研究動向

astro-ph.EP2026年8月26日

Assessing the Climate and Habitability of Tidally Locked Rocky Exoplanets

Erica Bisesi, Giuseppe Murante, Jost von Hardenberg, José A. Caballero, Michele Maris, Daniela Billi, Nicoletta La Rocca, Laura Silva et al.

Tidally locked exoplanets orbiting M dwarf stars are prime targets in the search for habitable worlds, yet their complex climate dynamics challenge conventional models of habitability. We homogeneously estimated the liquid-water habitability of exoplanets with the highest up-to-date Earth-similarity index. We modified the climate model PLASIM to apply it to tidally locked exoplanets across a range of parameters. We systematically classified and compared potentially habitable exoplanets and selec…

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nucl-thastro-ph.HE2026年8月26日

Impact of Nuclear Level Density on $r$-Process Rare-Earth Peak Nucleosynthesis

Hang Xu, Peng-Xiang Du, Jian Li, Dong-Liang Fang

The rare-earth peak ($A\sim164$) is a prominent feature of the $r$-process, and previous theoretical studies suggest that it is possibly linked to local nuclear structural effects. However, the nuclear level density (NLD), a physical quantity directly reflecting these properties, has been largely overlooked compared to other structural properties such as nuclear masses. To address this, we perform $r$-process simulations across three astrophysical scenarios using neutron-capture rates derived fr…

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astro-ph.SR2026年8月26日

Circular polarimetry of suspect wind-accreting pre-polars II

Pasi Hakala, Steven Parsons, Gavin Ramsay, Boris T. Gänsicke, Alex Brown

The origin of white dwarf magnetic fields is an open question. Furthermore, such fields play a vital role in the evolution of interacting binary stars. Here we present a study of white dwarf fields in so called pre-polars (or low accretion rate polars, LARPs , i.e. magnetic cataclysmic variables, where the mass losing secondary star is not in Roche lobe contact, but the systems experience accretion via stellar wind. Such systems play a crucial role in understanding the magnetic braking and the a…

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astro-ph.HE2026年8月26日

Is the mysterious {\it Punctum} a primordial black hole?

Man Ho Chan

A recent study has discovered a highly polarized millimeter continuum source called {\it Punctum} located at the central region of NGC 4945 which doesn't fit any known category. Apart from the radio detection at $\approx 100$ GHz, there is no identified counterpart to {\it Punctum} in other radio, infra-red, optical, and X-ray bands. All available potential models, including magnetar, supernova remnant and microquasar, cannot provide satisfactory explanation for the exceptionally high polarizati…

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physics.flu-dynastro-ph.EP2026年8月26日

Fluxes through a uniform double-diffusive staircase at low Prandtl number

Arstanbek Tulekeyev, Pascale Garaud

Double-diffusive convection in the diffusive regime is often observed to be in a long-lived layered state, well-known in the Arctic ocean and in volcanic lakes, and thought to exist in the interiors of giant planets. The density profile resembles a `staircase', with stacks of convective layers of uniform density separated by strongly stratified interfaces. The governing parameters are the Prandtl number $\mathrm{Pr}$, diffusivity ratio $τ$, density ratio $R_ρ$, and Rayleigh number $\mathrm{Ra}$.…

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astro-ph.SR2026年8月26日

Broadband 12-26 GHz Radio Radiation Reveals Evidence for Micro-flares on AU Mic

Isaiah I. Tristan, Rachel A. Osten, Yuta Notsu, Adina D. Feinstein, Adam F. Kowalski

We present sequential 12-18 and 18-26 GHz radio-band ($Ku$, $K$) VLA observations of the 22 Myr dM1e star AU Mic. We detect two flares and two marginal events over a total of 3 contiguous hours on source, resulting in a radio flare rate of $\sim$1 flare hour$^{-1}$. While this rate is consistent with previous $Ku$-band observations, both flaring ($<$1 mJy) and quiescent ($\sim$0.4 mJy) flux densities are significantly lower. Furthermore, the quiescent spectral shape here is distinct, allowing fo…

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astro-ph.SR2026年8月26日

Large fraction of blends from Rowan et al. (2023)

P Zasche

Following the work by Rowan et al., I found that a large fraction of systems presented as triple/quadruple stars are in fact only blends. After careful inspection of 225 candidate systems from Rowan et al., I found that one-third of them are, in fact, only blended signals of two different eclipsing binaries, well separated from each other on the sky. Their typical angular separation is dozens of arcsec, reaching up to more than 100 arcsec for some targets. This is probably due to relatively larg…

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astro-ph.GAastro-ph.IM2026年8月26日

Recovering the effective impact parameters in integral-field absorption-line tomography

J. A. Hernández-Guajardo, L. F. Barrientos, C. Ledoux, N. Tejos, E. J. Johnston, P. Anshul

Integral-field-unit (IFU) spectroscopy of extended background sources, such as gravitational arcs, delivers many closely spaced absorption sightlines through the circumgalactic medium (CGM) of foreground galaxies. However, the source extent and smearing through the point spread function (PSF) cause each spaxel to integrate light from a region larger than itself. The usually adopted geometric spaxel centre is therefore not representative of where the absorbed flux originates. Informed by high-res…

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astro-ph.GAastro-ph.EPgr-qc2026年8月26日

Laplace surface of eccentric orbits around Kerr black hole and black-hole effects on Lidov-Kozai cycles

Haonan Quan, Xing Wei

We study the Laplace surface of eccentric orbits around a Kerr black hole with a companion star. The two relativistic effects (periapsis apsidal precession and Lense-Thirring precession) balance companion's tidal effect. By solving the secular equations, we find that the two branches of equilibrium solutions exist only in a narrow range of orbital inclinations of test particle, and that the stability exists when companion's obliquity approaches 90 degree. We then study the black-hole effects on…

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astro-ph.GA2026年8月26日

A systematic study of AGN feedback in a disk galaxy using MACER. III. High Gas Fractions in AGN Hosts

Yuxuan Zou, Feng Yuan, Suoqing Ji, Jinyi Shangguan, Hassen M. Yesuf, Lu Shen, Luis C. Ho

We use high-resolution hydrodynamic simulations in the MACER framework to explain why low-redshift PG quasar hosts can retain substantial cold-gas reservoirs, with gas fractions and gas-to-stellar mass ratios showing little dependence on instantaneous AGN luminosity. This paper is the third in a series systematically studying AGN feedback in a disk galaxy subject to cosmological gas inflow. The simulations include multiphase gas, star formation, stellar feedback, and self-consistent radiative an…

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hep-phastro-ph.COastro-ph.HE2026年8月26日

Multi-messenger signal from QCD-Axion Ultracompact Minihalos

Dorian W. P. Amaral, Enrico D. Schiappacasse, Karla Tapia-Rebolledo

We explore the multimessenger signatures from ultracompact minihalos (UCMHs) seeded by stellar-mass primordial black holes (PBHs) and composed of QCD-axion dark matter. Using the secondary-infall framework, with relic-abundance and isocurvature conditions from a pre-inflationary Peccei-Quinn scenario, we numerically recover the characteristic halo profile and adopt a conservative constant-density core for the innermost region. We study the gravitational wave and electromagnetic signatures from n…

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astro-ph.HE2026年8月26日

Constraining gamma-ray burst viewing angles with Swift/XRT afterglow light curves

Cheng-Jie Sun, Shuang-Xi Yi, Lin Zhou, Yuan-Chuan Zou, Yu-Peng Yang, Si-Ji Xin, Yan-Kun Qu, Wen-Long Zhang et al.

Gamma-ray bursts (GRBs) are among the most energetic phenomena in the universe, and their afterglow light curves encode information about jet geometry and viewing angle. To constrain GRB viewing angles, we analyzed jet break features in Swift X-Ray Telescope afterglow light curves using two top-hat jet models: a simplified geometric model without high-latitude emission (model 1) and a comprehensive model including it (model 2). Both models were applied to a sample of 20 GRBs in an interstellar m…

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astro-ph.EP2026年8月26日

Centimeter-wave OH observations of comets 12P/Pons-Brooks and C/2023 A3 (Tsuchinshan-ATLAS) with FAST

Long-Fei Chen, Juncen Li, Zhen Wang, Jian-Yang Li, Wing-Huen Ip, Zhong-Yi Lin, Bin Yang, Chao-Wei Tsai et al.

We present centimeter-wave spectroscopic observations of the OH 18-cm lines in two bright comets, 12P/Pons-Brooks and C/2023 A3 (Tsuchinshan-ATLAS), conducted with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) during their 2024 apparitions. For the Halley-type comet 12P/Pons-Brooks, five epochs of OH observations were obtained. The main OH lines at 1665 and 1667 MHz were robustly detected in absorption during one pre-perihelion epoch, while upper limits were derived for two po…

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astro-ph.HE2026年8月26日

What is the reason for the lack of cool evolved stars near the center of the Galaxy?

Petr Kurfürst, Michal Zajaček, Norbert Werner, Jiří Krtička, Matúš Labaj

The observed deficit of bright late-type giants in the central parsec of the Milky Way remains an open problem. We investigate whether repeated passages of red giants (RGs) through a past jet from Sgr$~$A$^*$ can modify their envelopes and apparent spectral types. Three-dimensional hydrodynamical simulations follow a $1\,M_\odot$, $100\,R_\odot$ RG through up to ten jet crossings at $10^{-3}\,\text{pc}$, using jet kinetic luminosities of $10^{42}$, $10^{44}$, and $10^{48}\,\text{erg}\,\text{s}^{…

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astro-ph.EP2026年8月26日

Discovery and Characterization of the TOI-4468 Planetary System: A Transiting Hot Jupiter With a Lone Nearby Outer Companion

Joseph R. Livesey, Benjamin J. Hord, Juliette Becker, Andrew Vanderburg, Joseph E. Rodriguez, Elise Koo, Chelsea X. Huang, Gudmundur Stefánsson et al.

We report the discovery of two planets, a hot Jupiter and a nearby outer sub-Neptune, orbiting the star TOI-4468. This system is unique among the current exoplanet census in that it features a close outer companion to a hot Jupiter without an accompanying inner companion. By jointly fitting radial velocity measurements taken with the NEID spectrograph and transit photometry from TESS and several ground-based observatories, we constrain the orbital periods, masses, and radii of these two planets.…

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astro-ph.IMastro-ph.EP2026年8月26日

Spatially Scanned STIS Spectra of the Exoplanet Host Star 55 Cnc

D. E. Welty, J. D. Lothringer, D. K. Sing, A. M. Jones, A. Riley, C. R. Proffitt

We discuss the analysis of two sets of optical/near-IR spectra of the exoplanet host star 55 Cnc, obtained with the Space Telescope Imaging Spectrograph (STIS) and grating G750L in spatial scanning mode, in order to assess the performance of that relatively new observing mode for studies of transiting exoplanets. Standard pipeline reductions of the CCD spectral images were augmented by custom procedures for removing both cosmic rays and the strong fringing seen at wavelengths longer than 7000 A.…

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astro-ph.IM2026年8月26日

Deep Learning-Based Coarse Alignment and Cophasing of a Distributed-Aperture Telescope. Application to the Small ExoLife Finder (SELF)

N. Arteaga-Marrero, J. Iborra-Luis, A. Padrón-Brito, J. Kuhn

The ExoLife Finder (ELF), a 35--50-meter-class Fizeau interferometric telescope, was designed to detect biosignatures on exoplanets through direct imaging. The Small ExoLife Finder (SELF), a 3.5-meter prototype, serves as a testbed for the innovative technologies required for such a facility. A key challenge is the precise cophasing of its distributed aperture, where the optical path differences between subapertures must remain below a small fraction of the operating wavelength. This work invest…

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astro-ph.SRastro-ph.GAastro-ph.IM2026年8月26日

ABYSS. IV. Identifying signatures of stellar youth in APOGEE spectra

Valentina Bonilla Villalobos, Marina Kounkel, Joseph Mullen, Eleonora Zari, Alexandre Roman-Lopes, Keivan Stassun, Ricardo López-Valdivia, Jinyoung S. Kim et al.

We develop a convolutional neural network classifier that performs spectroscopic identification of stellar youth (<40 Myr) in APOGEE spectra. This classifier is sensitive to several youth-related features, including rotational broadening, which is common in younger stars, and to several discrete lines that appear to be indicative of a very spotted photosphere. The model is successful at identifying youth across a wide range of stars, achieving its strongest performance at discriminating young M…

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astro-ph.IMphysics.space-ph2026年8月26日

Capra: Scalable HEALPix-Native Intensity Reconstruction for High-Resolution IMAP Analyses

Nikola Bukowiecka, Daniel B. Reisenfeld, Maciej Bzowski

We present Capra, a HEALPix-native pipeline for reconstructing all-sky energetic neutral atom (ENA) intensity maps from the NASA Interstellar Boundary Explorer (IBEX) and Interstellar Mapping and Acceleration (IMAP) missions' event-counting data. Capra produces two products: (1) a baseline boresight-assigned map, and (2) an optional smoothed map on the HEALPix grid. This produces smooth, physically interpretable maps with consistent resolution changes and reference-frame transformations. The smo…

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astro-ph.IMastro-ph.SR2026年8月26日

TESSExtractor: A web-based interactive tool for light-curve visualisation and period estimation using TESS full-frame images

Javier Serna, Jesús Hernández, Sean P. Matt, Giovanni Pinzón, Astaroth Elizabethson, Jorge Martínez-Palomera, Carlos G. Román-Zúñiga, Sergio Sánchez-Sanjuán et al.

We present a user-friendly web application that allows users to extract, visualise, and interact with TESS light-curves (LCs) from full-frame images. The service works for any star identified in the TIC database or using stellar coordinates. TESSExtractor performs photometry using a circular aperture centred on the object of interest, with a sky annulus for background subtraction. The application also uses cotrending basis vectors provided by TESS to correct photometry for possible systematic ef…

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astro-ph.IM2026年8月26日

CCAT: The Prime-Cam Instrument for the Fred Young Submillimeter Telescope -- Overview and Status

Eve M. Vavagiakis, Yuhan Wang, Lawrence T. Lin, Manuel Aravena, Jason E. Austermann, Frank Bertoldi, James Burgoyne, Victoria Butler et al.

Prime-Cam is a first-generation science instrument for the CCAT Observatory's six-meter aperture Fred Young Submillimeter Telescope (FYST), under construction at an elevation of 5600 m on Cerro Chajnantor in Chile's Atacama Desert. Prime-Cam will deliver over ten times greater mapping speed at submillimeter wavelengths than current facilities for unprecedented broadband and spectroscopic measurements in windows between 1.4 -- 0.3 mm (220 -- 850 GHz). When fully populated, Prime-Cam will field ov…

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astro-ph.IMphysics.space-ph2026年8月26日

A Singular Value Decomposition Framework for Jovian Radio Emissions from Parker Solar Probe

Evan Wille, Zack Li, Marc Pulupa, Leon V. E. Koopmans, Philippe Zarka, Stuart Bale

Jovian decametric and hectometric radio emissions provide critical insights into Jupiter's magnetospheric dynamics and its electrodynamic coupling with Io. Across 21 perihelion encounters since its first light in 2018, the Parker Solar Probe mission has repeatedly recorded high-resolution radio and plasma wave data near closest approach, as a result serving as a long-term distant observer of the Jovian system. However, extracting these relatively faint planetary signals from the continuous solar…

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astro-ph.GAastro-ph.CO2026年8月26日

Tracing Galaxy Bias Through the Cosmic Web: The Role of Filaments

Constanza A. Soto-Suárez, Antonio D. Montero-Dorta, Daniela Galárraga-Espinosa, Ignacio G. Alfaro, Andrés Balaguera-Antolínez, Ravi K. Sheth, Pablo López

The large-scale clustering of galaxies depends not only on their internal properties but also on their location within the cosmic web, which defines the anisotropic environments where galaxies form and evolve. Filaments serve as bridges through which galaxies and dark matter flow from low-density regions toward the highest-density nodes. In this work, we aim to map galaxy bias, which quantifies how these tracers follow the underlying dark matter density field, through the cosmic web, with a spec…

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astro-ph.IM2026年8月26日

Study of Vibrations at SOAR

Andrei Tokovinin

The 4.1-m Southern Astrophysics Research (SOAR) telescope in Chile resembles larger optical telescopes by its thin actively controlled primary mirror, built-in tip-tilt correction, lightweight structure, and adaptive optics (AO) turbulence correction. The non-stationary vibration of the SOAR optical axis with a frequency of 50 Hz and an amplitude reaching 20-30 mas has been detected by the AO system, degrading the quality of optical speckle interferometric data. Accelerometers revealed that the…

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astro-ph.GA2026年8月26日

To be lensed or not to be lensed: on the nature of the alleged high-z lensed quasars J0109-5424 and P170+20

Aurora Mata-Sanchez, Emanuele P. Farina, Anniek J. Gloudemans, Debora Pelliccia, Roberto Decarli, Eduardo Banados, Silvia Belladitta, Manuela Bischetti et al.

We present a detailed multi-wavelength analysis of two gravitationally lensed z>6 quasar candidates: J0109-5424 and P170+20. Using JWST/NIRSpec near-infrared data from the Aether survey, we demonstrate that J0109-5424 is in fact a FeLoBAL quasar at z=2.07, exhibiting strong iron broad absorption lines that mimic the Lyman break. From the Pabeta emission line, we estimate a black hole mass of 3.9 x 10^8 Msun and a bolometric luminosity of Lbol = 7.7 x 10^45 erg/s for this quasar. Follow-up HST/AC…

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astro-ph.EP2026年8月26日

Tidal Demise: The Evolution and Fate of a Hypothetical Venus Moon

Stephen R. Kane, Franck Selsis, Jeremy Leconte, Sean N. Raymond

Venus possesses no natural satellite, raising the question whether a formed moon could have survived. We explore the tidal evolution of a Venus-moon system, coupling Venus's spin to the satellite's orbit under tides from the moon and Sun. We survey spin period ($P_0 = 5$--100~hr), moon mass ($M_m = 0.01$--$10~M_{\rm Moon}$), eccentricity, quality factor, and initial semi-major axis under both constant-$Q$ and constant time lag models. Survival depends on competition between outward migration ($\…

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astro-ph.EP2026年8月26日

Kepler-50: Two Planets in Close Resonance Perturbed by a Non-transiting Planet

Daniel Jontof-Hutter, Jason F. Rowe, Jack J. Lissauer, Daniel C. Fabrycky

Kepler-50 has two transiting planets close to the 6:5 commensurability. We analyze transit times measured from Kepler data with dynamical fits. We attribute the residual signal to a near-resonance non-transiting third planet in the system. The parameters of the third planet are degenerate. We identified 55 (15) regions of interest for an exterior (interior) perturber, and characterize system parameters in each region of interest with posterior sampling. We find that removing samples that are not…

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astro-ph.SR2026年8月26日

A Seismic Technique for Obtaining White Dwarf Fundamental Parameters from Mean Period Spacings and Astrometry

Keaton J. Bell, Agnès Bischoff-Kim

We present a new statistical technique that utilizes the synergy of precision astrometry and time series photometry from modern space missions to obtain reliable physical parameters of pulsating white dwarf stars. We compute a grid of white dwarf structural models that span the helium-atmosphere pulsating white dwarf (DBV) instability strip, showing that mean period spacings between adjacent pulsation modes and absolute magnitudes derived from Gaia astrometry vary monotonically and in opposing d…

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astro-ph.GAastro-ph.HE2026年8月26日

The ionizing properties of JWST's compact broad-line emitters

Sara Mascia, Jorryt Matthee, Alberto Torralba, Jenny E. Greene, Anna-Christina Eilers, Edoardo Iani, Rohan P. Naidu

The recent JWST discovery of a numerous population of broad-line emitters (BLEs) at $z>4$ has reopened the question of whether sources other than faint galaxies contributed significantly to cosmic reionization. To assess this contribution, we present a systematic census of compact, blue broad-line emitters at $4\leq z\leq7$ selected from the DJA, designed to isolate sources in which the UV continuum and the broad-line emission originate from the same compact physical region. Starting from a pare…

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astro-ph.SRastro-ph.GAastro-ph.IMcs.LG2026年8月26日

EncoTESS: Age-Sensitive Encodings from Raw TESS Light Curves

Phil R. Van-Lane, Joshua S. Speagle, Ryan Cloutier, Christopher A. Theissen, Gwendolyn M. Eadie, Ilay Kamai

Main sequence stars of spectral types late F through M exhibit systematic variability in photometric light curves, particularly when they are young. Rotational modulation of starspots manifests as quasi-sinusoidal variability, which enables the measurement of rotation periods. Variability can also be stochastic, as in stellar flaring. However, since measurements of stochastic processes depend on the time of observation, they are typically noisier. Considering that different manifestations of var…

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