Clay weekly context brief for the Astro category (ISO week 2026-W40).

Clay tracks publications from the Astro feed list. Below are recent items from this category, each with its source and a short description of what the publication covers when one is available in the source feed.

Recent publications:
1. QCD Crossover Transfer Functions for Scalar-Induced Gravitational Waves in the PTA Band
   Source: astro-ph.CO (Cosmology and Nongalactic Astrophysics)
   Link: https://arxiv.org/abs/2609.29078
   Pulsar timing array (PTA) collaborations have reported evidence for a stochastic gravitational wave (GW) background in the nHz band.
2. Triggering star formation by free-floating planets
   Source: astro-ph.EP (Earth and Planetary Astrophysics)
   Link: https://arxiv.org/abs/2609.28744
   Recently, a population of free-floating planets has been discovered in the Galaxy.
3. Mapping the Milky Way in Six Dimensions: A contiguous, homogenised, phase-space catalogue of \textit{Gaia} DR3 tracers up to 250 kpc
   Source: astro-ph.GA (Astrophysics of Galaxies)
   Link: https://arxiv.org/abs/2609.28652
   We present a comprehensive, homogenised catalogue of $32{,}552{,}876$ stellar sources with full 6D phase-space information, spanning Galactocentric distances from the inner galaxy ($\gtrsim 5$\,kpc) to the outer halo ($\sim\!250$\,kpc).
4. 3D Radiation Hydrodynamics of Blue Supergiant Envelopes
   Source: astro-ph.SR (Solar and Stellar Astrophysics)
   Link: https://arxiv.org/abs/2609.28656
   We present the first 3D radiation hydrodynamical simulation of the outer envelope of a blue supergiant.
5. Uncertainty-Aware Tidal Disruption Event Classification : A Host-Agnostic Probabilistic Random Forest Approach
   Source: astro-ph.IM (Instrumentation and Methods for Astrophysics)
   Link: https://arxiv.org/abs/2607.28510
   The classification of Tidal Disruption Events in large-scale photometric surveys is challenging because deterministic machine learning models produce overconfident misclassifications under varying data quality and low signal-to-noise conditions.
6. Variable opacity and accretion-column regimes of magnetized neutron stars
   Source: astro-ph.HE (High Energy Astrophysical Phenomena)
   Link: https://arxiv.org/abs/2609.28134
   Radiation-supported accretion columns of magnetized neutron stars can operate in several distinct regimes.
7. Testing cosmic acceleration from thermogravity without vacuum energy
   Source: astro-ph.CO (Cosmology and Nongalactic Astrophysics)
   Link: https://arxiv.org/abs/2609.29206
   We present a first background-level observational test of a thermogravity theory in which the Einstein equations are clipped to a trace-free version, the cosmological constant $\Lambda$ does not gravitate, and controlled violations of energy conservation obstruct the usual reinstatement of $\Lambda$ as an integration constant.
8. On the Long-Term Orbital Behaviour of Hilda Asteroids - I. Global Stability Patterns and Catalogue
   Source: astro-ph.EP (Earth and Planetary Astrophysics)
   Link: https://arxiv.org/abs/2609.28847
   The Hildas are objects trapped in 3:2 mean-motion resonance (MMR) with Jupiter, and are a fascinating window into the Solar system's formation and evolution.
9. Cluster Membership Probabilities: A Review of Methods and Gaia Applications
   Source: astro-ph.GA (Astrophysics of Galaxies)
   Link: https://arxiv.org/abs/2609.28753
   Reliable stellar-cluster membership is essential for deriving cluster ages, distances, reddenings, metallicities, mass functions, dynamical parameters, and Galactic-structure tracers.
10. A comprehensive multi-wavelength study of two X-ray emitting Be stars
   Source: astro-ph.SR (Solar and Stellar Astrophysics)
   Link: https://arxiv.org/abs/2609.28719
   We present a multi-wavelength study of two X-ray-emitting Be stars, CXOU J052218.4+332820 (Star 1) and CXOU J052304.2+332846 (Star 2), identified from the LAMOST DR5 Hot emission-line stars catalog.
11. A Split-Flux Method for Dust-Gas Two-Fluid Simulations from Strong to Weak Coupling
   Source: astro-ph.IM (Instrumentation and Methods for Astrophysics)
   Link: https://arxiv.org/abs/2607.24418
   We develop a new method for simulating pressureless fluids of neutral dust coupled to magnetohydrodynamic gas through dust-gas drag.
12. Shock-free super-Eddington accretion onto magnetized neutron star
   Source: astro-ph.HE (High Energy Astrophysical Phenomena)
   Link: https://arxiv.org/abs/2609.28092
   Strong magnetic fields allow accreting neutron stars to form magnetically controlled funnel flows.
13. Limits on Primordial Black Hole Evaporation from LUX-ZEPLIN
   Source: astro-ph.CO (Cosmology and Nongalactic Astrophysics)
   Link: https://arxiv.org/abs/2609.29462
   The LUX-ZEPLIN (LZ) collaboration recently reported a singular anomalous nuclear recoil event at $248 \pm 23 \; \rm keV$, accompanied by a strict null result for unexplained excesses in their primary $5.4-50 \; \rm keV$ search window.
14. A Collisional Origin for Ice-rich Iapetus and Titan's Anomalous Eccentricity
   Source: astro-ph.EP (Earth and Planetary Astrophysics)
   Link: https://arxiv.org/abs/2609.28948
   We test whether collisions involving Titan can eject enough water-rich material onto sufficiently distant Saturn-bound orbits to form Iapetus, while also accounting for Titan's orbital eccentricity.
15. High-z galaxies with the JWST and the ELT: Toward Ever-finer Detail
   Source: astro-ph.GA (Astrophysics of Galaxies)
   Link: https://arxiv.org/abs/2609.29072
   The exploration of the early Universe is being transformed by the James Webb Space Telescope (JWST), which delivers unprecedented angular resolution at infrared wavelengths and opens a unique window redward of the K band (2um).
16. Central stars of newly discovered infrared nebulae: eruptive Be stars PY Gem and HD253659
   Source: astro-ph.SR (Solar and Stellar Astrophysics)
   Link: https://arxiv.org/abs/2609.28889
   The presence of a nebula around massive hot stars often works as an indicator that the object is either in an advanced evolutionary stage or a rare product of close binary interaction.
17. Red noise and evolving signals: a complete frequentist approach to supermassive black hole binary searches with pulsar timing arrays
   Source: astro-ph.IM (Instrumentation and Methods for Astrophysics)
   Link: https://arxiv.org/abs/2606.07330
   Searches for gravitational waves (GWs) from isolated supermassive black hole binaries (SMBHBs) in pulsar timing array (PTA) data require simultaneous estimation of signal and noise parameters, so the dimensionality of the fit scales with the number of observed pulsars.
18. First X-ray detection of symbiotic nova CN Cha with eROSITA/SRG
   Source: astro-ph.HE (High Energy Astrophysical Phenomena)
   Link: https://arxiv.org/abs/2609.28079
   Aims.
19. Two-rung ladder: $H_0$ from Tip of the Red Giant Branch and geometric anchors alone
   Source: astro-ph.CO (Cosmology and Nongalactic Astrophysics)
   Link: https://arxiv.org/abs/2609.29996
   We infer the Hubble constant $H_0$ from the ~400 Extragalactic Distance Database hosts with a tip of the red giant branch (TRGB) distance, calibrated on the geometric anchors of the Large Magellanic Cloud and NGC 4258.
20. A Possible Complication of Using the 4.14 {\mu}m band to Assess D/H Ratios on Icy Bodies
   Source: astro-ph.EP (Earth and Planetary Astrophysics)
   Link: https://arxiv.org/abs/2609.29003
   Determining isotopic ratios on the surfaces of extraterrestrial objects can provide insight into their formation conditions and evolution.
21. Mass-Dependent Dark Matter Deficit from Inelastic Scattering
   Source: astro-ph.GA (Astrophysics of Galaxies)
   Link: https://arxiv.org/abs/2609.29114
   Recent stellar-kinematic and neutral-hydrogen observations indicate a dark matter deficit within the central tens of kiloparsecs of nearby galaxies that grows systematically with stellar mass relative to hydrodynamical simulations.
22. Study of Chromospheric Global-Scale Flows using Local Correlation Tracking Across the past 10 Solar Cycles
   Source: astro-ph.SR (Solar and Stellar Astrophysics)
   Link: https://arxiv.org/abs/2609.28890
   Global-scale solar surface flows, including differential rotation and meridional circulation, provide key observational constraints on the solar dynamo.
23. Computational advances and challenges in simulations of turbulence and star formation
   Source: astro-ph.IM (Instrumentation and Methods for Astrophysics)
   Link: https://arxiv.org/abs/2510.12203
   We review recent advances in the numerical modeling of turbulent flows and star formation.
24. A Diagnostic Method for Proto-Neutron Star Magnetic Fields by Supernova Fallback Neutrinos
   Source: astro-ph.HE (High Energy Astrophysical Phenomena)
   Link: https://arxiv.org/abs/2609.28057
   Young isolated neutron stars exhibit a wide range of magnetic field strengths.
25. The Optical Expansion Scalar in Cosmological Perturbation Theory
   Source: astro-ph.CO (Cosmology and Nongalactic Astrophysics)
   Link: https://arxiv.org/abs/2609.30108
   Within the geometric optics approximation, the optical expansion scalar describes the local rate of change in the amplitude of a wave or the area of a light bundle propagating through the Universe.
26. Exoplanet Detection Techniques: Radial Velocity
   Source: astro-ph.EP (Earth and Planetary Astrophysics)
   Link: https://arxiv.org/abs/2609.29378
   The radial velocity (RV) technique enabled the discovery of the first exoplanets orbiting Sun-like stars.
27. Stellar Collisions from Self-consistent Stellar Dynamics Around Growing Supermassive black Holes
   Source: astro-ph.GA (Astrophysics of Galaxies)
   Link: https://arxiv.org/abs/2609.29136
   The centers of galaxies harbor the densest stellar environments, where a massive black hole (MBH) accelerates stars to such high velocities that direct collisions can result in high-energetic phenomena, such as gravitational wave sources, kilonovae, and supernova-like transients.
28. Estimates of magnetic field strength in the solar corona using observations of thermal radio emission at low frequencies
   Source: astro-ph.SR (Solar and Stellar Astrophysics)
   Link: https://arxiv.org/abs/2609.29602
   Measurements of the magnetic field strength in the solar corona at heliocentric distances $r\,{\gtrsim}\,1.1\,R_{\odot}$, using observations other than transient radio bursts, are rare.
29. The Chandra-Gaia Catalog of Counterparts: Resolving ambiguous Gaia matches to X-ray sources in the Chandra Source Catalog using Machine Learning
   Source: astro-ph.IM (Instrumentation and Methods for Astrophysics)
   Link: https://arxiv.org/abs/2606.19329
   We present a framework to cross-match sources from the Chandra Source Catalog (CSC v2.1) with optical sources from Gaia Data Release 3.
30. Semi-Analytic Solutions For Warped, Super-Eddington Accretion Disks with Outflows
   Source: astro-ph.HE (High Energy Astrophysical Phenomena)
   Link: https://arxiv.org/abs/2609.28017
   The discovery of billion solar mass black holes at high redshift challenges any standard Eddington-limited growth model.
31. Statistics of large-scale structure from the transition probability of Lagrangian trajectories
   Source: astro-ph.CO (Cosmology and Nongalactic Astrophysics)
   Link: https://arxiv.org/abs/2609.30251
   We describe a probabilistic approach to gravitational clustering.

Sources in this brief: astro-ph.CO (Cosmology and Nongalactic Astrophysics); astro-ph.EP (Earth and Planetary Astrophysics); astro-ph.GA (Astrophysics of Galaxies); astro-ph.HE (High Energy Astrophysical Phenomena); astro-ph.IM (Instrumentation and Methods for Astrophysics); astro-ph.SR (Solar and Stellar Astrophysics).
Selected 31 of 365 available items for this weekly brief.