FRBs are relative newcomers to astronomical research. Ever since the first was discovered in 2007, researchers have added hundreds to the tally. Scientists have theorized dozens of ways the two different types of FRBs can occur, and nearly all theories include compact, magnetic stellar remnants known as neutron stars. Some ideas include powerful radio flares from magnetars, the most magnetic neutron stars imaginable (SN: 6/4/20). Others suggest a fast-spinning neutron star, or even asteroids interacting with magnetars (SN: 2/23/22).

 

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Here’s what the next 10 years of space science could look like

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In the new decadal survey, researchers recommend building a planet-hunting space telescope that takes inspiration from a previously proposed mission called HabEx (illustrated). IMAGE COURTESY OF SCOTT GAUDI

By Maria Temming
4 HOURS AGO

The Astronomy and Astrophysics Decadal Survey is basically a sneak preview of the next 10 years of U.S. space science. Every decade, experts assembled by the National Academies of Sciences, Engineering and Medicine collect input from astronomers nationwide to recommend a prioritized list of projects to policy makers and federal agencies. Past to-do lists have been topped by specific big-ticket items, such as the James Webb Space Telescope and the Nancy Grace Roman Space Telescope (SN: 10/6/21; SN: 8/13/10). But this year, astronomers are shaking things up.

The latest decadal survey, which charts the course for U.S. astronomy and astrophysics from 2022 to 2032, recommends that NASA create a new program to develop several major space telescopes at a time. Investing early in multiple mission concepts could curb the risk of individual missions becoming too unwieldy and expensive, according to the report released November 4.

 

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A rush to watch a supernova exposed its last gasp before exploding

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Scientists spotted an exploding star in one of a pair of galaxies known as the Butterfly galaxies (shown). Observations of that supernova (bright spot in the zoomed-in view) in the hours and days after it went off showed details of the star’s life just before death. NASA, ESA, RYAN FOLEY/UCSC, JOSEPH DEPASQUALE/STSCI

 

By Emily Conover
NOVEMBER 2, 2021 

A mad scramble to observe the moments after a star’s death is helping scientists understand how the star lived out its last year.

Astronomers reported the exploding star just 18 hours after it flared up on March 31, 2020, in a galaxy about 60 million light-years away from Earth in the Virgo cluster. The supernova occurred in part of the sky already watched by NASA’s Transiting Exoplanet Survey Satellite, which images large portions of the sky every 30 minutes (SN: 1/8/19). And a team of scientists quickly realized that data would track precisely how the eruption brightened over time, making it ideal for further study.

To learn even more, the team leapt into action, viewing the supernova with a variety of telescopes in the hours and days that followed, even orchestrating a last-minute change of plans for the Hubble Space Telescope. That provided the supernova’s spectrum, an accounting of its light broken up by wavelength, at various moments after the blast.

All that data revealed that in the last year of its life, the star had spewed some of its outer layers into space, researchers report October 26 in Monthly Notices of the Royal Astronomical Society. The amount of material ejected was about 0.23 times the mass of the sun, the team estimates. When the supernova went off, it launched a shock wave that plowed through that material shortly after the explosion, generating light picked up by the telescopes.

 

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When a nearby star goes supernova, scientists will be ready

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STELLAR SWOON A simulation of a supernova tracks the turmoil in the center of a dying star in the moments after its core collapses. The collapse creates a shock wave (blue line) that travels outward, blasting the star apart. Red colors represent material hurtling outward, blues represent inward motion. The surfaces of the lumpy shapes have equal entropy, which is related to temperature. T. MELSON, H.-T. JANKA AND A. MAREK/ASTROPHYS. J. LETT. 2015

By Emily Conover
FEBRUARY 8, 2017

 

Almost every night that the constellation Orion is visible, physicist Mark Vagins steps outside to peer at a reddish star at the right shoulder of the mythical figure. “You can see the color of Betelgeuse with the naked eye. It’s very striking, this red, red star,” he says. “It may not be in my lifetime, but one of these days, that star is going to explode.”

With a radius about 900 times that of the sun, Betelgeuse is a monstrous star that is nearing its end. Eventually, it will no longer be able to support its own weight, and its core will collapse. A shock wave from that collapse will speed outward, violently expelling the star’s outer layers in a massive explosion known as a supernova. When Betelgeuse detonates, its cosmic kaboom will create a light show brighter than the full moon, visible even during the daytime. It could happen tomorrow, or a million years from now.

 

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When James Webb launches, it will have a bigger to-do list than 1980s researchers suspected

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Engineers work on the James Webb Space Telescope’s primary mirror. The 18 hexagonal mirror segments are made of lightweight yet tough beryllium and coated with a thin layer of gold to boost reflectivity. DESIREE STOVER/NASA

Lisa Grossman
OCTOBER 6, 2021

Delays for the space telescope mean there’ll be more cool science to do

The James Webb Space Telescope has been a long time coming. When it launches later this year, the observatory will be the largest and most complex telescope ever sent into orbit. Scientists have been drafting and redrafting their dreams and plans for this unique tool since 1989.

The mission was originally scheduled to launch between 2007 and 2011, but a series of budget and technical issues pushed its start date back more than a decade. Remarkably, the core design of the telescope hasn’t changed much. But the science that it can dig into has. In the years of waiting for Webb to be ready, big scientific questions have emerged. When Webb was an early glimmer in astronomers’ eyes, cosmological revolutions like the discoveries of dark energy and planets orbiting stars outside our solar system hadn’t yet happened.

“It’s been over 25 years,” says cosmologist Wendy Freedman of the University of Chicago. “But I think it was really worth the wait.”

An audacious plan
Webb has a distinctive design. Most space telescopes house a single lens or mirror within a tube that blocks sunlight from swamping the dim lights of the cosmos. But Webb’s massive 6.5-meter-wide mirror and its scientific instruments are exposed to the vacuum of space. A multilayered shield the size of a tennis court will block light from the sun, Earth and moon.

For the awkward shape to fit on a rocket, Webb will launch folded up, then unfurl itself in space (see below, What could go wrong?).

 

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Some fast radio bursts come from the spiral arms of other galaxies

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A Hubble Space Telescope image (left) of a galaxy known to host a ‘fast radio burst’ helps ID where in the galaxy the blast originated (oval). After image processing (right), the burst’s origin appears centered on one of the galaxy’s spiral arms. NASA, ESA, ALEXANDRA MANNINGS/UNIVERSITY OF CALIFORNIA SANTA CRUZ, WEN-FAI FONG/NORTHWESTERN UNIVERSITY, ALYSSA PAGAN/STSCI

Locating the bursts’ homes suggests a connection to ordinary, young stars

By Lisa Grossman  JUNE 1, 2021 

Five brief, bright blasts of radio waves from deep space now have precise addresses.

The fast radio bursts, or FRBs, come from the spiral arms of their host galaxies, researchers report in a study to appear in the Astrophysical Journal. The proximity of the FRBs to sites of star formation bolsters the case for run-of-the-mill young stars as the origin of these elusive, energetic eruptions.

“This is the first such population study of its kind and provides a unique piece to the puzzle of FRB origins,” says Wen-fai Fong, an astronomer at Northwestern University in Evanston, Ill.

FRBs typically last a few milliseconds and are never seen again. Because the bursts are so brief, it’s difficult to nail down their precise origins on the sky. Although astronomers have detected about 1,000 FRBs since the first was reported in 2007, only 15 or so have been traced to a specific galaxy.

 

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Stars made of antimatter could lurk in the Milky Way

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Fourteen celestial sources of gamma rays (colored dots in this all-sky map of the Milky Way; yellow indicates bright sources and blue shows dim sources) may come from stars made of antimatter. SIMON DUPOURQUÉ/IRAP

If true, the preliminary find might mean some antimatter survived to the present day

 

By Maria Temming
APRIL 26, 2021

Fourteen pinpricks of light on a gamma-ray map of the sky could fit the bill for antistars, stars made of antimatter, a new study suggests.

These antistar candidates seem to give off the kind of gamma rays that are produced when antimatter — matter’s oppositely charged counterpart — meets normal matter and annihilates. This could happen on the surfaces of antistars as their gravity draws in normal matter from interstellar space, researchers report online April 20 in Physical Review D.

“If, by any chance, one can prove the existence of the antistars … that would be a major blow for the standard cosmological model,” says Pierre Salati, a theoretical astrophysicist at the Annecy-le-Vieux Laboratory of Theoretical Physics in France not involved in the work. It “would really imply a significant change in our understanding of what happened in the early universe.”

 

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A surprising swarm of black holes found in nearby globular cluster

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The globular cluster NGC 6397 is one of the closest to Earth at a distance of 7,800 light years. Analysis of multiple observations over several years with the Hubble Space Telescope reveals the gravitational effects of multiple stellar-mass black holes. Image: NASA, ESA, T. Brown, S. Casertano, and J. Anderson (STScI)

 

11 February 2021 Astronomy Now

 

Black holes are thought to range between two extremes: from stellar-mass black holes that form when single, massive stars collapse to the supermassive behemoths millions to billions of times the mass of the Sun. Intermediate-mass holes, with the gravitational heft of hundreds to tens of thousands of stars, are thought to bridge the gap between the two extremes, but only a few candidates have been identified to date.

Likely habitats for intermediate black holes are the cores of globular clusters, the concentrated assemblies of ancient stars that are nearly as old as the cosmos. Researchers using the Hubble Space Telescope observed one of the closest globulars to Earth – NGC 6397 – looking for stellar motions that might indicate the gravitational influence of an intermediate black hole.

Instead, they were surprised to find signs of multiple stellar-mass black holes.

“We found very strong evidence for an invisible mass in the dense core of the globular cluster, but we were surprised to find that this extra mass is not ‘point-like’ but extended to a few percent of the size of the cluster,” said Eduardo Vitral of the Paris Institute of Astrophysics.

 

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Somehow, a Monstrous Supermassive Black Hole Has Gone Missing

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MICHELLE STARR 18 DECEMBER 2020

The Universe is full of galaxy clusters, but Abell 2261 is in a class of its own. In the galaxy in the centre of the cluster, where there should be one of the biggest supermassive black holes in the Universe, astronomers have been able to find no trace of such an object.

And a new search has only made the absence more puzzling: if the supermassive black hole got yeeted out into space, it should have left evidence of its passage. But there's no sign of it in the material surrounding the galactic centre, either.

But this means that constraints can be placed on what the supermassive black hole - if it is there, evading detection - is doing.

Galaxy clusters are the largest known gravitationally bound structures in the Universe. Typically, they're groups of hundreds to thousands of galaxies that are bound together, with one huge, abnormally bright galaxy at or close the centre, known as the brightest cluster galaxy (BCG).

But even among BCGs, Abell 2261's BCG (named, in fact, A2261-BCG, and located about 2.7 billion light-years away) stands out. It's about a million light-years across - up to to 10 times the size of the Milky Way galaxy - and it has a huge, puffy core 10,000 light-years across, the largest galactic core ever seen.

 

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Star-crossed planets: Incredibly rare 'Christmas Star' to appear for the 1st time in 800 years

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NASA image

By Ashley Strickland, CNN | Posted - Dec. 7, 2020

The two largest planets in our solar system are coming closer together than they have been since the Middle Ages, and it's happening just in time for Christmas.

So, there are some things to look forward to in the final month of 2020.

On the night of Dec. 21, the winter solstice, Jupiter and Saturn will appear so closely aligned in our sky that they will look like a double planet. This close approach is called a conjunction.

"Alignments between these two planets are rather rare, occurring once every 20 years or so, but this conjunction is exceptionally rare because of how close the planets will appear to one another," said Rice University astronomer and professor of physics and astronomy Patrick Hartigan in a statement.

"You'd have to go all the way back to just before dawn on March 4, 1226, to see a closer alignment between these objects visible in the night sky."

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See also a beautiful webpage from University of Exeter

 

 

 

A Radio Flare from Colliding Stars?

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When neutron stars collide, the shell of expanding ejecta can interact with the surrounding interstellar medium, producing long-lived radio flaring. [NASA's Goddard Space Flight Center/CI Lab]

By Susanna Kohler on 11 December 2020

When a pair of neutron stars collide, they emit a fireworks show. Could some of the low-energy light produced in these mergers be detectable years later? A team of scientists thinks so — and they’re pretty sure they’ve found an example.

A Rainbow of Signals


In addition to gravitational waves, a slew of electromagnetic radiation is produced in the merger of two neutron stars, spanning the spectrum from gamma rays to radio waves.

In 2017, the now-famous neutron star collision GW170817 gave us a first look at this expected emission: it revealed a short gamma-ray burst, infrared and optical light from ejecta in a kilonova, and relatively short-lived X-ray and radio afterglows caused by high-speed outflows.

But there’s one expected type of emission that was missing from GW170817, and it’s never before been spotted in any neutron star collision: radio flaring.

 

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Nugget Galaxies Cross in the Sky

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The canonical Einstein Cross, the quadruply lensed quasar Q2237+030, is seen in this Hubble image. A new study has found two additional Einstein Crosses created by the lensing of compact galaxies. [NASA, ESA, and STScI]

By Susanna Kohler on 9 December 2020

Seeing quadruple? In a rare phenomenon, some distant objects can appear as four copies arranged in an “Einstein cross”. A new study has found two more of these unusual sights — with an unexpected twist.

Searching for Rare Crosses


Gravitational lensing — the bending of light by the gravity of massive astronomical objects — can do some pretty strange things. One of lensing’s more striking creations is the Einstein cross, a configuration of four images of a distant, compact source created by the gravitational pull of a foreground object (which is usually visible in the center of the four images).

 The canonical example of this phenomenon is the Einstein Cross, a gravitationally lensed object called QSO 2237+0305, seen in the cover image above. In this case, as with the majority of known Einstein crosses, the background source is a distant quasar — the small and incredibly bright nucleus of an active galaxy. But other sources can be lensed into Einstein crosses as well, under the right circumstances.

 

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Breathtaking new map of the X-ray Universe

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© Jeremy Sanders, Hermann Brunner and the eSASS team (MPE); Eugene Churazov, Marat Gilfanov (on behalf of IKI)

By Jonathan Amos

BBC Science Correspondent

 

Behold the hot, energetic Universe.
A German-Russian space telescope has just acquired a breakthrough map of the sky that traces the heavens in X-rays.
The image records a lot of the violent action in the cosmos - instances where matter is being accelerated, heated and shredded.
Feasting black holes, exploding stars, and searingly hot gas.
The data comes from the eRosita instrument mounted on Spektr-RG.
This orbiting telescope was launched in July last year and despatched to an observing position some 1.5 million km from Earth. Once commissioned and declared fully operational in December, it was left to slowly rotate and scan the depths of space.
eRosita's first all-sky data-set, represented in the image at the top of this page, was completed only last week. It records over a million sources of X-rays.
"That's actually pretty much the same number as had been detected in the whole history of X-ray astronomy going back 60 years. We've basically doubled the known sources in just six months," said Kirpal Nandra, who heads the high-energy astrophysics group at the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany.
"The data is truly stunning and I think what we're doing here will revolutionise X-ray astronomy," he told BBC News.

 

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See also Max-Planck webpage

 

A Milky Way flash implicates magnetars as a source of fast radio bursts

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A bright radio burst generated by a magnetar (one illustrated) in our galaxy hints that similar objects are responsible for at least some of the fast radio bursts in other galaxies, which have puzzled astronomers for over a decade. L. CALÇADA/ESO

High-energy event nearby could help explain mystery signals from distant galaxies

By Maria Temming

Astronomers think they’ve spotted the first example of a superbright blast of radio waves, called a fast radio burst, originating within the Milky Way.

Dozens of these bursts have been sighted in other galaxies — all too far away to see the celestial engines that power them (SN: 2/7/20). But the outburst in our own galaxy, detected simultaneously by two radio arrays on April 28, was close enough to see that it was generated by a highly magnetic neutron star called a magnetar.

That observation is a smoking gun that magnetars are behind at least some of the extragalactic fast radio bursts, or FRBs, that have defied explanation for over a decade (SN: 7/25/14). Researchers describe the magnetar’s radio burst online at arXiv.org on May 20 and May 21.

“When I first heard about it, I thought, ‘No way. Too good to be true,’” says Ben Margalit, an astrophysicist at the University of California, Berkeley, who wasn’t involved in the observations. “Just, wow. It’s really an incredible discovery.”

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You may have a look also in a recent TAT paper  

 

Astronomers find 'missing matter', solving decades-long mystery of outer space

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The Australian Square Kilometre Array Pathfinder helped detect the universe's missing matter.(Supplied: Kirsten Gottschalk, COMET)

28.05.2020

By science, technology and environment reporter Michael Slezak and the Specialist Reporting Team's Penny

 

After an intergalactic search lasting more than two decades, an Australian-led team of scientists say they have finally found the universe's "missing matter", solving a mystery that has long stumped astronomers.

Since the mid-90s, scientists have been trying to locate half of the universe's ordinary matter. They believed it was out there because of clues left over from the Big Bang, but it had never been seen.

"What we're talking about here is what scientists call baryonic matter, which is the normal stuff that you and I are made of," said Associate Professor Jean-Pierre Macquart, from the Curtin University node of the International Centre for Radio Astronomy Research.

Astronomy is full of missing stuff. Most of the universe is understood to be "dark matter" and "dark energy", which nobody has ever directly seen. But even more of a mystery for astronomers was that they couldn't find about half the ordinary matter in the universe.

 

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This is the first fast radio burst known to have a steady beat

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The CHIME radio telescope in British Columbia (pictured) found that a repeating source of radio waves from deep space has a brief window of activity about every 16 days.
CHIME COLLABORATION

By Christopher Crockett
FEBRUARY 7, 2020

A blast of radio waves from deep space appears to be on a 16-day cycle

A periodic flurry of radio waves from some unknown object in deep space could help astronomers figure out what’s triggering similar radio bursts in other galaxies.

Since 2007, researchers have cataloged over 100 fast radio bursts, or FRBs, coming from every direction in the sky. But it’s unknown what causes these radio bursts. Only 10 have been seen to repeat (SN: 8/14/19), and none of those had exhibited any sort of steady tempo — until now.

One of the known repeaters has a relatively brief window of activity about every 16 days, researchers report January 28 at arXiv.org. That means something about the source or its environment is reliably controlling the burst activity, a potential clue to the true nature of these enigmatic objects.

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Virginia Trimble Has Seen the Stars

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Virginia Trimble at the University of California, Irvine, where she has been on the faculty since 1971. (Monica Almeida for Quanta Magazine)

Elizabeth Landau  November 11, 2019

How a young celebrity became one of the first female astronomers at Caltech, befriended Richard Feynman, and ended up the world’s foremost chronicler of the science of the night sky.

Beginning in 1991, Virginia Trimble read every single astronomy article published in 23 different journals. She would then write an annual “year in review” article, which astronomers everywhere used as a window into the rest of the field at large. Her characteristic dry humor came through even in the first installment: “Science, notoriously, progresses amoeba-like, thrusting out pseudopods in unpredictable directions and dragging in the rest of the body after or, occasionally, retreating in disorder.” She stopped in 2007, in part because, with online publishing, there were just too many articles to read.

This endeavor and others have given Trimble a perspective on the past half-century of astronomy that few others could claim.

Stardom was part of Trimble’s early years, and not just because she attended Hollywood High School. In 1962, while still an undergraduate at the University of California, Los Angeles, she achieved her first small measure of fame when Life magazine published an article about her titled “Behind a Lovely Face, a 180 I.Q.” Then in 1963, she became Miss Twilight Zone, the face of a publicity campaign to promote the popular sci-fi show with Rod Serling.

In college she immersed herself in the other kind of stars — the ones in the broader universe — and went on to become one of the first women to earn a doctorate in astrophysics at the California Institute of Technology. While she was there, she befriended Richard Feynman, who paid her $5.50 an hour to pose as a model.

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Dying stars called collapsars may forge much of the universe’s gold

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BLAST FROM COLLAPSE A collapsar occurs when a massive, spinning star collapses into a black hole, powering a blast of light known as a long gamma ray burst (illustrated) and exploding the star’s outer layers.

Spinning stellar objects collapsing into black holes could help explain heavy elements’ origins
BY EMILY CONOVER  MAY 8, 2019

 

The gold in your favorite jewelry could be the messy leftovers from a newborn black hole’s first meal.

Heavy elements such as gold, platinum and uranium might be formed in collapsars — rapidly spinning, massive stars that collapse into black holes as their outer layers explode in a rare type of supernova. A disk of material, swirling around the new black hole as it feeds, can create the conditions necessary for the astronomical alchemy, scientists report online May 8 in Nature.

“Black holes in these extreme environments are fussy eaters,” says astrophysicist Brian Metzger of Columbia University, a coauthor of the study. They can gulp down only so much matter at a time, and what they don’t swallow blows off in a wind that is rich in neutrons — just the right conditions for the creation of heavy elements, computer simulations reveal.

Astronomers have long puzzled over the origins of the heaviest elements in the universe. Lighter elements like carbon, oxygen and iron form inside stars, before being spewed out in stellar explosions called supernovas. But to create elements further down the periodic table, an extreme environment densely packed with neutrons is required. That’s where a chain of reactions known as the r-process can occur, in which atomic nuclei rapidly absorb neutrons and undergo radioactive decay to create new elements.

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Relativistic jet broke through cocoon after neutron star merger

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Artist's impression of a neutron-star merger (Courtesy: NASA)

Physics World

05 Sep 2018

A jet of charged particles moving at nearly the speed of light smashed its way out of debris left behind in the aftermath of the neutron-star merger that produced the gravitational waves detected by the LIGO–Virgo collaboration on 17 August 2017.

The event, catalogued as GW170817, has been a Rosetta Stone for astronomers because it allowed them for to observe the same event using gravitational waves and electromagnetic radiation ranging from a gamma ray burst (GRB) to a radio afterglow. This was a first for the new and exciting field of multimessenger astronomy.

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IceCube Neutrinos Point to Long-Sought Cosmic Ray Accelerator

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In this artistic rendering, a blazar emits both neutrinos and gamma rays that could be detected by the IceCube Neutrino Observatory as well as by other telescopes on Earth and in space. Credit: IceCube/NASA

By the IceCube Collaboration, 12 Jul 2018 10:00 AM

An international team of scientists has found the first evidence of a source of high-energy cosmic neutrinos, ghostly subatomic particles that can travel unhindered for billions of light years from the most extreme environments in the universe to Earth.
The observations, made by the IceCube Neutrino Observatory at the Amundsen–Scott South Pole Station and confirmed by telescopes around the globe and in Earth’s orbit, help resolve a more than a century-old riddle about what sends subatomic particles such as neutrinos and cosmic rays speeding through the universe.

Since they were first detected over one hundred years ago, cosmic rays—highly energetic particles that continuously rain down on Earth from space—have posed an enduring mystery: What creates and launches these particles across such vast distances? Where do they come from?
Because cosmic rays are charged particles, their paths cannot be traced directly back to their sources due to the powerful magnetic fields that fill space and warp their trajectories. But the powerful cosmic accelerators that produce them will also produce neutrinos. Neutrinos are uncharged particles, unaffected by even the most powerful magnetic field. Because they rarely interact with matter and have almost no mass—hence their sobriquet “ghost particle”—neutrinos travel nearly undisturbed from their accelerators, giving scientists an almost direct pointer to their source.

 

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Supermassive black hole seen eating star for the first ever time

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Artist conception of a tidal disruption event (TDE) that happens when a star passes fatally close to a supermassive black hole, which reacts by launching a relativistic jet. (Sophia Dagnello, NRAO/AUI/NSF; NASA, STScI )

Andrew Griffin  15.06.2018


The huge, violent event sees a blast of matter shot across the universe

 

Scientists have seen the vast blast thrown out by a black hole eating a star for the first ever time.

Researchers have finally watched the formation and expansion of the fast-moving jet of material that is thrown out when a supermassive black hole's gravity grabs a star and tears it apart.

Scientists watched the dramatic event using highly specialised telescopes, which are trained on a pair of colliding galaxies called Arp 299, nearly 150 million light-years from Earth. At the centre of one of those galaxies, a star twice the size of the Sun came too close to a black hole that is more than 20 million times big as our Sun – and was shredded apart, throwing a blast across the universe.

 

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First Hours of the GW170817 Kilonova: Why So Blue?

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Artist’s illustration of two merging neutron stars. Astronomers witnessed such a merger in August 2017, and we're now trying to interpret these observations. [University of Warwick/Mark Garlick]

By Susanna Kohler on 13 April 2018

Now that the hubbub of GW170817 — the first coincident detection of gravitational waves and an electromagnetic signature — has died down, scientists are left with the task of taking the spectrum-spanning observations and piecing them together into a coherent picture. Researcher Iair Arcavi examines one particular question: what caused the blue color in the early hours of the neutron-star merger?

 

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Distant galaxy group contradicts common cosmological models, simulations

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Centaurus A, an elliptical galaxy 13 million light-years from Earth, hosts a group of dwarf satellite galaxies co-rotating in a narrow disk, a distribution not predicted by dark-matter-influenced cosmological models. Credit: Christian Wolf and the SkyMapper team / Australian National University

February 1, 2018, University of California, Irvine

An international team of astronomers has determined that Centaurus A, a massive elliptical galaxy 13 million light-years from Earth, is accompanied by a number of dwarf satellite galaxies orbiting the main body in a narrow disk. In a paper published today in Science, the researchers note that this is the first time such a galactic arrangement has been observed outside the Local Group, home to the Milky Way.

"The significance of this finding is that it calls into question the validity of certain cosmological models and simulations as explanations for the distribution of host and satellite galaxies in the universe," said co-author Marcel Pawlowski, a Hubble Fellow in the Department of Physics & Astronomy at the University of California, Irvine.
He said that under the lambda cold dark matter model, smaller systems of stars should be more or less randomly scattered around their anchoring galaxies and should move in all directions. Yet Centaurus A is the third documented example, behind the Milky Way and Andromeda, of a "vast polar structure" in which satellite dwarves co-rotate around a central galactic mass in what Pawlowski calls "preferentially oriented alignment."

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LISA mission passes review successfully and begins next stage of development

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LISA has passed its Mission Definition Review with flying colours

January 22, 2018

Before an ESA mission reaches the launch pad, it has to go through a number of approval procedures that ensure the mission´s readiness. The future space-based gravitational wave observatory, the Laser Interferometer Space Antenna (LISA), has recently passed its Mission Definition Review (MDR) with flying colours.
The MDR's goal is to review and confirm that

  • LISA's present mission design is feasible and suitable,
  • the mission requirements meet LISA´s science requirements,
  • the requirements are mature and adequate to the current phase,
  • the technology developments are adequate to the current phase, and
  • the interfaces between spacecraft, payload ground segment and launcher are well defined.

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The Gaia Mission Could Moonlight as a Gravitational Wave Detector

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In February of 2016, scientists working for the Laser Interferometer Gravitational-Wave Observatory (LIGO) made the first-ever detection of gravitational waves. Since that time, multiple detections have taken place, thanks in large to part to improvements in instruments and greater levels of collaboration between observatories. Looking ahead, its possible that missions not designed for this purpose could also “moonlight” as gravitational wave detectors.

For example, the Gaia spacecraft – which is busy creating the most detailed 3D map of the Milky Way – could also be instrumental when it comes to gravitational wave research. That’s what a team of astronomers from the University of Cambridge recently claimed. According to their study, the Gaia satellite has the necessary sensitivity to study ultra-low frequency gravitational waves that are produced by supermassive black hole mergers.

 

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'Zombie star' amazes astronomers by surviving multiple supernovae

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An artist’s impression of a supernova explosion. Until now, stellar explosions have been considered singular events. Illustration: Courtesy of the European Southern Observatory/M. Kornmesser.

Star has exploded in ‘fatal’ supernovae multiple times since 1954 – and is the first star astronomers have witnessed doing so

Astronomers have spotted a “zombie star” that refused to die when massive explosions that are normally considered fatal rocked the heavenly body.

The star, which lies half a billion light years away in the constellation of the Great Bear, has exploded multiple times since 1954, but may finally be on its way to the cosmic graveyard.

It is the first time astronomers have seen the same star explode over and over. Until now stellar explosions, or supernovae, have been considered singular events, the dazzling death throes of stars that have burned up all their fuel.

 

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Squishy or Solid? A Neutron Star’s Insides Open to Debate

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The core of a neutron star is such an extreme environment that physicists can’t agree on what happens inside. But a new space-based experiment — and a few more colliding neutron stars — should reveal whether neutrons themselves break down.

Joshua Sokol - Contributing Writer - October 30, 2017

The alerts started in the early morning of Aug. 17. Gravitational waves produced by the wreck of two neutron stars — dense cores of dead stars — had washed over Earth. The thousand-plus physicists of the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) rushed to decode the space-time vibrations that rolled across the detectors like a drawn-out peal of thunder. Thousands of astronomers scrambled to witness the afterglow. But officially, all this activity was kept secret. The data had to be collected and analyzed, the papers written. The outside world wouldn’t know for two more months.

The strict ban put Jocelyn Read and Katerina Chatziioannou, two members of the LIGO collaboration, in a bit of an awkward situation. In the afternoon on the 17th, the two were scheduled to lead a panel at a conference dedicated to the question of what happens under the almost unfathomable conditions in a neutron star’s interior. Their panel’s topic? What a neutron-star merger would look like. “We sort of went off at the coffee break and sat around just staring at each other,” said Read, a professor at California State University, Fullerton. “OK, how are we going to do this?”

 

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Chandrasekhar’s role in 20th-century science

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19 Οκτωβρίου 2017  ---  S. Chandrasekhar’s 107th Birthday

Freeman Dyson: Once the astrophysics community had come to grips with a calculation performed by a 19-year-old student sailing off to graduate school, the heavens could never again be seen as a perfect and tranquil dominion.

Physics Today 63, 12, 44 (2010); doi: http://dx.doi.org/10.1063/1.3529001

 

In 1946 Subrahmanyan Chandrasekhar gave a talk at the University of Chicago entitled “The Scientist.” 1 He was then 35 years old, less than halfway through his life and less than a third of the way through his career as a scientist, but already he was reflecting deeply on the meaning and purpose of his work. His talk was one of a series of public lectures organized by Robert Hutchins, then the chancellor of the university. The list of speakers is impressive, and included Frank Lloyd Wright, Arnold Schoenberg, and Marc Chagall. That list proves two things. It shows that Hutchins was an impresario with remarkable powers of persuasion, and that he already recognized Chandra as a world-class artist whose medium happened to be theories of the universe rather than music or paint. I say “Chandra” because that is the name his friends used for him when he was alive.


BASIC SCIENCE AND DERIVED SCIENCE

Chandra began his talk with a description of two kinds of scientific inquiry. “I want to draw your attention to one broad division of the physical sciences which has to be kept in mind, the division into a basic science and a derived science. Basic science seeks to analyze the ultimate constitution of matter and the basic concepts of space and time. Derived science, on the other hand, is concerned with the rational ordering of the multifarious aspects of natural phenomena in terms of the basic concepts.”

 

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COLLIDING NEUTRON STARS

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Artist’s impression of two neutron stars – the compact remnants of what were once massive stars – spiralling towards each other just before merging.

The collision of these dense, compact objects produced gravitational waves – fluctuations in the fabric of spacetime – that were detected by the LIGO/Virgo collaboration on 17 August 2017. A couple of seconds after that, ESA's Integral and NASA’s Fermi satellites detected a burst of gamma rays, the luminous counterpart to the gravitational waves emitted by the cosmic clash.

This is the first discovery of gravitational waves and light coming from the same source.

Full story

 

 

Ultrahigh energy cosmic rays come from outside the Milky Way

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LYING IN WAIT Huge tubs of water (one shown) at the Pierre Auger Observatory in Argentina reveal the tracks left as cosmic particles zip through them.

Huge experiment is trying to track the particles back to their sources
BY LISA GROSSMAN 2:00PM, SEPTEMBER 21, 2017

The largest study yet of the most energetic particles to slam into Earth provides the first solid clues to where the particles come from. Using a giant array of tubs of water, scientists found that these ultrahigh energy cosmic rays mostly originate outside the Milky Way.

An international team analyzed about 12 years of data to show that particles with energies above 8 billion billion electron volts generally come from a particular direction in the sky, and it’s not the galaxy’s center. The researchers report their findings in the Sept. 22 Science.

“It’s the first clear experimental indication that the sources of these high-energy particles are located outside of our own galaxy, probably somewhere in the nearby universe,” says Karl-Heinz Kampert of the University of Wuppertal in Germany, a spokesperson for the Pierre Auger Collaboration, which made the discovery.

 

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NASA to launch first-ever neutron-star mission

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This image shows the configuration of NICER's 56 X-ray mirrors that will gather scientific observations and play an instrumental role in demonstration X-ray navigation. Credit: NASA

 

Nearly 50 years after British astrophysicist Jocelyn Bell discovered the existence of rapidly spinning neutron stars, NASA will launch the world's first mission devoted to studying these unusual objects.

The agency also will use the same platform to carry out the world's first demonstration of X-ray navigation in space.
The agency plans to launch the two-in-one Neutron Star Interior Composition Explorer, or NICER, aboard SpaceX CRS-11, a cargo resupply mission to the International Space Station to be launched aboard a Falcon 9 rocket.
About a week after its installation as an external attached payload, this one-of-a-kind investigation will begin observing neutron stars, the densest objects in the universe. The mission will focus especially on pulsars—those neutron stars that appear to wink on and off because their spin sweeps beams of radiation past us, like a cosmic lighthouse.


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New NASA Mission to Study Mysterious Neutron Stars, Aid in Deep Space Navigation

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May 26, 2017

A new NASA mission is headed for the International Space Station next month to observe one of the strangest observable objects in the universe.

Launching June 1, the Neutron Star Interior Composition Explorer (NICER) will be installed aboard the space station as the first mission dedicated to studying neutron stars, a type of collapsed star that is so dense scientists are unsure how matter behaves deep inside it.

A neutron star begins its life as a star between about seven and 20 times the mass of our sun. When this type of star runs out of fuel, it collapses under its own weight, crushing its core and triggering a supernova explosion. What remains is an ultra-dense sphere only about 12 miles (20 kilometers) across, the size of a city, but with up to twice the mass of our sun squeezed inside. On Earth, one teaspoon of neutron star matter would weigh a billion tons.

 

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Are LIGO’s Black Holes Made From Smaller Black Holes?

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A still image from a simulation that shows a black-hole binary inside a globular cluster. A new study examines how we can tell whether the black holes detected by LIGO were formed hierarchically from mergers of smaller black holes. [Northwestern Visualization/Carl Rodriguez]

By Susanna Kohler on 12 May 2017

 

The recent successes of the Laser Interferometer Gravitational-Wave Observatory (LIGO) has raised hopes that several long-standing questions in black-hole physics will soon be answerable. Besides revealing how the black-hole binary pairs are built, could detections with LIGO also reveal how the black holes themselves form?

 

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5 Reasons Why The 21st Century Will Be The Best One Ever For Astrophysics

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The stars within and beyond the Pillars of Creation are revealed in the infrared. 

Ethan Siegel, Contributor

While Hubble extends its view out to 1.6 microns, more than twice the limit of visible light, James Webb will go out to 30 microns: nearly 20 times as far again.

It's been a staple of science throughout the centuries: the arrogant thinking that we've almost arrived at the ultimate answers to our deepest questions. Scientists thought that Newton's mechanics described everything, until they discovered the wave nature of light. Physicists thought we were almost there when Maxwell unified electromagnetism, and then relativity and quantum mechanics came along. And many thought the nature of matter was complete when we discovered the proton, neutron and electron, until high-energy particle physics revealed an entire Universe of fundamental particles. In just the past 25 years, five incredible discoveries have changed our understanding of the Universe, and each one holds the promise of an even bigger revolution. There's never been a better time to look into the deepest mysteries of existence.

 

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Gravitational waves slow the spin of shape-shifting neutron star

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By Leah Crane

Put on the brakes. A spinning neutron star that shifts between two states slows at a faster rate in one of them – and gravitational waves may be responsible.

The neutron star J1023+0038 spins almost 600 times per second. But as its powerful magnetic field dissipates energy, it is slowing by about 76 rotations per second every billion years. This magnetic “spin-down” is normal, but sometimes J1023 slows at a faster rate.

The different rates are associated with two states the neutron star switches back and forth between: one where it emits mostly radio waves and one where it mainly gives off X-rays. No one knows why some neutron stars behave in this way. But when the star is emitting mostly X-rays, it slows down about 30 per cent faster.

 

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NASA Observes Object Coming Out Of A Blackhole For The First Time Ever

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Commonly held belief and scientific proof holds true that black holes suck matter in rather than spewing them out. But NASA has just found some curious evidence around a supermassive black hole named Markarian 335.

Two of NASA’s telescopes, including the Nuclear Spectroscopic Telescope Array (NuSTAR), observed what is believed to be a black hole’s corona launching away from the supermassive black hole. That event was then followed by a large pulse of X-Ray energy.

 

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Event Horizon Telescope ready to image black hole

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The EHT team has produced simulations of what Einstein's theories predict the hole should look like

Scientists believe they are on the verge of obtaining the first ever picture of a black hole.

By Jonathan Amos
BBC Science Correspondent, Boston


They have built an Earth-sized "virtual telescope" by linking a large array of radio receivers - from the South Pole, to Hawaii, to the Americas and Europe.


There is optimism that observations to be conducted during 5-14 April could finally deliver the long-sought prize.
In the sights of the so-called "Event Horizon Telescope" will be the monster black hole at the centre of our galaxy.
Although never seen directly, this object, catalogued as Sagittarius A*, has been determined to exist from the way it influences the orbits of nearby stars.


These race around a point in space at many thousands of km per second, suggesting the hole likely has a mass of about four million times that of the Sun.


But as colossal as that sounds, the "edge" of the black hole - the horizon inside which an immense gravity field traps all light - may be no more than 20 million km or so across.

 

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Fast radio burst tied to distant dwarf galaxy, and perhaps magnetar

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The dishes of the Karl G. Jansky Very Large Array are seen making thefirst-ever precision localization of a Fast Radio Burst, and therebypointing the way to the host galaxy of FRB121102. Credit: Danielle Futselaar (artsource.nl)

One of the rare and brief bursts of cosmic radio waves that have puzzled astronomers since they were first detected nearly 10 years ago has finally been tied to a source: an older dwarf galaxy more than 3 billion light years from Earth.

Fast radio bursts, which flash for just a few milliseconds, created a stir among astronomers because they seemed to be coming from outside our galaxy, which means they would have to be very powerful to be seen from Earth, and because none of those first observed were ever seen again.

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NASA Telescopes Find Clues For How Giant Black Holes Formed So Quickly

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This illustration represents the best evidence to date that the direct collapse of a gas cloud produced supermassive black holes in the early Universe. Researchers combined data from NASA’s Chandra, Hubble, and Spitzer telescopes to make this discovery.
Credits: NASA/CXC/STScI

Using data from NASA’s Great Observatories, astronomers have found the best evidence yet for cosmic seeds in the early universe that should grow into supermassive black holes.

Researchers combined data from NASA’s Chandra X-ray Observatory, Hubble Space Telescope, and Spitzer Space Telescope to identify these possible black hole seeds. They discuss their findings in a paper that will appear in an upcoming issue of the Monthly Notices of the Royal Astronomical Society.

“Our discovery, if confirmed, explains how these monster black holes were born,” said Fabio Pacucci of Scuola Normale Superiore (SNS) in Pisa, Italy, who led the study. “We found evidence that supermassive black hole seeds can form directly from the collapse of a giant gas cloud, skipping any intermediate steps.”

Scientists believe a supermassive black hole lies in the center of nearly all large galaxies, including our own Milky Way. They have found that some of these supermassive black holes, which contain millions or even billions of times the mass of the sun, formed less than a billion years after the start of the universe in the Big Bang.

 

 

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NASA's Kepler Mission Announces Largest Collection of Planets Ever Discovered

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NASA's Kepler mission has verified 1,284 new planets – the single largest finding of planets to date.

“This announcement more than doubles the number of confirmed planets from Kepler,” said Ellen Stofan, chief scientist at NASA Headquarters in Washington. “This gives us hope that somewhere out there, around a star much like ours, we can eventually discover another Earth.”

Analysis was performed on the Kepler space telescope’s July 2015 planet candidate catalog, which identified 4,302 potential planets. For 1,284 of the candidates, the probability of being a planet is greater than 99 percent – the minimum required to earn the status of “planet.” An additional 1,327 candidates are more likely than not to be actual planets, but they do not meet the 99 percent threshold and will require additional study. The remaining 707 are more likely to be some other astrophysical phenomena. This analysis also validated 984 candidates previously verified by other techniques.

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Astronomers Measure How Fast a Supermassive Black Hole Is Spinning

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To do so, they looked to a second black hole orbiting the first

By Caleb Scharf on May 1, 2016

Black holes may be massive, but they are also extraordinarily compact. That combination of properties makes them challenging regions to evaluate across vast cosmic distances. To learn more about these objects' physical properties, astronomers must therefore come up with measuring tricks. An international team of astronomers recently invented a new one: in the Astrophysical Journal Letters, the members report how to determine a black hole's spin using the interactions of two giant holes bound in mutual orbit.

OJ 287, a binary supermassive black hole system, sits about 3.5 billion light-years from Earth. The duo's primary black hole weighs in at an estimated 18 billion solar masses; the second is a mere 150 million solar masses. Because of this dramatic inequality in size, the smaller hole follows an orbit that punches through a disk of superheated matter swirling around the larger hole. These “outburst” events always occur within a 12-year orbit and are read by astronomers as changes in the system's visible light, which is for the most part produced by the superheated material.

Link of the article : http://arxiv.org/abs/1603.04171

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South African astronomers discover mysterious alignment of black holes

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Findings by University of Cape Town, University of Western Cape offer glimpse of early universe to be revealed when SKA is operational

By Alexis Haden - April 11, 2016

Deep radio imaging by researchers in the University of Cape Town and University of the Western Cape has revealed that supermassive black holes in a region of the distant universe are all spinning out radio jets in the same direction – most likely a result of primordial mass fluctuations in the early universe, a new paper in MNRAS reports today.

The new result is the discovery – for the first time – of an alignment of the jets of radio galaxies over a large volume of space, a finding made possible by a three-year deep radio imaging survey of the radio waves coming from a region called ELAIS-N1 using the Giant Metrewave Radio Telescope (GMRT).

The radio jets are produced by the supermassive black holes at the centres of these galaxies, and the only way for this alignment to exist is if supermassive black holes are all spinning in the same direction, says Prof Andrew Russ Taylor, joint UWC/UCT SKA Chair, Director of the recently-launched Inter-University Institute for Data Intensive Astronomy and principal-author of the study.

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BEHEMOTH BLACK HOLE FOUND IN AN UNLIKELY PLACE [HEIC1607]

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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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Andromeda's first spinning neutron star found

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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 presented in silhouette

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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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Dance of Two Monster Black Holes

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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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Astronomers Observe A Supernova Flash for the First Time Ever

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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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A source accelerating Galactic cosmic rays to unprecedented energy discovered at the centre of the Milky Way

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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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Fresh confusion over origins of enigmatic radio-wave blasts

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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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A repeating fast radio burst (... a young, highly magnetized, extragalactic neutron star)

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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Mysterious radio burst pinpointed in distant galaxy

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The Australia Telescope Compact Array, in New South Wales, which helped to identify the location of a fast radio burst.

For the first time, astronomers have traced an enigmatic blast of radio waves to its source.

Mark Zastrow
24 February 2016 Corrected: 25 February 2016

 

Since 2007, astronomers have detected curious bright blasts of radio waves from the cosmos, each lasting no more than a few milliseconds. Now scientists have been able to pinpoint the source of one of these pulses: a galaxy 1.9 billion parsecs (6 billion light years) away. It probably came from two colliding neutron stars, says astronomer Evan Keane, a project scientist for the Square Kilometre Array (SKA). Keane, who works at the SKA Organization's headquarters at Jodrell Bank Observatory outside Manchester, UK, led the team that reports the detection in Nature1.

The discovery is the “measurement the field has been waiting for”, says astronomer Kiyoshi Masui of the University of British Columbia in Vancouver, Canada. By finding more such fast radio bursts (FRBs) and measuring the distance to their source, astronomers hope to use the signals as beacons to shed light on the evolution of the Universe.

 

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Mysterious radiowave blast may have come from starquake

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                     Jim West/Alamy
The Green Bank Telescope in West Virginia is the third facility to have detected a fast radio burst.

American telescope detects clue to source of fast radio bursts.

Elizabeth Gibney
02 December 2015

 

For the past eight years, astronomers have been mystified by sudden, very short blasts of radio waves that defy explanation.

Now the most detailed study so far1 has furnished a clue to the origin of at least one of these strange pulses, or 'fast radio bursts' (FRBs). It came from a dense, magnetized region of space, and was probably emitted by a young neutron star (a compact core left in the aftermath of a supernova), says study author Kiyoshi Masui at the University of British Columbia in Canada.

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Rapidly spinning stars explain dark matter signal from galactic center

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Gamma ray picture of the Milky Way, as seen by the NASA Fermi satellite. Inserts: two independent statistical analyses showed that the distribution of photons is clumpy rather than smooth, indicating that the excess gamma rays from the center of our galaxy are unlikely to be caused by dark matter annihilation.
Image courtesy of Christoph Weniger, UvA , © UvA/Princeton

The excess of gamma rays from the center of the Milky Way probably originates from rapidly rotating neutron stars and not from dark matter annihilation as previously claimed.

he puzzling excess of gamma rays from the center of the Milky Way probably originates from rapidly rotating neutron stars, or millisecond pulsars, and not from dark matter annihilation, as previously claimed. This is the conclusion of new data analyses by two independent research teams from the University of Amsterdam (UvA), Netherlands, and Princeton University/Massachusetts Institute of Technology (MIT).

In 2009, observations with the Fermi Large Area Telescope revealed an excess of high-energy photons, or gamma rays, at the center of our galaxy. It was long speculated that this gamma ray excess could be a signal of dark matter annihilation. If true, it would constitute a breakthrough in fundamental physics and a major step forward in our understanding of the matter constituents of the universe.

 

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Astronomers find six new millisecond pulsars

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Artist's concept of a millisecond pulsar. Credit: NASA

January 26, 2016 by Tomasz Nowakowski

(Phys.org)—NASA's Fermi Gamma-ray Space Telescope has once again proven that it is an excellent tool to search for rotating neutron stars emitting beams of electromagnetic radiation, known as pulsars. A team of astronomers, led by H. Thankful Cromartie of the University of Virginia, has recently used the 305-meter Arecibo radio telescope in Puerto Rico to observe unidentified sources of gamma rays detected by the Large Area Telescope (LAT) onboard the Fermi spacecraft. As it turns out, six of these objects indicated by LAT are rapidly rotating neutron stars, with periods of a few thousandths of a second, called millisecond pulsars (MSPs). The scientists published their results online on Jan. 20 on the arXiv pre-print server.

The objects of the study were chosen from the LAT's 4-year point source catalog. The astronomers chose 34 from over 1,000 unidentified sources of gamma rays to observe them in detail with the Arecibo telescope. The catalog provided crucial spectral data that helped distinguish possible MSPs from other gamma-ray-emitting objects, like active galactic nuclei (AGNs).

"Overall, the search for MSPs in the galactic disk has been made extremely efficient by employing Fermi-LAT data in selecting radio search targets," the researchers noted in their paper posted on arXiv.

Arecibo observations were conducted from June to September 2013. The telescope's raw sensitivity and its large gain makes it a very efficient tool for finding millisecond pulsars. Thanks to Arecibo, the researchers were able to detect six MSPs with rotation periods ranging between 1.99 and 4.66 ms. One of the newly detected pulsars is a typical neutron star, a white dwarf binary with an 83-day orbital period. According to the research, the other MSPs are in interacting compact binaries wit orbital period less than eight hours.

 

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...decisive evidence for the magnetic structure of matter

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Recent discoveries provided more decisive evidence for the magnetic structure of matter

Posted by The Watcher on January 24, 2016

 

Since the beginning of the space age, many observations sharply contradict the theories of a gravity-dominated Cosmos, yet recent observations have created even larger holes in those theories. Now it is impossible to cover these holes with any theoretical solution, such as the so-called red giants.

According to the consensus model, a star becomes a red giant in the later part of its life. In this stage, most of the fuel powering nuclear fusion in the core of the star is exhausted. As a result of this deficiency, "gravitational collapse" is induced. In other words, the star would collapse on itself due to a lack of light pressure which is pushing out against the force of gravity.

When this self-collapse takes place, it heats up a shell of hydrogen that surrounds the core. That heat would be sufficient to reignite fusion reaction, causing the star to become bigger as a result of increased light pressure and this process would make the star 1 000-10 000 times more luminous.

 

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Universe’s most luminous supernova was 50 times brighter than the Milky Way

undefinedThe artist’s impression above shows what it would look like from an exoplanet 10,000 light-years away in its home galaxy.


By Daniel Clery

Jan. 14, 2016


Kaboom! Astronomers have found the most violently explosive supernova so far detected in the history of the universe. Supernovae are already some of the brightest events out there but in recent decades astronomers have seen a rare new class of blasts, superluminous supernovae (SLSNe)—sometimes dubbed hypernovae. The new discovery was spotted last June by the All Sky Automated Survey for SuperNovae (ASAS-SN), a system of eight small 14-centimeter telescopes at two sites in Chile and Hawaii that can scan the entire sky every 2 to 3 days. At its peak, ASAS-SN-15lh, as the new supernova is known, was twice as luminous as any previously seen, thousands of times brighter than a normal supernova, and outshone our entire Milky Way galaxy by 50 times. 

 

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Hubble sees multiple images of a supernova for the very first time

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5 March 2015

Astronomers using the NASA/ESA Hubble Space Telescope have, for the first time, spotted four images of a distant exploding star. The images are arranged in a cross-shaped pattern by the powerful gravity of a foreground galaxy embedded in a massive cluster of galaxies. The supernova discovery paper will appear on 6 March 2015 in a special issue of Science celebrating the centenary of Albert Einstein’s theory of general relativity.

 

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Einstein@Home Finds an Elusive Pulsar

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Fermi-LAT sky map with the celestial neighborhood of the newly discovered pulsar PSR J1906+0722. The color scale shows the gamma-ray intensity. [Knispel/AEI/NASA/DOE/Fermi LAT Collaboration]

Since the release of the second Fermi-LAT catalog in 2012, astronomers have been hunting for 3FGL J1906.6+0720, a gamma-ray source whose association couldn’t be identified. Now, personal-computer time volunteered through the Einstein@Home project has resulted in the discovery of a pulsar that has been hiding from observers for years.

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Smallest Black Hole in Galactic Nucleus Detected

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Smoothed SDSS image of RGG 118, home of the smallest black hole ever observed in a galactic nucleus. The inset shows the Chandra identification of an x-ray source at the center. Credit: Baldassare et al. 2015
A team of astronomers have reported the detection of the smallest black hole (BH) ever observed in a galactic nucleus. The BH is hosted in the center of dwarf galaxy RGG 118, and it weighs in at 50,000 solar masses, according to observations made by Vivienne Baldassare of University of Michigan and her collaborators.

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Energy Boost from Black Holes

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Particle swarm. In Schnittman’s simulation, dark matter particles (shown with gray and pink trails) orbiting a rotating black hole (central sphere) could occasionally gain a large amount of energy and escape. The blue region (the ergosphere) is where the black hole’s rotation pulls spacetime along.

Particles orbiting near a spinning black hole might collide and get ejected with much more energy than previous calculations showed.

 

Black holes are mostly takers, not givers, but collisions among matter around a spinning black hole can result in high-energy particles that emerge with some of the black hole’s energy. Decades-old calculations showing only a modest energy gain for such particles are now contradicted by new results from two theoretical efforts showing that a particle can take away more than 10 times the energy that was put in. There are still questions about the feasibility of such collisions, but they might help astrophysicists understand some unexplained observations, such as an excess of gamma rays from the galactic center or ultrahigh-energy cosmic rays.

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Spectacular Einstein Ring --"Reveals Secrets of the Early Universe"

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Einstein Rings are more than just an incredible novelty. It’s also a very rare phenomenon that can offer insights into dark matter, dark energy, the nature of distant galaxies, and the curvature of the Universe itself. The phenomenon, called gravitational lensing, occurs when a massive galaxy in the foreground bends the light rays from a distant galaxy behind it, in much the same way as a magnifying glass would. When both galaxies are perfectly lined up, the light forms a circle, called an “Einstein ring”, around the foreground galaxy. If another more distant galaxy lies precisely on the same sightline, a second, larger ring will appear.

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PARANAL and LA PALMA sites chosen for final negotiations to host World's largest array of Gamma Ray Telescopes

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Zeuthen, Germany – On 15 and 16 July 2015, the Cherenkov Telescope Array (CTA) Resource Board decided to enter into detailed contract negotiations for hosting CTA on the European Southern Observatory (ESO) Paranal grounds in Chile and at the Instituto de Astrofisica de Canarias (IAC), Roque de los Muchachos Observatory in La Palma, Spain.

The Board, composed of representatives of ministries and funding agencies from Austria, Brazil, the Czech Republic, France, Germany, Italy, Namibia, the Netherlands, Japan, Poland, South Africa, Spain, Switzerland and the UK, decided after months of negotiations and careful consideration of extensive studies of the environmental conditions, simulations of the science performance and assessments of construction and operation costs to start contract negotiations with ESO and Spain. The Namibian and Mexican sites will be kept as viable alternatives.

 

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Chandra finds evidence for serial black hole eruptions

 

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The supermassive black hole in NGC 5813 has erupted at least three times, with the latest still occurring.

Chandra data show the supermassive black hole at the center of NGC 5813 has erupted multiple times over 50 million years. NGC 5813 is the central component of a group of galaxies called the NGC 5813 Group that is immersed in an enormous reservoir of hot gas.

 Scientists discovered this history of black hole eruptions by studying the NGC 5813 Group, a group of galaxies about 105 million light-years from Earth. These Chandra observations are the longest ever obtained of a galaxy group, lasting for just over a week. The Chandra data are shown in this new composite image where the X-rays from Chandra (purple) have been combined with visible-light data (red, green, and blue).

Galaxy groups are like their larger cousins, galaxy clusters, but instead of containing hundreds or even thousands of galaxies like clusters do, galaxy groups are typically composed of 50 or fewer galaxies. Like galaxy clusters, groups of galaxies are enveloped by giant amounts of hot gas that emit X-rays.

The erupting supermassive black hole is located in the central galaxy of the NGC 5813 Group. The black hole’s spin, coupled with gas spiraling toward the black hole, can produce a rotating, tightly wound vertical tower of magnetic field that flings a large fraction of the inflowing gas away from the vicinity of the black hole in an energetic high-speed jet.

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ALMA’s observation of Einstein Ring reveals extraordinary detail

Sharpest View Ever of Star Formation in the Distant Universe

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ALMA’s Long Baseline Campaign has produced a spectacular image of a distant galaxy being gravitationally lensed. The image shows a magnified view of the galaxy’s star-forming regions, the likes of which have never been seen before at this level of detail in a galaxy so remote. The new observations are far sharper than those made using the NASA/ESA Hubble Space Telescope, and reveal star-forming clumps in the galaxy equivalent to giant versions of the Orion Nebula in the Milky Way.

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Technology from ‘Interstellar’ Could Be Useful to Scientists, Too

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Black holes create and destroy galaxies, like this spiral galaxy in the constellation Dorado. (Roberto Colombari/Stocktrek Images/Corbis)

Much has been made of the mind-bending visual effects in Interstellar. But the methods created by the film’s Oscar-nominated visual effects team may have more serious applications than wowing movie audiences—they could actually be useful to scientists, too. A new paper in Classical and Quantum Gravity tells how the Interstellar team turned science fiction towards the service of scientific fact and produced a whole new picture of what it might look like to orbit around a spinning black hole.

Director Christopher Nolan and executive producer (and theoretical physicist) Kip Thorne wanted to create a visual experience that was immersive and credible. When they began to construct images of a black hole within an accretion disk, they realized that existing visual effects technology wouldn’t cut it—it created a flickering effect that would have looked bad in IMAX theaters. So the team turned to physics to create something different.

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Foamy Evidence

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Modern cosmology is dominated by two fundamental theories: general relativity, which describes the structure of space and time as manifold that interacts with mass/energy (aka gravity), and quantum theory, which describes the fundamental interactions of protons, electrons, light, etc. (aka quanta). Both models are strongly supported by experimental and observational evidence. The problem is that each theory makes fundamental assumptions about the way the universe works, and they contradict each other at a basic level. This isn’t a problem if you are interested in things on a large scale, such as planets and galaxies (general relativity), or things on a small scale such as nuclear fusion (quantum theory). The contradiction arises when you want to understand objects that are both very dense and interact at high energies, such as black hole interiors, the big bang, etc. So one of the challenges of modern cosmology is to develop a unified theory of quantum gravity, which would combine the predictions of general relativity and quantum theory in a consistent way.

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