Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: cosmology – Page 93

Searching for Axions in Polarized Gas

The standard model of fundamental particles and interactions has now been in place for about a half-century. It has successfully passed experimental test after experimental test at particle accelerators. However, many of the model’s features are poorly understood, and it is now clear that standard-model particles only compose about 5% of the observed energy density of the Universe. This situation naturally encourages researchers to look for new particles and interactions that fall outside this model. One way to perform this search is to prepare a gas of polarized atoms and to look for changes in this polarization that might come from new physics. Haowen Su from the University of Science and Technology of China and colleagues have used two separated samples of polarized xenon gas to probe spin-dependent interactions [1] (Fig. 1). The results place constraints on axions—a candidate for dark matter—in a theoretically favored mass range called the axion window.

Searches for new spin-dependent interactions have exploded over the past decade. Special relativity and quantum mechanics tightly constrain the mathematical form for such interactions, with the main adjustable parameters being the coupling strength and the spatial range. Since the form of these interactions is generic across many models, it is possible to conduct experimental searches for new interaction signatures, even in the absence of a specific theory for beyond-standard-model physics.

‘Giant Arc’ Stretching 3.3 Billion Light-years Across The Cosmos Shouldn’t Exist

A newly discovered crescent of galaxies spanning 3.3 billion light-years is one of the world’s largest known structures, challenging some of astronomers’ most fundamental assumptions about the universe.

The epic arrangement known as the Giant Arc is made up of galaxies, galaxy clusters, and a lot of gas and dust. It is located 9.2 billion light-years away and stretches across roughly a 15th of the observable universe.

Its discovery was “serendipitous,” according to Alexia Lopez, a doctoral candidate in cosmology at the University of Central Lancashire (UCLan) in the United Kingdom. Lopez was creating maps of things in the night sky using light from approximately 120,000 quasars, which are distant brilliant cores of galaxies where supermassive black holes consume material and produce energy.

Observations from JWST and Chandra reveal a low-mass supermassive black hole that appears to be consuming matter at over 40 times the theoretical limit

Using data from NASA’s JWST and Chandra X-ray Observatory, a team of U.S. National Science Foundation NOIRLab astronomers have discovered a supermassive black hole at the center of a galaxy just 1.5 billion years after the Big Bang that is consuming matter at a phenomenal rate — over 40 times the theoretical limit. While short lived, this black hole’s ‘feast’ could help astronomers explain how supermassive black holes grew so quickly in the early Universe.

Supermassive black holes exist at the center of most galaxies, and modern telescopes continue to observe them at surprisingly early times in the Universe’s evolution. It’s difficult to understand how these black holes were able to grow so big so rapidly. But with the discovery of a low-mass supermassive black hole feasting on material at an extreme rate, seen just 1.5 billion years after the Big Bang, astronomers now have valuable new insights into the mechanisms of rapidly growing black holes in the early Universe.

LID-568 was discovered by a cross-institutional team of astronomers led by International Gemini Observatory/NSF NOIRLab astronomer Hyewon Suh. They used the James Webb Space Telescope (JWST) to observe a sample of galaxies from the Chandra X-ray Observatory’s COSMOS legacy survey. This population of galaxies is very bright in the X-ray part of the spectrum, but are invisible in the optical and near-infrared. JWST’s unique infrared sensitivity allows it to detect these faint counterpart emissions.

Axion clouds around neutron stars could reveal dark matter origins

Hypothetical particles called axions could form dense clouds around neutron stars – and if they do, they will give off signals that radio telescopes can detect, say researchers in the Netherlands, the UK and the US. Since axions are a possible candidate for the mysterious substance known as dark matter, this finding could bring us closer to understanding it.

Around 85% of the universe’s mass consists of matter that appears “dark” to us. We can observe its gravitational effect on structures such as galaxies, but we cannot observe it directly. This is because dark matter hardly interacts with anything as far as we know, making it very difficult to detect. So far, searches for dark matter on Earth and in space have found no evidence for any of the various dark matter candidates.

\r \r

Hawking radiation may unveil hidden physics in black hole explosions

Detecting exploding primordial black holes from the universe’s first second may unveil new physics.

In that moment, pockets of hot material may have been dense enough to form black holes, potentially with masses ranging from 100,000 times less than a paperclip to 100,000 times more than the sun’s, according to scientists.

Then, as the universe quickly expanded and cooled, the conditions for forming black holes this way ended.

Scientists are now claiming that PBHs may be heating up and exploding throughout the universe.

Physicists discover first “black hole triple”

In a recent discovery, astronomers have found that the black hole in the well-known low-mass X-ray binary (LMXB) system V404 Cygni is part of a much larger structure—a wide triple system.

Many black holes detected to date appear to be part of a pair. These binary systems comprise a black hole and a secondary object — such as a star, a much denser neutron star, or another black hole — that spiral around each other, drawn together by the black hole’s gravity to form a tight orbital pair.

Now a surprising discovery is expanding the picture of black holes, the objects they can host, and the way they form.

In a study appearing today in Nature, physicists at MIT and Caltech report that they have observed a “black hole triple” for the first time. The new system holds a central black hole in the act of consuming a small star that’s spiraling in very close to the black hole, every 6.5 days — a configuration similar to most binary systems. But surprisingly, a second star appears to also be circling the black hole, though at a much greater distance. The physicists estimate this far-off companion is orbiting the black hole every 70,000 years.

/* */