The Aftermath of Neutron Star Mergers

An artistic rendering of two neutron stars merging. Credit: NSF/LIGO/Sonoma State/A. Simonnet

Neutron stars (NS) are the collapsed cores of supermassive giant stars that contain between 10 and 25 solar masses. Aside from black holes, they are the densest objects in the Universe. Their journey from a main sequence star to a collapsed stellar remnant is a fascinating scientific story.

Sometimes, a binary pair of NS will merge, and what happens then is equally as fascinating.

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The Cosmic Neutrino Background Would Tell Us Plenty About the Universe

Readers of Universe Today are probably already familiar with the concept of the Cosmic Microwave Background (CMB). Its serendipitous discovery by a pair of radio astronomers at Bell Labs is the stuff of astronomical legend. Over the past decades, it has offered plenty of insights into the Big Bang and the origins of our universe. But there is another, less well-known background signal that could be just as revolutionary – or at least we think there is. The Cosmic Neutrino Background (CvB) has been posited for years but has yet to be found, primarily because neutrinos are notoriously difficult to detect. Now, a paper from Professor Douglas Scott of the University of British Columbia, developed as part of a summer school on neutrinos held by the International School of AstroParticle Physics in the Italian town of Varenna, discusses what we could potentially learn if we do manage to detect the CvB eventually.

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Scientists are Recommending IceCube Should be Eight Times Bigger

This image shows a visual representation of one of the highest-energy neutrino detections superimposed on a view of the IceCube Lab at the South Pole. Credit: IceCube Collaboration
This image shows a visual representation of one of the highest-energy neutrino detections superimposed on a view of the IceCube Lab at the South Pole. Credit: IceCube Collaboration

The IceCube Neutrino Observatory, operated by the University of Wisconsin-Madison (UW-M), located at the Amundsen–Scott South Pole Station in Antarctica, is one of the most ambitious neutrino observatories in the world. Behind this observatory is the IceCube Collaboration, an international group of 300 physicists from 59 institutions in 14 countries. Relying on a cubic kilometer of ice to shield from external interference, this observatory is dedicated to the search for neutrinos. These nearly massless subatomic particles are among the most abundant in the Universe and constantly pass through normal matter.

By studying these particles, scientists hope to gain insight into some of the most violent astrophysical sources – such as supernovae, gamma-ray bursts, merging black holes and neutron stars, etc. The group of scientists tasked with advising the U.S. government on particle physics research is known as the Particle Physics Project Prioritization Panel (P5). In a recent draft report, “Pathways to Innovation and Discovery in Particle Physics,” the P5 team recommended a planned expansion of IceCube. This recommendation is one of several that define the future of astrophysics and particle physics research.

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When Stars Consume Their Partners, We Could Detect a Blast of Neutrinos

Three thousand light-years away, the Cat's Eye Nebula, a dying star throws off shells of glowing gas. This image from the Hubble Space Telescope reveals the nebula to be one of the most complex planetary nebulae known.The features seen in the Cat's Eye are so complex that astronomers suspect the central object may actually be a binary star system.
The Cat's Eye Nebula (NGC6543) is thought to be caused by a binary star system. Credit - NASA/HST

You might be familiar with the bizarre ritual of the female praying mantis which, I’m told, bites off the head and eats other body parts of the poor male they just mated with. It seems consuming partners is not unheard of.  It’s even seen in the lives of stars where binary stars orbit one another closely and one star ultimately consumes the other. If the victim is a neutron star a burst of neutrinos can be generated and a new study reveals they might just be detectable on Earth. 

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IceCube Makes a Neutrino Map of the Milky Way

An artist’s concept of the Milky Way seen through a neutrino lens (blue). Credit: IceCube Collaboration/U.S. National Science Foundation (Lily Le & Shawn Johnson)/ESO (S. Brunier)
An artist’s concept of the Milky Way seen through a neutrino lens (blue). Credit: IceCube Collaboration/U.S. National Science Foundation (Lily Le & Shawn Johnson)/ESO (S. Brunier)

We’ve seen the Milky Way with ultraviolet eyes, through x-ray vision, gamma-ray views, radio emissions, microwaves, and visible light. Now, consider a neutrino point of view. Thanks to the IceCube Collaboration, we get to see our home galaxy through the lens of this mysterious particle. It’s an eerie sight that also tells us our galaxy isn’t quite like the others. It’s a neutrino desert.

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Plans are Underway to Build a 30 Cubic Kilometer Neutrino Telescope

Underwater neutrino detectors take advantage of location to track these fast particles. This is an artist's impression of a KM3NeT installation in the Mediterranean. Chinese scientists hope to build a bigger underwater "neutrino telescope" in the next few years. Courtesy Edward Berbee/Nikhef.
Underwater neutrino detectors take advantage of location to track these fast particles. This is an artist's impression of a KM3NeT installation in the Mediterranean. Chinese scientists hope to build a bigger underwater "neutrino telescope" in the next few years. Courtesy Edward Berbee/Nikhef.

How do astronomers look for neutrinos? These small, massless particles whiz through the universe at very close to the speed of light. They’ve been studied since the 1950s and detecting them provides work for a range of very interesting observatories.

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IceCube Senses Neutrinos Streaming From an Active Galaxy 47 Million Light-Years Away

This is a Hubble Space Telescope image of the Messier 77 spiral galaxy. Scientists working with the IceCube Neutrino Observatory detected neutrinos emanating from the galaxy's core. Image Credit: By NASA, ESA & A. van der Hoeven - http://www.spacetelescope.org/news/heic1305/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=25328266

Researchers using the IceCube Neutrino Observatory have detected neutrinos emanating from the energetic core of an active galaxy millions of light-years away. Neutrinos are difficult to detect, and finding them originating from the galaxy is a significant development. What does the discovery mean?

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We Finally Know Where the Highest Energy Cosmic Rays are Coming From: Blazars

blazar

Way out there in space is a class of objects called blazars. Think of them as extreme particle accelerators, able to marshall energies a million times stronger than the Large Hadron Collider in Switzerland. It turns out they’re the culprits in one of the great astrophysical mysteries: what creates and propels neutrinos across the universe at blazingly fast speeds? It turns out that the answer’s been there all along: blazars pump out neutrinos and cosmic rays. That’s the conclusion a group of astronomers led by Dr. Sara Buson of Universität Wurzburg in Germany came to as they studied data from a very unique facility here on Earth: the IceCube Neutrino Observatory in Antarctica.

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A Mission Concept to fly a Solar Neutrino Detector Close to the Sun

This is one of the new images of the Sun from the ESA's Solar Orbiter's closest approach on March 26th, 2022. Image Credit: ESA

Astronomers have proposed a concept mission to fly a neutrino observatory into orbit around the Sun to get a better picture of what’s happening in the Sun’s core.

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Experiment Finds no Sign of Sterile Neutrinos

Could sterile neutrinos be a fourth kind of neutrino? Credit: IceCube - University of Wisconsin

We don’t know what dark matter is. We do know the characteristics of dark matter, and much of how it behaves, so we know what physical properties dark matter must have, but no known matter has all the necessary characteristics of dark matter. So we’re stumped.

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