Current date: 2026-06-30
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Scoring abstracts
Number of records retrieved: 183
Keyword score statistics
score 7 -- 1 abstracts
score 6 -- 2 abstracts
score 5 -- 2 abstracts
score 4 -- 2 abstracts
score 3 -- 3 abstracts
score 2 -- 8 abstracts
in total -- 18 abstracts
Articles that appeared on 2026-06-30
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[abstract 1 / 18] Wow! (score: 7)
- Title: Testing the Correlations between X-ray Spectral Properties and Polarization for High Synchrotron Peaked BlazarsAuthors: M. Lynne Saade, Steven Ehlert, Ioannis Liodakis, Philip Kaaret, Fabrizio Tavecchio, Sara Capecchiacci, Riccardo Middei,Comments: Revised, submitted to MNRASSubjects: astro-ph.HECreated: 2026-06-26; Updated: 2026-06-30; Datestamp: 2026-06-30
IXPE has enabled the X-ray POLARIZATIONs of many BLAZARs to be measured. We perform the first population study for high SYNCHROTRON peaked BLAZARs observed using IXPE using a uniform X-ray data analysis. We find a potential statistically significant correlation between the X-ray spectral curvature and the X-ray POLARIZATION degree. More data is needed to determine whether this correlation is robust. The lack of any other correlations may imply that there is little connection between the energy distribution of the X-ray emitting electrons and the uniformity of the MAGNETic field in the X-ray emitting regions of these BLAZARs. These results will inform future theoretical work and potentially help narrow down the acceleration process of the SYNCHROTRON electrons.
[abstract 2 / 18] Yes (score: 6) - Title: Dual AGN and Multiple SMBH Systems in the Era of SKAOAuthors: Q. D'Amato, L. Cui, R. Deane, S. Komossa, C. Pillay, A. Tripathi, P. Kharb, H. Guo, S. Nandi, K. Rubinur, S. Anton, T. An, S. Bonoli, N. Chang, R. Dave, A. De Rosa, M. Habouzit, F. Mannucci, I. Prandoni, P. Severgnini, M. Scialpi, C. Spingola, C. Vignali, W. Xu, X. Yan, Y. Zhang,Comments: Published in Advancing Astrophysics with the SKA II (AASKAII), 2026 (arXiv:2606.20366). Report-No: AASKAII/DAmato01. Advancing Astrophysics with the SKA II (AASKAII) outlines the transformative scientific advances that will be enabled by the SKA telescopesSubjects: astro-ph.HE astro-ph.GACreated: 2026-06-26; Updated: 2026-06-30; Datestamp: 2026-06-30
We present a radio-oriented review of current strategies for the detection and characterization of dual ACTIVE GALACTIC NUCLEi (DAGN) and supermassive BLACK HOLE binaries (SMBHBs), emphasizing the crucial role of radio interferometry in advancing this field. We discuss how high-resolution radio imaging - particularly through very long baseline interferometry (VLBI) - provides a unique, dust-unbiased tool to identify multiple accreting SMBHs, disentangle AGN-related emission from STAR FORMATION, and trace components from tens of kpc to sub-parsec scales. We summarize current observational limitations, such as insufficient sensitivity-resolution combination and area coverage. We then outline how the SKAO will overcome these constraints through its unprecedented combination of sensitivity, survey speed, imaging fidelity and angular resolution, enabling the discovery and characterization of dual and binary SMBHs from the nearby Universe to the epoch of reionization. Several science cases are presented, including radio follow-ups of optical/infrared-selected DAGN, direct blind radio selection of DAGN, studies of compact bound SMBHBs, and the link between SMBHB orbital evolution and low-frequency gravitational wave emission. We further emphasize the synergy between SKAO observations and modern and upcoming facilities such as the James Webb and Euclid space telescopes, Rubin Observatory, and gravitational wave detectors including the Laser Interferometer Space Antenna and pulsar timing arrays. These combined capabilities will allow SKAO to enable the first comprehensive radio census of dual and binary SMBH systems, bridge the gap between electroMAGNETic and gravitational wave observations, and provide a statistically significant view of SMBH pairing, accretion, and merger-driven feedback throughout cosmic history.
[abstract 3 / 18] Yes (score: 6) - Title: Identifying Observational Signatures of Flux Eruption Events in Supermassive Black Hole Accretion Flows with Machine LearningAuthors: Angelo Ricarte, Erandi Chavez, Franc O, Pavlos Protopapas,Comments: Submitted to ApJ, 18 pages, 11 figures, 4 tablesSubjects: astro-ph.HECreated: 2026-06-26; Updated: 2026-06-30; Datestamp: 2026-06-30
Simulated BLACK HOLE accretion flows with strong MAGNETic fields often exhibit "flux eruption events" (FEEs), transient and localized expulsions of matter near the event horizon due to MAGNETic RECONNECTion. It may now be possible to image them with the Event Horizon Telescope (EHT), a global network of millimeter-wave observatories that images BLACK HOLEs. Here we use machine learning as an interpretable inference tool to identify observational signatures of FEEs that could be accessible to the EHT. First, we train a convolutional neural network to learn task-relevant representations of FEEs in uncorrupted simulated images. After using this network to label a larger set of images, we then train interpretable models (random forest and logistic regression) to determine observational signatures. We find that during a FEE, images in the millimeter tend toward more diffuse emission, higher linear POLARIZATION, and lower total fluxes, but these signatures are weak for most FEEs compared to the usual time variability of these features. Moreover, the Q-U loop rotation rate decreases during FEEs, contrary to a picture in which FEEs could jointly cause both millimeter Q-U loops and flares. Our random forest trained on observable summary statistics achieves ~80% class-weighted accuracy, suggesting that the CNN learns FEE structure not fully mapped onto these traditional summary statistics. Our results imply that image size and POLARIZATION fraction can be used to flag candidate FEEs, but high-resolution, high-dynamic range images will still be important to confirm FEEs and test accretion flows for this phenomenon.
[abstract 4 / 18] Yes (score: 5) - Title: EP260321a/SN 2026gzf: The Faintest Shock Breakout Associated with a Broad-Lined SupernovaAuthors: Brendan O'Connor, Xander J. Hall, Malte Busmann, Daniel Gruen, Alberto Floris, Tomas Cabrera, Ziyuan Zhu, Antonella Palmese, Dylan Green, John Banovetz, Julius Gassert, Christopher L. Fryer, Roberto Ricci, Eleonora Troja, Surya Shivaprasad, Gregory R. Zeimann, Ariel J. Amsellem, Stephen Bailey, Segev BenZvi, Simone Dichiara, Hendrik van Eerten, Jeremy Hare, Lei Hu, Christopher M. Irwin, Keerthi Kunnumkai, Konstantin Malanchev, Mitra Maleki, Michael J. Moss, Adam D. Myers, Dheeraj Pasham, Christoph Ries, Geoffrey Ryan, David Schlegel, Michael Schmidt, Silona Wilke, Yu-Han Yang,Comments: Accepted for publication in ApJL on June 26, 2026Subjects: astro-ph.HECreated: 2026-06-26; Updated: 2026-06-30; Datestamp: 2026-06-30
The explosion of a star is first marked by the shock wave breaking out of the stellar surface, producing a burst of ultraviolet and X-ray radiation. These events are observationally rare, despite likely accompanying the majority of SUPERNOVAe. Here, we report on our multi-wavelength observing campaign of the closest Einstein Probe fast X-ray transient EP260321a at $z=0.0344$. The thermal ($kT=130$ eV) X-ray emission with peak luminosity $1.0\times10^{45}$ erg s$^{-1}$ points to a shock breakout origin. We demonstrate that EP260321a is accompanied by a broad-lined Type Ic SUPERNOVA, SN 2026gzf. The SUPERNOVA properties, including its spectral evolution, lightcurve evolution, and expansion velocities, are all typical of the energetic stripped-envelope SUPERNOVAe associated with GAMMA-RAY BURSTs. However, deep X-ray upper limits obtained with the \textit{Chandra X-ray Observatory} do not detect an X-ray afterglow, and instead exclude the afterglow of known GAMMA-RAY BURSTs or fast X-ray transients. If the stellar explosion launched a successful RELATIVISTIC JET, we require that it had both a low Lorentz factor $Γ_0$\,$<$\,$30$ and a kinetic energy $E_\textrm{kin}$\,$<$\,$10^{49}$ erg for a stellar wind density of $A_*$\,$\gtrsim$\,$1$. We propose that EP260321a originated from a mildly RELATIVISTIC, weak outflow that was choked by the progenitor star. This scenario is capable of naturally explaining its low X-ray luminosity and lack of prompt gamma-ray emission. EP260321a bridges the gap between SN 2008D and low-luminosity GRBs, suggesting a greater diversity in the physical parameters of stripped stars as they undergo terminal collapse.
[abstract 5 / 18] Yes (score: 5) - Title: Stochastic Variability of Binary AccretionAuthors: Akhil Nair, Jonathan Zrake,Comments: 15 pages, 9 figuresSubjects: astro-ph.HE astro-ph.GACreated: 2026-06-26; Updated: 2026-06-30; Datestamp: 2026-06-30
We measure the power spectral density (PSD) of the accretion rate time series in an unequal mass (q = 0.2) binary surrounded by a circumbinary gas disk, using very high-resolution 2D hydrodynamics simulations. Our aim is to identify new signposts of supermassive BLACK HOLE (SMBH) binaries in ACTIVE GALACTIC NUCLEi (AGN), based on the shape of the continuum PSD, to complement well-studied line features in the PSD (periodicities). We find that the continuum PSD is a broken power-law, transitioning from flat (white noise) to a slope of -4 at a break frequency generically ~5 times the binary orbital frequency. This form is expected when (a) delivery of gas from the circumbinary disk to the individual "minidisks" is a damped random walk with correlation time equal to binary orbital period and (b) the minidisks function as low-pass filters acting at the Kepler frequency of the outer edge of the smaller BLACK HOLE's minidisk; we show numerical evidence for both. The broken power-law PSD is attained in a limit where the secondary BLACK HOLE is much smaller than its minidisk, realized numerically by a sufficiently small "sink" region; larger sinks lead to excess high-frequency noise seen as accretion rate spikes, and we argue these should be regarded as artificial when the BLACK HOLEs themselves are smaller than the sink regions. The broken power-law PSD is reminiscent of stochastic variability in ordinary AGN, inviting the conjecture that canonical AGN variability could result from widespread binarity, however pulsar timing experiments may exclude this possibility.
[abstract 6 / 18] Yes (score: 4) - Title: Mass Transfer in Tidally Heated Stars Orbiting Massive Black Holes and Implications for Repeating Nuclear TransientsAuthors: Philippe Z. Yao, Eliot Quataert,Comments: 12 pages, 6 figures, Published in the Open Journal of AstrophysicsSubjects: astro-ph.HE astro-ph.GA astro-ph.SRCreated: 2026-06-24; Updated: 2026-06-30; Datestamp: 2026-06-30
The structure of stars orbiting close to supermassive BLACK HOLEs (SMBHs) can be dramatically modified by tidal heating, which can in principle dissipate an energy much larger than the stellar binding energy. We use analytic models and MESA to explore the coupled dynamics of tidal heating, stellar structural evolution, orbital decay due to gravitational waves and tides, and mass transfer. In contrast to more equal mass stellar binaries, the stable mass transfer rate for stars orbiting SMBHs is typically set by the tidal heating timescale (the timescale for tides to increase the stellar radius), not by the gravitational wave orbital decay timescale. The resulting stable mass transfer rate is sensitive to the tidal heating model but is plausibly $\sim 10^{-5}-10^{-3} M_\odot {\, \rm yr^{-1}}$ (and perhaps larger), sufficient to produce low-luminosity ACTIVE GALACTIC NUCLEi in many galaxies. The stability of mass transfer is sensitive to where in the stellar interior the tidal energy is dissipated. MESA models confirm the expected result that mass transfer is unstable (stable) if tidal heating increases (decreases) the fraction of the star that is convective. More detailed conclusions about the stability of mass-transfer will require self-consistently calculating how the tidal heating of stars changes in response to internal structural changes produced by the tidal heating itself. Stars with tidal heating-induced mass transfer can produce a large population of low-luminosity ACTIVE GALACTIC NUCLEi; they may also be the progenitors of some partial tidal disruption candidates (e.g., ASASSN-14ko) as well as short-period quasi-periodic eruptions (e.g., eRO-QPE2 and GSN 069). However, many repeating nuclear transients produced by tidal heating-induced mass loss are likely fainter than those detected thus far, and remain to be discovered.
[abstract 7 / 18] Yes (score: 4) - Title: VLBI-Enabled Localization of Continuous GW SourcesAuthors: Keitaro Takahashi, Takuya Akahori, Kenta Fujisawa, Hiroshi Imai, Hajime Kita, Hideyuki Kobayashi, Hiroaki Misawa, Kotaro Niinuma, Tomoaki Oyama, Kazuhiro Takefuji, Fuminori Tsuchiya,Comments: Published in Advancing Astrophysics with the SKA II (AASKAII), 2026 (arXiv:2606.20366). Report-no:AASKAII/Takahashi01. Advancing Astrophysics with the SKA II (AASKAII) outlines the transformative scientific advances that will be enabled by the SKA telescopesSubjects: astro-ph.IM astro-ph.HECreated: 2026-06-27; Updated: 2026-06-30; Datestamp: 2026-06-30
Pulsar timing arrays (PTAs) are opening the nanohertz gravitational-wave (GW) band by timing millisecond pulsars (MSPs) to target signals from supermassive BLACK HOLE binaries (SMBHBs). Beyond evidence for a stochastic background, a central SKA-era objective is detecting individual continuous-wave (CW) sources. The scientific payoff hinges on localization: conventional PTA searches yield uncertainties of tens-hundreds of deg$^2$, too large to identify a unique host, obtain a redshift, infer intrinsic masses, or pursue electroMAGNETic counterparts. This limitation is chiefly geometric: the CW response includes Earth and pulsar terms, and poorly known pulsar distances make the pulsar-term phase a free parameter that degrades triangulation. If distances to a few MSPs are known to better than a GW wavelength ($\sim$ 1 pc), these phases are fixed and localization improves by orders of magnitude. Simulations indicate that with sub-parsec distances for a handful of nearby MSPs, the uncertainty can shrink to $\sim 10^{-3}$ deg$^2$ (arcminute scale), enabling unique host association and multi-messenger follow-up. Achieving such distances requires $\sim$ 10 $μ$arcsec parallaxes for MSPs within a few hundred parsecs, a precision now approached with Very Long Baseline Interferometry (VLBI) and expected to become practical with phased-array SKA1-Mid operating as a sensitive VLBI element. SKA1's multi-beam, multi-calibrator astrometry will provide the independent distance priors needed for PTAs to localize nanohertz GW sources and measure SMBHB parameters and environments. We assess VLBI's role in PTA CW searches and propose a concrete SKA1-Mid observing strategy for nearby MSPs to deliver the required sub-parsec distances.
[abstract 8 / 18] (score: 3) - Title: Electron penetration heating in turbulent MAGNETic loops driven by nonRELATIVISTIC LASER-plasma interactionAuthors: Zheng Gong, Sida Cao, Caleb Redshaw, Matthew R. Edwards,Comments:Subjects: physics.plasm-ph astro-ph.HECreated: 2026-06-27; Updated: 2026-06-30; Datestamp: 2026-06-30
Using particle-in-cell simulations to study nonRELATIVISTIC LASER pulse propagation in a under-critical plasma, we identify a novel mechanism that occurs during the growth of turbulent MAGNETic loops: electron penetration heating. The loops have an electroMAGNETic left-hand chirality distinct from that of well-known quasistatic MAGNETic islands. The fast electrons penetrate through the loops and thus are accelerated to unexpected RELATIVISTIC energies due to the symmetry breaking induced by the coupling between the loop field and the non-RELATIVISTIC electroMAGNETic wave. The identified features of penetration heating and MAGNETic loops might provide an alternative perspective for understanding superponderomotive electron heating in under-critical plasmas irradiated by nonRELATIVISTIC LASER pulses. This is a potential explanation for anomalous hot electron generation in scenarios of LASER-driven inertial confinement fusion.
[abstract 9 / 18] (score: 3) - Title: Pulsational mass loss from supermassive stars creates the compact shells of Little Red DotsAuthors: Devesh Nandal, Igor Chilingarian, Chris Nagele, John Chisholm, Franz E. Bauer, Abraham Loeb,Comments: 20 pages, 6 figures. Accepted by ApJL !Subjects: astro-ph.HE astro-ph.GA astro-ph.SRCreated: 2026-06-27; Updated: 2026-06-30; Datestamp: 2026-06-30
Little Red Dots (LRDs) have emerged as one of the central puzzles of the JWST era. Their spectra increasingly require dense gas close to the source, yet the physical origin of that cocoon-like structure remains unclear. We examine whether late pulsational mass loss from supermassive stars (SMS)leads to dense gas cocoons. We analyze five accreting GENEC models at different metallicities with characteristic masses of order $10^5\,M_\odot$, following them through post-accretion evolution with radial pulsation calculations and general RELATIVISTIC (GR) stability diagnostics. Mass loss during the final stages of evolution occurs not as a steady wind, but through discrete strange-mode ejection episodes. In the $Z=10^{-2}\,Z_\odot$ model, which provides the clearest LRD analogue, four late episodes last $41$--$282$ yr and eject $10$--$348\,M_\odot$ each, for a total loss of $(4.8-10)\times10^2\,M_\odot$; the final episode alone contributes $\simeq 73\%$ of that budget. Since the last episode dominates the mass-loss, it is the only event sufficiently massive enough to leave behind a compact, optically thick shell extending out to 0.4 pc that reproduces the LRD dense gas cocoon. The final ejecta are H/He dominated but chemically distinctive, with a robust nitrogen-rich composition, $\log(\mathrm{N/O})\simeq0.13$ and $\log(\mathrm{C/O})\simeq-0.23$. The SMS reaches GR instability at an age of $\sim 1$ Myr and collapses in $\sim10^4$ s, retaining $\sim 99\%$ all of its mass. Across the full metallicity range from Pop III to $10^{-2}\,Z_\odot$, this shell-ejection channel persists. Pulsational mass-loss from SMSs therefore provides a physically motivated origin for the compact cocoon-like structure implied by LRDs, while remaining the natural progenitors of the massive BLACK HOLE seeds invoked in direct collapse scenario.
[abstract 10 / 18] (score: 3) - Title: Semi-Implicit Stellarator Magnetohydrodynamics with Nodal Spectral ElementsAuthors: C. R. Sovinec, S. A. Patil, J. V. Cauilan,Comments:Subjects: physics.plasm-ph physics.comp-phCreated: 2026-06-26; Updated: 2026-06-30; Datestamp: 2026-06-30
Nonlinear time-dependent computation of macroscale dynamics in stellarators is motivated by laboratory results showing the possibility of robust operation in conditions where MAGNETohydrodynamic (MHD) modes are linearly unstable. A new formulation of semi-implicit MHD computation for toroidally shaped MAGNETic confinement systems uses 2D nodal spectral elements over the poloidal plane and Fourier representation over a generalized toroidal angle. Geometric mappings and steady-state (equilibrium) fields are expanded in the same 3D representation as the time-evolved fields to model non-axisymmetric configurations. For accuracy at large timestep, the semi-implicit operator is based on the ideal-MHD energy integral using 3D pressure and MAGNETic fields. The nodal spectral elements allow numerical convergence through either h-refinement or p- refinement. Our implementation (NIMSTELL) with the continuous H1 expansion of MAGNETic-field components and diUusive divergence control is a generalization of the NIMROD code [JCOMP 195, 355]. The NIMSTELL implementation is verified linearly and nonlinearly on resonant ideal interchange, where convergence from the stable side results from the stabilization method used in NIMROD [JCOMP 319, 61]. Optionally, NIMSTELL may use an H(curl) representation for vector potential, and both MAGNETic representations are verified with respect to results from JOREK [Phys. Plasmas 29, 063901] on linear and nonlinear MAGNETic tearing in the W7-A rotating-ellipse configuration. Application of the existing vector-potential implementation to interchange shows that it needs a minimum level of electrical resistivity to avoid numerical noise for a given level of spatial resolution. Solving the algebraic systems from the implicit parts of the time advance is facilitated by including the Fourier components of stellarator mode families in each preconditioning operation.
[abstract 11 / 18] (score: 2) - Title: A positivity preserving and entropy stable nodal discontinuous Galerkin scheme for ideal MHDAuthors: Yue Wu, Chi-Wang Shu,Comments: 24 pages, 8 figuresSubjects: math.NA cs.NA physics.comp-phCreated: 2026-06-27; Updated: 2026-06-30; Datestamp: 2026-06-30
Numerically solving MAGNETohydrodynamic (MHD) equations faces many challenges: avoiding divergence error, maintaining positivity, and satisfying entropy conditions. Among discontinuous Galerkin (DG) schemes, there has been a modal version that is locally divergence-free and positivity preserving and a nodal version that is semi-discretely entropy stable. In this work, we develop a DG scheme that combines the advantages of these two and solves all the three challenges. The key ingredients that bring these two schemes together are an HLL numerical flux with entropy stable signal speed estimates and a locally divergence-free projection. To handle problems with strong shocks, the essentially oscillation-free damping is applied. Various numerical experiments verify the accuracy and robustness of our method.
[abstract 12 / 18] (score: 2) - Title: $Ab$ $initio$ modeling of Galactic dust polarized CMB foregroundAuthors: Alexei G. Kritsuk, Ka Wai Ho, Ka Ho Yuen, Raphael Flauger,Comments: 4 pages, 3 figures, contribution to the 2026 Cosmology session of the 60th Rencontres de MoriondSubjects: astro-ph.GA astro-ph.COCreated: 2026-06-26; Updated: 2026-06-30; Datestamp: 2026-06-30
We present the analysis of high-resolution synthetic dust POLARIZATION maps derived from large-scale simulations of MAGNETized multiphase interstellar turbulence carried out with the AthenaK code on the $Frontier$ exascale supercomputer at the Oak Ridge National Laboratory. Our turbulence model accurately captures spectral properties of the $E$- and $B$-modes measured by $Planck$ at 353 GHz. The simulations provide new insights into the physical origins of the observed $E/B$ asymmetry and positive $TE$ signal, facilitating the development of advanced models of Galactic foreground emission for current and future CMB experiments.
[abstract 13 / 18] (score: 2) - Title: Dynamical Casimir Effect and Vacuum Friction in the Near-Horizon Geometry of a Black HoleAuthors: Hamed Hadi, Amin Rezaei Akbarieh, Goksel Daylan Esmer,Comments: 12 pagesSubjects: gr-qcCreated: 2026-06-26; Updated: 2026-06-30; Datestamp: 2026-06-30
We investigate the Dynamical Casimir Effect (DCE) for a RELATIVISTIC scalar field confined within a cavity possessing moving boundaries in the (1+1)-dimensional near-horizon geometry of a BLACK HOLE. By applying a coordinate transformation, we map the moving-boundary problem to an equivalent acoustic metric with static boundaries, allowing for an exact canonical Hamiltonian formulation. We find that the local gravitational redshift fundamentally alters the vacuum structure, and the dynamical boundary motion induces time-dependent mode-mixing. When a boundary moves, it scatters the fluctuations of the ambient Hartle-Hawking state, generating a flux of created particles. Crucially, because the coordinate speed of light relative to the Killing time $t$ vanishes as one approaches the event horizon, we establish that maintaining physical, subluminal boundary motion requires the mechanical oscillation amplitude to scale proportionally with the proper distance to the horizon. Consequently, the effective Mach number of the moving mirror approaches zero in the near-horizon limit. Using a rigorous small-amplitude perturbative expansion and proper canonical operator normalization, we demonstrate that the transition probability into the field is heavily suppressed by a conformal geometric factor. Furthermore, we account for the Bose-enhancement caused by the thermal Hawking bath. While the thermal presence introduces infrared density-of-states enhancement, it remains insufficient to overcome the kinematic damping. Finally, we conclude that the extreme spacetime curvature acts to protect the near-horizon vacuum; the transition probability vanishes as the boundary approaches the event horizon, indicating a geometric and kinematic suppression of particle creation in the strong-gravity limit.
[abstract 14 / 18] (score: 2) - Title: Twin Peaks: Resolving Features in the Binary Black Hole Mass Function with COSMIC-METISSEAuthors: Duncan B. Maclean, Poojan Agrawal, Katelyn Breivik, and Alexandra G. Guerrero, Michael Zevin, Mathieu Renzo, Carl L. Rodriguez,Comments: 22 pages, 12 figures. Submitted to ApJSubjects: astro-ph.HECreated: 2026-06-26; Updated: 2026-06-30; Datestamp: 2026-06-30
Gravitational waves from inspiraling binary BLACK HOLEs (BBHs) provide insights into the lives and deaths of massive stars. Population synthesis allows us to model these binaries through isolated binary evolution, but its predictive power is limited by difficulties in varying the stellar models and their associated uncertainties. We present a new grid of stellar tracks computed with the open-source stellar evolution code MESA, spanning metallicities $10^{-3} \le Z/Z_{\odot} \le 7$. We vary two stellar physics parameters: wind-driven mass loss and the convective boundary mixing (CBM) mechanism. We pair these models with the Method of Interpolation for Single Stellar Evolution (METISSE) and binary population synthesis code COSMIC to obtain synthetic populations of merging BBHs in the local Universe. We find a maximum in the primary mass spectrum near $10M_\odot$ which in most model variations is composed of two sub-populations at $\approx8M_{\odot}$ and $\approx13 M_\odot$, with the higher-mass population dominated by BBHs whose progenitors underwent a mass ratio reversal (MRR). This population also suggests an anticorrelation between higher primary masses and mass ratio, as BBHs with $m_1\gtrapprox10M_\odot$ preferentially undergo MRR and prefer a final mass ratio of $q\approx0.7$. However, the location and relative strength of these two sub-populations is sensitive to our assumed stellar physics: varying both the wind and CBM treatments can merge the MRR and non-MRR populations into a single peak near $9M_\odot$. Variations in our stellar tracks, especially CBM, lead to a factor of $\approx6$ difference in the rate, primarily due to modulation of the common envelope formation channel.
[abstract 15 / 18] (score: 2) - Title: The NANOGrav 15 yr Data Set: Impacts of Customized Chromatic Noise Models on Gravitational Wave AnalysesAuthors: Nikita Agarwal, Gabriella Agazie, Alessandra Amosso, Akash Anumarlapudi, Anne M. Archibald, Zaven Arzoumanian, Anjana Ashok, Jeremy G. Baier, Paul T. Baker, Bence Becsy, Laura Blecha, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Rand Burnette, Robin Case, J. Andrew Casey-Clyde, Yu-Ting Chang, Maria Charisi, Shami Chatterjee, Tyler Cohen, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. DeCesar, Paul B. Demorest, Heling Deng, Lankeswar Dey, Timothy Dolch, Graham M. Doskoch, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Gabriel E. Freedman, Emiko C. Gardiner, Nate Garver-Daniels, Peter A. Gentile, Kyle A. Gersbach, Joseph Glaser, Deborah C. Good, Kayhan Gultekin, Aiden Gundersen, C. J. Harris, Doa Hashemi Asl, Jeffrey S. Hazboun, Ross J. Jennings, Aaron D. Johnson, Megan L. Jones, David L. Kaplan, Anala K. Sreekumar, Luke Zoltan Kelley, Matthew Kerr, Joey S. Key, Nima Laal, Michael T. Lam, William G. Lamb, Bjorn Larsen, T. Joseph W. Lazio, Natalia Lewandowska, Tingting Liu, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Chung-Pei Ma, Dustin R. Madison, Ashley Martsen, Cayenne Matt, Alexander McEwen, James W. McKee, Maura A. McLaughlin, Natasha McMann, Bradley W. Meyers, Patrick M. Meyers, Matthew T. Miles, Chiara M. F. Mingarelli, Andrea Mitridate, Cherry Ng, David J. Nice, Shania Nichols, Stella K. Ocker, Daniel J. Oliver, Ken D. Olum, Timothy T. Pennucci, Benetge B. P. Perera, Polina Petrov, Nihan S. Pol, Henri A. Radovan, Scott M. Ransom, Paul S. Ray, Joseph D. Romano, Jessie C. Runnoe, Alexander Saffer, Shashwat C. Sardesai, Ann Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Levi Schult, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Sophia V. Sosa Fiscella, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Robin Strahler, Abhimanyu Susobhanan, Joseph K. Swiggum, Jacob Taylor, Stephen R. Taylor, Mercedes S. Thompson, Jacob E. Turner, Michele Vallisneri, Rutger van Haasteren, Joris P. W. Verbiest, Sarah J. Vigeland, Haley M. Wahl, Kalista Wayt, Kevin P. Wilson, Caitlin A. Witt, David Wright, Olivia Young,Comments: 28 pages, 17 figures, Submitted to Astrophysical Journal Letters. For questions or comments, please email jeremy.baier@nanograv.org or bjorn.larsen@nanograv.orgSubjects: astro-ph.CO astro-ph.HECreated: 2026-06-26; Updated: 2026-06-30; Datestamp: 2026-06-30
We report updated nHz gravitational wave (GW) significance, characterization, and interpretations using the customized chromatic-noise models (CNMs) developed in Larsen, Baier et al. (2026). for the NANOGrav 15-year data set. We find increased evidence for the Hellings-Downs (HD) correlation signature of the stochastic gravitational wave background (GWB), with a Bayes factor of $1571\pm14$ for HD-correlations over a common uncorrelated red-noise process using a power-law model with $14$ Fourier modes. We find this $\sim8\times$ increase in Bayes factor from Agazie et al. (2023a) is a result of improved noise mitigation. Assuming an analytic null distribution for the frequentist interpulsar correlation statistic, this corresponds to a slightly more significant measurement from $3.16σ$ to $3.32σ$ against the no-correlation scenario. Spectral inference with CNMs brings the power-law GWB amplitude down to $A_{\rm GWB} = 2.1^{+0.6}_{-0.5}\times10^{-15}$ at fixed $γ_{\rm GWB} = 13/3$. In a varied-$γ$ analysis, the spectral index increases to $γ_{\rm GWB}=3.5^{+0.7}_{-0.6}$. We report updates on an all-sky continuous gravitational wave (CW) search as well as select targeted searches and calculate a $3.2\times$ larger detection volume for the NANOGrav detector. With CNMs, we find reduced evidence for a non-Einsteinian, scalar-transverse mode of gravity. Finally, we reinterpret the GWB first with the assumption of an astrophysical background sourced by SMBHBs and then assuming the more exotic origins of cosmic inflation, a first-order cosmological phase transition, and stable cosmic strings. Under both the SMBHB hypothesis and the cosmological hypotheses, we see only marginal shifts in model parameter posteriors which are consistent with the slightly quieter and steeper power-law GWB spectrum.
[abstract 16 / 18] (score: 2) - Title: Confinement-Induced Suppression of Jet Drop Size by Bubble Bursting in Shallow LiquidsAuthors: Zhengyu Yang, Vatsal Sanjay, C. Ricardo Constante-Amores, Jie Feng,Comments: 7 pages, 4 figuresSubjects: physics.flu-dynCreated: 2026-06-26; Updated: 2026-06-30; Datestamp: 2026-06-30
Bubble bursting is a major source of aerosol generation in a wide range of natural and industrial systems. While the resulting JET dynamics have been extensively studied in deep liquid pools, bubble bursting often occurs in shallow liquid layers where the influence of the nearby solid boundary remains poorly understood. Here, we show numerically that a shallow liquid layer produces smaller and more numerous JET drops, even when the initial bubble shape is unchanged. We identify a wall-induced viscous sticking effect that suppresses the upward motion of the cavity bottom, leading to a steeper cavity geometry during capillary-wave focusing. We further develop a semi-empirical scaling law that predicts the JET drop radius as a function of the Ohnesorge number and the initial bubble-wall distance. Our results establish geometric confinement as a governing factor in bubble bursting and provide a framework for predicting and controlling aerosol generation in shallow liquid environments.
[abstract 17 / 18] (score: 2) - Title: Wave Activity at MHD-ion Scales Associated with SwitchbacksAuthors: Kyung-Eun Choi, Oleksiy V. Agapitov, Forrest Mozer, Seung-Ju Yang, Dae-Young Lee, Richard D. Sydora, Lucas Colomban, Liudmyla Kozak, Mingzhe Liu, Marc Pulupa, Jia Huang, Shaosui Xu,Comments: Submitted to The Astrophysical JournalSubjects: physics.space-ph astro-ph.SRCreated: 2026-06-26; Updated: 2026-06-30; Datestamp: 2026-06-30
Magnetic switchbacks (SB) -- the localized MAGNETic structures with MAGNETic field direction inclined at an angle $θ$ relative to the background $B_0$ -- in the young solar wind have been associated with enhanced ion-scale wave activity and local plasma heating. It remains debated whether the apparent wave-power increase is intrinsic or mainly caused by sampling geometry. In this work, we analyze MAGNETic and electric field fluctuations measured by Parker Solar Probe, focusing on the 0.1--3~\(f_{cp}\) frequency band that spans the transition from the MHD inertial range to ion-kinetic scales. By decomposing MAGNETic fluctuations into field-aligned and transverse components and comparing SB and non-SB intervals at the same local MAGNETic field angle, we test whether SBs sample an anisotropic cascade from different viewing angles or host intrinsically amplified wave activity. We find that the transverse MAGNETic power $δB_{\perp}$ is systematically enhanced inside switchbacks across a wide range of MAGNETic field rotation angles $θ$. The enhancement persists even at small and intermediate deflections, where geometric projection alone predicts weak power, indicating an intrinsic origin beyond sampling geometry. The inertial-range spectral indices also remain similar between SB and non-SB intervals despite the enhanced wave power inside SBs, suggesting that the underlying turbulence cascade is largely preserved. This excess $δB_{\perp}$ coincides with elevated proton temperatures and enhanced electric-field fluctuations, supporting the interpretation that SBs act as localized sites of cross-scale energy transfer and ion-scale dissipation in the near-Sun solar wind.
[abstract 18 / 18] (score: 2) - Title: Enhancing VLBI Capability with the SKA-Mid and the Jingdong 120-m Radio TelescopeAuthors: Wen Chen, Jun Yang, Zhixuan Li, Yingjie Li, Niu Liu,Comments: Published in Advancing Astrophysics with the SKA II (AASKAII), 2026 (arXiv:2606.20366). Report-no:AASKAII/Chen01Subjects: astro-ph.IM astro-ph.GACreated: 2026-06-27; Updated: 2026-06-30; Datestamp: 2026-06-30
The Jingdong Radio Telescope (JRT) is a 120-meter fully steerable radio telescope currently under construction in Jingdong County, Yunnan Province, China. Located at a relatively low latitude (24.5 degree), the JRT will enable observations of nearly 90% of the sky. Equipped with two broadband single-pixel receivers covering 1-8 GHz and 6-18 GHz, and a powerful digital backend, the telescope will support single-dish studies of various radio sources-particularly millisecond pulsars for enhancing the detection of nanohertz gravitational waves. In addition to single-dish capabilities, the JRT is expected to contribute approximately 800 hours annually to international Very Long Baseline Interferometry (VLBI) observations via a standard VLBI backend. When operating in conjunction with the phased-up SKA-Mid, the JRT will significantly enhance the technical and scientific capabilities of existing VLBI networks. This paper presents a comprehensive overview of the JRT's VLBI module and explores its potential to improve joint VLBI observations with current VLBI networks. Our analysis suggests that coordinated VLBI observations involving both the SKA-Mid and the JRT have the potential to significantly advance the field. For early sciences, we also highlight a few highly promising scientific cases, e.g. measuring the distance to PSR J0437-4715 with <1 ly accuracy and exploring JET formation with an event-horizon-scale resolution in M60*.
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