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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Emanuele Berti has received the 2023 Richard A. Isaacson Award in Gravitational-Wave Science

 

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Richard A. Isaacson Award in Gravitational-Wave Science

 

This award recognizes outstanding contributions in gravitational-wave physics, gravitational-wave astrophysics, and the technologies that enable this science.

The annual award consists of $5,000, a certificate, travel reimbursement and a registration waiver to attend the APS April Meeting to give an invited talk and accept the award.

 

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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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Astronomers reveal first image of the black hole at the heart of our galaxy

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First image of the black hole at the center of the Milky Way. This is the first image of Sagittarius A* (or Sgr A* for short), the supermassive black hole at the centre of our galaxy. It’s the first direct visual evidence of the presence of this black hole. It was captured by the Event Horizon Telescope (EHT), an array which linked together eight existing radio observatories across the planet to form a single “Earth-sized” virtual telescope. The telescope is named after the “event horizon”, the boundary of the black hole beyond which no light can escape. Although we cannot see the event horizon itself, because it cannot emit light, glowing gas orbiting around the black hole reveals a telltale signature: a dark central region (called a “shadow”) surrounded by a bright ring-like structure. The new view captures light bent by the powerful gravity of the black hole, which is four million times more massive than our Sun. The image of the Sgr A* black hole is an average of the different images the EHT Collaboration has extracted from its 2017 observations. Credit: EHT Collaboration

by Amy C. Oliver, National Radio Astronomy Observatory

MAY 12, 2022

 

At simultaneous press conferences around the world, including at a National Science Foundation-sponsored press conference at the U.S. National Press Club in Washington, D.C., astronomers have unveiled the first image of the supermassive black hole at the center of our own Milky Way galaxy. This result provides overwhelming evidence that the object is indeed a black hole and yields valuable clues about the workings of such giants, which are thought to reside at the center of most galaxies. The image was produced by a global research team called the Event Horizon Telescope (EHT) Collaboration, using observations from a worldwide network of radio telescopes.

 

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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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Ultrastrong magnetic fields could prevent neutron stars from forming black holes

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Biggish bang Artist's impression of neutron stars merging, producing gravitational waves and resulting in a kilonova explosion. (Courtesy: University of Warwick/Mark Garlick/CC BY 4.0)

05 Apr 2022

A massive and exotic type of neutron star could be formed by the merger of two neutron stars and avoid becoming a black hole – at least temporarily. That is the conclusion of Arthur Suvorov at Manly Astrophysics in Australia and Kostas Glampedakis at Germany’s University of Tübingen who have calculated that magnetically supramassive neutron stars could stave off gravitational collapse, despite lying above the theoretical mass limit for black hole formation.

In 2017 the LIGO–Virgo collaboration detected the first gravitational waves emanating from two neutron stars as they spiralled into each other, and eventually merged. This event provided important opportunities for astronomers to study the aftermath of the merger using a range of different telescopes, but key questions remain about the object that was created.

 

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10 new gravitational waves found in LIGO-Virgo’s O3a data - The finding hints at exotic black hole behaviors

 

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Space.com

NEWS RELEASE 7-APR-2022

AMERICAN PHYSICAL SOCIETY

In the last seven years, scientists at the LIGO-Virgo Collaboration (LVC) have detected 90 gravitational waves signals. Gravitational waves are perturbations in the fabric of spacetime that race outwards from cataclysmic events like the merger of binary black holes (BBH). In observations from the first half of the most recent experimental run, which continued for six months in 2019, the collaboration reported signals from 44 BBH events.

But outliers were hiding in the data. Expanding the search, an international group of astrophysicists re-examined the data and found 10 additional black hole mergers, all outside the detection threshold of the LVC’s original analysis. The new mergers hint at exotic astrophysical scenarios that, for now, are only possible to study using gravitational wave astronomy.

“With gravitational waves, we’re now starting to observe the wide variety of black holes that have merged over the last few billion years,” says Physicist Seth Olsen, a Ph.D. candidate at Princeton University who led the new analysis. Every observation contributes to our understanding of how black holes form and evolve, he says, and the key to recognizing them is to find efficient ways to separate the signals from the noise.

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Dutch government embraces plans for Einstein Telescope in Limburg region

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14 April 2022

The Dutch government intends to conditionally allocate 42 million euros from the Dutch National Growth Fund to the Einstein Telescope, and is also reserving 870 million euros for a future Dutch contribution to the construction. This decision was taken by the Cabinet based on the advice of the Advisory Committee of the National Growth Fund. With this decision, the Cabinet gives an enormous boost to Dutch science and to the broad development of the South Limburg border region.

The intended investment of 42 million euros will go towards preparatory work such as innovation of the necessary technology, location research, building up a high-tech ecosystem and organisation. With the reservation of the 870 million, the Netherlands has an excellent basis to apply in the future, together with Belgium and Germany, for the realisation of the Einstein Telescope in the border region of South Limburg.

 

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Astronomers close in on new way to detect gravitational waves

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Supermassive black holes orbiting each other very closely are expected to produce gravitational waves.Credit: NASA’s Goddard Space Flight Center/Science Photo Library

Davide Castelvecchi -  Nature

27.1.2022

Astronomers could be on the verge of detecting gravitational waves from distant supermassive black holes — millions or even billions of times larger than the black holes spotted so far — an international collaboration suggests. The latest results from several research teams suggest they are closing in on a discovery after two decades of efforts to sense the ripples in space-time through their effects on pulsars, rapidly spinning spent stars that are sprinkled across the Milky Way.

Gravitational-wave hunters are looking for fluctuations in the signals from pulsars that would reveal how Earth bobs in a sea of gravitational waves. Like chaotic ripples in water, these waves could be due to the combined effects of perhaps hundreds of pairs of black holes, each lying at the centre of a distant galaxy.

So far, the International Pulsar Timing Array (IPTA) collaboration has found no conclusive evidence of these gravitational waves. But its latest analysis — using pooled data from collaborations based in North America, Europe and Australia — reveals a form of ‘red noise’ that has the features researchers expected to see. The findings were published on 19 January in Monthly Notices of the Royal Astronomical Society [1].

 

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A Highly Eccentric Black Hole Merger Detected for the First Time

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Credit RIT

Matt Williams  - Universe Today

3.2.2022

In February 2016, scientists with the Laser Interferometer Gravitational-Wave Observatory (LIGO) confirmed the first-ever detection of a gravitational wave event. Originally predicted by Einstein’s Theory of General Relativity, GWs result from mergers between massive objects – like black holes, neutron stars, and supermassive black holes (SMBHs). Since 2016, dozens of events have been confirmed, opening a new window to the Universe and leading to a revolution in astronomy and cosmology.

In another first, a team of scientists led by the Center for Computational Relativity and Gravitation (CCRG) announced that they may have detected a merger of two black holes with eccentric orbits for the first time. According to the team’s paper, which recently appeared in Nature Astronomy, this potential discovery could explain why some of the black hole mergers detected by the LIGO Scientific Collaboration and the Virgo Collaboration are much heavier than previously expected.

The team consisted of astrophysicists from the CCRG Rochester Institute of Technology, the Institute of Computational and Experimental Research in Mathematics (ICERM) at Brown University, and the University of Florida. As they indicate in their paper, the team took a fresh look at previous findings made in 2020, where they were part of the team that observed the most massive GW binary detected to date (GW190521). This consisted of two black holes that were about 85 and 66 Solar masses, respectively. This resulted in the formation of a black hole remnant of 142 solar masses.

 

 

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ArXiv.org Reaches a Milestone and a Reckoning

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Runaway success and underfunding have led to growing pains for the preprint server

By Daniel Garisto on January 10, 2022

What started in 1989 as an e-mail list for a few dozen string theorists has now grown to a collection of more than two million papers—and the central hub for physicists, astronomers, computer scientists, mathematicians and other researchers. On January 3 the preprint server arXiv.org crossed the milestone with a numerical analysis paper entitled “Affine Iterations and Wrapping Effect: Various Approaches.” (The Library of Alexandria, for comparison, is believed to have contained no more than hundreds of thousands of manuscripts.)
“We’re a way for authors to communicate their research results quickly and freely,” says Steinn Sigurdsson, a professor of astrophysics at Pennsylvania State University and arXiv’s scientific director. Unlike traditional scientific journals, arXiv (pronounced “archive” because the “X” represents the Greek letter chi) allows scientists to share research before it has been peer-reviewed.

 

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What's It Like When You Fall Into A Black Hole?

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From outside a black hole, all the infalling matter will emit light and always is visible, while... [+] ANDREW HAMILTON, JILA, UNIVERSITY OF COLORADO

Ethan Siegel   Jun 1, 2019,

There are many terrifying ways that the Universe can destroy something. In space, if you tried to hold your breath, your lungs would explode; if you exhaled every molecule of air instead, you'd black out within seconds. In some locations, you'd freeze solid as the heat was sucked out of your body; in others it's so hot that your atoms would turn into a plasma. But of all the ways the Universe has to dispose of someone, I can think of none more fascinating than to send someone inside a black hole. So does Event Horizon Telescope scientist Heino Falcke, who asks:

[W]hat is it like to be/fall inside a rotating black hole? This is not observable, but calculable... I have talked with various people who have done these calculations, but I am getting old and keep forgetting things.

It's a tremendously interesting question, and one that science can answer. Let's find out.

According to our theory of gravity, Einstein's General Relativity, there are only three things that determine the properties of a black hole. They are the following:

 

 

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Why extraterrestrial intelligence is more likely to be artificial than biological

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November 28, 2021

Whether extraterrestrial life exists or whether intelligent extraterrestrial life exists aren't the same question. Finding the former is, of course, more likely than finding the latter. We are simultaneously looking for both, but both require an entirely different approach.

When it comes to the search for extraterrestrial intelligence, SETI (which literally stands for Search for ExtraTerrestrial Intelligence) contains a comprehensive variety of efforts.

During the early beginnings in the late 1800s, we first started looking for signs of extraterrestrial intelligence within our own solar system. In modern times, however, most of the global effort goes to monitoring electromagnetic radiation to detect potential transmissions.

A more recent niche avenue in the search takes aim at technosignatures (where scientists look for signs of megastructures like space mirrors and Dyson spheres). At the very cutting edge in the search, we find interstellar quantum communications. Scientists have only recently started thinking of concrete ways of how to search for this kind of transmission.

But if we are to actually discover extraterrestrial life, what do scientists expect to find? According to cosmologist Martin Rees, we aren't likely to find the classic aliens as commonly portrayed in sci-fi movies; he thinks it is far likely that we will stumble upon something else.

In this article, Rees explains why he expects that the bulk of civilizations out there would probably be artificial. Enjoy!

By Martin Rees - Emeritus Professor of Cosmology and Astrophysics, University of Cambridge

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