Negative / Null Result ReportOpen accessPhysics and Astronomy
Francesco D’Eugenio, Ignas Juodžbalis, Xihan Ji et al. · 2025 · Monthly Notices of the Royal Astronomical Society
ABSTRACT We present a ‘Little Red Dot’ (LRD) broad-line active galactic nucleus (AGN) at $z=5.077 $, observed with NIRSpec/MSA (micro-shutter assembly) and NIRSpec/IFU (integral-field unit) by the JADES (JWST Advanced Deep Extragalactic Survey) and BlackTHUNDER (Black holes in THe early Universe aNd their DensE surRoundings) surveys. Combining spatially resolved and high-resolution spectroscopy, we characterize its central engine, host, and environment. H$\alpha $ has multiple components, including two broad Gaussians, yielding a black-hole mass $\log (M_{\bullet }/{\rm M}_\odot) = 7.65 $, whi
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Anonymous, G. Baltus, Sarah Caudill et al. · 2026 · Physical review. D/Physical review. D.
We perform a search for binary black hole mergers with one sub-solar mass (SSM) black hole and a primary component above $\sim 2 M_\odot$ in data from the second observing run (O2) of the LIGO-Virgo detectors. Our analysis extends the parameter space explored by previous LIGO-Virgo Collaboration searches for binaries containing SSM components into a region of parameter space motivated by broad mass distributions of primordial black holes (PBHs) exhibiting a peak around $[2-3] M^{}_\odot$, which can arise from the reduction of the equation of state during the QCD phase transition in the early U
View details →Negative / Null Result ReportPhysics and Astronomy
X. J. Li, Desheng Zhao, Desheng Jiang et al. · 2014 · Journal of Applied Physics
The significant effect of the thickness of Ni film on the performance of the Ohmic contact of Ni/Au to p-GaN is studied. The Ni/Au metal films with thickness of 15/50 nm on p-GaN led to better electrical characteristics, showing a lower…
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Fengqiu Adam Dong, Kaitlyn Shin, Casey Law et al. · 2025 · The Astrophysical Journal Letters
Abstract We report the discovery of CHIME J1634+44, a long-period radio transient (LPT) unique for two aspects: it is the first known LPT to emit fully circularly polarized radio bursts, and it is the first LPT with a significant spin-up. Given that high circular polarization (>90%) has been observed in FRB 20201124A and in some giant pulses of PSR B1937+21, we discuss the implications of the high circular polarization of CHIME J1634+44 and conclude its emission mechanism is likely to be “pulsar-like.” While CHIME J1634+44 has a pulse period of 841 s, its burst arrival patterns are indicati
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Aayush Saxena, Alex J. Cameron, Harley Katz et al. · 2026 · Monthly Notices of the Royal Astronomical Society
ABSTRACT The ultraviolet (UV) continuum slope of galaxies, $\beta$, is a powerful diagnostic of the metallicity and ages of stars, nebular gas properties, dust content, and the escape of Lyman continuum (LyC) photons. In this study, we present $\beta$ measurements for 395 spectroscopically confirmed galaxies at $5 \lt z \lt 14.3$ selected primarily from JADES, using high-quality JWST (James Webb Space Telescope) NIRSpec/PRISM spectra. We find a median $\beta = -2.15$, finding a mild increase in blueness of $\beta$ with increasing redshift and fainter UV magnitudes. Interestingly, we find evide
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Sara Kurkowska, Julia Brosch-Lenz, Yuni K. Dewaraja et al. · 2025 · Journal of Nuclear Medicine
Individualized radiopharmaceutical therapies guided by patient-specific absorbed dose (AD) assessments using nuclear medicine imaging have the potential to improve both efficacy and safety. Understanding sources of variability in AD calculations is critical for standardization. The Society of Nuclear Medicine and Molecular Imaging Dosimetry Task Force launched the 177Lu Dosimetry Challenge to evaluate variability across steps within the dosimetry workflow. This work aimed to assess the variability in ADs due to different fitting and integration methods. Methods: Anonymized datasets from 2 pati
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Chuneeta D. Nunhokee, Donald M. Null, Cathryn M. Trott et al. · 2025 · The Astrophysical Journal
Abstract This paper presents the spherically averaged 21 cm power spectrum derived from Epoch of Reionization (EoR) observations conducted with the Murchison Widefield Array (MWA). The analysis uses EoR0-field data, centered at (R.A. = 0 h , decl. = −27 ∘ ), collected between 2013 and 2023. Building on the improved methodology described in C. M. Trott et al. (2024), we incorporate additional data quality control techniques introduced in C. D. Nunhokee (2020). We report the lowest-power-level limits on the EoR power spectrum at redshifts z = 6.5, z = 6.8, and z = 7.0. These power levels, measur
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Gonzalo Morrás, G. Pratten, P. Schmidt · 2026 · The Astrophysical Journal Letters
Abstract The observation of gravitational waves (GWs) from merging black holes and neutron stars provides a unique opportunity to discern information about their astrophysical environment. Two signatures that are considered powerful tracers to distinguish between different binary formation channels are general relativistic spin-induced orbital precession and orbital eccentricity. Both effects leave characteristic imprints in the GW signal that can be extracted from observations. To date, neither precession nor eccentricity has been confidently discerned in merging neutron star–black hole binar
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Callum T. Donnan, Mark Dickinson, Anthony J. Taylor et al. · 2025 · The Astrophysical Journal
Abstract We present JWST/NIRSpec PRISM observations of three luminous ( M UV < −20) galaxies at z ∼ 10 observed with the CANDELS-Area Prism Epoch of Reionization Survey (CAPERS) Cycle 3 program. These galaxies exhibit extreme UV slopes compared to typical galaxies at z = 10. Of the three sources, two of them are a close pair (0 . ″ 22) of blue galaxies at z = 9.800 ± 0.003 and z = 9.808 ± 0.002 with UV slopes of β = −2.87 ± 0.15 and β = −2.46 ± 0.10, respectively, selected from PRIMER COSMOS NIRCam imaging. We perform spectrophotometric modeling of the galaxies, which suggests extre
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R. J. Stewart, George Younes, A. K. Harding et al. · 2025 · The Astrophysical Journal Letters
Abstract We report on IXPE and NuSTAR observations beginning 40 days after the 2024 outburst onset of magnetar 1E 1841−045, marking the first IXPE observation of a magnetar in an enhanced state. Our spectropolarimetric analysis indicates that both a blackbody (BB) plus double power-law (PL) and a double blackbody plus power-law spectral model fit the phase-averaged intensity data well, with a hard PL tail (Γ = 1.19 and 1.35, respectively) dominating above ≈5 keV. For the former model, we find the soft PL (the dominant component at soft energies) exhibits a polarization degree (PD) of ≈30% whil
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Chloe E. Pugh · 2026 · Kyoto University Research Information Repository (Kyoto University)
Quasi-periodic pulsations (QPPs) are a phenomenon commonly observed in solar flares, and are also occasionally observed in stellar flares. They are time variations in the intensity of the flare emission that repeat with approximately…
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Andrei Kudriashov, Xiong Zhou, Razmik A. Hovhannisyan et al. · 2025 · Science Advances
Josephson junctions (JJs) are key to superconducting quantum technologies and the search for self-conjugate quasiparticles potentially useful for fault-tolerant quantum computing. In topological insulator (TI)–based JJs, measuring the current-phase relation (CPR) can reveal unconventional effects such as Majorana bound states (MBS) and nonreciprocal transport. However, reconstructing CPR as a function of magnetic field has not been attempted. Here, we present a platform for field-dependent CPR measurements in planar JJs made of NbSe 2 and few-layer Bi 2 Se 3 . When a flux quantum Φ 0 thr
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Hanjie Tan, Xiaoran Yan, Jian‐Yang Li · 2026 · The Astrophysical Journal Letters
Abstract 3I/ATLAS is an interstellar object whose activity provides critical insights into its composition and origin. However, due to its orbital geometry, the object is too close to the Sun near perihelion to be observed from the ground, and space-based measurements are therefore required. Here we characterize the water production rate of 3I/ATLAS using Solar and Heliospheric Observatory/SWAN Ly α observations from 2025 November to December (heliocentric distances 1.4–2.2 au) with 3D Monte Carlo modeling. We report a peak postperihelion water production rate of Q H 2 O ≈ 4 × 1 0 28 molecules
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Matthias Klein, J. J. Mohr, C. T. Davies · 2024 · Astronomy and Astrophysics
Galaxy clusters are useful cosmological probes and interesting astrophysical laboratories. As the cluster samples continue to grow in size, a deeper understanding of the sample characteristics and improved control of systematics becomes more crucial. For this analysis we created a new and larger ACT-DR5-based thermal Sunyaev–Zel’dovich Effect- (tSZE-) selected galaxy cluster catalog with improved control over sample purity and completeness. We employed the red sequence based cluster redshift and confirmation tool MCMF together with optical imaging data from the Legacy Survey DR-10 and infrared
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C.L. Wilson, J. Astbury, M.J. Ginsberg et al. · 2026 · Nuclear Fusion
Abstract To support the pre-concept design of Tokamak Energy’s (TEs) ST-E1 fusion power plant, we developed a new systems code, PyTok. PyTok codifies plasma physics and engineering constraints within a pure Python, object-oriented framework designed for rapid design iteration and exploration of the power-plant parameter space. The code base and its human- and machine-readable data structures enable coupling to external physics codes and data-analysis tools. Informed by TEs design philosophy and techno-economic analyses, the code was used to identify an initial reference design point for ST-E1.
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Richard Stiskalek, Harry Desmond, Julien Devriendt et al. · 2025 · Monthly Notices of the Royal Astronomical Society
ABSTRACT The peculiar velocity field of the local Universe provides direct insights into its matter distribution and the underlying theory of gravity, and is essential in cosmological analyses for modelling deviations from the Hubble flow. Numerous methods have been developed to reconstruct the density and velocity fields at $z \lesssim 0.05$, typically constrained by redshift-space galaxy positions or by direct distance tracers such as the Tully–Fisher relation, the Fundamental Plane, or Type Ia supernovae. We introduce a validation framework to evaluate the accuracy of these reconstructions
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Lucy R. Ivey, J. Scholtz, A. Lola Danhaive et al. · 2026 · Monthly Notices of the Royal Astronomical Society
ABSTRACT A majority of JWST/NIRSpec integral field unit (IFU) studies at high redshifts to date have focused on UV-bright or massive objects, while our understanding of low-mass galaxies at early cosmic times remains limited. In this work, we present NIRSpec/IFU high-resolution observations of two low-mass ($M_*< 10^9 \ \mathrm{ M}_\odot$), low-metallicity ($[12+\log (\mathrm{O/H})]< 8$) galaxies at $z\sim 7.66$, one of which we identify as hosting a Type-II active galactic nucleus (AGN). We measure flat strong-line metallicity gradients, suggestive of interstellar medium redistribution by out
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Asifa Ashraf, M. Yousaf, Chengxun Yuan et al. · 2026 · The European Physical Journal C
Abstract In this draft, we investigate constant redshift function Morris–Thorne-like traversable wormhole (WH) models which described as a relativistic static fluid distribution in Schwarzschild-type coordinates with a topological global monopole charge under the influence of D -dimensional Einstein gravity. In this scenario we consider three distinct shape functions, while matter sector is supported by anisotropic fluid configuration. We show some basic criteria for the viability of all three shape function models, the radial null energy condition is generally violated while tangential compon
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Chris J. Willott, Yoshihisa Asada, Kartheik G. Iyer et al. · 2025 · The Astrophysical Journal
Abstract We present JWST observations of a gravitationally lensed, extremely metal-poor galaxy at redshift z = 8.203 ± 0.001 from the CANUCS survey. Based on the low oxygen to Balmer line ratios, we infer a gas-phase metallicity of 12 + log(O/H) = 6.85 (1.4% solar), making CANUCS-A370-z8-LAE one of the most metal-poor galaxies known at z > 7. The galaxy has a high H β equivalent width of 225 ± 50 Å, small half-light radius of only r hl = 3 8 − 19 + 3 pc, and high star formation rate density of 50–100 M ⊙ yr −1 kpc −2 . The galaxy shows high-equivalent-width Ly α emission with an i
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Cailin Plunkett, S. Vitale, T. A. Callister et al. · 2026 · Physical Review Letters
Repeated black-hole mergers in dense stellar clusters are a plausible mechanism to populate the predicted gap in black hole masses due to the pair-instability supernova process. These hierarchical mergers carry distinct spin…
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P. Abratenko, D. Andrade Aldana, Luciano Arellano et al. · 2025 · Nature
Abstract The existence of three distinct neutrino flavours, ν e , ν μ and ν τ , is a central tenet of the Standard Model of particle physics 1,2 . Quantum-mechanical interference can allow a neutrino of one initial flavour to be detected sometime later as a different flavour, a process called neutrino oscillation. Several anomalous observations inconsistent with this three-flavour picture have motivated the hypothesis that an additional neutrino state exists, which does not interact directly with matter, termed as ‘sterile’ neutrino, ν s (refs. 3–9 ). This includes anomalous observations from
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Alexandra Moroianu, Shivani Bhandari, Maria R. Drout et al. · 2025 · The Astrophysical Journal Letters
Abstract We report the milliarcsecond localization of a high (∼1379 pc cm −3 ) dispersion measure (DM) repeating fast radio burst (FRB), FRB 20190417A. Combining European VLBI Network detections of five repeat bursts, we confirm the FRB’s host to be a low-metallicity, star-forming dwarf galaxy at z = 0.12817, similar to the hosts of FRB 20121102A, FRB 20190520B, and FRB 20240114A. We also confirm that it is associated with a previously reported persistent radio source (PRS), which is compact on milliarcsecond scales. Visibility-domain model fitting constrains the transverse physical size of th
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M. Rossi, Stefania Salvadori, Á. Skúladóttir et al. · 2025 · The Astrophysical Journal
Abstract The elusive properties of the first (Population III or Pop III) stars can be indirectly unveiled by uncovering their true descendants. To this end, we exploit our data-calibrated model for the best-studied ultrafaint dwarf galaxy (UFD), Boötes I, which tracks the chemical evolution (from carbon to zinc) of individual stars from their formation to the present day. We explore the chemical imprint of Pop III supernovae (SNe), with different explosion energies and masses, showing that they leave distinct chemical signatures in their descendants. We find that UFDs are strongly affected by
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Zengyou He, Hao Liang, Zheng Chen et al. · 2020 · IEEE Transactions on Knowledge and Data Engineering
Community detection is a key data analysis problem across different fields. During the past decades, numerous algorithms have been proposed to address this issue. However, most work on community detection does not address the issue of…
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Lucie E. Rowland, Mauro Stefanon, R. J. Bouwens et al. · 2026 · Monthly Notices of the Royal Astronomical Society
ABSTRACT Metallicity is a crucial tracer of galaxy evolution, providing insights into gas accretion, star formation, and feedback. At high redshift, these processes reveal how early galaxies assembled and enriched their interstellar medium. In this work, we present rest-frame optical spectroscopy of 12 massive ($\log (M_*/\mathrm{{\rm M}_{\odot }})&gt;9$) galaxies at $z\sim 6$–8 from the Reionization Era Bright Emission Line Survey (REBELS) Atacama Large Millimetre/submillimetre Array (ALMA) large program, observed with the James Webb Space Telescope (JWST) NIRSpec integral field unit spec
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Eliza Neights, Eric Burns, Chris L. Fryer et al. · 2025 · Monthly Notices of the Royal Astronomical Society
ABSTRACT Gamma-ray bursts are the most luminous electromagnetic events in the Universe. Their prompt gamma-ray emission has typical durations between a fraction of a second and several minutes. A rare subset of these events have durations in excess of a thousand seconds, referred to as ultra-long gamma-ray bursts. Here, we report the discovery of the longest gamma-ray burst ever seen with a $\sim$25 000 s gamma-ray duration, GRB 250702B, and characterize this event using data from four instruments in the InterPlanetary Network and the Monitor of All-sky X-ray Image. We find a hard spectrum, su
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Yin-Jie Li, Yuan-Zhu Wang, Shao-Peng Tang et al. · 2025 · The Astrophysical Journal
Abstract The origin of the correlation between the effective spins ( χ eff ) and mass ratios ( q ) of LIGO–Virgo–KAGRA’s binary black holes (BBHs) is still an open question. Motivated by the recent identification of two subpopulations of the BBHs, in this work we investigate the potential χ eff – q correlation for each subpopulation. Surprisingly, the χ eff – q correlation either significantly weakens or disappears for the low-mass subpopulation if we introduce a second χ eff distribution for the high-mass subpopulation, which likely originates from hierarchical mergers. This suggests that the
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Junyao Li, Ming-Yang Zhuang, Yue Shen et al. · 2025 · The Astrophysical Journal
Abstract Kiloparsec-scale dual and offset active galactic nuclei (AGNs) are signposts of accreting supermassive black holes (SMBHs) triggered during late-stage galaxy mergers, offering crucial insights into the coevolution of SMBHs and galaxies. However, robustly confirmed systems at high redshift (e.g., z > 1) are scarce and biased toward the most luminous and unobscured systems. In this study, we systematically search for kiloparsec-scale (projected separation <15 kpc) dual and offset AGNs around 571 moderate-luminosity, X-ray-selected AGNs, including the obscured population, utilizing
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S. H. Suyu, Ana Acebrón, C. Grillo et al. · 2026 · Astronomy and Astrophysics
Robust mass modeling of strong-lensing galaxy clusters is crucial for studying cosmology and galaxy evolution. We present and compare seven mass models of the galaxy cluster MACS J0138−2155, constructed using six independent modeling software programs, including parametric and free-form approaches. By conducting a blind analysis where all the mass-modeling teams constructed their models independently without exchanging results, we quantified uncertainties arising from modeling software and assumptions. MACS J0138−2155 is unique as the only cluster found to strongly lens two supernovae (SNe), R
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R. Abbasi, M. Ackermann, J. Adams et al. · 2026 · The Astrophysical Journal Letters
Abstract Recently, IceCube reported neutrino emission from the Seyfert galaxy NGC 1068. Using 13.1 yr of IceCube data, we present a follow-up search for neutrino sources in the northern sky. NGC 1068 remains the most significant neutrino source among 110 preselected gamma-ray emitters while also being spatially compatible with the most significant location in the northern sky. Its energy spectrum is characterized by an unbroken power-law with spectral index γ = 3.4 ± 0.2. Consistent with previous results, the observed neutrino flux exceeds its gamma-ray counterpart by at least 2 orders of magn
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