Cosmology and Nongalactic Astrophysics · Cross-listed from physics.plasm-ph
Inverse energy transfer in decaying MHD turbulence: A shell-to-shell analysis
Lenard Kasselmann, Philipp Grete, Pranjal Trivedi et al. (+2 more)
In decaying magnetohydrodynamic
turbulence, energy can be transported from small to large scales, known as inverse transfer. We explore the mechanism behind this phenomenon using shell-to-shell transfer functions. Independent of
magnetic net-helicity, large
magnetic scales receive energy directly from the integral scale in both the
magnetic and kinetic reservoirs, leading to increasingly non-local transfer for larger receiving scales. The resulting rate of energy increase in each receiving scale is proportional to its energy, resulting in self-similar, multiplicative growth. Even though the system is magnetically dominated, contributions from kinetic-
magnetic and
magnetic-
magnetic energy-exchange are similar in magnitude. In the case of vanishing net-helicity, transfer functions between the positively and negatively helical parts of the field are computed. We find that inverse transfer only occurs within each helical sector, not across them. Our findings are consistent with the theory underlying the conservation of the Hosking integral, which explains inverse transfer as merging of local
magnetic islands with equal-signed helicity.
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All authors Lenard Kasselmann, Philipp Grete, Pranjal Trivedi, Marcus Brüggen, Robi Banerjee
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Effective chemical potential and its phenomenological implications for the Hubble parameter
L. L. Sales and F. C. Carvalho
In cosmological models, the Hubble parameter is determined by the time
evolution of the scale factor, and current observations reveal a persistent tension between its values inferred from different probes, such as Cepheid variable
stars and the
cosmic microwave background. Within Tsallis' statistical framework, we identify two distinct definitions of fugacity associated with relativistic and non-relativistic regimes. For the non-relativistic sector, we introduce an effective chemical potential and establish its connection with the Gibbs free energy. We then explore a phenomenological correspondence between this effective chemical potential and an Unruh-like temperature associated with accelerated trajectories in an expanding cosmological background. As an application, we derive an effective expression for the Hubble parameter that includes a statistics-dependent contribution arising from the non-relativistic matter sector. This contribution suggests that non-Gaussian statistical effects, when consistently incorporated in the non-relativistic matter sector, can enhance the sensitivity of the expansion rate to underlying thermostatistical assumptions, achieving a substantial increase in sensitivity by approximately ten orders of magnitude when compared with previous relativistic constructions that investigated, at a phenomenological level, the discrepancy observed in current determinations of the Hubble constant.
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Solar and Stellar Astrophysics
Study of the 1/f spectrum using virtual spacecraft sampling in MHD turbulence
Maia Brodiano, Facundo Pugliese, Nahuel Andrés et al. (+1 more)
We investigate the appearance of a low-frequency 1/f
magnetic spectrum in three-dimensional incompressible magnetohydrodynamic
turbulence using direct numerical simulations and virtual spacecraft sampling. Our goal is to determine how the measured temporal spectra depend on the mean
magnetic guide field, the probe velocity relative to the Alfvén speed, and the sampling angle with respect to the guide field. We find that the clearest 1/f ranges are obtained for stronger guide fields and are favored by faster sampler trajectories oriented more nearly perpendicular to the mean
magnetic field. To characterize this behavior, we introduce a quantitative score that measures the quality and spectral coverage of the detected 1/f interval. We further show that, as the probe speed increases, the measured temporal spectra become progressively more consistent with a direct mapping between spatial and temporal fluctuations, particularly for nearly perpendicular sampling in the strong guide field case. These results indicate that the presence and clarity of a temporal 1/f range depend not only on the underlying turbulent dynamics, but also on the geometry and speed of the sampling process, with implications for the interpretation of low-frequency in situ measurements in the
solar wind.
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All authors Maia Brodiano, Facundo Pugliese, Nahuel Andrés, Pablo Dmitruk
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Reconstructing ACT-compatible and GW170817-compatible Einstein-Gauss-Bonnet Inflation from the Observational Indices
V.K. Oikonomou
In this work we use an inverse reconstruction technique for constructing ACT-compatible and GW170817-compatible Einstein-Gauss-Bonnet inflationary theories. From a given tensor-to-scalar ratio using the reconstruction technique, we find which scalar Gauss-Bonnet coupling function and which scalar potential can yield the given tensor-to-scalar ratio. We present the formalism and the viable theories pass a series of observational tests, including the amplitude of the scalar perturbations, which is non-trivial for Einstein-Gauss-Bonnet theories. We present four viable models of inflation that pass all the observational tests.
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Instrumentation and Methods for Astrophysics
The Ultraviolet View of Star and Planet Formation: Disks, Accretion, and Outflows with the Hubble Space Telescope into the 2030s
Kevin France, Eric Gaidos, Catherine Espaillat et al. (+2 more)
The spatial distribution and lifetime of molecular gas in the inner regions of young circumstellar disks are key to understanding the formation of planetary systems. Gas-rich disks are observed to disperse in the first ~10 Myr, and recent observational and theoretical evidence suggests that circumstellar disks winds may dominate the removal of angular momentum from the disk, allowing it to dissipate through
accretion onto the central
star and through low-velocity (<~30 km/s)
outflows. The Hubble Space
Telescope has revolutionized our understanding of the disks,
accretion, and
outflow processes that drive the
evolution of
planet-forming disks and is poised to answer the key questions in the field in the coming decade. We describe how HST's ultraviolet capabilities can address these questions and identify key goals and high-priority observations for HST into the 2030s.
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All authors Kevin France, Eric Gaidos, Catherine Espaillat, Carlo F. Manara, Edwin Bergin
Earth and Planetary Astrophysics
The dynamical structure of the Earth co-orbital region and implications for the near-Earth asteroid population
Marco Fenucci, Óscar Rodríguez, Melaine Saillenfest et al. (+1 more)
We investigate the structure of the Earth co-orbital region at low eccentricity and low inclination using a semi-analytical model of the 1:1 mean-motion resonance. The dynamics of asteroids in co-orbital motion with the Earth is described through a resonant semi-secular
Hamiltonian, allowing the classification of orbits into circulation, Trojan, horseshoe, and quasi-satellite states. By systematically exploring the phase space in the space of the orbital elements, we compute the fraction of each type of motion and quantify how different co-orbital states fill the Earth co-orbital region. We find that horseshoe orbits dominate the phase space, occupying more than half of the volume, followed by Trojan and circulating orbits, while quasi-satellites represent only a small fraction. The distribution of co-orbital states exhibits strong inhomogeneities, particularly as a function of the argument of perihelion, with clear concentration regions of horseshoe orbits associated with node-crossing geometries. We also study the short-term stability of this portion of phase space by means of the MEGNO indicator, and how the level of chaos differs between different co-orbital states. Finally, we discuss the implications of these results for the expected population of Earth co-orbitals and for planetary defence, showing that a large fraction of co-orbitals remains undiscovered.
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All authors Marco Fenucci, Óscar Rodríguez, Melaine Saillenfest, Laura Faggioli
Solar and Stellar Astrophysics
A Probabilistic Calibration Procedure for the CORSAIR Polarimeter
Alan Hsu, Jenna Samra, Steven Tomczyk et al. (+1 more)
We present a novel
Bayesian model and a corresponding robust, probabilistic calibration procedure for the CORSAIR polarimeter that can be applied to other polarimeters. Our calibration procedure combines existing Mueller
matrix representations of polarimeters with
Bayesian methods, and computes the posterior distribution of the parameters by collecting data from the polarimeter at different states. We show that the
algorithm is able to converge and recover a well-constrained posterior of the free parameters with a credible interval that is consistent with the ground truth values. Posterior predictive checks indicate that our generative model with inferred parameters can reproduce the calibration data within the predictive uncertainty, and captures the dominant systematic effects of the calibration procedure. We further show that we can propagate calibration uncertainties in the distributions to downstream reconstructions of Stokes measurements and
magnetic-field estimates. We find that the contribution of calibration uncertainty towards the reconstructed results is minimal relative to that of the
photon noise uncertainty, indicating that estimates using our
Bayesian calibration
algorithm can achieve
photon noise-limited measurements in the
magnetic-field parameters. Finally, we test the
Bayesian calibration
algorithm on a lab prototype of the CORSAIR polarimeter, and show that it converges and closely recovers theoretical estimates of the free parameters from real-world measurements.
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All authors Alan Hsu, Jenna Samra, Steven Tomczyk, Maxim Kramar
Astrophysics of Galaxies
Bar-driven gas redistribution suppresses star formation in spiral galaxies: Evidence from dust lanes in NGC 3351
Koshy George and Smitha Subramanian
We present observational evidence, based on high-resolution imaging from HST, ALMA, and AstroSat/UVIT, that the redistribution of gas driven by the bar in the face-on spiral
galaxy NGC 3351 results in suppressed
star formation in its central regions.
Dust and molecular gas coexist in
galaxies, allowing
dust lanes observed in
galaxies to be used to probe the distribution of gas. In the central regions of NGC 3351, covered by the
stellar bar,
dust lanes are visible in the HST F438W-F814W color map, but surprisingly, these areas lack molecular gas and recent
star formation. The inward orientation of the
dust lane morphology towards the
galaxy's center suggests that molecular gas may have once been present in this region, but was redistributed to the center due to the
stellar bar's action. The direction of
dust lanes, therefore, indicates the past inflows of gas toward the
galaxy center, with their morphology consistently oriented inward along the bar. These findings support a scenario where the
stellar bar has efficiently channeled molecular gas into the
nucleus, building the central reservoir while suppressing
star formation along the bar.
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Astrophysics of Galaxies
The Celestial Reference Frame at K Band: The CRF-K-2025 Catalog
David Gordon, Aletha de Witt, Christopher S. Jacobs et al. (+10 more)
We present an updated K band (24 GHz) celestial reference frame (CRF) constructed from 3.5 million Very Long Baseline Interferometry (VLBI) observations collected during 211 observing epochs between May 2002 and December 2025 using the Very Long Baseline Array (VLBA), the HARTRAO-HOBART26 baseline, the HARTRAO-YEBES40M baseline, and the Korean VLBI Network (KVN) augmented with several other VLBI stations. We have successfully observed and determined precise angular coordinates for 1317 compact extragalactic
radio sources, essentially
quasars, covering the full sky. This updated K band catalog is designated as CRF-K-2025. The precision of CRF-K-2025 is characterized by median scaled uncertainties of 60 and 104 micro-arc-seconds in right ascension and declination, respectively. The increase in number of observations and sensitivity over earlier K band campaigns has resulted in a catalog with 493 additional sources and a precision approximately 25% better than the ICRF3-K catalog, and similar to the ICRF3-SX catalog. At K band, these
quasar radio sources generally show less extended emission than at lower frequencies and thus can potentially provide a more stable long term celestial reference frame than at the standard S/X (2.3/8.4 GHz) observing bands of ICRF3-SX.
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All authors David Gordon, Aletha de Witt, Christopher S. Jacobs, Hana Krasna, Alessandra Bertarini, Jamie McCallum, Jonathan Quick, Cristina Garcia-Miro, Taehyun Jung, Jeffrey A. Hodgson, Whee Yeon Cheong, Sang-Sung Lee, Do-Young Byun
Earth and Planetary Astrophysics
Reading between the rings: observed dust ring properties as probes of planet masses
Amena Faruqi, Jessica Speedie, Ralph E. Pudritz et al. (+1 more)
We hypothesise that
dust rings in protoplanetary discs formed by an embedded
planet should have properties that reflect the
planet's mass. We use 2D hydrodynamical simulations of
planet-disc interactions to investigate this, focusing on
planets ranging 0.5-2.0x the pebble-isolation mass, for three different aspect ratios. We find the ring's
dust mass, peak location, and width to correlate with
planet mass. We confirm a positive linear relationship between a
planet's Hill radius and the location of a ring's density peak and demonstrate how this relationship can be used to constrain
planet masses in observed systems by applying it to PDS 70. The
dust ring width and mass change with
planet mass for
planet masses up to the pebble-isolation mass, beyond which they become constant. The steepness of the gas pressure radial profile is asymmetric, with the direction of the asymmetry being determined by whether the
planet mass is above or below the pebble-isolation mass. We therefore propose a new way to define the pebble-isolation mass: the minimum
planet mass which perturbs the gas enough for the pressure gradient interior to the pressure maximum to exceed the pressure gradient exterior to it. We discuss how our findings could be used to constrain or estimate
planet masses from gas or
dust observations of discs with measurable substructures and apply our results to 5 discs in the exoALMA sample to estimate
planet masses and constrain disc aspect ratios. We also discuss how the potential for planetesimal formation in a ring varies with
planet mass.
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All authors Amena Faruqi, Jessica Speedie, Ralph E. Pudritz, Farzana Meru
Solar and Stellar Astrophysics
Hydrodynamic Response of Mildly Evolved Common Envelope Donors in Luminous Red Novae
Tenley Hutchinson-Smith, Angela Twum and Enrico Ramirez-Ruiz
Luminous red novae trace unstable binary interactions in which common-envelope
evolution can produce either a
stellar merger or a surviving binary following envelope ejection. Recent population studies suggest that a substantial fraction of these systems originate from mildly evolved donors whose structures occupy an intermediate regime between simplified polytropic envelopes and highly stratified
giant stars. We present a suite of three-dimensional hydrodynamic simulations of mildly evolved donors interacting with embedded companions spanning a range of mass ratios and central density concentrations. We show that the hydrodynamic
evolution is strongly regulated by the donor central concentration, parameterized by the ratio $\rho_c/\bar{\rho}$. Donors with similar values of $\rho_c/\bar{\rho}$ exhibit similar inspiral morphologies and mass-ejection histories despite substantial differences in
stellar mass and radius. Systems with relatively modest central concentration undergo rapid inspiral dominated by local orbital-energy deposition, while more centrally concentrated donors develop prolonged expansion-driven phases in which shocks and large-scale envelope motions redistribute deposited energy and angular momentum throughout the
star. In this regime, the envelope itself becomes dynamically important in driving continued mass loss long after the rapid plunge-in phase slows. These results challenge semi-analytic models of luminous red novae that assume nearly instantaneous envelope ejection and suggest that their observed diversity may depend not only on total ejecta mass, but also on the temporal structure of the
outflow.
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Instrumentation and Methods for Astrophysics
A Partially Supervised Latent-Space Variational Autoencoder for Generating Neutron Star Equations of State
Tianqi Zhao, Fanglida Yan, Alex Ross et al. (+1 more)
We develop a partially supervised latent-space variational autoencoder (PSL-VAE) framework to reconstruct and generate
neutron star (NS) equations of state (EOS). The PSL-VAE consists of an encoder network that maps high-dimensional EOS data into a lower-dimensional latent space and a decoder network that reconstructs the full EOS from the latent representation. The latent space includes supervised NS observables derived from the training EOS data, as well as variational latent variables that capture additional EOS features learned automatically. Using a PSL-VAE trained on a Skyrme EOS
dataset, we find that a latent space consisting of two supervised observables, the maximum mass $M_{\max}$ and the canonical radius $R_{1.4}$, together with a single variational latent variable associated mainly with the EOS near the crust-core transition, is sufficient to reconstruct Skyrme EOSs with high fidelity. The decoder reconstructed EOSs reproduce $M_{\max}$ and $R_{1.4}$ with mean absolute percentage errors within $0.08\%$. Sampling the latent space generates new EOSs that are causal, thermodynamically stable, and consistent with imposed constraints on the supervised observables. The framework therefore provides a compact and physically interpretable parameterization of the NS EOS that is well suited for
Bayesian inference with multimessenger observations, including
pulsar mass-radius measurements and gravitational wave data.
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All authors Tianqi Zhao, Fanglida Yan, Alex Ross, James M. Lattimer
Astrophysics of Galaxies
MAGAZ3NE: Spatially Resolved Ages and Chemical Abundances of Ultra-Massive Quiescent Galaxies at z $\sim$ 3.5 using JWST/NIRSpec IFU
Adit H. Edward, Jacqueline Antwi-Danso, Adam Muzzin et al. (+14 more)
We present spatially-resolved measurements of
stellar age, [Fe/H], and [$\alpha$/Fe] in three ultra-massive ($\rm{log(M_{\ast}/M_{\odot})>11}$), compact ($\rm{R_e} \lesssim 2$ kpc) quiescent
galaxies at $z\sim3.5$ using JWST/NIRSpec IFU spectroscopy. These observations provide the first spatially-resolved constraints on $\alpha$-enhancement at this epoch, enabling a direct test of quenching mechanisms before late-time assembly processes such as mergers can erase chemical signatures. The central regions of all three
galaxies show both uniformly young ages ($\approx0.6-0.7$ Gyr) and elevated [$\alpha$/Fe] ($\approx0.2-0.5$), indicating rapid, enhanced
star formation shortly before recent quenching. Beyond the cores, two
galaxies display positive age gradients and negative [$\alpha$/Fe] gradients, consistent with rapid merger-driven quenching, while the third shows a flat age profile indicative of uniform quenching. The [Fe/H] gradients are also consistent with these trends, though we note that the
metallicities reported by codes using $\alpha$-enhanced models differ significantly ($\approx0.2-0.4$ dex) from those reported using
solar-scaled templates. These data demonstrate that quenching pathways are diverse by $z\sim3.5$, with rapid, merger-driven quenching already operating in a subset of massive quiescent
galaxies in the first two billion years of
cosmic time. Furthermore, these results establish that explicit treatment of $\alpha$-enhancement is essential for interpreting the
star-formation histories of the earliest quenched systems.
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All authors Adit H. Edward, Jacqueline Antwi-Danso, Adam Muzzin, Ben Forrest, Ian McConachie, Aliza Beverage, Wenjun Chang, M. C. Cooper, Percy Gomez, Massissilia L. Hamadouche, Aurélien Henry, Han Lei, Danilo Marchesini, Allison Noble, Stephanie M. Urbano Stawinski, Gillian Wilson, M. E. Wisz
Instrumentation and Methods for Astrophysics
VROOM-SBI: A Fast Simulation-Based Bayesian Inference Methodology for Stokes QU-Fitting in Radio Interferometry
Arpan Pal and Preshanth Jagannathan
Bayesian QU-fitting is among the most accurate approaches for line-of-sight Faraday inference, but its per-pixel computational cost has made survey-scale application infeasible. QU-fitting is an alternative to Faraday synthesis with comparable accuracy in recovering line-of-sight Faraday components, but it has historically been computationally prohibitive at survey scale. Fitting to the Stokes spectra in $Q$ and $U$ through
Bayesian inference is effective but slow. We introduce VROOM-SBI, which uses simulation-based inference, particularly neural posterior estimation, to speed up inference. Our results are comparable to both Faraday synthesis and QU-fitting, and deliver a speedup of $\sim$$500$ over classical QU-fitting implementations. We provide an open code repository and tools along with trained models via HuggingFace for the four standard depolarization models in common use, trained on VLA L-band frequency coverage.
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Instrumentation and Methods for Astrophysics
Probabilistic Data-Driven Modelling of Astrophysical Transients: The Neural Process Family for Ultrafast and Class-Agnostic Light Curve Reconstruction with NightLANP
Siddharth Chaini, Federica B. Bianco and Ashish Mahabal
Astrophysical observations from Earth are subject to weather, environmental, and scientific constraints that lead to sparse, irregular light curves. On the eve of the Vera C. Rubin Observatory Legacy Survey of Space and Time, its
dataset offers unprecedented opportunities for transient science. Yet a key challenge remains its cadence, sparse and irregular across six bands, limiting inference. Interpolation helps mitigate this, with Gaussian Processes the standard, but they struggle with cross-band correlations, require a priori kernel specification, and must be fit to each light curve individually, hence scaling poorly. Here, we introduce the neural process family for light curve reconstruction, combining the probabilistic framework of Gaussian Processes with the scalability of deep learning. By meta-learning on diverse simulated transients, Attentive Neural Processes shift the bulk of computation to training, enabling rapid, amortized inference with a class-agnostic model. Evaluated on realistic Rubin cadences across 15 transient classes, we show that even an unoptimized, out-of-the-box Attentive Neural Process consistently outperforms all
benchmarks – a suite of Gaussian Processes and neural networks – on every tested metric, spanning regression quality, astrophysical feature recovery, and probabilistic calibration. Our model interpolates all bands simultaneously in microseconds, over four orders of magnitude faster than the next-best neural
benchmark and five faster than Gaussian Processes, demonstrating the potential of neural processes for the nightly Rubin alert stream. Attentive Neural Processes avoid the overconfidence of standard neural networks and the underconfidence of Gaussian Processes, delivering sharp, well-calibrated uncertainties. This work establishes the neural process family as a scalable, probabilistic foundation for real-time transient science in the Rubin era.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
From WIMP to FIMP during reheating: collider vs non-collider probes for p-wave annihilation
Dipankar Pradhan, Niloy Mondal, Abhik Sarkar et al. (+4 more)
By examining the transition from freeze-out to freeze-in dark matter (DM) production within the framework of perturbative reheating, where DM interacts with the visible sector through effective operators of dimension six, we have investigated how a broad range of new physics probes can reveal the nature of the pre-BBN Universe. Incorporating constraints from direct and indirect DM searches, invisible decay measurements,
collider experiments, and gravitational wave observations, our analysis demonstrates that both current and forthcoming experimental sensitivities can serve as powerful tools for probing as well as constraining the post-inflationary era, together with new physics beyond the SM. Our analysis demonstrates that
collider experiments at both the intensity and energy frontiers can impose strong bounds on derivative operators whose interactions are typically p-wave suppressed, and therefore only weakly constrained by astrophysical observations. In particular, these complementary searches can significantly restrict the allowed reheating temperature, DM mass and effective interaction scale required to reproduce the observed DM abundance for DM produced during the epoch of reheating.
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All authors Dipankar Pradhan, Niloy Mondal, Abhik Sarkar, Anupam Ghosh, Shashwat Sharma, Mathew Thomas Arun, Basabendu Barman
Cosmology and Nongalactic Astrophysics
The Ellis and Baldwin test of the Cosmic Dipole: Exploring the impact of multiple flux density cuts
Vasudev Mittal and Geraint F. Lewis
The
cosmic dipole tension - the discrepancy between the
Cosmic Microwave Background kinematic dipole and the matter dipole inferred from all-sky surveys poses a significant challenge to the Cosmological Principle, which dictates that the universe is homogeneous and isotropic at the largest scales. Traditional measurement of the matter dipole requires selecting an appropriate limiting flux and calculating the dipolar modulation using sources brighter than the flux. This approach, however, ignores the shape of the source luminosity function (LF) and deprives the analysis of this crucial information. In this study, we present a new approach to calculate the matter dipole by integrating the source flux distribution into the analysis. We achieve this by dividing the catalogue into disjoint flux bins and simultaneously fitting the matter dipole across them. For non-power-law LFs, this method gives a higher Bayes factor - and hence a better description of the matter dipole - as compared to the traditional approach. The method works best when the flux cuts are selected in regions where the LF's shape changes significantly. We discuss the feasibility of this method for upcoming cosmological surveys and show that it has the potential to yield decisive results at both
radio and infrared wavelengths.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Probing the dynamical inverse seesaw mechanism with low-frequency gravitational waves
Debasish Borah, Sounak Dutta, Partha Kumar Paul et al. (+2 more)
We study the possibility of probing the dynamical inverse seesaw mechanism for the origin of light
neutrino masses via the detection of
stochastic gravitational waves (GW) in the low-frequency regime currently being probed by
pulsar timing arrays. As the
lepton number-violating term in inverse seesaw typically remains in the sub-MeV ballpark, its dynamical origin naturally brings the possibility of a low-scale first-order phase transition, which can be probed at low-frequency GW experiments. We also find interesting complementarity with heavy neutral
lepton searches, as GW experiments remain sensitive to parameter space with small active-sterile mixing, which is out of reach for most particle physics experiments.
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All authors Debasish Borah, Sounak Dutta, Partha Kumar Paul, Indrajit Saha, Narendra Sahu
Astrophysics of Galaxies
TRINITY: A coupled model of winds, radiation, and photoionised gas in molecular clouds. I. Methods and validation
Jia Wei Teh, Ralf S. Klessen, Simon C. O. Glover et al. (+1 more)
Multi-wavelength surveys place cloud dispersal at 1-5 Myr after massive
stars emerge, before the first
supernovae. Whether a cloud disperses, re-collapses, or leaks Lyman-continuum (LyC)
photons depends on how pre-
supernova winds, radiation pressure, and photoionised-gas pressure ($P_{\rm HII}$) couple to the shell. We introduce TRINITY, a 1D thin-shell code that succeeds WARPFIELD. TRINITY evolves the bubble-shell structure under winds,
supernovae, direct and
dust-reprocessed radiation pressure, $P_{\rm HII}$, and
gravity. A phase-aware prescription drives the shell with the larger of the hot-bubble and photoionised pressures when energy-driven, and $P_{\rm HII}$ plus ram pressure when momentum-driven. The initial cloud may be uniform, a piecewise power law, or a Bonnor-Ebert sphere; shell structure, hot-bubble cooling,
photon absorption, and LyC escape evolve with the dynamics. We validate against analytic wind and photoionisation limits and survey clouds of mass $10^5$-$10^{6.5}\,M_\odot$, core density $10^3$-$10^4$ cm$^{-3}$, and
star-formation efficiency $\varepsilon=0.01$-$0.30$. $P_{\rm HII}$ enlarges the shell radius by roughly 17% at 10 Myr in the fiducial run. At higher efficiency, the energy-driven phase lasts under 1 Myr, radiation pressure stays sub-dominant, and $P_{\rm HII}$ remains dynamically important in the momentum-driven phase. Cloud structure sets both phase durations and outcomes: at fixed mass, core density, and efficiency, homogeneous and shallow clouds re-collapse while a steep $\rho\propto r^{-2}$ cloud keeps expanding, and Bonnor-Ebert clouds disperse roughly 55% later than homogeneous ones. Thus $P_{\rm HII}$ and cloud structure both shape feedback-driven expansion even when the
stellar population is fixed. TRINITY is an efficient, interpretable framework to map feedback dominance across cloud parameter space and resolved H II regions.
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All authors Jia Wei Teh, Ralf S. Klessen, Simon C. O. Glover, Kathryn Kreckel
Instrumentation and Methods for Astrophysics
DebrisWatch II: Digging deeper for geosynchronous debris
James A. Blake, Benjamin F. Cooke, Cristina Paragini et al. (+27 more)
The geosynchronous (GSO) debris environment is continually evolving. Regular monitoring of the region is consequently of great importance, though the trade-off between coverage and sensitivity makes this challenging for the population of optically faint debris, where collecting area becomes a pivotal factor. Surveys conducted with large-aperture
telescopes have provided crucial insights into the nature of this largely uncharacterised population. In this paper, we revisit a survey conducted with the 2.54 m Isaac Newton
Telescope (INT), presenting an overhaul of the astrometric calibration and object detection stages of the original analysis pipeline. We apply a blind stacking technique to boost target recovery, unearthing 25 tracklets previously missed by single-frame extraction methods, and pushing the sensitivity limit fainter by 1 magnitude. The same
algorithm is applied to a contemporaneous
dataset, captured with a 36 cm astrograph, enabling performance benchmarking through the attempted recovery of INT detections from commercial-off-the-shelf observations. We achieve sub-arcsecond astrometric accuracy through a combination of improved
star trail centroiding and iterative distortion fitting, allowing short arc initial orbit solutions to be obtained. High-cadence light curves extracted for trailing detections indicate that faint fragments are proportionally more variable than bright derelicts, with many exhibiting photometric signatures of rapid tumbling, often straddling the image noise floor. Lastly, we present preliminary findings from a follow-up multi-national observation campaign, utilising
telescopes in Australia, Japan and La Palma. As space traffic management concerns begin to extend beyond GSO altitudes, scientifically-driven surveys of high-altitude orbits have an important role to play in characterising the faint debris environment.
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All authors James A. Blake, Benjamin F. Cooke, Cristina Paragini, William Feline, Christopher A. Onken, Don Pollacco, Grant Privett, Toshifumi Yanagisawa, Robert Airey, Ioannis Apergis, Roberto Armellin, Lily Beesley, Paul Chote, Anna-Maria Cutolo, Stuart Eves, Tomoko Fujiwara, Daisuke Kuroda, Isobel S. Lockley, Alexander MacManus, James McCormac, Morgan A Mitchell, Tokuhiro Nimura, Kota Nishiyama, Shin-Ichiro Okumura, Thomas Schildknecht, Billy Shrive, Seitaro Urakawa, Dimitri Veras, Phineas Whitlock, Christian Wolf
High Energy Astrophysical Phenomena
BlackHoleWeather – Jet-regulated chaotic cold accretion across the meso scale: Variability and kinematics
Vieri Cammelli, Massimo Gaspari, Filippo Barbani et al. (+10 more)
Chaotic cold
accretion (CCA) predicts that supermassive black holes are fed by multiphase clouds condensing from turbulent hot atmospheres. In jet-regulated systems cold gas must also remain dynamically connected to the central
accretion region. We investigate how a self-regulated kinetic jet modifies the kinematics, radial transport, and variability of CCA across the meso-scale of a typical
galaxy-group atmosphere. The runs differ only in turbulent driving strength. We measure
accretion histories, Eddington ratios, power spectra, phase-separated mass fluxes, projected k-plots, and cooling-to-eddy-time (C-ratio) profiles. Both runs become CCA-fed once precipitation begins, with
accretion rising from Bondi-like to strongly super-Bondi values while remaining mostly low-Eddington and mechanically dominated. The strongly stirred run develops an early stormy phase with extended condensation, bursty feeding, and strong inflow/
outflow variability, but later enters a cloudy phase in which cold and warm gas persist at meso- and inner macro-scales while sink coupling weakens. The calmer run maintains a compact rainy state with a longer-lived central reservoir.
Accretion-rate spectra show flicker-like low-frequency slopes and red-noise tails; in the cloudy phase, the normalization drops and the low-frequency slope flattens. Phase-separated fluxes show fountain-like recycling in the strongly stirred run, but inner-kpc recycling in the calmer run. The jet excavates a hot channel where sustained condensation is suppressed, while C~1 is reached mostly outside the cone and near the jet-ambient interface. Jet-regulated CCA is controlled by meso-scale transport, not only by cold-gas production. Within the BlackHoleWeather framework, combined k-plot and C-ratio diagnostics are crucial to distinguish cold gas that is merely present from cold gas dynamically linked to SMBH feeding.
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All authors Vieri Cammelli, Massimo Gaspari, Filippo Barbani, Olmo Piana, Giovanni Stel, Davide M. Brustio, Valeria Olivares, Roberto Serafinelli, Pasquale Temi, Francesco Salvestrini, Michael Reefe, Filippo M. Maccagni, Francesco Tombesi
High Energy Astrophysical Phenomena
The strength of Type-C quasi-periodic oscillations in black hole X-ray binaries correlates with the jet inclination
F. M. Vincentelli, N. Bollemeijer, A. Veledina et al. (+10 more)
X-ray quasi-periodic oscillations (QPOs) are a characteristic feature of low-mass X-ray binaries (LMXBs). These oscillations have been studied for decades and revealed a rich and complex phenomenology that is still not fully understood. RXTE archival studies have shown that the amplitude of these oscillations differs significantly between black holes (BH) with high or low inclination. Yet, the actual dependence on inclination has never been adequately estimated. Thanks to the improvement of inclination measurements through
radio observations and the recent observations by the HXMT satellite, we quantified for the first time the dependence of Type-C QPO amplitudes on the jet inclination of individual BH LMXBs. Our analysis reveals the presence of a significant linear correlation up to 8 Hz, strengthening the case for a ”geometrical” origin of the QPOs. In addition, for a given QPO frequency, we observe systematically lower amplitudes during the decay of outbursts compared to the rise. This data collection represents a key
benchmark for any QPO model. Our comparison with the predictions from a precessing hot flow shows that the amplitude of the QPOs can be reproduced by this scenario if the
spin-orbit misalignment is at least $\approx$10-15$^\circ$.
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All authors F. M. Vincentelli, N. Bollemeijer, A. Veledina, D. Altamirano, Q. Bu, F. Carotenuto, P. Casella, Y. Cavecchi, R. Ma, G. Marcel, G. Mastroserio, S. Motta, L. Zhang
Astrophysics of Galaxies
Reconstructing the Globular Cluster Initial Mass Function from Present-Day Globular Cluster Systems
Elizabeth Moreno-Hilario, Hui Li and Luis A. Martinez-Medina
The near-universal turnover mass of the present-day globular cluster mass function (GCMF), $M_{\rm TO} \sim 2 \times 10^5\ {\rm M_\odot}$, is a well established observational feature across
galaxies of different types and masses, providing an important empirical
benchmark for understanding the globular cluster initial mass function (GCIMF). Competing explanations of this property invoke either dynamical
evolution from an initial power-law distribution or an imprint of cluster formation physics. We address this problem by reconstructing the high-mass regime of the GCIMF by inverting the mass loss due to dynamical
evolution of present-day globular cluster systems across a wide range of host
galaxy masses. Our method is based on an environment-dependent mass-loss model calibrated by direct $N$-body simulations in time-dependent
tidal fields, enabling a mapping between observed cluster masses and their progenitor values without assuming a priori a functional form for the GCIMF. We apply our method to
galaxies spanning
halo masses of $\sim10^{9}$ - $10^{12}\ {\rm M_\odot}$, combining systems with individually measured globular cluster masses as well as large statistical samples constructed from observed global properties. The recovered GCIMFs are systematically shifted towards higher masses and exhibit a power-law behavior at the high-mass end. The inferred slopes vary across
galaxies and show a strong correlation with host
halo mass, with more massive
galaxies exhibiting steeper high-mass slopes. Our results suggest that the slope of the GCIMF depends on the
galactic properties and provides a direct empirical link between present-day globular cluster systems and their high-
redshift progenitors.
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Astrophysics of Galaxies
BlackHoleWeather – Spin-coupled chaotic cold accretion across the meso scale: Variability and kinematics
Olmo Piana, Massimo Gaspari, Vieri Cammelli et al. (+10 more)
Supermassive black hole (SMBH)
spin records the vector history of
accretion. In chaotic cold
accretion (CCA), this history is set by clouds and filaments whose torques can add coherently, cancel, or reverse before reaching the horizon-scale closure. We test whether
halo stirring regulates SMBH
spin by changing the radial continuity and torque coherence of the meso-scale
accretion bridge. We focus on
spin evolution, jet-axis reorientation,
accretion variability, and CCA kinematics. We analyse four 3D hydrodynamical simulations in a 100-kpc box, reaching sub-pc resolution, including SMBH
spin-coupled jet feedback. All runs use the Hybrid SMBH
spin model validated in a companion paper. Two simulations maintain continuous driven solenoidal
turbulence, while two matched controls let the same initial turbulent field decay. The main effect of persistent stirring is to disrupt mass and angular-momentum continuity across the meso-scale bridge. Although all runs develop comparable macro-scale inflow, in the driven-
turbulence suite, gas struggles to reach pc scales, and the radial
accretion rate drops by 2-3 orders of magnitude. Torque delivery in this case is fragmented and cancellation-dominated. The interrupted-
turbulence suite, on the other hand, preserves a connected gas channel to the sink, while sustaining higher torque coherence. Driven runs therefore settle to slow effective jet-axis drift, whereas interrupted runs maintain reorientation rates higher by about two orders of magnitude and can briefly reach a few degrees during coherent retrograde episodes. The same split appears in power spectra and k-plots: connected rain enhances low-frequency
accretion power and produces narrower, phase-ordered kinematics, while stirring steepens high-frequency damping and broadens the gas velocity loci for all phases.
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All authors Olmo Piana, Massimo Gaspari, Vieri Cammelli, Filippo Barbani, Davide M. Brustio, Giovanni Stel, Valeria Olivares, Ashkbiz Danehkar, Pasquale Temi, Roberto Serafinelli, Francesco Salvestrini, Filippo M. Maccagni, Francesco Tombesi
Astrophysics of Galaxies
BlackHoleWeather – Chaotic cold accretion across the meso-scale: Morphology and thermodynamics
Filippo Barbani, Massimo Gaspari, Vieri Cammelli et al. (+12 more)
Supermassive black holes (SMBHs) self-regulate
galaxies, groups, and clusters, yet the pathway transporting gas from
halo scales to sub-pc radii remains debated. In hot stratified atmospheres, subsonic
turbulence can trigger nonlinear thermal instability and a multiphase condensation cascade, producing chaotic time-variable BH `weather'. A key missing link is how the meso-scale connects
halo rain to
nuclear inflow. We study
turbulence-driven condensation and chaotic cold
accretion (CCA) in a group-scale
halo, quantifying how the stirring level shapes multiphase morphology, thermodynamics, and SMBH feeding. We ran 3D hydrodynamic hyper-zoom simulations with a GPU-accelerated code, including cooling and driven subsonic
turbulence in a hot intragroup
halo. Two endpoint runs bracket weak and strong stirring, capturing distinct BH weather states. In both regimes the atmosphere becomes thermally unstable and develops a multiphase medium spanning 8-10 dex in temperature and density. Strong stirring delays cold gas
accretion and sustains an extended filament-rich rain pattern to kpc radii (`stormy' CCA), with broader thermodynamic distributions beyond the
nucleus. Weak stirring triggers earlier condensation but yields a more compact rain, with most cold gas confined within 100 pc (`rainy' CCA). At micro-scales the inflow is partly mediated by a clumpy rotating
torus. Despite large differences in condensed cold mass, the BH
accretion rate is recurrently boosted by up to 100x above the hot-mode Bondi baseline and varies weakly between the weather regimes, indicating that feeding is regulated primarily by how efficiently multiphase structures couple to the central inflow. Modest
turbulence changes are sufficient to shift the same hot
halo between stormy (extended) and rainy (centralized) BH weather, providing a quantitative multiscale baseline for interpreting multiphase CCA and SMBH feeding.
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All authors Filippo Barbani, Massimo Gaspari, Vieri Cammelli, Olmo Piana, Fred J. Jennings, Davide M. Brustio, Giovanni Stel, Valeria Olivares, Filippo M. Maccagni, Martin Fournier, Francesco Tombesi, Pasquale Temi, Fabrizio Fiore, Roberto Serafinelli, Ashkbiz Danehkar
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Neutrino-antineutrino superfluidity
Damiano F. G. Fiorillo, Georg G. Raffelt and Günter Sigl
Despite their feeble interactions, dense astrophysical
neutrinos can behave collectively, exchanging
flavor through waves of the
neutrino plasma. Can collective interactions also induce pairing instabilities and reorganize the
neutrino momentum distribution, in analogy to the superfluid instability of
fermions? We show that, for standard weak interactions, pairing instabilities can arise only in the presence of discontinuities in the occupation number, such as the sharp
Fermi surface responsible for superconductivity in metals. However, discretized energy spectra can mimic such discontinuities and artificially generate superfluid instabilities. These spurious instabilities disappear in the continuum limit.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-th
On the Validity of the Effective Theory of (Multi-)Field Inflation
Andrea Ambrosi de Magistris and Alberto Salvio
Motivated by trans-Planckian issues in inflation, we determine the
Hilbert space and amplitudes of
quantum perturbations in the general low-energy effective theory of (multi-)field inflation without relying on the sub-horizon limit. The scalar sector is the most intricate, featuring field mixings and second-class constraints, which we handle using Dirac brackets. These results enable us to estimate the magnitude of higher-derivative corrections. In the specific case of slow-roll inflation, such estimate can be expressed in terms of the first slow-roll parameter $\epsilon$ for a given cutoff $\Lambda$. We apply our results to several inflationary models with finite $\Lambda$:
Higgs inflation, the Starobinsky model, natural inflation and hilltop inflation.
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Astrophysics of Galaxies
BlackHoleWeather – Chaotic cold accretion across the meso-scale: Variability and kinematics
Filippo Barbani, Massimo Gaspari, Olmo Piana et al. (+12 more)
Accretion onto supermassive black holes (SMBHs) in realistic
halos is time-variable, governed by
turbulence, cooling, and multiphase condensation. In chaotic cold
accretion (CCA), clouds and filaments condense out of the hot gas and feed the SMBH stochastically. We investigate how
turbulence regulates the variability, radial transport, and kinematics of CCA, focusing on the meso-scale connecting
halo rain to inner inflow. We analyse 3D hydrodynamic simulations with a GPU-accelerated code, including cooling and driven subsonic
turbulence in a stratified
galaxy group, resolving scales from kpc to sub-pc and probing two turbulent weather regimes. In both regimes, SMBH
accretion proceeds through CCA, remains super-Bondi, and varies by up to $\sim 2$ dex. The runs diverge mainly at meso-scales: strong stirring sustains fragmented feeding and clear inflow enhancement at 0.1-1 kpc, whereas weaker
turbulence yields a smoother central cascade. Yet innermost feeding rates remain similar, implying SMBH
accretion is not directly supply-limited by macro-scale weather.
Accretion rate distributions peak at low Eddington ratios, indicating maintenance-mode state.
Accretion rate power spectra follow a broken power law, with pink noise on long/intermediate timescales and a steeper red-noise tail at high frequencies, consistent with parsec-scale collisional damping. CCA modes are captured by two complementary diagnostics: the $\mathcal{C}$-ratio ($\equiv t_{\rm cool}/t_{\rm eddy}$) $\approx 1$ identifies soft X-ray gas as the gateway of condensation, while the k-plot (line broadening vs. shift) shows that the weather distinction is strongest on meso-scales, where the stormy regime produces broader, overlapping multiphase kinematics than the rainy regime. The meso-scale bridges
halo rain and micro-scale CCA feeding, regulating spatial transport, kinematic imprint, and temporal coherence of SMBH growth.
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All authors Filippo Barbani, Massimo Gaspari, Olmo Piana, Vieri Cammelli, Fred J. Jennings, Davide M. Brustio, Giovanni Stel, Valeria Olivares, Filippo M. Maccagni, Martin Fournier, Francesco Tombesi, Pasquale Temi, Fabrizio Fiore, Roberto Serafinelli, Ashkbiz Danehkar
Astrophysics of Galaxies
BlackHoleWeather – Jet-regulated chaotic cold accretion across the meso scale: Morphology and thermodynamics
Vieri Cammelli, Massimo Gaspari, Olmo Piana et al. (+11 more)
How mechanical AGN feedback couples to multiphase condensation across scales remains a problem in
galaxy groups and clusters. It is unclear how jets reshape the chaotic cold
accretion (CCA) cycle and regulate black-hole fueling. BlackHoleWeather aims to build a unified description of the AGN
baryon cycle across horizon,
galactic, and group scales. Here we focus on how weather states shape the morphology and thermodynamics of jet-regulated CCA. We perform two hydrodynamical simulations of a turbulent, radiatively cooling
galaxy-group atmosphere with self-regulated AGN feedback. The runs are initialized in two
turbulence regimes and evolved with a kinetic mass-loaded jet. The jet prevents cooling via heating, but anisotropically reorganizes condensation through compression, entrainment, and turbulent mixing. In the stronger-
turbulence case, condensation starts later but becomes extended, filamentary, and mixed, with a broader hot-warm-cold bridge, a porous cocoon, and burst-dominated fueling. This run evolves toward a cloud-dominated state with inefficient central
accretion. In the weaker-
turbulence case, condensation starts earlier and remains coherent and centrally confined, yielding a regular cocoon, a longer-lived inner cold reservoir with sustained fueling. In both runs, condensation is suppressed inside the jet channel and survives in the surrounding atmosphere and along the jet-ambient interface. Once condensation begins, SMBH fueling becomes super-Bondi. These results extend CCA from a pure cooling +
turbulence problem to a jet-regulated weather process. Ambient
turbulence acts as a control parameter, producing an extended stormy phase, a centrally retained rainy cycle, and, in the high-
turbulence case, a later cloudy state with inefficient central fueling. The meso scale emerges as the layer linking
halo thermodynamics to SMBH feeding within the broader BlackHoleWeather framework.
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All authors Vieri Cammelli, Massimo Gaspari, Olmo Piana, Filippo Barbani, Giovanni Stel, Davide M. Brustio, Valeria Olivares, Francesco Salvestrini, Ashkbiz Danehkar, Michael Reefe, Pasquale Temi, Filippo M. Maccagni, Francesco Tombesi, Martin Fournier
Astrophysics of Galaxies
BlackHoleWeather – Spin-coupled chaotic cold accretion across the meso-scale: Morphology and thermodynamics
Olmo Piana, Massimo Gaspari, Filippo Barbani et al. (+10 more)
Supermassive black hole (SMBH)
spin is a key but poorly constrained ingredient of the feeding-feedback loop. Chaotic cold
accretion (CCA) of cold gas clouds delivers rapidly varying three-dimensional torques that drive
spin evolution and jet-axis reorientation, and in turn
spin regulates jet power. We introduce a time-dependent SMBH
spin model linking resolved multiphase feeding at meso scales to unresolved relativistic angular-momentum transfer at the innermost stable circular orbit (ISCO). We perform GPU-accelerated hydrodynamical simulations of a group atmosphere with jet feedback and SMBH
spin evolution, resolving multiphase inflow and angular-momentum direction below parsec scales. We compare fixed-axis, direct, and hybrid prescriptions, with the latter preserving the resolved torque direction while filtering its magnitude through a Kerr ISCO closure. We then apply the hybrid model to low- and high-
turbulence group setups. The cold-gas reservoir is nearly independent of whether the jet is fixed,
spin-coupled, or rapidly reorienting. The
spin prescription instead controls the inner feeding-feedback coupling, modulating central
accretion, jet efficiency, and feedback geometry. The hybrid model is bracketed by analytic limits, whereas the direct model overestimates
spin variability and jet-axis wandering, showing that an ISCO closure is required. Low-
spin SMBHs are easier to reorient because a misaligned torque acts on a smaller angular-momentum reservoir. The decisive quantity is the coherence of the delivered angular momentum: the low-
turbulence run preserves longer feeding bridges and faster
spin evolution, whereas stronger
turbulence fragments the inflow and enhances torque cancellation. In CCA,
turbulence regulates whether the cold reservoir remains connected, how the angular momentum reaches the SMBH, where the next jet points, and how feedback is imprinted onto the
halo.
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All authors Olmo Piana, Massimo Gaspari, Filippo Barbani, Vieri Cammelli, Giovanni Stel, Davide M. Brustio, Valeria Olivares, Francesco Salvestrini, Ashkbiz Danehkar, Francesco Tombesi, Pasquale Temi, Filippo M. Maccagni, Martin Fournier