研究動向

astro-ph.HE2026年8月12日

XRISM Spectroscopy of Variable Accretion-driven Disk Winds in NGC 4151: When, Where, and How Fast Outflows are Launched

Xin Xiang, Jon Miller, Missagh Mehdipour, Ehud Behar, W. Niel Brandt, Laura Brenneman, Luigi Gallo, Elias Kammoun et al.

X-ray observations probe the inner accretion flow within active galactic nuclei, revealing the highest gas column densities and fastest winds. The most diverse winds yet revealed with the Resolve calorimeter spectrometer aboard XRISM are found in NGC~4151, a nearby Seyfert-1 AGN that may qualify as a ``changing-look'' source (CLAGN). Herein, we report on wind variability in 14 XRISM observations of NGC~4151, summing to 0.9~Ms of exposure over a period of 395 days. We examined the dependence of k…

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astro-ph.EP2026年8月12日

Formation of multiple dust rings and gaps in protoplanetary discs by a single migrating planet. A parameter study in locally isothermal discs

Sören C. Meiners, Kim M. Weiskopf, Thomas Rometsch, Cornelis P. Dullemond

ALMA observations show that large protoplanetary discs usually contain multiple concentric dust rings separated by dark gaps. A natural explanation is dust-trapping at the edges of gaps opened by newly formed planets. However, planets typically migrate inward on timescales shorter than disc lifetimes, seemingly at odds with rings at large radii. We aim to investigate the conditions under which migrating planets can form long-lived, multi-ringed structures out to $r\sim 150$ au to constrain the p…

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astro-ph.EP2026年8月12日

Formation of multiple dust rings and gaps in protoplanetary discs by a single migrating planet. A parameter study in locally isothermal discs

Sören C. Meiners, Kim M. Weiskopf, Thomas Rometsch, Cornelis P. Dullemond

ALMA observations show that large protoplanetary discs usually contain multiple concentric dust rings separated by dark gaps. A natural explanation is dust-trapping at the edges of gaps opened by newly formed planets. However, planets typically migrate inward on timescales shorter than disc lifetimes, seemingly at odds with rings at large radii. We aim to investigate the conditions under which migrating planets can form long-lived, multi-ringed structures out to $r\sim 150$ au to constrain the p…

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astro-ph.HEastro-ph.SRgr-qc2026年8月12日

A Diverse Distribution of Black Hole Spins from Stable Mass Transfer

Linhao Ma, Jakub Klencki, Eliot Quataert, Lieke van Son

Gravitational wave observations have found over 300 merging binary black holes, yet their origins remain uncertain. Recent work showed that many may come from isolated stellar binaries whose orbits shrink through stable mass transfer. If true, their spins may help to distinguish this channel from other formation pathways. We investigate the tidal spin up of black hole progenitor stars with detailed modeling of binaries undergoing stable mass transfer. We calculate the tidal torques by solving ti…

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astro-ph.HE2026年8月12日

ATLAS22kjn (AT 2022fpx): A Coronal Line Emitter with an Early Light Curve Bump and Mid-Infrared Dust Echo

Athena C. Engholm, Jason T. Hinkle, Benjamin J. Shappee, Katie Auchettl, Dhvanil D. Desai, Willem B. Hoogendam, Christopher S. Kochanek, Nicholas Earl et al.

We present an analysis of ATLAS22kjn (AT 2022fpx), whose high-ionisation coronal lines (CLs) and pre-peak light curve bump provide distinctive opportunities to investigate the physical mechanisms powering tidal disruption events (TDEs). In addition to CLs, the optical spectra show common TDE features, including a strong, blue continuum and broad Balmer and He II lines. The CLs appear before UV/optical light curve peak, preceding the detection of X-rays by $\sim 300$ days and persisting after X-r…

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astro-ph.IMastro-ph.EPastro-ph.GAastro-ph.SR2026年8月12日

Early Exploration of the Scientific Discovery Space for the Habitable Worlds Observatory

Courtney D. Dressing, Danica Adams, Evelyne Alecian, Gagandeep Anand, Giada Arney, Sarah Gomes Aroucha Barbosa, Martin Barstow, Joanna K. Barstow et al.

The Habitable Worlds Observatory (HWO) is a future NASA flagship mission concept identified by the Astro2020 Decadal Survey as the highest priority for large space missions. HWO should conduct "transformative astrophysics" and search for biosignatures in the atmospheres of approximately 25 potentially Earth-like planets. To further the early-stage development of HWO, NASA formed the Science, Technology, Architecture Review Team (START). In turn, START invited the scientific community to join wor…

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astro-ph.IMastro-ph.SR2026年8月12日

Eclipses by Artificial Satellites to Measure the Angular Sizes of Stars

Leo W. H. Fung, Albert Wai Kit Lau, Richard Massey, George F. Smoot

Direct measurements of the angular sizes of stars (other than our Sun) are inherently limited by telescopes' optical diffraction limit. The spatial diffraction limit can be overcome by using time-domain information when stars are `eclipsed' by anything moving in the foreground: artificial satellites or the Moon (known as `lunar occultation imaging'). Here we analyse the angular resolution achievable by high-speed photon counting devices, when stars are eclipsed for several microseconds by one of…

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gr-qcastro-ph.HEastro-ph.IM2026年8月12日

All You Need is not $Ω_\mathrm{gw}$: Beyond the Mean of the Cross-Correlation Estimator when Searching for an Astrophysical Gravitational-Wave Background

Haowen Zhong, Francesco Iacovelli, Vuk Mandic, Emanuele Berti

Searches for the stochastic gravitational-wave background (SGWB) using ground-based detectors rely heavily on the cross-correlation estimator $\bar C_f$, whose statistical properties determine the theoretical foundation for inference frameworks built on it. Past analyses usually assume Gaussianity of $\bar C_f$, but this assumption has not been systematically tested for a background of astrophysical origin like the one produced by compact binary coalescences. In this work, we decompose $\bar C_f…

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astro-ph.IM2026年8月12日

High-temperature photovoltaics for solar-electric Oberth maneuvers: ton-class payload feasibility for interstellar-precursor missions

Nadim Maraqten, Willem van Lynden, Carlos Gómez de Olea Ballester, Andreas M. Hein

In-situ exploration beyond the giant planets remains rare because timely Solar System escape demands very high specific orbital energy, which existing concepts typically achieve only with small payloads, super-heavy launchers, or nuclear-powered propulsion. Motivated by laboratory demonstrations of high-intensity, high-temperature (HIHT) solar cells operating near $400\,^{\circ}\mathrm{C}$, we assess a solar-electric Oberth maneuver that concentrates thrust near a $0.3\,\mathrm{AU}$ perihelion.…

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astro-ph.SRastro-ph.EP2026年8月12日

Intense but Harmless: Exo-Space Weather Around an M Dwarf with a Single-Hemisphere Dynamo

Zheng Sun, Julián D. Alvarado-Gómez, Hui Tian, Ofer Cohen, Jeremy J. Drake, Katja Poppenhäger, Yue-Hong Chen

M dwarfs are among the most promising host stars in the search for habitable exoplanets. However, their active atmospheres drive intense magnetic activity, including energetic flares and possibly coronal mass ejections (CMEs), which may pose serious threats to planetary habitability. In this study, we perform three-dimensional magnetohydrodynamic (MHD) simulations of CMEs on a fully convective M dwarf with a rotation period of 30 days, corresponding to the moderate-rotation regime. The magnetic…

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astro-ph.EP2026年8月12日

Opposition effect of comet 28P/Neujmin observed with Subaru Hyper Suprime-Cam

Takafumi Ootsubo, Hideyo Kawakita, Tadafumi Takata, Junko Furusawa, Hisanori Furusawa, Tsuyoshi Terai, Toshihiro Kasuga, Akira Keida et al.

We present an observational study of the nucleus of comet 28P/Neujmin at a heliocentric distance exceeding 10 au, where coma contamination is effectively minimized. Observations were conducted in the $g$, $r$, and $y$ bands with the Hyper Suprime-Cam (HSC) on the 8.2-m Subaru Telescope. The measured colors, $g - r = 0.67\pm0.17$ and $r - y = 0.41\pm0.19$, yield a spectral index of $S' = 8.8\pm4.2\%/100$ nm, comparable to that of D-type asteroids. By incorporating new observational data at a phas…

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astro-ph.SR2026年8月11日

Gravity modes and potential evidence for Rossby Waves in late O-type supergiants

Lydia S. Cidale, Alejandra Christen, Aldana Alberici Adam, Suryani Guha, Alex Lobel, Gunther F. Avila Marin, Michaela Kraus, Alejandro H. Corsico et al.

The properties of O-type supergiant stars remain largely unexplored. By analysing their light variations, we can unravel underlying physical phenomena, such as binarity, stellar pulsations, and rotation modes. This study aims to analyse the TESS light curves of 3 O-type supergiants to identify periodic signatures and gain deeper insights into their internal dynamics and structure. Our primary goal is to search for the presence of rotational modulation and possible evidence of Rossby waves. A per…

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astro-ph.SR2026年8月11日

Gravity modes and potential evidence for Rossby Waves in late O-type supergiants

Lydia S. Cidale, Alejandra Christen, Aldana Alberici Adam, Suryani Guha, Alex Lobel, Gunther F. Avila Marin, Michaela Kraus, Alejandro H. Corsico et al.

The properties of O-type supergiant stars remain largely unexplored. By analysing their light variations, we can unravel underlying physical phenomena, such as binarity, stellar pulsations, and rotation modes. This study aims to analyse the TESS light curves of 3 O-type supergiants to identify periodic signatures and gain deeper insights into their internal dynamics and structure. Our primary goal is to search for the presence of rotational modulation and possible evidence of Rossby waves. A per…

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astro-ph.COastro-ph.HE2026年8月11日

Fitting trends in quasar emission and absorption line redshifts

Netra K Subramanian, Prasad Subramanian, Nimisha G Kantharia

The spectrum of a quasar consists of a few emission lines whose wavelengths are shifted by similar redshifts and numerous absorption lines whose wavelengths are shifted by different redshifts. Hence each quasar is characterised by an emission line redshift and the absorption lines redshifts are all less than the emission line redshift. The distribution of observed absorption line redshifts ($z_{abs}$) with respect to emission line redshift ($z_{em}$) for a large sample of quasars shows a systema…

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astro-ph.COastro-ph.HE2026年8月11日

Fitting trends in quasar emission and absorption line redshifts

Netra K Subramanian, Prasad Subramanian, Nimisha G Kantharia

The spectrum of a quasar consists of a few emission lines whose wavelengths are shifted by similar redshifts and numerous absorption lines whose wavelengths are shifted by different redshifts. Hence each quasar is characterised by an emission line redshift and the absorption lines redshifts are all less than the emission line redshift. The distribution of observed absorption line redshifts ($z_{abs}$) with respect to emission line redshift ($z_{em}$) for a large sample of quasars shows a systema…

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astro-ph.SR2026年8月11日

Pulsation periods reveal tension between theoretical and empirical radii for classical Cepheids in eclipsing binary systems

O. Ziółkowska, R. Smolec, R. Singh Rathour, V. Hocdé

Context. With their precisely determined physical parameters, classical Cepheids in eclipsing binary systems are often used to constrain stellar evolution and pulsation theories. To this end, their position in the HR diagram, effective temperature and luminosity, and radius are commonly used when matching best-fitting evolutionary models. However, the pulsation period of Cepheids, the most precise observable, is rarely used in such studies. Aims. We explore how including the pulsation period as…

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astro-ph.GA2026年8月11日

The Radcliffe Wave is not alone in the Local System

V. V. Bobylev, A. T. Bajkova

The spatial distribution of open star clusters (OSCs) younger than 30 million years old in the Local System was studied. It was shown for the first time that a significant number of OSCs belong to the recently discovered Vela Ridge gas and dust supercloud. The most intriguing property of this sample of OSCs is the presence of periodic perturbations in their vertical coordinates with a maximum amplitude of 47 pc and a wavelength of 1.1 kpc. Thus, the discovered chain of young OSCs is analogous to…

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astro-ph.GA2026年8月11日

The Radcliffe Wave is not alone in the Local System

V. V. Bobylev, A. T. Bajkova

The spatial distribution of open star clusters (OSCs) younger than 30 million years old in the Local System was studied. It was shown for the first time that a significant number of OSCs belong to the recently discovered Vela Ridge gas and dust supercloud. The most intriguing property of this sample of OSCs is the presence of periodic perturbations in their vertical coordinates with a maximum amplitude of 47 pc and a wavelength of 1.1 kpc. Thus, the discovered chain of young OSCs is analogous to…

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astro-ph.SR2026年8月11日

Observational Insights into Post-Main-Sequence Rotation and Magnetism: 20 Years of Science, from the Subgiant to the White Dwarf Phase

Emily Hatt

Rotation and magnetism are important phenomena to consider when trying to understand stars. By shaping the structure and chemical mixing in the interior of stars, they can induce significant changes in both their fundamental and observable properties. Despite this, our theoretical picture of how rotation and magnetism evolve throughout the stellar lifecycle remains incomplete. Gaps in our understanding are particularly stark for evolved stars, where slow rotation rates and weak magnetic fields m…

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astro-ph.SRastro-ph.IM2026年8月11日

Spectroscopic Binary Detection as Agent-Callable Tools: Detecting 40,000+ Main-Sequence Binary Candidates from SDSS DR19 APOGEE Spectra

Serat M. Saad, Yuan-Sen Ting

Unresolved binaries are common in spectroscopic surveys, and their blended light biases the parameters inferred for them. Methods to detect them exist, but applying one to a new data release is limited mostly by operating know-how that is rarely written down. We package the double-lined spectroscopic binary decomposition of El-Badry et al. (2018b) for reuse on APOGEE spectra, with the executable operations as nine tool servers built on the Model Context Protocol (MCP) and the operating decisions…

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astro-ph.HE2026年8月11日

Wind-confined jet collimation revealed by the acceleration-phase photosphere of GRB 220426A

Felix Ryde, Asaf Pe'er

We analyze the prompt emission of the exceptionally bright GRB 220426A observed by Fermi/GBM, whose time-resolved spectra are among the narrowest measured in any GRB. Here we show that observations during the first $\sim 5$s are consistent with the signal being emitted while the jet was still in the initial radiation-dominated acceleration phase. The time-resolved spectra allow the effective launch radius, $r_0$, to be inferred with unusual precision. We find $r_0 \sim \mathrm{few} \times 10^{10…

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astro-ph.GA2026年8月11日

ATLAS. III. Dust Around Little Red Dots: Hydrogen Line Ratios beyond Dust-free Non-Case B Models

Tomokazu Kiyota, Masami Ouchi, Hiroto Yanagisawa, Makoto Ando, Yuichi Harikane, Yuta Kageura, Minami Nakane, Yurina Nakazato et al.

We investigate broad hydrogen line ratios in little red dots (LRDs) using five high-redshift ($z>2$) sources from JWST/NIRSpec medium/high-resolution spectra in the DAWN JWST Archive and fifteen low-redshift sources ($z=0.1$--$0.9$) from the literature, all with broad H$β$ detected at $>5σ$. After carefully measuring the broad-line fluxes while accounting for absorption features and neighboring emission lines, we find that the broad H$α$/H$β$ ratios are very high, ranging from 6 to 30, well abov…

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astro-ph.SR2026年8月11日

Evidence for Solar-Cycle Modulation of the Alpha-to-Proton Temperature Ratio in Solar Wind

Aakash Gupta, Yogesh, Dibyendu Chakrabarty, Leon Ofman, Gregory G. Howes

The influence of collisional age $(A_c)$ on the alpha-to-proton temperature ratio $(T_α/T_p)$ has been explored in the past. However, the modulation of this ratio with respect to the solar cycle has remained unexplored so far. We show solar-cycle modulation of $T_α/T_p$ and $A_c$ using nearly three decades of in-situ observations from Wind spacecraft across distinct solar wind speed regimes and solar activity phases. Our results reveal that in the slow solar wind with velocity $ 1$, the ratio $T…

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gr-qcastro-ph.HEhep-ph2026年8月11日

Radiative Signatures from Warp Drives Traveling Through the Earth's Atmosphere

Shaun David Brocus Fell, Abraham Loeb

We investigate the observable signatures of zero ADM mass warp drive spacetimes traversing Earth's atmosphere. Numerical simulations indicate that an aircraft-scale spacetime bubble moving at relativistic velocities would have a pronounced observational signature, where interaction with the atmosphere can produce luminosities exceeding one terawatt. The signature of a spacetime bubble at rest or moving at low velocity relative to the Earth would not generate such extreme luminosities. These resu…

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astro-ph.IM2026年8月11日

Wavefront Profiling via correlation of GLAO open loop telemetry

Eden A. McEwen, Ryan Dungee, Mark Chun, Jessica R. Lu, Olivier Lai, Christoph Baranec

Adaptive Optics (AO) used in ground based observatories can be strengthened in both design and algorithms by a more detailed understanding of the atmosphere they seek to correct. Nowhere is this more true than on Maunakea, where a clearer profile of the atmosphere informs AO system development from the small separations of Extreme AO (ExAO) to the wide field Ground Layer AO (GLAO). Employing telemetry obtained from the 'imaka GLAO demonstrator on the University of Hawaii 2.2-meter telescope, we…

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astro-ph.SRastro-ph.EP2026年8月11日

Bernhard-1: An Eccentric Binary Periodically Obscured by its Misaligned Circumbinary Disk

Zhecheng Hu, Wei Zhu, Ping Chen, Richard Post, Weicheng Zang

Bernhard-1 is a proposed KH 15D-like circumbinary disk occultation (CBO) system, but its binary nature and disk geometry have not previously been confirmed. We present new optical and near-infrared spectroscopy together with multi-band photometric monitoring of the system. The radial velocities confirm that Bernhard-1 hosts a highly eccentric binary with $e = 0.80 \pm 0.09$, confirming that the periodic photometric variability arises from occultation by a misaligned circumbinary disk. Joint mode…

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astro-ph.IM2026年8月11日

Application of continuous corrections in widefield imaging obtained with the IDGCAL calibration method

Sebastiaan van der Tol

Image Domain Gridding (IDG) is an efficient method to evaluate A-projection, a method for correcting for direction dependent effects (DDEs) in radio astronomical imaging. The corrections i.e. the A-terms need to be estimated from the observed data through calibration. IDG-CAL is a calibration algorithm that employs the IDG algorithm in an iterative fashion to estimate A-terms directly. Initial results for low order A-terms are promising, however for deeper images higher order A-terms are needed.…

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astro-ph.SR2026年8月11日

Exploring the long-term temporal variability in polarization through multi-epoch optical spectro-polarimetry - Part II: A sample of symbiotic and red-giant stars

Arijit Maiti. Ruchi Pandey, Sube Singh Gurjar, Mudit K. Srivastava

Measuring polarization and its temporal variability in the continuum and across emission features provides a powerful probe of the small-scale circumstellar environments of astrophysical sources, on spatial scales otherwise inaccessible to direct imaging techniques. However, the photon-hungry nature of spectro-polarimetry has significantly limited the availability of such datasets in the literature. Here we present the results of a multi-epoch spectro-polarimetric survey of a sample of symbiotic…

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astro-ph.GAastro-ph.SR2026年8月11日

SIRIUS Project: Dynamical Evolution of Primordial Binaries during Star Cluster Formation

Naoto Harada, Michiko S. Fujii, Takayuki R. Saitoh, Yutaka Hirai

Binary populations are closely linked to the star formation process; however, their primordial properties can be changed by subsequent dynamical interactions within their natal clusters. The aim of this study is to clarify how different primordial binary populations affect the evolution of multiplicity and the global structure of forming star clusters. We investigate the dynamical evolution of primordial binaries during star cluster formation using self-consistent Nbody/smoothed particle hydrody…

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astro-ph.HE2026年8月11日

Synchrotron-Regulated Relativistic Magnetohydrodynamic Turbulence: Emission, Polarization, and Faraday Rotation

Xiaochen Sun, Luca Comisso Lorenzo Sironi, Anatoly Spitkovsky, Alexander Philippov

Relativistic magnetized plasmas in many high-energy astrophysical systems are both turbulent and strongly radiative, yet their nonlinear dynamics and radiative outcomes remain poorly understood. Here we present results from three-dimensional driven turbulence simulations in relativistic magnetohydrodynamics with synchrotron cooling. We compute Faraday rotation measures, synthetic synchrotron spectra and linear polarization maps from the simulated turbulence. The balance between energy injection…

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