Tag

Gamma Rays

All articles tagged with #gamma rays

Sharp Gamma-Ray Hint Sparks Fresh Dark Matter Debate
space-and-spaceflight21 hours ago

Sharp Gamma-Ray Hint Sparks Fresh Dark Matter Debate

A Chinese Academy of Sciences team reports a sharp gamma-ray line in 15.5 years of Fermi Gamma-ray Space Telescope data, arguing it provides strong direct evidence for dark matter in the form of weakly interacting massive particles (WIMPs). The authors say the signal fits expectations for WIMP annihilation, but gamma-ray lines can arise from instrumental or astrophysical sources, so confirmation will require further data and independent verification as new gamma-ray observatories come online.

Milky Way Hosts a Proton PeVatron Far More Energetic Than the LHC
science19 days ago

Milky Way Hosts a Proton PeVatron Far More Energetic Than the LHC

Astronomers have identified LHAASO J1912+1014u as a proton PeVatron in the Milky Way, accelerating protons to PeV energies—well beyond the Large Hadron Collider—based on multiwavelength data from Fermi-LAT, FUGIN, and Chandra that rule out electrons as the gamma-ray source; the exact engine remains unknown, but such galactic PeVatrons may be common and help explain the origin of the most energetic cosmic rays.

Dark Matter Could Decay into Gravitons and Glow as Gamma Rays
science22 days ago

Dark Matter Could Decay into Gravitons and Glow as Gamma Rays

A new proposal suggests dark matter may decay into gravitons, which could convert to photons via the Gertsenshtein effect as they travel through large-scale magnetic fields in intergalactic filaments, producing an excess gamma-ray signal. If true, this would shift searches from galactic centers to intergalactic space and could be tested with Fermi data today, with future missions like the Advanced Particle-astrophysics Telescope boosting sensitivity by an order of magnitude.

Twin Supernova Remnants Hint at Exploding Stellar Siblings
space2 months ago

Twin Supernova Remnants Hint at Exploding Stellar Siblings

Using 16 years of Fermi gamma-ray data, astronomers found gamma rays from the faint remnant G189.6+3.3 overlapping the Jellyfish Nebula, supporting a binary-star origin where both exploded and left two interacting remnants about 6,000 light-years away in Gemini; ages range ~8–9k and 20k–110k years, with simulations showing such dual explosions are plausible and possibly linked to PeVatron acceleration.

Magnetar-powered gamma glow lights up a distant supernova
space3 months ago

Magnetar-powered gamma glow lights up a distant supernova

NASA’s Fermi detected gamma rays from the luminous core-collapse supernova SN 2017egm (NGC 3191, about 440 million light-years away), supporting the idea that a newborn magnetar—an ultra‑magnetized neutron star—powers the explosion. A magnetar wind nebula and related particle interactions could boost gamma-ray production and reprocess energy into visible light, explaining the unusually bright display; gamma rays begin to leak out as debris expands, with the early light curve matching models though late-time fading remains puzzling. The study also notes the upcoming Cherenkov Telescope Array could detect similar events up to ~500 million light-years, advancing understanding of magnetar engines. The work appeared in Astronomy & Astrophysics on May 20, 2026.

Novae Unveiled: Real-Time Interferometry Reveals Multi-Stage Ejections and Gamma Rays
space7 months ago

Novae Unveiled: Real-Time Interferometry Reveals Multi-Stage Ejections and Gamma Rays

Astronomers using the CHARA Array and other telescopes captured real-time images of two novae (V1674 Herculis and V1405 Cassiopeiae), revealing complex, multi-stage gas outflows and gamma-ray emissions—showing that nova explosions are not single blasts and linking surface nuclear processes to the geometry of ejected material and high-energy radiation.

Novae Unleash Dual Jets: High-Res Images Rewrite Stellar Explosions
space7 months ago

Novae Unleash Dual Jets: High-Res Images Rewrite Stellar Explosions

High-resolution CHARA Array images of 2021 novae V1674 Herculis and V1405 Cassiopeiae reveal complex, jet-driven eruptions in binary white-dwarf systems, including perpendicular outflows and a delayed ejection likely tied to a common-envelope phase. The gamma-ray signals observed by NASA’s Fermi coincide with internal shocks in the debris, linking surface nuclear reactions to high-energy radiation and challenging the idea of novae as simple spherical shells. These findings, published in Nature Astronomy, position novae as natural laboratories for extreme physics.

Gamma-Ray Tests Tighten Lorentz-Invariance Bounds, Not Break Special Relativity
science7 months ago

Gamma-Ray Tests Tighten Lorentz-Invariance Bounds, Not Break Special Relativity

New analysis of gamma-ray flares from pulsars, active galactic nuclei, and gamma-ray bursts finds no energy-dependent speed of light, placing stricter bounds on Lorentz-violating effects predicted by some quantum gravity theories. The results tighten the allowed violations by about 1.5 orders of magnitude and offer a framework for integrating new data into the SME; in short, SR remains consistent, while the search for quantum-gravity signatures continues.

Scientists Recreate Cosmic Fireballs at CERN to Uncover Gamma-Ray Mysteries
science9 months ago

Scientists Recreate Cosmic Fireballs at CERN to Uncover Gamma-Ray Mysteries

Scientists at CERN recreated cosmic jet conditions using particle accelerators to investigate missing gamma-rays from blazars, finding that plasma beam instabilities are too weak to explain the phenomenon, which supports the idea of relic magnetic fields in intergalactic space. This experiment provides new insights into cosmic jet physics and the universe's magnetic history.