研究動向

astro-ph.GA2026年7月18日

Euclid: Calibrating distances from surface brightness fluctuations with Early Release Observations of the Fornax cluster

R. Habas, M. Cantiello, G. Riccio, G. Raimondo, N. Hazra, S. Mei, A. Lançon, G. D'Ago et al.

Surface brightness fluctuations (SBF), the pixel-to-pixel variations in flux that arise from the statistical distribution of stars in galaxy images, provide a powerful tool to measure redshift-independent distances from photometric data alone. This method is particularly important in the era of large imaging surveys, such as those carried out during the Euclid mission. Here we present the first application of SBF to Euclid data, using the FAST-SBF code to measure stellar fluctuation amplitudes i…

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astro-ph.SR2026年7月18日

SEP-PRISM Data: A multi-source dataset for solar energetic particle forecasting

Yian Yu, Yang Chen, Lulu Zhao, Kathryn Whitman, Ward Manchester, Tamas Gombosi

Solar energetic particle (SEP) event forecasting often involves integrating heterogeneous observations that differ in cadence, temporal coverage, format, and historical availability, posing challenges for reproducible analysis of data-driven approaches. This paper presents SEP-PRISM Data, a curated multi-source dataset designed for 24-hour ahead forecasting of operational SEP events, defined by proton flux exceeding 10 pfu in the GOES > 10 MeV channel. SEP-PRISM Data integrates flare records, ac…

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astro-ph.HE2026年7月18日

X-ray polarization of Z-type neutron star low-mass X-ray binaries -- II. Spectropolarimetric analysis

Andrea Gnarini, Francesco Ursini, Giorgio Matt, Stefano Bianchi, Fiamma Capitanio, Massimo Cocchi, Sergio Fabiani, Ruben Farinelli et al.

IXPE has provided for the first time detailed energy- and time-resolved X-ray polarimetry of Z-type neutron star low-mass X-ray binaries (NS-LMXBs) as they move along their color-color diagrams (CCDs). These sources can reach the highest polarization observed for NS-LXMBs in the 2-8 keV range when they move along the horizontal branch. In a previous paper, we characterized the spectral state of a sample of Z-sources using the CCD and estimated the polarization with model-independent analysis. He…

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astro-ph.HE2026年7月18日

Eccentricity as a Magnifying Glass: Precision Population Inference Enabled by Eccentric Neutron Star-Black Hole Mergers

Alberto Salvarese, Hsin-Yu Chen, Aaron Zimmerman, Snehal Tibrewal

The formation history of compact binary systems remains one of the key open questions in astrophysics. Theoretical studies generally favor isolated binary evolution for neutron star-black hole (NSBH) systems, which tends to produce nearly circular orbits. However, recent analyses of the gravitational-wave event GW200105 indicate that its source has measurable eccentricity, suggesting that alternative formation channels may also contribute. It has been shown that the intrinsic parameters of eccen…

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astro-ph.HE2026年7月18日

Impact of eccentricity and higher-modes on neutron star-black hole parameter estimation

Snehal Tibrewal, Aasim Jan, Aaron Zimmerman, Hsin-Yu Chen

Detections of gravitational waves from neutron star-black hole systems provide avenues for studying extreme matter, constraining binary formation channels, and testing the nature of compact objects in strong gravity. Eccentric signatures in the signal further enhance this potential by improving parameter estimation and offering clues about binary formation. Because eccentricity is primarily imprinted during the inspiral phase, it is often weakly constrained or missed entirely in binary black hol…

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astro-ph.HE2026年7月18日

Discovery of $γ$-Ray Pulsations from the Extreme-Spin-Down Millisecond Pulsar PSR J0435+3233

Mengqing Zhang, Shengbin Pei, Pengfei Zhang

Motivated by the recent discovery of PSR~J0435+3233, a millisecond pulsar with an exceptionally large period derivative of $\dot{P}=4.9\times10^{-17}\ {\rm s\,s^{-1}}$ and a high spin-down luminosity of $\dot{E}=5.89\times10^{37}\ {\rm erg\,s^{-1}}$, we analyze $\sim$17~yr of observations obtained with the \textit{Fermi} Large Area Telescope for the pulsar. We identify the cataloged source 4FGL~J0435.5+3232, located only $0.01^{\circ}$ from the radio timing position, as the $γ$-ray counterpart o…

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astro-ph.IM2026年7月18日

Commissioning and on-sky performance of FiberPol: a fiber-fed spectropolarimetric system for the SAAO 1.9 m telescope

Siddharth Maharana, K. C. J. Dennison-Farrar, Sabyasachi Chattopadhyay, Nikita Rawat, Nidhi Mehandiratta, J. C. Viljoen, Matthew Bershady, David Buckley et al.

At the South African Astronomical Observatory (SAAO), we have developed FiberPol$-$ a spectropolarimetric front-end for the SpUpNIC spectrograph on the 1.9 m telescope fed by fibers. In conjunction with SpUpNIC, it combines two niche techniques: fiber-spectroscopy and polarimetry to enable a wide range of science cases, particularly for studies of the interstellar medium, and serves as a technology pathfinder for implementing polarimetry larger facilities such as the 10 m Southern African Large…

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astro-ph.GA2026年7月18日

Dynamics and geometry of the inner sub-parsec-scale jet in 3C 279 observed with the Event Horizon Telescope

Hendrik Mueller, Sebastiano D. von Fellenberg, Ai-Ling Zeng, Paul Tiede, Thomas P. Krichbaum, Roman Gold, Tuomas Savolainen, Jae-Young Kim et al.

The 2021 Event Horizon Telescope observations resolve the innermost jet region of the blazar 3C279 with unprecedented detail. The reconstructed images consistently reveal a compact core elongated nearly orthogonal to the large-scale jet axis. This rarely observed morphology recurs across multiple epochs and from 22-230 GHz and is therefore intrinsic rather than an imaging artifact. Geometric model fitting identifies several components with apparent speeds up to 10c, requiring bulk Lorentz factor…

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physics.flu-dynastro-ph.GAastro-ph.SR2026年7月18日

From Triadic Interactions to Kolmogorov Scaling: A Deterministic, Scale-Resolved Formulation of Energy Flux

Erik Bertram

We develop a deterministic, scale-resolved formulation of energy transfer in the three-dimensional incompressible Navier-Stokes equations based on an explicit triadic decomposition of the nonlinear term in Fourier space. Using a systematic dyadic localization of the velocity field, we derive an exact representation of the nonlinear energy flux across scales and organize it in terms of interactions between well-defined scale components. Under suitable smoothness assumptions, we obtain an absolute…

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astro-ph.IMastro-ph.CO2026年7月18日

OpenCosmo: Community Portal and Analysis Framework for Flagship Cosmological Simulations

Patrick R. Wells, Michael Buelhmann, Patricia Larsen, William M. Hicks, Manpreet Dhillon, Idunnuoluwa A. Adeniji, Katrin Heitmann, Salman Habib et al.

Cosmology is a precision observational science, and large simulations are necessary components of many analyses. These simulations are computationally expensive and produce massive, complex datasets; sharing them widely -- to enable further explorations, comparison with observations, and communication with general audiences -- is crucial to realizing their scientific value. In this paper, we introduce the OpenCosmo project, which provides flexible access to, and analysis of, flagship cosmologica…

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astro-ph.GA2026年7月17日

Infrared spectroscopy of gas-phase hydrogenated and methylated pyrenes: from laboratory spectra to the simulated 3.4 $μ$m emission band

Karine Demyk, Christine Joblin, Louan de Bentzmann, Dominique Toublanc, Giacomo Mulas

Observations of the aromatic infrared emission band at 3.3 $μ$m often reveal satellite emission features in the 3.4 - 3.6 $μ$m range. While the 3.3 $μ$m band is attributed to the CH stretching vibration of polycylic aromatic hydrocarbons (PAHs), the satellite bands - particularly its prominent 3.4 $μ$m component - is assigned to aliphatic CH stretching vibrations in hydrogenated and methylated PAH-like species. Our aim is to derive state-of-the-art infrared emission spectra for aliphatic-contain…

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astro-ph.IM2026年7月17日

Coherence differential imaging using gradient-boosted decision trees for the direct detection of exoplanets

Johan Mazoyer, María J. Mellado-Tenorio, Axel Potier, Christian Wilkinson, Lukas Delaye, Raphaël Galicher, Iva Laginja

Coronagraphic imaging of exoplanets is limited by residual speckles that mimic planets. Advanced post-processing is essential for current and future instruments on the ground or in space. Current techniques are time-intensive and limited. ADI requires long sequences and is limited at small separations. RDI is also time-consuming and sensitive to speckle evolution, leading to imperfect subtraction. Coherence Differential Imaging (CDI), which we successfully demonstrated on SPHERE, offers a faster…

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astro-ph.GAastro-ph.HE2026年7月17日

Radio-detected Lya emitters at 1.88 < z < 3.52: AGN fraction and Lya emission

Sai Zhai, Huub Röttgering, Anniek J. Gloudemans, Erin Mentuch Cooper, Maya H. Debski, Gregory Zeimann, Matt J. Jarvis, Leah K. Morabito et al.

Lya emitters (LAEs) are galaxies with strong Lya emission, tracing early star formation and ionizing radiation. Their connection to active galactic nuclei (AGNs) is key to understanding the mechanisms behind (extended) Lya emission. In this work, we measure the fraction of LAEs identified as radio-emitting AGN (fAGN,radio) and the fraction of radio sources that exhibit Lya emission (fLya) to investigate the connection between radio AGN activity and Lya emission at 1.88 < z < 3.52. We identify 92…

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astro-ph.HEastro-ph.SRhep-ph2026年7月17日

Non-thermal emission from the vicinity of the magnetar CXOU J171405.7-381031

Manoel F. Sousa, Rita. C. Anjos

Magnetars are neutron stars with ultra-strong magnetic fields ($B \sim 10^{14}$-$10^{15}$ G) and are promising candidates for high-energy particle acceleration. We present a multiwavelength analysis of the region surrounding CXOU J171405.7-381031, a magnetar associated with the supernova remnant (SNR) CTB 37B. The broadband spectral energy distribution spanning radio to TeV energies is modeled using leptonic and lepto-hadronic scenarios, with particle populations constrained using Markov Chain M…

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astro-ph.EP2026年7月17日

Spectral features in the visible spectra of the Enceladus particle plume and E ring: Potential evidence of organic materials and/or missing sub-micron particles

M. M. Hedman, S. M. MacKenzie

Visible spectra of the Enceladus particle plume and E ring contain evidence for a change in spectral slope around 0.5 micron. This feature can be seen in data obtained by both the Visual and Infrared Mapping Spectrometer (VIMS) and Imaging Science Subsystem (ISS) onboard the Cassini Spacecraft, and is consistent with the slope change seen in the surface spectra of Saturn's rings and moons that has been attributed to either organics or iron compounds. The observed spectral features in the plume a…

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astro-ph.EPastro-ph.GAastro-ph.SR2026年7月17日

Extending dynamical mass measurements: probing GI as a possible origin of mm-dust spirals

V. Pezzotta, S. Facchini, A. F. Izquierdo, G. Lodato, C. Longarini, J. Bae, M. Galloway-Sprietsma, C. Pinte et al.

Constraining the total mass of protoplanetary disks is crucial to determine the availability of material for planet formation. Yet, providing accurate and precise measurements of the disk mass is challenging. Investigating the gas dynamics is a powerful, tracer-independent method to precisely characterize disk masses. By fitting the velocity rotation curves of different molecular tracers with an accurate model including the disk thermal stratification and self-gravity, we constrain the stellar m…

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physics.plasm-phastro-ph.HE2026年7月17日

Relativistic Scaling and Magnetization-Current Feedback in Stern Gerlach-Modified Pair-Plasma Reconnection: SpinPIC2D Validation and Nonlinear Regimes

K. Nykyri

We investigate the relativistic scaling and electromagnetic feedback of Stern--Gerlach (SG) force driven spin transport in pair-plasma reconnection with SpinPIC2D. The model advances relativistic proper momentum and magnetic BMT spin precession, applies the SG force, deposits spin magnetization, and includes $\mathbf J_M=\nabla\times\mathbf M$ in Ampere's law. In a weak-seed scan at fixed $γ_{\rm tr}=2$, the normalized global magnetic flux-growth remains near the classical control-run for $Ξ\le0…

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astro-ph.GA2026年7月17日

The S-PLUS Fifth Data-Release: Over 4500 square degrees of the Southern Sky and a multicolor view of the Hydra and Antlia galaxy clusters

Erik Vinicius Rodrigues de Lima, Gustavo Bernhard Oliveira Schwarz, Fábio Rafael Herpich, Felipe Almeida-Fernandes, Lilianne Nakazono, Eduardo Alberto Duarte Lacerda, André Santos, André Luiz Figueiredo et al.

We present the 5th data release (DR5) of the Southern Photometric Local Universe Survey (S-PLUS), covering 4592 square degrees across 2491 fields. Observations were conducted with the T80-South, a Brazilian robotic telescope equipped with the Javalambre 12-filter system, containing five broad- and seven narrowband filters. Data products feature FITS images and extensive catalogs containing fluxes, magnitudes, and shape parameters for over 113 million detections. In addition, several value-added…

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astro-ph.IMastro-ph.GA2026年7月17日

Compressing radio interferometric visibility data into a probabilistic model using sparse Gaussian processes

Takafumi Tsukui

Next-generation radio interferometers will produce massive data volumes, making it impractical to store original visibility measurements and later combine observations in $uv$ spatial frequency space. Visibility measurements at similar $uv$ locations measure the same signal but different noise realizations. In principle, these measurements can therefore be compressed by storing only the inferred mean visibility and its uncertainty. We propose modeling the visibility with a sparse Gaussian proces…

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astro-ph.SR2026年7月17日

Solar Cycle Variation of the Distribution of Photospheric Magnetic Flux Features

Callan N. Noble, Clare E. Parnell, Thomas Neukirch

We use statistical tools to analyse data from the Solar Dynamics Observatory Helioseismic and Magnetic Imager to determine the distribution of the magnetic flux of photospheric magnetic features and its variation over a full solar cycle. In particular, we use statistical figures of merit to test how well different types of probability density function represent the magnetic flux distribution inferred from the data and how their shape changes over the solar cycle. Our analysis shows that a double…

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astro-ph.GA2026年7月17日

Chemical Evolution of Galaxies: Past, Present and Future

Francesca Matteucci

In this paper I will describe the basic principles of chemical evolution of galaxies, its main ingredients and uncertainties. By means of chemical evolution we can perform the so-called galactic archaeology, which consists in reconstructing the history of star formation of galaxies and in particular of the Milky Way, starting from the observed stellar and gas abundances. Galactic archaeology is a powerful tool to predict also the behaviour of galaxies at high redshift. In particular, we adopt th…

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astro-ph.HE2026年7月17日

A cosmic-ray loaded nascent outflow driven by a massive star cluster

Marianne Lemoine-Goumard, Lucia Härer, Lars Mohrmann, Romain Bernet, Jim Hinton, Giada Peron, Brian Reville, Luigi Tibaldo et al.

Cosmic rays are widely held to drive outflows from star-forming galaxies and profoundly influence galaxy evolution. Direct evidence for cosmic-ray carrying outflows is however lacking. At the same time there is increasing awareness of the importance of massive star clusters in the acceleration of cosmic rays in galaxies. Here we report on the discovery of a nascent outflow driven by the massive star cluster Westerlund 1. Giga-electronvolt gamma-ray emission coincident with a cavity visible in at…

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astro-ph.IMastro-ph.SR2026年7月17日

Radial velocity and atmospheric parameter calculations for the GaiaNIR spectrograph

Szabolcs Mészáros, David Hobbs, Anna Liptrott, David Katz, Ricardo Schiavon, Viktória Pap, Anthony G. A. Brown, George Seabroke et al.

Context. The upcoming GaiaNIR mission is currently planning to add a near-infrared spectrograph to its payload in order to enhance its scientific return, particularly for mapping the dust-obscured regions of the Milky Way. Aims. This study aims to identify the optimal wavelength region between 800 and 2300 nm for the proposed GaiaNIR spectrograph to maximize the precision of radial velocities and atmospheric parameters. Methods. To find its spectral range, we generated 10000 synthetic spectra fr…

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astro-ph.EPastro-ph.IM2026年7月17日

Accuracy Analysis of VLBI Universal Time Measurement Based on a GNSS Single-Station Regional Ionospheric Model

Xu-chong Duan, Dang Yao, Yuan-wei Wu, Zhe Zhang, Jia Liu, Xu-hai Yang

Universal Time (UT1) is a key parameter characterizing Earth's rotation, and very long baseline interferometry (VLBI) is the mainstream technique for measuring UT1. To address the limitations in the timeliness and accuracy of existing global ionospheric models for single-frequency VLBI UT1 measurements, we construct a single-station regional ionospheric model using GNSS data from the VLBI stations on the Jilin-Kashi baseline. We apply this model to VLBI observations and compare its correction pe…

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astro-ph.SR2026年7月17日

Three-dimensional evolution of a solar filament with multipoint observations

Qingmin Zhang, Jun Dai, Beili Ying, Ye Qiu, Li Feng, Chuan Li, Hongqiang Song, Yue Zhou et al.

In this paper, we first devise a geometrical model, featuring a torus-like flux rope based on the shape of 3DCORE model. The global shape of the torus is an ellipse, while the cross sections are circular along the torus. The thinnest point is located between the Sun center and photosphere. Deflections and inclination are considered as well. Using multiwavelength observations from perspectives of Earth, Ahead-STEREO (STA), and Solar Orbiter, we apply the model to three-dimensional (3D) reconstruc…

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astro-ph.GA2026年7月17日

Testing various assumptions for radiolysis, non-diffusive chemistry, and chemical desorption in cold cores

V. Wakelam, T. Tu

To study interstellar gas and grain chemistry, gas-phase astrochemical models have been developed since the early 1980s and gas-grain models since the 1990s. Each published model includes various assumptions mainly for surface processes. In this paper, we compare recently added mechanisms for grain surface chemistry, namely, non-diffusive chemistry, radiolysis, and chemical desorption. Several formalisms for these processes have been added to our astrochemical model Nautilus, and we tested them,…

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astro-ph.HE2026年7月17日

Stable X-ray reverberation lags in the black hole X-ray binary Swift J1727.8-1613

Wei Yu, Sinan Allak, Zi-Xu Yang, Xiao Fan, Andrea Santangelo, Tian-hao Xie

Aims. We investigate the evolution of X-ray reverberation lags in the black hole X-ray binary Swift J1727.8-1613 during its 2023 outburst, with the aim of probing the inner accretion flow geometry across spectral states. Methods. We analyzed NICER observations covering the low-hard state (LHS) and hard-intermediate state (HIMS). The time lags were computed using Fourier-based techniques, and we constructed lag-frequency and lag-energy spectra. To obtain a robust estimate of the soft lag amplitud…

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astro-ph.SR2026年7月17日

Explainable AI for Solar Flare Prediction: Quantitative Magnetic Field Analysis of Model-Focused Regions

Z. Zheng, Q. Hao, C. Li, P. F. Chen, J. R. Hu, M. D. Ding, C. Fang

Solar flares are intense energy release events in the solar atmosphere that may pose significant space weather hazards, which makes developing reliable prediction models essential. Although deep learning methods, particularly convolutional neural networks (CNNs), demonstrate strong predictive performance when using solar magnetograms, their scientific credibility is undermined by a lack of physical interpretability. Explainable artificial intelligence (XAI) offers a potential solution. However,…

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astro-ph.EP2026年7月17日

Debris Evolution from Spacecraft Fragmentation in Earth-Moon Distant Retrograde Orbits

Yuyan Wu, Peng Shu, Yuqiang Li

With the rapid surge in lunar exploration and the planned expansion of cislunar infrastructure, cislunar space has become a strategic focal point for global aerospace activities. This proliferation of spacecraft heightens the risk of fragmentation events, such as unintended explosions or orbital collisions which serve as the primary source of hazardous orbital debris. Given the potential threat these fragments pose to mission safety and long-term orbital sustainability, it is imperative to inves…

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astro-ph.IM2026年7月17日

Torsional-X Seismometer for Lunar Decihertz Gravitational-Wave Detection

Yulin Xia, Denis Martynov, Huan Yang, Haixing Miao

The lunar gravitational-wave antenna concept uses the Moon as a resonant detector instrumented with precision seismometers, targeting the decihertz band between ground- and space-based observatories. We propose a compact monolithic fused-silica torsional-X seismometer that re-engineers garden-gate acceleration-to-rotation transduction for this regime through a high-tension dual-fiber suspension. Its designed millihertz-scale resonance and ultra-low mechanical dissipation enable a nearly order-of…

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