Papers for Monday, Jun 01 2026

We measure the proper motion dipole of quasars observed by Gaia to determine the acceleration of the Solar System with respect to the quasar rest frame. We characterise the full angular power spectrum of the proper motion field using the pseudo-$C_\ell$ formalism and employ simulation-based inference to jointly constrain the dipole and higher multipole power. Cross-correlation with the Gaia scanning strategy, stellar density, and stellar proper motion maps is used to diagnose the origin of systematic power beyond the dipole. We apply this framework to both the Gaia EDR3 quasar catalogue and the Quaia catalogue. The inferred acceleration is consistent with the previous determination, but the credible intervals widen by factors of 1.5 to 2.5 when higher-multipole degeneracies are properly marginalised, indicating that previous uncertainty estimates were optimistic. Our best estimate, based on the Quaia catalogue is $(g_x,\, g_y, \,g_z) =( 0.40^{+0.70}_{-0.70},\,-5.09^{+0.54}_{-0.54},\,-2.40^{+0.55}_{-0.58}) \;\mu as \,yr^{-1}$, corresponding to an amplitude of $5.72_{-0.52}^{+0.53}\,\rm \mu as\,yr^{-1}$. The acceleration shows no significant dependence on source redshift, providing further evidence for its kinematic origin.

We show that the GW170817-GW190814 tension can be reconciled within General Relativity by a structured causal EoS basin found with a Constrained Evolutionary TOV Discovery pipeline (CETD). The basin contains ~1.4x10^4 unique EoS with M_max = 2.3-2.8 M_sun, R_1.4 = 11.97-12.29 km, Lambda_1.4 <= 580, and double-peaked sound speeds reaching c_s^2/c^2 = 0.86-0.99.

We present the EPS Research Astro-RAG Platform (v1.0), an open-science research infrastructure providing four machine-readable, cross-epoch astrophysical corpora, 120 verified executable Jupyter notebook examples, a QuickStart reproducibility pathway, an educational High-School Exploration Track, and a roadmap for LLM-assisted retrieval-augmented generation (RAG) research workflows. The platform spans the full observable cosmic epoch from the local universe (z = 0) to the epoch approaching reionization (z ~ 6), providing the first unified kinematic dataset connecting HI 21cm rotation curves, Milky Way globular cluster dynamics, and high-redshift ALMA [CII] morpho-kinematics under a common schema and analysis framework. The four corpora contain 772 total objects: 438 HI-traced galaxies (Unified HI Rotation Curve Corpus v7.0), 129 dwarf/irregular galaxies (Dwarf/Irregular HI Corpus v1.0), 174 Milky Way globular clusters (GC Corpus v1.3.1), and 31 star-forming galaxies at z = 4.26-5.68 (High-z Kinematic Corpus Z1). The Unified HI corpus preserves the full fidelity of the Case Western Reserve University SPARC database (Lelli et al. 2016), including all photometric decomposition components and surface brightness profiles, augmented with THINGS, LITTLE THINGS, and WALLABY DR2 data. The unifying scientific framework is the omega kinematic correction of Flynn & Cannaliato (2025), which reveals a robust sign reversal in the boundary-point angular velocity omega from positive values at z = 0 (SPARC mean +7.06 +/- 3.26 rad/Gyr) to negative values at z ~ 5 (Z1 median -13.05 rad/Gyr), motivating future RAMSES cosmological simulations. All corpora are released under CC BY 4.0 at Zenodo with permanent DOIs, and the platform is archived at this https URL (DOI: https://doi.org/10.5281/zenodo.20398430).

The regolith of rocky bodies, such as planets or asteroids, generally settles under gravity conditions different from those of Earth. The behavior of granular material is not easily scalable for different gravities. To predict these highly complex systems where cohesive inter particle forces can be comparable to gravitational forces, we need simulations and experiments. We did experiments on settling of three different granular samples in varying reduced gravities and examined their packing densities. We used a high precision linear stage to artificially induce reduced gravities inside the zero $g$ environment provided by the ZARM drop tower and observe the settling of our samples. The three samples were fine basalt with particle diameters of $1\text{-}200\,\mu$m, coarse basalt with $2\text{-}5\,$mm and glass beads with $750\text{-}1000\,\mu$m. The artificial gravities were $150,\,250,\,500,\,750$ and $1000\,$mm/s$^2$ and therefore ranged from large asteroid gravity to almost moon gravity. We saw the granular samples have higher volumes in lower gravities and therefore lower packing densities, we also saw the fine basalt be the most sensitive to changes in gravity, up to $+19.6\,\%$ in volume for $250\,$mm/s$^2$, followed by the coarse basalt particles, up to $+12.2\,\%$ for $150\,$mm/s$^2$ and the glass beads packing density being the least sensitive to changes in gravity, up to $+4.25\,\%$ for $250\,$mm/s$^2$. With these experiments we show change in volume is not solely dependent of particle size but also roughness and uniformity, we provide real life experimental data to validate theoretical works and highlight the role of cohesive forces in low gravity environments.

High-redshift galaxies have smaller radii, harder ionizing continua, and higher ionizing photon production efficiencies than lower redshift systems, which implies a corresponding evolution in nebular conditions. A key metric to quantify gas properties is the ionization parameter, q, the ratio of the local ionizing photon flux to the local hydrogen density. The ionization parameter is often inferred from observed emission line ratios, e.g., O32=[O III]/[O II]. Prior to JWST, statistical samples of ionization parameter-sensitive emission lines in the rest-frame optical remained inaccessible at high-z. We investigate the dimensionless ionization parameter, U=q/c at 3<z<9, inferred using Cloudy photoionization models from the O32 ratios for 434 galaxies in the RUBIES survey with JWST/NIRSpec PRISM and G395M spectroscopy, constituting the largest high-z population study of U to date. We compare to lower-redshift samples from SDSS, LEGA-C, and KBSS to probe the evolution of U from 0<z<9. We find that U increases with redshift and specific star formation rate (sSFR), and decreases with stellar mass. We combine the predictive power with multivariate relations to estimate U from redshift, stellar mass, and sSFR for use in cases where O32 is not available from spectroscopy, and show that U increases with redshift even at fixed stellar mass and sSFR by a factor of ~4 from z=2 to z=6. Crucially, and in contrast to previous linear best-fit calibrations, our inference results in a systematic uncertainty in log U of ~0.3 dex at zero measurement uncertainty due to the wide range of photoionization models that predict the same O32 ratio without informative priors. Finally, we discuss future modeling frameworks to accept many observed emission lines to simultaneously constrain gas-phase abundances, densities, ionizing sources, and ionization parameters to high accuracies for individual galaxies.

We present a set of metrics and methods for testing and comparing a range of modern gradient-free Markov Chain Monte Carlo (MCMC) samplers against the commonly used Metropolis-Hastings (MH) algorithm. The goal is to quantify key performance metrics, including sampler ergodicity, robustness and overall likelihood performance. To provide a controlled and interpretable testbed, we use the Rosenbrock function and Neal's funnel as representative unimodal cases, while Gaussian random likelihood landscapes in three, five, and eight dimensions serve as multimodal test scenarios. The samplers considered include affine-invariant moves from the literature, such as the stretch and walk moves, the differential evolution move, and the snooker move. We additionally introduce two novel variations: a modified stretch move that incorporates a Principal Component Analysis (PCA) transformation, and a hybrid blend move that combines features of both differential evolution and stretch dynamics. Beyond sampler evaluation, we demonstrate reconstructing likelihood landscapes from sampled points using a quadtree algorithm. Additionally, we explore the use of optimisation algorithms to refine the best parameter set in terms of its likelihood, and find consistent improvements in log-likelihood values, with the post-sampling gain becoming more significant in higher-dimensional problems. Our comparative results of sampler testing show that the differential evolution algorithm, when tuned to a target acceptance fraction of 25%, consistently outperforms all other samplers in terms of ergodicity, robustness, and likelihood performance.

The detection of near-Earth asteroids (NEAs) is critical for planetary defense and for advancing our understanding of the small-body population in the Solar System. Traditional detection techniques, including optical and radar, are the cornerstone of NEA discoveries. However, these are limited by observational constraints. We investigate whether the Laser Interferometer Space Antenna (LISA), a future space-borne gravitational wave detector, might detect and constrain the parameters of NEAs through their gravitational effect on the spacecraft test masses during a close approach at the minimum orbital intersection distance. We modeled the gravitational perturbations of the test masses on the LISA spacecraft exerted by a passing NEA. Based on this, we computed its signal-to-noise ratio (S/N) to determine detectability using the LISA requirements. Furthermore, we used the Fisher information formalism to estimate the uncertainties on the state vector and mass of the asteroid given it is detected. These estimates provide a first-order assessment of the LISA capability to resolve NEA parameters under favorable encounter geometries. The Fisher information study showed that the fractional uncertainty on the asteroid mass scales as the inverse of the S/N. Consequently, a detection with an S/N $\geq 5$ yields a mass determination with an uncertainty of $\sim20\%$ at most. In contrast, the state vectors exhibit considerably larger uncertainties as they depend significantly on the geometry of the close approach. Nevertheless, for very high S/N cases, this precision may be comparable to the uncertainties obtained by some of the current observational methods. The analysis of the correlation matrices confirms that each close encounter produces a specific signal and provides a practical means to assign independent error bars to the recovered state vector.

We discuss the implications of the nebular dust attenuation curves derived for 24 galaxies at z=1.5-4.4 with multiple detections of HI Balmer and Paschen recombination emission lines from the JWST/AURORA survey. The total attenuation of Ha is ~0.20 dex larger on average than the values obtained with the commonly adopted combination of the Balmer decrement and the Galactic extinction curve. Nebular-line SFRs and SED-based SFRs are consistent on average when using the MOSDEF attenuation or SMC extinction curves for the latter. The relation between nebular and stellar reddening is consistent with a scenario where the Paschen lines are sensitive to heavily reddened OB associations, while relatively unreddened OB associations contribute significantly to the Balmer line and UV continuum emission. There is a stark contrast between the low Rv (or steepness) of stellar dust attenuation curves and the high Rv (or flatness) of nebular dust attenuation curves. We suggest that the latter could be reflective of a more porous medium established by strong feedback from massive stars. For the youngest galaxy in the sample, the stellar reddening curve is identical to the nebular attenuation curve, in accordance with our expectation that OB associations dominate the stellar continuum emission at all wavelengths for this very young galaxy. Larger samples will be needed to determine whether this conclusion holds for young galaxies in general, and provide further insights into the dust and metals mixing timescale on the scale of HII regions.

Galaxy cluster strong gravitational lensing plays a central role in precision cosmology, yet robust theoretical predictions have lagged behind an abundance of high-quality strong lensing observations. This shortfall reflects both a mismatch between the geometry of the strong-lensing problem and standard cubic simulation boxes, and the fundamental tension between simulation volume and resolution. Consequently, many current forecasts adopt hybrid approaches that extract individual lenses from simulations and combine them with analytic or observed source populations positioned near caustics. These methods often omit correlated and/or uncorrelated line-of-sight (LoS) structure, or include it in ways that do not preserve correlations across redshift. Here we present a fully simulation-based procedure that generates strong-lensing images directly from particle data, drawing the lens, source, and all intervening resolved objects self-consistently from the simulated large-scale structure. Our approach combines a structure-preserving remapping of the simulation volume into a lensing-appropriate geometry with multi-plane ray tracing, enabling the use of uniform simulation boxes that resolve both cluster-scale primary lenses and high-redshift source galaxies. We demonstrate the method by generating example light cones and images using IllustrisTNG data, then use these results to conservatively quantify the impact of LoS structure on image configurations and critical-curve morphology. We find that uncorrelated LoS structure can shift the relative positions of lensed images by several arcseconds, introduces a $\sim 6\%$ scatter in the area of a cluster's primary critical curve, and changes the total critical area within 100$^{\prime\prime}$ of the cluster potential minimum by $16^{+20\%}_{-14\%}$ at a source plane redshift of $z_s=4$.

JWST has enabled new high redshift observations with 14 spectroscopically confirmed galaxies at $z > 10$ to date, leading to a need for high redshift, high resolution simulations to interpret these observations. We present the physical properties and mock observations of the galaxies in the Renaissance Simulations to add to the growing database of high redshift simulation data to guide and interpret observations. We find that they provide an accurate representation of the formation history of JWST's $z > 10$ discoveries and follow the trends observed in JWST galaxies but extended to lower masses. The stellar masses of the Renaissance galaxies range from $\approx 10^{3}$ to $10^8 M_{\odot}$ and overlap well with the $z > 10$ JWST galaxies with a stellar mass range of about $10^{7}$ to $10^9 M_{\odot}$. The simulated SFRs increase from $10^{-4}$ to $10^1 M_{\odot}yr^{-1}$, overlapping the JWST galaxies' lower SFRs in the range $1 - 20 M_{\odot}yr^{-1}$. These compact galaxies show minimal morphology change as their stellar masses increase with the majority of the half light radii between $1$ and $10$ pc and the majority of the half stellar mass radii around $0.1$ kpc; their Sersic indices vary between $0$ and $4$. The Renaissance galaxies are bluer and generally transition well into the absolute UV magnitudes of the JWST galaxies in the main sequence of galaxies. Overall, our simulations agree well with JWST's discoveries to date, making them a valuable tool in the continued effort to understand the high redshift Universe.

This work investigates the FeII emission in active galactic nuclei (AGN), combining observational data from optical and near-infrared (NIR) spectra of the prototypical FeII emitter IZw1 with state-of-the-art photoionization modeling. Using updated FeII atomic datasets (Smyth et al. 2019; Tayal & Zatsarinny 2018; Bautista et al. 2015), we explore a wide parameter space to determine the physical conditions of FeII-emitting regions in the broad-line region (BLR). Our results show that optical ($R_{\rm 4570}$) and NIR ($R_{\rm 1\mu m}$) FeII emission can be simultaneously reproduced under consistent conditions, with the best agreement obtained using the Smyth et al. (2019) dataset, for hydrogen densities of $10^{11.0}$ to $10^{12.0}$ cm$^{-3}$ and near-solar metallicity. We quantify, for the first time, the impact of Lyman-$\alpha$ fluorescence on the physical conditions of FeII emission in both regimes, revealing its dominant role in the NIR and, in contrast, highlighting the stronger influence of collisional processes in the optical. Additionally, for the first time, we compare optical and NIR FeII emission simultaneously with OI and the CaII triplet (CaT), reinforcing their connection to similar spatial regions and physical properties, as well as their usefulness as better proxies for optical FeII. Our findings support the idea of a vertical BLR structure, with NIR FeII and OI originating in less dense regions of the cloud than optical FeII and CaT.

Magnetic fields play a crucial yet complex role in star formation, while their connection between large-scale filamentary clouds and small-scale young stellar objects remains poorly understood. We present new continuum polarization observations from the JCMT, ACA, and ALMA that provide continuous magnetic field measurements from approximately 5 pc down to approximately 4000 au, tracing for the first time the evolution of field morphology seamlessly across all key scales within a massive star-forming system. Our polarization maps reveal multiple U-shaped magnetic field structures pointing toward the central protocluster, aligned with accreting filaments from parsec to subparsec scales and converging at the compact center. This morphology suggests an environment of colliding flows that drag magnetic fields and trigger massive protocluster formation. On approximately 4000 au scales, we identify compact U-shaped fields likely guiding the kinematics of streamers accreting onto dense cores. The increasing curvature of these U-shaped patterns is a direct measure of a growing magnetic field tension force, implying a magnetic field strength scaling index of 0.50 +/- 0.10. These results indicate that the field, possibly enhanced by large-scale flow collisions, becomes strong enough to regulate star formation, linking parsec-scale colliding flows, a subparsec hub-filament system, and the triggering of massive star formation.

Radio source detection and morphological classification are fundamental for exploiting the scientific potential of modern radio continuum surveys. However, the rapidly increasing data volumes and the wide diversity of radio morphologies make traditional visual inspection infeasible and pose significant challenges for automated source finding. We apply a transformer-based set-prediction detector (RF-DETR) to 150\,MHz continuum images from the LOFAR Deep Fields for instance-level source detection and morphological classification. The method is adapted to multi-frequency-synthesis images of interferometric data and trained with a morphology-driven scheme using five mutually exclusive classes. The model is trained on the ELAIS-N1 Deep Field, where it achieves high detection and classification performance ($\mathrm{F1}\simeq 91$ per cent), and is then applied without retraining to the other three LOFAR Deep Fields. Across all four fields, the model yields consistent catalogues with modest field-to-field differences arising from survey depth and calibration. Compared with widely used PyBDSF catalogues, RF-DETR recovers the majority of PyBDSF sources while representing classical multi-component radio galaxies as single source-level detections rather than fragmented Gaussian components. Artefact-affected and spurious detections are identified as explicit classes, allowing these detections to be distinguished from general astrophysical sources in the resulting catalogues. As external validation, RF-DETR recovers the majority of visually identified extended and giant radio galaxies in the LOFAR Deep Fields and assigns them predominantly to extended morphological classes. These results indicate that transformer-based detectors provide a practical, scalable, morphology-aware approach to source finding in deep radio surveys, with clear relevance for forthcoming facilities such as SKA-Low.

We present measurements of the mass-metallicity relation (MZR) and fundamental metallicity relation (FMR) at $1.4<z<7.0$ using stacked JWST/NIRSpec spectra of 601 star-forming galaxies from the JWST Advanced Deep Extragalactic Survey (JADES). Using the most up-to-date strong-line metallicity calibrations based on high-redshift galaxies, we derive gas-phase metallicities from composite spectra binned by stellar mass, redshift, and star-forming main sequence (SFMS) offset. We find that the MZR slope evolves weakly from $z\sim0$ out to $z\sim5$, with $\gamma\sim0.21\pm0.03$, while the normalization decreases smoothly with redshift at a rate of $d\log(\mathrm{O/H})/dz\sim-0.1$ out to $z\sim4$. Beyond $z\gtrsim5$, the low-mass end continues to decline in metallicity while the high-mass end remains broadly consistent with lower-redshift relations, producing a steeper overall MZR. We additionally find evidence for a shallow anti-correlation between deviations from the MZR and SFMS at fixed stellar mass at $z\sim1.4-5$. This anti-correlation, albeit with weaker SFR coupling than observed locally, suggests that an FMR is already beginning to emerge by $z\sim5$. Comparisons with recent observations and cosmological simulations show broad agreement, though no single simulation simultaneously reproduces the observed slopes and normalizations across all redshifts. Our results support a picture in which bursty star formation and strong stellar feedback increasingly shape the regulation of galaxy growth at high redshift, while also highlighting the need for substantially larger spectroscopic samples to robustly constrain the evolution of galaxy scaling relations at high-redshift.

We identify voids in NGC 628 from the JWST MIRI F770W image using a deep_learning method (BlendMask) and refine them by intensity contrast. These voids may be feedback_driven bubbles or dynamically formed structures. Cross_matching with archival star cluster/association catalogs shows that only up to 17.6% of voids are associated with such stellar populations. HST B_band peak_flux distributions of voids with and without these populations overlap substantially, suggesting many related clusters/associations remain unidentified or misclassified. Voids associated with star clusters/associations tend to have lower intensity contrast and larger sizes. An anti_correlation between void size and intensity contrast indicates larger voids have emptier centers, possibly due to stronger feedback. Thus, voids may provide a complementary tracer for identifying stellar populations and constraining their physical properties. To quantify spatial relationships among CO, 21$\mu$m, H$_{\alpha}$ sources, and voids, we construct networks linking each source pair. Among the nine networks, 21$\mu$m and H$_{\alpha}$ sources show the strongest spatial association. Compared to small voids, large voids exhibit progressively increasing separations from CO to 21$\mu$m to H$_{\alpha}$ sources to voids, consistent with an evolutionary sequence in space and time. Smaller voids lie closer to molecular clouds, while larger voids are more displaced. Compared with molecular clouds not associated with voids, those associated with voids are significantly more massive and appear more evolved. Indeed, 68% of molecular clouds associated with voids are also associated with 21$\mu$m sources. These results support an evolutionary scenario where some voids originate within molecular clouds, grow through stellar feedback, and gradually detach from their parent clouds.

We present three-dimensional general relativistic magnetohydrodynamics simulations of equal-mass binary neutron star mergers with varied neutron star spin configurations and second-moment neutrino transport, following the formation and early evolution of long-lived remnants. We compare a fiducial irrotational binary with binaries having spins that are aligned or antialigned with the orbital angular momentum, and examime how spin affects the merger dynamics, magnetic field evolution, outflows, and nucleosynthesis. Compared to the fiducial case, the aligned spin configuration releases more cold, neutron-rich tidal ejecta in the equatorial plane, which enables the development of a more tightly collimated polar outflow erupting from the remnant and inner accretion disk. Conversely, the case with spins antialigned with the orbit experiences a more violent collision at merger, disrupting magnetic amplification, loading the environment with debris, and impeding the propagation of magnetically driven winds. Strong neutrino reprocessing of the polar outflow in the irrotational and aligned spin cases produces $2.4\times 10^{-3}\,M_\odot$ of proton-rich ($Y_e \geq 0.49$) material, resulting in the synthesis of light r-process elements including $^{56}Ni$, whose subsequent decay potentially sends a unique electromagnetic signal from long-lived remnants. However, the outflows remain too dense and slow to be consistent with typical short gamma-ray bursts.

Direct imaging of exoplanets requires stellar coronagraphs capable of suppressing starlight to contrast levels below $10^{-8}$. Active wavefront control with deformable mirrors (DMs) is essential to create dark holes in the image plane. However, polarization aberrations arising from beam reduction optics and the coronagraph itself produces multiple non-interfering intensity components that have correlated responses to the DM. This article introduces the concept of gratis mitigation: when a control loop minimizes one intensity component, others can be reduced concomitantly due to the correlated DM responses. Using end-to-end physical optics simulations of a Lyot coronagraph fed by a 4 m-class telescope with $f/5$ beam reduction, we demonstrate gratis mitigation and analyze its origin via a Jones matrix formalism. Gratis mitigation has significant implications for coronagraph design, calibration, and possibly wavefront control.

Measurements of tangential drifts of distant quasars and galactic nuclei on the celestial sphere provide a novel and independent method of testing cosmological hypotheses. In this work, we employ an axisymmetric Bianchi I model as a relatively simple phenomenological model that is useful for quantifying departures from the cosmological principle. Using a quality-filtered sample of 1.2 million proper motion vectors of distant quasars from Gaia Data Release 3, we perform global fits of the position drift fields with vector spherical harmonics (VSH) to second degree for five non-overlapping subsets of the sources with redshifts from 0.5 to 3, and assess the ability of the Bianchi I model to describe the signal. We theoretically demonstrate that an axisymmetric Bianchi I model produces a signal that can be described as a single quadrupole VSH term with an eigendirection which is aligned with the axis of maximum expansion anisotropy. We estimate this preferred direction from the Gaia data and the VSH fit, and perform point-estimates of the amplitude of the signal as a function of redshift. Although a significant quadrupole signal is detected in each bin, the increase of the amplitude of the signal with redshift predicted by the Bianchi I model is not confidently confirmed. The estimated value of the local expansion shear is higher than expected. Possible advances in describing the kinematic patterns of a high-redshift Universe with more complex cosmologies accommodating time-dependent anisotropy and rotation are discussed.

As the largest and most recently formed stage of hierarchical structure, present-day galaxy clusters are predicted to have a broad range of late-time assembly histories. This diversity may explain much of the scatter in scaling relations and other cluster properties. Observationally, systems with more or less recent accretion should appear as unrelaxed and relaxed clusters, respectively. However, it is unclear which of the many possible structural measures best correlate with assembly history. Using the IllustrisTNG simulations, we explore the correlation between structural parameters and assembly history. To assess the effectiveness of different structural selection criteria, we define subsamples of the most and least relaxed clusters based on the values of various intrinsic, projected, and stellar structural parameters, and then compare the median assembly history of the subsamples in each case. We find that several observable quantities, including the magnitude gap between the brightest galaxies and the asymmetry of the stellar mass distribution, are very effective in selecting cluster samples with more or less recent accretion, even when applied in projection. Given the strong correlations between assembly history and present-day cluster structure, we suggest that structural classification be included explicitly in any analysis of catalogue completeness, scaling relations, or mean density profiles.

Wave-like dark matter ($\psi$DM) is an elusive dark matter (DM) candidate. The model, often also called fuzzy or ultralight DM, proposes that DM is an extremely light ($m\sim10^{-22}$ eV) boson and thereby has a kpc-scale de Broglie wavelength. Hence, interference of DM gives rise to sub-galactic density fluctuations that can be studied with strong gravitational lensing. In this paper, we use the residual power spectrum, $\mathrm{P}_{\delta}(k)$, as a probe of $\psi$DM, which quantifies deviations from smooth lensing predictions, measured from multiply-imaged galaxies in strong cluster lenses. The key idea is that imprinted in these deviations are lensing distortions from DM substructure, which can be harnessed statistically to distinguish among DM theories. We simulate JWST-quality mock observations of strong gravitational lensing in galaxy clusters, modeling line-of-sight DM substructure within $\psi$DM and the standard cold dark matter (CDM) paradigms. Using mock deep observations ($\sim$ 20 hours), we find that $\mathrm{P}_{\delta}(k)$ is sensitive to both $\psi$DM particle mass and fluctuation amplitude, and can distinguish $\psi$DM fluctuations from CDM subhalos. We demonstrate that $\mathrm{P}_{\delta}(k)$ can be measured directly from data by modeling the smooth lensing with a local Curved Arc Basis formalism. With realistic modeling systematics, we find a statistically significant separation between $\psi$DM and CDM across $1 \lesssim k \lesssim 11\,\mathrm{kpc}^{-1}$ -- offering an independent probe of the wave-like nature of DM complementary to existing constraints.

Weak CN absorption near ~8000 A has recently been detected in evolved red supergiants (RSGs) of 5-10 $M_\odot$ across three Local Group galaxies. These weak-CN RSGs sit in a narrow molecular regime: cool enough for CN to be visible in a non-carbon, C/O<1 atmosphere, but warm enough that TiO is not saturated and changes in $T_{\rm eff}$ and in the surface C+N reservoir move CN and TiO in distinct directions. We test this picture with pseudo-continuum equivalent widths (EWs) measured from LMC, M33, and M31 weak-CN and carbon-star coadds, compared at matched resolution to a self-consistent grid of synthetic RSG atmospheres spanning $T_{\rm eff}$, $[\alpha/{\rm Fe}]$, and surface C and N offsets relative to each host's scaled-solar baseline. Ordinary cool-RSG models reproduce the weak-CN coadds across all three hosts, with per-feature residuals at the level of the adopted EW systematic floors. The robust observable is the combined surface abundance $\Delta$[C/H]+$\Delta$[N/H] rather than each offset individually, because CN forms from the product of available C and N number densities. Mapping $\Delta$[C/H]+$\Delta$[N/H] to initial rotation through PARSEC v2.0 has modest leverage -- the variable shifts by ~0.07 dex from $\omega_i$=0 to $\omega_i$=0.6 -- and within this resolution slow-rotation first dredge-up is consistent with LMC and M33, and with M31 once a single-feature CaT 8542 A calibration anchor is allowed. The straightforward resolution of the discovery puzzle is therefore that weak CN is not an exotic carbon-star intermediate but the expected molecular-equilibrium signature of ordinary cool RSGs.

We present a detailed characterisation of radio frequency interference (RFI) in the 2.4 GHz band around Murriyang, CSIRO's Parkes radio telescope. The dominant sources of interference are Wi-Fi and Bluetooth transmissions. We quantify how the intensity and directionality of this RFI vary with time of day and document its evolution over several years. Although most observers currently discard data within this band, our analysis shows that the interference is confined in both timeand frequency and can be effectively mitigated. Using 10 seconds of 16-bit voltage data recorded during observations of the Vela Pulsar (PSR J0835-4510), we demonstrate that the majority of the channelised data remain unaffected by RFI. We compare three RFI detection and mitigation algorithms and evaluate their relative performance. All methods perform effectively, and any could be implemented in real time to enable productive use of this observing band. A real time implementation would allow the scientific use of this 128 MHz observing band to increase, from almost 70% of the band being completely unusable all of the time, to over 90% of becoming accessible for science. Given its simplicity and efficiency, a basic power-threshold approach offers a relatively straightforward solution.

We present an extended catalogue of 1193 Herbig-Haro (HH) objects, comprising 477 isolated HH objects and 716 HH knots, compiled through a meticulous review of the literature available through mid-2025. The catalogue provides comprehensive data for each entry, including celestial coordinates, distances, knot separations, exciting sources (with spectral types where available), object characteristics, and bibliographic references. We also perform a preliminary statistical analysis of key parameters such as distance, exciting source properties, morphology, and excitation state. By combining our extended catalogue with the two earlier HH object catalogues published by Hippel et al. in 1988 and Reipurth in 2000, astronomers can access comprehensive information on all known HH objects, thereby facilitating research on star formation and stellar outflows.

The distinct physical and geochemical differences between Earth and Mars provide fundamental constraints on terrestrial planet formation, yet a self-consistent framework linking dynamical and chemical aspects remains elusive. Here we present an integrated modeling framework that couples high-resolution N-body simulations with impact-driven metal-silicate equilibration to track the dynamical accretion history and chemical differentiation for Earth and Mars. Using a narrow ring planetesimal accretion scenario, we show that Earth and Mars analogs naturally sample systematically different solid reservoirs within the protoplanetary disk. Earth analogs preferentially accrete reduced material around the planetesimal ring center, whereas Mars analogs acquire a larger fraction of oxidized material exterior to the ring. This leads to diverse bulk redox states, with composition further modified by impact-dependent pressure-temperature equilibration conditions during core formation. As a result, Earth analogs experience deeper equilibration and more efficient transfer of iron into the core, producing mantles with low iron oxide contents and larger core mass fractions. In contrast, Mars analogs equilibrate at shallower conditions, retain more iron in their mantles, and develop smaller cores. Our results demonstrate that the dynamical and geochemical differences between Earth and Mars emerge from the coupled effects of accretion pathways, the disk's radial redox structure and impact-controlled differentiation, rather than from any single process. Our unified framework physically explains the geochemical diversity of terrestrial planets and offers a potential pathway to interpret compositions of rocky planets in exoplanetary systems.

The James Webb Space Telescope (JWST) has revolutionized the characterization of exoplanetary atmospheres, offering unprecedented sensitivity to probe their chemical and physical properties. Recently, a growing trend has emerged to obtain atmospheric information directly from pixel-level planetary spectra. In this work, we re-analyzed the WASP-18b NIRISS/SOSS dataset by employing a direct extraction method. This new method preserves the spectral information at the native instrumental resolution, thereby enabling the application of cross-correlation techniques and providing atmospheric retrievals with enhanced precision and richer information content. With this methodology, we report detections of CO at $4.4\sigma$ significance, H$_2$O at $3.4\sigma$, and OH at $7.8\sigma$, where CO and OH were previously unseen. Building on these unambiguous detections, our subsequent retrieval analysis significantly improves the constraints on atmospheric abundances. Our results demonstrate that the cross-correlation technique effectively extracts molecular signals from medium-resolution JWST data, enhancing detection sensitivity. By revisiting JWST archival data with cross-correlation and retrieval analysis, we can achieve a more comprehensive survey of planetary atmospheric chemistry, thereby placing precise constraints on key parameters such as planetary metallicity and C/O ratio.

Interstellar scintillation probes the properties of the ionized interstellar medium as well as the dynamical behavior of pulsars themselves. Using the Five-hundred-meter Aperture Spherical Radio Telescope, we obtained hour-long observations of PSRs~J0837+0610, J1136+1551, and J1239+2453. We detected a single scintillation arc in PSRs~J0837+0610 and J1239+2453, and identified three distinct arcs in PSR~J1136+1551. Our analysis reveals that the arc curvature scales with observing frequency as $\eta \propto \nu^{-2.0\pm0.6}$ for PSR J0837+0610, and as $\eta \propto \nu^{-1.9\pm0.6}$ for PSR J1239+2453. For PSR J1136+1551, the two clearest arcs exhibit scaling relations of $\eta \propto \nu^{-1.6\pm0.6}$ and $\eta \propto \nu^{-2.0\pm0.4}$, respectively. However, the frequency dependence of the third arc could not be constrained due to its low signal-to-noise ratio at higher frequencies. Moreover, the corresponding scattering screens are measured at distances ranging from 30 to 420 pc from Earth. However, long-term scintillation monitoring or VLBI observations are needed to reliably measure the scattering screen.

Local structures in the Universe can influence the dynamics of light scalar fields when coupled to matter. We focus on light test fields evolving in matter modelled as a stochastic source. We describe the effective field theory for light scalars on large scales after integrating out the short distance dynamics. This is most conveniently performed in the Schwinger-Keldysh formalism where we find that the large distance theory involves a stochastic noise corresponding to the exchanges between short and large scales, and new interactions which can affect the time evolution of light scalars. We exemplify this back-reaction when the coupling between matter and scalars is small leading to corrections to the Klein-Gordon equation of the light scalars on large scales. In particular, the resulting corrections to the scalar potential could lead to effects akin to dynamical dark energy. We also consider the situation where all the substructures of the Universe are screened leading to the suppression of large scale dynamics and a cosmic Meissner effect. This highlights the potentially relevant effects of small scale structures on the cosmological dynamics of light scalar fields.

The simplest models of slow-roll inflation predict a featureless, nearly scale-invariant power spectrum of primordial curvature perturbations, consistent with current observations. However, in many non-minimal realisations of inflation, one generically expects the primordial power spectrum (PPS) to be ''wiggly'' with features that strongly deviate from scale-invariance. Current and next generation large scale structure (LSS) surveys will probe the PPS with unprecedented accuracy and therefore also increase sensitivity to power spectrum wiggles. However, accessing the information contained in these data will require an understanding of the behaviour of wiggly power spectra beyond the linear regime of structure formation. In this work, we use high resolution $N$-body simulations to study the non-linear evolution of scenarios in which the PPS has superimposed oscillations, calibrate a one-parameter semi-analytic damping model to describe their signatures in the late-time matter power spectrum and test the relative improvement on constraints by implementing this modelling strategy in a likelihood analysis via Gaussian Process Regression (GPR) emulation. Paying special attention to identifying our approach's domain of validity and quantifying as well as propagating uncertainties, we demonstrate that as long as the frequency of the PPS modulation is large enough, we are able to predict the matter power spectrum with sub-percent accuracy -- thereby enabling us to search for inflationary wiggles in LSS data.

We investigate how galaxy evolution varies with environment in the nearby Universe by comparing an ``average'' reference volume in the Southern Galactic Pole (SGP) dataset from \citet{VanKempen2024} to the Nexus region, a dynamically assembling superstructure centred on the Abell~4038 galaxy cluster. We quantify environmental effects using the quenched fraction ($f_{\mathrm{Q}}$) and the specific star formation rate ($\mathrm{sSFR}$) for the star-forming population, measured as functions of stellar mass and group-scale halo mass from \citet{VanKempen2026}. We decouple the stellar--halo mass dependence, demonstrating that $f_{\mathrm{Q}}$ increases with stellar mass in both field and group environments, while group galaxies show an additional dependence on halo mass. The Nexus exhibits systematic differences relative to the SGP baseline, consistent with increased heterogeneity in accretion histories and pre-processing within a forming superstructure. For star-forming galaxies, the mean $\log(\mathrm{sSFR})$ declines strongly with stellar mass and shows additional environment-linked suppression in group-scale halos. Within the Nexus, splitting the sample into three projected radial zones around Abell~4038 shows that environmental regulation is not spatially uniform, driven largely by variations in the sampled halo mass function. Finally, a projected phase-space (PPS) analysis of Abell~4038 links quenching to orbital history within the cluster, though this trend is strongly mass-dependent: low-mass galaxies ($\log(M_{\mathrm{stellar}}) < 10$) show no significant change in $f_{\mathrm{Q}}$. These results demonstrate that the drivers of galaxy evolution depend jointly on stellar mass, local group halo mass, and location within the surrounding large-scale structure, motivating future large-scale, multi-wavelength cosmic web surveys.

We construct Pulsar Polarisation Arrays (PPA), using regular pulsars monitored in MeerKAT's Thousand Pulsar Array (TPA) Programme, to search for Axion-like Dark Matter (ALDM) within Milky Way. Specifically, from a catalogue of 1237 regular pulsars, we select the 50 ones with the highest signal-to-noise ratio and set upper limits on the ALDM Chern-Simons coupling. We find no signals with statistical significance over the mass range of $[10^{-23},10^{-20}]\,{\rm eV}$ in the six-year MeerKAT's data. By combining the high-quality TPA pulsars and the accurate ionospheric subtraction of spinifex, we establish the most sensitive upper limits to the date on the ALDM Chern-Simons coupling, namely $\lesssim 10^{-14} - 3\times 10^{-13}\,{\rm GeV}^{-1}$, for the mass range of $[10^{-23},10^{-21}]\,{\rm eV}$ except at $m_a \sim 1.3 \times 10^{-22}\,$eV. This study underscores the great potential of constructing regular-pulsar PPAs for scientific tasks.

Early ($z \gtrsim 2$) Massive ($M_{\star} \gtrsim 10^{10}\,\mathrm{M_{\odot}}$), Quenched Galaxies (MQGs) challenge current galaxy formation models. In this series, we study these systems using the new COLIBRE cosmological hydrodynamical simulations. Following the broad agreement between its predictions and observations found in the first paper, this second paper explores the processes driving galaxies to become massive and quenched in COLIBRE, identifying Active Galactic Nucleus (AGN) feedback as the primary quenching mechanism in both the thermal (L200m6 simulation) and hybrid (thermal+jet, L200m7h simulation) AGN feedback models implemented. However, the two models behave differently: while the thermal model efficiently quenches massive galaxies at $z>3$, the hybrid model is less effective because black holes (BHs) grow more slowly in the early Universe, and the jet component, which dominates the feedback energy, acts on longer timescales to impact galaxies. Both models predict quasar-like MQGs (AGN with $L_{\rm bol}\gtrsim10^{45}\,\mathrm{erg\,s^{-1}}$), with the most luminous systems associated with more recently quenched galaxies. Compared to star-forming galaxies of similar mass, MQGs host more massive BHs and exhibit higher star formation efficiencies. These differences arise primarily from their environments before quenching, particularly at local ($\rm 0.3\,cMpc$) to intermediate scales ($\rm 1.0\,cMpc$), where overdense regions are associated with enhanced gas inflows, higher BH accretion and, hence, feedback power. We find that about $54\%$ ($20\%$) of the $z=3$ MQGs survive as the main progenitors of $z=0$ galaxies, although up to $56\%$ ($60\%$) experience rejuvenation episodes at $z<3$ in L200m6 (L200m7h). Our results highlight the central role of BH growth, AGN feedback and environment in driving rapid quenching in the early Universe.

The HD 81809 system presents peculiar chemical composition with a large metallicity difference between its two components: the primary has low metallicity ([Fe/H]=-0.57 dex), while the secondary has approximately solar metallicity ([Fe/H]=0.0 dex). This study investigates whether the chemical enrichment of HD 81809B can be reconciled by a planetary engulfment event, consistent with the star's evolutionary constraints. Using Modules for Experiments in Stellar Astrophysics (MESA) code, we model HD 81809B introducing accretion events with different ranges of masses and chemical mixtures to understand their impact in the surface chemical composition. Our simulation shows that reproducing the observed surface [Fe/H] in HD 81809B requires a substantial accretion event. To reach the observed metallicity, the star must engulf 25 to 75 $M_\oplus$ of metals near its current age. Accretion brings the effective temperature of stellar models closer to the observed one; however, the lithium results over-enriched. In order to reproduce the abundance of this element, the star must accrete less than 6 $M_\oplus$. These results suggest that a planetary accretion event is plausible in the evolution of HD 81809B; however, the chemical composition of the accreted material may differ from the assumptions adopted here. Nevertheless, this study emphasizes the importance of considering such external events when modeling chemically anomalous binary systems.

In a recent paper, Chen et al. developed a framework for modeling the seeding and growth of supermassive black holes (BHs) in the context of $\Lambda$CDM cosmogony. Here, we use a set of physically motivated criteria to select a population of predicted BHs and link them to Little Red Dots (LRDs) discovered by JWST. We show that the LRD population at high redshift ($z$) emerges naturally from a subset of BHs with super-Eddington accretion during nuclear bursts. The model suggests that the observed LRDs are the "tip of the iceberg" of a much larger population of less luminous BHs in the same subset. The model makes specific predictions for the LRD population, such as the mass distributions of their BHs and host galaxies/halos, and the piece-wise redshift evolution of their number density. The cosmological context of the model also allows us to link the observed LRD population to their progenitors (their BH seeds) and lower-$z$ descendant BHs, galaxies and halos. Most LRDs at $z\sim 5$ are seeded at $z \gtrsim 20$ through direct-collapse BHs or pair-instability supernovae from Pop-III stars, and have grown to $M_{\rm BH} \approx 10^5$--$10^7\,{\rm M}_\odot$ through nuclear bursts by their observed redshift. LRDs are predicted to have diverse descendants, ranging from compact dwarf galaxies to brightest cluster galaxies (BCGs) at $z=0$. These predictions are consistent with current observations and can be further tested. The success of this model indicates that the results presented here provide a robust foundation for building detailed models of the LRD population.

The present-day solar system comprises meteorites with varying oxidation levels, derived from different parent bodies. Previous studies (e.g. Rubie et al., 2011) of the partitioning of siderophile elements between mantle and core during planetary growth and differentiation showed that Earth must accrete reduced bodies first and oxidised bodies later. Here we show that, if the terrestrial planets formed from a narrow ring of planetesimals, this condition is not fulfilled, whatever heliocentric gradient of oxidation is assumed in the ring. The reason is that planetary embryos quickly accrete planetesimals from the whole width of the ring, incorporating both reduced and oxidised material. The partially oxidised state of all planetary embryos leads to mismatches with the composition of the bulk silicate Earth (BSE) because oxygen fugacity strongly affects the partitioning of siderophile elements. We demonstrate that reproducing the BSE composition requires reduced and oxidised reservoirs to remain segregated until embryo formation is almost complete. The delivery of oxidised material to the terrestrial planet-forming ring towards the end of the disc's lifetime is therefore a key requirement of any successful dynamical model of terrestrial planet formation.

Extreme gamma-ray transients represent some of the most energetic and physically constraining phenomena in high-energy astrophysics. They are characterized by rapid, large-amplitude variability and by physical conditions approaching fundamental limits on particle acceleration, cooling, and compactness. In this review, we focus on transients detected above around 100 MeV and define extreme events as either those involving catastrophic transformations of astrophysical systems (such as stellar explosions, compact-object mergers, and tidal-disruption events) or those exhibiting evidence for particle acceleration operating in an extreme regime. These systems are powered by the rapid release of gravitational, magnetic, nuclear, or kinetic energy, with shocks and magnetic reconnection playing a central role in producing ultra-relativistic particle populations and non-thermal radiation. We summarize observational and theoretical diagnostics that constrain the size, magnetization, and Lorentz factor of the emitting region, including variability timescales, luminosity-timescale correlations, and spectral evolution across the MeV-TeV domain. We further review the complementary capabilities of space-borne gamma-ray instruments, ground-based Cherenkov and air-shower observatories in detecting short-lived, high-energy outbursts. Extreme transient classes discussed include gamma-ray bursts, novae, rapidly variable emission from extragalactic and Galactic jets. Also, because of its extreme aspects, we include flaring emission detected from the Crab Nebula. While each type of these flares poses interesting challenges for phenomenology and theory of these sources, together, these events form the landscape of extreme gamma-ray variability.

The chemical composition of a protoplanetary disc is sensitive to its thermal structure and dust properties, and can provide insights into the disc evolution. Recent observations with the James Webb Space Telescope (JWST) reveal correlations of the inner disc compositions with disc size, accretion rate and stellar mass, explained by the key role of dust radial drift in redistributing primordial volatiles. We explore how chemical reactions change the composition of ices carried with pebbles and how they affect the inner disc C/O ratios in a disc around a solar mass star. We consider different drift efficiencies set by dust fragmentation velocity and include dust traps at different locations. We vary the incident cosmic ray ionisation rate $\zeta$ and the efficiency of cosmic ray dissociation of ices, and consider the effect of carbon grain destruction. We find that methane depletion within $<1$ Myr prevents the delivery of carbon-rich gas to the inner disc and yields $\mathrm{C/O} \lesssim1$ for $\zeta\geq10^{-17}$ s$^{-1}$. Dust traps collect water and carbon-rich ices formed via methane destruction, further lowering the inner disc metallicity and C/O ratio. Cosmic-ray driven photodissociation of ices can convert water to O$_2$ and carbon-bearing molecules to CO, allowing ices to escape the trap if $\gtrsim10 \%$ of the dissociated products can participate in surface reactions. We discuss the observational implications and conclude that cosmic rays and their effect on ices are the key factors that determine the impact of chemistry on the inner disc composition.

Context. This article presents a detailed multi-wavelength analysis of GRB 140304A at z = 5.282, having uncommon late-time flaring features. The aim is to study GRB 140304A and other similar bursts to understand stellar evolution and formation processes at high-z. Aims. GRBs at high-z, possible flaring activities at different frequencies seen at relatively late-times, help to constrain temporal correlation among contemporaneous flares. In the present study, we plan to constrain such a temporal and spectral study for a sample of high-z bursts, including GRB 140304A. Methods. We use Swift, Fermi, and ground-based observations to constrain the temporal and spectral properties of the prompt and afterglow emissions. Using the cross-correlation function, we calculate the spectral lag in the light curves observed in two energy bands of Swift's Burst Alert Telescope (BAT) and X-ray Telescope (XRT). Results. Parameter evolution of the prompt emission analysis reveals a hard-to-soft evolution of the spectral peak energy (Ep) and the magnetic field strength (B), consistent with the typical population of long GRBs. For GRB 140304A, a rare pattern of spectral lag evolution having positive lag in the early BAT light curves, but no lag is observed in the XRT light curves. We have also observed systematic time delays among the peak times of flares in three different bands, but the optical flares exhibit a morphological correspondence with X-ray or gamma-ray flares. Conclusions. Our analysis shows that the observed positive spectral lag in GRB 140304A is closely related to the hard-to-soft spectral evolution during the prompt emission phase, as seen in some of the other long GRBs. Additionally, there is a clear connection between gamma-ray, X-ray and optical flares with prompt emission, which are produced through synchrotron radiation during rapid bulk acceleration within the emitting region.

We present the first application, to the best of our knowledge, of Physics-Informed Neural Networks (PINNs) to the neutron star equation-of-state (EOS) inverse problem. Two interacting networks -- one representing the EOS $P(\varepsilon)$ as a continuous, non-parametric function, the other solving the Tolman-Oppenheimer-Volkoff (TOV) equations -- are trained jointly on NICER X-ray timing posteriors and pulsar mass measurements. The TOV equations enter as a mean-square ODE residual enforced via automatic differentiation at every training step, rooted in the Neural Differential Equation framework. The inferred EOS satisfies nuclear saturation properties, causality, and perturbative QCD bounds simultaneously; $\chi$EFT consistency at $1$--$2\rhoz$ emerges without explicit enforcement, providing a non-trivial self-consistency check. Across $N=15$ independent training runs, we find a neutron star maximum mass $M_\mathrm{max}=2.06^{+0.07}_{-0.09}$ and radius and tidal deformability of a 1.4 $M_\odot$ star $R_{1.4}=12.85^{+0.03}_{-0.06}$~km and $\Lambda_{1.4}=684$, respectively, with 68\% CI, in agreement with recent Bayesian analyses. Most interestingly, the speed of sound exhibits a reproducible softening at $2$--$4\,\rhoz$, consistent with a quark-hadron crossover.

Mass transfer is arguably the most defining interaction in binary stellar systems, yet many aspects of its physics remain poorly understood, from stability to endpoints and observable products. Comparing theory and observations is challenging because post-mass-transfer systems are studied across largely independent communities with different methods, nomenclature, and evolutionary frameworks. % We present a unified review and catalog of ongoing and post-mass-transfer binaries spanning the full stellar mass range, but restricted to systems likely to have experienced only a single episode of mass transfer (i.e., only one component is evolved). We review 16 observational classes of binary interaction products and compile a curated sample of 5,452 systems into a publicly available, community-driven catalog at this https URL. % Using this catalog, we investigate global trends in orbital periods, eccentricities, masses, and mass ratios across post-mass-transfer binaries. We find I) non-zero eccentricities are common at all periods and system classes, with both median values and scatter increasing with period, II) the $e(\log P)$ relation depends on donor progenitor mass, with neutron-star and black-hole binaries showing the highest median eccentricities, likely reflecting effects of natal kicks, III) period distributions are broad and overlapping across evolutionary channels, and IV) the Gaia BH and NS systems are extreme in mass ratio but otherwise consistent with the general post-mass-transfer population. Together, these results support a unified empirical view of post-mass-transfer binaries that highlights several tensions between theory and observations.

Processing astronomical data can take up a significant amount of researchers' time. The 80cm telescope at Xizang University is currently in its trial operation phase; however, it lacks a data processing program, which makes efficient handling of the data it generates an urgent concern. To address this issue, we have developed an automatic pipeline for processing photometric data and extracting light curves using Python 3. This pipeline has several advantages, including high speed, ease of use, and modularity. The differential photometric accuracy of this pipeline is comparable to that of data processing programs used by other similar telescopes. This development effectively overcomes the limitations of manually processing data, providing efficient and reliable support for future studies of variable stars. The pipeline has already been integrated into the telescope's operational system.

Time-reversed stochastic inflation solves the stochastic evolution of the inflationary universe backward in time, by counting the number of e-folds from the end of quantum diffusion towards some initial state. The point of view of observers attached to the end-of-inflation hypersurface is thus enforced. In this work, we exactly solve time-reversed stochastic inflation in a flat and bounded potential, the so-called quantum well. At given lifetime, the field behaviour is found to be either indistinguishable from the one obtained in a semi-infinite flat potential, or, subject to enhanced stochasticity where any memory of the initial state is erased. The derived distribution of curvature perturbations reduces to the semi-infinite result for small fluctuations while it develops exponential tails for the large ones. Such tails arise for both positive and negative values, and decay twice as fast as the one obtained in the standard forward stochastic inflation. These differences may have important consequences for tail-sensitive phenomena, such as primordial black hole formation.

We perform a stress test of gravothermal collapse in self-interacting dark matter (SIDM) halos under baryonic feedback using a semi-analytical oscillating-potential model in controlled N-body simulations. For high-concentration halos, where the SIDM thermalization timescale is short, gravothermal collapse is only mildly delayed and never stalled, even under extremely strong feedback. In contrast, the collapse of a median-concentration halo can be significantly delayed, but it resumes once feedback ceases. The final density profile of such halos depends sensitively on the episodic feedback history, producing a broad diversity in central densities. These results strengthen the interpretation of dense compact perturbers identified in recent strong-lensing observations as core-collapsed SIDM halos.

The knee feature in the cosmic-ray energy spectrum around 4 PeV is widely believed to have a Galactic origin, but the acceleration mechanism and identification of PeVatrons remain key open questions in high-energy astrophysics. Recent precise measurements by LHAASO reveal that the proton and helium spectra exhibit a common rigidity-dependent spectral break at ~ 3.5 PV, imposing a stringent constraint on source models. In this work, we construct, for the first time, a time-dependent cosmic-ray injection model that incorporates the full evolution of massive stars together with the dynamical development of wind termination shocks. We find that stellar winds of individual massive stars cannot explain the common spectral break observed by LHAASO, as they yield distinct rigidity cutoffs for protons and helium. By contrast, collective winds of massive star clusters naturally reconcile this discrepancy through the mixing effect of stars at different evolutionary stages. We propose a stellar-dominated model in which supernova remnants dominate the GeV-TeV range, individual stellar winds dominate the TeV range, and collective cluster winds dominate the PeV knee region. This model successfully reproduces the rigidity-dependent spectral features of various species near 100 GV and 0.1 PV. It further makes two testable predictions for future observations. Around 0.5 PV, the energy spectra of carbon and oxygen are expected to exhibit hardening similar to that of helium, which can be verified by LHAASO observations. In the multi-TV range, the energy spectrum of magnesium is not expected to show hardening similar to that observed for helium, carbon, and oxygen, which can be tested by DAMPE observations.

The Gaia Data Release 3 (GDR3) parallaxes are affected by a complex bias that depends on stellar magnitude, color, and celestial position, with amplitudes reaching tens of microarcseconds ($\mu$as). Standard global parametric models (e.g., Lindegren et al. 2021, hereafter L21) effectively remove large-scale trends but struggle to resolve small-scale spatial systematics due to functional rigidity. We aim to construct a flexible, data-driven calibration map that eliminates these residual local systematics without imposing rigid functional forms. We propose a "Global Pre-correction + Local Refinement" hybrid strategy. First, we utilize the L21 model as a baseline to remove the dominant magnitude and color-dependent biases. Second, we model the residual zero-point using a Local Non-parametric method based on a Sliding Window technique. This approach fits local trends using k-nearest neighbors from quasars (for faint stars, G>18) and wide binaries combined with Large Magellanic Cloud (LMC) (for bright stars, G < 18). Our hybrid model demonstrates significant improvements over the standard L21 solution. Validation against different samples reveals a remarkably flat residual map with near-zero bias across the full sky. Our mathematical attempt at calibrating the parallax zero-point is expected to provide a useful reference for the zero-point correction in future Gaia DR4, and to help move towards a physical resolution of this issue.

Although globally-integrated studies often find that, at fixed stellar mass, high star formation rate (SFR) galaxies are relatively metal-poor while lower-SFR systems are more metal-rich, the corresponding coupling between gas-phase metallicity ($Z_{\rm gas}$) and star formation on sub-galactic scales remains poorly constrained. In this study, we analyse 14 Virgo spirals from the MAUVE-MUSE survey to revisit the resolved mass-metallicity relation (rMZR) and its secondary dependence on SFR surface density ($\Sigma_\mathrm{SFR}$) at $\sim 100$\,pc scales. We construct co-spatial maps of stellar mass surface density ($\Sigma_*$), $\Sigma_\mathrm{SFR}$, and oxygen abundance. MAUVE-MUSE galaxies follow a standard rMZR, but when binned by $\Sigma_*$, we find a mass-dependent inversion in the $Z_\mathrm{gas}$-$\Sigma_\mathrm{SFR}$ relation using O3N2 calibrations: the standard anti-correlation is confined to low-$\Sigma_*$ bins, while high-$\Sigma_*$ regions show a positive correlation, inverting at $\log_{10}(\Sigma_*/M_\odot\,\mathrm{kpc}^{-2})\simeq 7.5$-8.0. Correlated and anti-correlated \ion{H}{ii} regions coexist within the same discs; the mass dependence emerges only when grouping spaxels by $\Sigma_*$. We develop a spatially resolved gas-regulator model showing this $Z_\mathrm{gas}$-$\Sigma_\mathrm{SFR}$ (anti-)correlation arises from competition between star-formation-driven and gas-supply-driven variability. This framework naturally extrapolates to the integrated scenario, providing a unified explanation for resolved and global relations. However, the presence and strength of the $Z_\mathrm{gas}$-$\Sigma_\mathrm{SFR}$ (anti-)correlation depend strongly on the metallicity indicator used, highlighting the challenge of disentangling physical secondary trends within metallicity scaling relations.

We present the evolution of galaxy size and surface brightness in the rest-frame $J$ band (1.22 $\mu$m), tracing the stellar mass distribution, over $0.5 \leq z \leq 3$, using a sample of 15,420 galaxies with stellar masses $M_\star=10^{10}$-$10^{11.5}\ M_{\odot}$ from the JWST COSMOS-Web survey. The rest-frame $J$-band effective radius ($R_{e,J}$) is obtained from previous measurements and mapped from the available JWST/NIRCam filters, while the surface brightness ($\mu_J$) is corrected for dust extinction and cosmological dimming. At a characteristic mass of $M_\star = 5 \times 10^{10}\ M_{\odot}$, star-forming galaxies exhibit a size evolution of $R_{e,J} \propto (1+z)^\beta$ with $\beta = -0.92 \pm 0.04$, falling between previously reported shallower and steeper measurements. Quiescent galaxies evolve more rapidly, with $\beta = -1.34 \pm 0.05$, consistent with earlier studies. Among star-forming galaxies, lower-mass systems ($10^{10}$ to $10^{10.5}\ M_{\odot}$) show slower ($\beta=-0.66\pm0.02$) size evolution compared to their higher-mass counterparts. Furthermore, the surface brightness brightens toward higher redshifts, scaling as $\mu_J \propto -2.5 \log(1+z)^\gamma$. We find $\gamma = 3.07 \pm 0.08$ for star-forming galaxies and $\gamma = 3.70 \pm 0.08$ for quiescent galaxies. We also find that massive star-forming galaxies ($M_\star > 10^{10.5}\ M_{\odot}$) exhibit similar $\mu_J$ values at fixed redshift, independent of mass. Finally, we demonstrate that the observed surface brightness evolution is driven by the combined evolution of galaxy luminosity and size.

In this third study of the series, we extend our U-Net Variational Autoencoder-based galaxy classification framework to a significantly larger JWST sample spanning the redshift range $0.5 < z < 4$. Focusing on massive systems with stellar masses exceeding $10^{10}\,M_\odot$, we analyze 1,380 galaxies that satisfy these criteria and apply our previously developed denoising and classification pipeline to identify disk-like morphologies across cosmic time. Within this population, our classifier detects 382 disk-like galaxies, with a subset showing uncertain features consistent with the expected performance limits of current deep-learning models. This expanded dataset allows us to examine the distribution of disk-like systems in a statistically meaningful high-redshift regime, including epochs where well-ordered disks are traditionally expected to be rare. The results demonstrate that disk-like structures persist across a broad range of redshifts and stellar masses, suggesting that massive disks may be more common in the early universe than previously assumed. These findings emphasize the value of combining advanced denoising techniques with machine-learning-based morphological analysis for characterizing galaxy populations in large JWST surveys.

Open clusters gradually dissolve, and their stars disperse into the Galactic field. Lost stars form tidal tails-elongated streams that trace the cluster orbit ahead of and behind its core. From the shape and orientation of the tidal tails, it is possible to infer the shape of the gravitational potential governing the cluster's motion. The orbits of open clusters, including those in the Solar neighbourhood, are sensitive to the gravitational potential of the inner Galaxy, which is dominated by the Galactic bar. Using n-body simulations of synthetic and real open clusters, we investigate how sensitive the shapes and orientations of tidal tails are to variations of the gravitational potential of the Milky Way. We consider the effects of the bar as well as spiral arms, giant molecular clouds (GMCs) and satellite galaxies. We analyse the stellar distributions within tidal tails using statistical metrics that quantify the differences between tail morphologies. Such non-parametric approach enables us to efficiently explore tidal tails across a large parameter space of gravitational potential models. We find that the Galactic bar-particularly its pattern speed-has a strong influence on the orbits of open clusters and the shape of their tails. Spiral arms have a limited effect, and satellite galaxies do not disturb the tidal tails of nearby open clusters. Perturbations by GMCs affect most clusters, with distortions stronger than those by the bar observed in old and in-plane clusters. We identify nearby open clusters that are most sensitive to the pattern speed of the bar. By observing the tidal tails of a handful of well-selected nearby clusters, we should be able to measure the pattern speed of the bar with a precision in the order of $1\ \mathrm{km\,s^{-1}\,kpc^{-1}}$ independently from length and orientation of the bar. We will present the observability of tidal tails in paper II.

Solar radio noise storms are common phenomena, composed of broadband continuum emission embedded with diverse fine structures, yet their unusually compact apparent sizes remain unexplained. We present frequency-time-resolved imaging spectroscopy of a near-disk-center noise storm observed by LOFAR between 30--40 MHz, together with anisotropic radio-wave scattering simulations. The continuum forms a bright, spatially compact source that drifts across the solar disk over tens of minutes. Across the band, the measured apparent major axis is $\sim8.0^\prime$ to $\sim4.3^\prime$ between 31.3 and 38.4~MHz, less than half the size of typical type III burst sources at comparable frequencies. Embedded type I bursts, S-bursts, and spikes exhibit a range of dynamic spectra appearances, yet share nearly identical apparent sizes within uncertainties, suggesting a common size-determining mechanism. Using anisotropic scattering simulations, we show that compact apparent source sizes naturally arise for emission embedded within closed magnetic field structures, where anisotropic turbulence directs radiation away from the observer's line of sight. Additional modifications arise from enhanced coronal densities, steeper density gradients, reduced turbulence levels, and strong fluctuation anisotropy, but these exert secondary influence. Our results provide a unified explanation for the similar apparent sizes of diverse fine structures in noise storms, and demonstrate that the compactness of type I storm sources is governed primarily by the large-scale coronal environment rather than intrinsic differences in emission processes, where the magnetic topology plays a crucial role in determining the observed source size.

Exoplanet demographic studies rely on large and homogeneous catalogs, yet stellar multiplicity remains incompletely characterised in many planet samples. Misidentified stellar companions can bias both stellar and planetary parameters, leading to ambiguous and incomplete conclusions about planet formation and evolution. We aim to construct a robust and reliable reference catalog of S-type exoplanets for future investigations of planet formation and evolution in multiple-star environments, and to reassess exoplanet demographics by comparing planets hosted by single-stars and binary systems in a statistically consistent framework. We update the PlanetS catalog of transiting exoplanets by systematically identifying gravitationally bound stellar companions using Gaia DR3. Adopting a deliberately conservative classification, we distinguish binary and single-star systems and constructed a matched control sample of single hosts to mitigate selection and observational biases. Using this curated dataset of 860 transiting exoplanets including 133 S-type planets, we performed a comparative demographic analysis of planetary properties as a function of host multiplicity, stellar mass, and binary separation. We find a binary fraction of 19.4% relative to the control sample (15.5% relative to the full single-star sample), consistent with previous estimates but derived from a larger and more homogeneous dataset. Significant demographic differences emerge in the giant planet regime, less affected by observational biases. We find that giant planets in binaries tend to be more massive than their single-star counterparts and to orbit closer to their host stars, making their radius more inflated. In particular, we identify a tentative excess of giant planets orbiting M-dwarfs in binaries with separations < 1000 AU, suggesting a potentially informative regime for future demographic studies.

Harmonics in pulsating stars have traditionally been regarded as mere Fourier artifacts, fully determined by their parent mode. Recent observations of high-amplitude $\delta$ Scuti stars, however, have revealed the existence of disharmonized harmonics, which exhibit amplitude and frequency variations uncorrelated with their parent pulsation mode. Here we test the universality of this phenomenon by examining a class of stars long considered pulsationally stable: non-Blazhko RRab stars. Using short-cadence {\it Kepler} photometric data, we not only identify a distinct hump structure formed by harmonics of the primary pulsation mode in their frequency spectra, but also find significant amplitude and frequency variations associated with the harmonics around the onset and in the tail of the hump structure. These findings are consistent with the interpretation that the hump structure originates from the turbulent convective envelope of the star. Interestingly, several important phenomena can be understood within this framework as a working hypothesis. Thus, the hump structure of harmonics and their intrinsic variability could constitute a hidden window into the stellar convective envelope, potentially tracing energy injection at the convection-pulsation interaction and stochastic perturbations from turbulent convection -- although detailed modeling is required to confirm this interpretation.

In this paper, we present an archival search for short gamma-ray bursts (sGRBs) over 13 years (2013-2025) of Fermi/GBM data using a Poisson matched-filter pipeline that performs a fully coherent analysis across all detectors and energy channels, significantly improving sensitivity relative to the onboard triggering algorithms. A central component of the analysis is the empirical estimation of trigger significance using 'timeslided' data, allowing each candidate to be assigned a probability of astrophysical origin. We also developed a new parameter-estimation framework based on the Poisson matched filter, which uses the global structure of the detected event across spectral, temporal, and spatial parameter spaces. This enables us to systematically classify bursts and distinguish between GRBs, soft gamma repeaters, terrestrial gamma-ray flashes, and solar flares. We identify 568 new GRB candidates with $p_{\text{astro}}\geq0.9$ and thousands of magnetar bursts, significantly expanding the known short-transient population in GBM data. To further strengthen the significance of the GRB candidates, we performed a targeted follow-up search in Swift/BAT rate data. Applying the followup to all of our triggers - including triggers below the detection threshold yielded 1736 temporally coincident events with association probability above $90\%$. The resulting probabilistically ranked catalog substantially expands the population of short GRBs and magnetar flares detected in GBM data and provides a statistically robust framework for multimessenger searches.

Gamma-ray bursts temporal profile can be extremely variable, going from a single pulse of a few seconds duration to multiple superimposed pulses occurring over tens or even hundreds of seconds. The variability displayed in the lightcurve of each gamma-ray burst can be the result of the activity taking place in the central engine that generates these violent phenomena, as well as due to magnetic reconnection activities at larger distances. The objective of this work is to find the shortest variability hidden in the lightcurves of the GRBs, with particular focus for the ones with measured redshift, on timescales as short as few milliseconds. This variability will then be related to physical characteristics of the central engine, and evidences of its relation with the spectral parameters of the burst, such as the isotropic energy and peak energy, will be presented. This research is even more relevant in view of the future generation of satellites with improved timing resolution, that will allow us to explore the possible variability in the microsecond region.

We present a novel possibility that a network of domain walls bounded by cosmic strings generates a stochastic gravitational wave background (SWGB) signal originating from the spontaneous breaking of a gauged $U(1)_F$ flavor symmetry and the subsequent breaking of discrete $Z_2$ symmetry that accommodates dark matter. The gravitational wave (GW) spectrum produced by the string-bounded-wall network can be detected for high $U(1)_F$ breaking scales in forthcoming GW detectors including LISA, ET and SKA. The GW signal exhibits a distinctive frequency slope, in the infrared, compared to the standard cosmic-string case, in the frequency range between micro-hertz and hertz. We develop a possible strategy to distinguish and characterize GW spectrum of the hybrid defect from from other defects, such as stable cosmic strings, via employing the exact calculation with a machine-learning surrogate, based on a multilayer perceptron (MLP), trained on spectra obtained from the full numerical treatment. This is then used for rapid inference in the detector-specific signal-to-noise ratio (SNR) computation which also makes the process fast and efficient. We also discuss some possible complementarity between GW searches and Flavor observables in the laboratory.

In this work, the effects of the cosmological constant on dark energy stars in Finch-Skea spacetime are systematically investigated within the framework of Einstein gravity. A static and anisotropic stellar configuration composed of ordinary matter and dark energy is constructed by employing the complexity factor formalism to obtain the temporal metric potential. The interior solution is smoothly matched to the exterior Schwarzschild-(anti-)de Sitter spacetime through appropriate boundary conditions. The influence of positive and negative cosmological constants on the structural and stability properties of the compact star candidate Vela X-1 is investigated in detail. The results show that positive values of the cosmological constant produce larger and less compact configurations, whereas negative values lead to denser and more compact stars with stronger gravitational effects. The energy conditions are satisfied throughout the stellar interior for all considered cases. However, sufficiently large values of the cosmological constant introduce deviations from hydrostatic equilibrium and affect the causal and dynamical stability behavior of the model. Overall, the results demonstrate that the cosmological constant plays an important role in determining the compactness, equilibrium and stability behavior of dark energy stars in Finch-Skea spacetime.

We put forward a quantum model of cosmology that is exactly periodic but avoids the Boltzmann Brain problem. If the universe is described by a quantum state evolving unitarily in a finite-dimensional Hilbert space, its evolution will be recurrent: given enough time, the state will return arbitrarily close to its initial state. There is a worry that such a scenario cannot be phenomenologically acceptable, because the state will spend most of its time in a high-entropy equilibrium macrostate, with rare fluctuations downward in entropy, and the vast majority of observers will be minimal fluctuations away from equilibrium, or ``Boltzmann Brains." Here we show that this is not necessarily true. If the differences in energy eigenvalues are commensurable, the evolution is not simple recurrent, but exactly periodic. Moreover, if the state starts at minimum thermodynamic entropy, its evolution can feature a distinguished entropy excursion that is much more pronounced than one would expect from the conventional expression $P(\Delta S) \propto \exp(-\Delta S)$. This excursion could represent our Big Bang, with relatively few Boltzmann fluctuations occurring in the subsequent equilibrium phase before a Big Crunch occurs and the cycle begins again. We speculate on the spacetime interpretation of this kind of quantum universe.

We show that axions cause extremal black holes to have singular horizons. This is true for almost all values of the axion mass and coupling provided the black hole is rotating and has some arbitrarily small nonzero charge. When the axion mass becomes large, these singularities are related to the recently discovered singularities induced by higher-derivative corrections to the Einstein-Maxwell equations. Away from extremality, this effect produces anomalously large tidal forces in the vicinity of near-extremal horizons, causing breakdown of the effective theory.

We investigate the effect of millicharged particles (MCPs) with electric charge $qe\ll e$ and mass $m_\chi$ on the late-stage evolution phases of low-mass stars in globular clusters. We predict the $R_2$ parameter -- the ratio of the number of stars in the asymptotic giant branch (AGB) phase to the number of stars in the horizontal branch (HB) phase -- and compare it against globular cluster data. While the production of MCPs shortens both the HB and AGB lifetimes, a larger reduction in the AGB phase arises from the higher temperatures in the helium-burning shell. We find the strongest bounds in the range $10\,\mathrm{keV}\lesssim m_\chi\lesssim 100\,\mathrm{keV}$, reaching charges as small as $q\simeq 5\times10^{-13}$ and surpassing existing constraints by up to two orders of magnitude.

A long-standing problem in the simulation of neutron star spacetimes is the treatment of vacuum regions outside the stars. The use of an artificial low-density atmosphere is a common robust approach within Eulerian hydrodynamics that, however, introduces baryon-mass violation even with conservative numerical schemes. We propose a simple numerical algorithm that ensures exact mass conservation by means of an appropriate local rescaling of the atmosphere. The scheme is combined with a low-order flux correction and it can be further augmented by a pseudo-vacuum treatment that enforces strict vacuum in the outer regions far from the central objects. We demonstrate the effectiveness of these vacuum treatments with binary neutron star mergers simulations spanning multiple orbits and the postmerger phase, and including a microphysical equation of state. The rescaling algorithm guarantees mass and electron number conservation to round-off precision. The pseudo-vacuum treatment shows slightly larger but approximately constant violations and can improve the computation of fast tail ejecta as well as provide convergent gravitational waves of quality comparable to the standard atmosphere. Overall, results from different atmosphere treatments and a two-code comparison suggest that current computations of gravitational waves and (dynamical) ejecta in the presence of an artifical atmosphere are robust, provided that conservative adaptive mesh refinement with flux correction is employed.

By varying the symmetry energy slope ($L$), I investigate how the exotic content within the interiors of neutron stars changes and how it affects both macroscopic and microscopic quantities. Using two different parametrizations (L3$\omega\rho$ and BigApple), and three different possibilities about the neutron star core (nucleons+hyperons, nucleons+deltas, nucleons+hyperons+deltas), I show that, for the models analyzed in this work, changing the slope barely changes the amount of hyperons, but it can strongly suppress the $\Delta$ resonances for large values of $L$. I also show that, in general, the presence of exotic content will be more evident for lower values of $L$ than for large ones. Differences and similarities between the two parametrizations are also analyzed.

We present a community-wide effort to develop a strategy and action plan to advance heliophysics and space weather modeling through open science. While open science has the potential to enhance the quality and pace of scientific discovery, its application to scientific modeling requires more careful consideration regarding open data and open software guidelines, as scientific models differ significantly from data analysis software. We gathered feedback from modeling teams worldwide through a living survey and discussion sessions at the 2024 Open Science Workshop in College Park, USA, and at the 2025 COSPAR ISWAT Working Meeting in Cape Canaveral, USA. We complement these findings with lessons learned from almost 25 years of experience at the Community Coordinated Modeling Center in enabling open use of models. We identify key roadblocks in current open science practices and guidelines and offer recommendations for future progress across four overlapping themes: open use of models and simulation results, open validation, open development, and open collaboration. An essential outcome of the discussion is the need for model developers and model users to speak with a united voice and promote the role of models in future open science efforts. We introduce a new cross-domain community initiative called the Heliophysics Open Modeling Environment (HOME), which will be integrated as an overarching activity within COSPAR ISWAT. HOME will serve as a platform for modelers and model users to work together, facilitate community modeling, improve the scientific return on modeling investment, and advance understanding, modeling, and forecasting in heliophysics and space weather.

The bulk motion of E-region radar aurora provides a sparsely distributed, direct measurement of the ionospheric electric field in intermittent bursts. We present a tracking procedure for \textsc{icebear} VHF measurements of Farley-Buneman waves. Each cluster is represented as an $\alpha$-shape; frame-to-frame association is a Hungarian linear-assignment problem with a cost combining centroid distance and shape Intersection-over-Union; kinematic prediction amounts to a degenerate Kalman filter. Births, deaths, splits, and mergers are monitored; each tracked trajectory is reduced to per-segment velocities by piecewise-linear regression. We validate against a Defense Meteorological Satellite Program (DMSP) conjunction on 20 May 2021 and Swarm ion-drift statistics. During the G5 storm of 10 May 2024, on closed dayside field lines, the method recovers a five-second cluster at $11{,}240\pm660$~m/s, implying $\approx 560$~mV/m -- exceeding documented sub-auroral thermal emission speeds and the most extreme reported sub-auroral drifts. The detection is consistent with extreme E-field structures appearing as short-lived bursts.

Neutrino rest mass enables left-handed states to "flip" to right-handed states and vice versa. In-medium effects can enhance the probability for such spin-flip. We demonstrate that a full many-body calculation of this process in neutrino-dense environments can lead to spin-flip probabilities that exceed by orders of magnitude those calculated with mean-field treatments. We study simple configurations with a few neutrinos in well-defined momentum states, for which we show that the helicity conversion enhancement is connected to many-body momentum exchange. Such an effect would therefore be missed in a calculation that considers only forward processes. We speculate on the potential astrophysical implications of these results and the range of applicability of our calculation and its limitations.

Orbital transfers in multi-body systems are often studied as isolated trajectory design problems, making it difficult to identify the larger transport structure connecting families of periodic orbits, including which families act as hubs, gateways, relays, or persistently difficult-to-access regions. This work introduces a reachable-set-based framework for constructing orbital networks in the circular restricted three-body problem. Finite-$\Delta V$ and finite-time-of-flight reachable-set overlaps are used to infer accessibility relationships between representative periodic orbit families on a common Jacobi energy manifold and to assemble these relationships into a weighted orbital network. Applied to the Earth-Moon system, the resulting network reveals distinct accessibility regimes in which direct reachability, graph connectedness, and feasible multileg closure emerge separately. The analysis identifies multi-orbiter cycler orbits as the dominant hub, gateway, and relay families, with the (3,2)-cycler dominating across much of the sampled budget plane and the short-period (1,1)-cycler dominating in the low-time-of-flight regime, while the stable 2:1 resonant orbit remains persistently difficult to access. Although the maximum-budget network is nearly complete in a binary sense, its weighted accessibility remains strongly non-uniform. Selected proxy-supported connections are refined into concrete trajectories through differential correction, with corrected transfer costs remaining below the proxy estimates in all tested cases. Together, the results demonstrate how reachable-set overlap geometry can expose large-scale transport structure in nonlinear gravitational systems without requiring exhaustive pairwise trajectory optimization.