Current date: 2026-09-16
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Datestamp limit: 2026-09-16 (0 days ago)
Created/updated limit: 2026-09-09 (7 days ago)
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Scoring abstracts
Number of records retrieved: 891
Keyword score statistics
score 11 -- 1 abstracts
score 7 -- 2 abstracts
score 6 -- 2 abstracts
score 5 -- 1 abstracts
score 4 -- 6 abstracts
score 3 -- 12 abstracts
score 2 -- 23 abstracts
in total -- 47 abstracts
Articles that appeared on 2026-09-16
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[abstract 1 / 47] Wow! (score: 11)
- Title: Impact of Equation of State on Black Hole Accretion Flows and Radiative PropertiesAuthors: Yun-Ming Zhu, Indu K. Dihingia, Yosuke Mizuno, Ziri Younsi, Christian M. Fromm,Comments: 21 pages, 20 figures, 0 table, accepted for publication in the ApJSubjects: astro-ph.HECreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Previous literature has documented that BLACK HOLE shadow images are mainly shaped by spacetime geometry and plasma microphysics governing accretion flows. However, the influence of equations of state (EoS) remains under-explored. In this paper, we quantify how different plasma microphysics prescriptions, specifically the choice of EoS and electron-heating models, affect flow thermodynamics and the corresponding synthetic black-hole images. We perform three-dimensional general-RELATIVISTIC MAGNETohydrodynamics (GRMHD) simulations using two constant-$γ$ ideal EoSs with $γ= 4/3$ and 5/3 and a temperature-dependent variable EoS (TM) in both accretion flow states: Standard And Normal Evolution (SANE) and Magnetically Arrested Disk (MAD) regimes. The dynamical models are post-processed with general-RELATIVISTIC radiative transfer (GRRT) calculations at 86GHz and 230GHz, employing thermal and hybrid $κ$ electron distribution functions for SYNCHROTRON radiation. We also compare the two-temperature electron heating prescription based on turbulent heating and MAGNETic RECONNECTion. The constant-$γ$ EoSs systematically overestimate or underestimate gas and electron temperatures across disk and JET regions, whereas the variable EoS provides a smoother trans-RELATIVISTIC interpolation between the two limiting regimes. These differences substantively impact the SYNCHROTRON emissivity, image morphology, and the amplitude of flux variability. In particular, the variable EoS exhibits systematically larger temporal variability than the constant-$γ$ models. These results demonstrate that adopting a physically self-consistent description of the EoS is essential for realistic modeling of accretion-flow thermodynamics and horizon-scale images like Event Horizon Telescope (EHT) observations.
[abstract 2 / 47] Wow! (score: 7) - Title: NOCTURNE. II. Extreme radio variability in the heart of early-stage ACTIVE GALACTIC NUCLEiAuthors: Emilia Järvelä, Patrizia Romano, Anne Lähteenmäki, Marco Berton,Comments: 5 pages, proceedings for the conference ZIHUAGN Redemption: central kpc region, Zihuatanejo, Gro., Mexico, October 27-31, 2025. Accepted for publication on Revista Mexicana de Astronomía y AstrofísicaSubjects: astro-ph.GACreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
We report the discovery of extreme 37 GHz radio variability in early-stage ACTIVE GALACTIC NUCLEi (AGN). Most of these sources belong to the class of narrow-line Seyfert 1 (NLS1) galaxies, which harbour fast-growing, low-mass supermassive BLACK HOLEs that accrete at high Eddington ratios. At 37 GHz, these extraordinary AGN exhibit amplitude variability of three to four orders of magnitude over timescales of a few days. Notably, despite several attempts, we have not detected RELATIVISTIC JETs in these sources, suggesting that this phenomenon may occur very close to the BLACK HOLE and may represent a new form of AGN variability. One of these sources, which flared at 37 GHz, was followed up with the Karl G. Jansky Very Large Array and SWIFT XRT/UVOT. Based on these observations, we estimated an e-folding timescale of mere hours, leading to variability brightness temperatures and variability Doppler factors that are extremely difficult to explain by an incoherent emitter. This suggests a possible detection of coherent emission from an AGN, although more observations will be needed to distinguish between alternative scenarios.
[abstract 3 / 47] Wow! (score: 7) - Title: Constraints on the central engine of merger-driven long GAMMA-RAY BURSTsAuthors: Muskan Yadav, Roberto Ricci, Paz Beniamini, Hira Waseem, Tatsuya Matsumoto, Simone Dichiara, Eleonora Troja,Comments: 15 pages, 6 figures, 4 tablesSubjects: astro-ph.HECreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Recent observations have identified a new class of long-duration GAMMA-RAY BURSTs (GRBs) likely produced by compact binary mergers. Using radio observations and lightcurve modelling, we investigate whether a MAGNETar remnant can power the long-lasting prompt emission observed in this merger-driven GRB sample. We derive constraints on the MAGNETars' rotational energy and MAGNETic-field strength, and assess whether the MAGNETar central-engine model is viable for the observed events. We conducted 2.1 GHz radio observations of seven nearby merger-driven GRBs ($z<0.25$) using the Australia Telescope Compact Array (ATCA), obtaining sensitive upper limits on late-time radio emission 520-6900 days post-burst. We modelled the expected radio light curves from MAGNETar-energized ejecta interacting with the circumburst medium and compared them to our observations. We separately tested the MAGNETar hypothesis against the extended gamma-ray emission using a fallback-accreting MAGNETar model. No radio counterpart is detected in any of the observed GRBs, with 3$σ$ flux density upper limits of 33-72 $μ$Jy at 2.1 GHz. Modelling the expected SYNCHROTRON emission from MAGNETar-energized ejecta interacting with the circumburst medium, we find that the radio non-detections remain compatible with energetic outflows in low-density environments. The analysis of the prompt gamma-ray emission provides complementary constraints on the spin period and MAGNETic field of the MAGNETar engine. Once fallback accretion and JET baryon-loading are considered, the parameter space is narrowly confined.
[abstract 4 / 47] Yes (score: 6) - Title: Jet Feedback and the Self-Regulated Growth of Black Holes Embedded in AGN DisksAuthors: Marguerite Epstein-Martin, Kung-Yi Su, Zoltan Haiman, Rosalba Perna,Comments: 24 pages, 12 figures, 1 table. Submitted to MNRAS. Comments welcomeSubjects: astro-ph.HE astro-ph.GACreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
Accretion disks in ACTIVE GALACTIC NUCLEi (AGN) are expected to host embedded stellar-mass BLACK HOLEs (BHs) whose gas capture rates can be highly super-Eddington. Without feedback, they would rapidly grow and deplete the disk, but at such high feeding rates, radiation is advected inward with the flow. We test whether the resulting accretion-powered JET and its shocked cocoon can (i) self-regulate the BH's growth rate and (ii) break out of the AGN disk. Using GIZMO, we perform three-dimensional simulations of a $10\,{\rm M}_\odot$ BH, embedded in dense AGN-disk gas, launching a particle-spawned JET whose mass flux scales with the accretion rate. We explore a range of JET velocities, ambient temperatures and densities, and three cooling regimes. We find that the JET-inflated cocoon stalls near the Bondi radius and maintains a modest aspect ratio and the self-regulated mass flux is determined by momentum balance at the Bondi radius. Cooling controls the mode of self-regulated accretion, from large-amplitude oscillation cycles at low metallicity to weak, quasi-steady modulation at solar metallicity. Scaling our results to outer disk conditions implies that mechanical feedback limits BH growth to within an order of magnitude of the Eddington rate -- largely preventing the overgrowth problem. Over the same disk region, the cocoon remains confined within the disk. In the inner disk, accretion onto the embedded BHs is limited by tidal shear rather than the Bondi radius, and our simulations no longer apply. Whether runaway growth and cocoon breakout remains possible in these inner regions needs further study.
[abstract 5 / 47] Yes (score: 6) - Title: Charging of rotating BLACK HOLEs: kinetic simulations of BLACK HOLE MAGNETospheresAuthors: Martin Kološ, Farukh Abdulkhamidov, Arman Tursunov, Jorge A. Rueda, Benoît Cerutti,Comments: Axisymmetric GRPIC simulations with the GRZeltron code plus an analytic flux-balance model; 14 pages, 5 figuresSubjects: gr-qc astro-ph.HECreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Whether a rotating BLACK HOLE (BH) immersed in an external MAGNETic field charges up to the Wald value $Q_{\rm W}=2aMB$, where $M$ and $a$ are the BH mass and spin parameter, and $B$ is the strength of the external field, is a long-standing open question in BH electrodynamics, with consequences for charge separation, particle acceleration and the structure of BH MAGNETospheres. We address it with axisymmetric general-RELATIVISTIC particle-in-cell simulations performed with GRZeltron, including self-consistent pair creation. For representative values of the BH spin, we evolve the same asymptotically uniform Wald field from two opposite initial horizon charges, $Q_{0}=0$ and $Q_{0}=Q_{\rm W}$, and track the accumulated charge through the BH horizon. We find that both branches relax within a few tens of gravitational times to the same saturated charge value. Thus, the equilibrium is a dynamical attractor of the kinetic MAGNETosphere rather than a memory of the initial data. The attractor lies well below $Q_{\rm W}$, at $ξ_{\rm eq}\equiv Q_{\rm eq}/Q_{\rm W}\approx 0.3$ for $a\lesssim0.7$, then falling almost to $ξ_{\rm eq}\approx0$ for large spins $a\approx1$. We derive an analytic expression for $ξ_{\rm eq}$ by requiring equal MAGNETic fluxes through the horizon associated with positive and negative charges, and find its spin dependence to be in agreement with the simulations. The charge state of an astrophysical BH is therefore driven by kinetic plasma processes, and the Wald charge is an upper bound, not a general equilibrium value. Since $ξ_{\rm eq}<1$, charging does not quench the horizon-infinity potential drop that powers energy-extraction processes such as the Blandford-Znajek mechanism.
[abstract 6 / 47] Yes (score: 5) - Title: Determination of the Angular Distributions of Dynamical and Emission Parameters of GRB Relativistic OutflowsAuthors: A. Panaitescu,Comments: to be published in the ApJ, 26 pages, 9 figuresSubjects: astro-ph.HECreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
A previously-developed analytical treatment of the "Larger-Angle Emission" model for GRBs and afterglows is further developed to include the effect of a fixed MAGNETic field orientation. This model, has the uncanny ability to unify the prompt and delayed emissions and to account easily for the entire diversity of SWIFT X-ray light-curves. The LAE model is applied to seven GRBs (060526, 060614, 060714, 060729, 061007, 061121, 100902, 130427A) with well-sampled 0.3 keV/10 keV SWIFT/XRT and optical light-curves, displaying well-monitored four phases (GRB, Tail, Plateau, post-Plateau), to illustrate its power and limitations and to determine its five fundamental parameters. The one-and-only Core parameter Gamma_c*theta_c is determined by the GRB and afterglow temporal milestones (i.e. by the dynamical range of the Tail and Plateau), and may have an universal value around 3.0, with narrower Cores (smaller theta_c) being more RELATIVISTIC (higher Gamma_c). Flat Plateaus require an Envelope angular structure close to Gamma(theta) ~ 1/theta^2. A MAGNETic field parallel to the direction of the RELATIVISTIC flow yields more curved prompt/GRB and delayed/afterglow light-curves than a perpendicular or isotropic field, with curvature $Δα$ defined as the difference between the flux asymptotic power-law decay indices at the beginning and end of each phase. The curvature Delta alpha_grb of the GRB light-curves arising from the uniform Core is set only by the B-field orientation, and a perpendicular or isotropic B-field is equally often found, but a parallel field is never identified for the Core. The curvature Delta alpha_ag of the afterglow light-curves from the power-law Envelope depends on B-orientation and three other parameters. The Envelope B-field orientation can be identified for only three afterglows, where a parallel B is found.
[abstract 7 / 47] Yes (score: 4) - Title: Induced Scattering of Fast Radio Bursts in Magnetar MagnetospheresAuthors: Rei Nishiura, Shoma F. Kamijima, Kunihito Ioka,Comments: 8 pages, 4 figures. Accepted to Physical Review DSubjects: astro-ph.HE physics.plasm-phCreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
We investigate induced Compton/Brillouin scattering of electroMAGNETic waves in MAGNETized electron and positron pair plasma by verifying kinetic theory with Particle-in-Cell simulations. Applying this to fast radio bursts (FRBs) in MAGNETar MAGNETospheres, we find that the scattering--although suppressed by the MAGNETic field--inevitably enters the linear growth stage before the incident wave amplitude becomes comparable to the background MAGNETic field during its outward propagation through the MAGNETosphere. The subsequent evolution bifurcates: full scattering occurs when the density exceeds a critical value, whereas below it the scattering saturates and the FRB can escape without substantial induced-scattering attenuation. This nonlinear saturation eases the tension with observations of compact emission regions and may explain the observed diversity, including the presence or absence of FRBs associated with X-ray bursts.
[abstract 8 / 47] Yes (score: 4) - Title: Resistive instabilities of current sheets in stratified plasmas with a gravitational fieldAuthors: Faisal Sayed, Anna Tenerani, Richard Fitzpatrick,Comments: 23 pages, 9 figures,Subjects: physics.plasm-ph physics.space-phCreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
Magnetic RECONNECTion can develop spontaneously via the tearing instability, often invoked to explain disruptive instabilities in fusion devices, solar flares, the generation of periodic density disturbances at the tip of helmet streamers, and flux transfer events at the Earth's dayside MAGNETopause. However, in many such environments the presence of gravity, MAGNETic field curvature or other forms of acceleration often result in situations of a heavy-over-light plasma in an effective gravitational field with an embedded current sheet. This paper studies the linear stability of a slab current sheet with respect to RECONNECTing modes in the presence of a density gradient under the effect of a constant gravitational acceleration. We show that the presence of stratification and gravity modify the properties of the tearing mode instability both in the case of favorable and unfavorable stratification. Favorable stratification suppresses RECONNECTion while unfavorable stratification strongly destabilizes the tearing mode. Furthermore, we show that the classical constant-ψ regime effectively does not exist, even for weak unfavorable stratification, for S>>1. Instead, the gravity-modified tearing progressively transitions into the G-mode, which is a gravity-driven RECONNECTing mode with a growth rate scaling as S^-1/3. As a consequence, unfavorable stratification only permits rapidly RECONNECTing modes.
[abstract 9 / 47] Yes (score: 4) - Title: Temporal Invariance Is an Illusion: Time-Dependent Influences of the Galactic Magnetic Field on UHECR ObservationsAuthors: Veronika Vašíčková, Leonel Morejón, Karl-Heinz Kampert,Comments: 13 pages, 8 figures excl. appendix, or 18 pages, 12 figures incl. appendixSubjects: astro-ph.HECreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Understanding the origin of the Ultra-High-Energy Cosmic Rays (UHECRs) requires explaining the features of their energy spectrum, mass composition, and arrival directions. Current modeling approaches neglect the time evolution of UHECR observables, a factor that is particularly important in the case of bursting UHECR sources. This study focuses on the influence of time delays caused by the galactic MAGNETic field (GMF) on the spectrum and arrival directions of UHECRs observed on Earth. Using CRPropa 3.2, we investigate the rigidity-dependence of the residence time of extragalactic COSMIC RAYs entering our Galaxy. We find that UHECRs entering the Milky Way can experience delays of hundreds of kiloyears relative to light, and we demonstrate that these delays significantly alter the UHECR observables. Notably, a cutoff emerges in the transient scenario within the rigidity range of $10^{18}-10^{19}$ V, which coincides with the spectral break observed in data. We find a progressive shift in composition favoring heavier nuclei, as well as a delay distribution that is correlated with GMF strength. This causes the particles to be less correlated with their initial direction the larger their delays. A dipole-like anisotropy develops over timescales of about $\sim$100 kyr in certain bursts scenarios. Our results provide an alternative explanation for the UHECR spectral cutoff that does not invoke limits on source acceleration. This could potentially revise existing constraints.
[abstract 10 / 47] Yes (score: 4) - Title: Evolution of the High-Energy Excess in SWIFT J1727.8-1613 during Its 2023 Flare StateAuthors: Xiao Fan, Bei You, Yi Long, Han He, Liang Chen,Comments: accepted to ApJSubjects: astro-ph.HECreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
We investigate the evolution of the high-energy excess in SWIFT J1727.8-1613 during its 2023 flare state using joint Insight-HXMT and INTEGRAL/ISGRI observations covering 2-500 keV. Fits to the broadband spectra with a model including thermal Comptonization and disk reflection leave systematic positive residuals above ~150 keV. Adding a power-law component improves the fits and yields photon indices of 2.08-2.61, demonstrating that the high-energy excess beyond the thermal Comptonization continuum is present throughout the flare state. We also show that all spectra can be well described by the hybrid Comptonization model eqpair, without requiring any additional high-energy component. The fitting results indicate that the energy supply to the electrons transitions from predominantly thermal heating to non-thermal acceleration, and that the electron injection spectrum steepens abruptly near the onset of the flare state. During this evolution, the radio spectral index changes from approximately zero to negative values, accompanied by the ejection of three transient JET knots. Based on this temporal association, we discuss a possible connection between the increase in non-thermal power indicated by our spectral analysis and the ejection of the transient JET.
[abstract 11 / 47] Yes (score: 4) - Title: Formation of Merging Black Hole Binaries Inside Massive AGN StarsAuthors: Sizheng Ma, Douglas N. C. Lin, David A. Velasco-Romero,Comments:Subjects: astro-ph.HE astro-ph.GA astro-ph.SR gr-qcCreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
Stars embedded in the disks of ACTIVE GALACTIC NUCLEi (AGN) can grow to hundreds of solar masses, and the same disks are expected to host a population of stellar-mass BLACK HOLEs. A star may therefore capture passing BLACK HOLEs, turning its interior into a potential factory for forming compact binary BLACK HOLE systems and, ultimately, for the gravitational-wave events seen by our detectors. We test how readily this channel operates using three-dimensional hydrodynamic simulations of BLACK HOLE--star encounters. As a proof of principle, we adopt a star-to-black-hole mass ratio of $34\!:\!1$, and find that the capture does not disrupt the structure of the star: it heats the star by $10$--$30\%$, and the star loses only $\lesssim1\%$ of its mass throughout. The captured BLACK HOLE loses its orbital angular momentum rapidly to dynamical friction, sinking to the stellar center within a stellar dynamical time $\lesssim10^{4}\,$s. If the star already harbors a BLACK HOLE at its center, the two form a bound binary whose gravitational-wave coalescence time falls below $10^{4}\,$yr. Depending on the geometry and speed of the encounter, the resulting orbit may be nearly circular or retain substantial eccentricity. Our calculations confirm that BLACK HOLE--star encounters in AGN disks are indeed a viable channel for assembling stellar-mass BLACK HOLE binaries and supplying sources for gravitational-wave detectors.
[abstract 12 / 47] Yes (score: 4) - Title: An ALMA Band 7 survey of SDSS/Herschel QUASARs in Stripe 82: II. The nature of FIR-bright QUASARsAuthors: Evanthia Hatziminaoglou, Hugo Messias, Duncan Farrah, Anna Feltre, Dennis Koopmans, Ismael Perez-Fournon, Rhimon Souza, Lingyu Wang,Comments: Accepted for publication in A&A, 10 pages, 7 figuresSubjects: astro-ph.GACreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
We investigate the STAR FORMATION properties and ultraviolet (UV)/optical spectral characteristics of 142 far-infrared (FIR)-bright QUASARs at redshifts 1 < z < 4 to probe supermassive BLACK HOLE (SMBH) and host galaxy co-evolution. By combining multi-wavelength observations with high-resolution ALMA submillimeter (submm) data, we overcome source confusion and robustly constrain STAR FORMATION rates (SFRs). The inclusion of ALMA data to the Spectral Energy Distribution fitting reduces SFR estimates by ~20% for QUASARs with single submm counterparts and by a factor >2 for FIR-blended multi-component systems, while reducing FIR luminosity uncertainties by ~18%. The revised host SFRs span 500 and 3000 solar masses per year (median 1080 solar masses per year), confirming these systems are extreme starbursts. The very shallow positive correlation between starburst and accretion luminosities suggests that SMBH accretion and STAR FORMATION in the host are not coupled on the timescales probed by the observations. Compared to the general population of FIR-faint QUASARs, FIR-bright sources have a factor of three higher detection rates at 1.4 GHz, predominantly following the FIR-radio correlation, and reduced CIV and Lya equivalent widths with unaffected MgII, suggesting AGN-driven winds that leave MgII relatively unaffected. Together, these results place FIR-bright QUASARs in a brief transitional phase, bridging heavily obscured "blowout" galaxies and optically unobscured blue QUASARs, where bulge assembly and SMBH growth peak simultaneously during ongoing stellar assembly.
[abstract 13 / 47] (score: 3) - Title: FastQSL 2: A Comprehensive Toolkit for Magnetic Connectivity AnalysisAuthors: Jun Chen, Thomas Wiegelmann, Li Feng, Chaowei Jiang, Rui Liu,Comments: 18 pages, 6 figuresSubjects: astro-ph.SRCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
We present a new version of FastQSL for locating quasi-separatrix layers (QSLs) -- regions characterized by strong MAGNETic connectivity gradients, preferential current buildup, and subsequent MAGNETic RECONNECTion. This version now supports spherical coordinates, utilizing a second spherical coordinate system for tracing MAGNETic field lines around the polar regions. This approach completely resolves the singularity problem at the two poles. Furthermore, our code accommodates arbitrary mesh shapes for output, can provide both MAGNETic field and electric current density on the mesh, and can save the traced MAGNETic field lines. We suggest using $Q_\mathrm{local}$ calculated through a localized mapping to locate (quasi-)separators. By quickly and accurately outputting the footpoint coordinates of MAGNETic field lines, FastQSL can be used to derive the two key parameters used for modeling solar wind speed and slip-squashing factors for the case of zero boundary flow. Compared with the first version, FastQSL 2 achieves significant improvements in terms of application scope.
[abstract 14 / 47] (score: 3) - Title: Traversing the Galactic Centre in space and timeAuthors: Michal Zajaček, Bożena Czerny, Martin Mondek, Samik Mitra, Matúš Labaj, Tomáš Ondro, Jan Janík, Jiří Dušek,Comments: 5 pages, 1 figure, concise meeting report of the Galactic Center workshop 2026 (IAU Symposium 405, https://gc2026.muni.cz/); accepted version, published in Nature AstronomySubjects: astro-ph.GA astro-ph.HECreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
The Galactic Center is often identified with its central supermassive BLACK HOLE, Sgr A*. Yet the BLACK HOLE governs gravitationally only the innermost few parsecs of the Milky Way, while the surrounding Nuclear Star Cluster, Nuclear Stellar Disc and Central Molecular Zone (CMZ) shape the dynamics of stars and gas on progressively larger scales. Understanding how these components interact is essential not only for reconstructing the history of our own Galaxy, but also for interpreting galactic nuclei more generally.
[abstract 15 / 47] (score: 3) - Title: Low-Temperature Co-Fired Ceramics for a Sustainable Planar Plasma Jet with Homogeneous Plasma in Large Treatment Areas for Biomedical ApplicationsAuthors: Ivan Gomez Ho, Hua-Lin Chen, Cheng-Han Tsai, Jong-Shinn Wu, Yun-Chien Cheng,Comments: 31 pages, 15 figures, Updated the affiliation of ; no changes were made to the scientific contentSubjects: physics.plasm-phCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
This study presents a portable planar argon-based plasma JET designed for large-area biomedical applications, with an emphasis on uniform discharge, stability, and safety. The device incorporates interchangeable rear and side inlet gas adapters with restriction plates and channels to equalize gas flow, while electrodes are encapsulated in low-temperature co-fired ceramics to reduce degradation and arcing during repeated operation. Flow simulations were conducted for multiple channel configurations to ensure laminar gas distribution and uniform plasma generation. Device performance and safety were evaluated using the kinPen MED as a reference standard. Electrical characteristics, optical emission, discharge uniformity, temperature, gas velocity, ozone generation, UV irradiance, and leakage current were systematically measured. The plasma exhibited stable voltage, current, and power after an initial warm-up period. Temperatures stabilized within minutes, with the rear-inlet configuration demonstrating lower operating temperatures due to higher outlet gas velocity. Ozone levels remained below established safety limits, while UV exposure constrained allowable treatment times. Leakage current decreased with increasing distance and approached safety thresholds at short separations. These results demonstrate that the proposed planar plasma JET provides stable, uniform plasma delivery while meeting key safety requirements, supporting its potential for clinical and biomedical use.
[abstract 16 / 47] (score: 3) - Title: The NOvA Test Beam ExperimentAuthors: NOvA Collaboration, S. Abubakar, M. A. Acero, B. Acharya, P. Adamson, N. Anfimov, A. Antoshkinaf, E. Arrieta-Diaz, L. Asquith, A. Aurisano, N. Balashov, P. Baldi, B. A. Bambah, E. F. Bannister, A. Barros, J. Barrow, A. Bat, T. J. C. Bezerra, V. Bhatnagar, B. Bhuyan, J. Bian, S. Block, A. C. Booth, B. Brahma, C. Bromberg, N. Buchanan, J. Burns, A. Butkevich, T. J. Carroll, E. Catano-Mur, J. P. Cesar, C. Chang, S. Chaudhary, H. Chen, S. Choate, B. C. Choudhary, O. T. K. Chow, A. Christensen, M. F. Cicala, T. E. Coan, T. Contreras, A. Cooleybeck, L. Cremonesi, G. S. Davies, P. F. Derwent, K. Dever, Z. Djurcic, K. Dobbs, D. Dueñas Tonguino, E. C. Dukes, A. Dye, R. Ehrlich, E. Ewart, P. Filip, W. Flanagan, M. J. Frank, H. R. Gallagher, F. Gao, A. Giri, R. A. Gomes, M. C. Goodman, R. Group, A. Gusmão, A. Habig, F. Hakl, J. Hartnell, R. Hatcher, J. M. Hays, M. He, A. Heggestuen, K. Heller, V Hewes, A. Himmel, T. Horoho, J. Huang, X. Huang, T. Huynh, A. Ivanova, C. Joe, K. Kaess, I. Kakorin, A. Kalitkina, D. M. Kaplan, A. Khanam, B. Kirezli, J. Kleykamp, O. Klimov, L. W. Koerner, L. Kolupaeva, R. Kralik, G. Kufatty, A. Kumar, C. D. Kuruppu, V. Kus, T. Lackey, K. Lang, A. Lister, J. Liu, J. A. Lock, S. Magill, R. C. Mandujano, W. A. Mann, M. T. Manoharan, M. Manrique Plata, A. Marathe, M. L. Marshak, M. Martinez-Casales, V. Matveev, T. McGuire, A. Medcalf, A. Medhi, B. Mehta, M. D. Messier, H. Meyer, T. Miao, S. Mishra, R. Mohanta, A. Moren, A. Morozova, W. Mu, L. Mualem, M. Muether, C. Murthy, D. Myers, J. Nachtman, D. Naples, J. K. Nelson, O. Neogi, R. Nichol, E. Niner, G. Nissan, M. Nixon, A. Norman, A. Norrick, D. Northacker, H. Oh, A. Olshevskiy, T. Olson, Y. Onel, A. Pal, J. Paley, L. Panda, R. B. Patterson, G. Pawloski, R. Petti, D. D. Phan, R. K. Pradhan, L. R. Prais, S. Puhan, J. Rabaey, A. Rafique, M. Rajaoalisoa, B. Ramson, B. Rebel, C. Reynolds, P. Roy, D. Sagar, O. Samoylov, M. C. Sanchez, S. Sãnchez Falero, P. Shanahan, P. Sharma, A. Sheshukov, S. Shukla, I. Singh, P. Singh, V. Singh, P. Snopok, E. Sobimpe, N. Solomey, A. Sousa, K. Soustruznik, M. Strait, C. Sullivan, L. Suter, A. Sutton, K. Sutton, S. K. Swain, A. Sztuc, N. Talukdar, P. Tas, J. Thomas, E. Tiras, M. Titus, Y. Torun, D. Tran, J. Trokan-Tenorio, J. Urheim, B. Utt, P. Vahle, Z. Vallari, K. J. Vockerodt, A. V. Waldron, M. Wallbank, B. Wang, C. Weber, M. Wetstein, D. Whittington, D. A. Wickremasinghe, J. Wolcott, W. Wu, Y. Xiao, B. Yaeggy, A. Yahaya, A. Yallappa Dombara, A. Yankelevich, K. Yonehara, S. Zadorozhnyy, J. Zalesak, L. Zhao, R. Zwaska,Comments:Subjects: hep-exCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
NOvA is a long-baseline neutrino oscillation experiment designed to study the neutrino mixing parameters, mass ordering, and CP violation in the lepton sector. A key component of the success of the experiment is a robust understanding of the systematic uncertainties associated with detector response and calibration. To address this, NOvA deployed a Test Beam experiment at the FERMIlab Test Beam Facility, which collected data from April 2019 through July 2022. The NOvA Test Beam experiment used a 30-ton segmented liquid scintillator detector functionally identical to the NOvA Near and Far Detectors to analyze tagged particles produced from p-Cu collisions, with instrumentation capable of selecting and identifying electrons, muons, pions, kaons, and protons with momentum ranging from 0.4-1.5GeV/c. Analysis of the collected data provides a better understanding of the largest systematic uncertainties impacting NOvA's analyses, which include the detector response, energy calibration, and hadronic and electroMAGNETic energy resolutions.
[abstract 17 / 47] (score: 3) - Title: Exploring the dynamics of the Coma galaxy cluster by mapping its X-ray emission line profiles with XRISMAuthors: Kosei Sakai, Kazuhiro Nakazawa, Maxim Markevitch, Dominique Eckert, Yuichiro Ezoe, Yuto Ichinohe, Richard Kelley, Richard Mushotzky, Nobuhiro Okabe, Yuki Omiya, Naomi Ota, Cicely Potter, Andrew Szymkowiak, Shunsuke Torii, Nhut Truong, Ayşegül Tümer, Yuusuke Uchida, Dan Wik, Irina Zhuravleva, John ZuHone,Comments: 9 pages, 5 figure, PASJ acceptedSubjects: astro-ph.HECreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
The intracluster medium (ICM) in merging galaxy clusters exhibits turbulence and bulk flows. Unraveling these components is crucial not only for elucidating the geometry of the cluster mergers, but also for understanding the physics of MAGNETic field amplification and RELATIVISTIC particle acceleration. XRISM/Resolve data for two $3'\times3'$ fields in the core of the Coma cluster reveales that the ICM in the central field moves with $Δcz = -430$~km~s$^{-1}$ relative to the cluster galaxy average, while that in the southern field moves with $Δcz = -730$~km~s$^{-1}$ (see \cite{2025ApJ...985L..20X}, hereinafter ``Paper I''). In this paper, we perform a more detailed analysis of these data sets to search for non-Gaussian features in the Fe-K line complex profiles. In the spectra from the northwest (NW) quadrant of the central field, in addition to the main and redshifted ICM components ($Δcz = -40$ km s$^{-1}$) reported in Paper I, we find evidence of another, blueshifted component, moving with $Δcz = -1250$ km s$^{-1}$. For a systematic search for other significant velocity components, we perform a bias-free 3 eV step multi-component fit to the Resolve full-array spectra from the central and southern fields. This search uncovers another redshifted component in the southern field, moving with $Δcz \sim +1230$ km s$^{-1}$. We estimate the energy densities of the ICM turbulence and bulk motion to be similar to each other and several times greater than the energy density of the cluster's $B\sim 5~μ$G MAGNETic field.
[abstract 18 / 47] (score: 3) - Title: A Dark-matter Origin of Little Red Dots: Early Seeding and Super-Bondi AccretionAuthors: Hua-Peng Gu, Fangzhou Jiang, Xian Chen, Ran Li, Zi-Xiang Jia,Comments: 22 pages, 7 figures, submittedSubjects: astro-ph.CO astro-ph.GA astro-ph.HECreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
The "Little red dots" (LRDs) are a population of accreting supermassive BLACK HOLEs (SMBHs) in the early Universe which often exhibit undermassive or even undetectable stellar hosts. Their early emergence, high space density, and extremely large black-hole-to-stellar mass ratios pose a serious challenge to conventional seeding scenarios that rely on baryon for both the formation and growth of BLACK HOLEs. Here we demonstrate that the above anomalies can be naturally resolved if DARK MATTER is self-interacting. We apply a fully RELATIVISTIC, non-equilibrium halo-evolution model, first developed in our earlier work, to trace the complete gravothermal evolution of self-interacting DARK MATTER (SIDM) halos, from the initial collapse into BH seeds to the subsequent accretion of DARK MATTER. We find that in highly concentrated halos assembled before reionization, gravothermal collapse efficiently produces stellar-mass black-hole seeds within a few hundred million years. Remarkably, and contrary to standard expectations for dark-matter accretion, heat conduction in SIDM then sustains a prolonged super-Bondi inflow that drives these seeds to supermassive scale by the LRD epoch, without baryonic assistance. The halo conditions required for completing these processes, together with the probability of avoiding major mergers that disrupt gravothermal evolution, result in an SMBH population consistent with the observed abundance and redshift distribution of LRDs. Our findings establish a pathway in which SMBHs are seeded and assembled primarily from DARK MATTER, well before substantial galaxies form around them, thereby offering both a compelling physical explanation for LRDs and a new observational probe of dark-matter microphysics.
[abstract 19 / 47] (score: 3) - Title: The third law of BLACK HOLE thermodynamics: Quantum versus classical considerationsAuthors: Shahar Hod, Tsvi Piran,Comments: 4 pagesSubjects: gr-qcCreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
Kehle and Unger have recently shown that, under suitable conditions, a massless charged classical scalar field can produce an extremal BLACK HOLE in finite time. This result appears to violate the third law of thermodynamics (TLT), since extremal BLACK HOLEs have zero temperature. However, because the TLT is intrinsically a quantum principle, a self-consistent analysis of this problem must account for quantum effects. In particular, we point out that the electric field of the system may spontaneously polarize the vacuum, thereby creating massless charged pairs that will discharge the BLACK HOLE. This mechanism guarantees the {\it quantum} validity of the TLT in the regime $|eQ|\geq\hbar/2$ (here ${Q,e}$ denote, respectively, the electric charges of the BLACK HOLE and the scalar field). This leaves open the question of what happens for lower values of $|eQ|/\hbar$. Recently, Schneider derived a classical bound showing that extremal BLACK HOLEs cannot be formed à la Kehle-Unger in the small-charge regime $|eQ|\leq\hbar/3$. His analysis leaves open the possibility that a stronger bound may exist. We conjecture here that this bound can indeed be strengthened such that classical considerations would prevent extremal (zero-temperature) charged Reissner-Nordström BLACK HOLEs from forming dynamically in the regime $|eQ|<\hbar/2$, where quantum POLARIZATION effects are too weak to preserve the validity of the TLT.
[abstract 20 / 47] (score: 3) - Title: Analog Gravity in Magneto-Viscous Fluids: Enhanced Analog Hawking Temperature in Accretion DisksAuthors: Aliv Sahoo, Mayank Pathak, Banibrata Mukhopadhyay,Comments: 28 pages including 7 figures (20 png files). Comments are welcome!Subjects: gr-qcCreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
We present a three-dimensional visco-MAGNEToacoustic framework for analog gravity in MAGNETohydrodynamic (MHD) flows. While standard fluid dissipation typically breaks the Lorentzian signature of acoustic metrics, we demonstrate that evaluating wave perturbations in the eikonal limit alongside the Shakura-Sunyaev $α$-viscosity prescription preserves a well-defined effective spacetime geometry for the fast MAGNEToacoustic mode. The slow-MAGNEToacoustic mode and Alfvén mode do not admit a non-degenerate metric. To investigate analog horizon thermodynamics, we utilize astrophysical accretion disks as background media, specifically modeling numerical MAGNETized advective accretion flows around rotating BLACK HOLEs and analytical advection-dominated inflow-outflow solutions (ADIOS). Standard self-similar ADIOS models strictly enforce a constant Mach number, precluding horizon formation. We therefore introduce a MAGNETic field perturbation that breaks self-similarity, generates a dynamic Mach number, and enables the formation of a visco-MAGNEToacoustic horizon. By evaluating the spontaneous phonon emission at these horizons, we reveal that the analog Hawking temperature is highly sensitive to the MAGNETic field topology; the spatial orientation of the background MAGNETic gradients dictates whether the Hawking radiation is amplified or suppressed. Furthermore, we find that increasing the viscosity parameter leads to a monotonic increase in the analog Hawking temperature.
[abstract 21 / 47] (score: 3) - Title: Dynamic Accretion Disk-Corona Connection and Broad Fe K$α$ Variability in Mrk 766 Revealed by Time-Resolved High Resolution X-Ray Spectroscopic AnalysisAuthors: Ayon Mondal, Tathagata Saha, Arijit Sar, Ritaban Chatterjee,Comments: Manuscript accepted for publication in The Astrophysical Journal. (20 pages, 9 figures, 2 tables)Subjects: astro-ph.HECreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
We present a multi-epoch, primarily X-ray study of the narrow-line Seyfert 1 (NLSy1) galaxy Mrk~766 by combining archival \textit{XMM-Newton} observations spanning nearly two decades together with a \textit{XRISM} observation obtained during its Performance Verification Phase. We analyzed the absorption and emission features in the soft X-ray spectra from RGS and EPIC-pn data, revealing a stratified multi-phase potentially ionised absorber with a column density varying at a timescale of $\sim$1 day. The covering fraction shows positive correlation with the continuum flux, however with significant intrinsic scatter, between the epochs. Mrk~766 exhibits a multi-component Fe\,K$α$ emission line as revealed by fits to the \textit{XRISM} data. A quasi-phenomenological model comprising a torus and a broad \textit{diskline} component distinguishes the two components and constrains the inner radius of the potential broad line emitting disk substructure between $R_{in}=40-60\,r_{\rm g}$. Analysis of multiple epochs of the Fe K$α$ complex across \textit{XMM-Newton} observations reveals that the broad component tracks the continuum flux closely and effectively reflects the trend with respect to the continuum. The narrow component is consistent with a distant emitter, potentially the torus. Quasi-simultaneous monitoring with \textit{SWIFT}-XRT and UVOT further indicates UV emission lagging the X-rays by $5.9^{+4.1}_{-5.7}$ hours, consistent with disk reprocessing of coronal X-ray fluctuations, and corresponds to a light travel distance of up to $10^{3}\,r_{\rm g}$. Overall, our analysis maps the extent of the dynamically evolving absorber, the iron line emitter, and the accretion disk in this highly accreting NLSy1 system.
[abstract 22 / 47] (score: 3) - Title: Radiation Pressure Instability-Driven Variability of Line-Driven Disk Winds in AGNs: Connection to Periodic Luminosity Variations and UFO AppearanceAuthors: Yutaro Kuroda, Ken Ohsuga, Mariko Nomura, Kenya Watarai,Comments: 11 pages, 7 figures, 2 tables, accepted for publication in PASJSubjects: astro-ph.HECreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
We investigated the temporal variability of line-driven disk winds induced by radiation pressure instability in accretion disks surrounding supermassive BLACK HOLEs. This is the first study to self-consistently couple one-dimensional hydrodynamic simulations of accretion disks with two-dimensional radiation hydrodynamic simulations of line-driven winds and to analyze their time-dependent evolution. Our results show that periodic luminosity oscillations caused by radiation pressure instability lead to corresponding changes in both the mass outflow rate and the covering factor of gas expected to be observed as ultra-fast outflows (UFOs), with a delay comparable to the viscous timescale around the wind base. The viewing angles from which UFOs are expected to be observed also change with time. Our results therefore imply that, depending on the viewing angle, UFOs may not be detected even during high-luminosity states, whereas they may be detected even at lower luminosities. These findings are consistent with observations showing that UFOs are not always detected at high luminosities and can sometimes be detected even at lower luminosities. For a BLACK HOLE mass of $10^{7.4}M_\odot$, a mass accretion rate of $1.3L_{\rm Edd}/c^2$ at a radius of about 100 Schwarzschild radii, a viscosity parameter of $α=0.1$, and a viscosity prescription parameter of $μ=0.45$, the mass outflow rate shows a delay of approximately 2--5 yr relative to the luminosity variation, and the covering factor consequently reaches a maximum of $\sim 30\%$ from the high-luminosity phase through the declining phase. Our results suggest that the intermittent detection of UFOs in luminosity-variable AGNs can be explained by radiation pressure instability driven variability of the line-driven disk winds.
[abstract 23 / 47] (score: 3) - Title: Ionization Profile Monitors for the IOTA Storage Ring at FERMIlabAuthors: R. Thurman-Keup, N. Banerjee, M. Bressler, K. Carlson, D. Edstrom, B. Fellenz, M. Mwaniki, H. Piekarz, A. Romanov, A. Semenov, V. Shiltsev,Comments: 15th International Beam Instrumentation Conference (IBIC2026)Subjects: physics.acc-phCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Ionization profile monitors (IPM) are used in many accelerator laboratories around the world for non-destructive profile measurements of high-energy particle beams. They have been used in nearly all the SYNCHROTRONs built at FERMIlab and are presently used in the Main Injector (MI), Recycler (RR), and Booster. This paper will present the current status of the design of a new pair of IPMs to be installed in the Integrable Optics Test Accelerator (IOTA), an experimental proton storage ring with a beam energy of 2.5 MeV. The design incorporates aspects of several IPMs previously or currently used at FNAL. Similar to the Booster IPM, ions are collected rather than electrons, thus requiring no external MAGNETic field. To increase the signal, each IPM uses two microchannel plates in the chevron configuration as is done in the MI/RR IPMs, and due to the ring's ultrahigh vacuum conditions, the local vacuum pressure is increased with a calibrated leak, akin to the former Tevatron IPMs, to increase the ionization yield per bunch. Data acquisition includes upgraded preamplifiers and leveraging of the digitizer design of the beam position monitor system already in use at IOTA. In addition to the mechanical and electronic designs, simulation results of the effects of the electric fields and injected gas on the circulating beam will also be presented.
[abstract 24 / 47] (score: 3) - Title: X-ray to Mid-IR Spectral Energy Distributions: A Catalog of X-ray Selected AGNs in the XMM-COSMOS SurveyAuthors: Şeyda Şen, Eda Sonbas, Ece Kilerci, Hasan Avdan, Kalvir S. Dhuga, Ersin Göğüş, W. N. Brandt,Comments: accepted for publication in ApJSSubjects: astro-ph.HE astro-ph.GACreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
We present a component-resolved analysis of the IR--X-ray connection in a sample of 104 spectroscopically confirmed Type~1 AGN. By combining \xmm, \swift/UVOT, and new high--angular resolution \jwst/NIRCam imaging for a subset of the sources, we constructed detailed SEDs in which the IR emission was explicitly decomposed into accretion-disk, torus, and polar-dust components. This approach enables us to isolate the intrinsic AGN-IR luminosities with minimal host-galaxy contamination, providing a clean assessment of the physical relationship between the accretion flow, circumnuclear dust, and the X-ray corona. By incorporating JWST/NIRCam observations into our SED decomposition, we significantly reduce host-galaxy contamination and isolate the nuclear infrared emission with greater fidelity, particularly at near-infrared (NIR) wavelengths. This improvement is most apparent at 1 $μ\mathrm{m}$, where sources with JWST coverage exhibit a markedly steeper relation between $ν$L$_ν$ (2 keV) and the NIR luminosity than those without JWST data. This behavior is naturally explained by starlight dilution, whereby host-galaxy emission dominates lower-resolution measurements.
[abstract 25 / 47] (score: 2) - Title: Mixing-induced thermal instabilities and coronal condensationsAuthors: B. Snow, A. Hillier,Comments: Accepted for MNRASSubjects: astro-ph.SRCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Cool, dense material is frequently observed to permeate the hot, tenuous solar corona in the form of prominences, spicules and coronal rain. Both the cool material and surrounding corona exist at temperatures that are effectively thermally stable, in that their local radiative losses occur on relatively long timescales compared to the dynamics. However, as the solar atmosphere evolves, driving mixing between the condensations and surrounding hot material, intermediate temperatures form, which can become subject to highly efficient radiative losses. The thermal energy lost due to radiation can far exceed the turbulent heating thus the system undergoes mixing-induced cooling. Here, a 3D radiative MHD simulation is performed of the shear-driven Kelvin-Helmholtz Instability (KHI) occurring between a cool condensation and the hot solar corona. During the evolution, thermal instabilities form naturally within the mixing layer, and grow with time to produce long, narrow structures that extend perpendicular to the MAGNETic field. The thermal instabilities form self-consistently within the mixing layer as small isolated events, and are then stretched by the background flows to create long structures in relatively narrow planes. The turbulent flows agitate the condensations and cause them to fragment, creating smaller localised clumps of cool, dense (prominence-like) material that can merge and further fragment. In the presented simulation, the thermal instabilities act to replenish the cool, dense material lost due to mixing, with the total mass of cool material being approximately constant through time. By analysing the thermal energy loss due to optically-thin radiation, thermal instabilities are found to account for 15-20\% of all radiative losses in the turbulent plasma.
[abstract 26 / 47] (score: 2) - Title: Survival of ultraheavy nuclei in astrophysical sources: applications to protoMAGNETar outflowsAuthors: Nick Ekanger, Mukul Bhattacharya, Kohta Murase, Shunsaku Horiuchi,Comments: 14 pages, 5 figures, 1 table. This matches the version published in PRDSubjects: astro-ph.HE hep-ph nucl-thCreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
Outflows of rapidly rotating protoMAGNETars have been considered as attractive sites for the synthesis of nuclei heavier than iron, but the question remains whether these nuclei are able to survive against photodisintegration as they make their way out of their formation environments. In this work, we present new analytic fitting formulae for the photodisintegration cross sections applicable to heavy nuclei beyond iron. We confirm that the results from the TALYS simulations are consistent with the theory of the giant dipole resonance, and apply the obtained new formulae to investigate whether ultraheavy nuclei entrained in protoMAGNETar outflows can be disintegrated by thermal and nonthermal photons before leaving the stellar envelope. We explore two outflow models: a spherical wind model and a JETted outflow model. For nuclei accelerated to the bulk speed of these outflows, their survival depends on the model and engine properties. For spherical winds, nuclei may survive for the first $\sim100\,{\rm s}$ post-core collapse, but as the wind Lorentz factor increases, the photodisintegration optical depth sharply rises and nuclei may no longer survive. For the JETted outflows arising from progenitors surrounded with stellar envelopes, nuclei can only survive before the JET breakout time in cases where the central engine has high spin-down energy, that is, with a high MAGNETic field strength and shorter spin period. In progenitors with more extended envelopes, the JET break out time is much longer, allowing for nonthermal photons to readily photodisintegrate nuclei in high spin-down energy cases. These results also outline some of the necessary, but not yet sufficient, conditions to source ultrahigh-energy cosmic-ray nuclei.
[abstract 27 / 47] (score: 2) - Title: Non-Schwarzschild BLACK HOLEs sourced by scalar-vector fieldsAuthors: Manuel Gonzalez-Espinoza, Y. Gómez-Leyton, Z. Stuchlik, Francisco Tello-Ortiz,Comments:Subjects: gr-qcCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
In this work, we construct a static and spherically symmetric BLACK HOLE solution sourced by a nonlinear scalar-vector sector within the framework of the Minimal Geometric Deformation (MGD) approach. Starting from a scalar-vector gravity theory in which the vector field is described by nonlinear electrodynamics, the gravitational field equations are integrated to obtain a non-Schwarzschild geometry. We show that the resulting family of solutions naturally splits into two BLACK HOLE branches with distinct physical properties. While one branch satisfies the odd- and even-parity stability criteria, it violates the weak energy condition outside the event horizon. Conversely, the complementary branch exhibits a more satisfactory effective matter sector, admitting a real scalar-field reconstruction and a regular nonlinear electroMAGNETic coupling, although it does not satisfy the odd-parity stability criterion. The causal structure and stability properties of both BLACK HOLE branches are analyzed and compared, whereas the matter reconstruction, geodesic motion and thermodynamic properties are investigated for the branch exhibiting the most satisfactory effective matter sector. These results reveal the rich structure of the MGD solution space and illustrate the interplay between dynamical stability, energy conditions and causal structure.
[abstract 28 / 47] (score: 2) - Title: Time-dependent cosmic-ray escape from wind bubbles: hard spectra formationAuthors: Lukas Merten, Sophie Aerdker, Enrico Peretti,Comments: accepted for publication in ApJSubjects: astro-ph.HECreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Overview: Wind-driven bubbles are dynamic systems that can accelerate COSMIC RAYs, depending on their physical properties, up to very high energies. We investigate how a time-dependent description of the particle transport may impact the escaping cosmic-ray flux. Model: The wind bubble system is modeled as spherically symmetric. Cosmic rays are continuously injected at the position of the termination shock and propagate through advection and diffusion until the escape at the time-dependent position of the forward shock, which is treated as a free escape boundary. Methods: The one-dimensional spherical time-dependent transport equation is solved by transforming it into the corresponding set of stochastic differential equations, and integrated with a modified version of the open source cosmic-ray propagation framework CRPropa. Results: We find that, during the wind driven phase, the downstream escaping spectra from wind bubbles can be harder than $\sim E^{-2}$, the conventional expectation from diffusive shock acceleration. Depending on the turbulence model the initial energy spectrum can be significantly suppressed at lowest energies, which could be an observable feature to distinguish between different turbulence realizations. This effect could lead to an efficient confinement of low energy particles, potentially leading to observable implication in terms of multi-messenger radiation and cosmic-ray accumulated grammage within the bubble.
[abstract 29 / 47] (score: 2) - Title: Thresholdless IBW Emission and Alpha-to-Thermal-Ion Energy Channeling via Pole Resonance of Fusion-Product IonsAuthors: Hong Qin, Nathaniel J. Fisch,Comments: 8 pages, 4 figuresSubjects: physics.plasm-phCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Fusion reactions can release a substantial fraction, and in aneutronic reactions nearly all, of their energy as the kinetic energy of fusion-product ions. In MAGNETized plasmas, these energetic ions can form ring distributions in velocity space. Such distributions can drive Dory-Guest-Harris (DGH) electrostatic instabilities, but these self-instabilities require a finite energetic-ion density and can be stabilized by a thermal background. We show that the same background can instead enable a distinct instability mechanism: a cyclotron pole of the minority energetic-ion susceptibility destabilizes a stable ion Bernstein wave (IBW) eigenmode. When the energetic-ion harmonic is distinct from the thermal-ion harmonics, exact root-pole resonance is thresholdless in the ideal collisionless limit. A species-resolved power balance shows that the energetic ions supply the free energy while the thermal plasma receives it. In the LAPD proton--alpha example, $99.96\%$ of the alpha-particle power loss enters the coherent proton response. This self-excited, ion-directed transfer provides a possible linear building block for alpha-particle energy channeling in proton-Boron11 fusion.
[abstract 30 / 47] (score: 2) - Title: Active galactic nucleus activity in brightest cluster galaxies at intermediate redshifts in Sunyaev-Zel'dovich--selected clustersAuthors: N. Hatamkhani, R. E. Skelton, J. Delhaize, M. Hilton, S. I. Loubser, N. Gupta, K. M. Mogotsi,Comments: Accepted for publication in A&A. 19 pages, 17 figures (including appendices)Subjects: astro-ph.GACreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Context. Brightest cluster galaxies (BCGs) host powerful ACTIVE GALACTIC NUCLEi (AGNs) and help regulate the heating--cooling balance of the intracluster medium. While radio-mode feedback is well established locally, its prevalence at intermediate redshifts remains poorly constrained. Aims. We investigate the incidence, accretion state, and host-galaxy properties of AGNs in BCGs in Sunyaev--Zel'dovich (SZ)-selected clusters at $0.3 < z < 0.8$, testing dependences on cosmic epoch, cluster mass, and dynamical state. Methods. We analyse 171 BCGs from the Atacama Cosmology Telescope SZ catalogue, combining Southern African Large Telescope spectroscopy, WISE mid-infrared photometry, and Rapid ASKAP Continuum Survey radio data with X-CIGALE modelling to derive stellar masses, STAR FORMATION rates, and Eddington-scaled accretion rates. Results. Thirty-eight BCGs (22%) host radio-loud AGNs. Only two ($\sim$5%) are high-excitation RADIO GALAXies; the remainder are low-excitation systems. Most AGNs have low Eddington ratios ($-3 \lesssim \log_{10}λ_{\mathrm{Edd}} \lesssim -1$), consistent with radiatively inefficient accretion. Accretion efficiency increases with redshift, while correlations with cluster mass and dynamical state are weak. Radio luminosity is independent of cluster mass. Compared to field radio AGNs, BCG radio-loud AGNs have similar radio powers but are hosted by galaxies $\sim0.8$ dex more massive. Conclusions. BCG radio-loud AGNs at $0.3 < z < 0.8$ are predominantly low-excitation, radiatively inefficient systems, indicating that maintenance-mode accretion was widespread in massive clusters ($M_{500c} \simeq 3.2 \times 10^{14},M_\odot$) by $z \sim 1$. Accretion appears regulated primarily by fuel availability and cosmic evolution rather than global cluster properties, while the cluster environment mainly sets the host-galaxy mass scale.
[abstract 31 / 47] (score: 2) - Title: Shape effects and Shafranov shift reversal in analytical Grad--Shafranov equilibria with non-convex boundariesAuthors: D. Abate,Comments: 19 pages, 7 figures, to be submitted to Physics of PlasmasSubjects: physics.plasm-phCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Analytical Solov'ev equilibria with freely prescribed plasma boundaries can be constructed by enforcing the boundary condition in a least-squares sense on a polynomial basis of homogeneous solutions. Within this approach, a systematic scan of boundary shape is carried out well beyond the convex regime: non-convex star polygons of arbitrary symmetry order and concavity are examined alongside conventional convex tokamak cross-sections, using a quantitative boundary-fidelity criterion to delimit the range of shapes the polynomial basis can represent. For standard convex shapes, poloidal beta is insensitive to shaping due to the Solov'ev current profile, while polygon boundaries raise it monotonically with the number of sides, driven by the flat sides compressing flux surfaces toward the axis. For the Shafranov shift, odd-fold boundaries admit a critical concavity below which the geometric centre of the boundary overtakes the MAGNETic axis, reversing the sign of $Δ/a$; no such reversal occurs for even-fold boundaries, and the effect has no analogue among convex shapes.
[abstract 32 / 47] (score: 2) - Title: CMB-HD Foregrounds: Simulations, Source Detection, and Foreground RemovalAuthors: Amanda MacInnis, Joshua Ange, Neelima Sehgal, Joshua A. Kable, Isabelle Blackstad,Comments: 35 pages, 19 figures, 8 tables. The simulations are available at https://lambda.gsfc.nasa.gov/simulation/ultrahigh_resolution_sims.html , the simulation code is available at https://github.com/CMB-HD/hdsims , and the foreground cleaning code is available at https://github.com/CMB-HD/hdfgcleanSubjects: astro-ph.CO hep-phCreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
We present simulations of the microwave sky at 2.5 arcsecond resolution over 100 square degrees, generated from existing full-sky, lower-resolution simulations, and use them to demonstrate extragalactic foreground removal for a CMB-HD survey. Our cleaning method detects and removes the cosmic infrared background and RADIO GALAXies, yielding source catalogs that are 95% complete down to flux limits of 0.008 and 0.04 mJy at 90 and 148 GHz, respectively. It also identifies and removes galaxy clusters via the thermal Sunyaev-Zel'dovich effect, producing a cluster sample that is nearly complete above $M_{500c} = 5 \times 10^{13} M_\odot$. After cleaning, the residual foreground-plus-noise power spectrum of the coadded 90 and 148 GHz temperature map is 50% higher than previous idealized estimates, increasing cosmological parameter uncertainties for an 11-parameter $Λ$CDM + $N_\mathrm{eff}$ + $\sum m_ν$ + $T_\mathrm{AGN}$ + $A_\mathrm{kSZ}$ + $n_\mathrm{kSZ}$ model by less than 7%. The small impact on cosmological parameters reflects the strong constraining power of CMB POLARIZATION, the temperature-POLARIZATION cross spectra, and CMB lensing spectra reconstructed from POLARIZATION-only estimators, all of which are minimally affected by extragalactic foregrounds. In particular, the survey remains a sensitive probe of light thermal relic particles, achieving $σ(N_\mathrm{eff}) = 0.0154$, which can exclude any new species ($ΔN_\mathrm{eff} \ge 0.027$) with at least 90% confidence. Our simulation and foreground-removal codes are publicly available and should aid the development of analysis pipelines for ultradeep, ultrahigh-resolution microwave surveys.
[abstract 33 / 47] (score: 2) - Title: A pair of unequal JETs imparted the kick velocity to the neutron star of Cassiopeia AAuthors: Dmitry Shishkin, Muhammad Akashi, Noam Soker,Comments: Will be submitted in two days to allow for commentsSubjects: astro-ph.HECreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
We analyze observations of the Cassiopeia A core-collapse SUPERNOVA remnant (CCSNR) and identify a pair of opposite rings, attributing their formation to unequal-energy explosion JETs that also imparted the neutron star (NS) its kick velocity via the kick-BEAP (kick by early asymmetrical pair of JETs) mechanism. We replicate the formation of these ring structures, which we identify as circum-JET rings, with three-dimensional hydrodynamical simulations of two opposite explosion JETs in which the northern JET is much more powerful, forming the larger northern ring known as the Crown. The line connecting the centers of the two opposite rings passes through the previously-established point-symmetric center of Cassiopeia A. The momentum difference between the two JETs also explains the observed southwards NS kick velocity of ~400 km/s. The kick-BEAP and point-symmetric morphology suggest powering and shaping by several pairs of JETs during the explosion process, strengthening the jittering JETs explosion mechanism for the Cassiopeia A CCSNR and core-collapse SUPERNOVAe in general.
[abstract 34 / 47] (score: 2) - Title: The Missing Black Hole in the Large Magellanic Cloud: A Dynamical Prediction for Its Present-Day LocationAuthors: Robin Chisholm, Elena D'Onghia, Niv Drory, Andrew Fox, Noam Libeskind,Comments: 10 pages, 2 figures, submitted to ApJSubjects: astro-ph.GACreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
There are indications that the Large Magellanic Cloud (LMC) hosts a central supermassive BLACK HOLE (SMBH), yet no direct detection exists: one reason is that its present-day location need not necessarily coincide with the photometric or kinematic centers. Here we frame a dynamical targeting problem and predict the present-day sky location of the LMC SMBH. We model the recent LMC-Small Magellanic Cloud (SMC) interaction, which induces a bar-disk offset, and integrate SMBH orbits within a realistic, time-dependent LMC-SMC-Milky Way (MW) potential. We show that the MW tidal field at present epoch exceeds that of the SMC by at least an order of magnitude, setting a preferred direction for coherent, vertical low-amplitude displacements, while the disk asymmetry drives in-plane offsets. Projecting onto the observed LMC frame, the mean of our predicted SMBH probability distribution is located at $(α,δ)=(80.23^{\circ},-69.55^{\circ})$, with a $1σ$ confidence ellipse having semi-major and semi-minor axes of $(a,b)=(1.34^{\circ},0.56^{\circ})$, respectively. This mean is $\sim6$ arcminutes north of the adopted dynamical center, while the mode coincides with the dynamical center and lies well within the $1σ$ confidence region. Furthermore, all literature estimates of the LMC center considered here fall within the $2σ$ confidence region. This provides a concrete, testable target for ongoing and upcoming spectroscopic surveys, transforming the search for the LMC SMBH from an unconstrained problem into a focused observational strategy.
[abstract 35 / 47] (score: 2) - Title: Forged in Quenching: Morphological Transformation across Star-forming and Quiescent Galaxies in EAGLEAuthors: Kai Wang, Carlton Baugh, Sownak Bose, Shaun Cole, Carlos S. Frenk, Hao Fu, Cedric Lacey, Shengdong Lu, Aaron Ludlow, Peder Norberg, Yingjie Peng, Katy L. Proctor, Isabel Santos-Santos, Francesco Shankar, Tom Theuns, Enci Wang, Tao Wang, Vivienne Wild,Comments: 20 pages, 17 + 1 figures, MNRAS in reviewSubjects: astro-ph.GACreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
The connection between morphology and quenching in central galaxies is well established, but its physical origin remains widely debated. We address this by tracing the main progenitor branches of $z=0$ star-forming and quiescent central galaxies in the EAGLE cosmological simulation from $z\gtrsim4$. Their disc-to-total ratio and triaxiality tracks are indistinguishable until $z\approx 1$-$2$, when both diverge concurrently with the onset of quenching, whereas the size and supermassive BLACK HOLE (SMBH) mass differences are established earlier. We identify four physically distinct channels linking galaxy morphology and quenching. First, mergers cause size growth, rotation suppression, triaxiality increase, and SMBH growth, with the accumulated SMBH mass subsequently causes the quenching of galaxies. Second, with merger history controlled, galaxy morphology modulates SMBH growth throughout the star-forming phase: compact, dispersion-dominated galaxies grow their SMBHs faster and are preferentially quenched, producing the size and morphology differences between star-forming and quiescent galaxies. Third, at fixed stellar mass and SMBH mass, compactness further facilitates the quenching of galaxies. Fourth, disc instability transforms compact oblate discs into prolate systems, with substantial size growth and suppressed rotation but negligible stellar mass growth. This secular channel contributes about half of the prolate galaxy population around $M_{\rm star}\approx 10^{10.6}\,\rm M_\odot$. Prior to quenching, the progenitors of quiescent galaxies already have smaller sizes, lower disc-to-total ratios, and more massive SMBHs than star-forming galaxies at the same epoch, by amounts comparable to their differences at $z=0$. Morphology therefore plays an active role in growing the SMBH and quenching the galaxy, rather than being passively inherited through progenitor bias.
[abstract 36 / 47] (score: 2) - Title: Filament Formation via Collision-induced Magnetic Reconnection -- Kinematic FeaturesAuthors: Shuo Kong, Griselda Arroyo-Chávez, Volker Ossenkopf-Okada, Héctor G. Arce, Ralf S. Klessen, Duo Xu, Szu-Ting Chen,Comments: 18 pages, 8 figures, submitted, comments welcomeSubjects: astro-ph.GA physics.plasm-phCreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
The Collision-induced Magnetic Reconnection (CMR) mechanism has recently been proposed as a filament formation model that emphasizes the active role of MAGNETic fields. To enable better observational tests with data from modern telescopes, we provide more specific observable predictions for filaments formed via CMR. Two types of CMR kinematics are revealed in position-velocity (PV) diagrams. First, due to the nature of CMR, the midplane contains a {\it converging motion} close to the filament and two {\it diverging motions} farther from the filament. They exhibit a blueshift, redshift, blueshift, redshift (BRBR) velocity pattern along the line-of-sight when the collision midplane is inclined, giving rise to a special pattern in the PV-diagram. Second, the longitudinal PV-diagram along the filament spine exhibits a velocity oscillating pattern, which is currently attributed to the MAGNETic transport of gas clumps in the {\it converging motion}. The first type of pattern involves emission primarily outside the filament, which can be confused with the environment. The second type, however, mainly emerges from gas inside the filament, thus more robust for observational tests. Both the integral-shaped filament and the Stick filament in the Orion A cloud show the velocity oscillation in PV-diagrams, although the spatial oscillation frequency and their velocity spread differ.
[abstract 37 / 47] (score: 2) - Title: General first-order constitutive equations for a RELATIVISTIC dissipative multi-component fluid in the presence of a weak background electroMAGNETic fieldAuthors: J. Félix Salazar, Ana Laura García-Perciante, Olivier Sarbach,Comments: 18 pages, no figuresSubjects: gr-qcCreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
In this work we establish general constitutive equations for a RELATIVISTIC plasma composed of an arbitrary number of classical, charged, and chemically non-reacting species in the presence of a background electroMAGNETic field. The intensity of the electroMAGNETic force acting on either species is assumed to be comparable with the gradients of the state variables and is thus considered as a first-order driving force for dissipation within the gradient expansion. Assuming that the species share the same temperature and velocity flow when in equilibrium, we determine the entropy production and establish constitutive equations in terms of first-order frame invariant quantities. Conditions on the corresponding transport coefficients are given in order to comply with Onsager's reciprocal relations and the second law of thermodynamics. In particular, we discuss cross effects for the binary mixture which may be relevant for astrophysical and cosmological applications. Finally, we derive a complete set of evolution equations governing the dynamics of a binary mixture propagating on an arbitrary spacetime background.
[abstract 38 / 47] (score: 2) - Title: Right Energy, Wrong Profile: Why the 43 GeV Cluster Line Is Unlikely to Be Dark MatterAuthors: Stefano Profumo,Comments: 34 pages, 20 figuresSubjects: astro-ph.HE astro-ph.CO hep-phCreated: 2026-09-14; Updated: 2026-09-16; Datestamp: 2026-09-16
A narrow gamma-ray line would be a distinctive signature of DARK MATTER, but its interpretation depends as much on its spatial distribution as on its energy. We reanalyze the reported 43 GeV feature in FERMI-LAT observations of Virgo, Fornax, and Ophiuchus. The excess is reproduced in the same public data and survives event-type partitions, a test using data withheld from the original selection, and detector-coordinate permutation tests. Realistic hadronic and inverse-Compton emission is too broad to explain it. A spatial--spectral likelihood analysis restricted to Good Time Intervals and including diffuse backgrounds and catalogued sources finds a broad line-like component. Uniform surface brightness and substructure-enhanced annihilation are preferred, whereas smooth NFW annihilation and a central point source are unlikely explanations. An independent annular analysis agrees: the events associated with the excess extend through much of the virial region. Calibration over 20--70 GeV and five morphologies gives a conditional global significance of approximately $2.7σ$, peaking at 44.5 GeV for uniform brightness. This result is conditional on the preselected three-cluster sample. The broad morphology is the main obstacle to a dark-matter interpretation. Such an interpretation would require photons to be a leading annihilation channel, annihilation to remain efficient in cold subhalos, and subhalos to supply nearly all the cluster luminosity. Yet a boost consistent with $Λ$CDM drives the required two-photon cross section into the range most tightly constrained by Galactic-halo line limits. The most likely explanation is a chance fluctuation amplified by analysis and target-selection effects, possibly compounded by residual Galactic diffuse or unresolved-source mismodeling; if celestial, its morphology makes a simple dark-matter interpretation unlikely.
[abstract 39 / 47] (score: 2) - Title: KEMPIC-3D: A transparent and extensible electroMAGNETic Particle-in-Cell framework for kinetic plasma simulationsAuthors: Jesús E. López, Keren C. Vanegas, Eduardo A. Orozco-Ospino,Comments:Subjects: physics.plasm-phCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
KEMPIC-3D, a fully electroMAGNETic three-dimensional particle-in-cell (PIC) code, has been developed in C/C++ and systematically verified for the self-consistent simulation of kinetic plasma phenomena. The numerical framework combines a staggered Yee finite-difference time-domain solver for Maxwell's equations with a RELATIVISTIC Boris particle pusher, trilinear field interpolation, and charge-conserving current deposition. Its modular architecture emphasizes algorithmic transparency and extensibility, allowing the principal numerical routines to be directly inspected and modified to incorporate additional physical models and computational capabilities. The implementation is assessed through a hierarchy of benchmark problems addressing both the individual numerical components and the self-consistent particle--field coupling. The particle pusher is verified against analytical solutions for RELATIVISTIC charged-particle motion, while the electroMAGNETic field solver is evaluated through guided-wave propagation and grid-convergence analysis. The complete PIC algorithm is subsequently verified through plasma oscillations, global energy conservation, and discrete charge continuity, demonstrating the numerical accuracy, conservation properties, and self-consistency of the coupled formulation. The capabilities of KEMPIC-3D are further demonstrated through a representative simulation of LASER-driven plasma wakefield generation in an underdense plasma. The simulations reproduce the characteristic nonlinear wakefield structure and exhibit stable numerical behavior across different particle discretizations without additional spatial filtering. Together, these results establish KEMPIC-3D as a reliable, transparent, and extensible computational framework for multidimensional kinetic plasma simulations.
[abstract 40 / 47] (score: 2) - Title: Probing Local Charm Hadronization Dynamics with Hadron-Anchored Energy CorrelatorsAuthors: Robert Vertesi,Comments: Submission to SciPostSubjects: hep-phCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
We introduce the hadron-anchored energy correlator (HAEC), a JET-restricted realization of the fragmentation energy correlator and the semi-inclusive energy correlator frameworks, and apply it to heavy-flavor-tagged JETs in hadron collisions. Using \textsc{Pythia}~8 simulations of ${\rm D}^0$- and $Λ_c^+$-tagged JETs, we find a pronounced, localized suppression of energy flow around the $Λ_c^+$ relative to the ${\rm D}^0$, followed by a sharp transition scaling as $θ_0\propto1/p_{\rm T}^{\rm JET}$ with little tune dependence. The conventional JET-axis radial profile shows qualitatively different color-RECONNECTion dependence, suggesting reduced sensitivity of HAEC to JET-axis effects. A beauty-sector study can distinguish a heavy-QUARK-mass origin from a local fragmentation-vertex origin.
[abstract 41 / 47] (score: 2) - Title: Testing a Pre-Supernova Contribution to $^{44}$Ti in Cassiopeia AAuthors: Toshiki Sato, Joshua Issa, Falk Herwig, Yui Kuboike, J. Martin Laming, Kai Matsunaga, Ryo Sawada,Comments: 13 pages, 8 figures. Submitted to ApJSubjects: astro-ph.HE astro-ph.SRCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
The radioactive isotope $^{44}$Ti in Cassiopeia A has been used as a tracer of the innermost ejecta and explosion asymmetries in core-collapse SUPERNOVA explosions. However, recent stellar-evolution models suggest substantial $^{44}$Ti may also be synthesized prior to explosion during oxygen-carbon (O-C) shell mergers, a process proposed for the Cas A progenitor. We investigate this pre-SUPERNOVA contribution by combining NUSTAR measurements of the spatial and kinematic distribution of $^{44}$Ti with X-ray and infrared ejecta diagnostics. The low- and intermediate-velocity $^{44}$Ti components are more closely associated with O-layer tracers than with shocked Fe-rich material. If the $^{44}$Ti associated with the O-layer tracers was synthesized prior to core collapse, it could contribute up to $\sim7\times10^{-5}~M_\odot$, about half of the total. We find that this amount of $^{44}$Ti can be produced in O-C shell-merger models with ingestion rates and convective velocities higher than those in standard one-dimensional stellar-evolution calculations. Stable Fe-group abundance ratios measured with XRISM provide an additional constraint on the explosive contribution, as three-dimensional models with larger $^{44}$Ti yields tend to predict Ti/Fe and Mn/Cr ratios above the observed values. These results suggest that both pre-SUPERNOVA shell-merger nucleosynthesis and explosive burning contribute to the observed $^{44}$Ti.
[abstract 42 / 47] (score: 2) - Title: A 20kA $\pm$0.12% Pulsed Power Supply for the PIP-II ORBUMP Injection Dipole MagnetsAuthors: H. Pfeffer, M. Davidson, D. West, S. Garcia-Schiefelbein, G. Lolov, R. Rivera-Colon,Comments: 2026 IEEE International Power Modulator and High Voltage Conference (IPMHVC)Subjects: physics.acc-phCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
FERMIlab has embarked on its next evolution for future neutrino experiments through the Proton Improvement Plan II (PIP-II). The injection system now requires an increase from a 15 Hz to a 20 Hz injection rate with approximately a 30% increase in the field strength from the original Orbital Bump (ORBUMP) dipole MAGNETs in the Booster ring [1]. The four series connected dipoles will require 3 kV, 20 kA, 660 $μ$s pulses at the aforementioned injection rate with a flatness of $\pm$0.12%. This is achieved through a dual-capacitor pulsed power supply (PPS) comprised of ten parallel cells and must last for 25 years. The supply utilizes high-voltage film caps for the rise and fall portion of the waveform; however, it switches over to a 6 F electrolytic capacitor bank for the flattop portion to meet flatness. The supply utilizes energy recovery to reduce high voltage charging supplies and required power to operate.
[abstract 43 / 47] (score: 2) - Title: JC-PIC: kinetic (PIC-MCC) simulation of lowtemperature plasmas with a documented library of one hundred test casesAuthors: Jean-Pierre Boeuf,Comments: 10 pages, 11 figures. Companion book: doi:10.5281/zenodo.22258142. Software: doi:10.5281/zenodo.22284514. https://jc-pic.orgSubjects: physics.plasm-phCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Over the last twenty years, particle-in-cell simulations with Monte Carlo collisions (PIC-MCC) have given the low-temperature plasma community much of what it knows about electron heating in RF discharges, sheaths and secondary emission, striations, and the instabilities of MAGNETised plasmas. But these results remain in papers, and in codes that only their authors can run. JC-PIC is a free Windows program: a one-dimensional, three-velocity (1D3V) electrostatic PIC-MCC code with a parallel Fortran engine (OpenMP) and a complete graphical interface. It is built around a library of about one hundred ready-to-run cases, each documented, referenced and explained. About half of them reproduce a published result under the original conditions; the others compare the code with a classical analytical result. This overview presents the program, its companion book, and six of the cases from the physics point of view: Langmuir waves from Landau damping to electron trapping, the heating-mode transition in argon RF discharges, the electrical asymmetry effect, the Franck-Hertz experiment treated as a swarm, the striations of a positive column, and the ExB drift instability of Hall thrusters.
[abstract 44 / 47] (score: 2) - Title: Strong Nonlinear Alfvén Wave Interactions in a Laboratory PlasmaAuthors: C. H. K. Chen, S. Dorfman, S. Boldyrev, L. Franci, A. Mallet, M. Abler, S. Vincena, S. Greess, T. A. Carter,Comments:Subjects: physics.plasm-ph physics.space-phCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Alfvén waves and their nonlinear interactions are ubiquitous in space and astrophysical plasmas, and are thought to play important roles in the dynamics of these systems, yet their nature remains to be fully understood. We describe experiments performed on the Large Plasma Device to study the nature of counter- and co-propagating wave interactions relevant to strong Alfvénic turbulence. Both interactions were found to produce a broad spectrum of nonlinear modes as a result of a dominant quadratic nonlinearity. The counter-propagating interaction can be explained through the standard reduced MHD nonlinearity, and the co-propagating interaction can be explained through a recently-proposed model that includes second-order nonlinear terms from Hall MHD that dominate at large imbalance and scale with the ion inertial length. The predictions of the latter model were tested in both the experiment and in 3D hybrid simulations, where the nonlinear mode growth rate and ion inertial scale dependence were found to be consistent. Finally, at the obtained interaction strengths, energy was seen to be transferred to progressively smaller perpendicular scales, consistent with a local cascade, although not a state of fully-developed turbulence. These results reveal and verify the mechanisms occurring in balanced and imbalanced turbulence (as well as other Alfvénic nonlinear processes), and represent an important step towards the generation of controlled Alfvénic turbulence in the laboratory.
[abstract 45 / 47] (score: 2) - Title: Large ${\rm Pm}$ small-scale kinematic dynamo in protoneutron starsAuthors: Shipra Verma, Kannabiran Seshasayanan, Raphaël Raynaud, Jérôme Guilet,Comments: 14 pages, 11 figures, 1 table. Published in Phys. Rev. ESubjects: astro-ph.HE astro-ph.SR physics.flu-dynCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Magnetars are young, isolated neutron stars that possess an exceptionally strong MAGNETic field, with surface dipolar strengths on the order of $10^{15}$ G. One of the plausible scenarios for generating such a strong field is an exponential amplification by a turbulent convective dynamo during the protoneutron star phase. However, the short expected duration of the convection ($\sim 10$ s) imposes a stringent constraint on the dynamo growth rate. We perform an extensive set of 82 three-dimensional convective dynamo simulations in the anelastic approximation and investigate the kinematic phase to quantify the dynamo growth rate $γ$. We find that $γ$ increases with both the MAGNETic Prandtl number ${\rm Pm}$ and the Rayleigh number ${\rm Ra}$, with the most unstable mode becoming highly non-axisymmetric and multipolar. We further observe a gradual transition from large-scale to small-scale dynamo as the MAGNETic Reynolds number ${\rm Rm}$ increases, resulting in a MAGNETic field that is predominantly concentrated at small scales. The trend remains unchanged when the outer MAGNETic boundary condition is varied. Since resolving the increasingly small scales becomes numerically impractical, we employ the theoretical small-scale Kazantsev dynamo model to explore the large ${\rm Pm}$ regime characteristic of protoneutron stars. The model qualitatively captures the growth rate behaviour observed in simulations and, upon extrapolation to the large ${\rm Pm}$ limit, indicates that $γ$ is only weakly dependent on the resistivity in a PNS. Under conditions relevant to the PNS, this model predicts a MAGNETic energy growth rate of the order of $\sim 1$ ms$^{-1}$.
[abstract 46 / 47] (score: 2) - Title: Spontaneous wandering of the MAGNETic axis in pulsars: 3D MAGNETo-thermal simulations and the imprint on braking indicesAuthors: Clara Dehman, Daniele Viganò,Comments: 21 pages, 12 figures. Submitted for publicationSubjects: astro-ph.HECreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
Braking index measurements of hundreds of pulsars, despite observational caveats, show a clear trend: $n<3$ at early ages, $n>3$ at middle ages, and increasingly large, fluctuating values at larger characteristic ages. Crustal MAGNETic fields in isolated neutron stars evolve through Ohmic dissipation and non-linear Hall redistribution across scales, with additional early-time contributions from the chiral MAGNETic effect and post-burial re-emergence. Initial conditions are usually assumed dipole-dominated, whereas more complex and realistic fields, with energy spread more evenly over a broad range of scales, have not been explored in this context. We assess how the internal dynamics of initially non-trivial fields change the dipolar field strength and obliquity, and how their combined contribution to the braking index $n$, together with that of the alignment, compares with the observed values. To this end we perform long-term 3D MAGNETo-thermal simulations, for configurations ranging from the dipole-dominated case to tangled, small-scale-dominated fields. Small-scale dominated configurations with weak dipolar components show rich dynamics: the dipolar mode is continuously fed by the small scales and may grow or decay depending on the initial spectrum, driving $n<3$ or $n>3$, while the obliquity varies on timescales as short as ${\cal O}$(kyr). These spontaneous changes often dominate the alignment torque and can account for the large values of $n-3$ of either sign observed at characteristic ages $τ_c\gtrsim10^5$ yr, unlike the dipole-dominated models. However, short-term MAGNETospheric fluctuations or superfluid-driven variations of the torque may still be needed to explain the measurements and the structured timing residuals quantitatively. Future work comparing these models with the observed timing properties could fine-tune the most promising initial configurations.
[abstract 47 / 47] (score: 2) - Title: Chern bounds and tangent geometry of polarized Calabi-Yau threefoldsAuthors: Atsushi Kanazawa,Comments:Subjects: math.AG hep-th math.CVCreated: 2026-09-15; Updated: 2026-09-16; Datestamp: 2026-09-16
We bring new insights into the numerical geography of polarized Calabi-Yau threefolds through the first JET bundle, tangent geometry and projective duality. Let $X$ be a Calabi-Yau threefold with a very ample POLARIZATION $H$. We use mixed intersections on the projectivized dual of the first JET bundle to prove a quadratic inequality relating the degree $d=H^3$ and Chern numbers. Combining this inequality with hyperplane-section and tangent-variety estimates yields improved uniform bounds $-4d-80\le h^{1,1}(X)-h^{2,1}(X)\le\frac{173}{66}d$. For nondegenerate embeddings in $\mathbb{P}^6$, we improve the upper bound on the degree from $41$ to $39$ and express the tangent degree as a quadratic polynomial in $d$. We also prove that, for every $m\ge2$, the tangent-incidence morphism associated with $|mH|$ is the normalization morphism of the tangent variety. For $m=1$, we conjecture tangent degree $1$ for complete embeddings in $\mathbb{P}^N$ with $N\ge7$ and verify this for several families, including general intersections of four quadrics and general GPK$^3$ threefolds.
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