Current date: 2026-06-11
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Datestamp limit: 2026-06-11 (0 days ago)
Created/updated limit: 2026-06-04 (7 days ago)
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Number of records retrieved: 726
Keyword score statistics
score 10 -- 1 abstracts
score 9 -- 1 abstracts
score 8 -- 2 abstracts
score 7 -- 1 abstracts
score 5 -- 3 abstracts
score 4 -- 6 abstracts
score 3 -- 11 abstracts
score 2 -- 19 abstracts
in total -- 44 abstracts
Articles that appeared on 2026-06-11
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[abstract 1 / 44] Wow! (score: 10)
- Title: Stellar mass loading drives dissipation and reacceleration in AGN JETs: Explaining VLBI-Gaia offsets and constraining JET powerAuthors: G. Fichet de Clairfontaine, M. Perucho, J. M. Martí, Y. Y. Kovalev,Comments: Accepted for publication in A&ASubjects: astro-ph.HECreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
Recent Very Long Baseline Interferometry (VLBI) and Gaia astrometry reveal systematic milliarcsecond-scale offsets between the radio and optical centroids of ACTIVE GALACTIC NUCLEi (AGN). These "radio-optical offsets" do not alter the standard opacity-driven interpretation of radio core shifts. Instead, they indicate that the optical emission centroid is frequently displaced downstream of the radio SYNCHROTRON optical depth $τ= 1$ surface, implying that additional dissipation and particle reacceleration occur beyond the opacity radio core within RELATIVISTIC JETs. We perform steady-state, axisymmetric RELATIVISTIC MAGNETohydrodynamic (RMHD) simulations of AGN JETs, including baryonic mass-load from stellar winds, varying JET kinetic power, and stellar core radius. Synthetic SYNCHROTRON emission maps in radio and optical bands are generated via a radiative transfer code, and centroid offsets are extracted for comparison with observations. Parsec-scale radio-optical offsets arise only for JET powers $L_{\rm j} \sim 10^{42.5} - 10^{44}\,\rm{erg}\,\rm{s}^{-1}$. In this regime, stellar winds trigger JET deceleration at intrinsic distances of a few $10^2-10^3\,\rm{pc}$, shifting the optical centroid downstream and producing offsets of $\sim 0.1 - 4\,\rm{mas}$ (a few tens of parsecs at $z=1$). Offsets depend on stellar distribution, viewing angle, and optical JET dominance, and vanish outside this power range. We reproduce the observed redshift evolution of offset incidence, linking it to the cosmic evolution of thermally pulsing asymptotic giant branch (TP-AGB) mass loss. Although stellar mass loading is unlikely to be the sole dissipation mechanism, its unavoidable presence in galactic nuclei makes it a natural baseline for energy dissipation. Radio-optical offsets therefore offer a constraint on AGN JET power and JET-host coupling, independent of traditional lobe-based methods.
[abstract 2 / 44] Wow! (score: 9) - Title: Gamma-Ray Constraints on Heavy Axion-Like-Particle Decays from FERMI-LAT and H.E.S.S. Blazar SpectraAuthors: A. Acharyya, F. Aharonian, M. Backes, R. Batzofin, Y. Becherini, S. Bisero, M. Böttcher, C. Boisson, J. Bolmont, F. Brun, C. Burger-Scheidlin, T. Bylund, S. Casanova, D. Cecchin Momesso, M. Cerruti, A. Chen, M. Chernyakova, J. O. Chibueze, O. Chibueze, T. Collins, B. Cornejo, G. Cotter, G. Cozzolongo, J. de Assis Scarpin, M. de Naurois, E. de Oña Wilhelmi, A. Deka Baruah, A. Dmytriiev, K. Egberts, K. Egg, C. Escañuela Nieves, K. Feijen, M. D. Filipović, G. Fontaine, S. Funk, S. Gabici, Y. A. Gallant, M. Genaro, P. Geneste, J. F. Glicenstein, P. Goswami, C. Grimaud, L. Heckmann, B. Heß, J. A. Hinton, W. Hofmann, T. L. Holch, M. Holler, M. Jamrozy, F. Jankowsky, I. Jaroschewski, I. Jung-Richardt, D. Kerszberg, B. Khélifi, N. Komin, D. Kostunin, R. G. Lang, S. Lazarević, M. Lemoine-Goumard, J. -P. Lenain, P. Liniewicz, A. Luashvili, J. Mackey, D. Malyshev, D. Malyshev, V. Marandon, M. G. F. Mayer, A. Mehta, M. Meyer, A. M. W. Mitchell, R. Moderski, L. Mohrmann, A. Montanari, E. Moulin, J. Niemiec, L. Olivera-Nieto, M. O. Moghadam, M. Panter, R. D. Parsons, D. Pastuszka Malek, P. Pichard, S. Pita, S. Porras-Bedmar, T. Preis, G. Pühlhofer, M. Punch, A. Quirrenbach, A. Reimer, O. Reimer, H. X. Ren, B. Reville, F. Rieger, G. Roellinghoff, G. Rowell, B. Rudak, K. Sabri, V. Sahakian, A. Santangelo, M. Sasaki, F. Schüssler, J. N. S. Shapopi, W. Si Said, Ł. Stawarz, R. Steenkamp, S. Steinmassl, T. Tanaka, A. M. Taylor, G. L. Taylor, R. Terrier, Y. Tian, T. Unbehaun, C. van Eldik, M. Vecchi, J. Vink, V. Voitsekhovskyi, T. Wach, S. J. Wagner, A. Wierzcholska, M. Zacharias, A. Zech, W. Zhong,Comments: 27 pages, 9 figures, Prepared for submission to JCAPSubjects: astro-ph.HE astro-ph.COCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
The propagation of very-high-energy (VHE; $E_γ \geq 100$ GeV) gamma rays from extragalactic sources is affected by interactions with photons of the extragalactic background light (EBL), resulting in pair production that attenuates the intrinsic gamma-ray flux. This interaction renders the Universe increasingly opaque to VHE photons at high energies and redshifts. New physics scenarios involving axion-like particles (ALPs) could modify this expected optical depth. In particular, ALPs with masses $m_a \sim 10$ eV can decay into two photons over cosmological timescales, thereby contributing to the diffuse EBL. If such ALPs constitute a significant fraction of the DARK MATTER density, their decay would enhance the EBL intensity and consequently increase the gamma-ray optical depth. In this study, we investigate this scenario using a large sample of gamma-ray spectra observed with the High Energy Stereoscopic System (H.E.S.S.) and the FERMI Large Area Telescope. We model the contribution of decaying ALPs to the EBL and assess their impact on the spectra of BLAZARs across redshifts. By comparing these observations with standard EBL models, we place constraints on the properties of heavy ALPs, specifically their mass and photon coupling, and evaluate their viability as a DARK MATTER candidate capable of modifying the gamma-ray transparency of the Universe. From the combined analysis, and under the assumption that ALPs constitute the entire DARK MATTER density, we derive 95% confidence exclusion limits on the photon-ALP coupling down to $g_{aγ} \sim 7 \times 10^{-12}$ GeV$^{-1}$ for masses $m_a\sim 15$ eV. These constraints are competitive with existing astrophysical bounds and provide complementary sensitivity to other techniques, closing a previously unconstrained region of parameter space in the $m_a \sim 2.5$-$20$ eV range.
[abstract 3 / 44] Wow! (score: 8) - Title: Ring Position Angles and Spin in M87* and Sgr A*Authors: Nicholas S. Conroy, Michi Bauböck, Vadim Bernshteyn, Paul Tiede, Abhishek V. Joshi, Cora Prather, Charles F. Gammie,Comments: Submitted to OJAp (14 pages, 9 figures, 1 table)Subjects: astro-ph.HECreated: 2026-06-09; Updated: 2026-06-11; Datestamp: 2026-06-11
Event Horizon Telescope (EHT) images of BLACK HOLEs appear as rings with a brightness asymmetry. Here, we expand on our previous study of the asymmetry magnitude $a_1$ to study the position angle of the peak brightness asymmetry $\mathrm{PA}_1$ in general RELATIVISTIC MAGNETohydrodynamic (GRMHD) models. For larger spin magnitudes ($a_{*}>0$ and $a_{*}\lesssim-0.5$), the mean $\mathrm{PA}_1$ falls within $1σ$ of the approaching limb of the BLACK HOLE, regardless of viewing inclination, disk MAGNETization, or source. By comparing the $(a_1, \mathrm{PA}_1)$ distribution in M87* observations with models, we demonstrate that we can mildly disfavor low-magnitude spins and strongly disfavor all spin vectors that point toward Earth. The alignment of $\mathrm{PA}_1$ relative to the large-scale JET axis may suggest that M87*'s disk does not have a large tilt. By combining $\mathrm{PA}_1$ with the pattern speed measured in optimistic 2026 M87* video conditions, the EHT can constrain whether M87* is prograde or retrograde with $\sim 84\%$ accuracy. In Sgr A*, we show that a detection of $(a_1, \mathrm{PA}_1)$ could constrain the magnitude and direction of the galactic center spin vector. Finally, if future EHT expansions increase the sample of horizon-scale sources, a simple set of observables (ring diameter, asymmetry magnitude, and asymmetry angle) could enable robust constraints on BLACK HOLE mass, spin, and inclination.
[abstract 4 / 44] Wow! (score: 8) - Title: A Jet from a Nearly Dormant Black HoleAuthors: Xiaopeng Cheng, Hai Yang, Jun Yang, Xiaofeng Li, Feng Yuan, Rusen Lu, Hyunwook Ro, Bong Won Sohn, Lulu Fan, Yihang Zhang, Wen Chen, Niu Liu, John E. Conway, Taehyun Jung,Comments: 36 pages, 9 figures, 4 tables, comments welcome!Subjects: astro-ph.HE astro-ph.GACreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
Most galaxies host supermassive BLACK HOLEs (SMBHs) that remain weakly accreting or dormant for much of their lifetimes. At the lowest accretion rates, these systems may represent the transition between active nuclei and dormant BLACK HOLEs, but whether they can still launch collimated JETs remains unclear. The nuclei in our Galaxy (\sgra) and M31 are key examples of this regime, although no clear JET structure has yet been detected in either source. Here we report multi-frequency very long baseline interferometric observations of \Msixty\ (NGC~4649), a nearby elliptical galaxy hosting a nearly dormant SMBH with an Eddington ratio of $\sim10^{-8}$. We detect a compact two-sided JET with an unusually steep SYNCHROTRON spectrum, demonstrating that collimated outflows can persist even under nearly dormant accretion conditions. The apparent radio core exhibits an unprecedentedly steep frequency-dependent position shift toward the SMBH, locating the central engine only $\sim57\,μ$as, corresponding to a projected distance of $\sim10$ Schwarzschild radii, upstream of the 8.37-GHz core. The observed JET morphology and steep core-shift behaviour are reproduced by general RELATIVISTIC MAGNETohydrodynamic and radiative-transfer simulations, indicating a MAGNETically dominated, non-equipartition JET-launching region that departs from the standard conical equipartition picture. These results provide direct observational evidence that JET production can survive near the dormant SMBHs and establish \Msixty\ as a unique laboratory for probing JET formation on event-horizon scales in the lowest-accretion SMBH regime.
[abstract 5 / 44] Wow! (score: 7) - Title: Flagging Super-Eddington Candidates among Jetted, γ-Ray-Emitting AGNAuthors: Paola Marziani, Benedetta Dalla Barba, Luigi Foschini,Comments: 8 pages, 1 figure, submitted as a proceedings paper to Physical Science ForumSubjects: astro-ph.GA astro-ph.HECreated: 2026-06-09; Updated: 2026-06-11; Datestamp: 2026-06-11
The QUASAR Eigenvector-1/Main Sequence (E1/MS) provides a physically motivated empirical framework to organize the spectroscopic diversity of type~1 ACTIVE GALACTIC NUCLEi (AGN). In its optical plane, the full width at half maximum of H$β$ and the Fe\,II strength ratio $R_{\mathrm{FeII}}$ define a sequence that is primarily driven by Eddington ratio, with important secondary roles played by black-hole mass, orientation, spectral energy distribution, and chemical enrichment. The E1/MS framework is therefore well suited to identify highly accreting and possibly super-Eddington (SE) sources, usually associated with the extreme Population~A (xA) spectral types. We discuss why E1/MS is a useful tool to search for SE accretors among JETted AGN and, conversely, to place $γ$-ray-detected AGN in the broader context of QUASAR phenomenology. We summarize two complementary results: (1) some candidate SE accretors show radio properties such as high brightness temperature non-thermal cores or radio lobes} consistent with JET activity; and (2) a subset of low-redshift $γ$-ray narrow-line Seyfert~1 galaxies exhibit optical spectra consistent with xA or borderline-xA classification. We also expand the discussion of recent developments in E1/MS studies, including metallicity trends, the spectral energy distribution of xA QUASARs, and the role of highly accreting QUASARs as discovery tools for extreme accretion states, as probes of QUASARs at the reionization epoch, and as possible cosmological probes.
[abstract 6 / 44] Yes (score: 5) - Title: X-ray variability of SDSS J000532.84+200717.4: from a normal state to an X-weak stateAuthors: Xiaohui Yang, Yanli Ai, Liming Dou, Tinggui Wang, Chichuan Jin, Wenfeng Wen, Xu Zhang, Yuming Fu, Jinhong Chen, Ning Jiang, Fukun Liu,Comments: ApJ, acceptedSubjects: astro-ph.GA astro-ph.HECreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
We present a multi-epoch study of the extreme X-ray variability of the type~1 QUASAR SDSS~J000532.84+200717.4 using archival observations from \textit{XMM-Newton}, \textit{SWIFT}/XRT, \textit{EP-FXT}, and \textit{ROSAT}, together with new optical spectroscopy and multi-wavelength photometry. The 0.2--10~keV X-ray flux exhibits a transition from a high state to a subsequent low state, declining by more than an order of magnitude and placing the source in the X-ray--weak regime ($Δα_{\rm ox} \lesssim -0.3$). Significant variability on timescales of days to weeks persists within the low state. In contrast, the optical and mid-infrared emission remain stable over decade-long timescales, while the UV continuum varies only mildly and broadly tracks the X-ray evolution. Multi-epoch optical spectroscopy shows no significant long-term changes in either the continuum shape or the broad emission-line profiles. The \ion{Mg}{2} emission is relatively weak compared with typical QUASARs, suggesting similarities to weak-line QUASARs. The pronounced wavelength-dependent variability indicates that the accretion disk remains largely intact while the X-ray emission undergoes dramatic changes. The spectral hardening in the low state and the viability of ionized partial-covering models are consistent with variable, largely dust-free absorbing gas, possibly associated with clumpy inner disk winds, although intrinsic coronal variations cannot be excluded. SDSS~J0005+200717.4 therefore provides evidence that extreme X-ray weakness can arise as a transient phase in otherwise normal QUASARs.
[abstract 7 / 44] Yes (score: 5) - Title: Centrifugal instability of compressible flows and the hydrodynamic stability of accretion disksAuthors: Serguei S. Komissarov, Konstantinos N. Gourgouliatos,Comments: Accepted for publication in MNRASSubjects: astro-ph.HECreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
A recent analysis of the centrifugal instability in the case of pressure-supported compressible RELATIVISTIC rotation, with application to astrophysical JETs, yielded a generalisation of the famous Rayleigh criterion for Newtonian flows. According to this criterion, the centrifugal instability is strongly affected by the flow Mach number, and not only in the RELATIVISTIC fluid dynamics but also in its Newtonian limit. To validate the Newtonian version of this criterion, we performed axisymmetric numerical simulations of non-RELATIVISTIC transonic rotating flows which are stable according to the original Rayleigh criterion but can be either stable or unstable according to the new one. The results of computer simulations are found to be in perfect agreement with the theory. The hydrodynamic stability of accretion disks is often explained by referring to the original Rayleigh criterion, even if their rotation is highly supersonic. To clarify the matter, we analysed the hydrodynamic stability of flows rotating about central compact object and derived an instability criterion that retains the explicit dependence on the flow Mach number. This criterion turns out to be equivalent to the standard Solberg-Høiland criterion, which does not involve the Mach number. The same applies to the case of pressure-supported rotation, where the role of gravity is played by the centrifugal force.
[abstract 8 / 44] Yes (score: 5) - Title: Detection of a parsec-scale, compact, and fading ejecta from an accreting massive BLACK HOLEAuthors: Chao Li, Ning Chang, Jun Yang, Lang Cui, Luis C. Ho,Comments: 5 pages, 3 figuresSubjects: astro-ph.HE astro-ph.GACreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
Dwarf galaxies, characterized by their low luminosities and masses, are excellent candidates for searches for intermediate-mass BLACK HOLEs (IMBHs), particularly when they show strong accretion and ejection activity. The dwarf galaxy SDSS J101747.09+393207.7 has recently been found to display a very high X-ray luminosity and an X-shaped optical structure, possibly caused by a dwarf--dwarf merger. To explore its potential IMBH ejection activity, we performed very long baseline interferometry (VLBI) observations at 4.9 GHz. In this work, we present the detection of a milliarcsecond-scale, compact, sub-microjansky radio component near the optical centroid. According to some existing radio sky survey data, the radio component was not detected until 2015; it displayed an optically thin steep radio spectrum and declining flux densities across 0.8--5 GHz from 2019 to 2025. Therefore, we identify it as a short-lived and rarely seen ejecta that was produced by unstable accretion onto a massive BLACK HOLE and likely faded away in a few decades. These results indicate that short-lived, episodic JET activity from accreting IMBHs in dwarf galaxies might exist.
[abstract 9 / 44] Yes (score: 4) - Title: Charged particle dynamics in MAGNETosphere generated by current loop around Schwarzschild BLACK HOLEAuthors: Martin Kološ, David Kofroň,Comments: Code in Mathematica generating figures for this article: https://github.com/XyhwX/articles_codesSubjects: gr-qc astro-ph.HECreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
We present a theoretical study of the MAGNETic field generated by a toroidal current loop situated in the equatorial plane of a non-rotating Schwarzschild BLACK HOLE, based on the dynamics of charged particles. Using the exact general RELATIVISTIC solution for the MAGNETic field, we analyze particle motion both analytically and numerically, identifying regions of stable and unstable orbits. In particular, we classify charged particle dynamics into attractive and repulsive Lorentz force configurations and show that in the attractive case, charged particles can accumulate near the current loop, forming collective currents that oppose the original current loop MAGNETic field. We demonstrate that charged particle accumulation can lead to the formation of toroidal structures analogous to radiation belts in the BH MAGNETosphere. We compare the curved spacetime solution to flat spacetime analogs and highlight general RELATIVISTIC effects such as the existence of the innermost stable circular orbit for charged particles, which sets a lower bound for radiation belt formation. The divergence of the vector potential at the loop location in the idealized infinitesimal loop model is addressed, and we argue that a physically realistic model must consider a finite-width current distribution to avoid unphysical divergences in the effective potential.
[abstract 10 / 44] Yes (score: 4) - Title: Comisso-Asenjo Mechanism in Rotating $\mathcal{N}=2,U(1)^2$ Gauged Supergravity Black Holes: Extended Comparison With Kerr Black HoleAuthors: Abhinav Jaguri, Hemwati Nandan, Pankaj Sheoran, Sanjar Shaymatov,Comments: 28 pages, 13 captioned figures and 3 tablesSubjects: gr-qc astro-ph.HECreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
In this paper, we investigate energy extraction via the Comisso-Asenjo (CA) MAGNETic RECONNECTion process near a coupled $\mathcal{N}=2,\,U(1)^2$ gauged supergravity Black Hole (BH). Our study focuses on the combined impact of the independent parameter set $p_i\in(N_g,g,v,e)$ with the spin parameter $a$ on the extracted energy ($ε_{\pm}$), efficiency ($η$), and extracted power ($\mathcal{P}_{CA}$), aiming to identify optimal combinations where energy can be extracted with higher efficiency in certain cases at lower spin $(a\sim0.39)$ than the Kerr extremal case $(a\sim1)$. Using the spacetime parameters, we explore various cases leading to distinct spacetimes and provide an extended comparison with the Kerr Black Hole (KBH). We also examine the influence of the orientation angle ($ξ$) and MAGNETization parameter ($σ_0$) on both efficiency and extracted power. Investigating low $[\,\forall p_i<0.2 \land N_g<0.08\,]$, mid $[\,\exists p_i\ge0.5 \land N_g\in(0.08,0.15)\,]$, high $[\,\exists p_i>0.7 \land N_g\in(0.16,0.23)\,]$, and mixed $[\,\forall p_i\in(0,1) \land N_g\in(0,0.23)\,]$ parameter combinations, we explore only extremal cases for all spacetime parameters and demonstrate that the extremal Kerr efficiency limit ($η>1.495$) can be exceeded. The statistical Kendall's Tau approach allows us to identify the key independent parameters acting as boosters or dampers in the energy extraction process and to visualize the relationship between $(N_g,g,v,e)$ and the physical outputs $(a_{\rm ext},r_E,r_{\rm ergo},ε_{\pm},η,\mathcal{P}_{CA},R_η,R_{\mathcal{P}})$. Furthermore, we show that the observable Lundquist number $S_{\rm obs}$ in rotating BH spacetimes acquires an observer-dependent angular dependence through the lapse function $(α)$. This leads to deviations from the standard Sweet-Parker scaling when expressed in terms of observable quantities.
[abstract 11 / 44] Yes (score: 4) - Title: Extreme, transient bursts of energy in the auroral ionosphere. II. A MAGNETotail diPOLARIZATION eventAuthors: Magnus F Ivarsen, Yukinaga Miyashita, Brian Pitzel, Jean-Pierre St-Maurice, Jaeheung Park, Devin R Huyghebaert, Yangyang Shen, Glenn C Hussey,Comments: 38 pages, 14 figuresSubjects: physics.space-ph astro-ph.EP physics.plasm-phCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
We report ground-based coherent VHF radar observations of extreme turbulent field-structures detected in coincidence with a MAGNETospheric substorm-associated MAGNETotail diPOLARIZATION. The field-structures are observed by the ICEBEAR radar, in the form of Farley-Buneman (FB) waves in the auroral electroJETs, and the field-structures themselves move an order of magnitude faster than the saturation speed of the underlying FB waves, implying transient electric field sources up to 330 mV/m in strength. The field-structures are identified and automatically tracked using an unsupervised clustering & tracking algorithm, applied to clutters of ICEBEAR radar backscatter targets, a method that turns the Doppler radar into a tracking radar capable of measuring the ionospheric ExB-drift by proxy. We place this finding in a coordinated multi-instrument context. Three THEMIS spacecraft observed the diPOLARIZATION event in-situ in the near-Earth plasma sheet. In the ionosphere, Swarm A, crossing through the guilty auroral arc at the onset of the diPOLARIZATION event, recorded clear signatures of propagating Alfvén waves threading the relevant flux tube. We interpret the ICEBEAR transients as the natural ionospheric foot signature of a shear Alfvén pulse launched by the bipolar space-charge (Hall) electric field of the thinned current sheet, with amplification along the converging flux tube, partial reflection at the ionospheric boundary, and spatial sharpening by precipitation-produced Pedersen-conductance gradients on the auroral arc edges. A one-dimensional wave-transmission analysis recovers the observations. Our results elucidate a tightly controlled coupling between MAGNETotail processes and meter-scale auroral plasma turbulence, and demonstrate the capability of ICEBEAR to resolve extreme, transient electric-field enhancements in the ionosphere.
[abstract 12 / 44] Yes (score: 4) - Title: Protostellar Outflows at the EarliesT Stages (POETS). IX. Magnetohydrodynamic disk winds traced by SO and SO$_2$ in luminous protostarsAuthors: L. Moscadelli, H. Beuther, A. Sanna, M. T. Beltrán, C. Gieser, Th. Henning, P. D. Klaassen, R. Kuiper, S. Leurini, T. Möller, A. Palau, R. E. Pudritz, Á Sánchez-Monge, D. Semenov, J. S. Urquhart, H. Zinnecker,Comments: 12 pages with 5 figures (plus Appendix of 4 pages), accepted for publication in A&ASubjects: astro-ph.SR astro-ph.GACreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
We investigate two massive young stellar objects (YSOs), IRAS21078+5211 and G035.02+0.35, where evidence for MAGNETohydrodynamic (MHD) disk winds (DWs) has been obtained at scales of 10-100 au through measurements of the 22GHz water maser velocity distribution within the Protostellar Outflows at the EarliesT Stages (POETS) survey. We employ IRAM Northern Extended Millimeter Array and archival Atacama Large Millimeter Array observations of IRAS21078+5211 and G035.02+0.35, respectively, to study kinematics and physical conditions of the corresponding protostellar winds on scales of 100-1000 au using the same molecular tracers. In IRAS21078+5211, the emissions of several molecules, particularly SO, SO2, CH3CN and CH3OH, are distributed along the axis of the radio JET, and present a LSR velocity (Vlsr) gradient transversal to the JET axis. Position-velocity (PV) plots of the SO lines show patterns consistent with Keplerian rotation. The SO2 emission comes from high velocity gas flowing close to the JET axis, while CH3CN and CH3OH present larger radial extension than the S-bearing species. In G035.02+0.35, the same molecules are instead distributed along the major axis of the rotating disk, and their Vlsr gradients consistently trace the disk rotation. The corresponding PV plots present Keplerian profiles. SO is the only molecular species whose emission extends well outside the disk. In both YSOs, the spatial and velocity distributions of SO are consistent with a rotating wind MAGNETo-centrifugally launched from the YSO disk. The comparison with models of molecule formation and excitation in shocks indicates that the different radial extension of the molecular species observed in the protostellar wind of IRAS21078+5211, as well as the lack of molecules, except SO, in the G035.02+0.35's wind, can be explained in terms of a radially extended MHD DW, rather than a compact X-wind.
[abstract 13 / 44] Yes (score: 4) - Title: X-ray luminosity function of Compton-thick AGN in the early Universe (z > 3). Robustness and biases of the CTK populationAuthors: Angel Ruiz, Ektoras Pouliasis, Ioannis Georgantopoulos,Comments: 19 pages, A&A AcceptedSubjects: astro-ph.GACreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
The population of Compton-thick (CTK) AGN represents a critical yet elusive phase in the growth of supermassive BLACK HOLEs. Constraining their abundance and evolution at high z is essential for understanding both SMBH growth and the origin of the cosmic X-ray background. We investigate the X-ray luminosity function (XLF) of CTK AGN at z > 3 using one of the largest available samples of X-ray-selected AGN at high z, containing 811 sources from XMM-Newton XXL-N and Chandra CCLS and CDF-S/N surveys. We first selected a subsample of ten high-probability CTK candidates, identified through x-ray spectral fitting. Their multiwavelength properties are examined through SED modelling to assess the robustness of their CTK classification. For most sources, the inferred X-ray luminosities appear overestimated when compared with their IR luminosities. After updating the NH posteriors with IR-informed priors, only three sources remain consistent with the CTK regime. To compute the XLF for the entire CTK AGN population, we used 24 microns photometry to estimate IR luminosities and update the X-ray posteriors for all the remaining sources. Incorporating IR priors systematically reduces the inferred CTK number densities, yielding a more conservative and physically consistent estimate of the XLF. We find that CTK AGN constitute 17 per cent of the total AGN population at 3 < z < 6, consistent with results at lower z. Our analysis reveals no statistically significant evolution in the CTK fraction up to z about 6, suggesting that the most heavily obscured accretion phase remains a persistent component of BLACK HOLE growth throughout cosmic history. While the overall obscured AGN fraction (NH > 1e23 cm-2) increases toward higher redshifts, the stable CTK fraction supports the interpretation that, at these epochs, the interstellar medium in typical host galaxies cannot produce CTK levels of obscuration.
[abstract 14 / 44] Yes (score: 4) - Title: SN 1006: A Cosmic Laboratory for Investigating Shock Acceleration PhysicsAuthors: Emma McGinness, Rebecca Diesing, Damiano Caprioli, Fabio Acero,Comments:Subjects: astro-ph.HECreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
SN 1006 is a historical Type Ia SUPERNOVA remnant that exhibits non-thermal emission ranging from radio to multi-TeV $γ$-rays. Most of this emission (particularly X-rays and $γ$-rays) is concentrated in polar caps aligned with the ambient MAGNETic field, which makes it an ideal laboratory for studying COSMIC RAY (CR) acceleration at different shock obliquities and the hadronic/leptonic nature of the $γ$-ray emission. We model SN 1006's morphology, multi-wavelength spectrum, and radial profile using a self-consistent multi-zone kinetic model of particle acceleration that accounts for: CR-driven shock modification, MAGNETic field amplification, drift in MAGNETic fluctuations, and temporal dynamics including adiabatic and SYNCHROTRON losses. Our model can reproduce both the observed spectral and spatial properties, with the exception of the radio profile that we argue requires 3D hydrodynamic effects to replicate. We find that quasi-parallel regions (where the shock normal aligns with the ambient MAGNETic field) exhibit very prominent CR acceleration ($\sim$20% efficiency), while quasi-perpendicular regions exhibit efficiencies below 1%, consistent with the results of kinetic simulations. We also find that electrons are responsible for the majority of the $γ$-ray emission from SN 1006 (i.e., it is a leptonic source), with the exception of the northwest region due to an encounter with a dense cloud.
[abstract 15 / 44] (score: 3) - Title: Milliarcsecond-scale spectrum of the persistent radio source associated with FRB 20190417A and constraints for FRB 20181030AAuthors: G. Bruni, L. Piro, Y. -P. Yang, L. Nicastro, A. Rossi, E. Palazzi, E. Maiorano, S. Savaglio, B. Zhang,Comments: Accepted for publication in A&A LettersSubjects: astro-ph.HE astro-ph.SRCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
We aim to confirm the compact nature and constrain the radio spectra of candidate persistent radio sources (PRSs) associated with repeating fast radio bursts (FRBs). We performed European VLBI Network (EVN) observations at 5 and 8 GHz targeting two candidates identified in a recent VLA survey. We measured flux densities and upper limits at milliarcsecond resolution and combined them with published VLBI data at lower frequencies to derive spectral constraints. We detect a compact source associated with FRB 20190417A at 5 GHz with a flux density of $150\pm45$ uJy, while no detection is obtained at 8 GHz. The source is unresolved and has a brightness temperature $T_{\rm b}>10^{5}$ K, confirming its non-thermal nature. Combining our measurement with VLBI data at 1.4 GHz, we derive a spectral index $α= -0.19 \pm 0.29$, consistent with a nearly flat spectrum. This makes FRB 20190417A only the second PRS with a spectral index constrained using VLBI data. The inferred luminosity places the source on the proposed $L_ν$-|RM| relation. Including this source yields a scatter of $σ_Δ= 0.65$, corresponding to $\hatα|ε| = 1.5 \pm 0.7$, consistent with forward shocks in the free-expansion phase or young pulsar wind nebulae. For the candidate PRS associated with FRB 20181030A, we report upper limits of 80 uJy at 5 GHz and 150 uJy at 8 GHz, corresponding to $L_{5\,\mathrm{GHz}} \lesssim 3.8 \times 10^{25}\ {\rm erg\ s^{-1}\ Hz^{-1}}$, and implying a steep spectral index ($α\lesssim -1.2$) if the VLA emission arises from a compact component. Our results highlight the importance of VLBI in isolating compact emission from FRB engines and provide one of the few spectral constraints for PRSs at milliarcsecond resolution. The consistency of FRB 20190417A with the $L_ν$-|RM| relation supports a nebular origin for the persistent emission.
[abstract 16 / 44] (score: 3) - Title: Minor Merger, Major Growth: An Overmassive, Highly Accreting Black Hole Powering a Secondary AGN In a Cosmic Noon Minor MergerAuthors: Marko Mićić,Comments: 6 pages, 2 figures. Accepted for publication in ApJSubjects: astro-ph.HECreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
We report the discovery of a spectroscopically confirmed z = 1.824 minor merger with a mass ratio of ~35:1 in which the secondary (smaller) galaxy hosts a luminous AGN. The system is identified in the 3D-HST survey and exhibits clear tidal features in James Webb Space Telescope imaging, confirming an ongoing interaction. Using archival Chandra X-ray observations, we detect 121 +/- 11 X-ray counts associated with the secondary galaxy, corresponding to a rest-frame 2-10 keV luminosity of L_X ~ (9 +/- 0.1) x 10^43 erg/s and a photon index of Gamma ~ 2.0-2.3. Analysis of the HST/WFC3 G141 grism spectrum yields an [O III] lambda5007 luminosity of (2 +/- 0.5) x 10^42 erg/s. Independent bolometric luminosity estimates from X-ray and [O III] emission are consistent, implying L_bol ~ (3-7) x 10^45 erg/s. Assuming standard BLACK HOLE-galaxy scaling relations, the expected BLACK HOLE mass is ~2 x 10^6 M_sun, which would require extreme super-Eddington accretion to explain the observed luminosity. On the other hand, assuming Eddington-limited or moderately sub-Eddington accretion implies a BLACK HOLE mass more than an order of magnitude above expectations. The observed X-ray spectral slope disfavors low accretion rates, restricting the allowed parameter space to high lambda_Edd and elevated BLACK HOLE masses. We conclude that the secondary AGN must be powered by an overmassive, highly accreting BLACK HOLE, providing direct observational support for theoretical predictions that minor mergers can drive rapid BLACK HOLE growth in secondary, smaller companions.
[abstract 17 / 44] (score: 3) - Title: A MAGNETar formation in binary neutron star mergerAuthors: Kenta Kiuchi, Alexis Reboul-Salze, Yuichiro Sekiguchi, Masaru Shibata,Comments: 4 pages, 4 figures, Supplemental MaterialSubjects: astro-ph.HE gr-qcCreated: 2026-06-09; Updated: 2026-06-11; Datestamp: 2026-06-11
We conduct a global general RELATIVISTIC neutrino-radiation-transfer MAGNETohydrodynamics simulation of a $1.35$-$1.35M_\odot$ binary neutron star with the unprecedented spatial resolution of $6.25$\,m on the Japanese supercomputer FUGAKU. The total consumed CPU time is $\approx 530$ million core hours. We initialize the binary neutron star's MAGNETic field to be $3.16\times 10^{12}$~G at maximum, which is compatible with the upper end of the observed binary pulsars. We demonstrate that the Kelvin-Helmholtz instability that emerges when the two neutron stars touch amplifies the MAGNETic field to an expected electroMAGNETic saturation energy of $\sim 10^{50}$~erg within $3$~ms after the merger. The spectral analysis indicates that the Kazantsev and Kolmogorov spectra are reproduced in the MAGNETic and kinetic power spectral densities, respectively. We also find that it induces stellar-scale MAGNETic field amplification by at least a factor of $316$. We conclude that a MAGNETar may form at least temporarily following neutron star mergers in a few ms.
[abstract 18 / 44] (score: 3) - Title: Imprints of the Neutral Interstellar Medium on Polarized Synchrotron Emission and Faraday RotationAuthors: Minjie Lei, S. E. Clark, Mehrnoosh Tahani, A. Bracco, Yik Ki Ma, Amit Seta, Jennifer West, E. Carretti,Comments:Subjects: astro-ph.GACreated: 2026-06-09; Updated: 2026-06-11; Datestamp: 2026-06-11
The interstellar medium (ISM) is a complex, multiphase medium, where disentangling the distribution of gas and MAGNETic field structure across different phases remains a considerable challenge. Recently, Faraday tomography enabled by broadband polarized radio observations has emerged as a promising probe of 3D ISM gas and MAGNETic field structures. However, the interpretation of these observations is obscured by our limited understanding of the different ISM components probed by the distinct Faraday depth features. In this work, we present a comprehensive multi-frequency ($\sim$300 MHz - 23 GHz) analysis comparing features in the Faraday-rotated, polarized SYNCHROTRON emission and HI structures over the full high-latitude (|b|>30 degrees) diffuse sky. Using measures of HI structure complexity along the line of sight (LOS), we observe enhanced dePOLARIZATION across SYNCHROTRON radio frequencies in regions with high HI complexity characterized by multiple HI velocity components. We also find that the first and second moments of the Faraday depth spectra are linked to the underlying neutral gas structure. These results indicate that regions of the ISM that are dominated by neutral gas could directly contribute a significant portion of the diffuse SYNCHROTRON emission and Faraday rotation. These findings establish new observational constraints for Galactic MAGNETic field models that synthesize multiphase tracers into a single coherent picture.
[abstract 19 / 44] (score: 3) - Title: Quasinormal modes and tidal responses of BLACK HOLEs in generic anisotropic matter environmentsAuthors: Yu-Qian Zhao, Paolo Pani,Comments: 14 pages, 3 figuresSubjects: gr-qc astro-ph.HECreated: 2026-06-09; Updated: 2026-06-11; Datestamp: 2026-06-11
We develop a perturbative framework for a BLACK HOLE embedded in a generic, possibly anisotropic, matter environment under spherical symmetry. Our approach extends previous analyses restricted to vanishing radial pressure or to perturbative matter configurations. Within this framework, we derive an analytical generalization of the Einstein cluster that incorporates a polytropic radial pressure, and we investigate the properties of this solution. We show that both the geodesic structure and the axial quasinormal-mode spectrum remain predominantly governed by an overall gravitational redshift effect, while the radial pressure systematically enhances the environmental corrections. In contrast, the tidal Love numbers are substantially more sensitive, and can exhibit order-unity deviations, including vanishing and negative strictly static MAGNETic Love numbers for sufficiently large anisotropy. We present the full linearized equations, which can be applied to various extensions, including ringdown analysis and extreme-mass-ratio inspirals.
[abstract 20 / 44] (score: 3) - Title: Spectral study of X-ray sources in some galaxies recently observed by ChandraAuthors: Amom Lanchenbi Chanu, Anoubam Senorita Devi,Comments: Published in Indian Journal of PhysicsSubjects: astro-ph.HECreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
With the aim to study the spectral properties of some X-ray sources from recently observed {\it Chandra} data, 9 galaxies which have been observed by {\it Chandra} ACIS-S during the year 2018 to 2022 have been considered for the present work. 27 sources with net source counts $ \ge$ 100 have been considered. The spectra of all the sources were fitted using two empirical models -- an absorbed powerlaw and an absorbed disk blackbody. From their estimated bolometric luminosities, the 27 X-ray sources are categorized as 6 X-ray binaries (XRBs) and 21 Ultraluminous X-ray sources (ULXs). All the six XRBs are found to be in the spectrally hard state ($Γ\sim$ 1.52-2.29) which indeed may be due to thermal COMPTONization. Only one ULX, CXOUJ032251.2-370950 (X-5), was found to be spectrally soft while the remaining 20 ULXs were spectrally hard. The spectral parameters of X-5 with an inner disk temperature (kT$_{in}$) $\sim $ 0.5 keV and an estimated bolometric luminosity, L$_X \sim$ 3.26 $\times$ 10$^{39}$ erg s$^{-1} $ requires a BLACK HOLE of mass, M$_{BH} \sim$ 137.86$^{+66.62}_{-47.41}$ M$_\odot $ accreting at $ \sim$ 0.19 times its Eddington limit. 8 ULXs, X-4, X-8, X-9, X-10, X-11, X-12, X-20 and X-21, were found to be in the Extremely luminous X-ray sources (ELXs) regime with even their lower limit of luminosity $>$ 10$^{40}$ erg s$^{-1}$. Softening/Hardening of spectra with or without changes in the luminosity were also observed in some ULXs/ELXs. In the hard ELX, X-8, spectral softening with almost consistent luminosity was observed. While in the ULXs X-20 and X-25 spectral softening with increasing luminosity was observed. However spectral hardening with increase in luminosity were observed in the ULXs X-21 and X-26.
[abstract 21 / 44] (score: 3) - Title: Emergent gravity from Michel flow with position dependent adiabatic indexAuthors: Apashanka Das, Souvik Ghose, Tapas K. Das,Comments: 12 pages, 8 figures, revtex_4.2 classSubjects: astro-ph.HE gr-qcCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
Spherically symmetric, general RELATIVISTIC Bondi accretion is known as the Michel flow. The stationary integral transonic solutions for the Michel flow has been constructed for multi-component accretion described by an equation of state where the adiabatic index varies with the radial distance along which the streamlines are studied, and the corresponding phase portrait spanned by such radial distance and the flow Mach number has been obtained. Borrowing the techniques used in the dynamical systems theory, the nature of the transonic points of the aforementioned flow has been classified. The steady state flow has been perturbed to study the stability of the stationary solutions, and it has been found that such flows are stable under the (linear) radial perturbation. As a consequence of the stability analysis, the corresponding acoustic space time embedded within the accreting matter has been obtained, and the horizon of the metric of such sonic space time has been identified by constructing the causal structure with the help of the Carter-Penrose diagrams. In this way, the accreting BLACK HOLE systems in the general RELATIVISTIC set up has been investigated from various different perspectives - from its astrophysical aspects, from the dynamical systems point of view, as well as within the realm of the classical analogue gravity phenomena.
[abstract 22 / 44] (score: 3) - Title: Atmospheric Dynamics of Asymmetrically Magnetized Hot JupiterAuthors: Miaoyin Tang, Cong Yu,Comments:Subjects: astro-ph.EPCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
We investigate the influence of asymmetric MAGNETic fields on the atmospheric circulation of hot Jupiters based on a Shallow-Water Magnetohydrodynamic (SWMHD) model. The Shallow-Water Hydrodynamic (SWHD) models predict eastward equatorial JETs and hotspot offsets, while some observations have revealed westward hotspots, suggesting that MAGNETic fields may play an important role. We incorporate asymmetric MAGNETic fields between hemispheres, and analyze their effects through linear perturbation analysis and numerical calculations. Our results indicate that strong MAGNETic fields play a dominant role in momentum transport. Asymmetric MAGNETic field configurations lead to hemispheric temperature contrasts, with the dayside temperature maxima in the hemisphere of stronger MAGNETic field located closer to the equator. With the MAGNETic field fixed in one hemisphere, the equatorial hotspots shift westward then eastward as the other hemisphere's field strengthens, exhibiting a pronounced westward offset only at moderate field strengths and weak hemispheric asymmetry. These findings highlight the significance of MAGNETic field geometry in explaining observed atmospheric dynamics and hotspot variability in hot Jupiters.
[abstract 23 / 44] (score: 3) - Title: Evidence for additional structure in the effective spin distribution hints at multiple formation pathways in GWTC-5.0Authors: Sofia Alvarez-Lopez, Jack Heinzel, Salvatore Vitale,Comments: Letter: 5 pages, 4 figures. Supplementary Material: 4 pages, 2 figuresSubjects: astro-ph.HE gr-qcCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
The distribution of the effective inspiral spin ($χ_\mathrm{eff}$) of the binary BLACK HOLEs detected by LIGO-Virgo-KAGRA can shed light on their formation pathways. We analyze the GWTC-5.0 dataset with two models-one flexible, one fully parametric-that jointly describe $χ_\mathrm{eff}$ and primary mass. We clarify that the previously-reported skewness in the $χ_\mathrm{eff}$ distribution is better understood as additional structure beyond a non-skewed Gaussian bulk centered at small $χ_\mathrm{eff}$. This additional structure extends to larger $|χ_\mathrm{eff}|$, a result previously reported using GWTC-4.0 data. We measure the asymmetry of the distribution of $χ_\mathrm{eff}$ outside the Gaussian bulk from the data. With both the parametric and the flexible analyses, we find tentative evidence for a mass-dependent excess of positive $χ_\mathrm{eff}$ over negative ones outside the Gaussian bulk. Only at $m_1 \in [46,65]\,M_\odot$ do the data require a negative $χ_\mathrm{eff}$ component outside the Gaussian bulk, with $23\text{:}1$ odds. If $χ_\mathrm{eff}$ outside the Gaussian bulk are produced by hierarchical mergers-as it has been suggested-then a fraction of those mergers may be produced in environments that can generate a surplus of binaries with positive $χ_\mathrm{eff}$, such as the disks of ACTIVE GALACTIC NUCLEi.
[abstract 24 / 44] (score: 3) - Title: Between Degeneracy and Evolution: UV-to-optical Insights into the BH$^*$ Model in Little Red DotsAuthors: Rosa M. Mérida, Marcin Sawicki, Chris J. Willott, Gaia Gaspar, Kartheik G. Iyer,Comments: 22 pages, 15 figures, 4 tables. Submitted for publication in A&ASubjects: astro-ph.GACreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
Little Red Dots (LRDs) are a heterogeneous class of objects, with several proposed scenarios for their physical nature and evolution. While these theories have been tested on individual LRDs using limited spectral features, a systematic Bayesian analysis of the LRD population incorporating the different models across a broad wavelength range is still lacking. In this study, we conduct a consistent ultraviolet (UV)-to-optical continuum fitting analysis of 66 LRDs at 2
[abstract 25 / 44] (score: 3) - Title: Secondary drift-driven instabilities in the presence of a parallel-propagating electroMAGNETic ion cyclotron wave and cold multi-component ionsAuthors: Opal Issan, Patrick Kilian, Vadim Roytershteyn, Salomon Janhunen, Gian Luca Delzanno,Comments:Subjects: physics.plasm-ph physics.space-phCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
ElectroMAGNETic ion cyclotron (EMIC) waves are commonly observed in Earth's inner MAGNETosphere, particularly during geoMAGNETic storms driven by anisotropic ring-current protons. While their role in radiation belt scattering of hot ions is well established, their interaction with the cold (less than 100 eV) plasma remains less understood. This is partly due to limited MAGNETospheric cold ion observations, as spacecraft charging can prevent cold ions from reaching onboard instruments. It is well-known that the electric field of a parallel-propagating EMIC wave can drive inter-species perpendicular POLARIZATION drifts that excite lower-hybrid secondary instabilities. In multi-component plasmas, these include the modified two-stream and the ion-ion cross-field instabilities. In this paper, we study the impact of such secondary instabilities on the parallel-propagating EMIC wave and multi-component plasma via a fully kinetic particle-in-cell simulation and linear theory. We find that the secondary waves persist even at low EMIC amplitudes, provided the cold population remains sufficiently cold. The kinetic simulation demonstrates that these secondary modes produce anisotropic heating of cold protons and singly-charged oxygen ions, primarily in the direction perpendicular to the ambient MAGNETic field and of electrons in both parallel and perpendicular directions.
[abstract 26 / 44] (score: 2) - Title: Parametric instability of Alfvén wave packetsAuthors: S. S Komissarov,Comments: Published in MNRAS. A typo in eq.8 has been found and correctedSubjects: astro-ph.SRCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
Parametric instability of Alfvén wave packets with monochromatic carrier wave in low-$β$ plasma is studied using one-dimensional MAGNETohydrodynamic simulations. The results show spatial growth of incoming perturbations as they propagate through the mother wave. For sufficiently short packets, the perturbations emerge downstream of the packet as small-amplitude reverse Alfvén waves and forward slow MAGNETosonic waves. For larger packets the perturbations reach non-linear amplitude while still inside the mother wave. In this case, a downstream section of the mother wave collapses but the remaining upstream section stays largely intact and enters the phase of very slow evolution. The length scale separating the linear and non-linear regimes, as well as determining the size of the surviving section in the non-linear regime, is set by the Alfvén crossing time of the packet, the growth rate of the parametric instability for the unmodulated carrier wave, and the amplitude of incoming perturbations. The results are discussed in connection with the physics of solar wind.
[abstract 27 / 44] (score: 2) - Title: Model-agnostic search of gravitational wave echoes in LVK dataAuthors: Di Wu, Xi-Li Zhang, Qing-Guo Huang, Jing Ren,Comments: 25 pages, 12 figures, 4 tables. Python code to reproduce figures is available at https://github.com/hermione-evans/ECHOMASE-LVK . v2: matches published versionSubjects: gr-qc astro-ph.HECreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
Gravitational wave echoes offer a unique probe of the near-horizon structure of astrophysical BLACK HOLEs, beyond the standard "BLACK HOLE spectroscopy." Theoretical waveform predictions, however, remain uncertain, motivating robust searches that avoid specific echo modeling. We present a model-agnostic search framework targeting long-lived quasinormal modes (QNMs) expected from strong interior reflection. By employing a generalized phase-marginalized likelihood that coherently combines data for each QNM across a detector network, our method enhances sensitivity to the signals. To handle real detector noise, we implement an optimized notching procedure to suppress instrumental spectral lines and refine the Bayesian parameter settings. We validate the performance of this framework using injection studies on O1 background data, demonstrating reliable signal recovery in realistic noise conditions. We then apply this method to three binary BLACK HOLE merger events with high ringdown signal-to-noise ratios (SNRs): GW150914 from O1, GW231226 from O4a, and the recently reported O4 event GW250114. No statistically significant evidence for postmerger echoes is found. Consequently, we derive 90% upper limits on the network SNR and the average initial strain amplitude of the long-lived QNMs. These results provide model-agnostic constraints on late-time echoes from LVK data, complementing existing searches for other echo signatures.
[abstract 28 / 44] (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+2 figuresSubjects: hep-ph astro-ph.CO astro-ph.HECreated: 2026-06-09; Updated: 2026-06-11; Datestamp: 2026-06-11
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 29 / 44] (score: 2) - Title: Breaking Parameter Degeneracies in a Magnetically Charged Black Hole Embedded in a Hernquist Dark-Matter Halo: A Multi-Observable AnalysisAuthors: Ali Ovgun, Reggie C. Pantig, Joel Saavedra,Comments: 40 pages, 19 figures, 10 tables, improved versionSubjects: gr-qcCreated: 2026-06-09; Updated: 2026-06-11; Datestamp: 2026-06-11
We study the degeneracy of intrinsic and environmental parameters for BH observables in a static spacetime sourced by a nonlinear MAGNETic monopole immersed in a Hernquist dark-matter halo. We explore four complementary probes; the shadow radius $R_{sh}$, eikonal quasinormal-mode frequencies $Mω_R$, weak gravitational lensing $\hatθ_\infty$, and neutrino-antineutrino annihilation $\dot{Q}/\dot{Q}_{Newt}$, and map their degeneracy contours in the $(g/\mathcal{M},α/\mathcal{M})$ plane at fixed $β/\mathcal{M}$. Different parameter combinations yield signatures nearly indistinguishable from a Schwarzschild BLACK HOLE single-observable diagnostics cannot uniquely constrain the MAGNETic charge and halo amplitude. The degeneracy contours are, however, mutually non-parallel: the slopes $dα/dg$ along constant-$R_{sh}$ and constant-$Mω_R$ contours differ by a factor $\sim 5$, so their combination breaks the remaining degeneracy and constrains both parameters simultaneously. We compute the QNMs spectra using a high-order WKB method with Padé resummation. The MAGNETic charge raises the real oscillation frequency while the halo lowers it; the cancellation is observable-dependent and does not persist across all four channels. An expansion around an asymptotically renormalized Schwarzschild background of mass $\mathcal{M}=M+α$ shows that at fixed $\mathcal{M}$ both sectors reduce $R_{sh}$ at first perturbative order. For weak lensing, $\mathcal{M}$ alone determines the leading deflection, first subleading correction depends on $\mathcal{Q}=g^2+4αβ$, separating total halo mass from halo concentration. For neutrino-pair annihilation, the MAGNETic charge suppresses the deposition rate by raising the lapse, while the halo enhances it through the reverse mechanism.
[abstract 30 / 44] (score: 2) - Title: The giant pulse population of PSR B0355+54Authors: Sergei L. Kurdubov, Dmitry A. Marshalov,Comments: Submitted to ElsevierSubjects: astro-ph.HECreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
Giant pulses are rare bright radio bursts that occur in restricted ranges of pulsar rotational phase. Here we report giant pulses from PSR B0355+54, a pulsar with spin period ~0.156 s. Using 7.97 hours of observations centred at 1.46 GHz, with 128 MHz bandwidth in each circular POLARIZATIONs, we identify 432 pulse periods containing bright pulses. The giant pulses recur in two compact longitude regions inside the radio emission window. They are narrow compared with the mean profile, with median W50=290.3 us, and reach relative peak flux density ratios up to 149.7. The early longitude group has a timing scatter of 139.7 us, or 0.00089 of a rotation. The first longitude group favours right, while the second favours left circular POLARIZATION.
[abstract 31 / 44] (score: 2) - Title: Learning the Universe at High Redshifts: Impact of Accretion Modeling on Early Black Hole GrowthAuthors: Jonathan Kho, Aklant K. Bhowmick, Rainer Weinberger, Paul Torrey, Laura Blecha, Lars Hernquist, Greg L. Bryan, Alex M. Garcia, Niusha Ahvazi, Alejandro Saravia, Boon Kiat Oh,Comments: This is a Learning the Universe publication. 19 pages, 7 figures, submitted to ApJSubjects: astro-ph.GACreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
JWST discoveries of the earliest ($z \gtrsim 9$) supermassive BLACK HOLEs (BHs, $M_\bullet \gtrsim 10^6\,\rm{M}_\odot$) challenge the BH seeding and accretion models of most cosmological simulations. In this work, we compare early BH growth arising from three different accretion prescriptions characterized by distinct scalings between the accretion rate ($\dot{M}_{\rm \bullet}$) and the BH mass ($M_{\rm \bullet}$): the commonly used Bondi-Hoyle model ($\dot{M}_{\rm \bullet}\propto M_{\rm \bullet}^2$), and two free-fall models with shallower scalings ($\dot{M}_{\rm \bullet}\propto M_{\rm \bullet}^{1/2}$ and $M_{\rm \bullet}$). Bondi accretion tends to produce stronger runaway growth than the free-fall models when using heavy ($\sim10^5\,\rm{M}_\odot$) seeds in extreme environments owing to the steeper $M_\bullet$ scaling, but its sensitivity to the local gas sound speed makes it more susceptible to suppression from temperature increases due to AGN and stellar feedback. The free-fall models tend to produce stronger growth for lower-mass seeds ($\sim10^{3-4}\,\rm{M}_\odot$) in moderate environments as they are less dependent on the BH's mass to accrete effectively, however in this regime BH growth remains negligible for all accretion models in the presence of fiducial stellar feedback. Enhancing early BH growth via many BH-BH mergers disproportionately enhances subsequent accretion-driven growth for Bondi due to the steeper $M_{\rm \bullet}$ dependence. Our simulations can thus assemble BHs with masses of $\sim10^6-10^7~M_{\odot}$ at $z\gtrsim9$, as inferred by JWST, under two circumstances: 1) abundant heavy-seed formation that drives BH-BH mergers, or 2) Bondi accretion with weak feedback.
[abstract 32 / 44] (score: 2) - Title: Systematic comparison of VMEC and HINT equilibrium calculations for finite-beta LHD plasmasAuthors: Albert Civit-Bertran, Yasuhiro Suzuki, Shimpei Futatani,Comments: 2 pages, 2 figures, Rapid communicationSubjects: physics.plasm-phCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
A systematic comparison between VMEC and HINT equilibrium calculations has been carried out for Large Helical Device plasmas to clarify the influence of the assumption of the nested flux surfaces at finite beta. Three vacuum MAGNETic-axis configurations, $R_{\rm axV} = \SI{3.53}{\, m}$, $\SI{3.60}{\, m}$, $\SI{3.85}{\, m}$, are examined for the beta values on the axis in the range $β_0 \in [0.0\%, 5.0\%]$. The MAGNETic-axis position, the rotational transform on the axis, and the plasma volume enclosed by the last closed flux surface are compared between the two codes. At low-$β_0$, VMEC and HINT give consistent equilibria, indicating that the nested flux surfaces are largely preserved. Above a configuration-dependent critical $β_0$, however, the two solutions begin to diverge, indicating that the nested flux surfaces assumption is compromised. In HINT, the enclosed plasma volume decreases at higher beta because the stochastic MAGNETic field evolves near the plasma edge, whereas VMEC cannot represent this flux surface breaking due to its assumption of nested flux surfaces. These results show that the 3D equilibrium responses in LHD equilibria become increasingly important from inward- to outward-shifted configurations, mainly through Pfirsch-Schlüter current-driven perturbations of the MAGNETic field and the resulting edge stochasticity.
[abstract 33 / 44] (score: 2) - Title: Potential detection of ~ 4.2 keV emission line from GRS 1747-312Authors: Amom Lanchenbi Chanu, Akash Garg, Ranjeev Misra, A. Senorita Devi,Comments: Accepted for publication in Journal of High Energy AstrophysicsSubjects: astro-ph.HECreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
We present a broadband spectral analysis of the neutron star LMXB GRS 1747-312 using $\sim$ 40 ks AstroSat data. The source was observed during the decay phase of the 2017 outburst, with an absorbed 1.0-5.5 keV flux of 1.67$^{+0.04}_{-0.07}\times$10$^{-11}$ erg s$^{-1}$ cm$^{-2}$, corresponding to a luminosity of $\sim$(0.9-1.80)$\times$10$^{35}$ erg s$^{-1}$. The continuum is modeled with thermal Comptonization of blackbody emission and interstellar absorption. A mildly broad iron line at $\sim$6.4 keV is fitted with a disc reflection component. Narrow lines below 2 keV are described by a hot plasma using the XSPEC model APEC. Additionally, there is a potential detection of an emission line at 4.19$^{+0.12}_{-0.10}$ keV with width $σ$ = 0.2 $\pm$ 0.2 keV and line flux of 13$^{+10}_{-9}\times$10$^{-5}$ erg s$^{-1}$ cm$^{-2}$. Examination of several short-duration ($\sim$ few kiloseconds) SWIFT observations at a few times the AstroSat source flux provided upper limits to the line flux of $<$30$\times$10$^{-5}$ erg s$^{-1}$ cm$^{-2}$. The 4.2 keV line likely originates from reflection off the neutron star surface. Shifting the neutral Fe K$_α$ line from its rest energy of 6.4 keV to 4.2 keV requires a redshift of z $\sim$ 0.6, consistent with that expected from the surface of a non-spinning 1.4 M$_\odot$, 10 km radius neutron star. If confirmed, this feature provides a potential direct measurement of gravitational redshift, allowing us to place strong constraints on the neutron star's mass-to-radius ratio and gain valuable insights into the equation of state (EOS) of dense matter.
[abstract 34 / 44] (score: 2) - Title: A phase-coherent timing solution for the X-ray dim isolated neutron star eRASSU J131716.9-402647Authors: J. Kurpas, A. M. Pires, A. D. Schwope, F. Haberl, S. Sheth,Comments: 10 pages, 6 figures, accepted for publication in A&ASubjects: astro-ph.HECreated: 2026-06-09; Updated: 2026-06-11; Datestamp: 2026-06-11
Based on its predominantly thermal X-ray emission and long spin period, the isolated neutron star eRASSU J131716.9-402647 is one of the most promising candidates for membership in the still small class of X-ray dim isolated neutron stars (XDINSs). Confirmation of this classification, however, requires a more detailed characterisation of the source's timing and spectral properties. In this work, we present new NICER observations which, together with previous X-ray follow-up, allow us to constrain the timing properties and long-term evolution of eRASSU J131716.9-402647. We obtain a coherent timing solution with a spin period of $P\sim12.8$ s and a period derivative of $\dot{P}\sim9\times 10^{-14}$ s s$^{-1}$, which best-describes the spin evolution of the source. These parameters imply a dipolar MAGNETic field strength of $3\times10^{13}$ G and a spin-down luminosity of order $10^{30}$ erg s$^{-1}$. Spectral modelling reveals no significant change in the spectral state over the 15 months of observational monitoring and indicates a thermal luminosity that likely exceeds the rotational energy loss. This suggests a thermal evolution that has been significantly influenced by past reheating. The energy dependence of the double-humped pulse profile closely resembles that observed in the XDINS RX J1308.6+2127, with the pulsed fraction increasing towards higher energies. Taken together, these results unambiguously confirm the XDINS nature of eRASSU J131716.9-402647, making it the first newly confirmed XDINS in more than two decades.
[abstract 35 / 44] (score: 2) - Title: Phase-dependent MAGNETic coherence in the turbulent interstellar mediumAuthors: Iryna S. Butsky, Caleb Redshaw, Minjie Lei, Susan E. Clark, Drummond B. Fielding,Comments: 10 pages, 6 figures. Submitted to ApJSubjects: astro-ph.GACreated: 2026-06-09; Updated: 2026-06-11; Datestamp: 2026-06-11
Magnetic fields permeate the multiphase interstellar medium (ISM), yet their phase-dependent structure remains poorly constrained by observations. Dust POLARIZATION and \ion{H}{1} emission together offer complementary probes of the plane-of-sky MAGNETic field and cold neutral medium (CNM) gas structure, respectively. Recent observational work has shown that in the diffuse ISM, the dust POLARIZATION fraction correlates positively with the CNM mass fraction ($f_{\rm CNM}$) but not with total \ion{H}{1} column density, suggesting a phase-dependent MAGNETic field geometry. Here, we use extremely high-resolution ($2048^3$) simulations of the turbulent, MAGNETized, multiphase ISM to investigate the physical origin of this trend. By constructing synthetic \ion{H}{1} and dust POLARIZATION maps, we directly compare our simulations to the observational results of \citet{Lei:2024}. We recover a positive $f_{\rm CNM}$-POLARIZATION correlation most clearly for sightlines intersecting fewer than $\sim$20 discrete CNM clouds, while the trend becomes weak or intermittent for larger cloud counts, consistent with the expectation that high-Galactic-latitude sightlines contain relatively few independent cold structures. We show that this correlation reflects genuine phase-dependent MAGNETic structure: CNM clouds tend to be elongated along the local MAGNETic field and, when normalized by column density, exhibit lower MAGNETic disorder than the warm neutral medium (WNM). We further demonstrate that apparent discrepancies between simulation- and observation-based measures of MAGNETic disorder arise from whether disorder is quantified per unit path length or per unit mass. Our results support a picture in which CNM structures host relatively ordered MAGNETic fields, producing higher POLARIZATION fractions along CNM-dominated sightlines in the diffuse ISM.
[abstract 36 / 44] (score: 2) - Title: The Light Curve of Wind-Reprocessed Tidal Disruption EventsAuthors: Brenna Mockler, David Khatami, Daniel Kasen, Xiaoshan Huang, Anthony L. Piro,Comments: accepted to ApJL; 21 pages, 9 figuresSubjects: astro-ph.HE astro-ph.GACreated: 2026-06-09; Updated: 2026-06-11; Datestamp: 2026-06-11
The source of the optical/UV emission in tidal disruption events (TDEs) remains an enduring question in the field. Connecting the observed emission to the source is critical for both our understanding of these transients and for using TDEs to study the efficiency of super-Eddington accretion and BLACK HOLE growth. To explore this connection, we ran time-dependent 1D radiation hydrodynamic simulations of TDE emission with the Sedona monte carlo radiative transfer code, focusing on the reprocessing paradigm. Our simulations follow a compact, evolving X-ray and EUV bright source and surrounding reprocessing outflow over multiple months, using luminosities and mass flow rates consistent with hydro simulations of tidal disruptions. We determine the efficiency of reprocessing as a function of time in this dramatically changing environment and reproduce key observables including timescales, luminosities, and color evolution. Notably, we see a strong wavelength-dependence in the emission timescale due to reprocessing effects. Early on there is an X-ray flare which quickly fades as material builds up and obscures the hot source. At the same time, the optical/UV luminosity begins to rise. Though the optical/UV light curve has a similar shape to the bolometric light curve, the optical peak is offset by $\sim$3 weeks from the bolometric peak due to the time required to build up the reprocessing layer. This implies that early time, high energy emission may be missed for TDEs discovered in optical surveys, and the initial disruption and mass return time to the BLACK HOLE may occur earlier than optical light curves suggest.
[abstract 37 / 44] (score: 2) - Title: Horizon absorption in eccentric precessing binary BLACK HOLE inspirals and its importance for gravitational wave data analysisAuthors: Alberto Álvaro-Díaz, Gonzalo Morras,Comments: 15 pages, 9 figuresSubjects: gr-qc astro-ph.HECreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
During the evolution of a binary BLACK HOLE, energy and angular momentum are exchanged between the orbital motion and the individual BLACK HOLEs through horizon absorption, modifying both the binary dynamics and the BLACK HOLE masses and spins. This leaves an imprint on the emitted gravitational waves that may be relevant for the accurate modeling of signals observed by current and future detectors, while also offering a probe of the nature of compact objects. In this work, we derive, for the first time and at leading order in the post-Newtonian expansion, the effect of horizon absorption in binary BLACK HOLE inspirals with both orbital eccentricity and spin-induced precession, and we incorporate these corrections into the pyEFPEHM waveform model. We then quantify their impact through analytical estimates of the orbital dephasing, waveform mismatches, and Bayesian parameter-estimation studies. The effect is largest for systems with large spin components (anti-)aligned with the orbital angular momentum ($|\vecχ_i \cdot \hat{l}| \sim 1$), highly unequal mass ratios ($q=m_2/m_1 \ll 1$), and long inspirals spanning a wide frequency range ($\log(f_\mathrm{max}/f_\mathrm{min}) \gg 1$). For such systems, neglecting horizon absorption biases the recovered binary parameters at moderate signal-to-noise ratios. In quasi-circular binaries these biases largely absorb the effect, rendering it difficult to detect. In eccentric binaries, however, the richer signal morphology breaks this degeneracy, making horizon absorption potentially measurable in high signal-to-noise-ratio events.
[abstract 38 / 44] (score: 2) - Title: Periodic orbits as probes of charged loop quantum gravity BLACK HOLEs through gravitational wavesAuthors: Abolhassan Mohammadi, Arun Kumar, Hongwei Tan, Sushant G. Ghosh,Comments: 15 pages, 11 figures, 2 tablesSubjects: gr-qcCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
Gravitational waves from extreme-mass-ratio inspirals (EMRI) provide a direct probe of the strong-field geometry of BLACK HOLEs. Motivated by this, we study the motion of test particles and the resulting gravitational wave emission in the spacetime of a charged BLACK HOLE inspired by loop quantum gravity (LQG), where the classical singularity is replaced by a smooth transition surface arising from the LQG polymerization, in which its radius is set by the LQG area gap condition. As a result, the polymerization parameter $δ_b$ is uniquely determined by the mass $M$ and charge parameter $Q$, so that all cases examined in this work contain LQG correction. By constructing the effective potential, the innermost stable circular orbit (ISCO) and the marginally bound orbit (MBO) are determined. Periodic orbits are classified using the Levin-Perez-Giz zoom-whirl taxonomy, showing how the orbit topology shapes the waveform, so that each closed trajectory is labeled by the triple integer $(z, w, v)$ and located through the rational frequency ratio $q = ω_ϕ/ω_r - 1$. Within the quadrupole approximation, the gravitational waveforms for an EMRIs are estimated, and the resulting POLARIZATIONs are obtained in the time-domain and frequency-domain. The resulting POLARIZATIONs in the time-domain exhibit a zoom-whirl morphology, with the waveform amplitude and phase dependent on the LQG parameter. The characteristic strain peaks in the millihertz band for all values of the charge parameter $Q$, and they exceed the projected sensitivities of LISA, Taiji, and TianQin, suggesting that future observations could place meaningful constraints on the LQG polymerization parameter in the strong-field regime.
[abstract 39 / 44] (score: 2) - Title: Self-Excited Dynamo Driven by Non-Rotating Laminar Thermal Convection in a Regular TetrahedronAuthors: Akira Kageyama,Comments:Subjects: physics.flu-dynCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
We propose a minimal, rotation-free model of MAGNETohydrodynamic (MHD) dynamo action driven by laminar thermal convection in a regular tetrahedral cavity. Unlike canonical planetary-dynamo settings, where flow helicity is supplied by global rotation, the present system generates robust flow helicity purely through the geometric constraints imposed by tetrahedral boundaries. Direct numerical simulations show exponential amplification of a weak seed MAGNETic field and a nonlinear saturated state in which the MAGNETic energy exceeds the kinetic energy. The convective flow organizes into a highly symmetric pattern with \(D_4\) dihedral symmetry. The dynamo-generated MAGNETic field obeys a corresponding signed \(D_4\) symmetry involving antisymmetry under \(π\)-rotations about the two horizontal axes of the tetrahedron. The tetrahedral dynamo provides a conceptually transparent setting for isolating geometry-induced helicity, MAGNETic-field amplification, and a closed induction cycle in a non-rotating laminar flow.
[abstract 40 / 44] (score: 2) - Title: Searching for cosmic vorticesAuthors: Marek Nikołajuk, Tomasz Karpiuk, Mirosław Brewczyk,Comments: 10 pages, 7 figures, 2 videosSubjects: astro-ph.HE cond-mat.quant-gasCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
Our study focuses on the strong tidal disruption of a cold helium white dwarf passing a BLACK HOLE. We model the white dwarf as a Bose-FERMI droplet and use quantum hydrodynamic equations to simulate the binary system's evolution. As the white dwarf passes through periastron, it loses a significant amount of mass. This mass falls onto the BLACK HOLE and forms an accretion disc. Quantized vortices appear in the accretion disc, manifesting as strong electroMAGNETic radiation signals that exhibit characteristic flickering patterns changing on a timescale of a few seconds. Meanwhile, the white dwarf moves away from the BLACK HOLE. As the white dwarf moves through space, vortices run along its surface. This elongates its geometry, causing it to rotate and emit gravitational waves.
[abstract 41 / 44] (score: 2) - Title: Ionization-Induced Electrostatic Hose Instability in Electron-Beam-Sustained PlasmasAuthors: Jia-Hong Chen, Yi Yu, Jian Chen, Zhi-Bin Wang,Comments:Subjects: physics.plasm-phCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
We report the discovery of a previously unrecognized electrostatic hose instability in electron-beam-sustained plasmas, driven by the coupling between the electron beam centroid and the plasma generated via the beam-impact ionization. Unlike the conventional hose instability of RELATIVISTIC beams propagating in underdense plasmas, this instability requires only ionization-capable electron beams readily produced by common emission processes and sheath acceleration, indicating broad relevance across various discharges. A linear theory is developed to predict the hosing frequency and growth rate, and particle-in-cell/Monte Carlo simulations confirm both the onset of instability and the theoretical predictions.
[abstract 42 / 44] (score: 2) - Title: Deep Learning Calibration of the Quasar X-ray/UV Luminosity Relation for Cosmological ApplicationsAuthors: Jiaze Gao, Yun Chen, Lixin Xu, Jianping Hu, Xiaoyue Cao,Comments: 10 pages, 2 figures, 4 tablesSubjects: astro-ph.COCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
Quasars can serve as standard candles through an empirical scaling relation between their ultraviolet (UV) and X-ray luminosities. As high-redshift probes, it is critical to test whether this relation evolves with redshift. In this work, we reconstruct the Hubble diagram of the Pantheon+ sample using the deep learning--based LADDER algorithm and use it as a reference to investigate the QUASAR scaling relation. Our results, which are consistent with those from Gaussian process regression and narrow-bin analyses, show that the potentially contaminated sample at $z<0.7$ differs significantly from the $z>0.7$ sample; thus, it should be further screened or excluded when QUASARs are used as cosmological probes. We find that the scaling relation exhibits a non-linear redshift dependence that cannot be accounted for by a simple linear correction, and that this behavior is a feature of the current data sample rather than a consequence of cosmological model misspecification. To use QUASARs as standardizable candles, further modeling of the scaling relation and intrinsic dispersion, or more advanced data processing techniques, is required.
[abstract 43 / 44] (score: 2) - Title: KiDS-Legacy: Joint analysis of second- and third-order cosmic shearAuthors: L. Linke, L. Porth, P. Burger, J. Harnois-Déraps, S. Heydenreich, P. Schneider, M. Asgari, M. Bilicki, C. Georgiou, C. Heymans, H. Hildebrandt, H. Hoekstra, P. Jalan, B. Joachimi, S. Joudaki, K. Kuijken, S. Li, L. Moscardini, M. Radovich, R. Reischke, B. Stölzner, A. H. Wright, Z. Yan, Y. -H. Zhang,Comments: 14 pages plus appendix, 15 figures, submitted to A&ASubjects: astro-ph.COCreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
Weak lensing by large-scale structure is a powerful cosmological probe. While most analyses rely on second-order correlations, these are primarily sensitive to the parameter combination $S_8 = σ_8 (Ω_m/0.3)^{0.5}$, limiting their ability to constrain $Ω_m$ and other cosmological parameters independently. Higher-order statistics capture non-Gaussian features of the density field and can therefore break parameter degeneracies and extract more cosmological information from weak lensing surveys. We present a joint analysis of second- and third-order cosmic shear in the final data release of the Kilo-Degree Survey (KiDS-Legacy). We combine COSEBIs (Complete Orthogonal Sets of E-/B-mode Integrals) at scales between 2' and 300' with third-order aperture mass moments at scales between 4' and 32' to perform a joint analysis of second- and third-order statistics. Compared to previous KiDS analyses, we implement several methodological advances: an intrinsic alignment model with redshift and mass dependence, a baryon correction model validated on multiple hydrodynamical simulations, and corrections for reduced shear and source clustering. Combining COSEBIs with third-order aperture mass statistics in KiDS-Legacy yields $Ω_m = 0.297^{+0.056}_{-0.040}$ and $S_8 = 0.806^{+0.025}_{-0.023}$, significantly tightening the $Ω_m$ constraints and more than doubling the figure of merit in the $Ω_m$--$S_8$ plane compared to the two-point analysis alone. The third-order measurements pass stringent internal consistency tests, are fully compatible with the KiDS-Legacy 2-point constraints, other 2+3-point lensing results and with Planck CMB measurements within $1σ$, providing no evidence for an $S_8$ tension and demonstrating the maturity of 3-point cosmic shear as a key probe for forthcoming surveys.
[abstract 44 / 44] (score: 2) - Title: Time-dependent cosmic-ray escape from wind bubbles: hard spectra formationAuthors: Lukas Merten, Sophie Aerdker, Enrico Peretti,Comments:Subjects: astro-ph.HECreated: 2026-06-10; Updated: 2026-06-11; Datestamp: 2026-06-11
Overview: Wind-driven bubbles are dynamic systems that can accelerate COSMIC RAYs, depending on their physical properties, up to very high energies. We investigate how a time-dependent description of the particle transport may impact the escaping cosmic-ray flux. Model: The wind bubble system is modeled as spherically symmetric. Cosmic rays are continuously injected at the position of the termination shock and propagate through advection and diffusion until the escape at the time-dependent position of the forward shock, which is treated as a free escape boundary. Methods: The one-dimensional spherical time-dependent transport equation is solved by transforming it into the corresponding set of stochastic differential equations, and integrated with a modified version of the open source cosmic-ray propagation framework CRPropa. Results: We find that, during the wind driven phase, the downstream escaping spectra from wind bubbles can be harder than $\sim E^{-2}$, the conventional expectation from diffusive shock acceleration. Depending on the turbulence model the initial energy spectrum can be significantly suppressed at lowest energies, which could be an observable feature to distinguish between different turbulence realizations. This effect could lead to an efficient confinement of low energy particles, potentially leading to observable implication in terms of multi-messenger radiation and cosmic-ray accumulated grammage within the bubble.
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