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HIGH-ENERGY TRANSIENTS · DAILY LITERATURE REVIEW
2026 年 7 月 17 日 星期五 · 数据截至 arXiv / ADS 最新收录日
I.

今日头条

No Breaking · 无突发
今日无通过复核的重大进展

当日 10 篇核心与相关文献均为常规推进,核心 6 篇已按优先级列于下方。

II.

核心文献

6 篇
01
优先级 95 · 引力波电磁对应体 · 多信使触发与联合 · BNS并合

High-Density Sound Speed and Post-Merger Dynamics

高密度声速与并合后动力学

J. Stroud (Institute for Nuclear Theory, University of Washington), D. Radice (Institute for Gravitation and The Cosmos, The Pennsylvania State University), S. Reddy (Institute for Nuclear Theory, University of Washington)

原文摘要Abstract

The density dependence of the speed of sound in cold neutron star matter remains poorly constrained and is central to determining the high-density equation of state (EOS). While binary neutron star (BNS) merger simulations increasingly incorporate detailed microphysics, the direct impact of the sound-speed in the neutron star core on observable signatures has not been systematically explored. We address this by introducing a simplified parametrization that suppresses microphysics while allowing controlled variation of the sound speed at supranuclear densities through its derivative with respect to the baryon chemical potential. Using the WhiskyTHC code, we perform a suite of fully relativistic BNS merger simulations and identify correlations between the sound-speed slope parameter and key merger outcomes, including remnant properties and post-merger GW frequencies. These results demonstrate that multimessenger observables are sensitive to the behavior of matter at the highest densities reached in neutron star cores. We further analyze gravitational-wave signals from the CoRe database of binary neutron star merger simulations employing more realistic equations of state. Our analysis reveals approximately EOS-independent relations between the derivative of the sound speed and the peak post-merger gravitational-wave frequency. Although these relations cannot be considered truly quasi-universal, they nonetheless indicate that post-merger gravitational waves retain measurable information about the EOS at he highest densities. At the same time, the remaining EOS dependence highlights the difficulty of isolating the underlying high-density physics and motivates the development of targeted parameterized frameworks for interpreting future multimessenger observations.

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亮点

创新性地用参数化声速模型隔离高密度物态效应,系统研究了其对并合后多信使信号的影响;发现并合后峰值频率与音速积分量间的准通用关系,为提取最高密度物态信息提供新途径。

脉络与展望

过去研究多基于潮汐形变等宏观量建立准通用关系,但这些量主要敏感于核饱和密度附近的物态Bauswein+ 2012。近期IPAD-TOV框架通过定义本征变量X和Ψ,构造了能直接编码高密度声速积分信息的参数D̃Cai+ 2025。本文以此为基础,引入可控声速斜率的简化模型,通过全相对论模拟揭示了f_pk与声速微分参数的近线性依赖,并进一步在CoRe数据库中验证了D̃与f_pk的近似EOS无关标度关系,表明并合后引力波确实携带了超出潮汐形变所能给出的最高密度信息。未来,这类参数化方法可拓展至更多声速特征参数,并用于训练代理模型或神经网络仿真器,从而高效联合多信使数据约束极端密度物态方程。

预印本 2026-07-17 · 收录 2026-07-20

02
优先级 95 · X射线双星与吸积致密天体 · 黑洞X射线双星 · X射线定时与能谱

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

黑洞X射线双星Swift J1727.8-1613中稳定的X射线回响滞后

Wei Yu, Sinan Allak, Zi-Xu Yang, et al.

原文摘要Abstract

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 amplitude, we focused on a frequency range in which the reverberation signal dominates and remains stable, thereby minimizing contamination from hard lags and phase-wrapping effects. Results. The soft lag amplitude increases rapidly from the LHS to the early HIMS and then stays near 10 ms throughout the HIMS. In the frequency range in which reverberation lags prevail, the lag shows little dependence on Fourier frequency. On the other hand, the observed low-frequency lags change from hard-lag dominated to soft-lag dominated, with amplitudes comparable to those measured at higher frequencies. Conclusions. These results suggest that the reverberation lag varies little during the HIMS, consistent with a relatively stable inner accretion geometry during this state. The apparent evolution of the lag amplitude from the LHS to the HIMS can be largely explained by the diminishing effect of hard lags and does not necessarily require significant changes in the intrinsic light-travel timescale. Swift J1727.8-1613 therefore provides a case in which the reverberation signal can be studied with reduced contamination over a broad frequency range, offering new insight into the evolution of the accretion geometry in black hole X-ray binaries.

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亮点

该源在HIMS中展现出异常稳定的回响滞后,与通常观测到的滞后幅度下降趋势相反;通过固定1–10 Hz频率区间测量,有效隔离了回响成分,表明表观滞后演化主要受硬滞后减弱的影响。

脉络与展望

该研究继承了此前对黑洞X射线双星回响滞后的观测工作(如 Kara+ 2019 对 MAXI J1820+070 的分析,Wang+ 2022 的样本研究),发现 Swift J1727.8-1613 在 HIMS 中软滞后幅度保持稳定,与常见趋势相悖。通过选用固定的高频区间最小化硬滞后和相位缠绕污染,为分离回响与传播涨落成分提供了新范例。未来结合 Zhan+ 2025 的蒙特卡罗辐射转移模拟,有望厘清回响滞后对内吸积几何变化的依赖,并推广至更多源的状态演化研究。

预印本 2026-07-17 · 收录 2026-07-20

03
优先级 90 · 引力波电磁对应体 · NSBH并合 · 引力波参数估计

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

离心率与高阶模对中子星-黑洞参数估计的影响

S. Tibrewal (Department of Physics, University of Texas at Austin), A. Jan (Department of Physics, University of Texas at Austin), A. Zimmerman (Department of Physics, University of Texas at Austin) et al.

原文摘要Abstract

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 hole observations; in contrast, neutron star-black hole systems produce longer in-band signals, enabling more precise measurements of eccentricity and leaving a distinct imprint on parameter inference. In this work, we present a systematic parameter-estimation study exploring the impact of eccentricity on inference using injections simulated with the state-of-the-art eccentric waveform model SEOBNRv5EHM. We find that for systems like GW200105_162426, the measurement precision of eccentricity and correlated parameters improves as eccentricity increases, yielding tighter constraints at larger eccentricities. For the highest eccentricity considered in this study, $e=0.25$, we recover eccentricity with $1σ$ uncertainty as low as $4\times10^{-4}$. In addition, the constraints on effective spin $χ_\mathrm{eff}$ and mass ratio $q$ improve relative to the quasi-circular case by factors of $\sim13$ and $\sim20$, respectively. On the other hand, we find no significant improvement in extrinsic parameters such as luminosity distance and sky localization, suggesting that for systems like GW200105_162426, the additional information provided by eccentricity in this sector is either negligible or degenerate with the information provided by higher-order modes.

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亮点

首次采用完整IMR离心波形模型SEOBNRv5EHM进行注入-恢复研究,量化了离心率对NSBH系统本征参数(质量比、有效自旋)的显著改善,并揭示了离心信息主要通过四极矩贡献而非高阶模,与高阶模信息互补。

脉络与展望

先前研究已指出引力波离心率可打破参数简并并提高测量精度(Favata+ 2022Gondán+ 2018),近期GW200105事件中离心率证据的报道(Morras+ 2026)推动了对NSBH系统离心效应更系统的探索。本文通过类GW200105注入实验,首次量化了离心率对质量比、自旋等本征参数的增益幅度(最高可达~20倍),并发现该增益源自离心动力学本身的时频结构,与高阶模贡献弱相独立。该结果意味着未来观测到的离心NSBH事件可为单源参数提供更强约束,有望用于区分动力学形成渠道(Stegmann and Klencki 2025Romero-Shaw+ 2025);但现阶段离心率测量仍受波形系统及先验选择影响(Clarke+ 2026),且外禀参数改善有限,需更高信噪比及下一代探测器联合高阶模观测进一步验证。

预印本 2026-07-17 · 收录 2026-07-20

04
优先级 90 · 引力波电磁对应体 · 多信使触发与联合

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

偏心率作为放大镜:偏心中子星-黑洞并合带来的高精度族群推断

A. Salvarese (Department of Physics, The University of Texas at Austin), H.-Y. Chen (Department of Physics, The University of Texas at Austin), A. Zimmerman (Department of Physics, The University of Texas at Austin), et al.

原文摘要Abstract

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 eccentric NSBH mergers, such as the component masses and spins, are much better measured than circular mergers with LIGO-Virgo-KAGRA (LVK) observatories. We explore how such eccentricity-enhanced parameter measurements can affect the inference of NSBH formation channels. We find that sharper measurements of the effective spin parameter $χ_{\rm eff}$ increase the fraction of systems for which negative values can be confidently identified, allowing for the clear measurement of a spin-orbit misaligned event every $\sim 2.5$ eccentric NSBH detections for an isotropically distributed population in the fifth LVK observing run (O5). Improved NS mass measurements provide better constraining power for NS mass distributions, potentially revealing structure and tightening the bounds that can be drawn on their upper and lower masses. Similarly, the recovery of a metallicity-dependent BH mass distribution is improved by eccentricity-enhanced measurements. Finally, we show that the proposed population-level eccentricity distribution for dynamical-formation channels can be tested by the end of O5.

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亮点

首次量化偏心率改进的参数测量对 NSBH 族群推断的影响;发现在 O5 灵敏度下,每约 2.5 个偏心事件即可明确识别一次负自旋,且能显著提升区分双峰/均匀质量分布和不同金属丰度模型的能力,并有望在 O5 结束前检验动力学形成的普适偏心率分布。

脉络与展望

孤立双星演化倾向于产生近圆形轨道,但 GW200105 的发现 Abbott+ 2021 及其后续偏心率分析提示动力学形成渠道的可能。近期研究 Tibrewal+ 2026 表明,偏心率能显著改善 NSBH 并合固有参数的测量精度。本文在此基础上探索了这些改进对族群推断的影响:包括更有效地识别负有效自旋、区分 NS 质量分布结构,以及恢复 BH 质量分布所蕴含的金属丰度信息 Broekgaarden+ 2021。未来,随着 O5 探测数量的增加,有望直接验证动力学并合的普适偏心率分布 Rozner+ 2026,从而为揭示 NSBH 的形成历史提供强有力的证据。

预印本 2026-07-17 · 收录 2026-07-20

05
优先级 80 · 太阳耀斑

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

可解释人工智能用于太阳耀斑预测:模型聚焦区域的定量磁场分析

Z. Zheng (School of Astronomy and Space Science, Nanjing University), Q. Hao (School of Astronomy and Space Science, Nanjing University), C. Li (School of Astronomy and Space Science, Nanjing University) et al.

原文摘要Abstract

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, current XAI studies in solar flare prediction are largely qualitative and lack systematic, theory-based, quantitative validation. We present a quantitative XAI framework that can decipher the physical basis of CNN-based solar flare prediction models. Using gradient-weighted class activation mapping (Grad-CAM), we identify model-focused regions (MFRs) in solar magnetograms. Then, we perform two key analyses to evaluate the predictive capability of magnetic parameters derived from MFRs and to quantitatively characterize their magnetic complexity. Our results reveal a strong physical correlation between MFRs and flare occurrence. Specifically, magnetic features extracted from MFRs demonstrate high predictive power for flares. Flare-producing active regions are characterized by magnetically complex configurations that are dominated by a single polarity rather than by balanced or purely unipolar structures. This finding is consistent with established physical theories of magnetic systems prone to flares. Our results suggest that CNNs can learn physically meaningful representations when trained on large-scale observations. Integrating XAI with quantitative magnetic field analysis improves the physical interpretability of deep learning-based flare prediction models, making them useful tools for prediction and modeling investigation in solar physics.

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亮点

亮点:首次对CNN耀斑预测模型的聚焦区域进行系统定量的磁场分析,揭示了这些区域与耀斑发生的物理关联,而非仅定性可视化。

脉络与展望

过去基于机器学习的太阳耀斑预测虽取得高性能,但多为黑箱模型。XAI技术如梯度加权类激活映射(Grad-CAM,Selvaraju+ 2017)已被引入耀斑预测,用于定位模型关注的关键区域(Huang+ 2018Yi+ 2021Sun+ 2022a),但这些研究多为定性分析,缺乏系统定量验证。本文发展了一个定量XAI框架,通过Grad-CAM识别模型聚焦区域(MFR),并从磁参数预测能力和磁复杂性两个角度进行物理验证。研究表明MFR的磁场信息能有效预测耀斑,且倾向于呈现单极主导的复杂极性结构,与物理理论一致。这一工作将XAI从定性解释推向定量物理验证,提升了深度学习耀斑预测模型的科学可信度,为未来构建可解释的物理约束模型提供了基础,并可能拓展至其他天体物理爆发现象的研究。

预印本 2026-07-17 · 接收 2026-07-17 · 刊出 2026-08-21 · 收录 2026-07-20

06
优先级 70 · X射线双星 · 吸积致密天体

Viscous Accretion Disks around Regular Black Holes Embedded in a Quintessence Dark Energy Field: Beyond the Novikov--Thorne Approximation

暗能量场中正则黑洞周围的粘性吸积盘:超越Novikov-Thorne近似

S. Dutta (Department of Applied Mathematics, Dinabandhu Andrews Institute of Technology and Management, Kolkata, West Bengal, India)

原文摘要Abstract

We develop a comprehensive relativistic framework for geometrically thin, optically thick Shakura--Sunyaev $α$-viscous accretion disks around rotating Hayward regular black holes embedded in a quintessence dark energy (DE) field. The static, spherically symmetric building blocks of our spacetime are each exact solutions of the Einstein field equations, sourced respectively by the Hayward non-linear electromagnetic field and a quintessence fluid with equation-of-state parameter $ω<-1/3$; we combine and rotate them following standard practice for this class of models, and we are explicit throughout about the resulting metric's phenomenological status. Abandoning the stress-free inner boundary of the Novikov--Thorne--Page (NTP) model, we analytically incorporate a non-zero viscous torque $\Tcal_{\rm in}$ at the innermost stable circular orbit (ISCO) via the relativistic vertical epicyclic frequency $\Obot(r)$. We prove that the bolometric efficiency $η=[1-E(\rISCO)]\times100\,\%$ is strictly independent of the viscosity parameter $α$ but sensitive to both the Hayward length scale $l$ and the DE density $ρ_0$, establishing a rigorous two-observable degeneracy-breaking strategy. At benchmark parameters ($j=0.4$, $l=0.5M_{\BH}$, $ρ_0=2\times10^{-4}$), the combined geometry yields $η=8.71\,\%$, substantially above the vacuum Kerr value $7.51\,\%$ at the same spin. The viscosity correction $δ\Fcal/\Fcal_{\rm NTP}$ diverges at $r\to\rISCO^+$, amplified by the geometric odification of the boundary pressure: the viscosity amplification ratio rises from $0.80$--$4.52\,\%$ (vacuum Kerr) to $0.87$--$6.76\,\%$ (Hayward+DE) at $α=0.1$, providing a clean, monotonic observational discriminator accessible to \textit{NICER} and \textit{NuSTAR}, independent of the bulk spectral normalisation.

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亮点

首次将正则黑洞、精质暗能量和非零ISCO内扭矩纳入统一框架,且严格证明η不依赖α而仅由几何决定,为通过效率限制黑洞参数提供理论依据;内边界扭矩发散在修正几何中被放大,提供了清晰、单调的模型鉴别特征。

脉络与展望

该工作在经典Novikov-Thorne-Page (NTP) 薄吸积盘模型 Novikov+ 1973 Page+ 1974 的基础上,引入了Hayward正则黑洞 Hayward 2006 和Kiselev精质暗能量场 Kiselev 2003,并抛弃了传统零应力内边界条件,代之以非零内扭矩 Agol+ 2000。旋转时空的构建遵循该领域的唯象惯例,但并非爱因斯坦场方程的严格解,如 Kamenshchik+ 2023 指出的,在正则核心附近存在偏离。该框架使辐射效率η与粘性参数α解耦,可独立限制黑洞几何,而粘性放大效应则为区分模型提供了清晰的观测诊断。未来可结合GRMHD模拟、精确垂直epicyclic频率计算以及X射线光谱拟合(如xspec)进一步提升模型的可靠性和预测能力。

预印本 2026-07-17 · 收录 2026-07-20

边缘相关 25 篇 · 低相关性展开 +
优先级 35 · 太阳耀斑

Solar Cycle Variation of the Distribution of Photospheric Magnetic Flux Features

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

原文摘要Abstract

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 power law provides the best representation of the data over the full solar cycle and we present the dependence of the power law exponents on the phase of the solar cycle. The nature of the observed flux distributions at different times during the solar cycle is significant because it could be used to try and infer information about solar magnetic field generation mechanisms. We discuss potential implications of a double power law distribution for solar magnetic field generation.

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光球磁通特征分布的太阳周变化 · 利用SDO/HMI数据统计分析光球磁通特征的分布及其在整个太阳周中的变化,发现双幂律分布最佳拟合数据,并揭示其指数随太阳周相位变化的依赖关系。

预印本 2026-07-17 · 收录 2026-07-20

优先级 30 · 多信使触发与联合

GW Microlensing: Degeneracy with Unlensed Precessing and Non-Spinning Gravitational-Wave Signals

Disha Hegde, Anupreeta More

原文摘要Abstract

With nearly 400 Gravitational Wave (GW) events detected by the LIGO-Virgo-KAGRA network and many more expected, similarities between signals produced by different astrophysical effects can complicate template-based searches and parameter estimation. In particular, GW modulations from spin precession can resemble the beating pattern induced by microlensing from compact objects with masses of $10$-$10^5,M_\odot$. We investigate this degeneracy and assess whether machine learning can distinguish between these effects. We generate 20,000 simulated GW signals for each class with a network optimal signal-to-noise ratio above 20 and train a convolutional neural network on time-frequency (Q-transform) spectrograms. The classifier achieves up to 95% accuracy in Gaussian noise and 82% in real detector noise. We also study classification between microlensed (ML) and unlensed non-spinning (UN) signals, as well as between unlensed non-spinning (UN) and unlensed precessing (UP) signals. While distinguishing UN from UP remains difficult even in Gaussian noise, ML vs. UN classification reaches up to 80% accuracy in real noise. We identify the regions of parameter space where the classifier performs best and evaluate the ML-UN network on real GW events, finding that the model trained on Gaussian noise generalizes better than the one trained on real noise. This work presents the first low-latency machine-learning pipeline for distinguishing microlensed from unlensed non-spinning GW signals.

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GW微引力透镜:与未透镜化进动和非自旋引力波信号的简并性 · 本文利用卷积神经网络基于Q变换时频谱图区分微透镜化与未透镜化引力波信号,研究其与进动信号的简并性,并首次提出低延迟机器学习管道,在真实噪声中分类准确率达82%。

预印本 2026-07-17 · 收录 2026-07-20

优先级 20 · AGN · 变脸AGN

22 Newly Identified Repeating Changing-look AGNs and Evidence for Extreme Broad-line Region Breathing

Litao Zhu, Zhongxiang Wang, Alok C. Gupta, et al.

原文摘要Abstract

Changing-look active galactic nuclei (CL AGNs) show the appearance or disappearance of broad emission lines on timescales of years. Among them, the repeating CL (RCL) AGNs may provide a clear clue for our understanding of the CL transitions because the same nucleus crosses some physical boundaries more than once. We search for RCL AGNs in known CL-AGN samples using long-term multi-band light curves, and selected 34 candidates for spectroscopic follow-up. We confirm 25 RCL AGNs, including 22 newly identified cases. Properties of these RCL AGNs are analyzed. The observed rest-frame intervals of the second transitions are mostly 3--4 yr, while the variations of the optical light curves suggest that some transitions might occur on timescales of several months. The latest spectra show that the on/off states correspond to higher/lower Eddington-ratio, in the expected direction relative to the parent CL-AGN samples. As seven RCL AGNs are well covered by nearly continuous single-band light curves, their on/off states can be found to follow multi-year optical excursions, and their Eddington ratios vary consistently with the photometric changes. We also find that the H$β$-only transitions occur at higher Eddington ratios than the transitions involving both H$α$ and H$β$, suggesting a line-dependent Broad-Line-Region (BLR) visibility threshold. These results support a picture in which different accretion-flow processes drive reversible changes in the central ionizing emissions, while the observed RCL transitions are produced by the BLR breathing across line-dependent visibility thresholds.

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22个新确认的重复变化型活动星系核及极端宽线区呼吸的证据 · 通过搜索并确认25个重复变化型活动星系核(其中22个新发现),分析其性质,发现Hβ-only转变发生在更高爱丁顿比,支持宽线区呼吸通过依赖于谱线的可见性阈值产生可逆转变的图景

预印本 2026-07-17 · 收录 2026-07-20

优先级 20 · 广义相对论 · 数值模拟 · 辐射碰撞

The weight of light: colliding pulses of radiation in General Relativity

Jorge Expósito Patiño, Vitor Cardoso, Hannes R. Rüter

原文摘要Abstract

We study the gravitational interaction of very strong pulses of electromagnetic radiation, up to and beyond gravitational collapse. We demonstrate the existence of very compact states close to the threshold of collapse, both for a single pulse, and a head-on collision of such pulses, and we measure their compactness to be above the maximum value proposed by the hoop conjecture. For a single pulse above the threshold of collapse, a fast black hole is produced. Depending on the amount of tuning, head-on collisions can form two horizonless states, two small black holes or one big black hole. Our results show that the gravitational interaction of massless fields can lead to nontrivial final or intermediate states, while giving rise to extremely high luminosity and compactness.

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光的重量:广义相对论中辐射脉冲的碰撞 · 通过数值模拟研究大能量电磁辐射脉冲的引力相互作用,发现靠近坍缩阈值的超致密状态,其致密性超过环假说上限,头对碰可形成无地平线态、双黑洞或单黑洞等结局。

预印本 2026-07-17 · 收录 2026-07-20

优先级 20 · AGN · 高红移星系

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

Sai Zhai, Huub Röttgering, Anniek J. Gloudemans, et al.

原文摘要Abstract

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 928 sources detected in both the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) and the LOw Frequency ARray (LOFAR) surveys. These matches are drawn from 55,109 spectroscopically confirmed LAEs and 27,625 radio sources. After applying completeness corrections, we obtain fAGN,radio = 1.77 $\pm$ 0.04% and fLya = 18.15 $\pm$ 0.14%. The fraction fAGN,radio increases from 0.4 $\pm$ 0.1% to 9.7 $\pm$ 1.3% with increasing Lya luminosity, while fLya rises from 0.7 $\pm$ 0.1% to 55.8 $\pm$ 14.5% with radio luminosity. `LAEs with radio AGN' and `optical AGN with Lya emission' show similar radio luminosities above the AGN threshold, although optical AGN have higher Lya luminosities. We find no significant correlation between Lya luminosity and either radio luminosity or spectral index. Lya line width increases with Lya luminosity but shows no correlation with radio size. Our results show that most Lya emission at 1.88 < z < 3.52 is powered by star formation, with radio AGN activity confined to a small luminous subset (1.77 $\pm$ 0.04%). The absence of correlations between Lya and radio properties suggests that Lya emission is governed primarily by host-galaxy gas properties rather than direct AGN jet coupling.

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红移1.88至3.52的射电探测Lyα发射体:AGN比例与Lyα发射 · 利用HETDEX和LOFAR数据,测量了1.88<z<3.52的Lyα发射体中射电AGN的比例和射电源中Lyα发射的比例,发现大多数Lyα发射来自恒星形成,AGN活动仅占一小部分。

预印本 2026-07-17 · 收录 2026-07-20

优先级 10 · 黑洞物理 · 拟正则模

Scalar quasinormal modes of Schwarzschild--anti-de Sitter black holes: spectral analysis and generalized boundary conditions

Davide Batic, Alan S. Cornell, Denys Dutykh

原文摘要Abstract

We study quasinormal modes (QNMs) of a minimally coupled massless scalar field on four-dimensional Schwarzschild--anti-de Sitter black holes using a Chebyshev spectral method. After compactifying the exterior domain, the radial problem is formulated as a quadratic matrix pencil in the dimensionless frequency. For the standard Dirichlet, or vanishing-field, boundary condition at the conformal AdS boundary, we reproduce the known scalar spectra across small, intermediate, and large black holes, including long overtone sequences and the expected approach to pure-AdS normal modes in the small black hole limit. We then deform the AdS boundary condition by imposing a generalized relation between the two independent asymptotic coefficients of the massless scalar. This deformation is treated as a generalized coefficient boundary condition for the massless scalar, and not as the usual alternative quantization for scalars in the Breitenlohner-Freedman window. The Dirichlet endpoint recovers the stable standard spectrum. For every non-Dirichlet value examined, and for representative small, intermediate, and large black holes, we find an additional mode with positive imaginary part, signaling a boundary-condition-induced instability. A near-Dirichlet refinement finds no finite critical angle down to the smallest deformation probed.

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史瓦西-反德西特黑洞的标量拟正则模:谱分析与广义边界条件 · 使用切比雪夫谱方法研究史瓦西-反德西特黑洞中标量场的拟正则模,并通过广义边界条件发现了边界条件导致的不稳定性。

预印本 2026-07-17 · 收录 2026-07-20

优先级 10

Hanbury-Brown Twiss effect, squeezed gravitons and the photon correlations

Massimo Giovannini

原文摘要Abstract

Unlike the gravitational waves classically generated by moving macroscopic masses, the diffuse backgrounds of gravitons originate most likely from zero-point fluctuations of the gravitational field amplified by the evolution of the space-time curvature. The resulting entangled states lead to specific second-order correlation effects that could be eventually detected. For a quantitative analysis of this empirical expectation we scrutinize the interactions between the cosmic gravitons and the fundamental mode of a quantized electromagnetic field confined inside a closed optical resonator with perfectly-reflecting walls. We show that the Hanbury-Brown Twiss correlations of the photons are insensitive to the degrees of second-order coherence of the gravitons even barring for the exceedingly small couplings of the problem. Since the degree of second-order coherence of the photons does not reflect the correlation properties of the gravitons, the statistical properties of the gravitons (and their super-Poissonian statistics) cannot be inferred, even in principle, from the intensity correlations of the cavity modes.

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汉伯里-布朗-特维斯效应、压缩引力子与光子相关性 · 论文研究了宇宙引力子与光学谐振腔内电磁场的相互作用,发现Hanbury-Brown-Twiss光子相关性对引力子的二阶相干度不敏感,因此无法从光子强度相关性推导引力子的统计性质。

预印本 2026-07-17 · 收录 2026-07-20

优先级 10 · 宇宙学模拟 · 数据门户

OpenCosmo: Community Portal and Analysis Framework for Flagship Cosmological Simulations

Patrick R. Wells, Michael Buelhmann, Patricia Larsen, et al.

原文摘要Abstract

Cosmology is an observational precision science, and detailed and scientifically rich simulations are necessary components of many analyses. These simulations are often computationally expensive and produce massive amounts of complex data. Sharing that data widely to enable further explorations, comparison with observations, and communication with general audiences is crucial to advancing the scientific frontier and engaging a broader community. In this paper, we introduce the OpenCosmo project, designed to provide flexible access and analysis modes to large cosmological simulation datasets. We make available an easy-to-use web-based data portal for retrieving downloadable subsets of flagship-scale cosmological datasets, and a sophisticated analysis library for further analysis on the returned data. OpenCosmo supports multiple levels of interaction -- from simple search and download to interactive exploration and computation -- by integrating with existing HPC and data infrastructure. Its architecture, based on Globus Compute, provides a scalable and adaptable framework that can be extended to other scientific domains seeking to couple data sharing with computational capability.

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OpenCosmo:旗舰宇宙学模拟的社区门户与分析框架 · 本文介绍了OpenCosmo项目,为旗舰级宇宙学模拟数据集提供基于网页的数据门户和分析框架,支持灵活访问和计算。

预印本 2026-07-17 · 收录 2026-07-20

优先级 10 · 修改引力 · 宇宙学

Comparison of $f(R,T)$ Gravity with Multiple Datasets

Vincent R. Siggia, Eric D. Carlson

原文摘要Abstract

We examine $f(R,T)=R+λT^ε$ gravity models by finding the best fit parameters for various values of $ε$. This is accomplished by analyzing data from the cosmic microwave background, baryon acoustic oscillation observations, cosmic chronometer, and Type Ia supernovae introducing correlations and radiation effects to our previous work. We find the probability distribution for the best fit model around the value of $ε=0.010^{+0.013}_{-0.021}$, consistent with the standard cosmological model value of $ε= 0$.

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f(R,T)引力与多数据集的比较 · 通过分析CMB、BAO、宇宙学计时器和Ia型超新星数据,检验了f(R,T)=R+λT^ε引力模型,发现最佳拟合参数ε=0.010^{+0.013}_{-0.021},与标准宇宙学模型一致。

预印本 2026-07-17 · 收录 2026-07-20

优先级 10 · 宇宙学 · 引力波

Constraining primordial non-Gaussianity and parity-violation through Scalar-Induced Gravitational Waves with next-generation ground-based interferometers

Ilaria Caporali, H. V. Ragavendra, Angelo Ricciardone, et al.

原文摘要Abstract

In this work, we investigate the prospects for probing primordial non-Gaussianity and associated symmetry of parity through scalar-induced gravitational waves (SIGWs), with third-generation gravitational-wave detectors. We develop a framework that accounts for contributions to the energy density spectrum of GWs arising from the scalar non-Gaussianity quantified by bispectrum and trispectrum, and perform parameter inference using simulated data from Einstein Telescope and Cosmic Explorer. The parity-odd component of the scalar trispectrum induces circular polarization in the stochastic gravitational-wave background (SGWB), providing a direct probe of parity-violation in the primordial Universe. We show that future interferometers can place competitive constraints on the parity-odd scalar trispectrum, along with the bispectrum and parity-even trispectrum. Moreover, we include the astrophysical contribution, which could act as a foreground for the SIGWs. We show that, despite the addition of such a foreground, we are still able to effectively constrain the cosmological parameters related to SIGWs and the astrophysical parameters as well.

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利用下一代地面干涉仪通过标量诱导引力波约束原初非高斯性和宇称破缺 · 本文开发了一个包含双谱和三谱贡献的框架,通过标量诱导引力波用下一代地面干涉仪约束原初非高斯性和宇称破缺,并展示了即使在存在天体物理前景的情况下也能有效约束相关参数。

预印本 2026-07-17 · 收录 2026-07-20

优先级 10 · 暗物质

Cosmological Evidence for Dark Axion-Dark Baryon Interactions from Apparent Phantom Crossing

Justin Khoury, Meng-Xiang Lin, Mark Trodden

原文摘要Abstract

Interactions between dark matter and dark energy can lead to an apparent phantom-crossing behavior that mimics the expansion history preferred by the latest cosmological observations from DESI baryon acoustic oscillations (BAO), Cosmic Microwave Background (CMB), and Type Ia supernovae (SNe Ia) data. In a previous paper [Khoury, Lin, and Trodden 2025 arXiv:2503.16415], we proposed a concrete particle physics realization of this idea, consisting of a strongly coupled dark sector in which a dark axion is coupled to dark baryons. In this paper, we investigate this idea further by comparing its predictions to the latest cosmological data. We implement the dark axion-dark baryon interaction model in a Boltzmann code and confront it with CMB, DESI DR2 BAO, and SNe Ia data. For the CMB+DESI DR2+DES-Dovekie combination, the best-fit model improves the fit relative to $Λ$CDM by $Δχ^2=-14.48$. The preferred solution exhibits a non-monotonic dark-matter mass evolution: the mass decreases between matter-radiation equality and recombination, while increasing over the BAO/SNe-sensitive epoch, leading to an apparent phantom crossing in an effective dark-energy description. Interestingly, the same dynamics produces an Early Dark Energy-like energy injection near matter-radiation equality, but in the data-preferred region this component is too small to raise $H_0$ enough to substantially reduce the current tension.

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暗轴子-暗重子相互作用的宇宙学证据:来自表观幻影穿越 · 本文通过对比最新CMB、DESI DR2 BAO和SNe Ia数据,检验了暗轴子-暗重子相互作用模型,发现其最佳拟合优于ΛCDM(Δχ²=-14.48),呈现出非单调暗物质质量演化和表观幻影穿越,但未能显著缓解哈勃常数张力。

预印本 2026-07-17 · 收录 2026-07-20

优先级 5 · 褐矮星 · 恒星大气 · 冷星光谱

Silicate Clouds, SiO, and Molecular Trends across the L-T Sequence: A JWST/MIRI LRS Spectral Library of Brown Dwarfs

Sam Barber, Stanimir Metchev, Genaro Suárez, et al.

原文摘要Abstract

We present the results of a survey program with JWST's MIRI LRS that obtained 5$-$14 $μ$m R~100 spectra of twenty-three L0$-$T6 dwarfs. This spectral type range spans the formation, growth, and sedimentation of silicate condensate clouds, as well as the appearance of methane and ammonia in the atmospheres of brown dwarfs. The initial onset of silicate absorption at spectral type L0 as well as the evolution of this feature with spectral type are both examined in unprecedented detail. We detect 7.5$-$9.5 $μ$m gas-phase SiO absorption for the first time in dwarf stars, with detections in M5.5$-$L2.5 dwarfs from combined Spitzer IRS and JWST spectra. This feature has previously been detected in K and M giants, with stronger absorption in these giants than in higher-gravity M dwarfs. In contrast, low-gravity L dwarfs show weaker SiO absorption than field-gravity L dwarfs. We also confirm water, ammonia, and methane absorption trends with spectral type previously seen in Spitzer IRS observations. We report the possible detection of CS2 in a T3.5 dwarf, although confirmation would require higher-dispersion spectroscopy. We find two newly resolved binaries, confirm two near-equal flux unresolved candidate binaries, and identify two additional possible non-equal flux binaries. After accounting for contamination by resolved and candidate binaries, we find that single field dwarfs are ~0.15$-$0.20 mag underluminous compared to existing empirical relations. The presented spectral library offers a spectrophotometrically calibrated basis for future interpretation of JWST MIRI spectra of brown dwarfs or of directly imaged or transiting exoplanets.

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跨越L-T序列的硅酸盐云、SiO和分子趋势:褐矮星的JWST/MIRI LRS光谱库 · 利用JWST/MIRI LRS对23颗L0-T6褐矮星进行5-14μm光谱巡天,首次在矮星中探测到气相SiO吸收,并构建了校准光谱库以研究硅酸盐云和分子趋势。

预印本 2026-07-17 · 收录 2026-07-20

优先级 5 · 基础物理

Probing Lorentz-invariance-violation with quantum coherence of Unruh-DeWitt detector

Yihao Wu, Xiaobao Liu, Zehua Tian

原文摘要Abstract

Testing Lorentz invariance violation (LIV) is notoriously difficult, as its characteristic energy scale, $M_\star$, in modified dispersion relations typically lies beyond current experimental reach. To enable a low-energy probe, we investigate the quantum coherence of an inertial Unruh-DeWitt (UDW) detector interacting with a massless scalar field with a Lorentz-violating dispersion relation $ω_{|\textbf{k}|}=|\textbf{k}|f(|\textbf{k}|/M_\star)$. Unlike the Lorentz-invariant case where quantum coherence is rapidity-independent, we find for the Lorentz-violating quantum field case the dynamics of detector's quantum coherence exhibits a strong dependence on its rapidity -- offering a potential low-energy signature of LIV. Applying this to the polymer-quantized scalar field theory inspired by loop quantum gravity, we show that the detector's quantum coherence exhibits a pronounced dependence on rapidity and undergoes a sharp transition near a critical rapidity $β_c \approx 1.3675$, a value within reach of existing facilities like the Relativistic Heavy Ion Collider. We also show how the detector's rapidity and its energy-level spacing enhance the response to the test of LIV. Our results establish quantum coherence as a sensitive and practical probe of LIV, providing a complementary avenue for testing quantum gravity-induced modifications to field theory.

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利用Unruh-DeWitt探测器的量子相干性探测洛伦兹不变性破坏 · 本文通过研究洛伦兹破坏色散关系下Unruh-DeWitt探测器量子相干性对快度的依赖,提出了一种低能探测洛伦兹不变性破坏的新方法,并在聚合物量子化场论中验证了其灵敏性和实用性。

预印本 2026-07-17 · 收录 2026-07-20

优先级 5 · 星系宇宙学 · 星系形态 · 不相关

Morphological Bias: How Ellipticals and Spirals Trace the Cosmic Web Differently

Paula S. Ferreira, Carlos A. P. Bengaly, Renyue Cen

原文摘要Abstract

We present a data-driven measurement of galaxy bias and scale-dependent relative bias for elliptical and spiral galaxies using angular auto- and cross-power spectra from DES and DESI Legacy Imaging Surveys DR8. We introduce the cross-tracer clustering ratio (CTCR), which uses the ratio of auto- to cross-power spectra to isolate the relative clustering of morphological tracers as a function of angular multipole $\ell$. Across both surveys, ellipticals are more strongly clustered than spirals; the cleanest CTCR constraints come from DESI, where the two morphological samples have better-matched redshift distributions. The difference is scale dependent: the relative bias is close to unity on large angular scales, $\ell \lesssim 50$, but increases toward smaller scales, reaching an average separation of $2.6σ$ at $\ell \sim 150-200$. A complementary linear-bias analysis confirms that ellipticals are positively biased relative to the matter field, while spirals are consistent with weak bias or anti-bias. Unlike narrowly selected LRG samples, our morphologically selected elliptical samples show little redshift evolution, consistent with a broader halo-mass distribution. The results are robust to two covariance estimators, contamination tests, luminosity splits, and comparisons with two N-body mock catalogs. These new findings provide empirical evidence that galaxy morphology imprints both the amplitude and scale dependence of galaxy bias, and establish CTCR as a useful observable for testing halo occupation and assembly-bias models with future imaging surveys.

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形态偏差:椭圆星系和旋涡星系追踪宇宙网的不同方式 · 本文利用DES和DESI巡天的角功率谱,测量椭圆和旋涡星系的星系偏差和尺度依赖的相对偏差,发现椭圆星系比旋涡星系有更强的正偏置且偏差具有尺度依赖性,并引入交叉示踪团簇比(CTCR)作为有效观测量。

预印本 2026-07-17 · 收录 2026-07-20

优先级 5 · 太阳物理

Oscillation Period Properties of Sunspots in the 8-10 $μ$m Infrared Band: A Multi-Dataset Analysis

Suo Liu

原文摘要Abstract

Sunspot oscillations probe magnetic-plasma interactions in the solar atmosphere. We investigate oscillation periods in six sunspot active regions observed in the 8-10 um band with the Accurate Infra-red Magnetic-field Solar Telescope (AIMS) at Lenghu Observatory. Light curves were extracted from umbra, penumbra, and quiet Sun regions. Wavelet analysis was applied using four methods: pixel-wise with mean/median aggregation, and spatial mean/median prior to analysis. The weighted mean period is more physically meaningful than the dominant period, better representing multi-mode oscillations. A consistent period sequence holds across all datasets: umbra (U) < penumbra (P) < quiet Sun (Q), with typical values of 260-313 s, 286-374 s, and 294-382 s. This pattern is recovered with 100% consistency by pixel-wise mean/median and spatial median methods. Spatial mean shows 1/6 full, 3/6 partial, and 2/6 inconsistency. Spatial smoothing increases periods by up to 21%, most strongly in the umbra. All peak ratios are below 0.3 (mean 0.14 +/- 0.03), confirming multi-mode oscillations. These results establish the 8-10 um band as a valuable diagnostic window for sunspot magneto-convection and wave propagation.

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8-10微米红外波段太阳黑子振荡周期特性:多数据集分析 · 利用AIMS望远镜在8-10 μm波段观测六个太阳黑子活动区,通过多种小波分析发现本影、半影和宁静太阳的振荡周期存在一致序列(本影<半影<宁静太阳),并证明加权平均周期比主导周期更具物理意义,确立了该红外波段作为研究太阳黑子磁对流和波传播的诊断窗口。

预印本 2026-07-17 · 收录 2026-07-20

优先级 5 · 宇宙学 · 暗能量

On dark sector scalar field theories driven by cosmological $c$-fields

Alex E. Bernardini, Orfeu Bertolami

原文摘要Abstract

The interplay of Hoyle-Narlikar (HN) creation field cosmology and scalar field models for the dark sector, including the generalized Chaplygin Gas (GCG), is investigated . Though originating from distinct theoretical frameworks, both the inclusion and the non-inclusion of the creation field degree of freedom (DoF) involve a scalar DoF, which addresses some of the limitations of the standard $Λ$CDM model. Using a Lagrangian scalar field formulation and the first-order Hamiltonian reconstruction method, the HN $c$-field dynamics is shown to be encompassed by the GCG equation of state through an equivalent modified scalar field theory. Late-time acceleration and stability of linear perturbations are derived within this unified description. Our results suggest that creation field cosmologies may be embedded in a broader class of scalar field models which encompasses subtle modifications to the Hubble expansion rate and related physical observables.

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关于宇宙学c场驱动的暗部门标量场理论 · 本文通过标量场方法统一描述了Hoyle-Narlikar创造场宇宙学与广义Chaplygin气体模型,并推导了晚期加速与线性扰动的稳定性。

预印本 2026-07-17 · 刊出 2026-07-17 · 收录 2026-07-20

优先级 5 · 原行星盘 · 行星形成 · 盘自引力

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

V. Pezzotta, S. Facchini, A. F. Izquierdo, et al.

原文摘要Abstract

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 masses, disk masses, and scale radii for the disks around HD 97048 and WaOph 6. We obtain $M_\star=2.226 ^{+0.054}_{-0.049}\ M_\odot$, $M_\mathrm{d}=0.3 ^{+0.055}_{-0.061}\ M_\odot$ and $R_\mathrm{c}=172 ^{+24}_{-14}$ au for HD 97048, and $M_\star=0.956\ ^{+0.006}_{-0.006}\ M_\odot$, $M_\mathrm{d}=0.21 ^{+0.045}_{-0.038}\ M_\odot$ and $R_\mathrm{c}=647 ^{+193}_{-155}$ au for WaOph 6. We also measure the corresponding gas-to-dust and disk-to-star mass ratios. We efficiently extend the dynamical method to characterize embedded sources exhibiting features of absorption, for which a careful analysis is required to avoid biases in the retrieved velocity profiles. We prove the importance of including a beam smearing correction to the curves: if not, this observational effect can systematically bias the velocity profiles, altering the disk mass estimates up to $\sim45\%$. We provide comprehensive estimates of the systematic uncertainties on the best-fit parameters by bootstrapping over both the retrieved geometry and 2D thermal structure of the two disks: the overall uncertainty on the disk masses is $\sim20\%$. Finally, we investigate the connection between disk stability and the appearance of spiral morphologies in the mm continuum emission, by comparing the Toomre parameter of all dynamically weighed disks to date, showing that disks with mm-dust spirals have systematically lower values of Q.

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扩展动态质量测量:探究引力不稳定性作为毫米尘埃螺旋的可能起源 · 通过改进的动力学模型精确测量了HD 97048和WaOph 6两个原行星盘的质量,并发现毫米尘埃螺旋结构盘的Toomre参数系统性更低,支持引力不稳定性作为其可能起源。

预印本 2026-07-17 · 收录 2026-07-20

优先级 5 · 黑洞散射 · 超辐射 · 理论物理

Massless scalar scattering by Kerr-Bertotti-Robinson black holes:transparent-end channels and superradiance

Hai Huang, Xudong Sun, Juhua Chen

原文摘要Abstract

We formulate and numerically solve the real-frequency scattering problem for a neutral, minimally coupled, massless scalar on the rotating Kerr--Bertotti--Robinson (Kerr--BR) black-hole geometry, using a specified transparent boundary condition at the coordinate end. Since the Maxwell stress tensor of the background is traceless, the minimally coupled wave equation reduces to the four-dimensional conformal wave equation, enabling exact Carter-like separation after scaling the scalar field by the conformal factor. Unlike the asymptotically flat case, the coordinate end $r\to\infty$ lies at a finite tortoise distance. We show that the resulting reflection data are conditional on this boundary prescription rather than defining a unique, observer-independent cross section. Within the transparent-end model,open-channel superradiance is governed by a double-gate mechanism requiring both the local horizon condition and the outer propagation condition $q_\infty^2>0$. At the benchmark spin $a/M=0.9$, the co-rotating dipole amplification decreases as the external magnetic field increases. Crucially, the field narrows and closes the open superradiant window at $BM\simeq0.243$. Near the propagation threshold, the amplification coefficient vanishes linearly with the outer wave number.

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Kerr-Bertotti-Robinson黑洞的无质量标量散射:透明端通道与超辐射 · 本文通过数值求解旋转Kerr-BR黑洞几何中无质量标量场的实频散射问题,采用透明边界条件,揭示了开放通道超辐射受双重门控机制控制,并发现外磁场会缩小并关闭超辐射窗口。

预印本 2026-07-17 · 收录 2026-07-20

优先级 5 · CMB · SZ效应 · 宇宙学 · 再电离

Constraints on the remote quadrupole field from the polarized Sunyaev Zel'dovich effect

Jordan Krywonos, Matthew C. Johnson, Elena Pierpaoli, et al.

原文摘要Abstract

The polarized Sunyaev Zel'dovich (pSZ) effect is a cosmic microwave background (CMB) polarization anisotropy induced by Thomson scattering from free-electrons in non-linear structure. The pSZ signal is determined by the distribution of ionized gas tracing the cosmic web and the CMB quadrupole at the location of free-electrons - the remote quadrupole field. Measuring the pSZ effect provides a consistency check of the optical depth to reionization and sheds light on the anomalous nature of the large-scale CMB temperature anisotropies, such as the low observed CMB temperature quadrupole. In this paper, we demonstrate that a CMB-CMB-galaxy bispectrum summarizes several existing pSZ statistics, and that in our observable Universe the ideal galaxy sample to detect pSZ is at $z \sim 1-2$. We evaluate the bispectrum using CMB data from Planck and ACT with galaxy density from the unWISE galaxy redshift catalog as well as Planck cosmic infrared background (CIB) maps. We do not make a statistically significant detection of the pSZ effect, which is consistent with the expected O$(1)$ signal-to-noise from this data combination. The measured amplitude of the pSZ bispectrum provides constraints on the optical depth bias associated with large-scale structure (the amplitude of the pSZ signal) of $b_q=1.02 \pm 2.64$, the optical depth to reionization of $τ_{\rm rei} = -0.01 \pm 0.14$, and the tensor-to-scalar ratio $r$ of $σ_r \sim 150$ ($n_t = 0$) or $σ_r \sim 3$ ($n_t = -1$). We forecast that future measurements could tighten the constraints on these quantities by roughly a factor of 3, which is sufficient to provide independent confirmation of the low CMB quadrupole and the optical depth to reionization.

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极化Sunyaev Zel'dovich效应对远程四极场的约束 · 通过CMB-CMB-星系双谱对极化SZ效应进行约束,未显著探测到信号,给出了对远程四极场振幅、再电离光学深度和张量标量比的限制,并预期未来测量可将约束收紧约3倍。

预印本 2026-07-17 · 收录 2026-07-20

优先级 5

Localized Vector Modes on Local Cosmic Strings

Sergio Alameda-Calvo, Jose J. Blanco-Pillado, Jose Queiruga

原文摘要Abstract

We investigate the dynamics of vector excitations localized on cosmic strings in the Abelian-Higgs model. These confined gauge field fluctuations behave as massive vector degrees of freedom propagating along the string. We show that they remain bounded for all values of the scalar self coupling $λ$, including parameter regimes in which the previously studied conventional shape mode is no longer present. After determining their spectra and spatial profiles, we analyze their decay through nonlinear coupling to bulk radiation. Their amplitudes exhibit the characteristic power law relaxation associated with non-linear radiation. For sufficiently large $λ$ the scalar radiation channel becomes kinematically inaccessible and the decay is instead mediated by quasinormal modes which can be interpreted as Feshbach resonances of the string. We then study the full $3+1$ dimensional dynamics of the vector-excited string. Field theory simulations reveal a parametric instability between the vector mode and the Goldstone sector. In contrast to the shape mode, the vector mode resonantly excites both transverse directions simultaneously. In addition, we build an effective model that captures the instability and identifies the nonlinear couplings responsible for it. Our results show that vector excitations constitute a long-lived massive degree of freedom with a non-trivial role in the dynamics of local strings.

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局域宇宙弦上的局域矢量模式 · 研究了阿贝尔-希格斯模型中局域宇宙弦上矢量激发的动力学,证明其所有参数下保持有界,分析了谱、非线性衰变及与戈德斯通扇区的参数不稳定性,揭示矢量模式是弦动力学中的长寿命有质量自由度。

预印本 2026-07-17 · 收录 2026-07-20

优先级 5 · 宇宙学 · 大尺度结构 · 非高斯性

Large deviations for halos and voids: beyond perturbative non-gaussianities

Martin Teuscher, Ruth Durrer, Julien Grain, et al.

原文摘要Abstract

The excursion-set formalism provides a key connection between primordial density fluctuations and the abundance of cosmic structures such as dark matter halos and voids, traditionally assuming Gaussian random walks. In this work, we extend this framework to fluctuations whose distribution presents strongly non-Gaussian tails. Such tails are beyond the reach of perturbative approaches to primordial non-Gaussianity based on moment expansion. We address the problem with rigorous, analytical derivations relying on the large deviation principle, suited for the study of rare fluctuations. We derive new first-passage time distributions for random walks with non-Gaussian statistics and obtain updated predictions for the halo mass function. We also study the two-barrier problem relevant to cosmic void formation, leading to a new analytical prediction for the void size function, with improved accuracy on large scales. Our results demonstrate the potential of large deviation techniques as a bridge between inflationary scenarios, often leading to strongly non-Gaussian tails, and late-Universe observables.

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晕和空洞的大偏差:超越微扰非高斯性 · 利用大偏差原理,将excursion-set理论推广到强非高斯尾部,推导出新的首次通过时间分布,并更新了暗物质晕质量函数和宇宙空洞大小函数的解析预言。

预印本 2026-07-17 · 收录 2026-07-20

优先级 0

Update on the Physics of the Cosmic Microwave Background (2015-2025)

Martin Bucher

原文摘要Abstract

We review the present status of observations of the Cosmic Microwave Background. This book chapter is an update to an earlier review "Physics of the Cosmic Microwave Background Anisotropy" that appeared a decade ago in the compilation "One Hundred Years of General Relativity: From Genesis and Empirical Foundations to Gravitational Waves, Cosmology and Quantum Gravity." The earlier contribution summarized the state of the field then as well as the underlying cosmology and gravitational physics. This contribution reports on what new has occurred in the field during the intervening time 2015-2025. We also review future prospects.

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宇宙微波背景物理学的更新(2015-2025) · 更新了2015至2025年间宇宙微波背景观测的现状与未来展望。

预印本 2026-07-17 · 收录 2026-07-20

优先级 0

Radial velocity and atmospheric parameter calculations for the GaiaNIR spectrograph

Szabolcs Mészáros, David Hobbs, Anna Liptrott, et al.

原文摘要Abstract

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 from the BOSZ library across a wide range of stellar parameters, with resolutions varying from 5000 to 20000. By cross-correlating these mock observations with ideal templates, we assessed the statistical scatter of velocity residuals to isolate six candidate windows for further atmospheric parameter testing. Results. Our analysis finds that the 1926 - 1968 nm window at R = 16100 - 20100 in the K-band is the preferred strategic choice, because it has the potential to reach radial velocity precision for the brightest FGKM stars of about 160 - 260 m/s depending on resolution, while providing precision of the atmospheric parameters close to Gaia's Radial Velocity Spectrometer. We also identified a second region between 1158 and 1202 nm (R = 9300 - 11600), that has slightly lower radial velocity precision, but at a wider temperature range than the K-band. Both regions make it possible to derive abundances of ten species at these resolutions: O, Na, Mg, Si, Ca, Ti, V, Cr, Mn, Ni in the K-band, and Mg, Si, K, Ca, Ti, V, Cr, Mn, Co, Ni between 1158 - 1202 nm. Conclusions. The K-band delivers sufficiently precise measurements for the mission's primary cool star targets while taking advantage of significantly lower interstellar extinction, enabling the mapping of the dust-obscured regions of the Milky Way.

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盖亚近红外光谱仪的径向速度和大气参数计算 · 本文通过生成合成光谱并交叉相关分析,为GaiaNIR光谱仪选定了最佳工作波段(K波段等),并证明其能高精度测量径向速度、大气参数和多种元素丰度,从而有效绘制银河系尘埃遮蔽区域。

预印本 2026-07-17 · 收录 2026-07-20

优先级 0

Optical and Thermodynamic Signatures of Lorentz Symmetry Breaking in Bumblebee AdS Black Holes

Behzad Eslam Panah, Abdullah Guvendi, Semra Gurtas Dogan, et al.

原文摘要Abstract

We investigate the impact of spontaneous Lorentz symmetry breaking on scalar wave propagation, null geodesics, and thermodynamic behavior of four-dimensional asymptotically AdS black holes in bumblebee gravity. The static, spherically symmetric solutions are characterized by a dimensionless parameter $\ell > -1$ arising from the vacuum expectation value of the bumblebee vector field, which globally rescales the radial geometry. Massless scalar fields are analyzed via the radial Klein--Gordon equation cast into a generalized Helmholtz form, yielding an effective frequency-dependent refractive index that identifies oscillatory and evanescent regions, classical turning points, and confinement induced by curvature and Lorentz violation. In the high-frequency limit, wave propagation coincides with null geodesics, with $\ell$ controlling radial scaling and governing the geometric-optics limit. The AdS boundary reflects waves, while the horizon acts as a one-way absorber. Thermodynamic analysis in non-extended and extended phase spaces confirms the first law and Smarr relation, with $\ell$ influencing heat capacity, free energy, and stability. \textcolor{black}{Modeling these black holes as heat engines, we construct explicit cycles and show that efficiency increases with $\ell$, leading to an upper bound imposed by $η\leq 1$. Our results provide a framework connecting Lorentz violation, wave propagation, geometric optics, and AdS black hole thermodynamics in bumblebee gravity.

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大黄蜂AdS黑洞中洛伦兹对称性破缺的光学和热力学特征 · 本文研究了自发洛伦兹对称性破缺对bumblebee AdS黑洞的标量波传播、零测地线和热力学行为的影响,发现破缺参数ℓ会改变热容、自由度和稳定性,且以黑洞为热机时其效率随ℓ增加并受η≤1约束。

预印本 2026-07-17 · 收录 2026-07-20

优先级 0 · 宇宙学 · 大尺度结构

Standard Reconstruction Shifts the Optimal Input Scale for CNN-Based Density-Field Reconstruction

Koichiro Nakashima, Kiyotomo Ichiki, Atsushi J. Nishizawa

原文摘要Abstract

We investigate convolutional neural network (CNN) methods for reconstructing the high-redshift density field from late-time large-scale structure, focusing on how the physical scale of the CNN input changes when standard first-order reconstruction is applied beforehand. Using dark-matter-only $N$-body simulations, we compare three approaches: a single-input CNN, a dual-input CNN combining two physical scales, and a single-input CNN applied to the density field after standard reconstruction. We vary the physical side length of the input sub-box over $L_\mathrm{sub}\sim38$-$380~h^{-1}\mathrm{Mpc}$ while keeping its numerical size fixed at $39^3$ voxels, allowing us to examine the trade-off between spatial context and resolution. For the CNN applied directly to the evolved density field, the reconstruction performs best at $L_\mathrm{sub}\sim150$-$200~h^{-1}\mathrm{Mpc}$. After standard reconstruction, however, the preferred scale shifts to $L_\mathrm{sub}\sim38$-$114~h^{-1}\mathrm{Mpc}$. The single-input CNN after standard reconstruction consistently outperforms both the single- and dual-input CNNs without standard reconstruction according to the normalized loss, density probability distribution, Kullback-Leibler divergence, residual field, and Fourier-space correlation. These results indicate that coherent large-scale displacements are more efficiently recovered by perturbative reconstruction, while the CNN is better suited to modelling the remaining quasi-linear and non-linear evolution on smaller scales. The preferred post-reconstruction input range includes the effective receptive scale of approximately $60~h^{-1}\mathrm{Mpc}$ adopted in previous hybrid reconstruction studies. Our findings therefore support a physically motivated separation of scales between analytic and data-driven reconstruction and demonstrate the advantage of combining the two approaches.

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标准重建改变基于CNN的密度场重建的最优输入尺度 · 通过模拟对比不同输入尺度的CNN密度场重建方法,发现标准重建使最优输入尺度减小至约38-114 h⁻¹Mpc,并显著提升重建性能,支持解析与数据驱动方法在尺度上的分离

预印本 2026-07-17 · 收录 2026-07-20