研究動向

astro-ph.IM2026年8月20日

Design, assembly, and initial test results of a cryostat for holographic characterization of microwave telescopes

Jon E. Gudmundsson, Miranda Eiben, Thomas J. L. J. Gascard, Eve M. Vavagiakis

We describe the design, fabrication, assembly, and room-temperature vacuum qualification of a 1.4-m long cylindrical cryostat developed for holographic testing of cryogenic microwave telescope optics. The system consists of a welded 6061-aluminum vacuum vessel containing nested 45- and 4-K aluminum radiation shields, cooled by a two-stage pulse-tube cryocooler through commercial OFHC copper flexible thermal straps. The intermediate 45-K stage intercepts radiative, conductive, and wiring heat loa…

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astro-ph.HE2026年8月20日

The intrinsic luminosity-decay correlation in subsamples of GRB X-ray afterglows

S. P. R. Shilling, S. R. Oates, J. L. Racusin, B. Cenko, R. Gupta, P. Nuessle, M. Smith, G. P. Lamb et al.

The intrinsic luminosity-decay correlation in gamma-ray burst (GRB) afterglows, between the early-time luminosity and the average rate of decay past this time, has previously been observed in the radio, optical/UV, X-ray and GeV wavebands and quantitatively shows that more luminous afterglows tend to have higher average rates of decay. We have compiled an updated sample of 427 X-ray afterglows with measured redshifts, observed with Swift/XRT over 20 years. For each GRB, we measure the luminosity…

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astro-ph.EPastro-ph.SR2026年8月20日

Substructure evolution from protoplanetary to debris disks driven by mutually gravitating planetesimals and implications on Kepler resonances and free-floating planets

Yinuo Han, Konstantin Batygin, Fei Dai

Motivated by recent observations suggesting rings found in debris disks are wider than those in protoplanetary disks, we consider a picture in which planetesimals formed in radially narrow dust traps radially diffuse into debris rings via mutual scattering. Under this picture, evolving the fractional widths ($Δr/r$) of resolved debris rings back to a few Myr according to the theoretical $t^{1/5}$ evolutionary trajectory reproduces the protoplanetary ring distribution. We inferred the product of…

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astro-ph.EP2026年8月20日

The Effects of M Star Age Dependent Ultraviolet Emission on Detecting and Interpreting Exoplanet Biosignatures

C. Evan Davis, Victoria S. Meadows, Evgenya L. Shkolnik, Andrew P. Lincowski, Sarah Peacock, R. O. Parke Loyd, Adam C. Schneider, Travis Barman et al.

Given their abundance and observational advantages, M stars will arguably be the best candidates for characterizing and searching for biosignatures on terrestrial exoplanets in the near future. However, photochemistry that can suppress or enhance key biosignature molecules in planetary atmospheres is primarily driven by UV flux from the host M star, which is influenced by stellar activity that decreases with age. Here, we simulate Pre-Industrial Earth-like and Archean Earth-like atmospheres arou…

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astro-ph.GA2026年8月20日

Serendipitous discovery of an almost-dark galaxy in the Virgo Cluster

Minh Ngoc Le, Ignacio Trujillo, Sergio Guerra Arencibia, Ignacio Ruiz Cejudo, Junais, Mireia Montes, Johan H. Knapen, Željko Ivezić et al.

Analogues of extreme Local Group galaxies with very low surface brightness and large effective radii must exist elsewhere, still hidden due to current detection limits. We report the serendipitous discovery of a low-mass almost-dark galaxy TTT J1237327+143535 in the Virgo Cluster, observed using the Two-meter Twin Telescope at the Teide Observatory. TTT J1237327+143535 has a central surface brightness of $27.9 \pm 0.2 \, \mathrm{mag arcsec}^{-2}$ in the $g'$-band, an effective radius of $0.9 \pm…

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astro-ph.GAastro-ph.COhep-ph2026年8月20日

Detectable subhalo impacts in Milky Way streams

Junyang Lu, Elias Bernreuther, Tongyan Lin, Vincent S. H. Lee, Ana Bonaca, Ethan O. Nadler

Dark matter subhalos leave gravitational imprints in the stellar streams of the Milky Way. Observing individual strong impacts of subhalos offers a compelling way to constrain and discover potentially dark subhalos down to $10^6 M_\odot$, allowing for new tests of the particle physics properties of dark matter. We develop a pipeline and statistical framework to forecast the expected number of detectable subhalo impacts on stellar streams, based on morphological and kinematic data from surveys su…

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astro-ph.GAastro-ph.CO2026年8月20日

Low Ly$α$ Visibility in Galaxy Overdensities: Reionization Topology and Neutral-Fraction Ceilings from DIVER over $4.8<z<11$

Yongda Zhu, Xiaohui Fan, Laura C. Keating, George D. Becker, Eiichi Egami, Xiaojing Lin, Fengwu Sun, Christopher Cain et al.

Ly-alpha emission is widely used to trace cosmic reionization, but its interpretation depends on how Ly-alpha visibility varies with galaxy environment. We use deep JWST/NIRSpec observations from Deep Insights into UV Spectroscopy at the Epoch of Reionization (DIVER) in GOODS-N to measure Ly-alpha visibility for 250 galaxies at 4.8 25 A. We combine these measurements with H-alpha and [O III] emitters from JWST/NIRCam wide-field slitless spectroscopy to map the density field around each DIVER gal…

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astro-ph.GA2026年8月20日

The THESAN-ZOOM project: clumpiness of high-redshift galaxies and its connection to bursty star formation

Zihao Wang, Xuejian Shen, Rahul Kannan, Ewald Puchwein, Aaron Smith, Josh Borrow, Enrico Garaldi, Laura Keating et al.

Recent JWST observations have revealed diverse high-redshift galaxy morphologies, including a population with irregular and clumpy structures. The physical origin of these structures, and the extent to which observational biases shape their appearance, remain uncertain. We present a power-spectrum-based method for quantifying galaxy clumpiness across spatial scales, using the radiation-hydrodynamic simulation suite THESAN-ZOOM, which employs a state-of-the-art galaxy formation model that resolve…

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astro-ph.GA2026年8月20日

Diffuse HI emission in the circumgalactic medium of NGC891 and NGC4565 - III: azimuthal profiles

Mary Rickel, Sanskriti Das, Nickolas M. Pingel, D. J. Pisano, Adam Leroy, Smita Mathur, George Heald

Diffuse HI emission in the circumgalactic medium (CGM) of NGC891 and NGC4565 has been previously shown to trace an inflow along minor axes pointings and to co-rotate with the HI disk along major axes pointings out to ~100 kpc (Das2020b,Das2024a). To obtain a 360$^\circ$ view of the inner neutral CGM ($\rm < 25 kpc$ for NGC891, $\rm < 30 kpc$ for NGC4565), we perform deep stare observations with the Green Bank Telescope (GBT) along the off-axes, 45$^\circ$ between principal axes, achieving a 5$σ$…

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astro-ph.IMphysics.optics2026年8月20日

Effects of manufacturing tolerances on the performance of metamaterial microwave anti-reflection coatings

Rustam Balafendiev, Miranda Eiben, Jon E. Gudmundsson

Metamaterial anti-reflection coatings (ARC) are used in a variety of applications, including: lenses, filters, and absorbers. Typically, the design of a given ARC is done within an infinite medium approximation, which presupposes that every unit cell on the interface is identical. However, in realistic applications, the geometry of a given ARC usually has some degree of variability, be it due to the shape of the surface inherent to the application, like in a lens, or manufacturing tolerances. Th…

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astro-ph.GAastro-ph.CO2026年8月20日

Inferring the Dark from the Observable: Estimating Halo Masses Using Galaxy Properties

Alice Chen, Syeda Lammim Ahad

The formation and evolution of galaxies are interconnected with that of their host halos. Given this closely related evolutionary history, it should follow that galaxy properties are correlated with their host halo mass. Previous works have shown that star formation rates of galaxies in cluster halos differ systematically from those in field halos, suggesting that host halo mass plays a significant role in the history of galaxy evolution. Here, we examine the correlations between observable gala…

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astro-ph.EP2026年8月20日

No Persistent Helium Absorption in LHS 1140 b: Four JWST/NIRISS SOSS Transits and Multi-epoch Stellar He I Variability

Amélie Gressier, Charles Cadieux, René Doyon, Louis-Philippe Coulombe, Romain Allart, Étienne Artigau, François Bouchy

The search for atmospheres on temperate terrestrial planets is important for understanding how these objects form and evolve, and their potential habitability. Recent transit observations of LHS 1140 b, a temperate ($T_{\rm eq}=226$ K) planet straddling the radius valley ($R_{\rm p}\approx1.7 R_\oplus$), with the WINERED high-resolution spectrograph yielded a detection of planetary atmospheric escape through the measurement of excess absorption ($1.24\pm0.23\%$) in the metastable helium triplet,…

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physics.ins-detastro-ph.IM2026年8月20日

Identifying Cost-Favorable Locations for Cosmic Explorer

Laurence Datrier, Geoffrey Lovelace, Tooba Ansar, Lance Blagg, Warren Bristol, Matthew Evans, Chris Lukinbeal, Vuk Mandic et al.

Cosmic Explorer (CE) is a proposed next-generation gravitational-wave observatory that aims to extend our gravitational-wave vision to the edge of the observable universe. With a foundation of technology proven by the National Science Foundation's Laser Interferometer Gravitational-Wave Observatory (LIGO), CE will observe black holes and neutron stars across cosmic time, explore the nature of extreme matter with high fidelity, and probe the nature of gravity and fundamental physics. CE's referen…

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astro-ph.IMastro-ph.HE2026年8月20日

Real-Time RFI Mitigation in SPOTLIGHT: A Two-Stage Approach for Transient Searches

Raghav Wani, Jayanta Roy, Harshavardhan Reddy, Sanjay Kudale, Ujjwal Panda, Karel Adamek, Wesley Armour, Kshitij Bane et al.

Radio Frequency Interference (RFI) remains one of the primary challenges limiting the sensitivity and reliability of modern radio transient surveys, particularly for real-time searches of fast radio transients. The SPOTLIGHT system is a commensal real-time transient search backend operating at the upgraded Giant Metrewave Radio Telescope (uGMRT), where robust and computationally efficient RFI mitigation is essential for sustained operations. We present the real-time two-stage RFI mitigation fram…

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astro-ph.EP2026年8月20日

Wet Removal and Cloud Enhancement: The Microphysics of Cloud-Haze Interactions on Sub-Neptunes

Vighnesh Nagpal, Maria Steinrueck, Diana Powell, Peter Gao, Dominic Samra, Wolf Cukier

Aerosols are a near-ubiquitous feature of sub-Neptune atmospheres, yet their microphysical nature remains poorly understood. Both condensate clouds and photochemical hazes have been proposed to explain observations, but have largely been studied in isolation. Here we present a new bin-scheme microphysical model, adapted from CARMA, that couples cloud and haze formation through heterogeneous nucleation - the dominant mode of cloud formation in the Solar System - in which haze particles act as clo…

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astro-ph.SR2026年8月20日

Asteroseismology of the multiperiodic field SX Phe pulsator BL Camelopardalis

W. Szewczuk, J. Daszyńska-Daszkiewicz, P. Walczak, E. Rodríguez

BL Camelopardalis (BL Cam) is the most metal-poor SX Phoenicis star known in the Galactic field, making it an excellent test bed for studies of Population II stellar structure and evolution, as well as for investigating the formation channels of blue straggler stars. We aim to constrain fundamental stellar parameters and pulsational properties of BL Cam and identify the nature of its observed oscillation modes. We analysed high-precision space-based data from the TESS mission and long-term groun…

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astro-ph.SR2026年8月20日

Multi-lane type II radio bursts: Insights into shock propagation in the corona

Nadiya K., Divya Paliwal, Anshu Kumari

Type II solar radio bursts are considered as the signatures of the coronal shocks. These bursts are generated from plasma waves excited by magnetohydrodynamic (MHD) shocks, and then converted into radio waves at the local plasma frequency and/or its harmonics. Hence, these bursts often have fundamental-harmonic (FH) and band-splitting (SB) structures, which provide insights into shock generation and propagation in the corona, hence, in turn, the corresponding coronal conditions. In the present s…

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astro-ph.SRastro-ph.HE2026年8月20日

The Ultrafast Line-Driven Wind from the Double-Degenerate Merger Remnant WD J005311

Kazuma Kato, Kazumi Kashiyama

We systematically construct steady-state wind solutions for double-degenerate merger remnants consisting of a degenerate oxygen-neon core and an optically thick expanding envelope powered by carbon-shell burning, with winds accelerated by radiation pressure including line driving. For a given envelope composition, each solution is characterized by two eigenvalues: the degenerate core mass, $M_{\rm WD}$, and the total envelope and wind mass, $ΔM$. We find that wind solutions exist for $M_{\rm WD}…

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astro-ph.EP2026年8月20日

A Search for helium in the atmospheres of three sub-Neptunes and a super-Earth around M-dwarfs

Kiyoe Kawauchi, Norio Narita, Yuichi Ito, Akifumi Nakayama, Teruyuki Hirano, Masayuki Kuzuhara, Mayuko Mori, Izuru Fukuda et al.

Thousands of sub-Neptunes have been discovered mainly through space-based surveys such as Kepler and TESS. Their bulk compositions and internal structures are thought to reflect their formation and evolutionary pathways, and atmospheric observations provide constraints on these processes. The near-infrared helium triplet is a potential tracer of extended, escaping H/He atmospheres. Recent models that include geometric effects suggest that planets orbiting nearby late M dwarfs may offer favorable…

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astro-ph.HEhep-phhep-thnucl-th2026年8月20日

Quantifying uncertainty in the neutron-star equation of state using point estimates and posterior distributions

André Gonçalves da Silva, Ricardo Luciano Sonego Farias

We investigate uncertainty quantification for the neutron-star equation of state (EOS) by comparing point-estimation and distributional inference approaches using the same Chebyshev and piecewise-linear parameterizations. We combine neutron-star mass--radius and gravitational-wave tidal-deformability information within Bayesian, multilayer-perceptron (MLP), and normalizing-flow frameworks. Although the methods yield similar mean EOS behavior, the deterministic MLP produces substantially narrower…

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astro-ph.GA2026年8月20日

The progenitors of $z\gtrsim10$ JWST galaxies in the COLIBRE simulations

Evgenii Chaikin, Andrew Pontzen, Carlos S. Frenk, Joop Schaye, Shengdong Lu, Robert A. Crain, Anna Durrant

JWST has revealed a large population of luminous galaxies ($M_{\rm UV}\lesssim -20$) at redshifts $z \gtrsim 10$, widely interpreted as posing a challenge to models of galaxy formation within the $Λ$CDM cosmology. Here, we search for counterparts of the JWST galaxies in the COLIBRE simulations of galaxy formation. Although these simulations have not been tuned to reproduce any $z > 0$ observations, we find a population of COLIBRE galaxies with properties similar to those of the JWST galaxies, an…

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astro-ph.IM2026年8月20日

Physical Optics Analysis of Polarization Effects in SO LAT Reflectors

Xiaodong Ren, Patricio A. Gallardo, Jon E. Gudmundsson

We present a physical-optics analysis of the polarization response of the reflective optical of the Simons Observatory Large Aperture Telescope (SO LAT). Far-field co-polar and cross-polar beam patterns are simulated for representative feedhorn positions, and the corresponding polarization-angle offsets are evaluated. The results show that the crossed-Dragone reflector system has good polarization performance. Off-axis feed positions introduce small, position-dependent offsets in the far-field p…

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astro-ph.SR2026年8月19日

Quadrupole White-light Sources in an X1.2 Flare Observed by ASO-S/LST/WST and SDO/HMI

Zhichen Jing, Ying Li, Dechao Song, Qiao Li, Zhengyuan Tian

We present observations of an X1.2 white-light flare on 2023 January 6, which exhibits a rare quadrupolar white-light source configuration. This event was observed by the White-light Solar Telescope (WST; 3600 Å) aboard the Advanced Space-based Solar Observatory and the Helioseismic and Magnetic Imager (HMI; 6173 Å) aboard the Solar Dynamics Observatory. Four flare-related footpoints (labeled as FP1--FP4) were nearly simultaneously identified in both WST 3600 Å and HMI 6173 Å continua, associate…

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astro-ph.COastro-ph.IM2026年8月19日

Towards end-to-end Bayesian forward models in global 21-cm cosmology: surrogate modelling and marginalisation of beam uncertainty

Jacob L. Tutt, Dominic J. Anstey, John Cumner, Harry T. J. Bevins, Jean Cavillot, Eloy de Lera Acedo

Robust statistical inference in global 21-cm cosmology requires end-to-end uncertainty quantification that jointly handles the highly degenerate cosmological signal, foreground emission, and instrumental response. Although electromagnetic simulations capture physical antenna properties in a parametrised way, multi-hour runtimes make their integration within likelihood-based sampling frameworks infeasible. Most existing approaches therefore assume a single precomputed beam, a fragile assumption g…

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astro-ph.HE2026年8月19日

Constraining Cosmic-Ray Acceleration and Escape in Middle-Aged Supernova Remnants with GeV-TeV Gamma-Ray Observations

Siyu Chen, Bing Theodore Zhang, Yi Xing, Siming Liu

In this work, we perform a systematic, time-dependent study of the gamma-ray emission from four representative middle-aged SNRs (W51C, IC~443, W44, W28), incorporating both CRs within the remnant shells and escaped CRs interacting with surrounding molecular clouds. We compare our results with GeV--TeV gamma-ray observations from Fermi-LAT, H.E.S.S., MAGIC, and LHAASO, including a dedicated analysis of the Fermi-LAT data for regions A and B associated with W28. We find that the observed spectra f…

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astro-ph.IMastro-ph.EP2026年8月19日

Asgard/NOTT: Status of laboratory nulling performance

T. Mattheussen, R. Laugier, D. Defrère, G. Garreau, P. Chingaipe, G. Raskin, M. Salman, K. Missiaen et al.

Nulling interferometry enables the direct detection of faint companions and circumstellar structures at angular separations unresolvable by classical, diffraction-limited imagers, whilst dramatically improving the measurable contrast. The Asgard/NOTT nulling instrument aims to achieve a contrast performance of 10^-5 in the L' wavelength band (3.5 - 4.0 μm), enabling observation and characterization of young giant exoplanets near the snowline and hot exozodiacal dust. Previous studies have verifi…

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astro-ph.IM2026年8月19日

First demonstration of a multimode-to-multimode photonic lantern for astronomy

Marina Centenera-Merino, Andrew Ross-Adams, Christopher Betters, Pedro J. Amado, Jesus Aceituno, Kalaga Madhav, Stefan Cikota, F. Javier Flores et al.

Photonic lanterns have been widely used in astronomy as low-loss multiplexing devices, typically coupling light from a multimode input into several single-mode outputs. In this work, we present the first multimode-to-multimode photonic lantern specifically designed to combine light from several multimode fibers into a single multimode waveguide. We fabricated and characterized the devices at multiple wavelengths to evaluate the performance of the adiabatic multimode transition. The measured effi…

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astro-ph.GAastro-ph.HE2026年8月19日

The efficient star-forming regions of stripped-envelope supernovae

M. Solar, M. J. Michałowski, J. Nadolny, L. Galbany, J. P. Anderson, J. Sollerman, T. Pessi, E. Zapartas et al.

Massive stars ($> 8~\rm{M}_{\odot}$) play a key role in shaping the interstellar medium of galaxies through stellar feedback. However, how these stars form and evolve before exploding as core-collapse supernovae (SNe) remains elusive. We compute for the first time the star-formation efficiencies (SFEs) at the locations of hydrogen-rich (H-rich) SNe and stripped-envelope SNe (SESNe) to constrain their progenitor properties. We used VLT/MUSE and ALMA observations of H$α$/H$β$ and CO(2-1) emission…

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astro-ph.IM2026年8月19日

VERITAS 2.3.1: Optimisation and Characterisation of the Enhanced Readout ASIC for the NewAthena Wide Field Imager

Ajay Kumar Dakshinamurthy, Sven Herrmann, Peter Orel, Anna-Katharina Schweingruber, Astrid Mayr, Johannes Muller-Seidlitz, Jonas Reiffers, Sebastian Albrecht et al.

VERITAS 2.3.1 is the next iteration of the VErsatile Readout based on Integrated Trapezoidal Analogue Shapers (VERITAS) integrated circuit (IC) architecture for high-speed, low-noise readout of DEPleted Field Effect Transistor (DEPFET) detectors in the Wide Field Imager (WFI) on ESA's NewAthena X-ray satellite. Building on VERITAS 2.3, which demonstrated a short processing time of 2.5 us per readout and a system noise target of about 3 e- ENC RMS, the VERITAS 2.3.1 revision has been improved wit…

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astro-ph.IMastro-ph.COgr-qc2026年8月19日

Estimation of systematic error from bulk deformation of end test mass induced by photon calibrator for LIGO post-O5 gravitational wave projects

Daiki Tanabe, Aloysius Niko, Kun-Yao Chang, Yuki Inoue, Dripta Bhattacharjee, Richard Savage, Henry Tsz-King Wong

We studied the bulk deformation of the end test masses (ETMs) of gravitational wave (GW) detectors caused by calibration devices named Photon Calibrator (Pcal). This bulk deformation is one of the source of calibration error since it induces non-linear displacement from the ideal pendulum motion of the ETM. Particularly, it is the dominant error source above 1500 Hz which is crucial to the studies of neutron star mergers. The displacement also depends on beam offsets of the main interferometer (…

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