New papers on Black holes & gravitational waves
180 new papers on black holes & gravitational waves in the last 7 days, within Space & cosmos. These are the 50 Pipette rates most worth reading, with the main result in the authors' own words.
The best of the week
Direct imaging of sub-parsec binary SMBHs in the central galaxy of the NGC 5044 group
The 4.9, 8.4, 15.2, and 23.6 GHz VLBA images reveal two compact, flat-spectrum, and variable radio cores separated by just 0.38 parsec at the heart of the galaxy, forming the tightest directly imaged binary AGN known by an order of magnitude.
PreprintClaims a big stepFirst Pre-peak Ultraviolet Spectrum of a Tidal Disruption Event: A Fast Outflow Revealed Prior to Maximum Light in TDE2025aarm
Our HST/STIS spectrum shows strong evidence for an early-time outflow through broad near-UV (NUV) and far-UV (FUV) absorption lines blueshifted by 10,000 km s, including two new UV broad absorption features not yet identified in a TDE.
PreprintClaims a big stepA Gamma-ray Emitting Head-Tail Radio Galaxy Swimming Through the Hot Medium of the Merging Cluster Abell 3627
Here we report, for the first time, the association of ESO~0137-G007 (z=0.016), a head-tail radio galaxy located at the outskirts of the merging cluster Abell 3627, with the gamma-ray source FL16Y~J1615.56034.
PreprintClaims a big stepCombining astrometry with pulsar timing: the first joint analysis of very low frequency gravitational waves
In the absence of detection, we set the tightest constraints to date on CW strain in the pHz band, yielding a 95% upper limit of at a reference frequency of Hz.
PreprintClaims a big stepPerformance-portable GPU acceleration of the hybrid particle-in-cell code dHybridR
To address this challenge, we present a performance-portable GPU implementation of the hybrid particle-in-cell code dHybridR.
PreprintClaims a big stepA dynamic magneto-ionic environment around a long-period radio transient
Here we present full-Stokes observations of the 421-s LPT source CHIME J0630+25 and report, for the first time, extreme rotation measure (RM) variability from approximately -400 to -1630 rad m^-2.
PreprintClaims a big stepGRB 220706A: a gamma-ray burst with a month-long engine and a luminous supernova
Here, we present observations of GRB~220706A, where X-ray follow-up reveals flaring episodes that last until days after trigger.
PreprintClaims a big stepStereoscopic gravitational-wave probe: Gravitational lensing of a binary merger in active galactic nuclei
In this work, we establish a framework of transformation rules that describe both the angles in the 2 points of view, and the Doppler effect that comes from the source's motion around the lens.
PreprintFirst Experimental Evaluation of Stray Light Noise Modeling of kilometers-long Beam Tube Arms of Gravitational Wave Detectors
We present the results of the first experimental evaluation of stray light noise models for LIGO beam tube baffles.
PreprintGravitational Imprints of Dark Energy in Neutron Stars
Our study reveals that the inclusion of DE softens EoS and reduces the maximum mass compared to the pure neutron star.
PreprintDisk truncation triggers relativistic jet launching of a highly accreting supermassive black hole
These results demonstrate that, even at high accretion rates, jet launching is linked to a hot inner flow, possibly via the Blandford-Znajek process, providing evidence for a universal disk-jet connection via geometric transition.
PreprintAstroGenesis: A Domain-Specific Multi-Agent AI for Astrophysical Research
We introduce AstroGenesis (https://astrogenai.com), a domain-specific multi-agent AI framework that integrates literature retrieval, multiwavelength data access and analysis, theoretical modeling, and research ideation within a unified research environment.The current implementation focuses on blazar research, with specialized agents coordinated by a Supervisor Agent and Planner/Replanner architecture.
PreprintSemi-Analytic Solutions For Warped, Super-Eddington Accretion Disks with Outflows
In this work, we develop a first-principles semi-analytic model of a radiation-pressure-dominated, warped accretion disk, starting from the coupled conservation equations for mass, energy, and angular momentum.
PreprintNonlinearly Causal General-Relativistic Two-Fluid Dissipative Magnetohydrodynamics
We present a formulation of general-relativistic (GR) 19-moment dissipative magnetohydrodynamics (MHD), capable of handling all first-order dissipative terms (viscosity, heat conductivity, resistivity and Hall terms), as well as all ideal electron degrees of freedom (number density, momentum and energy) in a GR astrophysical two-fluid plasma.
PreprintConstraining the Quadratic-mode Amplitude Coupling in GW250114
The inferred coefficient is consistent with predictions from numerical relativity fits and second-order perturbation theory; no comparison shows a deviation exceeding .
PreprintEnergy Partition in Relativistic Electron-Positron-Ion Reconnection
Writing for the magnetic energy available per particle in units of and , the mean lepton energy scales as , whereas the mean ion energy scales as when ions escape non-relativistically from the electric-dominated regions and approaches the lepton energy when their escape is ultrarelativistic.
PreprintAccurate Black Hole Quasinormal Modes, Regge Poles, and Greybody Factors from Light Ring Ladder Symmetry
In this regime, we uncover a hidden ladder symmetry in the perturbation equations, which maps the calculation of quasinormal modes, Regge poles, and greybody factors for a spherically symmetric black hole onto the quantum-mechanical problem of an anharmonic oscillator.
PreprintEP260119a: A High-Redshift Gamma-Ray Quiet Fast X-ray Transient Probing a Potentially Hidden Population of Relativistic Explosions
Occupying the extreme high- end of the growing Einstein Probe FXT sample, EP260119a supports the possibility that soft X-ray surveys are uncovering relativistic transients that remain undetected by current gamma-ray instruments.
PreprintA Census of Stellar-mass Black Holes in the Milky Way with POPKIN. I. Isolated Black Holes
We present POPKIN, a Python framework that couples single- and binary-star evolution with Galactic orbital dynamics to trace black-hole progenitors from the zero-age main sequence to the present-day isolated black-hole (IBH) population.
PreprintA mechanism for fast radio bursts and their narrow spectra
We find an emission mechanism for fast radio bursts (FRBs) capable of producing broad and narrow spectra.
PreprintA Coherent Search for New Galactic Magnetars using Fermi/GBM and follow-up Swift/BAT: 7 Candidates and a Large Burst Catalog
We identify seven candidate new magnetars through three complementary discovery channels.
PreprintSelf-Similar Mass Spectra of Hierarchical Black Hole Mergers
The framework yields closed scaling laws, an exactly solvable benchmark, and a classification of merger environments by a single exponent measuring how strongly mergers favor or suppress massive participants.
PreprintThe AGN Channel in 3D: Scattering Belts and the Importance of Eccentricity in the Black Hole Population
We present three-dimensional hybrid -body simulations of a population of black holes (BHs) surrounding an AGN using a new code in development, AGNBI, where close interactions are directly simulated for both single and binary objects.
PreprintMulti-messenger and multi-band signal from first-order phase transitions in proto-neutron stars
Using a constrained ensemble of model-agnostic equations of state, we follow the accretion-driven evolution of proto-neutron stars through the PT and compute the resulting multi-band GW signal.
PreprintImportance of the Resonant Cosmic-Ray Streaming Instability Upstream of Collisionless Shocks
Solving the dispersion relation for both cold and finite-spread CR distributions, we show that for the maximum-energy escaping population, the resonant mode can outgrow the non-resonant mode.
PreprintA Magnetic Unification of Merging Supermassive Black Hole Binaries
Our results unify the EM signatures of the merger of embedded coplanar SMBHBs, and provide novel observational constraints on their intrinsic magnetization.
PreprintDense Dump Codec: Error-Controlled, Random-Access Compression of GRMHD Time Series for Slow-Light Radiative Transfer
We present the Dense Dump Codec (DDC), a compression method for dense GRMHD time series.
PreprintCompact Object Mergers and Micro-Tidal Disruption Events: A Multi-Messenger Probe of Dense Stellar Environments
Simulating clusters across ten model variations and two formation histories, we find a BH-BH merger-rate density peaking at - at several tens , consistent with the local LVK rate, while the cumulative number of TDEs exceeds that of mergers by a factor of a few.
PreprintIXPE observation of the new magnetar source EP J223759.5+531421
We report on the detection of polarized X-ray emission from the new Galactic magnetar EP J223759.5+531421, discovered by the Einstein Probe Wide-field X-ray Telescope on 2026 June 28.
PreprintConvolutional Neural Network for Extraction of Photon Ring of Black Holes
We present a convolutional neural network (CNN) capable of extracting the subring from composite images containing and subrings.
PreprintA Tentative Line-like GeV Excess in Fermi Blazar 4FGL J1754.2+3212: Implications for Jet Physics and Beyond
We report the detection of a tentative, narrow spectral feature in the GeV gamma-ray spectrum of the blazar 4FGL J1754.23212, using approximately 16.5 years of observations from the Fermi Large Area Telescope.
PreprintDynamically Stable Magnetic Fields in Relativistic Neutron Stars: A Diverse Landscape of GRMHD Equilibria
Our findings demonstrate that there is memory of the magnetic-field initial conditions, and that there is no unique dynamically stable magnetic-field geometry for neutron stars.
PreprintFeeding the Void: Co-evolution of the SIDM-seeded Black Hole and the dark halo after core-collapse
We find that the BH mass reaches of the total halo mass within Gyr post-collapse.
PreprintBold claims, read criticallyA Closed-Form Master Solution for Gravitational Decoupling of a Unified Family of Isotropic Stellar Seeds
The key result is a single closure of the MGD -sector, through one source function , that integrates the decoupler equation in closed form, in terms of the Gauss hypergeometric function , for arbitrary : the anisotropic extension of the family is thus obtained from one master formula.
PreprintA Multi-Mission Detection Framework for High-Energy Transients: Application to a 13-year Fermi/GBM and Swift/BAT Sample
We find that, under optimal conditions, a two-mission search can increase the accessible volume for short gamma-ray bursts by up to .
PreprintFast Radio Bursts Associated with Persistent Radio Sources Prefer Hydrogen-poor Superluminous Supernova Host Environments
These results suggest that FRB-PRSs do not simply trace star formation activity or the general FRB host population, but instead favor SLSN-I-like environments.
PreprintProbing the Metallicity Dependence of Fast Radio Burst Progenitors with CHIME/FRB Outrigger Dwarf Host Galaxies
We measure their gas-phase metallicities and, when combined with hosts from the literature, finding that repeating and non-repeating FRBs have statistically distinct metallicity distributions.
PreprintShock-free super-Eddington accretion onto magnetized neutron star
We construct a semi-analytical hydrodynamical solution for a fully subsonic, radiation-supported magnetospheric flow in the low-Mach-number limit.
PreprintEstimating redshift distributions of Fermi blazars with multiple machine-learning models
We provide predicted redshift distributions with quantified uncertainties for 1,590 blazars without measured redshifts, offering improved support for population and evolutionary studies.
PreprintGravity-Informed Neural Networks for Post-Newtonian Binary Dynamics
We introduce a gravity-informed neural-network (GravINNs) framework for learning post-Newtonian binary orbital dynamics.
PreprintCode availablePANGU I: A Parthenon-Based Framework for Fixed-Spacetime GRMHD
To unify them, we introduce PANGU--Parthenon-Based Astrophysics for Numerical Relativity and GRMHD in a Unified Framework--a modular computational framework that integrates a shared solver across physical regimes, flexible spacetime geometry, and extensible computational infrastructure within a single architecture.
PreprintLoTSS of dual AGN: enhanced detectability and prospects for a systematic search
For the 92 objects sample, the LoTSS detection rate is ~24%, significantly higher than for matched single AGN (~9-10%), suggesting an enhanced detectability of DAGN in the LoTSS.
PreprintQuadratic Gravitational-Wave Scattering by Kerr Black Holes
We use numerical relativity to study the quadratic response of Kerr black holes to nearly monochromatic incident gravitational waves, measuring the complex self-coupling to the outgoing daughter at twice the parent frequency for black-hole spins up to .
PreprintComposition-dependent acceleration of UHE Cosmic Rays in AGN electric fields
Within the scenarios tested, the results favour a relatively proton-poor accelerated population and show that the shower-width evolution can constrain the stochastic structure of electric-field acceleration in nearby AGN.
PreprintTime-frequency analysis for LISA: Fast waveform templates
A family of fast template-generation algorithms is described for three important source classes: galactic binaries, massive black-hole binaries, and extreme mass-ratio inspirals (EMRIs).
PreprintStellar Collisions from Self-consistent Stellar Dynamics Around Growing Supermassive black Holes
Our results highlight a crucial synergy between stellar dynamics and MBH growth, identifying massive galaxies as prime targets for observing transients from destructive stellar collisions.
PreprintJet variability in small mass ratio supermassive black hole binaries
Together, these results connect cavity dynamics to large-scale jet variability and predict a set of correlated jet signatures whose relative timing and causal ordering may provide stronger evidence for a small-mass-ratio supermassive black hole binary than any one feature alone.
PreprintLittle Red Dots As Super-Eddington Fountain Flows
We argue that LRDs are super-Eddington SMBHs viewed off-axis and engulfed in a slow wind that covers most sight-lines; the fast wind escapes near the poles.
PreprintLearning Inspiral-Merger-Ringdown Waveforms from a Post-Newtonian Baseline
Our results demonstrate a machine learning driven waveform modeling strategy in which numerical relativity augments, rather than replaces, analytically known waveform structure.
PreprintEinstein Probe discovery of the magnetar EP J223759.5+531421
We report the discovery and early outburst evolution of the new Galactic magnetar EP J223759.5+531421, detected by the Einstein Probe Wide-field X-ray Telescope on 2026 June 28.
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