This week in cosmology brought new tools for solving long-standing cosmic puzzles and fresh measurements of the universe's expansion. Researchers developed a neural network method to quantify tensions between different maps of the cosmos, finding disagreement between the cosmic microwave background and observations of distant objects that suggests our understanding of cosmic motion may be incomplete. In a separate effort, astronomers refined measurements of the Hubble constant—how fast the universe is expanding—to 1.1% precision using corrected supernova data, though this still leaves unresolved tension with other measurement techniques. A large survey using the DESI telescope examined the Lyman-alpha forest, a pattern in distant galaxy light, to constrain dark energy and the universe's geometry, with results that partially conflict with predictions from earlier cosmic microwave background studies. On smaller scales, researchers used X-ray observations to map a filament of hot gas connecting galaxy clusters, showing how these massive structures link together across space. Two separate studies tackled the question of dark matter's shape in galaxies, with one technique showing that dark matter cores are typically rounded rather than sharp-pointed, while another explored how exotic dark matter particles called Q-balls could naturally flatten galaxy centers. Finally, a new method that combines gravitational wave signals from colliding black holes with hydrogen gas maps promises to measure cosmic expansion and structure with unprecedented sub-1% precision.
This week in planetary science brought detailed observations of disk structures around young stars and discoveries about moons in the outer solar system. The James Webb Space Telescope captured crystalline silicates forming in real time within an accretion burst around the young star EC 53, where rapid heating and stirring of dust particles created visible crystal structures that can travel outward to influence planet formation. Meanwhile, observations of Neptune's inner moons and rings revealed signatures of water and magnesium-rich minerals, suggesting these bodies preserve ancient material from the early solar system, possibly disrupted when Triton arrived in the Neptune system. New high-resolution imaging of the protoplanetary disk around TW Hya showed detailed dust structures and warping patterns likely caused by embedded planets, though direct detection of those planets remains elusive. In a different direction, measurements of a small Jovian moon named Kallichore using Hubble and ground-based telescopes determined it is roughly three kilometers long with an elongated, egg-like shape, providing crucial information for planning a close encounter by the upcoming JUICE spacecraft in 2031. Finally, spectroscopic observations of the young star RY Lup revealed radial velocity variations repeating every 3.75 days, consistent with one or more unseen companions orbiting the star and potentially carving the warped disk structures observed around it.
Observations of a distant quasar with the XRISM space telescope reveal vigorous turbulence in the surrounding galaxy cluster driven by powerful winds from the quasar itself, with gas moving at speeds around 300 kilometers per second and the quasar dumping between one and ten percent of its energy into the cluster. A new measurement of the supermassive black hole at the center of the galaxy NGC 5102 using telescope data and orbital modeling puts its mass at approximately 1.3 million times Earth's mass, confirming the reliability of this measurement technique. Astronomers cataloged over 6,400 young star clusters in the Fireworks Galaxy using an automated computer vision tool applied to Hubble Space Telescope images, allowing them to study how these massive clusters form and evolve. Research into extremely compact starburst galaxies found they are consuming their gas at extraordinarily rapid rates—equivalent to running out of fuel in under a billion years—indicating they are rapidly transitioning from intensely star-forming systems to quiescent ones. The James Webb Space Telescope detected molecular hydrogen winds flowing outward from the young star HV Tau C at speeds of 30 to 60 kilometers per second, revealing how young stars shed material as they grow by accreting matter from their surrounding disks. An analysis of the galaxy cluster A3266 discovered it is connected to neighboring galaxy groups through hot-gas filaments stretching across millions of light-years, forming part of a cosmic web where clusters exchange material and interact gravitationally. Finally, observations of distant quasars at the universe's early epochs show that their compact inner jets are embedded within much larger radio-emitting structures, suggesting the jets grow and expand significantly over cosmic time.
This week in high-energy astrophysics saw discoveries spanning stellar explosions, binary star dynamics, and surveys of energetic objects across the sky. Observations with the XRISM space telescope detected vigorous turbulence in the galaxy cluster around quasar H1821+643, driven by winds so powerful that iron atoms were spread across space at speeds of 300 kilometers per second, revealing that the quasar is channeling between one and ten percent of its total energy into the surrounding cluster. A new model proposes that collisions between neutron stars and white dwarfs can produce the rare, long-duration gamma-ray bursts observed by astronomers, with the neutron star's powerful magnetic field triggering a chain of explosions that synthesize heavy elements like gold and lead. Astronomers monitoring the binary star system 9 Sagittarii detected radio emissions at periastron passage—the point where the two stars come closest—that were stronger than theories of colliding stellar winds would predict, suggesting the magnetic field structure in the collision zone is more complex than standard models assume. The SRG/eROSITA all-sky survey released its second data release, cataloging nearly two million X-ray sources detected across the western half of the sky and matched to counterparts at other wavelengths, roughly doubling the haul of previously known energetic objects. In a triple star system containing pulsar PSR J0435+3233, astronomers discovered a third companion star orbiting with a 70-year period, explaining why this pulsar spins down faster than others of its kind. JWST observations of supernova SN 2010jl revealed an exceptionally large mass of dust formed in the explosion's aftermath, among the largest amounts ever detected from a stellar explosion and potentially significant for understanding dust production in galaxies.
This week in instrumentation and methods brought advances across several observational frontiers. The eROSITA all-sky survey identified how bright optical light from stars can contaminate and mask X-ray signals in telescope data, finding that stellar brightness systematically affects what X-ray emissions astronomers can actually detect. The James Webb Space Telescope used principal component analysis to break down atmospheric variability on the brown dwarf SIMP J013656.5+093347 into two main patterns, revealing that its complex weather is driven by atmospheric regions rotating into and out of view. A new algorithm called Syntriod dramatically improves the ability to find orbital parameters in binary star systems even when observational data is sparse or incomplete, achieving success rates above 83 percent in challenging cases and over 99 percent with good data. PhySR, a physics-informed neural network, can sharpen radio telescope images up to four times beyond their original resolution while preserving fine details and maintaining accuracy across different image sizes. The Sloan Digital Sky Survey released its twentieth data compilation, including the first complete all-sky spectra from the BOSS survey and coordinated observations with eROSITA, along with preparations for the Local Volume Mapper to study nearby galaxies and stars. Two gravitational wave analysis tools showed major progress: GSpyNetTree-O4 correctly identified 97 percent of instrumental glitches in LIGO data to distinguish them from real signals, while a new real-time parameter estimation technique reduced analysis time to around one minute by combining advanced computational methods. Finally, assessments of the planned Einstein Telescope confirmed that achievable instrumental specifications can meet the sensitivity requirements needed to detect gravitational waves from distant supernovae, neutron star mergers, and other cosmic events across the full frequency range the detector will observe.
This week in stellar astrophysics brought discoveries across multiple stages of star and stellar system evolution. Observations with the James Webb Space Telescope revealed crystalline silicates forming in the disk around the young star EC 53 during an accretion burst, when material rapidly heats to temperatures that transform the silicate particles into crystals that can later seed planet formation. In an entirely different regime, analysis of eight white dwarfs using data from Kepler, TESS, and Gaia found that most have thicker outer layers than expected, and these stars appear systematically cooler than their spectral properties suggest—a discrepancy that remains unresolved. A study using XMM-Newton observed 51 X-ray-bright young stellar objects in both quiet and outburst states, finding multi-temperature structures in their hot coronae consistent with magnetic reconnection as the source of their X-rays. Meanwhile, detailed radial velocity measurements of the young star RY Lup detected periodic variations over 327 days that could indicate the presence of two unseen companion objects, though the data remain ambiguous between a binary companion scenario and alternative explanations. Parker Solar Probe detected energy transfer between colliding solar wind streams, finding that nearly half the energy dissipated converted to heat while the other half accelerated the solar wind further. Finally, the eROSITA all-sky survey identified optical loading—the masking of faint X-ray signals by bright optical starlight—as a significant source of contamination in X-ray catalogs of stars, affecting the reliability of stellar X-ray emission surveys.