Cosmic rays are extremely energetic charged particles that zoom through space and bombard the Earth’s atmosphere. Since cosmic rays get diverted by magnetic fields on their way to Earth, tracing their origins is more difficult. However, tiny, nearly massless particles called neutrinos, and photons at similar energies, can be used to trace cosmic rays back […]
Since high-energy astrophysical neutrinos were first observed in 2013, the IceCube Neutrino Observatory at the South Pole has continued searching for their elusive sources. So far, evidence of high-energy neutrino emission has been found from the blazar TXS 0506+056, the active galaxy NGC 1068, and most recently, the Milky Way. Still, neutrino emission from these […]
The nature of dark matter—roughly 85% of all matter in the universe—is one of the most important unresolved questions in modern physics. Thus far, no experiment has been able to determine what dark matter is made of. A possible candidate for dark matter are the hypothesized weakly interacting massive particles (WIMPs), which hardly interact with […]
Extremely energetic charged particles called cosmic rays are accelerated by violent cosmic objects before raining down on Earth from all directions. Protons and heavier nuclei make up these cosmic rays, which can then collide with other particles in the atmosphere to produce secondary particles that cascade into so-called “air showers.” For more than a century, […]
Active galactic nuclei (AGNs) are leading candidates for the sources of high-energy astrophysical neutrinos—tiny, nearly massless particles—detected by the IceCube Neutrino Observatory at the South Pole. This is demonstrated by the real-time multimessenger detection of the blazar TXS 0506+056 and recent evidence of neutrino emission from NGC 1068 from a separate time-averaged study. However, the […]
When cosmic rays crash into the Earth’s atmosphere, air showers containing atmospheric muons and neutrinos are produced that rain down on Earth. During their journey, atmospheric neutrinos can morph or “oscillate” between three different flavors: electron, muon, and tau. These neutrinos can interact weakly with other particles and, thus, are still observable by detectors such […]
Neutrinos are tiny, nearly massless particles that traverse long distances across the universe, interacting with matter only through the weak force. They come in three different types, or “flavors”—electron, muon, and tau—and during their journey through the atmosphere and the Earth can transform, or “oscillate,” from one flavor to another. Over the last few decades, […]
Ever since high-energy astrophysical neutrinos were first observed in 2013, the IceCube Neutrino Observatory at the South Pole has been hunting for their astronomical sources. Active galactic nuclei (AGNs) are promising candidates as sources of astrophysical neutrinos given their very high levels of electromagnetic emission—from radio waves to gamma rays—that can outshine their host galaxies […]
Almost two years ago, the IceCube Neutrino Observatory at the South Pole announced evidence for high-energy neutrinos spewing from the “nearby” active galaxy NGC 1068. NGC 1068 is an active galactic nucleus (AGN) with a central, supermassive black hole that actively gobbles up surrounding matter. Classified as a Seyfert galaxy, NGC 1068 is not dominated […]
Neutrinos are tiny “ghostlike” particles that traverse long distances across the universe, interacting with matter only through the weak force. They come in three different types or “flavors”—electron, muon, and tau—and during their journey through the atmosphere and the Earth can transform from one flavor to another. This phenomenon, called neutrino oscillation, is a subject […]