Current date: 2026-09-03

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Created/updated limit: 2026-08-27 (7 days ago)

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OAI-PMH request: http://export.arxiv.org/oai2?verb=ListRecords&from=2026-09-03&until=2026-09-03&set=physics&metadataPrefix=arXiv

Scoring abstracts

Number of records retrieved: 219

Keyword score statistics

score 7 -- 1 abstracts

score 4 -- 4 abstracts

score 3 -- 1 abstracts

score 2 -- 3 abstracts

in total -- 9 abstracts

Articles that appeared on 2026-09-03

[abstract 1 / 9] Wow! (score: 7)
arXiv:2509.03576 [pdf, ps, other]

Title: How similar are narrow-line Seyfert 1 galaxies and high-z type 1 AGN?

Authors: Marco Berton, Emilia Järvelä, Alessia Tortosa, Chiara Mazzucchelli,

Comments: 18 pages, 8 figures. Published in the Open Journal of Astrophysics

Subjects: astro-ph.GA astro-ph.HE

Created: 2026-09-01; Updated: 2026-09-03; Datestamp: 2026-09-03

The recent observations of highly accreting supermassive BLACK HOLEs (SMBH) at very high redshift ($z>$4) with the James Webb Space Telescope (\textit{JWST}) allowed us to shed light for the very first time on the early evolutionary phases of ACTIVE GALACTIC NUCLEi (AGN). Perhaps unsurprisingly, several of the physical properties observed in these new objects, including those known as little red dots (LRDs), are closely reminiscent of the low-mass and high-Eddington AGN in the local Universe, and in particular of the class of narrow-line Seyfert 1 (NLS1) galaxies. However, some differences also emerged, likely due to the radically different evolutionary path and the environment where LRDs and NLS1s live. In this work, we review the multiwavelength properties of local NLS1s and briefly compare them with type 1 AGN found at high-$z$, showing that despite some differences, the study of NLS1s can be extremely useful to better understand the extreme accretion physics of high-$z$ QUASARs and the early stages of AGN evolution. The goal of this review is to provide the high-z community a handbook to compare their new sources with those already known in the local Universe, and to give the low-z community a starting point to venture in the early phases of AGN evolution.

[abstract 2 / 9] Yes (score: 4)
arXiv:2605.13011 [pdf, ps, other]

Title: No Measurable Changes in Radio and X-ray Emission Surrounding Glitches in the Young Pulsar PSR J2229+6114

Authors: Wenke Xia, Robert A. Main, Mason Ng, Victoria M. Kaspi, Jason W. Hessels, Alyssa Cassity, Abigail K. Denney, Emmanuel Fonseca, Deborah C. Good, Ajay Kumar, Lars Kunkel, Bradley W. Meyers, Aaron B. Pearlman, Ingrid Stairs,

Comments: 14 pages, 8 figures. Accepted for publication in ApJ

Subjects: astro-ph.HE

Created: 2026-09-01; Updated: 2026-09-03; Datestamp: 2026-09-03

We present our first result from an ongoing pulsar glitch monitoring campaign at the Canadian Hydrogen Intensity Mapping Experiment (CHIME), in which we analyzed the radio and X-ray emission surrounding four glitches in PSR~J2229+6114. Using daily CHIME observations, we detected a glitch in PSR~J2229+6114 in near-real time and triggered an X-ray follow-up with the Nuclear Spectroscopic Telescope Array (NUSTAR) two days after the glitch. We identified three additional glitch events in archival CHIME/Pulsar observations that coincided with an independent X-ray observing campaign with the Neutron star Interior Composition Explorer (NICER).. Our data show there is no measurable change in the source's X-ray and radio emission during the four glitch events, in stark contrast to the post-glitch activity in high-MAGNETic-field, rotation-powered pulsars (RPPs), which have been observed to exhibit MAGNETar-like X-ray outbursts immediately after large glitches. Those high-MAGNETic-field (high-$B$) RPPs are considered transitional objects between ordinary RPPs and MAGNETars, thereby leading to a unifying neutron star model in which the inferred dipolar surface MAGNETic field strength serves as a unifying parameter. However, such a model remains challenged, in part, by the lack of constraints near the low-$B$ end of the high-$B$ regime, and our result provides additional evidence that MAGNETar-like post-glitch activity is likely more common among high-$B$ RPPs.

[abstract 3 / 9] Yes (score: 4)
arXiv:2606.02748 [pdf, ps, other]

Title: Elemental COSMIC RAY spectra reveal two populations of Galactic sources and an immediate transition to an extragalactic component after the knee

Authors: Timur A. Dzhatdoev, Anatoly A. Semenov,

Comments: 13 pages, 11 figures, 3 tables. Joint fit added (Sect. 5); some mistakes corrected in Discussion/Conclusions

Subjects: astro-ph.HE

Created: 2026-09-01; Updated: 2026-09-03; Datestamp: 2026-09-03

The energy spectra for individual elements and/or for groups of elements in COSMIC RAYs (CR) in the energy range between 100 $\times$ Z GeV and 10$^{3}$ $\times$ Z PeV (where Z is the charge number of the nucleus) have a number of features, including two steepenings ("knees") with the rigidity-dependent energies $E_{k1} \approx$ 15 $\times$ Z TeV and $E_{k2} \approx$ 3 $\times$ Z PeV and three hardenings ("ankles") at $E_{a1} \approx$ 500 $\times$ Z GeV; for protons $E_{a2-p} \approx$ 150 TeV and $E_{ a3-p} \approx$ 50 PeV. While the values of $E_{a1}$ for different nuclei are rigidity-dependent, the values of $E_{a2}$ (and probably of $E_{a3}$) are not: $E_{a2-He} \approx$ 1 PeV for Helium. The recent advances in precision measurements of the elemental CR spectra in the DAMPE and LHAASO experiments, and, to some extent, in IceTop and other experiments, make it possible, for the first time, to clarify the origin of the aforementioned spectral features. We show that the elemental CR spectra are reasonably well described with a sum of three components: 1) a low-energy Galactic component with a convex spectral shape reflecting the accelerated particle spectrum in the source; this component peters out after the TeV knee, 2) a high-energy Galactic component including the PeV knee, and 3) an extragalactic component. There is no need for any third, additional component of Galactic COSMIC RAYs in the energy range between 10 PeV and 1 EeV.

[abstract 4 / 9] Yes (score: 4)
arXiv:2609.01711 [pdf, ps, other]

Title: JWST Reveals a Candidate Supermassive Black Hole Binary at z=4.3 in the Brightest Sub-millimeter Galaxy in COSMOS-Web

Authors: Jed McKinney, Ansh Gupta, Julian B. Munoz, John Chisholm, Caitlin M. Casey, Stephanie M. Urbano Stawinski, Olivia Cooper, Erini Lambrides, Hollis Akins, Maximilien Franco, Archana Aravindan, Seiji Fujimoto, Kohei Inayoshi, Andreas L. Faisst, Jeyhan S. Kartaltepe, Michael Boylan-Kolchin,

Comments: 17 pages, 12 figures, accepted to ApJL

Subjects: astro-ph.GA astro-ph.CO

Created: 2026-09-01; Updated: 2026-09-03; Datestamp: 2026-09-03

We present JWST/NIRSpec PRISM and G395M grating spectroscopy for AzTEC-1, a massive sub-mm bright galaxy at $z=4.34$ in the COSMOS extragalactic field. The PRISM spectrum reveals strong H$α$, a significant Balmer break, and no H$β$ detection, indicating a $100-400$ Myr-old stellar population and high dust attenuation. BPT line ratios indicate the presence of an Active Galactic Nucleus (AGN). Decomposing narrow and broad line components, we recover broad, blueshifted H$α$ with a velocity offset of $1245{\,\rm km\,s^{-1}}$ from the systemic narrow line velocity and with FWHM$\,\sim2500\,{\rm km\,s^{-1}}$. AzTEC-1's smooth morphology and stellar age is suggestive of a past merger-induced starburst period that would have brought in a second supermassive BLACK HOLE, raising the possibility for a binary supermassive BLACK HOLE system. In this scenario, we assume that the lower mass BLACK HOLE hosts a broad line region orbiting a quiescent primary. Evidence for an extended outflow is not found in the 2D spectrum, NIRCam imaging, resolved ALMA observations of dust continuum, or CO, [C II]$_{157\,μ\rm m}$ and [N II]$_{\rm 205\,μm}$ kinematics. AzTEC-1's high central gas mass surface density and dynamically unstable gas disk indicates that massive gas clouds external to the candidate binary SMBH's orbit might have played a role in stalling infall from $\sim10$ Myr to $\sim100$ Myr through dynamical torques, which has been theorized to occur in the nuclei of massive galaxies like AzTEC-1. If the supermassive BLACK HOLE binary is confirmed, AzTEC-1 would be an excellent laboratory into the astrophysics driving low-frequency gravitational wave detections.

[abstract 5 / 9] Yes (score: 4)
arXiv:2609.01977 [pdf, ps, other]

Title: Inflationary Magnetogenesis with f(R) Gravity: Dynamics, Constraints, and Observational Signatures during Reheating

Authors: Shuang Liu, Bo-yu Zhao, Yu Li, Yao-chuan Wang,

Comments: 13 pages, 8 figures

Subjects: astro-ph.CO gr-qc

Created: 2026-09-02; Updated: 2026-09-03; Datestamp: 2026-09-03

Inflationary MAGNETogenesis provides a promising mechanism for generating primordial large-scale MAGNETic fields, but faces challenges. In this paper, we extend the Ratra model to a non-minimal $f(R)$ gravity framework, appearing in the Lagrangian in the form $f^2(η) F_{μν}F^{μν}$, to break the conformal invariance of the standard electroMAGNETic action. Focusing on the post-inflationary reheating epoch, we derive analytic expressions for the MAGNETic and electric energy density spectra by constructing a broken-power-law evolution for the scale factor and the coupling function across the inflation-to-reheating transition. Three key theoretical constraints are imposed on the model parameter space: the strong coupling condition, the backreaction constraint, and the CMB isotropy requirement. Through numerical calculations, we obtain predictions for the present-day MAGNETic field strength $B_0$ and coherence length $L_{c0}$ for various combinations of the inflationary energy scale $H_f$ and the reheating temperature $T_r$. We further incorporate the nonlinear effects of MAGNETohydrodynamic (MHD) turbulence after reheating, including the inverse transfer process, which significantly enhances the coherence length (up to $0.1$ Mpc) while reducing the field strength by several orders of magnitude. By comparing with observational constraints from radio observations and FERMI-LAT gamma-ray data, we demonstrate that the inflationary energy scale $H_f$, the reheating temperature $T_r$, the parameter $β$, and the e-folds numbers $N_f$, $N_r$ must satisfy stringent joint constraints. This work provides a viable theoretical framework for inflationary MAGNETogenesis that simultaneously satisfies theoretical consistency conditions and current observational bounds.

[abstract 6 / 9] (score: 3)
arXiv:2606.10283 [pdf, ps, other]

Title: First Principles Magnetohydrodynamical Theory for the Expanding Box Model: Effects on Expansion-Induced Alfvén Wave Reflection

Authors: Sebastián Saldivia, Nicolás Villarroel-Sepúlveda, Sebastián Echeverría-Veas, Felipe A. Asenjo, Pablo S. Moya,

Comments: 21 pages, 5 figures

Subjects: physics.plasm-ph astro-ph.SR

Created: 2026-09-01; Updated: 2026-09-03; Datestamp: 2026-09-03

The Expanding Box Model (EBM) has been widely employed to simulate multiscale plasma phenomena in the expanding solar wind by transforming the MHD equations to a co-moving, non-inertial frame. However, traditional formulations have suffered from historical ambiguity regarding the physical separation between the co-moving and inertial reference frames, primarily arising from a classical approximation of an invariant MAGNETic field between them. To resolve this inconsistency, we reformulate the EBM from first principles using a fully covariant approach. Here, we model the expanding solar wind frame as an anisotropic expanding spacetime metric, allowing us to incorporate radial acceleration profiles and differential transverse expansion, ensuring that all physical fields are correctly transformed by expansion. We demonstrate that asymmetries identified in previous EBM-MHD literature are direct consequences of neglecting the tensorial scaling of the MAGNETic field. Our covariant treatment eliminates these residues, restoring symmetry in the co-moving frame. Projecting our system back into the inertial frame clarifies the distinction between local plasma dynamics and plasma expansion, revealing the anisotropy of the Parker spiral as a geometric projection. Furthermore, linear wave analysis using Elsässer variables reveals that plasma expansion induces a low-frequency cutoff and geometric damping. Numerical integration demonstrates that expansion drives the reflection of Alfvén waves, generating counter-propagating modes primarily at low frequencies relative to the expansion rate, while high frequencies converge to the WKB approximation. This provides a consistent foundation for simulations, establishing that expansion can serve as a source of counter-propagating waves necessary to drive solar wind turbulence at low frequencies.

[abstract 7 / 9] (score: 2)
arXiv:2605.05362 [pdf, ps, other]

Title: Constraining Lorentz symmetry breaking in bumblebee gravity with extreme mass-ratio inspirals

Authors: Sheng Long, Zhong-wu Xia, Huajie Gong, Zhoujian Cao, Qiyuan Pan, Jiliang Jing,

Comments: Accepted for publication in Chinese Physics C

Subjects: gr-qc

Created: 2026-09-01; Updated: 2026-09-03; Datestamp: 2026-09-03

Extreme mass-ratio inspirals (EMRIs), with their long-lived and highly RELATIVISTIC orbital evolution, can probe strong-field spacetime geometry and provide an important means to test general relativity. In this work, we investigate EMRI waveforms in a Schwarzschild-like BLACK HOLE spacetime arising in bumblebee gravity, where Lorentz symmetry breaking (LSB) is characterized by a dimensionless parameter $\ell$. We construct EMRI waveforms within the Augmented Analytic Kludge (AAK) framework using the modified orbital frequencies and fluxes. We find that $\ell$ significantly affects the orbital evolution and thereby modifies the waveform. These modifications grow with increasing $\ell$ and are further enhanced for more eccentric orbits. Furthermore, using Bayesian analysis, we obtain the posterior distributions of EMRI with the parameter $\ell$ included. Our results show that all injected source parameters are recovered within their $1\,σ$ credible intervals. We find that the bumblebee parameter $\ell$ can be constrained with an uncertainty of order $\mathcal{O}(10^{-4})$ by LISA.

[abstract 8 / 9] (score: 2)
arXiv:2609.01750 [pdf, ps, other]

Title: The Fusion Equilibrium Challenge: Inferring Magnetic Geometry Without Magnetic Diagnostics

Authors: Tapan Ganatma Nakkina, Matthew Waller, Craig Michoski, Brian Sammuli, David R. Hatch, William Boyes, Mitchell Clark, Raffi Nazikian, Sterling Smith,

Comments:

Subjects: physics.plasm-ph

Created: 2026-09-01; Updated: 2026-09-03; Datestamp: 2026-09-03

Next-generation fusion reactor devices such as SPARC, ARC, and CFETR will operate in extreme neutron environments that compromise the MAGNETic sensors traditionally used to reconstruct plasma equilibria. However, reliable knowledge of the plasma equilibrium--including MAGNETic flux surfaces, safety factor profiles, and shaping parameters--is indispensable for real-time control, disruption avoidance, and physics interpretation. The Fusion Equilibrium Challenge invites the NeurIPS community to confront a deceptively simple but scientifically rigorous inverse problem: reconstruct the two-dimensional poloidal flux function psi(R,Z) and a suite of scalar equilibrium parameters from non-MAGNETic diagnostics alone, namely external poloidal-field coil currents and Thomson-scattering electron temperature/density profiles. The challenge provides the first open-access, harmonized multi-machine benchmark for fusion, releasing a curated dataset of 9,113 DIII-D shots and 2,416 MAST shots--filtered for Thomson-diagnostic availability, feature completeness, and EFIT-reconstruction quality. Each shot is packaged into a standard Parquet file containing approximately 260 (DIII-D) / approximately 80 (MAST) EFIT flux maps and rich high-rate diagnostics. Two complementary awards reward intra-machine reconstruction fidelity (S_model) on DIII-D and zero-shot cross-machine generalization (G_ratio) to the topologically distinct MAST spherical tokamak. We argue that the challenge functions as a benchmark for reactor-ready equilibrium inference and as a probe of how far machine learning can be pushed toward truly machine-agnostic plasma state estimation.

[abstract 9 / 9] (score: 2)
arXiv:2609.01890 [pdf, ps, other]

Title: A novel objective function minimizes resonant trapped energetic particle losses in stellarators

Authors: John Anthony Labbate, Elizabeth J. Paul, Amelia Chambliss,

Comments:

Subjects: physics.plasm-ph

Created: 2026-09-01; Updated: 2026-09-03; Datestamp: 2026-09-03

Near-omnigenous stellarators are susceptible to energetic particle (EP) losses due to resonances between trapped EPs and non-omnigenous perturbations to the MAGNETic field. Existing bounce-averaged objectives such as $Γ_c$, $Γ_δ$ , and $Γ_α$ target the non-resonant misalignment of drift and flux surfaces, but they do not capture resonant convective or diffusive motion. We develop a discrete map theory for the bounce points of trapped EPs in near-omnigenous fields, in which phase-space islands form due to resonance between the precession and bounce frequencies. We introduce $Δ_{res}$, a differentiable, bounce-averaged objective function that penalizes the widths of these islands, promoting phase-space integrability. Optimizing a quasi-axisymmetric configuration using $Δ_{res}$ combined with a two-term quasi-symmetry objective yields a factor-of-four improvement in EP confinement by displacing low-order resonances and forming EP transport barriers. $Δ_{res}$ is a powerful tool to combat both resonant convective and diffusive losses in power plant-relevant stellarators.