研究動向

astro-ph.GAastro-ph.COastro-ph.HEastro-ph.IM2026年9月20日

Surveying the Universe in 4D: Beating Cosmic Variance with Wide-Field Slitless Spectroscopy from HST, JWST, Euclid, Roman, and Beyond

Andreea Petric, Gaël Noirot, Stacey Alberts, Russell Ryan, Louis-Gregory Strolger, Vicente Estrada-Carpenter, Mainak Singha, Adrian E. Bayer et al.

We summarize strategies, lessons learned, and future directions from the Space Telescope Science Institute workshop Surveying the Universe in 4D: Beating Cosmic Variance with Wide-Field Slitless Spectroscopy from HST, JWST, Euclid, Roman, and Beyond, held August 24--28, 2026. The workshop examined scientific results, observational and data analysis challenges, extraction tools, and future opportunities. Discussions highlighted (1) the transformative potential of WFSS for the study of transient p…

詳細を見る →

astro-ph.GA2026年9月20日

Star formation and morphological trends in the Antlia cluster: Probing environmental influence out to 5R200

Ciria Lima-Dias, Antonela Monachesi, Gissel P. Montaguth, Rodrigo F. Haack, Daniela E. Olave-Rojas, Hugo Méndez-Hernández, Sergio Torres-Flores, Luis Otárola et al.

Galaxy evolution in dense environments such as clusters is strongly affected by environmental processes that can alter both morphology and star formation activity. We investigate these effects in the Antlia cluster out to 5R200 using Southern Photometric Local Universe Survey (S-PLUS) data. We derive H-alpha-based star formation rates from the J0660 band and Sersic indices with GALFITM. Our analysis focuses on 154 spectroscopically confirmed galaxies brighter than mr = 16. We classify galaxies a…

詳細を見る →

astro-ph.EP2026年9月20日

Searching for Embedded Protoplanets with the Keck/NIRC2 Vortex Coronagraph: Confirmation of a Core-accretion Planet in the Narrow Gap of the Elias 2-24 Disk

Andrea Bernardi, Alice Zurlo, Lucas A. Cieza, Garreth Ruane, Valentin Christiaens, Anuroop Dasgupta, Greta Guidi, Dimitri Mawet et al.

We present high-contrast imaging observations of seven stars obtained with the Keck/NIRC2 vortex coronagraph between 2018 May and June in the $L'$ and $M_s$ bands. All targets host protoplanetary disks with substructures such as gaps and cavities, potentially tracing ongoing planet formation. Our aim is to assess whether these embedded planets can be directly detected. We reduced the observations with a custom pipeline based on the VIP Python package. Postprocessed images were obtained using ang…

詳細を見る →

astro-ph.EPphysics.geo-ph2026年9月20日

Super-Earth Interiors Shrink by About 10% as They Crystallise

Tim Lichtenberg, Mara Attia, Harrison Nicholls, Mariana Sastre, Dan J. Bower, Karen Stuitje, Flavia C. Pascal, Laurent Soucasse et al.

Super-Earth exoplanets are among the most abundant planets known, yet their bulk densities leave the interior state degenerate. The static structure models used to interpret them, and the interior retrievals built on them, typically describe the cold, solidified end state of an evolution that begins hot and molten. During this magma ocean stage the interior, the outgassed atmosphere, and the surface co-evolve and set the long-term climate and geophysics of super-Earths. We develop and validate a…

詳細を見る →

astro-ph.GA2026年9月19日

Sulfur-bearing molecules in a sample of active star-forming cores

R. D. Taboada, N. C. Martinez, S. Paron, A. Petriella, M. E. Ortega, L. Supán

Astrochemical processes involving sulfur are not yet well understood because cosmic sulfur reservoirs and the production pathways of sulfur-bearing species remain elusive. Addressing this, requires high-resolution interferometric observations capable of probing individual molecular cores. Following our previous study focused on early molecular cores, we are motivated to expand this investigation toward a sample of evolved cores to understand their chemical transition. We analyzed data from ALMA…

詳細を見る →

gr-qcastro-ph.HE2026年9月19日

Energy-momentum-squared gravity: charged quark star solutions with unified interacting matter

Ayan Banerjee, Bobur Turimov, Javlon Rayimbaev, Faisal Javed, Gulnoza Palvanova, Sulton Usanov

We investigate the equilibrium structure of electrically charged quark stars within the framework of energy-momentum-squared gravity (EMSG), adopting a unified interacting quark-matter equation of state that incorporates perturbative QCD corrections, color superconductivity, and finite-strange-quark-mass effects. By solving the modified Tolman-Oppenheimer-Volkoff equations over a broad range of EMSG coupling strengths and interaction parameters, we show that the inclusion of electric charge subs…

詳細を見る →

astro-ph.EP2026年9月19日

Optical Constants of Photochemical Haze Analogs in N2-CH4-CO Atmospheres from 0.4 to 28.6 μm

Zhengbo Yang, Chao He, Haixin Li, Sai Wang, Xiao'ou Luo, Yu Liu, Sarah M. Hörst

Photochemical hazes play an important role in shaping the spectra and radiative balance of N2-dominated planetary atmospheres. We present newly acquired FTIR and retrieved optical constants (N=n+ik) of laboratory-generated haze analogs from N2/CH4 and N2/CH4/CO gas mixtures under plasma discharge conditions. The retrievals use particle densities newly measured for the CH4-series and previously published particle densities for the CO-series. The experiments systematically explored CH4 concentrati…

詳細を見る →

astro-ph.EP2026年9月19日

Characterization of the Compact Multi-planet System TOI-789: Validation of Three Terrestrial Planets, Dynamical Characterization, and Detection of a Fourth Temperate Candidate

Juan F. Pagés Navarrete

We present the validation and dynamical characterization of TOI-789 (TIC 300710077), a compact multi-planet system around an M3 dwarf at 43 pc. Using ~7 yr of TESS photometry (42 sectors), public ground-based follow-up (LCOGT, MEarth), and high-resolution imaging (Gemini/Zorro, SOAR), we statistically validate three terrestrial planets with TRICERATOPS: TOI-789 b (Rp = 1.18 Rearth, P = 5.45 d), c (1.15 Rearth, 8.04 d), and d (1.40 Rearth, 12.97 d), with false-positive and nearby-false-positive p…

詳細を見る →

astro-ph.SR2026年9月19日

Distinct Population of Wolf-Rayet Stars in the Low-Metallicity Galaxy NGC 6822. Quantitative analysis of optical and UV spectra of the complete sample

R. Trigg, L. M. Oskinova, W. -R. Hamann, H. Todt, D. Pauli, T. Shenar, A. A. C. Sander, M. Chatzis et al.

Context: Wolf-Rayet (WR) stars are particularly rare in low-metallicity galaxies and remain poorly understood. Detailed studies of the presumably complete population of WR stars in the nearby Small Magellanic Cloud (SMC) galaxy led to perplexing results. Aims: The nearby galaxy NGC 6822 has a similar metallicity to the SMC, and hence provides an excellent laboratory for a comparative study. We aim to derive the stellar and wind parameters of each known WR star in NGC 6822 by means of quantitativ…

詳細を見る →

astro-ph.HEastro-ph.SRhep-ph2026年9月19日

Dark matter self-annihilation as a hidden energy source in white dwarfs

Alvin Cheuk-Nam Chu, Cheuk-Man Yiu, Ching-Hui Lam, Peter Siu-Hei Cheung, Fong-Ching Ho, Ming-chung Chu

White dwarfs (WDs) are compact remnants of stars, supported by electron degeneracy pressure, and their structures are generally considered to be well understood. Significant discrepancies exist between the theoretical and observed white dwarf mass-radius (MR) relations, especially for hot Q-branch white dwarfs with unexplained heating sources. In this study, we explore the potential of WDs as a portal to dark matter (DM) physics by investigating the effect of self-annihilating DM (SADM) admixed…

詳細を見る →

astro-ph.GA2026年9月19日

The interplay between AGN photo-ionization, radio jet, and star formation in the z $\sim$ 3.5 radio galaxy 4C +03.24

Bruno Dall'Agnol de Oliveira, Dominika Wylezalek, Pranav Kukreti, Wuji Wang, Rogério Riffel, Rogemar A. Riffel, Andrey Vayner, Caroline Bertemes et al.

High-redshift radio galaxies (HzRGs) are among the most powerful radio sources, and are associated with the most massive galaxies and dense environments at redshifts z $\gtrsim$ 1. They are ideal laboratories for studying how Active Galactic Nuclei (AGN) events can shape the evolution of galaxies, as intense radiation, jets, and star formation are simultaneously observed. We present JWST/NIRSpec integral-field spectroscopy ($\sim$ 1.6 kpc spatial resolution) of the 4C +03.24 system, a powerful H…

詳細を見る →

astro-ph.GA2026年9月19日

Mid-Infrared Diagnostics of PAH Processing and Radiation Fields in M33 H II Regions with JWST/MIRI

Puja Porel, Archana Soam, Saikhom Pravash

We present JWST/MIRI (Proposal ID 4297) medium-resolution integral field spectroscopy of five H II regions in the nearby spiral galaxy M33, obtained from the Mikulski Archive for Space Telescopes (MAST). The fully calibrated Level-3 spectral cubes provide continuous wavelength coverage from 6.5 - 20.9~$μ$m, enabling analysis of polycyclic aromatic hydrocarbon (PAH) emission, ionic fine-structure lines, and warm molecular hydrogen. The spectra show prominent PAH bands at 7.7, 8.6, and 11.3~$μ$m,…

詳細を見る →

astro-ph.GA2026年9月19日

The magnetic field in the multi-phase interstellar medium of NGC 6946

Amir Yarahmadi, Fatemeh Tabatabaei, Golshan Ejlali, Rainer Beck, Enrique Lopez-Rodriguez, Alejandro Borlaff

Magnetic fields regulate the multi-phase interstellar medium (ISM) of spiral galaxies, yet their behavior across ISM phases remains poorly constrained observationally. We present a comparative polarimetric study of the nearby spiral galaxy NGC 6946 using far-infrared (FIR) data at 154 $μ$m from SOFIA/HAWC+ and radio continuum data at 6 cm from the VLA and Effelsberg telescopes, which probe magnetic fields in the cold dust-emitting and diffuse synchrotron-emitting phases of the ISM, respectively.…

詳細を見る →

hep-phastro-ph.HE2026年9月19日

Gamma-Ray Echo as a Probe of Supernova Neutrino Emission Anisotropy and Long-Baseline Effects

Garv Chauhan, Cecilia Lunardini, Yago Porto

During a core-collapse supernova (CCSN), the emitted electron antineutrino ($\barν_e$) burst initiates inverse beta decay (IBD) in the outer hydrogen layer of the stellar envelope. This leads to the production of a characteristic 511 keV photon signal, termed the Gamma-Ray Echo. The same neutrino burst, when detected on Earth in large neutrino observatories such as Hyper-Kamiokande, will offer information about the $\barν_e$ content of the neutrino flux reaching Earth. In this work, we show that…

詳細を見る →

astro-ph.SR2026年9月19日

Hard X-Ray Quasi-Periodic Pulsations in X-Class Solar Flares Observed by Aditya-L1/HEL1OS

Sachin Rajkapoor Kanaujiya, Ram Ajor Maurya, Swetha Gopinathan, Valery M. Nakariakov

We present the catalogue of quasi-periodic pulsations (QPPs) detected in hard X-ray (HXR) observations of X-class solar flares obtained with the HEL1OS instrument onboard Aditya-L1 during July 2024 - March 2026. The catalogue comprises 34 flares spanning GOES classes X1.1 - X7.1. QPPs are detected and studied using a uniform procedure based on Ensemble Empirical Mode Decomposition (EEMD) and wavelet analyses. Statistically significant QPPs are identified in 25 events (~74%), demonstrating that Q…

詳細を見る →

astro-ph.COastro-ph.GA2026年9月19日

Feeding the Void: Co-evolution of the SIDM-seeded Black Hole and the dark halo after core-collapse

Zhichao Carton Zeng, Annika H. G. Peter, Louis E. Strigari, Andrew Benson, Xiaolong Du, Charlie Mace

While the gravothermal collapse of self-interacting dark matter (SIDM) halos provides a compelling mechanism for seeding supermassive black holes (BHs), the post-collapse macroscopic co-evolution of the BH and its host halo remains largely unexplored. In this paper, we introduce a novel N-body framework to dynamically model the dark matter accretion onto the central BH. By bracketing the accretion rate with two complementary phenomenological schemes---a `multi-round core-collapse' scenario and a…

詳細を見る →

astro-ph.GAastro-ph.SR2026年9月19日

Dust Growth in Evolving Filamentary Molecular Clouds: Signatures in Ionization, Resistivity, and Infrared Scattering

Hayato Uchimura, Yoshiaki Misugi, Daisuke Takaishi, Taishi Tsuchiyama, Tomoki Tokunaga, Rintaro Shibakawa, Yusuke Tsukamoto

Studies of dust growth in molecular clouds often prescribe the collapse history, leaving unclear how magnetic regulation of core formation shapes dust evolution and its observable and non-ideal MHD signatures. We address this problem by performing one-zone dust evolution and ionization calculations along time-dependent density and magnetic-field histories extracted from three-dimensional non-ideal MHD simulations of core formation through filament fragmentation. A stronger initial magnetic field…

詳細を見る →

hep-phastro-ph.HEhep-exhep-th2026年9月19日

Kaluza--Klein Dark-Photon Mediation of Inelastic Dark Matter at LUX-ZEPLIN

Waqas Ahmed, George K. Leontaris

We study a five-dimensional realization of endothermic dark matter motivated by the recent high-recoil LUX-ZEPLIN event. A pseudo-Dirac Standard-Model singlet fermion is localized in the extra dimension and couples to a bulk $U(1)_D$ gauge field. The same localization that suppresses a distant-brane Majorana operator and generates the inelastic splitting also controls the couplings to the Kaluza--Klein (KK) dark-photon tower, producing a localization-filtered mediator propagator. We organize the…

詳細を見る →

astro-ph.HEgr-qc2026年9月19日

Stereoscopic gravitational-wave probe: Gravitational lensing of a binary merger in active galactic nuclei

Paul Martens, Samson H. W. Leong, Ryan Zhang, Otto A. Hannuksela

Recent work has shown that, if a large fraction of the LIGO-Virgo-KAGRA compact binary coalescences (CBCs) occur in accretion disks around active galactic nuclei (AGNs), many such AGN-CBC systems will likely experience lensing and produce multiple gravitational-wave (GW) "images" of the CBCs that will become detectable with current or future GW detectors. However, the waveforms produced by such lensed "images" will differ from those produced by other lensing systems because the binary source is…

詳細を見る →

astro-ph.EPastro-ph.IM2026年9月19日

The Science Potential of Characterizing Gas Giant Exoplanets with HWO

Beck Dacus, Jean-Baptiste Ruffio, Quinn Konopacky, Renyu Hu, Tyler D. Robinson, Mary Anne Limbach, Kielan Hoch, Katelyn Horstman et al.

With the ability to directly image Earth-like exoplanets and search their atmospheres for biosignatures, the upcoming Habitable Worlds Observatory (HWO) will also collect high signal-to-noise ratio (S/N) reflected-light photometry and spectra of nearby gas giant exoplanets. Such high-quality data would allow novel investigations into gas giant atmospheric composition, formation, and kinematic properties, and could enable the detection of exomoons around these planets. We use the EXOSIMS direct i…

詳細を見る →

gr-qcastro-ph.COastro-ph.HEhep-phhep-th2026年9月19日

Black Holes as Frequency-Dependent Filters of Stochastic Gravitational Waves

Sefi Katznelson, Aidan Minger, Stefano Profumo

Black holes ring when perturbed, whereas their response to a stationary gravitational-wave background is a real-frequency scattering problem, not a source of additional quasi-normal-mode lines. We make this standard distinction quantitative by treating a black hole as a frequency-, angle-, and polarization-dependent filter. For an isotropic stationary background around Schwarzschild holes, elastic scattering produces no net monopole signal, so horizon absorption is the only population-level spec…

詳細を見る →

hep-phastro-ph.HEastro-ph.SR2026年9月19日

New bounds on light scalars from the tip of the red giant branch

Natnael Debru, Audrey Fung, Saniya Heeba, Hugo Schérer, Katelin Schutz, Aaron C. Vincent

Light, weakly coupled particles can be copiously produced in the hot and dense interior of stars, and the resulting energy loss can leave observable imprints on entire stellar populations. For instance, additional energy loss from red giant cores delays helium ignition and brightens the tip of the red giant branch (TRGB). We revisit the TRGB bounds on light scalars coupled to electrons, of which the Higgs portal is the prototypical example. In the degenerate cores of red giants, scalar emission…

詳細を見る →

astro-ph.EPastro-ph.IM2026年9月19日

Exoplanet Atmosphere Spectral Sensitivity Analysis with PICASO: Jacobians, Linear-Gaussian Approximations, and Information Content

Natasha E. Batalha, Nicholas F. Wogan

Designing observatory and instrument architectures for complex missions like the Habitable Worlds Observatory (HWO) requires a rapid and rigorous mathematical framework to evaluate trade-offs across bandpass, spectral resolution, and signal-to-noise regimes. While full Bayesian atmospheric retrievals are the gold standard for atmospheric inference, they are too computationally expensive to explore this full parameter space. Here, we present a sensitivity analysis and retrieval diagnostic toolkit…

詳細を見る →

physics.plasm-phphysics.space-ph2026年9月19日

Interactions Between Two Magnetized Plasma Pressure Filaments: Drift-Alfvén Modes and Transport

Thomas Simala-Grant, Scott Karbashewski, Richard Sydora, Bart Van Compernolle

A set of experiments on merging dynamics of localized magnetized plasma pressure filaments in close proximity has been carried out in a large linear magnetized plasma device. A two filament configuration is used to determine the separation scale of cross-field interaction. Fluctuation analysis of the ion saturation current confirms the presence of unstable drift-Alfvén modes on each filament which are predominantly driven by the steep electron temperature gradient. When the filaments are separat…

詳細を見る →

astro-ph.GA2026年9月19日

Balmer Absorption Series and Broad Metal Lines in Two Luminous Little Red Dots

Bingjie Wang, Jenny E. Greene, Hanpu Liu, Nicholas Kaaz, Gabriel B. Brammer, Raphael E. Hviding, Ivo Labbé, Joel Leja et al.

Balmer absorption is common among little red dots (LRDs), but absorbers at or redward of systemic are rare, occurring in only $\sim10-15$\% of H$α$ absorbers. In this paper, we study two such exceptional cases with deep JWST/NIRSpec spectroscopy: 15 hr of high-resolution (G395H) observations of RUBIES-EGS-49140 (z=6.68), resolving the absorption in all four transitions from H$α$ through H$δ$, and medium-resolution spectroscopy (10 hr of G235M, 2 hr of G395M) of UNCOVER-A2744-45924 (z=4.46; 1.7x…

詳細を見る →

astro-ph.EPastro-ph.GA2026年9月19日

Post-perihelion Photometric and Spectroscopic Monitoring of the Interstellar Comet 3I/ATLAS

Goldy Ahuja, Shashikiran Ganesh, K. Aravind, Emmanuel Jehin, Bhavya Ailawadhi, Vikrant K. Agnihotri, B. Arvind, Pallavi Saraf et al.

The third interstellar object, comet 3I/ATLAS, was observed using various Indian telescopes during its post-perihelion evolution. We carried out imaging and spectroscopic observations of the comet at multiple epochs using the 0.5-m, 1.2-m, and 2.5-m telescopes of the Physical Research Laboratory and the 2-m Himalayan Chandra Telescope (HCT) operated by the Indian Institute of Astrophysics. Additionally, time-series photometry was obtained on 7 epochs using the 0.132-m refractor of Cepheid Observ…

詳細を見る →

astro-ph.HE2026年9月19日

Resolving the Galactic Center Region's Gamma-Ray Emission and Searching for its Neutrino Counterpart with HAWC and IceCube

S. Yun-Carcamo, R. Babu, for the HAWC, IceCube collaborations

The Galactic Center (GC) is a prime candidate for petaelectronvolt cosmic-ray acceleration, with gamma-ray emission observed by the High Altitude Water Cherenkov (HAWC) Observatory extending beyond 100 TeV. We present an analysis of the GC using ~2860 days of HAWC data, with increased exposure and improved sensitivity relative to previous results. The best-fit gamma-ray emission model includes a point source (HAWC J1745-2857) and a Galactic diffuse emission component. Assuming a hadronic origin,…

詳細を見る →

astro-ph.HE2026年9月19日

The chirping of Lense-Thirring precession in tidal disruption event accretion flows

Andrew Mummery, Eliot Quataert

Tidal disruption event X-ray light curves do not appear to show clear signs of periodic modulation. This is naively somewhat surprising since the stars that are disrupted originate at large scales in the galaxy where they cannot know about the orientation of the black hole spin axis. This should lead to the formation of a misaligned disk that precesses due to Lense-Thirring torques, modulating X-ray emission from the inner disk regions. We argue that in fact the properties which are required for…

詳細を見る →

astro-ph.IM2026年9月19日

Initial modeling and testbed feasibility studies of WaveDriver: a laser guide star AO system for HWO

Dominic F. Sanchez, Benjamin L. Gerard, Peter Waswa, Alex Geringer-Smith, Aditya Sengupta, Alexx Perloff, Michael Messerly, William Moore et al.

The Habitable Worlds Observatory (HWO) will require $>100\times$ greater wavefront stability than achieved by JWST, pushing conventional telescope architectures to picometer-level performance limits. WaveDriver is a mission concept that relaxes these constraints by employing an external laser guide star (LGS) spacecraft flying in formation with HWO to enable wavefront sensing and control. Early results from the High Contrast Testbed demonstrate feasibility of required stability using coronagraph…

詳細を見る →

physics.plasm-phastro-ph.SR2026年9月19日

Proton Heating Rates in the Inner Heliosphere: Helios Observations

Alaa Fayad, Anna Tenerani, Chadi Salem

Solar wind protons exhibit a temperature anisotropy that deviates from the double-adiabatic prediction, suggesting an additional energy source. To investigate solar wind heating mechanisms, we analyze Helios 1 and 2 data and characterize the radial evolution of the adiabatic invariants and anisotropic heating rates of fast wind protons, considering both the bulk population and its core and beam components separately. Unlike previous studies, we account for proton heat fluxes and deviations from…

詳細を見る →