Current date: 2026-05-14
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Datestamp limit: 2026-05-14 (0 days ago)
Created/updated limit: 2026-05-07 (7 days ago)
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Scoring abstracts
Number of records retrieved: 691
Keyword score statistics
score 9 -- 1 abstracts
score 8 -- 1 abstracts
score 7 -- 1 abstracts
score 6 -- 2 abstracts
score 5 -- 5 abstracts
score 4 -- 3 abstracts
score 3 -- 6 abstracts
score 2 -- 17 abstracts
in total -- 36 abstracts
Articles that appeared on 2026-05-14
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[abstract 1 / 36] Wow! (score: 9)
- Title: Tracking down the broadband polarimetric properties of PG 1553+113Authors: Riccardo Middei, Svetlana G. Jorstad, Alan P. Marscher, Ioannis Liodakis, Matteo Perri, Alessandro Maselli, Stefano Ciprini, Emanuele Nardini, Simonetta Puccetti, Laura Di Gesu, Iván Agudo, Dawoon E. Kim, Ioannis Myserlis, A. Trindade Falcão, D. Ł. Król, Lucio A. Antonelli, Tommaso Aniello, Pouya M. Kouch, Kari Nilsson, Elina Lindfors, Tapio Pursimo, Francisco José Aceituno, Víctor Casanova, Gabriel Emery, Juan Escudero Pedrosa, Jorge Otero-Santos, Alfredo Sota, Vilppu Piirola, George A. Borman, Tatiana S. Grishina, Vladimir A. Hagen-Thorn, Evgenia N. Kopatskaya, Elena G. Larionova, Daria A. Morozova, Sergey S. Savchenko, Ekaterina V. Shishkina, Ivan S. Troitskiy, Yulia V. Troitskaya, Andrey A. Vasilyev, Alexey V. Zhovtan, Petra Benke, Lena Debbrecht, Julia Eich, Florian Eppel, Andrea Gokus, Steven Hämmerich, Jonas Heßdörfer, Matthias Kadler, Dana Kirchner, Georgios F. Paraschos, Florian Rösch, Wladislaw Schulga, Mark Gurwell, Garrett Keating, Ramprasad Rao, Emmanouil Angelakis, Alexander Kraus, Beatriz Agís-González, Dmitry Blinov, Anastasia Glykopoulou, Sara Capecchiacci, Alberto Floris, Panagiotis Fotis, Alkmini Koukoutsi, John A. Kypriotakis, Dimitrios A. Langis, Dimitrios Rompogiannakis, Aristeidis Polychronakis, Vasiliki Tsioupli, Stavros Vogiatzis, Orestis Zoumpoulakis, Sumie Tochihara, Ryo Imazawa, Mahito Sasada, Yasushi Fukazawa, Koji S. Kawabata, Makoto Uemura, Tsunefumi Mizuno, Tatsuya Nakaoka, Hiroshi Akitaya, Takahiro Akai,Comments: accepted for publication in ApJ, 20 pages, 7 figures, and 4 tablesSubjects: astro-ph.HE hep-phCreated: 2026-05-12; Updated: 2026-05-14; Datestamp: 2026-05-14
We report on a nine-month monitoring campaign of the BLAZAR PG 1553+113, relying on three observations carried out in 2025 with the Imaging X-ray Polarimetry Explorer (IXPE) and supported by multi-wavelength facilities. The source displayed pronounced variability across the electroMAGNETic spectrum, with X-ray flux changes by up to a factor of $\sim5$ and complex evolution of the optical POLARIZATION properties, including one of the largest (exceeding $150^{\circ}$) and fastest rotations in the electric vector position angle (EVPA) ever recorded. This swing of the EVPA was also accompanied by a temporary drop of the optical POLARIZATION degree to nearly zero. Significant X-ray POLARIZATION was observed during the third IXPE pointing, with a POLARIZATION degree $Π_{\rm X}\,=(\,18.4\,\pm\,5.8)\%$ and $Ψ_{\rm X}\,=\,74^{\circ} \pm 9^{\circ}$ in the 2--8~keV band, while only upper limits were obtained in the first two epochs. The optical data show that the second IXPE observation occurred shortly after a dramatic optical POLARIZATION event characterized by a rapid EVPA swing and strong dePOLARIZATION. Two possible scenarios may explain the broadband polarimetric behavior: (i) the superposition of two emitting regions with nearly orthogonal MAGNETic field configurations and variable relative contributions, and (ii) the interaction of a single emitting region with a shock that temporarily reorders the MAGNETic field. In both cases, the data support a picture in which the X-ray and optical emissions arise from closely related but not strictly co-spatial regions within a dynamically evolving, MAGNETically structured JET.
[abstract 2 / 36] Wow! (score: 8) - Title: Jets from Scratch: A 3D Dynamo Origin of Long Gamma-Ray Burst JetsAuthors: Ho-Sang Chan, Ore Gottlieb, Jonatan Jacquemin-Ide, Matteo Cantiello, Mathieu Renzo,Comments: 22 pages, 8 figures, submitted to APJLSubjects: astro-ph.HE gr-qcCreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
The origin of the large-scale poloidal MAGNETic field required to power RELATIVISTIC JETs in collapsars remains uncertain. While such a field may be inherited during PNS collapse, the efficiency of this process is unclear, motivating an in situ mechanism to generate poloidal fields out of the predominantly toroidal fields produced by stellar differential rotation. We present the first 3D general-RELATIVISTIC MAGNETohydrodynamic collapsar simulations initialized with toroidal MAGNETic field profiles that closely follows those of pre-collapse stellar models. As the toroidal field in the disk becomes dynamically important, it seeds the dynamo, producing coherent poloidal MAGNETic loops that appear at $\sim \mathcal{O}(100)$ gravitational radii and are then advected inward along paths that may deviate from the disk midplane. The resulting poloidal fields thread the BLACK HOLE (BH) and launch highly variable, wobbling RELATIVISTIC JETs on timescales of order seconds, with the onset depending on the initial MAGNETic field and the plasma circularization radius. Although the JETs are highly variable and misaligned with the BH spin axis, they sustain $\gtrsim 10^{50}$ erg s$^{-1}$, comparable to that inferred for long GAMMA-RAY BURSTs (LGRB). We identify MAGNETic-flux inversions driven by the stochastic dynamo, leading to the formation of striped JETs that could be imprinted in LGRB light curves. These results demonstrate that the accretion0disk dynamo provides a robust pathway for JET production in collapsars across a broad range of progenitors.
[abstract 3 / 36] Wow! (score: 7) - Title: The impact of flickering variability and MAGNETisation on the dynamics, stability and morphology of radio-loud AGN JETsAuthors: Emma L. Elley, James H. Matthews, Henry Whitehead, Alex J. Cooper,Comments:Subjects: astro-ph.HE astro-ph.GACreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
The physics governing the morphology of radio-loud AGN JETs is not fully understood. We investigate how MAGNETization, flickering JET power and their interplay affects the morphology of RADIO GALAXies. We present a grid of RELATIVISTIC MAGNETohydrodynamic simulations using the PLUTO code covering constant and variable JETs with two levels of MAGNETisation. We find that the constant high MAGNETisation JETs can lead to highly asymmetrical cocoon morphologies, whilst the variable high MAGNETisation JET can exhibit a broken morphology, caused by a discontinuous JET beam. Our work highlights the importance of MAGNETisation and variability on the stability and resulting morphology of radio-loud AGN JETs, suggesting both are significant factors in addition to JET power or environment. Furthermore, we show that the interaction between MAGNETisation and variability can lead to the development of localised kink instabilities along the JET beam. Finally, we discuss the effects of hydrodynamic mixing in low MAGNETisation JETs and the role of viewing angle dependence in comparisons between our simulations and observed sources. To facilitate this comparison we present a library of simulated radio images at different times in the simulations and from various viewing angles, which highlight a diverse set of complex morphologies.
[abstract 4 / 36] Yes (score: 6) - Title: On the Apparent Correlation between X-ray and Neutrino Luminosities of Active Galactic NucleiAuthors: Jian-Jun Luo, Ming-Xuan Lu, Yun-Feng Liang,Comments: 10 pages, 6 figures, 1 table. Accepted for publication in Journal of High Energy AstrophysicsSubjects: astro-ph.HECreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
Recent studies have reported a linear correlation between the hard X-ray and high-energy neutrino luminosities of ACTIVE GALACTIC NUCLEi (AGN), suggesting a possible physical connection between these two messengers. In this work, we challenge this interpretation by demonstrating that the observed correlation may arise purely from selection effects. We analyze 10 years of IceCube public data for a sample of Seyfert galaxies and BLAZARs from the \textit{SWIFT} BAT catalog. While our data reproduces the apparent $L_ν$--$L_X$ correlation for sources with mild (but not significant) neutrino evidence, we show through Monte Carlo simulations that the same correlation appears even when analyzing random sky positions with no astrophysical sources. The key issue is that TS-based source selection effectively restricts the neutrino flux to a narrow range (a factor of several), while the luminosity distance of the sample spans $\sim4$ orders of magnitude. This causes the luminosity $L = 4πD_L^2 F$ to be dominated by the distance term rather than intrinsic flux variations, creating an artificial correlation. While a robust flux correlation ($F_ν$--$F_X$) for high-significance sources may indicate a genuine physical link, our results demonstrate that a luminosity-luminosity correlation alone is insufficient to establish a physical relationship between neutrino and X-ray emission in AGN.
[abstract 5 / 36] Yes (score: 6) - Title: The Very Late Time Afterglow of GW170817 Favors a Wobbling JetAuthors: Hao Wang, Ore Gottlieb, Aman Katira, Muskan Yadav, Lei Lei, Yi-Zhong Fan, Da-Ming Wei,Comments: 8 pages, 2 figures, 1 table. Comments are welcomeSubjects: astro-ph.HECreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
GW170817 remains the only binary neutron star merger detected through multimessenger emission. Its afterglow has been monitored for nearly a decade, offering an unprecedented opportunity to probe the properties of the outflow. The shallow decay of the very late-time afterglow challenges the prediction of a collimated structured JET. Motivated by recent general-RELATIVISTIC MAGNETohydrodynamic simulations, we propose that the GW170817 afterglow is powered by a wobbling JET that drags a ring on the sky. This structure predicts a post-break decay rate shallower than that of a collimated JET, as observers will see a progressively longer emitting arc after the break. A misaligned ring-shaped JET can therefore self-consistently explain the multimessenger data without invoking any extra component. Through a Bayesian analysis of the multimessenger data, we find a ring-shaped JET is favored over a collimated JET at a significance level of 4.8$σ$. Our results imply a wobbling angle of $\sim 27^\circ$. Such a large angle points to a significant disk tilt, potentially arising from disk-infalling gas interaction or asymmetric angular momentum ejection. Similar shallow decays have also been found in other GRB afterglows, raising the possibility that wobbling JETs are common among GRBs.
[abstract 6 / 36] Yes (score: 5) - Title: TeV to PeV neutrinos from AGN coronaeAuthors: Simon Sotirov,Comments: Accepted for publication in JCAPSubjects: astro-ph.HECreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
In this paper, we attempt to explain the TeV - sub PeV neutrinos observed by IceCube assuming that their sources are ACTIVE GALACTIC NUCLEi (AGN). The results are obtained in the model where the thermal accretion disc emits in the UV-optical range inside the hot electron plasma cloud. We focus on the analytical solution for the COMPTONization problem obtained from consideration at the microscopic level and try to avoid fitting the coronal spectrum from spectral observations. Using the Monte-Carlo approach to model photopion interactions in the central regions of AGN and then after taking into account the cosmological evolution it is shown that within the framework of this approach it is possible to describe both $\sim$ 100 TeV and sub PeV neutrinos from AGN taking into account only photohadronic interactions.
[abstract 7 / 36] Yes (score: 5) - Title: Solving the cooling flow problem with combined JET-wind AGN feedbackAuthors: Aoyun He, Feng Yuan, Suoqing Ji, Minhang Guo, Yuan Li, Haiguang Xu, Ming Sun, Haojie Xia, Yuanyuan Zhao,Comments: 27 pages, 7 figures. Accepted for publication in Science AdvancesSubjects: astro-ph.GACreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
Active galactic nucleus (AGN) feedback is widely viewed as the most promising solution to the long-standing cooling flow problem in galaxy clusters, yet previous models prescribe JET properties inconsistent with accretion physics. We perform an idealized hydrodynamic simulation of a galaxy cluster with no merger history and a relaxed state, with its other properties similar to the Perseus cluster using the MACER framework, incorporating both JETs and winds whose properties are constrained by general RELATIVISTIC MAGNETohydrodynamic simulations of BLACK HOLE accretion and observations. The combined feedback reproduces key observables, including cold gas mass, STAR FORMATION rate, thermodynamic radial profiles, and BLACK HOLE growth, while JET-only or wind-only models fail. The success arises from turbulence driven by JET-wind shear that enhances kinetic-to-thermal energy conversion, boosting heating efficiency by factors of three and six relative to wind-only and JET-only cases, respectively.
[abstract 8 / 36] Yes (score: 5) - Title: Spectral Appearance of Self-gravitating Disks Powered by Stellar Objects: Universal Effective Temperature in the Optical Continuum and Application to Little Red DotsAuthors: Yi-Xian Chen, Hanpu Liu, Ruancun Li, Bingjie Wang, Yilun Ma, Yan-Fei Jiang, Jenny E. Greene, Eliot Quataert, Jeremy Goodman,Comments: Accepted to ApJLSubjects: astro-ph.HE astro-ph.GA astro-ph.SRCreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
We revisit the spectral appearance of extended self-gravitating accretion disks surrounding compact central objects such as supermassive BLACK HOLEs. Using dust-poor opacities, we show that all optically thick disk solutions possess a universal outer effective temperature of $T_{\rm eff}\sim 4000-4500$K, closely resembling compact, high-redshift sources known as Little Red Dots (LRDs). Assuming the extended disk is primarily heated by stellar sources, this ``disk Hayashi limit" fixes the dominant optical continuum temperature of the disk spectrum independent of accretion rate $\dot{M}$, central mass $M_\bullet$, and disk viscosity $α$, and removes the parameter-tuning required in previous disk interpretations of LRDs. The formation and accretion of embedded stellar objects can both power the emission of the outer disk and hollow out the inner disk, suppressing variable UV/X-ray associated with a standard QUASAR. The resulting disk emission is dominated by a luminous optical continuum while a separate, non-variable UV component arises from stellar populations on the nuclear to galaxy scale. We map the optimal region of parameter space for such systems and show that LRD-like appearances naturally emerge for $\dot{M}/α\gtrsim 0.1 M_\odot /{\rm yr}$, a threshold insensitive to $M_\bullet$, below which the system may transition into classical non-self-gravitating AGN disks, potentially a later evolution stage. We expect this transition to be accompanied by the enhancement of metallicity and production of dust, giving rise to far infrared emission. This picture offers a physically motivated and quantitative framework connecting LRDs with AGNs and their associated nuclear stellar population.
[abstract 9 / 36] Yes (score: 5) - Title: Magnetar-powered long GAMMA-RAY BURSTs and connection to superluminous SUPERNOVAe and fast radio burstsAuthors: Yu-Qi Zhou, Shuang-Xi Yi, Yu-Peng Yang, Yan-Kun Qu, Ning Gai, Yan-Ke Tang, Fa-Yin Wang,Comments: Accepted for publication in ApJL; 28 pages, 5 figures and 2 tablesSubjects: astro-ph.HECreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
Based on X-ray afterglow observations from the SWIFT satellite, we construct a sample of 169 long GAMMA-RAY BURSTs (LGRBs) exhibiting the canonical MAGNETar plateau signature, i.e., a plateau followed by a $t^{-2}$ decay. We derive the plateau luminosity $L_0$ and break time $t_b$ for each burst by performing Markov Chain Monte Carlo (MCMC) fits to the light curves, and estimate pseudo-redshifts for bursts lacking known redshifts via the Amati relation. The fundamental MAGNETar parameters are subsequently inferred: the surface polar MAGNETic field strength $B_p \in [0.39,\ 23.08] \times 10^{15}$G and the initial spin period $P_0 \in [0.95,\ 13.79]$ms. Statistical analysis shows that both the known-redshift subsample and the full sample follow the Dainotti correlation between $L_0$ and $t_b$ with a slope close to $-1$, supporting a constant energy injection rate during the plateau phase. Furthermore, we identify a significant correlation between $B_p$ and $P_0$: $B_p \propto P_0^{0.83 \pm 0.09}$ for the full sample and $B_p \propto P_0^{0.80 \pm 0.16}$ for the known-redshift subsample, with both slopes consistent within uncertainties. Compared to MAGNETars powering superluminous SUPERNOVAe (SLSNe) and fast radio bursts (FRBs), GRB MAGNETars possess systematically stronger MAGNETic fields (by approximately one order of magnitude), suggesting fundamental differences in their progenitor systems or collapse conditions. This study provides a physics-motivated, model-consistent sample of MAGNETar-candidate GRBs, offering a robust foundation for statistical investigations within the MAGNETar central engine model and placing new observational constraints on the birth properties of these extreme compact objects.
[abstract 10 / 36] Yes (score: 5) - Title: Guitar Nebula: extreme accelerator in extreme environmentAuthors: Igor Nikolaevich Nikonorov, Maxim Vladimirovich Barkov, Maxim Lyutikov,Comments: 7+11 pages, 3+3 figures, 4 tables. Submitted to JHEAPSubjects: astro-ph.HECreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
Guitar nebula is a prime example of a class of bow-shock pulsar wind nebulae (PWNe), powered by a wind of a supersonically moving neutron star. Bow-shock PWNe can probe particle acceleration processes in RELATIVISTIC pulsar winds, as well as the structure of the interstellar medium (ISM). We demonstrate that the Guitar is an exceptional object in a number of ways. First, particles escaping the PWN and forming the X-ray ``kinetic JET'' need to be accelerated to the energies corresponding to the maximal electric potential of the neutron star $η_\text{acc}\gtrsim 3/4$ : it is another example of the class of extreme accelerators. Second, exceptionally bright H$_α$ emission requires that the central pulsar PSR J2225+6535 passes through a dense, low ionization ISM region. Bright X-ray emission of the ``kinetic JET'' then also requires exceptionally high MAGNETic field, $\sim 100~μ$G. We hypothesize that Guitar passes through the one of long-predicted, narrow dense shells of an old SUPERNOVA remnant, currently in the ``pressure-driven snowplow'' regime.
[abstract 11 / 36] Yes (score: 4) - Title: No Measurable Changes in Radio and X-ray Emission Surrounding Glitches in the Young Pulsar PSR J2229+6114Authors: 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: 12 pages, 5 figures. Submitted to ApJ, comments welcomeSubjects: astro-ph.HECreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
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 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 NICER. Our data show no measurable changes 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 12 / 36] Yes (score: 4) - Title: Revisiting the 2021 Outburst of the BHC MAXI J1803-298 Using NICER, NUSTAR, and Insight-HXMT DataAuthors: Kaushik Chatterjee, Sujoy K. Nath,Comments: 12 pages, 9 figures, 5 tables (Accepted for Publication in the Journal for High Energy Astrophysics)Subjects: astro-ph.HECreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
We present a broadband spectral and timing study of the BLACK HOLE candidate MAXI J1803-298 during its 2021 outburst using simultaneous observations from NICER, NUSTAR, and Insight-HXMT. The combined multi-instrument coverage allows us to investigate the evolution of low-frequency quasi-periodic oscillations (LFQPOs) together with the spectral properties of the source over a wide energy range. During the early observation epoch, the source exhibits a hard or hard-intermediate spectral state dominated by Comptonized emission with reflection features. Spectral modeling within the framework of the two-component advective flow (TCAF) model indicates the presence of a sub-Keplerian halo and a Keplerian disk with a shock located at 130 Schwarzschild radii, and provides an independent estimate of the BLACK HOLE mass. A prominent LFQPO is detected during this epoch with a centroid frequency evolving from 0.35 Hz to 0.5 Hz and extending up to 100 keV. The energy-dependent fractional rms variability suggests that the modulation originates primarily from the Comptonizing inner accretion flow. In contrast, a later observation epoch shows a softer spectral state characterized by stronger disk emission and a steeper photon index, during which no LFQPO is detected. We also demonstrate that cospectral analysis effectively mitigates dead-time-induced distortions in NUSTAR timing studies, confirming the intrinsic nature of the detected variability. The combined spectral and timing results support a scenario in which LFQPOs in MAXI J1803-298 arise from the dynamically evolving inner accretion flow.
[abstract 13 / 36] Yes (score: 4) - Title: Tidal disruption of a low-mass star in an ACTIVE GALACTIC NUCLEus as the origin of the PS16dtm outburstAuthors: Marzena Śniegowska, Bożena Czerny, Michal Zajaček, Valentina Rosa, Vladimír Karas, Taj Jankovič, Tanja Petrushevska, Dragana Ilić, Benny Trakhtenbrot, Petr Kurfürst,Comments: 17 pages, 10 figures, submitted to A&A. Comments welcomeSubjects: astro-ph.HECreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
The event PS16dtm, which occured in the center of the Narrow Line Seyfert 1 (NLS1) galaxy SDSS J015804.75-005221.8 (z = 0.080440), is one of the few candidates for a tidal disruption event in an already-acretting ACTIVE GALACTIC NUCLEus (AGN). We aim to shed light on the character of the tidal disruption event in this source since it exhibits unusual peculiarities, such as the double-peak optical/UV light curve and a low blackbody temperature with a lack of X-ray emission. We perform spectral analysis of the source before and during the event. We model the time evolution of the luminosity profile using a numerical code that describes the viscous evolution of the flow. From the combined spectral and timing studies, we interpret the event as the disruption of a $\sim 0.3 M_{\odot}$ main-sequence star, or gradual partial disruption of the low-mass giant star. The star is likely on a circular orbit, embedded in the accretion disc. The discussion of the evolution of the star rather suggests that the orbit is counter-rotating. We observe the system at a sufficiently large viewing angle that the actual disruption process is not directly observed. The disrupted star and inner disc are shielded from the observer by a gaseous envelope. Further observations of the system returning to the previous NLS1 state, particularly in the X-ray band, are needed to confirm the proposed scenario and to put constraints on the return to a regular NLS1 state.
[abstract 14 / 36] (score: 3) - Title: Measurement of transverse POLARIZATION of $Λ$ and $\barΛ$ hyperons inside JETs in $pp$ collisions at $\sqrt{s}=200$ GeVAuthors: STAR Collaboration, B. E. Aboona, J. Adam, G. Agakishiev, I. Aggarwal, M. M. Aggarwal, Z. Ahammed, A. Aitbayev, I. Alekseev, E. Alpatov, A. K. Alshammri, A. Aparin, S. Aslam, J. Atchison, G. S. Averichev, V. Bairathi, X. Bao, P. Barik, K. Barish, S. Behera, P. Bhaga t, A. Bhasin, S. Bhatta, I. G. Bordyuzhin, J. D. Brandenburg, A. V. Brandin, C. Broodo, X. Z. Cai, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, J. Ceska, I. Chakaberia, Y. S. Chang, Z. Chang, A. Chatterjee, D. Chen, J. H. Chen, L. Chen, Q. Chen, W. Chen, Z. Chen, J. Cheng, Y. Cheng, W. Christie, X. Chu, S. Corey, H. J. Crawford, G. Dale-Gau, A. Das, D. De Souza Lemos, T. G. Dedovich, I. M. Deppner, A. A. Derevschikov, A. Deshpande, A. Dhamija, A. Dimri, P. Dixit, X. Dong, J. L. Drachenberg, E. Duckworth, J. C. Dunlop, Y. S. El-Feky, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, O. Eyser, B. Fan, Y. Fang, R. Fatemi, S. Fazio, H. Feng, Y. Feng, E. Finch, Y. Fisyak, F. A. Flor, B. Fu, C. Fu, T. Fu, T. Gao, Y. Gao, G. Garcia, F. Geurts, A. Gibson, A. Giri, K. Gopal, M. Gor don, X. Gou, D. Grosnick, A. Gu, J. Gu, A. Gupta, A. Hamed, R. J. Hamilton, J. Han, X. Han, M. D. Harasty, J. W. Harris, H. Harrison-Smith, L. B. Havener, X. H. He, Y. He, C. Hu, Q. Hu, Y. Hu, H. Huang, H. Z. Huang, S. L. Huang, T. Huang, Y. Huang, Y. Huang, Y. Huan g, M. Isshiki, W. W. Jacobs, A. Jalotra, C. Jena, Y. Ji, J. Jia, X. Jiang, C. Jin, Y. Jin, N. Jindal, X. Ju, E. G. Judd, S. Kabana, D. Kalinkin, J. Kang, K. Kang, A. R. Kanuganti, D. Kapukchyan, K. Kauder, D. Keane, A. Kechechyan, M. Kesler, A. Khanal, A. Khanal, J. Kim, A. Kiselev, A. G. Knospe, L. Kochenda, Y. Kong, A. A. Korobitsin, B. Korodi, A. Yu. Kraeva, P. Kravtsov, L. Kumar, M. C. Labonte, R. Lacey, J. M. Landgraf, C. Larson, A. Lebedev, R. Lednicky, J. H. Lee, Y. H. Leung, C. Li, D. Li, H-S. Li, H. Li, H. Li, H. Li, W. Li, X. Li, X. Li, Y. Li, Z. Li, Z. Li, X. Liang, T. Lin, Y. Lin, C. Liu, G. Liu, H. Liu, L. Liu, L. Liu, Z. Liu, Z. Liu, T. Ljubicic, O. Lomicky, E. M. Loyd, T. Lu, J. Luo, X. F. Luo, V. B. Luong, L. Ma, R. Ma, Y. G. Ma, N. Magdy, B. Maghoul, R. Manikandhan, O. M atonoha, K. Menduli, K. Mi, N. G. Minaev, B. Mohanty, B. Mondal, M. M. Mondal, I. Mooney, D. A. Morozov, M. I. Nagy, C. J. Naim, A. S. Nain, J. D. Nam, M. Nasim, H. Nasrulloh, E. Nedorezov, J. M. Nelson, M. Nie, G. Nigmatkulov, T. Niida, L. V. Nogach, T. Nonaka, G. Odyniec, A. Ogawa, S. Oh, V. A. Okorokov, K. Okubo, B. S. Page, M. Pal, S. Pal, A. Pandav, A. Panday, A. K. Pandey, Y. Panebratsev, T. Pani, P. Parfenov, A. Paul, S. Paul, C. Perkins, S. Ping, I. D. Ponce Pinto, M. Posik, E. Pottebaum, A. Povarov, S. Prodhan, T. L. Protzman, N. K. Pruthi, J. Putschke, Y. Qi, Z. Qin, H. Qiu, S. K. Radhakrishnan, A. Rana, R. L. Ray, C. W. Robertson, O. V. Rogachevsky, M. A. Rosales Aguilar, D. Roy, L. Ruan, A. K. Sahoo, N. R. Sahoo, H. Sako, S. Salur, S. S. Sambyal, E. Samigullin, D. T. Samuel, J. K. Sandhu, S. Sato, B. C. Schaefer, N. Schmitz, J. Seger, R. Seto, P. Seyboth, N. Shah, E. Shahaliev, P. V. Shanmuganathan, T. Shao, M. Sharma, N. Sharma, R. Sharma, S. R. Sharma, A. I. Sheikh, D. Shen, D. Y. Shen, K. Shen, S. Shi, Y. Shi, Shilpa, E. Shulga, F. S, J. Singh, S. Singha, P. Sinha, M. J. Skoby, Y. Söhngen, Y. Song, T. D. S. Stanislaus, M. Strikhanov, Y. Su, X. Sun, Y. Sun, B. Surrow, D. N. Svirida, Z. W. Sweger, A. C. Tamis, A. H. Tang, Z. Tang, A. Taranenko, T. Tarnowsky, J. H. Thomas, A. Timofeev, D. Tl usty, M. V. Tokarev, D. Torres-Valladares, S. Trentalange, O. D. Tsai, C. Y. Tsang, Z. Tu, J. E. Tyler, T. Ullrich, D. G. Underwood, G. Van Buren, A. N. Vasiliev, F. Videbæk, S. Vokal, S. A. Voloshin, F. Wang, G. Wang, G. Wang, J. S. Wang, J. Wang, K. Wang, X. W ang, Y. Wang, Y. Wang, Y. Wang, Z. Wang, Z. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, G. D. Westfall, H. Wieman, G. Wilks, S. W. Wissink, C. P. Wong, J. Wu, X. Wu, X. Wu, X. Wu, B. Xi, Y. Xiao, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, X. Xu, Y. Xu, Y. Xu, Y. Xu, Y. Xu, Z. Xu, Z. Xu, G. Yan, Z. Yan, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Ye, Z. Ye, L. Yi, Y. Yu, W. Yuan, W. Zha, C. Zhang, D. Zhang, J. Zhang, K. Zhang, L. Zhang, S. Zhang, W. Zhang, W. Zhang, X. Zhang, Y. Zhang, Y. Zhang, Y. Zhang, Y. Zhang, Z. Zhan g, Z. Zhang, F. Zhao, J. Zhao, S. Zhou, Y. Zhou, C. Zhu, X. Zhu, M. Zurek, M. Zyzak,Comments:Subjects: hep-exCreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
A surprisingly large transverse POLARIZATION of $Λ$ hyperons in unpolarized hadron-nucleon/nucleus collisions has been observed for 50 years, and the origin of this POLARIZATION remains an important open question. Recently, theoretical frameworks have advanced in describing this puzzle with the polarizing fragmentation function (PFF). We report the first measurement of $Λ$ and $\overlineΛ$ transverse POLARIZATION inside JETs in unpolarized proton-proton collisions, which is directly attributed to the PFF. The POLARIZATION is measured as a function of the JET transverse momentum, the fraction of the JET momentum carried by $Λ$($\overlineΛ$) hyperons, and the transverse momentum of $Λ(\overlineΛ)$ hyperons relative to the JET axis. Covering a wide JET-energy range, these data provide the first constraints on the gluon PFF and allow tests of TMD evolution and its universality.
[abstract 15 / 36] (score: 3) - Title: Observation of a cross-section enhancement near the $t\bar{t}$ production threshold in $\sqrt{s}=13$ TeV $pp$ collisions with the ATLAS detectorAuthors: ATLAS Collaboration,Comments: 64 pages in total, author list starting page 47, 12 figures, 4 tables, published on Reports on Progress in Physics. All figures including auxiliary figures are available at[abstract 16 / 36] (score: 3)Subjects: hep-exCreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14
A measurement of $t\bar{t}$ production is presented in the invariant-mass region near the pair production threshold, $m_{t\bar{t}} \sim 345$ GeV, in final states with two charged leptons and multiple JETs. The measurement is based on $140\,\mathrm{fb}^{-1}$ of proton-proton collision data collected at $\sqrt{s} = 13$ TeV with the ATLAS detector at the Large Hadron Collider. The data are compared to two models of $t\bar{t}$ production: a baseline model including only perturbative QCD predictions for the hard process, and an extended model that, in addition, incorporates non-RELATIVISTIC QCD simulations of colour-singlet quasi-bound-state formation near the $t\bar{t}$ threshold. The agreement between the data and the models is quantified via a profile-likelihood fit to the reconstructed $m_{t\bar{t}}$ distributions, in bins of two angular observables sensitive to spin-correlations in the $t\bar{t}$ system. An excess of events is observed over the baseline perturbative QCD prediction, with an observed significance over $8$ standard deviations. This excess is consistent with the formation of colour-singlet and spin-singlet $S$-wave quasi-bound $t\bar{t}$ states, as predicted by non-RELATIVISTIC QCD, and corresponds to an observed cross-section of $9.3^{+1.4}_{-1.3}$ pb.
arXiv:2605.02136 [pdf, ps, other]Black-hole shadows are purely geometric in the leading-order geometric-optics approximation: their boundary is set by null geodesics and carries no information about the POLARIZATION of the probing radiation. At subleading order, the gravitational spin Hall effect of light introduces helicity-dependent corrections to photon propagation. We show that, in any static spherically symmetric spacetime, an exact equatorial reflection symmetry of the full spin Hall equations forces these corrections to cancel at the capture threshold: the critical impact parameter remains identical for opposite helicities, and no POLARIZATION-dependent shadow splitting occurs. Rotation breaks this symmetry. Using a double perturbative expansion in the black-hole spin $χ= a/M$ and in the inverse frequency $1/ω$, we derive the first non-vanishing helicity-dependent shift of the critical impact parameter for slowly rotating (Kerr) BLACK HOLEs. The effect is linear in $χ$, scales as $1/ω$, and appears as a $\cosϕ$ modulation of the shadow boundary, with a sign reversal on one side of the image for spins $χ\gtrsim 0.21$. Although parametrically small for astrophysical sources, the splitting is a robust, model-independent signature of spin-optical dynamics in strong fields. Our analysis also identifies a methodological pitfall: a naive radial projection that suppresses transverse motion can produce a spurious splitting even in spherical symmetry, a lesson of general relevance for future studies of spin-optical effects.
arXiv:2605.11734 [pdf, ps, other]We introduce a new general-RELATIVISTIC timing observable that measures the breaking of reflection symmetry in photon arrival times caused by BLACK HOLE spin. Using backward ray tracing in the Kerr spacetime, we construct time-delay maps across the observer image plane and define a mirror-paired asymmetry based on photons arriving from opposite sides of the projected spin axis. In the Schwarzschild limit ($a=0$), the asymmetry vanishes to numerical precision, providing a stringent validation test of the method. For rotating BLACK HOLEs, Kerr rotation breaks the left-right propagation symmetry of null geodesics, producing systematic differences between prograde and retrograde photon trajectories and resulting in a nonzero mirror-paired timing asymmetry, $A_t$. We find that $A_t$ increases with spin and depends strongly on observer inclination and emission radius, with the largest signals arising from emission close to the BLACK HOLE and from intermediate to high inclinations. Converting the dimensionless asymmetry into physical units yields timing offsets ranging from seconds to hours for representative supermassive BLACK HOLE systems. Unlike traditional timing analyses based on spatially integrated signals, the observable introduced here isolates directional information encoded in Kerr photon propagation and provides a physically motivated timing signature of BLACK HOLE rotation. We discuss the implications of this effect for strong-gravity timing studies and X-ray reverberation mapping.
arXiv:2605.12598 [pdf, ps, other]We present measurements of the depth of shower maximum, Xmax, for cosmic-ray-induced extensive air showers recorded by the fluorescence detector of the Pierre Auger Observatory over 17 years. The data set covers primary energies from 10^17.7 eV to beyond 10^19.6 eV. With improved event reconstruction and an exposure 2.4 times larger than in our previous analysis, this work confirms and refines our conclusions on the mass composition at ultra-high energies. The energy evolution of the mean Xmax exhibits a pronounced break at around 10^18.4 eV, providing direct, model-independent evidence for a change in the evolution of the mass composition. Independently, the observed decrease of the Xmax fluctuations with energy indicates a transition toward a heavier and less diverse primary mass composition. No statistically significant declination dependence of the Xmax distributions is observed within the exposure of the Observatory, indicating an isotropic mass composition. The mean and standard deviation of the Xmax distributions, interpreted with air-shower simulations, yield the energy dependence of the average and variance of the logarithmic mass of COSMIC RAYs arriving at Earth. Furthermore, energy-dependent fractional abundances of four representative primary-mass groups (p, He, CNO, Fe) are obtained by fitting the observed Xmax distributions in each energy bin with a weighted sum of elemental templates. These results provide strong evidence against a long-standing assumption that ultra-high-energy COSMIC RAYs are predominantly protons: above ~10^18.4 eV, the average cosmic-ray mass increases, accompanied by a steadily decreasing diversity in the elemental composition.
arXiv:2605.13514 [pdf, ps, other]Wide-separation lensed QUASARs (WSLQs) are rare systems that arise from the chance alignment of two objects: a galaxy cluster and a background QUASAR. After two decades, only seven WSLQs have been found. Here, we report the discovery of COOLJ1153+0755 by the COOL-LAMPS collaboration in DECaLS imaging and its confirmation with follow-up observations with the Magellan Telescopes and the Nordic Optical Telescope. This system features two multiply-imaged QUASARs each lensed into four images by the same $z=0.4301$ cluster: a classic broad-line Type I QUASAR at $z=1.524$ (COOLJ1153A) and a dust-obscured Type II QUASAR at $z=1.939$ (COOLJ1153B), with maximum image separations of $25.''6$ and $26.''0$, respectively. We construct a lens model to estimate a projected cluster mass of $M(<500\,{\rm kpc})\sim3.3\times10^{14}{\rm M}_{\odot}$ and relative time delays between the three brightest images of each QUASAR of $Δt_{\rm \,A3,A1}\sim800$, $Δt_{\rm \,A2,A1}\sim1200$, $Δt_{\rm \,B1,B3}\sim800$, and $Δt_{\rm \,B2,B3}\sim1000$ days. COOLJ1153A resides in a dense environment with three nearby galaxies, two of which are also strongly lensed. We identify COOLJ1153+0755 without making a morphological cut in the DECaLS catalog; none of its multiple images are classified as point sources in those data, implying that morphology-based selection would miss such systems. COOLJ1153+0755 expands the WSLQ sample from 7 to 8 systems (9 individual QUASARs), adding two powerful laboratories for probing BLACK HOLE-galaxy co-evolution at Cosmic Noon and for time-delay cosmography constraints on the Hubble constant, $H_0$.
arXiv:2406.03568 [pdf, ps, other]On May 29, 2023, the LIGO Livingston observatory detected the gravitational-wave signal GW230529_181500 from the merger of a neutron star with a lower mass-gap compact object. Its long inspiral signal provides a unique opportunity to test general relativity (GR) in a parameter space previously unexplored by strong-field tests. In this work, we performed parameterized inspiral tests of GR with GW230529_181500. Specifically, we search for deviations in the frequency-domain GW phase by allowing for agnostic corrections to the post-Newtonian coefficients. We performed tests with the Flexible Theory Independent and Test Infrastructure For General Relativity frameworks using several quasicircular waveform models that capture different physical effects (higher modes, spins, tides). We find that the signal is consistent with GR for all deviation parameters. Assuming the primary object is a BLACK HOLE, we obtain particularly tight constraints on the dipole radiation at $-1$PN order of $|δ\hatφ_{-2}| \lesssim 8 \times 10^{-5}$, which is a factor $\sim17$ times more stringent than previous bounds from the neutron star--BLACK HOLE merger GW200115_042309, as well as on the 0.5PN and 1PN deviation parameters. We discuss some challenges that arise when analyzing this signal, namely biases due to correlations with tidal effects and the degeneracy between the 0PN deviation parameter and the chirp mass. To illustrate the importance of GW230529_181500 for tests of GR, we mapped the agnostic $-1$PN results to a class of Einstein-scalar-Gauss-Bonnet (ESGB) theories of gravity. We also conducted an analysis probing the specific phase deviation expected in ESGB theory and obtain an upper bound on the Gauss-Bonnet coupling of $\ell_{\rm GB} \lesssim 0.51~\rm{M}_\odot$ ($\sqrt{α_{\rm GB}} \lesssim 0.28$ km), which is better than any previously reported constraint.
arXiv:2510.05400 [pdf, ps, other]Binary neutron star mergers are unique probes of matter at extreme density and standard candles of cosmic expansion. The only such event observed in both gravitational waves and electroMAGNETic radiation, GW170817, revealed the origin of heavy elements, constrained the neutron star equation of state, and provided an independent measurement of the Hubble constant. Current detectors such as LIGO, Virgo, and KAGRA capture only the final minutes of inspiral, offering limited advance warning and coarse sky localization. In this study, we present a comprehensive analysis of binary neutron star signals for lunar-based gravitational-wave observatories (LILA, LGWA, GLOC) envisioned within NASA's Artemis and Commercial Lunar Payload Services programs, and compare their performance with current and next-generation Earth-based facilities. For GW170817-like sources, we find that lunar detectors can forecast mergers weeks to months in advance and localize them to areas as small as 0.01 deg$^{2}$, far beyond the reach of terrestrial detectors. We further show that lunar observatories would detect on the order of 100 well-localized mergers annually, enabling coordinated multi-messenger follow-up. When combined in a multi-band LIGO+Moon network, sky-localization areas shrink to just a few arcsec$^{2}$, comparable to the field of view of the James Webb Space Telescope at high zoom. Multi-band parameter estimation also delivers dramatic gains: neutron star mass-ratio uncertainties can be measured with $\sim0.1\%$ precision, spin constraints to 0.001$\%$ with luminosity distance errors to 1$\%$ level, enabling precision measurements of the equation of state and the cosmic expansion rate. Our results demonstrate that lunar gravitational-wave observatories would revolutionize multi-messenger astrophysics with binary neutron stars and open a unique discovery landscape in the Artemis era.
arXiv:2511.02362 [pdf, ps, other]We present the application of the data-driven branch of the MURaM code, which follows the evolution of the active region 11640 over 4 days starting from 2012 December 30 at 12:00 UT and reproduces many key coronal extreme-ultraviolet (EUV) emission features seen in remote sensing observations. Radiative MAGNETohydrodynamic (MHD) simulations that account for sophisticated energy transport processes, such as those in the real corona, have been extended with the ability to use observations as time-dependent boundaries such that the models follow the evolution of actual active regions. This opens the possibility of a one-to-one model of a target region over an extensive time period. We use a hybrid strategy that combines fast-evolving idealized zero-$β$ models that capture the evolution of the large-scale active region MAGNETic field over a long time period and sophisticated radiative MHD models for a shorter time period of interest. The synthesized EUV images illustrate the formation of coronal loops that connect the two sunspots or fan out to the domain boundary. The model reveals in three-dimensional space fine structure in the coronal heating and plasma properties, which are usually concealed behind the EUV observables. The volumetric heating rate in bright coronal loops is proportional to $\mathbf{B}^{2}$. The emission-measure-weighted line-of-sight velocity, which represents the Doppler shift of a spectral line forming in a certain temperature range, reveals vigorous dynamics in plasma at different temperatures and ubiquitous MHD waves, as expected in the real solar corona.
arXiv:2603.08792 [pdf, ps, other]We predict the gamma-ray line emission from $r$-process nuclei synthesized in the ejecta of the accretion-induced collapse (AIC) of a MAGNETized, rapidly rotating white dwarf. Using ejecta from a two-dimensional general-RELATIVISTIC neutrino-MAGNETohydrodynamic simulation, further evolved with a radiation-hydrodynamics code coupled to an in-situ nuclear reaction network, we construct angle-dependent gamma-ray spectra in the $0.01$-$10\,\mathrm{MeV}$ band via composition-dependent ray-tracing through the ejecta. The emission between $\sim$1 and $10\,$d is dominated by $^{132}$I ($t_{1/2} = 2.3\,$h), continuously replenished by the decay of its parent $^{132}$Te ($t_{1/2} = 3.2\,$d), with additional contributions from $^{131}$I, $^{133}$Xe, and $^{132}$Te. At $t\gtrsim 20$ d, $^{56}$Co (from $^{56}$Ni decay) becomes the primary emitter. The simultaneous presence of $r$-process and iron-peak gamma-ray lines is distinctive of AIC ejecta and absent in binary neutron star mergers, where iron-peak nuclei are generally not synthesized. Comparing with the $3σ$ continuum sensitivities of planned MeV gamma-ray telescopes (COSI, AMEGO-X, e-ASTROGAM, GRAMS, GammaTPC), we find the brightest $r$-process lines detectable to $\sim 10\,\mathrm{Mpc}$ by GammaTPC and GRAMS, with the signal approaching their sensitivity threshold at $30\,\mathrm{Mpc}$. The $r$-process spectral features survive time integration over $\sim 30$ d exposures, demonstrating robustness against the long observation times required by gamma-ray detectors.
arXiv:2605.05875 [pdf, ps, other]Cephalopod pulsed-JET locomotion is not a single isolated expulsion event, but a coordinated cycle involving JET expulsion, passive gliding, and mantle refilling. Inspired by this cycle-resolved biological strategy, this paper presents a cephalopod-inspired pulsed-JET robot with a rigid-soft hybrid origami mantle that enables large, actively driven, and geometry-guided body deformation. The proposed mantle integrates rigid folding panels with a compliant silicone framework, allowing a 75% effective cavity-volume reduction during expulsion and reducing the projected cross-sectional drag area by approximately 75.7% in the contracted gliding configuration. Using this platform, we formulate a cycle-resolved framework to separately investigate how expelled volume, glide duration, and refill pathway influence whole-cycle locomotion performance. Experiments show that the robot reaches a peak speed of approximately 0.5 m/s (3.8 BL/s) and an average speed exceeding 0.2 m/s (1.5 BL/s) within the first JETting cycle. The results further demonstrate the roles of high expelled-volume-ratio contraction in speed generation, reduced-drag-area gliding under different glide durations, and mantle-aperture-inspired passive inlet valves in assisting refill. This work provides both a robotic implementation of actively deformable cephalopod-like JET propulsion and a unified experimental platform for studying expulsion-gliding-refilling dynamics in pulsed-JET locomotion.
arXiv:2605.11083 [pdf, ps, other]The cross-correlation between tracers of large-scale structure, such as galaxies or QUASARs, and the thermal Sunyaev-Zel'dovich (tSZ) signal yields a measure of the bias-weighted mean electron pressure, $\langle b_\mathrm{h} P_\mathrm{e} \rangle$, where $b_\mathrm{h}$ is the halo bias and $P_\mathrm{e}$ is the electron pressure. With a model for the bias, one can derive the thermal history, $\mathrm{d}y/\mathrm{d}z$, where $y$ is the Compton parameter and $z$ is redshift. We explore how these quantities depend on redshift, cosmology, and the physics of galaxy formation using the FLAMINGO suite of cosmological hydrodynamical simulations, which spans a range of cosmological parameters and baryonic feedback implementations in volumes of up to $(2.8\,\text{Gpc})^3$. We find that $\langle b_\mathrm{h} P_\mathrm{e} \rangle$ depends steeply on $S_8 \equiv σ_8\sqrt{Ω_\mathrm{m}/0.3}$, with an effective scaling $\langle b_\mathrm{h} P_\mathrm{e} \rangle \propto S_8^{ε(z)}$, where the exponent $ε(z) \approx 3$ over the redshift range $0.1 \leq z \leq 1$. Compared with existing cross-correlation measurements using tracer samples from SDSS, BOSS, eBOSS, DES, and DESI cross-correlated with tSZ measurements from Planck, we find that models with a low-$S_8$ cosmology and strong feedback are preferred, with a joint fit yielding $S_8 = 0.72^{+0.03}_{-0.03}$ and a normalised group-mass halo baryon fraction $f_b(10^{13}\,M_\odot, z=0.1)/(Ω_b/Ω_m) = 0.10^{+0.09}_{-0.05}$ . Contrary to most probes of feedback which sample smaller scales (e.g., X-ray measurements), we show that feedback boosts $\langle b_\mathrm{h} P_\mathrm{e} \rangle$, thus providing a novel test of feedback models. Overall, our results show the thermal history provides a route to jointly constrain cosmological parameters and test models of galaxy formation.
arXiv:2605.12599 [pdf, ps, other]Galaxy mergers are fundamental drivers of galaxy evolution and BLACK HOLE (BH) growth across cosmic time. We use the Horizon-AGN simulation to investigate the fraction of galaxy pairs, the merger fraction, and the galaxy merger rate over a wide range of stellar masses and redshifts. To identify physically connected pairs, we adapt the Matthews Correlation coefficient (MCC) framework, optimizing thresholds in projected distance and redshift difference, and compare our selection to commonly used criteria in the literature. We then connect the derived galaxy merger rates to supermassive BH mergers, tracking the evolution from galaxy interactions to BH coalescences, thereby reconstructing the full merger history. We find that the galaxy pair fraction, merger fraction, characteristic timescale, and merger rate all evolve strongly with both stellar mass and redshift, with higher-mass galaxies and earlier galaxies showing elevated merger activity. BHs exhibit a similar evolutionary trend, with the volume-averaged BH merger rate peaking around cosmic noon ($z\sim2\mbox{--}3$). Our results demonstrate a close correspondence between galaxy and BH cosmic histories. This work provides a comprehensive, simulation-based framework for linking galaxy and BH merger populations, and offers refined selection criteria for future observational studies, for forecasts of gravitational wave detections with LISA, and interpretation of Pulsar Timing Array results.
arXiv:2605.12659 [pdf, ps, other]The spatiotemporal content of a black-hole movie is set jointly by source variability and by the distribution of light-travel times across the image. In the slow-light prescription, an image evaluated at fixed observer time contains photons emitted at different source times, whereas in fast light all rays sample a single source emission time. In this work we compare these light-propagation prescriptions through the lensing-band structure of Kerr geodesic delays in a controlled semi-analytic setting. For a given emitting geometry, black-hole spin, and observer inclination, we show how the coordinate-time delay distributions of Kerr null geodesics, decomposed by image order across lensing bands, can be compared with the source correlation time to quantify differences between light-propagation prescriptions. We find that when the intrinsic variability timescale is comparable to, or shorter than, the relevant delay spread, the high-inclination mismatch between fast- and slow-light curves can reach several tens of percent. Motivated by this geometric structure, we introduce brisk light, an intermediate prescription that compresses each lensing-band delay map to its dominant temporal interval rather than collapsing the full image to a single source time. The proposed methodology provides both a practical criterion for when slow light matters and an efficient route to black-hole movies that retain the leading temporal imprint of strong lensing, a regime of direct relevance for future space-based VLBI targeting photon-ring observables.
arXiv:2605.12818 [pdf, ps, other]The gravitational wave signal from merging compact binaries encodes information about their orbital and intrinsic properties. Over the last few years, state-of-the-art waveform models have begun to incorporate the effects of orbital eccentricity into their estimated signal. Over a similar period, many groups have applied these waveforms to characterize whether the imprint of eccentricity is present and, if so, measure this time-evolving property (at a suitably-defined reference point). In this work, we present a comprehensive analysis of 162 confident sources identified in the O3 and O4a observing runs of the International Gravitational Wave Network (LIGO-Virgo-KAGRA). Using the RIFT parameter inference engine, we employ two independently implemented waveform models (SEOBNRv5EHM and TEOBResumS-Dali) which account for orbital eccentricity and the effects of aligned compact object spins. Using these two waveforms, we find consistent conclusions that disfavor the eccentric hypothesis. Unlike previous work, among binary BLACK HOLE candidates, we find potential evidence for eccentricity in three events: GW200129, GW231001, and GW231123. For the latter two events, the evidence for eccentricity is ambiguous, with different degrees of support from different waveforms. Consistent with previous work, we find conclusions obtained about GW200129 can be sensitive to analysis settings, as expected, given the nonstationary noise present.
arXiv:2605.12973 [pdf, ps, other]Active galactic nucleus (AGN) feedback is a key ingredient in galaxy evolution, yet its impact on the cold atomic gas reservoir -- the neutral hydrogen (HI) phase -- remains poorly constrained. We present the most extensive spatially resolved HI 21-cm survey of Seyfert AGN hosts to date, based on observations with the Giant Metrewave Radio Telescope (GMRT). Our high-resolution HI maps of eight Seyfert galaxies reveal detailed kinematics and surface density distributions of their atomic gas disks. We find that AGN-host galaxies exhibit a slightly shallower HI mass-size relation than the canonical relation or the SIMBA simulation predictions; however, the measured slope remains consistent with the canonical value within $2σ$ uncertainties. This result suggests that AGN feedback does not significantly disrupt the global extent or large-scale structure of atomic gas reservoirs. To investigate the internal HI kinematics in greater detail, we perform a 3D kinematic forward modeling of the HI disk in UGC 4503. Our analysis reveals an elevated intrinsic velocity dispersion of $σ= 14.9^{+6.1}_{-3.8}$ km/s and a reduced level of rotational support, with $V/σ= 14.28_{-4.17}^{+4.97}$, compared to large-sample star-forming spirals. These kinematic signatures, together with localized residuals in the velocity field, indicate that AGN-driven outflows or JETs may inject or indirectly affect the turbulence in the atomic gas disk, potentially regulating the cold gas reservoir. Future GMRT observations, combined with optical integral-field spectroscopy from MaNGA, will enable quantitative constraints on the role of AGN feedback in regulating STAR FORMATION efficiency across a larger and more representative galaxy sample.
arXiv:2605.13016 [pdf, ps, other]We revisit regular primordial vector modes sustained by the anisotropic stress of free-streaming neutrinos. We consider two classes of neutrino-sector initial conditions, the neutrino velocity isocurvature mode ($ν\mathrm{VI}$) and the neutrino octupole mode ($ν\mathrm{OCT}$). We update their observational constraints using current cosmological data, and examine the impact of including the BICEP/Keck 2018 $B$-mode POLARIZATION data. From an MCMC analysis, we obtain the 95\% C.L. upper bounds on the vector-to-scalar ratio as $r_\mathrm{v}<1.55\times10^{-4}$ and $r_\mathrm{v}<1.04\times10^{-2}$ for the $ν\mathrm{VI}$ and $ν\mathrm{OCT}$ modes at the vector pivot scale $k_{0} = 0.01\,{\rm Mpc}^{-1}$, respectively. We then study two consequences of these bounds. First, we estimate the MAGNETic fields inevitably generated in the pre-recombination plasma associated with the vector modes. We find that the MAGNETic-field amplitude at recombination with a coherent length of $1~{\rm Mpc}$ is bounded by $B\sim\mathcal{O}(10^{-23})\,{\rm G}$ and $B\sim\mathcal{O}(10^{-21})\,{\rm G}$ for the $ν\mathrm{VI}$ and $ν\mathrm{OCT}$ modes, respetively, which is too small to provide the seed of MAGNETic fields observed today. Second, assuming the helical vector mode, we compute the induced CMB $EB$ spectrum. We show that even a fully helical primordial vector mode cannot reproduce the currently observed $EB$ signal while remaining consistent with parity-even CMB constraints.
arXiv:2605.13056 [pdf, ps, other]This work is devoted to the study of the influence of temperature anisotropy and parallel heat flux on the stability of supersonic shear flow in collisionless plasmas. Within a fluid-based framework, we employ the 16-moment transport equations -- derived from the Vlasov-Maxwell system -- to describe the plasma dynamics. By performing a modal analysis we investigate the oblique propagation of linear disturbances within a MAGNETized plasma characterized by a shear flow of arbitrary profile aligned with the ambient MAGNETic field. In the unperturbed state, both the plasma density and the MAGNETic field are assumed to be homogeneous. For a smooth, hyperbolic velocity profile representing supersonic shear, the governing wave equation is reduced to a form amenable to an exact analytical solution. Analytical solutions are expressed in terms of special functions that yield an infinite discrete spectrum of complex eigenfrequencies ($n = 0, 1, 2, \dots$). The instability is identified as resonant, peaking when the wave phase velocity matches the mean flow velocity, with the growth rate decreasing for higher-order modes. The results indicate that, while heat flux exerts a negligible influence under conditions of supersonic flow, the growth rate decreases and approaches an asymptotic value as the Mach number increases. Notably, the instability vanishes in the vortex sheet limit, distinguishing it from the classical Kelvin-Helmholtz mechanism. These findings suggest that this specific instability holds significant potential for explaining the problem of observed boundaries between isotropic and anisotropic proton temperature regions in a low-beta solar wind plasma.
arXiv:2605.13065 [pdf, ps, other]This paper presents the design of a rapid cycling SYNCHROTRON (RCS) featuring a longitudinal localized kick driven fast extraction system for three-dimensional (3D) pencil beam scanning (PBS) proton FLASH delivery. The extraction method is designed to accommodate a novel scanning scheme that addresses the stringent requirement for substantially shorter delivery time compared to current solutions, where the scanning layer is parallel to the proton beam direction. In this method, the kicker pulse waveform is applied selectively to specific longitudinal segments of the proton bunch. For each scanning spot, the functional region of the kicker along the longitudinal direction is dynamically adjusted based on real-time beam longitudinal line density measured by a beam current monitor. The corresponding region-determination algorithm is provided. We analyze the spot dose accuracy and the beam loss at the septum, indentifying increased particle longitudinal line density will reduce spot dose accuracy and increase beam loss. A total number of particles of $2\times10^{10}$ can satisfy the requirements of spot dose accuracy and the beam loss due to the septum is less than 1%. The extraction system comprises a stripline kicker, an electric septum (ESe), and a MAGNETic septum (MSe), imposing specific requirements on the RCS lattice design. The RCS is carefully designed to meet these constraints, and the parameters of the extraction elements are detailed. By integrating a novel scanning scheme with a specially designed RCS and fast extraction method, this work demonstrates the feasibility of achieving 3D PBS proton FLASH delivery.
arXiv:2605.13459 [pdf, ps, other]We investigate the observational signatures of an idealized double-ring and double-torus system orbiting a Schwarzschild BLACK HOLE, allowing the two emitting components to have mutually inclined symmetry axes. Using general-RELATIVISTIC ray tracing, we construct frequency-shift maps, bolometric flux maps on the observer's screen, and the corresponding spectral line profiles of the emitted radiation. The single equatorial torus is used as a reference configuration in order to isolate the effect of the second emitting component and of the mutual misalignment of the two structures. We show that the presence of two non-coplanar emitting structures produces characteristic multi-peak spectral profiles and asymmetric bolometric-flux distributions. These signatures are imprinted both in the line-profile morphology and in the $α$-profiles of the bolometric flux, providing simple diagnostic features of non-coplanar multi-component accretion structures.
arXiv:2605.13654 [pdf, ps, other]We report the experimental characterization of free-surface deformations generated by three-dimensional homogeneous and isotropic turbulence. Using Fourier transform profilometry in a JET-forced turbulent tank, we perform spatiotemporal measurements of the surface elevation field over a wide range of turbulence intensities. The standard deviation of surface deformations scales linearly with subsurface velocity fluctuations. The spectra of surface deformations highlight the coexistence of two mechanisms: transient coherent structures (e.g., upwelling) contributing to the low-frequency, large-scale spectral components, and a passive response to subsurface turbulent pressure fluctuations responsible for the power-law spectral scaling. The wavenumber and frequency spectra of surface deformations exhibit similar power-law exponents (-2.5), suggesting the advection of turbulent structures at the free surface. We develop a linear response model based on the transfer function from the free surface to turbulent pressure fluctuations, incorporating wave-turbulent damping. The model successfully predicts the main features of the turbulent surface: spatiotemporal spectrum shape, similar spectrum power-law exponents (-7/3), and dominance of passive response over wave generation. These findings provide new insights into free-surface turbulence in regimes where turbulent velocities remain below the surface-breaking threshold.
arXiv:2605.13714 [pdf, ps, other]In a recent series of papers we developed a first-principle and gauge invariant approach to BLACK HOLE perturbation theory valid to any order. We included back reaction effects to tackle the situation of evaporating BLACK HOLEs and obtained an explicit expression for the dynamics of the reduced phase space to second order. The physics of evaporating BLACK HOLEs is in particular encoded by apparent horizons, an observer dependent generalisation of the event horizon. We determine the shape of the apparent horizon to second order in the perturbations. The area of the apparent horizon is an interesting observable which is expected to decrease in the quantum theory due to Hawking evaporation. We show how the full four dimensional metric can be reconstructed in terms of the reduced phase space variables. In the quantum theory, taking expectation values of this metric, we obtain an effective classical metric, whose causal structure can then be visualised in a quantum corrected Penrose diagram. We conclude with an outlook into the quantisation procedure in the reduced phase space formalism and the implications on the area of the apparent horizon.
arXiv:2605.13728 [pdf, ps, other]Title: Detector for fast wave trains in the solar radio emissionAuthors: V. A. Dmitriev, E. G. Kupriyanova, A. V. Mikhalchuk,Comments:Subjects: astro-ph.SRCreated: 2026-05-13; Updated: 2026-05-14; Datestamp: 2026-05-14Quasi-periodic fast propagating (QFP) wave trains observed in the solar corona after some energetic events (solar flares, coronal mass ejections, JETs) open possibilities for diagnostics of spatial and temporal scales of the impulsive energy release processes, that are absent in the standard model of a solar flare. Besides, the dynamics of the wave trains and their characteristic spatial and temporal signatures allow to localize the initial energy release volume magenta and to perform fine diagnostics of the transverse structures of plasma inhomogeneities in the solar corona. However, the small number of such events registered significantly limits their promising diagnostic potential. The aim of this paper is to perform an automatic search for fast wave trains in radio data. We apply classifying neural network/machine learning methods. Dynamic radio spectra obtained by HiRAS radio spectrographs within the 20 MHz -- 2.5 GHz frequency band during 2011 were used. We consider 50 global coronal EUV waves as marker events for more a targeted search in HiRAS data. Our automatic detector revealed 50 independent QFP-candidates events with the temporal signatures similar to that of the fast wave trains, with 13 candidates connected with the global waves.
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