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Category: cosmology – Page 133

New findings from JWST: How black holes switched from creating to quenching stars

Astronomers have long sought to understand the early universe, and thanks to the James Webb Space Telescope (JWST), a critical piece of the puzzle has emerged. The telescope’s infrared detecting “eyes” have spotted an array of small, red dots, identified as some of the earliest galaxies formed in the universe.

This surprising discovery is not just a visual marvel, it’s a clue that could unlock the secrets of how galaxies and their enigmatic black holes began their cosmic journey.

“The astonishing discovery from James Webb is that not only does the universe have these very compact and infrared bright objects, but they’re probably regions where huge black holes already exist,” explains JILA Fellow and University of Colorado Boulder astrophysics professor Mitch Begelman. “That was thought to be impossible.”

Scientists use AI to investigate structure and long-term behavior of galaxies

Bayreuth scientists are investigating the structure and long-term behavior of galaxies using mathematical models based on Einstein’s theory of relativity. Their innovative approach uses a deep neural network to quickly predict the stability of galaxy models. This artificial intelligence-based method enables efficient verification or falsification of astrophysical hypotheses in seconds.

The research objective of Dr. Sebastian Wolfschmidt and Christopher Straub is to investigate the structure and long-term behavior of galaxies. “Since these cannot be fully analyzed by , we use mathematical models of galaxies,” explains Christopher Straub, a doctoral student at the Chair of Mathematics VI at the University of Bayreuth.

“In order to take into account that most galaxies contain a black hole at their center, our models are based on Albert Einstein’s general theory of relativity, which describes gravity as the curvature of four-dimensional spacetime.”

Lightest Black Hole or Heaviest Neutron Star? MeerKAT Uncovers a Mysterious Object in Milky Way

An international team of astronomers have found a new and unknown object in the Milky Way that is heavier than the heaviest neutron stars known and yet simultaneously lighter than the lightest black holes known.

Using the MeerKAT Radio Telescope, astronomers from a number of institutions including The University of Manchester and the Max Planck Institute for Radio Astronomy in Germany found an object in orbit around a rapidly spinning millisecond pulsar located around 40,000 light years away in a dense group of stars known as a globular cluster.

Using the clock-like ticks from the millisecond pulsar they showed that the massive object lies in the so-called black hole mass gap.

Magnetic launch of black hole jets in Perseus A

The Event Horizon Telescope collaboration, including scientists from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has recently resolved the jet base of an evolving jet of plasma at ultra-high angular resolution.

The international team of scientists used the Earth-size telescope to probe the in the nucleus of the radio galaxy 3C 84 (Perseus A), one of the closest active supermassive in our cosmic neighborhood.

These novel results provide new insight into how jets are launched, revealing that in this cosmic tug of war, the magnetic fields overpower gravity. The study is published in the journal Astronomy & Astrophysics.

Ghost in the Cosmos: Almost Invisible Galaxy Challenges Dark Matter Model

A group of astrophysicists led by Mireia Montes, a researcher at the Instituto de Astrofísica de Canarias (IAC), has discovered the largest and most diffuse galaxy recorded until now. The study has been published in the journal Astronomy & Astrophysics, and has used data taken with the Gran Telescopio Canarias (GTC) and the Green Bank Radiotelescope (GBT).

Nube is an almost invisible dwarf galaxy discovered by an international research team led by the Instituto de Astrofísica de Canarias (IAC) in collaboration with the University of La Laguna (ULL) and other institutions.

The name was suggested by the 5-year-old daughter of one of the researchers in the group, and is due to the diffuse appearance of the object. Its surface brightness is so faint that it had passed unnoticed in the various previous surveys of this part of the sky, as if it were some kind of ghost. This is because its stars are so spread out in such a large volume that “Nube” (the Spanish for “Cloud”) was almost undetectable.

Team of astronomers discovers galaxy that shouldn’t exist

A team of astronomers, led by Arizona State University Assistant Research Scientist Tim Carleton, has discovered a dwarf galaxy that appeared in James Webb Space Telescope imaging that wasn’t the primary observation target.

Galaxies are bound together by gravity and made up of stars and planets, with vast clouds of dust and gas as well as dark matter. Dwarf galaxies are the most abundant galaxies in the universe, and are by definition small with low luminosity. They have fewer than 100 million stars, while the Milky Way, for example, has nearly 200 billion stars.

Recent observations of the abundance of “ultra-diffuse galaxies” beyond the reach of previous large spectroscopic surveys suggest that our understanding of the dwarf galaxy population may be incomplete.

Astronomers Make Historic Discovery: Oldest Black Hole Ever Observed Detected

The young host galaxy, called GN-z11, glows from such an energetic black hole at its centre. Black holes cannot be directly observed, but instead they are detected by the tell-tale glow of a swirling accretion disc, which forms near the edges of a black hole. The gas in the accretion disc becomes extremely hot and starts to glow and radiate energy in the ultraviolet range. This strong glow is how astronomers are able to detect black holes.

GN-z11 is a compact galaxy, about one hundred times smaller than the Milky Way, but the black hole is likely harming its development. When black holes consume too much gas, it pushes the gas away like an ultra-fast wind. This ‘wind’ could stop the process of star formation, slowly killing the galaxy, but it will also kill the black hole itself, as it would also cut off the black hole’s source of ‘food’

Maiolino says that the gigantic leap forward provided by JWST makes this the most exciting time in his career. “It’s a new era: the giant leap in sensitivity, especially in the infrared, is like upgrading from Galileo’s telescope to a modern telescope overnight,” he said. “Before Webb came online, I thought maybe the universe isn’t so interesting when you go beyond what we could see with the Hubble Space Telescope. But that hasn’t been the case at all: the universe has been quite generous in what it’s showing us, and this is just the beginning.”