All articles tagged with #gamma ray bursts
New gamma-ray burst echoes mapped two of the Milky Way’s largest spiral arms, suggesting they’re about 10% farther from Earth than previously thought. The finding implies the galaxy may be wider and more massive, with asymmetry in its shape, prompting scientists to revisit estimates of the Milky Way’s size and mass.
New measurements from NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton suggest the Milky Way’s spiral arms extend about 10% farther and are roughly 3,500 light-years wider than previously estimated, based on X-ray echoes from gamma-ray bursts reflecting off dust in three arms (Perseus, Outer, and Outer Scutum–Centaurus). This direct geometric approach could revise our understanding of the galaxy’s mass distribution, rotation, and overall structure, though gamma-ray bursts are rare and the data come from only a handful of usable events.
Astronomers used light echoes from gamma-ray bursts observed by NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton to geometrically measure distances to dust clouds in the Milky Way’s spiral arms, finding the Outer and Outer Scutum-Centaurus arms are about 10% farther away than previously thought; the method could revise estimates of the Milky Way’s mass and arm structure, with the most distant arm’s dust cloud about 3,500 light-years thick and only a handful of usable GRBs observed over 25 years.
Astronomers used X-ray echoes from rare gamma-ray bursts observed by NASA’s Chandra and ESA’s XMM-Newton to geometrically measure dust rings in the Milky Way’s spiral arms, finding the outer arms extend farther than previously known (one distant dust cloud about 3,500 light-years across). This geometry-based method, not dependent on the galaxy’s rotation, could prompt revisions to estimates of the Milky Way’s mass and structure, though its data are limited by the rarity of bright gamma-ray bursts.
NASA and private contractor Katalyst Space Technologies launched an emergency mission to save the Neil Gehrels Swift Observatory from burning up in Earth’s atmosphere, sending the Link servicing spacecraft to intercept Swift and raise its orbit by about 150 miles (from roughly 224 miles) in a nine‑month, $30 million effort to preserve the $500 million gamma‑ray‑burst observatory.
Astronomers using X-ray data from NASA’s Chandra and ESA’s XMM-Newton measure dust-ring geometry created by distant gamma-ray bursts to map the Milky Way’s outer spiral arms, finding the arm in the far reaches is about 3,500 light-years wide and implying a potential update to the Galaxy’s size and mass; the method offers a geometry-based alternative to rotation-based estimates but relies on rare bright bursts, so more observations are needed.
Los Alamos researchers analyzed two long-duration gamma-ray bursts detected by Fermi and concluded they originated from neutron stars collapsing into black holes (collapsars) rather than mergers, prompting a reevaluation of long GRB origins. Using NASA data and the Chicoma supercomputer, the study supports a collapsar-based explanation and suggests kilonova-driven heavy-element synthesis may be more varied than previously thought; upcoming gravitational-wave observations could further clarify the links between GRBs, kilonovae, and heavy-element production.
NASA is pursuing a $30 million robotic mission to save the aging Swift gamma-ray burst observatory from orbital decay and prevent it from re-entering Earth. The plan envisions a small spacecraft rendezvousing with Swift to boost its orbit or attach a propulsion module, extending the telescope’s science life as it continues to detect and study gamma-ray bursts. Swift has been a mainstay of GRB science since 2004, and the rescue would aim to keep its rapid follow-up capabilities operational rather than risk losing the mission to re-entry.
NASA’s Vela satellites, built to monitor nuclear tests, began registering puzzling gamma-ray flashes in the late 1960s. Initially ambiguous, sixteen bursts were later identified as cosmic gamma-ray bursts, not terrestrial or solar events. Distance estimates remained contested until BeppoSAX pinpointed afterglows in 1997, proving GRBs originate billions of light-years away and transforming gamma-ray astronomy.
A comprehensive review of 65 observations from pulsars, active galaxies, and gamma-ray bursts tightens the limits on any energy-dependent variation in photon speed, finding no violation of Lorentz invariance and reinforcing Einstein’s relativity; it also refines how such limits are calculated and points to future instruments for even tighter tests.
The Vela satellites, built to detect secret nuclear tests, recorded a mysterious 1967 gamma-ray flash that didn’t fit terrestrial or solar sources, initiating gamma-ray burst research. Over time, improved timing allowed precise localization, establishing bursts as cosmic in origin. BeppoSAX’s 1997 afterglow localizations linked bursts to distant galaxies and revealed two main classes—short bursts from compact mergers and long bursts from collapsing massive stars—while extraordinary events like GRB 221009A in 2022 showed bursts can outshine almost all prior records, marking gamma-ray bursts as a central field in high-energy astrophysics.
New simulations suggest ultrahigh-energy cosmic rays hitting Earth could be atomic nuclei heavier than iron, which lose energy more slowly over cosmic distances; events like neutron-star mergers or massive star collapses into black holes may accelerate these ultraheavy nuclei, reshaping how scientists search for their sources and understand cosmic-ray acceleration.
Astronomers connecting the November 2024 gravitational-wave event S241125n with a brief gamma-ray and X-ray flash propose the merger happened inside the accretion disk of a supermassive black hole at the center of a galaxy. If true, the environment would feed rapid accretion and jets, producing light from an event usually expected to be dark, offering a new scenario for how black hole mergers in galactic nuclei might be observed. Further observations and modeling are needed to confirm this explanation.
Astronomers using NASA's Chandra X-ray Observatory and Hubble traced a short gamma-ray burst (GRB 230906A) to a neutron-star merger inside a tiny dwarf galaxy, revealed by its placement in a long tidal tail; the finding shows such powerful explosions can occur in faint hosts and helps explain how heavy elements are dispersed into galactic outskirts.
Astronomers detected a neutron-star collision in a tiny, faint galaxy inside a 600,000-light-year gas stream, about 4.7 billion light-years away, challenging where such events occur and linking them to gamma-ray bursts and the production of heavy elements like gold and platinum, with observations from Fermi, Chandra, Swift, and Hubble.