研究動向

astro-ph.GA2026年8月25日

A simulation-based quality-control framework for the broad-line region radius-luminosity relation

Juri Wladimir Seib, Francisco Pozo Nuñez, Sarah Elena Ivana Bosman

The broad-line region (BLR) radius-luminosity (R-L) relation underpins single-epoch black hole mass estimates in active galactic nuclei (AGN). The published Hβsample is heterogeneous in observational quality, and it remains unclear how much of its scatter is intrinsic rather than caused by systematics in lag recovery. We quantify the contribution of unreliable lag recovery to the observed scatter of the HβR-L relation and provide tools for quality control. We compile a publicly available databas…

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astro-ph.GA2026年8月25日

The descendants of $z \gtrsim 10$ JWST galaxies in the COLIBRE simulations

Xu Zhao, Carlos S. Frenk, Andrew Pontzen, Kyle A. Oman, Evgenii Chaikin, Isabel Santos-Santos, Shengdong Lu, Joop Schaye et al.

Recent observations with JWST have revealed a population of UV-bright galaxies at $z\gtrsim 10$. This discovery naturally raises the question: what do such early galaxies evolve into by the present day? In this work, we address this descendant question using the new-generation COLIBRE cosmological hydrodynamical simulations to trace bright galaxies selected at $z=10$ and follow their descendants to the present day. Most of the high-redshift galaxies do not survive as distinct, self-bound objects…

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astro-ph.EPastro-ph.SR2026年8月25日

Preparing for the Early eVolution Explorer: The Impact of Flare Temperature on Ozone Column Depth in Earth-Like Atmospheres

Jaime S. Crouse, Nicholas F. Wogan, Ward S. Howard, Meredith A. MacGregor, Guadalupe Tovar Mendoza, Jacob Lustig-Yaeger, Evgenya L. Shkolnik

Atmospheric photochemical models incorporating the impacts of stellar flares often assume a $\sim$9,000 K spectrum at ultraviolet-optical wavelengths. Recent multiwavelength observations, however, reveal a more complex picture with temperature measurements spanning 4,000-40,000 K, although the occurrence rates for flares with different temperatures remain unknown. Here, we model the evolution of a Proterozoic Earth-like world with 0.01 bar of O$_2$ under repeated flaring to identify the impact o…

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astro-ph.IM2026年8月25日

BlueBird 6 is Fainter than Block 1 Satellites

Anthony Mallama, Richard E. Cole

The mean apparent magnitude for BlueBird 6, the first Block 2 satellite of the BlueBird constellation, is 3.85 +/- 0.10 while that for Block 1 spacecraft is 3.30 +/- 0.07. So, BlueBird 6 is 0.55 magnitudes fainter. Likewise, the means of apparent magnitudes adjusted to a uniform distance of 1,000 km are 4.32 +/- 0.08 and 3.77 +/- 0.06, respectively. This difference is also 0.55 magnitude. The dimming is unexpected because the Block 2 satellites are ~3.5 times as large as Block 1. BlueBird 6 is o…

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astro-ph.EP2026年8月25日

Dust trapping, collisional velocity and velocity dispersion in gravito-turbulent discs

Cristiano Longarini, Cathie J. Clarke, Richard A. Booth, Cat Leedham

High-resolution ALMA observations indicate that planet formation is already well underway in the earliest stages of disc evolution, when discs are typically massive enough to be regulated by gravitational instability (GI). In this regime, the interplay between dust dynamics and GI may enable rapid core formation, but the conditions under which this process operates remain poorly constrained. In this work, we use three-dimensional global SPH simulations to investigate the dynamics of dust particl…

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astro-ph.IMastro-ph.CO2026年8月25日

Strong Lensing Cosmology with Population-level Calibrated Neural Ratio Estimation

Sreevani Jarugula, Brian D. Nord, Aleksandra Ćiprijanović, Shubhendu Trivedi

Strong gravitational lensing contains key information about cosmic acceleration. Modern and next-generation galaxy imaging surveys are expected to provide high-quality data on $\mathcal{O}(10^5)$ galaxy-galaxy lensing systems. The plethora and complexity of the data are likely to present computational challenges for parameter inference methods for fitting high-dimensional likelihoods, which are often analytically intractable. Neural Ratio Estimation (NRE) efficiently computes individual likeliho…

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astro-ph.GAastro-ph.SR2026年8月25日

The ALMA EGO-10 Survey of Massive Protoclusters: Correlation of 1.3 mm Continuum Source Clustering with Evolutionary State

Michael C. Logue, Claudia J. Cyganowski, Crystal L. Brogan, Todd R. Hunter, Alessio Traficante, Allison P. M. Towner, Stella S. R. Offner

Massive stars characteristically form in clustered environments. Characterising young massive 'protoclusters' is therefore crucial to constraining the mechanism(s) of massive star formation, and of the assembly of stellar clusters. We present 1.3 mm continuum results from the ALMA EGO-10 imaging survey, targeting ten Spitzer GLIMPSE Extended Green Objects (EGOs) - massive protostars with active outflows traced by extended 4.5 $μ$m emission. Our sensitive 1'.6$\times$1'.6 mosaics reveal rich prot…

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astro-ph.HE2026年8月25日

Disentangling propagation effects from Fast Radio Burst spectra: An analysis on simulated data

Aishwarya Kumar, Fereshteh Rajabi, Martin Houde

We present a methodology to decouple propagation effects, specifically scattering and dispersion, from the intrinsic spectro-temporal properties of repeating Fast Radio Bursts. Utilizing the Triggered Relativistic Dynamical Model, and assuming superradiance as the emission mechanism, we generate simulated sub-bursts and inject controlled levels of scattering and residual dispersion. For each burst, we measure the sub-burst slope, defined as the trajectory of the centroids in the dynamic spectrum…

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astro-ph.SR2026年8月25日

Solar-Cycle Variation of Newly Emerging Coronal Holes during Solar Cycle 24

Akash Vinod Shirke, Khagendra Katuwal

Coronal holes (CHs) are regions of predominantly open magnetic field and important sources of high-speed solar wind streams. We present a manually compiled catalogue of newly emerging CHs during Solar Cycle 24 (2010-2019), identified from daily CHIMERA maps provided by SolarMonitor. Unlike existing area-based catalogues, our dataset tracks the daily emergence of new CHs in northern, southern, and equatorial latitude zones. The emergence rate of equatorial CHs is anti-correlated with the Internat…

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astro-ph.GAastro-ph.CO2026年8月25日

The Road to Normalcy: Environment-Driven Evolutionary Pathways for Primordial Black Holes

Saiyang Zhang, Junehyoung Jeon, Boyuan Liu, Volker Bromm, Priyamvada Natarajan

We investigate how cosmological environment regulates the evolution of primordial black hole (PBH) seeds in the early universe using a suite of hydrodynamical simulations. Unlike traditional seeding channels, PBHs provide early BH seeds without the need of special conditions for gas collapse/fragmentation that favor overdense regions, thus covering diverse large-scale environments. We find that PBHs follow distinct evolutionary pathways depending on the gas supply and halo assembly history. In u…

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math.PReess.SYphysics.space-ph2026年8月25日

Stochastic Dynamics of Low Earth Orbit Near Full Capacity

Priyank Behera, Aditya S. Gopalan, Harsha Honnappa

The capacity of Low Earth Orbit (LEO) to sustain space operations is under mounting pressure from megaconstellations, legacy fragmentation debris, and new payload classes. Existing assessments of orbital capacity and debris evolution are largely deterministic, tracking mean populations of intact satellites and fragments with ordinary differential equations; they cannot capture the inherent randomness of collisions, breakup sizes, and launch schedules. We develop a stochastic extension of the two…

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gr-qcastro-ph.COastro-ph.HE2026年8月25日

Updated Upper Limits on the Isotropic Gravitational-Wave Background from LIGO, Virgo, and KAGRA Data through April 2025

The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration, A. G. Abac, A. Abe, I. Abouelfettouh, F. Acernese, K. Ackley et al.

We report results from a search for an isotropic stochastic gravitational-wave background using data collected by the LIGO--Virgo--KAGRA Collaboration. The analysis uses data from the first observing run through April 1, 2025, during the fourth observing run. New frequency-domain cuts are implemented to address a class of non-stationary spectral noise features that were not effectively identified and mitigated by existing data-quality checks in past analyses. Consequently, previously analyzed da…

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astro-ph.EP2026年8月25日

CHIANTE I: Obliquity Measurements of Four High-Priority Ariel Targets in Binaries

Alex S. Polanski, Malena Rice, Catherine A. Clark, Rachael M. Roettenbacher, Lily L. Zhao, John M. Brewer, Momo Ellwarth, Emily A. Gilbert et al.

We present the first results from CHIANTE: a program using the EXtreme PREcision Spectrograph (EXPRES) at the Lowell Discovery Telescope to characterize potential targets of the Ariel mission, anticipated to launch in 2031. We report Rossiter-McLaughlin measurements of four Ariel tier 3 hot-Jupiters which reside in binary star systems: KELT-2 Ab, KELT-3 Ab, TOI-1333 Ab, and TOI-1789 Ab. Joint modeling of EXPRES and archival radial velocities with photometry from TESS finds all four planets to be…

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astro-ph.GA2026年8月25日

Fragmentation and tidal locking in young quadruple systems

Xunchuan Liu

Young quadruple systems provide a particularly simple setting in which the connection between successive levels of fragmentation can be studied. Motivated by the recurring symmetric configurations observed in a small number of young systems, we propose a theoretical framework in which such configurations arise naturally during rapid collapse. Rotational fragmentation followed by secondary fragmentation can produce two comparable-mass components of a wide pair, each of which further fragments int…

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astro-ph.SR2026年8月25日

BLG723.31.34651 as an eclipsing Roche lobe-filling sdOB+WD binary

Alekzander Kosakowski, Charles E. Derbyshire, Sydney Jetton, Brad N. Barlow

We present a detailed observational analysis of BLG723.31.34651, the fourth reported eclipsing member of the class of Roche lobe-filling hot subdwarfs, using time series spectroscopy and multi-band photometric observations from the Goodman High Throughput Spectrograph on the 4.1-m SOAR telescope. Our light curves show periodic photometric variability at $P=64~{\rm min}$ from the tidally-deformed hot subdwarf donor and deep eclipses of the donor by an opaque accretion disc. We report two light cu…

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cs.LGastro-ph.IMstat.ML2026年8月25日

Traceable Spectral Inference via Influence Functions: Efficient Data Attribution and Error Proxies for the Ariel Mission

Nikki Grens, Luís F. Simões, Kai Hou Yip, Theresa Lueftinger

Interpretability is critical for machine learning models deployed in scientific space missions such as ESA's Ariel, where ground truth is unavailable during operations and physical plausibility must be assessed. While most explainable AI methods focus on feature attribution, this work investigates training data attribution through influence functions and introduces three key contributions for operational spectroscopy pipelines. First, influence is reformulated in terms of prediction rather than…

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astro-ph.IM2026年8月25日

Inverting and Up-channelizing Critically-Sampled Polyphase Filter Banks

Stephen Fay, Mohan Agrawal, Hsin Cynthia Chiang, Aman Chokshi, Jonathan Sievers, Simon Tartakovsky

Polyphase filter banks (PFBs) are widely used to channelize digitized time-domain data in real time. However, applications such as radio astronomy often require higher spectral resolution than real-time systems can provide. We introduce a circulant inverse-PFB formalism and present a new, scalable, fast Fourier transform (FFT)-based algorithm for inverting critically sampled PFBs. This formalism explicitly identifies the origin of quantization noise amplification and enables two complementary mi…

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astro-ph.EPastro-ph.IMcs.LG2026年8月25日

Exploring Long-period Architectures: Four New Planet Candidates from Kepler with Periods >342 days

Matthew T. Hansen, Jason A. Dittmann

The Kepler detection pipeline, as well as the transit method, has a bias towards shorter periods, leaving a dearth of detections at longer orbital periods. This relative lack of detections has left an incomplete picture of the architectures of exoplanet systems within the long-period regime. We have built a single transit detection pipeline, utilizing a classification convolutional neural network and the onboard spacecraft diagnostics of the Kepler spacecraft, to detect long-period planets. We a…

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astro-ph.GA2026年8月25日

FASHI DR2: A Catalog of 132 Low-Redshift HI 21 cm Absorption Systems

Chuan-Peng Zhang, Ming Zhu, Peng Jiang, Hong Guo, Yizhou Gu, Cheng Cheng, Jin-Long Xu, Nai-Ping Yu et al.

We present an untargeted survey of 21 cm HI absorption systems based on the second data release of the FAST All Sky HI survey (FASHI DR2), covering approximately 19,500 deg$^{2}$ at $z\lesssim0.09$. A total of 132 HI absorbers are identified, including approximately 60 new discoveries, forming one of the largest homogeneous samples of low-redshift HI absorbers assembled to date. The sample extends to continuum flux densities as low as 2.6 mJy, substantially below the limits of previous flux-limi…

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astro-ph.GA2026年8月25日

FASHI DR2: A Catalog of 132 Low-Redshift HI 21 cm Absorption Systems

Chuan-Peng Zhang, Ming Zhu, Peng Jiang, Hong Guo, Yizhou Gu, Cheng Cheng, Jin-Long Xu, Nai-Ping Yu et al.

We present an untargeted survey of 21 cm HI absorption systems based on the second data release of the FAST All Sky HI survey (FASHI DR2), covering approximately 19,500 deg$^{2}$ at $z\lesssim0.09$. A total of 132 HI absorbers are identified, including approximately 60 new discoveries, forming one of the largest homogeneous samples of low-redshift HI absorbers assembled to date. The sample extends to continuum flux densities as low as 2.6 mJy, substantially below the limits of previous flux-limi…

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astro-ph.SRphysics.space-ph2026年8月25日

Breakout/Interchange Reconnection as a driver of Jets, Fast CME, and Solar Energetic Particles

Pankaj Kumar, Judith T. Karpen, David Lario, Benjamin J. Lynch, Peter F. Wyper, Spiro K. Antiochos, P. K. Manoharan

Understanding how energetic particles are accelerated and released from the low corona into the interplanetary medium during solar eruptions is crucial for space weather research. Here, we present multiwavelength observations of a solar eruption that are consistent with breakout reconnection playing an important role in driving a fast coronal mass ejection (CME) and the associated solar energetic particle (SEP) event. Extreme-ultraviolet and radio observations reveal evidence of breakout reconne…

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astro-ph.SR2026年8月25日

Preparing for the Early eVolution Explorer: Photometric Diagnostics of Magnetospheric Accretion Geometry in Young Stellar Objects

Laura Venuti, Connor E. Robinson, Ann Marie Cody, Eric Gaidos, Meredith A. MacGregor, Neal J. Turner, Mark R. Swain, George Zhou et al.

The inner disk truncation radius, $R_T$, plays a crucial role in the regulation of star-disk interaction and the early evolution of star-disk-planet systems; however, measuring this parameter is observationally challenging. We present a new method for determining $R_T$ in young accreting systems that hinges on the color dependence of the accretion shock emission in multi-band time-domain surveys. Based on the accretion simulations of Robinson et al. (2017, 2021), we produce synthetic color-magni…

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astro-ph.HEgr-qc2026年8月24日

Binary Neutron Star Merger Simulations with Microphysical Equation of State using Spritz

Fatemeh Hossein Nouri, Jay V. Kalinani, Bruno Giacomazzo, Riccardo Ciolfi, Albino Perego

We present the first binary neutron star merger simulations performed with the general-relativistic magnetohydrodynamics (GRMHD) Spritz code employing a finite-temperature tabulated equation of state. Two magnetized binaries with the LS220 equation of state and a GW170817-like chirp mass, differing only in their mass ratios ($q=1$ and $q=0.7$), are evolved from the late inspiral through merger, hypermassive neutron-star (HMNS) formation, and delayed collapse to a black hole (BH). We investigate…

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astro-ph.EP2026年8月24日

Intra-system Uniformity through Planetary Embryo Accumulation

Donald Liveoak, Fred C. Adams

Intra-system uniformity is a key trend in observed exoplanet systems. Understanding the physical mechanisms which sculpt planetary systems into uniform or non-uniform configurations will help constrain theories of planet formation. Motivated by previous work showing that intra-system uniformity is a natural consequence of proto-planetary systems dissipating energy and settling into lower energy configurations, this paper explores the energy minimization hypothesis using $N$-body simulations. We…

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astro-ph.IMastro-ph.HE2026年8月24日

AI-Assisted Extraction of Follow-up Observations from GCN Circulars in Astro-COLIBRI

Fabian Schüssler, S. Bisero, M. Cellier, A. Ciric, B. Cornejo, I. Jaroschewski, A. Kaan Alkan, W. Kiendrébéogo et al.

We present a new Astro-COLIBRI component that converts free-text GCN Circulars into structured, event-linked follow-up records and combines them with structured reports submitted directly by the community. A continuously running Circular listener associates new reports with transient events, applies deterministic pre-analysis, and invokes a schema-constrained large language model extraction step for photometry, contacts, redshifts, and other reported results and metadata. The resulting records a…

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gr-qcastro-ph.HEhep-ph2026年8月24日

Complex frequency evolution of direct waves from binary black hole mergers

Ling Sun, Sizheng Ma, Patrick P. Chen, Andrew Laeuger, Neil Lu, Yanbei Chen

While no signal originating at a black hole's event horizon can reach future null infinity, information about the horizon and its immediate vicinity can be encoded in asymptotic properties of waves emitted by matter or field perturbations falling toward a growing/forming horizon. Within a response-filtered framework, "direct wave" denotes source-sensitive plunge and remnant-formation information revealed by filtering the black-hole response. Unlike a stationary damped sinusoid with a fixed compl…

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astro-ph.EPastro-ph.SR2026年8月24日

Potential sublimating exocomets around the young star PDS 70

Aline Novais, H. Jens Hoeijmakers, Alexandra Stockwell Murphy, Bibiana Prinoth, Anders Johansen, Klaudia Jaworska, Luan Ghezzi

Recent observations by the James Webb Space Telescope (JWST) have indicated the presence of water in the inner regions of the disc around the young protostar PDS 70, but the origin of this water remains unclear. Here we report the discovery of variable absorption lines of neutral sodium in archival High Accuracy Radial velocity Planet Searcher (HARPS) spectra of PDS 70. These lines vary strongly and stochastically on a daily basis, in amplitude, number, and radial velocity. Our measurements indi…

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astro-ph.GA2026年8月24日

An improved view of cosmic-ray transport and the galactic outflow in NGC 253

Shengtao Wang, George Heald, Stefan W. Duchesne, Xiaohui Sun, Guangxing Li, Jiangtao Li, Chao-Wei Tsai, Andrew J. Battisti et al.

The nearly edge-on starburst galaxy NGC 253 exhibits extended multiwavelength halo emission, making it an ideal laboratory for studying disk-halo transport. We present improved ASKAP 943 MHz and MWA 216 MHz total-intensity images with resolutions of 13 and 45 arcsec and rms noise levels of 16 $μ$Jy beam$^{-1}$ and 1 mJy beam$^{-1}$, respectively. After subtracting the thermal emission, we fitted the vertical synchrotron emission intensity and spectral-index profiles with one-dimensional advectio…

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astro-ph.COastro-ph.GAhep-ph2026年8月24日

Dynamics of Wave Structures in Multifield Fuzzy Dark Matter Halos

Yu-Ming Yang, Xiao-Jun Bi, Peng-Fei Yin

As a natural extension of the single-field fuzzy dark matter (FDM) model, multifield FDM has attracted increasing attention in recent years. This scenario is motivated both by the axiverse scenario predicted by string theory and by the possibility that multifield FDM may provide a better match to astrophysical observations than its single-field counterpart. In this work, we perform high-resolution numerical simulations to systematically investigate the dynamics of wave structures in multifield F…

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astro-ph.SRastro-ph.EPastro-ph.IM2026年8月24日

Solar chemical composition

A. M. Amarsi, N. Grevesse

The Sun is one of the fundamental benchmarks in astronomy, and there is ever growing interest in precise and accurate determinations of its chemical composition. We present the current state-of-the-art in spectroscopic determinations of the solar elemental abundances, that now routinely employ three-dimensional (3D) radiative-hydrodynamic simulations of the solar photosphere and post-processing in non-local thermodynamic equilibrium (non-LTE). We critically review the recent literature and prese…

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