研究動向

astro-ph.HE2026年8月21日

Effects of Ambient Medium Profiles on the Evolution of Relativistic Magnetized Jets

Xufan Hu, Yosuke Mizuno

Relativistic radio-galaxy jets are conventionally divided into two morphological classes: FR~I and FR~II. Among them, FR~I jets have relatively low radio luminosities and edge-darkened morphologies, indicating they undergo substantial deceleration and disruption on sub-kiloparsec to kiloparsec scales, often developing a turbulent and plume-like morphology. Here, we investigate the evolution of relativistic magnetized jets in stratified ambient media using 2D and 3D relativistic magnetohydrodynam…

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astro-ph.EPastro-ph.IM2026年8月21日

Microwave Remote Sensing of Giant Planet Atmospheres: Considerations for Saturn and Uranus Orbiter Missions

Alex Akins, Mark Hofstadter

Microwave radiometer instruments are uniquely capable of studying volatile element abundances and heat/mass transport within the deep atmospheres of giant planets. The results of the Juno MWR experiment have challenged long-held assumptions regarding Jupiter's troposphere, and the inclusion of such an instrument on future missions to Saturn or the ice giants would similarly re-write our understanding of giant planet atmospheres. We present a high-level summary of the capabilities of microwave ra…

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astro-ph.IMastro-ph.GAcs.AIcs.LG2026年8月21日

Amplifying the imaging power of digital sky surveys with space telescopes data and generative AI

Sai Teja Erukude, Lior Shamir

While Digital sky surveys provide excellent throughput of image data and can cover a large footprint, their imaging power is normally inferior to that of space-based telescopes. Space-based telescopes, on the other hand, provide excellent imaging power and can image the deep Universe, but cannot provide the same throughput as advanced ground-based sky surveys. Here, we utilize generative AI to elevate the quality of galaxy images taken by ground-based telescopes to the level of details enabled b…

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astro-ph.EPastro-ph.IMeess.SYmath.OC2026年8月21日

Physics-Informed Bayesian Optimization Warm-Starts for Sequential Convex Programming in Asteroid Surface Hopping

Baran Ekşi, Tufan Kumbasar

Surface hopping is an attractive mobility mode for small-body exploration, but designing fuel-optimal hops on asteroid 433~Eros requires solving a nonconvex optimal control problem with an irregular polyhedral gravity field, thrust--mass coupling, and collision-avoidance constraints. We show that a physics-informed Bayesian Optimization (BO) warm-start---a Gaussian-process search over a single Bézier control point that requires no offline training---provides a more reliable initialization for Se…

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astro-ph.EP2026年8月21日

Accounting for Transit Timing Detectability: Biases in Planetary Radius and Orbital Period

Skylar D'Angiolillo, Daniel Fabrycky, Mariah G. MacDonald

Transit Timing Variations (TTVs) are deviations from the time an observer would expect to see an exoplanet transit its host star. In multi-planetary systems, significant TTVs may indicate the presence of another body in the system gravitationally interacting with the transiting exoplanet. T. Holczer et al. (2016) catalogs 2599 Kepler Objects of Interest (KOIs) and provides a statistical analysis of their TTVs for candidates that have transited at least seven times. However, this conservative lim…

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gr-qcastro-ph.IM2026年8月21日

Bayesian P-spline recovery of stochastic gravitational-wave backgrounds in LISA

Nazeela Aimen, Patricio Maturana-Russel, Avi Vajpeyi, Nelson Christensen, Renate Meyer

The detection of a stochastic gravitational-wave background (SGWB) is a primary science objective for the Laser Interferometer Space Antenna (LISA). However, extracting these signals is difficult because both the signal and the instrumental noise are stochastic and overlapping in the millihertz band. In this work, we present a Bayesian framework for the joint estimation of LISA noise and SGWB signals. Our approach models the LISA instrumental noise using flexible log-penalized splines, employing…

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astro-ph.SR2026年8月21日

Statistical Analysis of Minifilament Eruptions Using Full-disk H$α$ Blue-wing Observations at Big Bear Solar Observatory

Artin Khaleghi, Qin Li, Nengyi Huang, Jeongwoo Lee, Haimin Wang

This paper presents a comprehensive statistical analysis of minifilament eruptions (MFEs) using high-cadence full-disk H$α$ blue-wing observations from Big Bear Solar Observatory. Despite the recognized importance of MFEs for coronal dynamics and solar wind structuring, previous efforts were often limited by small sample sizes or restricted fields of view, leaving open questions about their global occurrence and characteristic properties. We developed an algorithm incorporating intensity thresho…

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astro-ph.GA2026年8月21日

Mapping the z>=5 SiIV Column Density Distribution onto the Galaxy Stellar Mass Function Using the Cumulative Absorption Cross Section

Kristian Finlator, Sam Patterson, Nora Nava, Ayanah Cason, Samir Kušmić, Ezra Huscher, Farhanul Hasan

Efforts to constrain directly the activity in low-mass galaxies confront sensitivity limits even in the JWST era. Metal absorbers offer a complementary probe and are easier to detect, but leveraging them requires a known relationship between absorber strength and host mass. To this end, many studies assume a simple monotonic relationship between absorber strength and host mass. This ansatz ignores evidence that galaxies at fixed luminosity host absorbers spanning a variety of strengths. We addre…

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cs.PLastro-ph.IMastro-ph.SRcs.CEcs.DC2026年8月21日

Portability of Fortran's 'do concurrent' on GPUs II

Ronald M. Caplan, Miko M. Stulajter, Jon A. Linker, Jeff Larkin, Nikolaos Tselepidis, Harald Servat, Shiquan Su, Giacomo Capodaglio et al.

There continues to be growing interest in using standard language constructs for parallel and accelerated HPC computing, avoiding the need for (sometimes vendor-specific) external APIs. For Fortran applications, language features such as 'do concurrent' loops open the door for compilers to implement multi-threaded, GPU-accelerated, and even distributed multi-node code with only the standard language. Here, we explore the current status of using 'do concurrent' for GPU-accelerated Fortran applica…

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astro-ph.EP2026年8月21日

JWST Spatial-Spectral Mapping of Green Comet C/2022 E3 (ZTF)

Stefanie N. Milam, Nathan X. Roth, Geronimo L. Villanueva, Dominique Bockelee-Morvan, Jacques Crovisier, David E. Harker, Michael S. P. Kelley, Kiernan D. Foster et al.

We report a survey of molecular emission from cometary volatiles using the James Webb Space Telescope (JWST) toward Oort cloud comet C/2022 E3 (ZTF) carried out on UT 2023 February 28 and March 1 at a heliocentric distance (rH) of 1.33 au. These measurements of H2O, HCN, CH3OH, C2H6, CH4, CO, CO2, 13CO2, and OCS sampled post-perihelion molecular chemistry in C/2022 E3. A suite of near to mid-infrared OH (prompt emission) transitions were also detected. This work presents nucleus-centered spectra…

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astro-ph.EP2026年8月21日

Effects of Outer Giant Planets on In Situ Formation of Inner Super-Earths

Phoebe Sandhaus, Rebekah I. Dawson, Mariah G. MacDonald, Cody J. Shakespeare, Sarah Morrison

Recent studies have found an observational correlation between the presence of outer giant planets and inner super-Earths, which implies that outer giants do not suppress the formation of super-Earths. We simulate late-stage in situ planet formation in the presence of outer giant planets using $N$-body simulations. We investigate the effects of two sets of outer giants: the four Solar System giant planets and three dynamically active giant planets. Compared to systems without outer giants, we fi…

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astro-ph.HEastro-ph.SR2026年8月21日

AT 2016blu: Accretion-Powered Outbursts in a Luminous Blue Variable and Compact Object Binary

Mojgan Aghakhanloo, Núria Torres-Albà, Nathan Smith, Raphael Baer-Way, Shazrene Mohamed, Alexei V. Filippenko, WeiKang Zheng, Thomas G. Brink et al.

We present the first X-ray detection of the supernova (SN) impostor AT 2016blu in NGC 4559. AT 2016blu exhibited 27 detected quasiperiodic (~113 day) outbursts between 2012 and June 2026, presumably triggered by periastron passages in an eccentric binary system in which the primary is a $\gtrsim 33~M_{\odot}$ luminous blue variable (LBV). AT 2016blu was serendipitously observed by Chandra in 2001-2002, prior to its first documented outburst in 2012, but the stacked archival data show no X-ray de…

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astro-ph.HE2026年8月21日

Investigating the Multiwavelength Emission of Binary SMBH Candidate SDSS J095036.75+512838.1

Cassandra Daniele, Adi Foord, Jessie Runnoe, Michael Eracleous, Niana N. Mohammed

We present results from a multiwavelength study of the binary AGN candidate SDSS J095036.75+512838.1, which was identified as a candidate binary SMBH system due to its significant and variable broad H$β$ line shifts. We use available infrared-to-X-ray data to investigate the system's accretion properties. Analyzing recent Chandra observations, we characterize the X-ray emission and test the binary SMBH hypothesis. We find that the X-ray spectrum is well-modeled as a single AGN, with a 2--10 keV…

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nucl-thastro-ph.HEgr-qc2026年8月21日

Trace Anomaly and Effective Topological Sources in Neutron Stars

Federico Nola

This work investigates whether the trace anomaly can diagnose the stellar response to a topological scalar field in tensor multi-scalar gravity. Eleven cold tabulated equations of state (EoSs) were examined, with six retained after general relativistic (GR) thermodynamic and causality checks. Their fiducial topological configurations were compared with the corresponding GR models under complementary matching prescriptions. After controlling for stellar mass and EoS dependence, the GR trace sourc…

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astro-ph.IMastro-ph.EP2026年8月21日

High-contrast aperture masking interferometry: detecting companions within the diffraction limit

Benjamin Calvin, Michael Fitzgerald, Jessica Castellanos

The pursuit of the direct discovery and characterization of Earth-like exoplanets has motivated high contrast imaging surveys using coronagraphs with narrow inner working angles. Traditional imaging methods, however, are limited by the size of the on-axis PSF and typically only detect companions at angular separations of > 2$λ$/D. Meanwhile, non-redundant masking (NRM) techniques have been used with single-aperture telescopes to interferometrically resolve astrophysical features at angular scale…

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astro-ph.COastro-ph.GA2026年8月21日

On what scales does strong lensing robustly constrain the mass profile of low-mass perturbers?

Maryam Tajalli, Simona Vegetti

Galaxy-galaxy strong gravitational lensing is an established method to detect and characterise low-mass haloes, which are otherwise too faint to be directly observed. Recent analyses have shown empirically that there exists a characteristic radius within which the projected enclosed mass of these haloes can be robustly measured. Here we provide a physically and mathematically motivated definition of this robust radius based on the Fisher information matrix. We show that for any spherically symme…

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astro-ph.EPastro-ph.IMastro-ph.SR2026年8月21日

Leveraging Impact Parameter to Mitigate the Transit Light Source Effect: Early Insights from TRAPPIST-1

Ana Glidden, Alexander I. Shapiro, Sara Seager, Nadiia Kostogryz, Valeriy Vasilyev, Roeland P. van der Marel, Julien de Wit, Benjamin V. Rackham et al.

Stellar activity complicates exoplanet transmission spectra, particularly for smaller planets around M dwarfs with JWST. The transit light source (TLS) effect, the imprinting of spectral differences between the average stellar disk and the occulted transit chord onto the transmission spectrum, makes it challenging to directly use the out-of-transit spectrum to correct for stellar contamination. Theory and observations suggest that spots may concentrate towards higher latitudes when the Coriolis…

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astro-ph.GA2026年8月21日

An Optical Illusion: High Electron Densities Create Extremely Metal-Poor Galaxy Impostors

Tiger Yu-Yang Hsiao, Danielle A. Berg, Steven L. Finkelstein, Ansh R. Gupta, Zorayda Martinez, Anthony J. Taylor, Hollis B. Akins, Oscar A. Chavez Ortiz et al.

JWST has enabled the discovery of dozens of extremely metal-poor galaxies (EMPGs) with metallicities below $5\%\,Z_{\odot}$, representing a significant leap toward detecting the first galaxies without metals. However, accurate metallicity measurements require careful determination of physical conditions in the ionized gas. In this paper, we study four galaxies that appear to be EMPGs when analyzed using the direct $T_e$ method with the common low-density assumption ($n_e=10^3\,{\rm cm}^{-3}$). T…

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astro-ph.GA2026年8月21日

The Nearby Star Formation and Supernova Histories Reconstructed from Young Star Clusters

Cameren Swiggum, Catherine Zucker, Michelangelo Pantaleoni González, Emily L. Hunt, Robert A. Benjamin, Sebastian Hutschenreuter, Alena K. Rottensteiner, Efrem Maconi et al.

We reconstruct the recent star formation and core-collapse supernova (ccSN) histories of the Solar Neighborhood from the past trajectories of young star clusters. Using a \textit{Gaia}-based cluster sample with newly derived ages, masses, and bulk 3D velocities, we integrate orbits backward in an assumed axisymmetric Galactic potential and combine the trajectories with IMF sampling and stellar lifetimes to infer ccSN times and locations over the past 50 Myr. The result is an all-sky, 3D, time-re…

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astro-ph.HEgr-qc2026年8月21日

Probabilistic kilonova prediction from gravitational wave inferred binary neutron star parameters

Xiao-Fei Dong, Ik Siong Heng, Gavin P. Lamb, Chris Messenger, Nikhil Sarin, Benjamin Rayson, Nial R. Tanvir, Jessica Irwin et al.

Kilonovae provide a key electromagnetic window into binary neutron star mergers, revealing the properties of the merging system while probing r-process nucleosynthesis of the Universe. However, only a few kilonova candidates have been detected to date, with AT2017gfo being the only one associated with a gravitational wave event, GW170817. In this work, we present \textsc{Genova}, a probabilistic framework for predicting kilonova spectra and light curves directly from gravitational wave posterior…

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astro-ph.GA2026年8月21日

Re-evaluating the resolved mass-metallicity relation with a self-consistent metallicity calibration

Ziming Peng, Renbin Yan, Zesen Lin, Xihan Ji

Aims. The mass-metallicity relation (MZR) is essential for understanding the chemical evolution of galaxies. Whether the star formation rate (SFR) plays a role in setting the metallicity has long been debated. Using various metallicity calibrations can result in different conclusions for this fundamental yet unresolved issue. Methods. We apply a self-consistent metallicity calibration based on photoionization models to re-evaluate the resolved and integrated MZR. We utilize the integral field un…

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astro-ph.GAastro-ph.SR2026年8月21日

ALOHA IRDCs Molecular Line Follow-up: I. Gas properties and kinematics

Jinjin Xie, Yaoting Yan, Zhiyuan Ren, Jarken Esimbek, Di Li, Yan Duan, Gary A. Fuller, Nicolas Peretto et al.

Infrared Dark Clouds are ideal sites for investigating the initial conditions of massive star and cluster formation. The A Lei Of the Habitat and Assembly of Infrared Dark Clouds (ALOHA IRDCs), a James Clerk Maxwell Telescope (JCMT) Large Program, has mapped nearby IRDCs with SCUBA-2. Complementary molecular line observations are needed to characterise the physical, kinematic, and chemical properties of the dense gas. We aim to determine the thermal, kinematic, and chemical properties of clumps…

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astro-ph.IMastro-ph.CO2026年8月21日

The SPT-3G+ receiver design

H. Athreya, Z. Ahmed, J. E. Austermann, K. Bae, A. Bapat, D. R. Barron, P. S. Barry, A. N. Bender et al.

We present the thermo-mechanical design of the cryostat and camera optics for SPT-3G+, a new receiver being developed for the South Pole Telescope (SPT). The receiver consists of 14 detector arrays of 90/150 GHz dichroic polarization-sensitive pixels, totaling 24,080 transition-edge sensor detectors. Each detector array lies at the end of an optics tube, each approximately 240 mm in diameter and 772 mm in length, which are arranged in a hexagonal close-packed configuration to achieve a 4 degree…

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gr-qcastro-ph.IMcs.LG2026年8月21日

Gravitational-wave parameter estimation with machine-learning generated surrogate waveforms

Suyog Garg, Kipp Cannon

The worldwide network of gravitational-wave detectors have detected more than 350 binary coalescence events till date. Future third-generation detectors, like Einstein telescope, are expected to detect orders-of-magnitude more signals from sources with more complicated characteristics, including eccentric orbits and high-mass ratio binaries. It is well-established that the computational cost of parameter estimation for signals from these kinds of sources will be extremely high. In particular, th…

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astro-ph.SR2026年8月20日

Toward Operational Solar Flare Peak Flux Nowcasting: A Strategy Combining Real-Time Data, Machine Learning, and NOAA Flare Detection Criteria

Kangwoo Yi, Qin Li, Haodi Jiang, Meiqi Wang, Haimin Wang, Bo Shen

We present the RMN strategy (Real-time data, machine learning, and NOAA flare detection criteria) for nowcasting the peak soft X-ray flux of ongoing solar flares under operationally realistic conditions. The strategy combines real-time GOES 0.1-0.8 nm X-ray observations with an attention-based sequence-to-sequence Long Short-Term Memory model. Under the NOAA flare detection criteria, predictions are evaluated at one-minute intervals from three minutes after the cataloged onset to the observed pe…

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astro-ph.SR2026年8月20日

Chromospheric heating and magnetic topology above the shared penumbra of a delta-spot: Multi-line inversions and multi-height magnetic-field extrapolations

M. Kriginsky, J. Leenaarts, J. de la Cruz Rodríguez, A. Pastor Yabar

We analysed observations of the Fe I 617.3 nm, Ca II 854.2 nm, and Ca II H lines obtained with CRISP and CHROMIS at the SST. Spatially coupled non-LTE inversions constrained the chromospheric atmosphere, while the WFA provided estimates of the chromospheric line-of-sight magnetic field. We combined these photospheric and chromospheric constraints with an HMI magnetogram as input to a multi-height field extrapolation. We characterised the reconstructed topology using the twist number, squashing f…

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gr-qcastro-ph.HEhep-ph2026年8月20日

Universal Relations for Neutron Stars from Asymptotic Analysis

Syo Kamata, Josuke Minamiguchi, Shuhei Minato

Dimensionless observables of neutron stars, such as the moment of inertia, the tidal deformability, the spin-induced quadrupole moment, and the compactness, satisfy the I--Love--Q and Love--$C$ universal relations to percent-level accuracy over a wide range of equations of state. We investigate analytically the origin of this insensitivity in the stellar structure equations. We derive asymptotic expansions of these relations directly from the differential equations and boundary conditions for sl…

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astro-ph.SRastro-ph.GAastro-ph.HE2026年8月20日

SN 2021pfs: A Type Ia Supernova Likely Affected by Progenitor Metallicity, as Revealed by Comparison with Its Twin Counterpart

Abdusamatjan Iskandar, Xiaofeng Wang, Ali Esamdin, Wenxiong Li, Xiangyun Zeng, Ruifeng Huang, Guoliang Lu, D. Andrew Howell et al.

We present extensive photometric and spectroscopic observations of the normal type Ia supernovae (SNe Ia) 2021pfs, which occurred in the Seyfert 2 galaxy NGC 5427 at a redshift 0.009. SN 2021pfs reached an absolute \textit{B}-band peak magnitude of $M_{\rm max}(B)=$-19.28 $\pm$ 0.40 mag. The mag and a post-peak decline rate of $Δm_{15}(B)=$1.13 $\pm$ 0.06 mag. The observed properties of this nearby SN Ia closely resemble those of SN 2011fe, including the main optical spectroscopic features and p…

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astro-ph.HE2026年8月20日

J0011+3443: a GPS compact symmetric object, gravitational lens, or dual AGN?

Efthalia Traianou, Tingting Liu, Roman Gold, Richard Mushotzky

We present new multi-frequency VLBA observations of \object{J0011+3443} (TXS\,0008+344, $z=0.89$) at 2.3, 4.9, 8.5, and, for the first time, 23.6\,GHz. The source consists of two compact components A and B at a projected separation of $314\pm2$\,pc, plus a third feature C detected at 23.6\,GHz at $0.6$\,mas from A. Archival low-resolution radio measurements confirm an integrated gigahertz-peaked spectrum, with an observed-frame peak frequency of $ν_\mathrm{peak}=0.73\pm0.08$\,GHz and a peak flux…

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physics.plasm-phastro-ph.EPphysics.space-ph2026年8月20日

Effect of ion temperature on lunar photoelectron sheath

Trinesh Sana, Sanjay K. Mishra

Observations suggest that the solar wind ions impinging on the lunar surface possess a finite temperature. The effect of ion temperature on the plasma sheath over the lunar surface is investigated in this paper. To account for thermal effects, a thermal pressure term has been added to the ion-flow force equation. Quantitative estimation of sheath characteristics has been performed by solving the Poisson equation, accounting for photoelectrons, solar wind electrons, and warm ions. Notably, the pr…

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