Current date: 2026-01-16
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Number of records retrieved: 675
Keyword score statistics
score 8 -- 1 abstracts
score 7 -- 2 abstracts
score 6 -- 1 abstracts
score 5 -- 2 abstracts
score 4 -- 2 abstracts
score 3 -- 10 abstracts
score 2 -- 15 abstracts
in total -- 33 abstracts
Articles that appeared on 2026-01-16
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[abstract 1 / 33] Wow! (score: 8)
- Title: Neutrino and pair creation in RECONNECTion-powered coronae of accreting BLACK HOLEsAuthors: D. Karavola, M. Petropoulou, D. F. G. Fiorillo, L. Comisso, L. Sironi,Comments: 33 pages, Published on JCAP (JCAP04(2025)075)Subjects: astro-ph.HECreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
A ubiquitous feature of accreting BLACK HOLE systems is their hard X-ray emission which is thought to be produced through Comptonization of soft photons by electrons and positrons in the vicinity of the BLACK HOLE, in a region with optical depth of order unity. The origin and composition of this Comptonizing region, known as the corona, is a matter open for debate. In this paper we investigate the role of RELATIVISTIC protons accelerated in black-hole MAGNETospheric current sheets for the pair enrichment and neutrino emission of AGN coronae. Our model has two free parameters, namely the proton plasma MAGNETization $σ_{\rm p}$, which controls the peak energy of the neutrino spectrum, and the Eddington ratio $λ_{\rm X, Edd}$ (defined as the ratio between X-ray luminosity $L_{\rm X}$ and Eddington luminosity $L_{\rm Edd}$), which controls the amount of energy transferred to secondary particles. For sources with $λ_{\rm X, Edd} \gtrsim λ_{\rm Edd, crit}$ (where $λ_{\rm Edd, crit} \sim 10^{-1}$ for $σ_{\rm p}=10^5$ or $\sim 10^{-2}$ for $σ_{\rm p}=10^7$), proton-photon interactions and $ γγ$ annihilation produce enough secondary pairs to achieve Thomson optical depths $τ_{\rm T} \sim 0.1-10$. In the opposite case of $λ_{\rm X, Edd} \lesssim λ_{\rm Edd, crit}$, the coronal pairs cannot originate only from hadronic interactions. Additionally, we find that the neutrino luminosity scales as $L^2_{\rm X}/L_{\rm Edd}$ for $λ_{\rm X, Edd} \lesssim λ_{\rm Edd, crit}$, while it is proportional to $L_{\rm X}$ for higher $λ_{\rm X, Edd}$ values. We apply our model to four Seyfert galaxies, including NGC 1068, and discuss our results in light of recent IceCube observations.
[abstract 2 / 33] Wow! (score: 7) - Title: Decoding Cygnus X-2: The Critical Role of Reflection in IXPE DataAuthors: Honghui Liu, Jiachen Jiang, Adam Ingram, Cosimo Bambi, Andrew C. Fabian, Ruben Farinelli, Renee Ludlam, Nathalie Degenaar, Jakub Podgorny, Andrea Santangelo, James F. Steiner, Andrew J. Young, Zuobin Zhang,Comments: 18 pages, 9 figures, accepted for publication in JHEApSubjects: astro-ph.HECreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
We present a spectro-polarimetric re-analysis of the first IXPE observation of Cygnus X-2 which we determine to be mainly in the normal branch, from quasi-simultaneous observations with NUSTAR, NICER, and INTEGRAL. We measure the hard X-ray POLARIZATION angle and find it to be consistent with the previously measured position angle of the radio JET. Leveraging NUSTAR's detection of both the RELATIVISTIC Fe K emission line and the Compton hump, we constrain the flux contribution of the reflected emission from the inner accretion disk to be 10% of the total X-ray flux in the IXPE energy band. Unlike previous studies that modeled only the Fe K emission line, we fit the full-band reflection spectrum using a fully RELATIVISTIC disk model. There is strong degeneracy between the Comptonized and reflection components. Given that the Comptonized component is not expected to be highly polarized, a POLARIZATION degree of approximately 20% for the reflection component could explain the X-ray POLARIZATION data from IXPE. We also discuss the disk inclination angle inferred from our spectro-polarimetric modeling, as well as other possible explanations for the data.
[abstract 3 / 33] Wow! (score: 7) - Title: New Hard X-Ray and Multiwavelength Study of the PeVatron Candidate PWN G0.9+0.1 in the Galactic Center RegionAuthors: Giulia Brunelli, Kaya Mori, Jaegeun Park, Jordan Eagle, Moaz Abdelmaguid, Melania Nynka, Hongjun An, Aya Bamba, Joseph D. Gelfand, Gabriele Ponti, Samar Safi-Harb, Vito Sguera, Cristian Vignali, Jooyun Woo, Roberta Zanin,Comments: Accepted for publication in the Astrophysical JournalSubjects: astro-ph.HECreated: 2026-01-14; Updated: 2026-01-16; Datestamp: 2026-01-16
We present a new X-ray study and multiwavelength spectral energy distribution (SED) modeling of the young pulsar wind nebula (PWN) powered by the energetic pulsar PSR J1747-2809, inside the composite SUPERNOVA remnant (SNR) G0.9+0.1, located in the Galactic Center region. The source is detected by NUSTAR up to 30 keV with evidence for the SYNCHROTRON burnoff effect in the changing spatial morphology with increasing energy. The broadband 2-30 keV spectrum of PWN G0.9+0.1 is modeled by a single power law with photon index $Γ=2.11\pm0.07$. We combined the new X-ray data with the multiwavelength observations in radio, GeV, and TeV gamma rays and modeled the SED, applying a one-zone and a multi-zone leptonic model. The comparison of the models is successful, as we obtained physically compatible results in the two cases. Through the one-zone model, we constrain the age of the system to $\sim2.2$ kyr, as well as reproduce the observed PWN and SNR radio sizes. In both the one-zone and multi-zone leptonic models, the electron injection spectrum is well-described by a single power law with spectral index $p \sim 2.6$ and a maximum electron energy of $\sim2$ PeV, suggesting the source could be a leptonic PeVatron candidate. We estimate the average MAGNETic field to be $B_{\rm PWN} \sim 20\ μ$G. We also report the serendipitous NUSTAR detection of renewed X-ray activity from the very faint X-ray transient XMMU J174716.1-281048 and characterize its spectrum.
[abstract 4 / 33] Yes (score: 6) - Title: Multimessenger Prospects for Low-Luminosity Gamma-Ray Bursts: Joint Neutrino and X-Ray ObservationsAuthors: Wenkang Lian, He Gao, Shunke Ai, B. Theodore Zhang,Comments:Subjects: astro-ph.HECreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
Low--luminosity GAMMA-RAY BURSTs (LLGRBs) are promising candidates for high-energy neutrinos, yet no coincident neutrino events have been detected so far. Recent advances in X-ray time-domain astronomy, together with the development of next-generation neutrino telescopes, open new opportunities for joint X-ray and neutrino observations of these transients. We calculate the JET dynamical evolution and the associated neutrino production for both non-MAGNETized and MAGNETized outflows. For individual events, joint X-ray and neutrino detection is generally limited to nearby LLGRBs or sources with high luminosities. Thus, we consider a next-generation neutrino telescope with an effective area enhanced by a factor of $\sim30$ relative to IceCube. In the non-MAGNETized scenario, joint detection of individual events is enabled for sources with typical isotropic luminosities of $L_{\mathrm{iso}}\sim10^{47}\,\mathrm{erg\,s^{-1}}$ out to luminosity distances of $D_L\sim1.6\times10^{2}\,\mathrm{Mpc}$, corresponding to an expected detection rate of order $1$ per year. In contrast, for the MAGNETized scenario at the same luminosity, the accessible distance is significantly reduced, with joint observations confined to sources within $D_L\sim6.5\times10^{1}\,\mathrm{Mpc}$ and an expected detection rate of order $0.5$ per year. For stacked samples of $\sim100$ MAGNETized LLGRBs, stacking substantially enlarges the accessible distance range, enabling joint observations for sources with representative luminosities of $L_{\mathrm{iso}}\sim1\times10^{47}\,\mathrm{erg\,s^{-1}}$ out to $D_L\lesssim7.0\times10^{2}\,\mathrm{Mpc}$ and corresponding to an expected detection rate of order $2$ per year. These results demonstrate that joint X-ray and next-generation neutrino observations enable a practical multimessenger probe of LLGRBs.
[abstract 5 / 33] Yes (score: 5) - Title: Testing the correlation between bending angle and POLARIZATION properties of bent RADIO GALAXiesAuthors: S. Vanderwoude, E. Osinga, B. M. Gaensler, J. L. West, R. J. van Weeren,Comments: 26 pages, 12 figures, 2 tablesSubjects: astro-ph.GACreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
The bending of RADIO GALAXies in galaxy clusters is expected to be caused by interactions with the local environment. The physical processes responsible for JET bending, and their influence on the POLARIZATION properties of RADIO GALAXies, remain poorly understood, leading to the question of whether JET properties in bent RADIO GALAXies differ from those in linear RADIO GALAXies. Using a sample of 24 polarized bent RADIO GALAXies, observed with the Karl G. Jansky Very Large Array at 1--2 GHz, we test for correlation of bending angle with POLARIZATION parameters measuring Faraday rotation, intrinsic fractional POLARIZATION, and Faraday rotation dispersion, used here as a measure of turbulence along the line of sight. We find no statistically significant correlations. At the spatial resolution of our dataset (3--46 kpc, median 18.4 kpc), our results indicate that we are primarily probing larger-scale intracluster medium effects not related to bending angle. The absence of a statistically significant correlation suggests that bent RADIO GALAXies are reliable probes of intracluster MAGNETic fields, because their intrinsic properties do not appear to introduce systematic biases into measured POLARIZATION parameters. We do detect a preference for source MAGNETic field vectors to align with the direction of JET bending. Finally, we estimate that the POSSUM and SKA surveys will contain $\gtrsim$300 and $\gtrsim$1000 polarized RADIO GALAXies, respectively, providing large future samples with a range of bending angles and similar redshift distribution and number of beams per source as in our sample, enabling our results to be tested with greater statistical power.
[abstract 6 / 33] Yes (score: 5) - Title: On the Physical Origins of the Millimeter Fundamental Plane in Active Galactic NucleiAuthors: Kratika Mazde, Angelo Ricarte, George N. Wong,Comments: 13 pages, 5 figures, submitted to ApJ, comments welcomeSubjects: astro-ph.HECreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
Observations of ACTIVE GALACTIC NUCLEi have revealed a correlation between millimeter luminosity, X-ray luminosity, and mass, suggesting the emission in each of these bands is powered by a common source. Starting with a set of five general RELATIVISTIC MAGNETohydrodynamic simulations with dynamically important MAGNETic fields, we perform ray-tracing calculations to produce spectra including SYNCHROTRON emission, bremsstrahlung emission, and Compton scattering. Our models with similar Eddington ratios to the objects for which the relationship was inferred naturally reproduce observations without tuning. Our lower Eddington ratio models depart from this relationship, likely attributable to an observational bias against extremely low accretion rates. We find that inverse Compton scattering dominates the production of X-rays over bremsstrahlung radiation in almost all models, and in all models consistent with the observed correlation. We find only a modest spin dependence in this relationship. This study demonstrates that a compact, hot accretion flow with dynamically important MAGNETic fields can naturally explain observed millimeter and X-ray properties in low-luminosity ACTIVE GALACTIC NUCLEi. Future work should explore the impacts of non-thermal electron populations, weaker MAGNETic fields, and radiative cooling.
[abstract 7 / 33] Yes (score: 4) - Title: Non-Monotonic Enhancement of the Magnetic Penrose Process in Kerr-Bertotti-Robinson Spacetime and its Implication for Electron AccelerationAuthors: Mirjavoxir Mirkhaydarov, Tursunali Xamidov, Pankaj Sheoran, Sanjar Shaymatov, Hemwati Nandan,Comments: 16 pages, 8 captioned figures and 2 tablesSubjects: gr-qcCreated: 2026-01-14; Updated: 2026-01-16; Datestamp: 2026-01-16
We studied the MAGNETic Penrose process (MPP) in the Kerr-Bertotti-Robinson (KBR) spacetime, an exact rotating electrovacuum solution describing a BLACK HOLE (BH) immersed in an intrinsic, uniform electroMAGNETic field. We analyze the behavior of charged particles in this geometry and find that the spacetime structure itself responds non-monotonically to the background MAGNETic field $B$. Specifically, both the event horizon and the static limit surface first expand as $B$ increases, reach a maximum size at an intermediate field strength, and then contract toward the extremal limit. Although the ergoregion itself shrinks monotonically with $B$, this structural feature gives rise to a pronounced non-monotonic dependence of the energy extraction efficiency on the MAGNETic field $B$, i.e., the efficiency initially rises, attains a maximum value, and subsequently falls as the extremal condition is approached. This contrasts sharply with the monotonic trends usually associated with MAGNETic enhancements in the Kerr geometry. We further explore an astrophysical application of the MPP by estimating the maximum energy of electrons escaping from the ergoregion of the KBR BH. Modeling neutron beta decay occurring near the event horizon, we derive an analytical expression for the energy gained by electrons accelerated by the MAGNETic field. Applying our results to the supermassive BH at the Galactic center, $\mathrm{SgrA}^*$, we find that electrons can be accelerated up to energies of $\sim 10^{15}\,\mathrm{eV}$ for realistic values of the spin and MAGNETic field. Although these energies exceed the observed upper range of cosmic-ray electrons, radiative losses such as SYNCHROTRON emission and inverse-Compton scattering can efficiently reduce them to the observed $\mathrm{TeV}$ scale.
[abstract 8 / 33] Yes (score: 4) - Title: Active Galactic Nuclei and STaR fOrmation in Nearby Galaxies (AGNSTRONG). II: Results for Jetted Type-I AGNs with Strong Ionized Gas OutflowsAuthors: Chen Qin, Huynh Anh N. Le, Yongquan Xue, Shifu Zhu, Xiaozhi Lin, Kim Ngan Nhat Nguyen,Comments:Subjects: astro-ph.GACreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
We investigate the correlation between ionized gas outflows, JETs, and STAR FORMATION in a sample of 42 local type-I ACTIVE GALACTIC NUCLEi (AGNs) exhibiting significant [O III] outflows. This study uses both new submillimeter (sub-mm) observations and archival data from the James Clerk Maxwell Telescope. Our analysis, which includes a correction for JET emission in the sub-mm bands, fitting spectral energy distribution, and analyzing spectra, enables us to derive star-formation rates (SFRs) through various methods. By comparing radio power and SFRs, we select a sub-sample of JETted AGNs of which radio emission is mostly from the JETs. We find that JETted AGNs predominantly lie above the main sequence of star-forming galaxies, suggesting a correlation between JET activity and STAR FORMATION. By comparing dust extinction, we demonstrate that JETted AGNs do not have more dust which is the fuel of both STAR FORMATION and AGN activity. Therefore, this correlation is more likely to arise from AGN feedback. We also find that the Eddington ratio does not impact the specific SFRs (sSFRs) of our sample. Additionally, for JETted AGNs, stronger radio emission corresponds to higher sSFRs, suggesting that JET emission may promote STAR FORMATION, i.e., positive feedback. Our results not only shed light on the feedback mechanisms of AGNs but also underscore the complex interplay between BLACK HOLE activity and STAR FORMATION in galaxy evolution.
[abstract 9 / 33] (score: 3) - Title: A binary BLACK HOLE metric approximation from inspiral to mergerAuthors: Luciano Combi, Sean M. Ressler,Comments: Accepted to PRD. The new version includes a comparison between numerical relativity and our metric approximation in the case of circumbinary disk accretionSubjects: gr-qcCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
We present a semi-analytic binary BLACK HOLE (BBH) metric approximation that models the entire evolution of the system from inspiral to merger. The metric is constructed as a boosted Kerr-Schild superposition following post-Newtonian (PN) trajectories at the fourth PN order in the inspiral phase. During merger, we interpolate the binary metric in time to a single BLACK HOLE remnant with properties obtained from numerical relativity {(NR)} fitting formulas. The new metric can model binary BLACK HOLEs with arbitrary spin direction, mass ratio, and eccentricity at any stage of their evolution in a fast and computationally efficient way. We analyze the properties of our new metric and compare it with a full numerical relativity evolution. We show that Hamiltonian constraints are well-behaved even at merger and that the mass and spin measured self-consistently on the BLACK HOLE horizon deviate in average only $\sim 10-5 \%$ compared to the full numerical evolution. We perform General Relativistic MAGNETo-hydrodynamical (GRMHD) simulations for two cases: merging BLACK HOLEs in a uniform gas, and inspiralling BLACK HOLEs accreting from a MAGNETized circumbinary disk. We demonstrate that, in both cases, the properties of the gas, such as the accretion rate, are remarkably similar between the two approaches, with small average differences. We show that the approximate metric has several computational advantages over numerical relativity evolution. The numerical implementation of the metric is now open-source and optimized for numerical work.
[abstract 10 / 33] (score: 3) - Title: Topology of the Superconducting Heart of Neutron Stars: Effects of Microphysics and Gravitational-Wave SignaturesAuthors: Mayusree Das, Armen Sedrakian, Banibrata Mukhopadhyay,Comments: 18 latex pages including 14 figures (14 jpg files) and 1 table; modified and rearranged throughout for clarity; the version accepted for publication in Physical Review DSubjects: astro-ph.HE astro-ph.SR gr-qcCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
We present a general-RELATIVISTIC study of the distribution of proton superconductivity in strongly MAGNETized neutron stars (NSs), using the XNS code to solve the coupled Einstein-Maxwell equations. We investigate equilibrium configurations with both toroidal and poloidal MAGNETic field geometries and incorporate complex many-body effects through microscopically derived proton pairing gaps. The models employ equations of state (EoS) obtained from microscopic many-body theory - including realistic two- and three-body nuclear interactions - as well as from RELATIVISTIC mean-field approaches. We compare superconducting topologies across our collection of EoS and explore the influences of MAGNETic field geometry in stellar models parameterized by central density. Our models confirm the absence of $S$-wave superconductivity in the inner core and, importantly, reveal that non-superconducting regions exhibit complex three-dimensional geometries: doughnut-shaped for toroidal fields and prolate-shaped for poloidal fields -- spatial structures that are inherently absent in one-dimensional analyses. We also compute MAGNETic deformations and ellipticities for several millisecond pulsars (MSPs), estimating their continuous gravitational wave strain. While these MSPs remain undetectable by current detectors, next-generation instruments such as the Einstein Telescope and Cosmic Explorer may detect their signals, opening an observational window into internal superconductivity and internal MAGNETic field of NSs, as well as the fundamental microphysics of dense matter.
[abstract 11 / 33] (score: 3) - Title: BlackTHUNDER: Shedding light on a dormant and extreme little red dot at z=8.50Authors: Gareth C. Jones, Hannah Übler, Roberto Maiolino, Xihan Ji, Alessandro Marconi, Francesco D'Eugenio, Santiago Arribas, Andrew J. Bunker, Stefano Carniani, Stéphane Charlot, Giovanni Cresci, Kohei Inayoshi, Yuki Isobe, Ignas Juodžbalis, Giovanni Mazzolari, Pablo G. Pérez-González, Michele Perna, Raffaella Schneider, Jan Scholtz, Sandro Tacchella,Comments: 24 pages, 13 figures. Accepted for publication in MNRASSubjects: astro-ph.GACreated: 2026-01-14; Updated: 2026-01-16; Datestamp: 2026-01-16
Recent photometric surveys with JWST have revealed a significant population of mysterious objects with red colours, compact morphologies, frequent signs of ACTIVE GALACTIC NUCLEus (AGN) activity, and negligible X-ray emission. These 'Little Red Dots' (LRDs) have been explored through spectral and photometric studies, but their nature is still under debate. As part of the BlackTHUNDER survey, we have observed UNCOVER_20466, one of the most distant LRDs known (z=8.5), with the JWST/NIRSpec IFU. Previous JWST/NIRCam and JWST/NIRSpec MSA observations of this source revealed its LRD nature, as well as the presence of an AGN. Using our NIRSpec IFU data, we confirm that UNCOVER_20466 is an LRD (based on spectral slopes and compactness) that contains an overmassive BLACK HOLE. However, our observed Balmer decrements do not suggest strong dust attenuation, resulting in a lower Hbeta-based bolometric luminosity and Eddington luminosity (~10%) than previously found. This source lies on local relations between M_BH-sigma_* and M_BH-M_Dyn, suggesting that this could be a progenitor of the core of a lower-redshift galaxy. We explore the possible evolution of this source, finding evidence for substantial BLACK HOLE accretion in the past and a likely origin as a heavy seed at high redshift (~10^3Msol). Lyman-alpha emission is strongly detected, implying f_esc,Lya~30%. The extremely high [OIII]4363/Hgamma ratio is indicative of not only AGN photoionization and heating, but also extremely high densities (ne~10^7cm-3), suggesting that this BLACK HOLE at such high redshift may be forming in an ultra-dense protogalaxy.
[abstract 12 / 33] (score: 3) - Title: Faraday DePOLARIZATION Study of a Radio Galaxy Using LOFAR Two-metre Sky Survey: Data Release 2Authors: Samantha Sneha Paul, Abhik Ghosh,Comments: 14 pages, 6 figures, Revised and resubmittedSubjects: astro-ph.COCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
We present a detailed dePOLARIZATION analysis of the RADIO GALAXy \texttt{ILTJ012215.21+254334.8} using polarimetric data from the \textit{LOFAR Two-metre Sky Survey} (LoTSS) Data Release 2 (DR2) catalogue. This source, with \textit{RM} $\sim$ 47 rad m$^{-2}$ and projected linear size $\sim$ 335 kpc at $z \approx 0.05$, serves as a pilot for systematic QU-fitting of unresolved LoTSS sources, building on prior single-target studies that established the need for multi-component Faraday models in complex MAGNETo-ionic media. Fitting five dePOLARIZATION models to the LoTSS HBA (120-168 MHz) fractional POLARIZATION spectra reveals a decisively preferred three-component model (one Faraday-thin instrumental leakage, plus two external Faraday dispersions), demonstrating that LoTSS data alone can constrain moderate Faraday complexity in typical DR2 galaxies. Our results highlight turbulence and inhomogeneity in the foreground MAGNETo-ionic medium and outline a path for population studies of LoTSS FR-I sources.
[abstract 13 / 33] (score: 3) - Title: The X-Ray Dot: Exotic Dust or a Late-Stage Little Red Dot?Authors: Raphael E. Hviding, Anna de Graaff, Hanpu Liu, Andy D. Goulding, Yilun Ma, Jenny E. Greene, Leindert A. Boogaard, Andrew J. Bunker, Nikko J. Cleri, Marijn Franx, Michaela Hirschmann, Joel Leja, Rohan P. Naidu, Jorryt Matthee, David J. Setton, Hannah Übler, Giacomo Venturi, Bingjie Wang,Comments: 21 pages, 7+2 Figures, 1+3 Tables, submitted to AJL. Comments welcome!Subjects: astro-ph.GACreated: 2026-01-14; Updated: 2026-01-16; Datestamp: 2026-01-16
JWST's "Little Red Dots" (LRDs) are increasingly interpreted as ACTIVE GALACTIC NUCLEi (AGN) obscured by dense thermalized gas rather than dust as evidenced by their X-ray weakness, blackbody-like continua, and Balmer line profiles. A key question is how LRDs connect to standard UV-luminous AGN and whether transitional phases exist and if they are observable. We present the "X-Ray Dot" (XRD), a compact source at $z=3.28$ observed by the NIRSpec WIDE GTO survey. The XRD exhibits LRD hallmarks: a blackbody-like ($T_{\rm eff} \simeq 6400\,$K) red continuum, a faint but blue rest-UV excess, falling mid-IR emission, and broad Balmer lines ($\rm FWHM \sim 2700-3200\,km\,s^{-1}$). Unlike LRDs, however, it is remarkably X-ray luminous ($L_\textrm{2$-$10$\,$keV} = 10^{44.18}\,$erg$\,$s$^{-1}$) and has a continuum inflection that is bluewards of the Balmer limit. We find that the red rest-optical and blue mid-IR continuum cannot be reproduced by standard dust-attenuated AGN models without invoking extremely steep extinction curves, nor can the weak mid-IR emission be reconciled with well-established X-ray--torus scaling relations. We therefore consider an alternative scenario: the XRD may be an LRD in transition, where the gas envelope dominates the optical continuum but optically thin sightlines allow X-rays to escape. The XRD may thus provide a physical link between LRDs and standard AGN, offering direct evidence that LRDs are powered by supermassive BLACK HOLEs and providing insight into their accretion properties.
[abstract 14 / 33] (score: 3) - Title: Gravitational lensing beyond the eikonal approximationAuthors: Emma Bruyère, Cyril Pitrou,Comments: 29 pages, 5 figuresSubjects: gr-qcCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
Waves propagating through a gravitational potential exhibit wave-optics effects when their wavelength is not significantly smaller than the lensing scales. We study the propagation of a scalar wave, governed by the Klein-Gordon equation in curved spacetime, to focus on effects on amplitude and phase, while leaving aside the issue of wave POLARIZATION which affects electroMAGNETic and gravitational waves. Using the Newman-Penrose formalism, we obtain the first corrections beyond the geometric optics in the expansion in the inverse frequency. In vacuum, that is for Weyl tensor lensing, there is no wave effect at first order in $G$ and wave effects start at order $G^2$. Conversely, if the wave travels through a non-vanishing matter density, the first corrections start at order $G$. We check these analytic results by solving numerically the equations dictating the evolution of the corrections either in the vicinity of a Schwarzschild BLACK HOLE or through a transparent star.
[abstract 15 / 33] (score: 3) - Title: Long Period Transients (LPTs): a comprehensive reviewAuthors: Nanda Rea, Natasha Hurley-Walker, Manisha Caleb,Comments: 23 pages, 12 figures, 3 tables. Under review at the Journal of High Energy Astrophysics. Comments welcomeSubjects: astro-ph.HE astro-ph.SRCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
Long Period Transients (LPTs) are a recently identified class of sources characterized by periodic radio bursts lasting seconds to minutes, with flux densities that might reach several tens of Jy. These radio bursts repeat with periodicity from minutes to hours, and they exhibit strong POLARIZATION and transient activity periods. To date, about 12 such sources have been identified, which might encompass the same or different physical scenarios. Proposed explanations include binary systems with a white dwarf and a low-mass star companion, slow-spinning MAGNETars, highly MAGNETized isolated white dwarfs, and other exotic objects. In a few cases the optical counterpart indeed points toward a white dwarf with a low-mass companion, while in other cases, transient X-ray emission was detected, very common in MAGNETars. However, despite being able to reproduce partially some of the characteristics of LPTs, all the proposed scenarios find difficulty in explaining the exact physical origin of their bright, highly polarized and periodic radio emission. We review here the state-of-the-art in the observations and interpretation of this puzzling class of radio transients.
[abstract 16 / 33] (score: 3) - Title: From Weibel seeds to collisionless dynamos beyond pair-plasmasAuthors: Lise Hanebring, James Juno, Ammar Hakim, Jason M. TenBarge, Istvan Pusztai,Comments:Subjects: physics.plasm-ph astro-ph.COCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
Bridging the spatiotemporal scales of MAGNETic seed field generation and subsequent dynamo amplification in the weakly collisional intracluster medium presents an extreme numerical challenge. We perform collisionless turbulence simulations with initially unMAGNETized electrons that capture both MAGNETic seed generation via the electron Weibel instability and the ensuing dynamo amplification. Going beyond existing pair-plasma studies, we use an ion-to-electron mass ratio of 100 for which we find electron and ion dynamics are sufficiently decoupled. These simulations are enabled by the 10-moment collisionless fluid solver of Gkeyll, which evolves the full pressure tensor for all species. The electron heat-flux closure regulates pressure isotropization and effectively sets the MAGNETic Reynolds number. We investigate how the strength of of the closure influences the transition between a regime reminiscent of previous kinetic pair-plasma simulations and a more MHD-like dynamo regime.
[abstract 17 / 33] (score: 3) - Title: Canonical Vorticity Perspective on Magnetogenesis: Unifying Weibel, Biermann, and BeyondAuthors: Modhuchandra Laishram, Young Dae Yoon,Comments: Submitted to RMPP, 16-pages and 9-figuresSubjects: physics.plasm-phCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
We briefly review the current status of MAGNETogenesis, a cross-disciplinary field that bridges cosmology and plasma physics, studying the origin of MAGNETic fields in the universe. We formulate a canonical vorticity framework to investigate kinetic plasma physics-based MAGNETogenesis processes in a collisionless plasma. By considering canonical vorticity, a weighted sum of the fluid vorticity and the MAGNETic field as the canonical variable, this framework unifies several MAGNETogenesis processes, including the Biermann battery, the Weibel instability, and predicts several new pressure tensorial configurations as the fundamental source of self-generated MAGNETic field and vorticity in plasma. The framework is further extended to RELATIVISTIC regime where an additional source of canonical vorticity, termed as kineclinicity effect, is identified. The theoretical predictions are systematically validated using particle-in-cell simulations, highlighting their implications for laboratory and astrophysical plasma environments.
[abstract 18 / 33] (score: 3) - Title: Origins of the UV continuum and Balmer emission lines in Little Red Dots: observational validation of dense gas envelope models enshrouding the AGNAuthors: Yoshihisa Asada, Kohei Inayoshi, Qinyue Fei, Seiji Fujimoto, Chris Willott,Comments: Submitted to ApJL. Comments are welcomeSubjects: astro-ph.GACreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
We present a statistical study on the origins of the UV continuum and narrow/broad emission lines in little red dots (LRDs), a newly discovered class of ACTIVE GALACTIC NUCLEi (AGNs). Leveraging all archived JWST/NIRSpec data, we build a sample of 28 spectroscopically-confirmed LRDs at $5
[abstract 19 / 33] (score: 2) - Title: Collisional whistler instability and electron temperature staircase in inhomogeneous plasmaAuthors: N. A. Lopez, A. F. A. Bott, A. A. Schekochihin,Comments: 43 pages (33 pages main article), 15 figures, 8 appendices. Updated to published version, involving significant changes compared to previous versionSubjects: physics.plasm-phCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
High-beta MAGNETized plasmas often exhibit anomalously structured temperature profiles, as seen from galaxy cluster observations and recent experiments. It is well known that when such plasmas are collisionless, temperature gradients along the MAGNETic field can excite whistler waves that efficiently scatter electrons to limit their heat transport. Only recently has it been shown that parallel temperature gradients can excite whistler waves also in collisional plasmas. Here we develop a Wigner--Moyal theory for the collisional whistler instability starting from Braginskii-like fluid equations in a slab geometry. This formalism is necessary because, for a large region in parameter space, the fastest-growing whistler waves have wavelengths comparable to the background temperature gradients. We find additional damping terms in the expression for the instability growth rate involving inhomogeneous Nernst advection and resistivity. They (i) enable whistler waves to re-arrange the electron temperature profile via growth, propagation, and subsequent dissipation, and (ii) allow non-constant temperature profiles to exist stably. For high-beta plasmas, the marginally stable solutions take the form of a temperature staircase along the MAGNETic field lines. The electron heat flux can also be suppressed by the Ettingshausen effect when the whistler intensity profile is sufficiently peaked and oriented opposite the background temperature gradient. This mechanism allows cold fronts without MAGNETic draping, might reduce parallel heat losses in inertial fusion experiments, and generally demonstrates that whistler waves can regulate transport even in the collisional limit.
[abstract 20 / 33] (score: 2) - Title: Rates of Strongly Lensed Tidal Disruption EventsAuthors: E. Mamuzic, T. Ryu, S. H. Suyu, K. Szekerczes, S. Huber, L. Dai, M. Oguri,Comments: 14 pages, 13 figures, accepted by Astronomy & Astrophysics (A&A)Subjects: astro-ph.HE astro-ph.COCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
In the coming years, surveys such as the Rubin Observatory's Legacy Survey of Space and Time (LSST) are expected to increase the number of observed Tidal Disruption Events (TDEs) substantially. We employ Monte Carlo integration to calculate the unlensed and lensed TDE rate as a function of limiting magnitude in $u$, $g$, $r$, and $i$-bands. We investigate the impact of multiple luminosity models, BLACK HOLE mass functions (BHMFs), and flare temperatures on the TDE rate. Notably, this includes a semi-analytical model, which enables the determination of the TDE temperature in terms of BLACK HOLE (BH) mass. We predict the highest unlensed TDE rate to be in $g$-band. It ranges from $16$ to $5,440\;\mathrm{yr}^{-1}\;(20,000\;\mathrm{deg}^2)^{-1}$ for the Zwicky Transient Facility, being more consistent with the observed rate at the low end. For LSST, we expect a rate in $g$-band between $3,580$ and $82,060\;\mathrm{yr}^{-1}\;(20,000\;\mathrm{deg}^2)^{-1}$. A higher theoretical prediction is understandable, as we do not consider observational effects such as completeness. The unlensed and lensed TDE rates are insensitive to the redshift evolution of the BHMF, even for LSST limiting magnitudes. The best band for detecting lensed TDEs is also $g$-band. Its predicted rates range from $0.43$ to $15\;\mathrm{yr}^{-1}\;(20,000\;\mathrm{deg}^2)^{-1}$ for LSST. The scatter of predicted rates reduces when we consider the fraction of lensed TDEs; that is, a few in ten thousand TDEs will be lensed. Despite the large scatter in the rates of lensed TDEs, our comprehensive considerations of multiple models suggest that lensed TDEs will occur in the $10$-year LSST lifetime, providing an exciting prospect for detecting such events. We expect the median redshift of a lensed TDE to be between $1.5$ and $2$. In this paper, we additionally report on lensed TDE properties, such as the BH mass and time delays.
[abstract 21 / 33] (score: 2) - Title: Charged Scalar Field at Future Null Infinity via Nonlinear Hyperboloidal EvolutionAuthors: João D. Álvares, Alex Vañó-Viñuales,Comments: 9 pages, 8 figuresSubjects: gr-qcCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
Quasinormal modes and power-law late-time decay tails of a charged scalar field in a charged BLACK HOLE background have been studied, but never in the fully non-linear regime, as far as we know. In this paper, we study the dependence of these properties on the charges of scalar field and BLACK HOLE. For the quasinormal modes, a fit of the spherical fundamental mode is shown for the purely uncharged case and compared to the charged one. We also see for the first time the transition from gravitational decay to pure electroMAGNETic decay, and show disagreement with the oscillation frequency between real and imaginary parts of the scalar field prescribed in the literature. Full non-linear evolutions of hyperboloidal slices in spherical symmetry were used to obtain our results, allowing for the extraction of signals at future null infinity.
[abstract 22 / 33] (score: 2) - Title: The Cosmic Neutrino Background is within Reach of Future Neutrino TelescopesAuthors: Gonzalo Herrera, Shunsaku Horiuchi, Xiaolin Qi, Ian M. Shoemaker,Comments: 7+5 pages, 3+1 figuresSubjects: hep-ph astro-ph.CO astro-ph.HECreated: 2026-01-14; Updated: 2026-01-16; Datestamp: 2026-01-16
The cosmic neutrino background (C$ν$B) can be boosted to high energies due to scatterings with energetic COSMIC RAYs (CRs) across cosmological scales. Previous calculations focused on neutral current incoherent and coherent elastic scatterings of cosmic-ray protons off relic neutrinos. However, charged current interactions and deep inelastic scatterings are also expected to occur, which enhances the boosted relic neutrino fluxes on Earth. Here, we compute the \textit{total} diffuse boosted cosmic neutrino background (DBC$ν$B) arising from CRs at all redshifts in the Universe, accounting for neutral current and charged current elastic and deep inelastic scatterings. We find that IceCube already places an upper limit on the cosmic neutrino background overdensity in cosmological scales of ~$\mathcal{O}(100-1000)$ at $E_ν=10^{10}$ GeV, for a lightest neutrino mass of $m_ν \gtrsim 0.1$ eV. We further show that IceCube-Gen2 could test $\mathcal{O}(1-10)$ C$ν$B overdensities, and the combination of $10$ future neutrino telescopes with similar sensitivity would allow us to test the $Λ$CDM expected C$ν$B density for a lightest neutrino mass compatible with the KATRIN bound.
[abstract 23 / 33] (score: 2) - Title: Stellar-wind Fueled Accretion onto Sagittarius A* in the Presence of a Nuclear Star ClusterAuthors: Edward Skrabacz, Lena Murchikova, Sean M. Ressler, Asad Ukani, Siddhant Solanki,Comments: 8 pages, 4 figures. Comments are welcomeSubjects: astro-ph.HE astro-ph.GACreated: 2026-01-14; Updated: 2026-01-16; Datestamp: 2026-01-16
The Milky Way's Galactic Center hosts the BLACK HOLE Sagittarius A* (Sgr A*), which provides us with a close-up view into supermassive BLACK HOLE accretion and feedback. Recent works have shown that the winds from $\sim 30$ Wolf-Rayet (WR) stars orbiting Sgr A* at about 4 arcsec are important contributors to feeding the supermassive BLACK HOLE. A nuclear star cluster (NSC) with a mass of several $10^6 \, \text{M}_\odot$, of which $10^6 \, \text{M}_\odot$ is within 1 pc, also surrounds Sgr A*. The NSC contributes to the gravitational potential in the Galactic Center, affecting the orbits of the WR stars and their stellar winds. In this work, we examine the effects that the NSC has on the accretion of these stellar winds onto Sgr A* which have previously been neglected. We find that, on the parsec scale, the effect from the gravitational potential of the NSC is negligible on the wind-fed accretion flow, validating the existing simulations used in the literature.
[abstract 24 / 33] (score: 2) - Title: Simulating the photospheric to coronal plasma using MAGNETohydrodynamic characteristics III: validation including gravity, flux emergence, and an eruptionAuthors: Lucas A. Tarr, N. Dylan Kee, James E. Leake, Mark G. Linton, Peter W. Schuck,Comments: 17 pages, 8 figures. Accepted for publication in ApJSubjects: astro-ph.SRCreated: 2026-01-14; Updated: 2026-01-16; Datestamp: 2026-01-16
Solar eruptions arise from instabilities or loss of equilibria in the solar atmosphere, but routinely inferring the precise MAGNETic and plasma properties that lead to eruptions is not currently practical using synoptic solar observations. Data driven simulations offer an appealing alternative. We test our boundary data-driven MAGNETohydrodynamic (MHD) approach, based on the method of characteristics, on a simulation that includes full MHD, a stratified atmosphere, and the emergence of a model solar MAGNETic active region, from the photosphere upwards. The driven simulation is tested against a larger, ab initio ``Ground Truth'' simulation that extends downward into the convection zone. Our driven simulation accurately reproduces the dynamic emergence of the active region above the photosphere, the formation of key topological features throughout the corona, and the subsequent eruption of mass and MAGNETic field. The total emerged energy matches to better than one percent, the ratio of emerged to eruptive energy is $\approx2\%$, and the actual values of each energy term agree to within $10\%$ between the two cases. Crucially, the data injection cadence, when properly scaled, matches the cadence of synoptic observations of the Sun's surface MAGNETic field, and is three to four orders of magnitude longer than the inherent CFL time step of the simulations. The stability of the code and fidelity of the results over an entire active region lifetime, from emergence to eruption, strongly suggests that our method will produce reliable results when driven using solar synoptic observations from existing and anticipated ground and spaced based observatories.
[abstract 25 / 33] (score: 2) - Title: Magnetic Pumping: Plasma Heating to Particle AccelerationAuthors: Mikhail Malkov, Immanuel Jebaraj,Comments: 12 pages, 8 figuresSubjects: astro-ph.HECreated: 2026-01-14; Updated: 2026-01-16; Datestamp: 2026-01-16
One of the earliest mechanisms proposed for plasma heating was MAGNETic pumping (MP). However, its significance for astrophysical phenomena, including particle acceleration, has yet to be appreciated. MP-energized particles tap energy from MAGNETic-field oscillations. A particle's momentum component perpendicular to the local B-field increases during field growth by virtue of the adiabatic invariant $p_{\perp}^{2}/B=const$. The gained $p_{\perp}$ is then partially scattered elastically into the parallel momentum, $p_{\parallel}$, with $p^{2}=p_{\parallel}^{2}+p_{\perp}^{2}=const$, thereby retaining some fraction of the gained energy before the field decreases to its minimum. This scattering breaks the reversibility of energy exchange between particles and oscillating MAGNETic fields, thereby increasing the particle energy after each MP cycle. Field oscillations are often assumed to be sinusoidal, and the resulting MP is treated perturbatively. These simplifications restrict astrophysical applications, leaving objects with strong MAGNETic perturbations outside the scope of adequate treatment. We develop a nonperturbative approach to MP that is suitable for a broad spectrum of MAGNETic turbulence. The treatment comprises two steps. The first step is common: converting a kinetic equation into an infinite hierarchy of moments of the particle distribution function. The second step is new in MP treatments: we find an exact closure at an arbitrary level of the moment system. The heating is treated exactly at the second-moment closure. Particle acceleration generally requires a higher-level closure to determine the power-law index and the maximum energy of accelerated particles. We propose a method for extracting these crucial acceleration data from the second moment for a broadband random field.
[abstract 26 / 33] (score: 2) - Title: Dynamics of Apsidal Motion in Non-Synchronous Binary Pulsars Coupled Orbit and Spin EvolutionAuthors: Ali Taani,Comments: Published by Astrophysics and Space Science, 2025, 370, (11), 128Subjects: astro-ph.HE astro-ph.SRCreated: 2026-01-14; Updated: 2026-01-16; Datestamp: 2026-01-16
The apsidal motion of a non-synchronous binary pulsar serves as a valuable probe of RELATIVISTIC gravity, stellar stricture, and dynamical evolution of close binary systems, In this study, we investigate the combined influence of general relativity, stellar oblateness and tidal interaction on the apsidal motion of three binary pulsars: 1913+16, J0737-3039A/B, and J0621+1002. Zahn's tidal equations \cite{1977A&A....57..383Z, 1989A&A...220..112Z} were employed for numerical integrations to describe tidal effects and their role in orbital and spin evolution. We estimated the timescales for tidal synchronization and orbital circularization for each system. The results indicate that tidal effects play only a minor role in orbital decay compared with energy loss due to gravitational wave emission. This is evident in the compact system PSR 1913+16, where the orbital period decreases by approximately 76.5 $μ$s/yr as a result of gravitational radiation. The double pulsar J0737-3039A/B exhibits faster orbital evolution, with synchronization occurring in about 8.4$\times10{^3}$ years, whereas the wider system J0621+1002 shows negligible orbital change over timescales exceeding 10$^{10}$ years. The simulations demonstrate clear trends of decreasing semi-major axis and eccentricity, accompanied by an increase in spin rate among the binary pulsars studied. The derived apsidal motion constants [$k\simeq0.1$] are consistent with theoretical expected values, and the corresponding tidal friction times (between a few hours to several days) agree well with theoretical predication. These results emphasize the dominant role of RELATIVISTIC effects in neutron star binaries and highlight the importance of including gravitational-wave terms long-term orbital evolution
[abstract 27 / 33] (score: 2) - Title: Effects of parallel MAGNETic fields on sheaths near biased electrodes in a highly collisional Z-pinch plasmaAuthors: C. R. Skolar, B. Srinivasan,Comments: 10 pages, 6 figuresSubjects: physics.plasm-phCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
Sheath formation near biased electrodes in MAGNETic fields parallel to the wall is an understudied topic, especially within the context of Z-pinch fusion experiments. We perform 1X-2V Boltzmann-Poisson simulations of an axial cut at the pinch radius of a Z-pinch plasma between two biased electrodes with a MAGNETic field parallel to the wall. The collision frequencies are artificially increased to enhance thermalization of the plasma in the smaller simulation domain versus the actual experiment size; this increases the perpendicular mobility and partially de-MAGNETizes the ions resulting in non-monotonic sheath profiles with the potential increasing away from the wall to a peak before decaying. A classical sheath forms within an electron gyroradius from the wall not due to the natural thermal motion of the electrons, but due to the MAGNETized electrons gyrating into the wall; therefore, the sheath structure does not significantly change with bias potential or between electrodes. With increasing bias potential, a current is induced perpendicular to the wall due to changes in ion flow, differing from unMAGNETized cases where current is induced by changes in electron flow. The MAGNETic field acts as a high resistivity with the perpendicular current density being three orders of magnitude lower than unMAGNETized theoretical predictions. There is, however, significant flow parallel to the wall from the force balance between the pressure tensor and Lorentz force. These parallel flows induce a parallel current density three orders of magnitude larger than the perpendicular current density.
[abstract 28 / 33] (score: 2) - Title: Updated electrical design of the Diagnostic Neutral Beam Injector in RFX-mod2Authors: Marco Barbisan, Bruno Laterza, Luca Cinnirella, Lionello Marrelli, Federico Molon, Simone Peruzzo, Enrico Zampiva,Comments: 7 pages, 11 figures. Preprint submitted to IEEE TPS, following the PPPS conference (15-20 June 2025, Berlin)Subjects: physics.plasm-phCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
The Diagnostic Neutral Beam Injector of the RFX-mod2 experiment (Consorzio RFX, Padova) is expected to provide novel and significant information about the Reversed Field Pinch confinement of fusion plasmas. The injection of the hydrogen beam in the plasma will allow Charge Exchange Recombination Spectroscopy (CXRS) and Motional Stark Effect diagnostics (MSE) to measure several quantities: ion speed, ion temperature, impurity content, intensity and pitch of the MAGNETic field. The DNBI is of particular importance for allowing the determination of these quantities at the core of the plasma. The present DNBI, built by the Budker Institute of Plasma Physics, features an arc discharge H+ source, coupled to a 4-grid 50 keV acceleration system. The 50 ms, 5 A ion beam is neutralized by charge exchange by means of a gas target; residual ions are then deflected by a MAGNETic field before injection in the torus chamber. The beam can be modulated at maximum 250 Hz. The DNBI will undergo extraordinary maintenance and a structural upgrade to improve its reliability and safety. This contribution presents the latest upgrades of the electrical plants and of the control system of the DNBI.
[abstract 29 / 33] (score: 2) - Title: Design, Fabrication and Testing of a D-Shaped High Temperature Superconducting MagnetAuthors: Upendra Prasad, Mahesh Ghate, Piyush Raj, Deven Kanabar, Pankaj Varmora, Swati Roy, Arun Panchal, Dhaval Bhavsar, Anees Bano, Nitish Kumar, Bhadresh Parghi, Akhilesh Yadav, Mohd. Umer, Vijay Vasava, Raton Mandal, Rajkumar Ahirwar, Megha Thaker,Comments:Subjects: physics.acc-ph physics.plasm-phCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
High-temperature technical superconductors are potential candidates for compact and high-field tokamak MAGNETs. The demand for higher fusion power can be met with an on-axis high MAGNETic field due to toroidal MAGNETs. An R&D activity has been initiated at the Institute for Plasma Research, India, to develop a compact D-shaped superconducting MAGNET utilizing REBCO high-temperature superconducting tapes. Under this initiative, a toroidal configuration with a major radius of 0.42 m, consisting of eight D-shaped, four poloidal field, and a central solenoid high-temperature superconducting MAGNETs producing an on-axis toroidal MAGNETic field of 0.23 T has been conceptualized. The fabrication feasibility of a D-shaped coil for this toroidal configuration also envisaged using stacked high-temperature superconducting cable. In this paper, we report the design of a compact D-shaped coil, the fabrication of a long length HTS cable, a winding pack, and its integration with a cryogenic casing and vacuum enclosure. The winding pack terminations, joints, its interfacing with the power supply, and performance testing are also reported in this paper.
[abstract 30 / 33] (score: 2) - Title: Distinguishing Quantum Matter by Gravity with Differential Scattering Cross Section at Tree LevelAuthors: Xue-Nan Chen,Comments:Subjects: gr-qcCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
The definition of weak equivalence principle of quantum matter is an open problem at present. In order to reflect the probability of quantum system in the quantum version of weak equivalence principle, we proposed a quantum weak equivalence principle based on differential scattering cross section at tree level, that is, the differential scattering cross section does not depend on the mass and properties of the scattered particles when the target particles take the large mass limit. This version of the quantum equivalence principle we proposed will be broken by the spin properties of quantum matter. In the non-RELATIVISTIC case, the difference of differential scattering cross sections of scattered particles with different spin properties scattered by target particles is mainly reflected in the order of $ \mathcal O (p _ {\mathrm{cm}} ^2) $. In the RELATIVISTIC case , we studied the asymptotic behavior of differential scattering cross sections at small angles. When the target particles are scalar particles, the difference of light particles with different spin properties is mainly reflected in the $ \mathcal O (1/θ^2) $ order. When the target particles are Dirac particles, the difference of light particles with different spin properties is mainly reflected in the $ \mathcal O (1/θ^4) $ order. The POLARIZATION of differential scattering cross section when scattered particles are Dirac particles is investigated. The result of the degree of POLARIZATION depends on the POLARIZATION direction of the incident particles.
[abstract 31 / 33] (score: 2) - Title: Active interrogation of underground piezoelectric fabrics using high energy muon beams propagating across seismogenic faultsAuthors: L. Serafini, A. Bacci, L. Bandiera, F. Broggi, I. Drebot, A. Frazzitta, A. M. Marotta, G. Muttoni, G. Paternò, V. Petrillo, M. Rossetti Conti, A. R. Rossi, S. Samsam, M. Voltolini, M. Zucali,Comments:Subjects: physics.acc-phCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
In this paper we extend a previous analysis of a newly conceived technique based on active interrogation of tectonic stress evolution in regions hosting active seismogenic faults. The aim is to monitor and detect stable and reliable precursor signals on an adequate time scale, well before an earthquake event, that can play a crucial role in activating alarms for civil protection systems. The precursor signal relies on continuous measurements of the time evolution of tectonic stress, obtained by interrogating underground, with a high energy collimated muon beam, the piezoelectric fabrics present in quartz rich granite like rocks surrounding a known seismogenic fault in the Earth crust. Beam propagation through the rock across the active fault conveys to a detector at the exit of the traversal information on the amplitude of the piezoelectric field, which scales with the tectonic stress applied to quartz crystals embedded in the rock. The system, named ERMES (Earthquake Reconnaissance using Muon beam Evolution in Silicon dioxide), differs from other techniques under study detecting electroMAGNETic signals generated by piezoelectricity outside the Earth crust, as it probes piezoelectric effects directly inside the source region of the associated electroMAGNETic field, namely the near field within quartz crystals rather than the far field in open space. We present a focused analysis of muon beam manipulation after rock traversal and before detection using a newly conceived muonic lens, and we explore the maximum rock penetration capability of a high energy muon beam, reaching about 3 km of rock thickness for a 10 TeV beam. Owing to the peculiarity of muon propagation through such kilometer scale targets, we cross checked previous FLUKA Monte Carlo simulations with Geant4 to clarify the secondary muons role generated by primary muon interactions in solid matter over long propagation lengths.
[abstract 32 / 33] (score: 2) - Title: Measuring the Coronal Magnetic Field with 2D Coronal Seismology: A Forward-Modeling ValidationAuthors: Zihao Yang, Sarah Gibson, Matthias Rempel, Giuliana de Toma,Comments: 17 pages, 10 figures, accepted for publication in ApJSSubjects: astro-ph.SRCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
In recent years, a two-dimensional (2D) coronal seismology technique applied to spectral-imaging data from the Coronal Multi-channel Polarimeter (CoMP) and UCoMP has enabled routine measurement of the global coronal MAGNETic field. The technique combines coronal transverse wave phase speed from Doppler measurements with electron densities from the Fe \sc{xiii}\rm{} 10798/10747 Å intensity ratio to infer the MAGNETic field strength, while the wave propagation directions from Doppler measurements trace the MAGNETic field direction. To validate the accuracy and robustness of this method, we use forward modeling of a MURaM simulation that produces open and closed MAGNETic structures with excited waves. From the synthetic Doppler velocity, Fe \sc{xiii}\rm{} infrared line intensities, and linear POLARIZATION signals, we apply the 2D coronal seismology technique to estimate the MAGNETic field strength and direction. A comparison with the simulation ground truth shows close agreement, indicating that the technique can recover the line-of-sight emissivity-weighted MAGNETic field direction and strength with high accuracy. We also perform a parameter-space analysis to quantify sensitivities of the method to parameter choice. These findings provide practical guidance for CoMP/UCoMP-like analysis and demonstrate that 2D coronal seismology can deliver reliable, LOS emissivity-weighted measurements of the coronal MAGNETic field from coronal wave observations.
[abstract 33 / 33] (score: 2) - Title: MHD modelling of open flux evolution around solar maximum by coronal model COCONUTAuthors: Haopeng Wang, Stefaan Poedts, Andrea Lani, Luis Linan, Tinatin Baratashvili, Hyun-Jin Jeong, Rayan Dhib, Quentin Noraz, Wenwen Wei, Mahdi Najafi-Ziyazi, Junyan Liu, Hao Wu, Rui Zhuo, José Miguel Luzia Murteira, Ketevan Arabuli, Brigitte Schmieder, Jasmina Magdalenić Zhukov,Comments: 12 pages, 7 figuresSubjects: astro-ph.SRCreated: 2026-01-15; Updated: 2026-01-16; Datestamp: 2026-01-16
To evaluate impact of temporal evolution and commonly used harmonic filtering of MAGNETograms, and the empirically defined oversimplified heating source terms on open-field distributions, we use a series of hourly-updated MAGNETograms, preprocessed by the 10th- and 50th-order filtered PF solvers, to drive COCONUT, configured with different heating prescriptions, to mimic coronal evolutions during CRs 2282 and 2283. We evaluate the simulated open MAGNETic flux at 1.01~$R_s$, 3~$R_s$, and 0.1~AU, and compare them with interplanetary observations. The results show that the simulated unsigned open flux evaluated near the solar surface can be comparable to that derived from interplanetary in situ observations. However, in low corona, numerous small-scale closed-field MAGNETic structures introduce MAGNETic polarity inversion interfaces within the open field, cancelling part of the open field near these interfaces during the volume-integration procedure of the finite-volume method. Consequently, the simulated unsigned open flux can be reduced by up to 45% at 0.1~AU and decreases more rapidly in the low corona. The results also indicate that moderate adjustments to the heating source term can effectively regulate the magnitude of the unsigned open MAGNETic flux. Preprocessing the initial MAGNETogram by a PF solver with limited spherical harmonics can reduce the open flux in the low corona and alter the distribution of open-field regions, but has little effect on the total unsigned open flux at larger heliocentric distances. The ratio of the maximum to minimum open unsigned MAGNETic flux can reach 1.4 within a single solar maximum CR. These findings highlight the necessity of considering finer grid resolution around MAGNETic polarity inversion interfaces, more realistic heating mechanisms, and the time-evolving regime of MHD coronal modelling when further addressing the ``open flux problem".
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