Earth and Planetary Astrophysics · Cross-listed from physics.geo-ph
Comparison of Australasian tektites with Australasian microtektites and BeLaU spherules recovered from the ocean
Eugenia Hyung, Emma Levy, Loralei Cook et al. (+4 more)
The Australasian strewn field covers more than 15% of Earth's surface, consisting of tektites and microtektites. Australasian tektites from Southeast Asia and Australia, as well as microtektites recovered from deep sea sediments and Antarctica, are established to be derived from upper continental crust sediments. An expedition to retrieve remnants of bolide CNEOS 2014 January 8 (IM1), held in the Pacific Ocean, was in proximity to the known extent of the Australasian strewn field, and yielded "BeLaU"-spherules, whose compositions did not match most well-studied
solar system material. We therefore report precise and comprehensive elemental data for Australasian tektites to compare their elemental abundances to those of microtektites from deep sea sediments, and BeLaU. Our findings corroborate previous studies that Australasian tektites and microtektites closely resemble the elemental abundance patterns of the upper continental crust. Meanwhile, the elemental patterns of the BeLaU-spherules are distinct from the Australasian tektite/microtektite compositions.
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All authors Eugenia Hyung, Emma Levy, Loralei Cook, Stein B. Jacobsen, Abraham Loeb, Jayden Squire, Juraj Farkas
Instrumentation and Methods for Astrophysics
Trade-off Analysis for Lunar Augmented Navigation Service (LANS) Constellation Design
Keidai Iiyama and Grace Gao
The establishment of a sustainable human presence on the Moon demands robust positioning,
navigation, and timing (PNT) services capable of supporting both surface and orbital operations. This paper presents a comprehensive trade-off analysis of lunar frozen-orbit constellations for the Lunar Augmented
Navigation Service (LANS), focusing on how the number of satellites and orbital parameters influence coverage, position dilution of precision (PDOP), orbit determination accuracy, receiver noise, and orbit insertion cost. Three Walker-constellation families based on frozen elliptical and circular orbits are examined to characterize their relative advantages across different semi-major axes and inclinations. Results show that larger semi-major axes enhance both polar and global coverage, though the optimal inclination depends on the constellation type and target service region. The south elliptical lunar frozen orbit (ELFO) Walker constellation provides superior performance for polar coverage and PDOP, whereas the circular lunar frozen orbit (CLFO) Walker configuration achieves the best global uniformity. Orbit determination errors and receiver noise both increase with larger semi-major axes and higher inclinations, reflecting weaker
geometric observability and reduced received signal power at apolune for eccentric orbits. Orbit insertion analysis reveals clear trade-offs among transfer duration, characteristic energy ($C_3$) at trans-lunar injection, and insertion $\Delta V$: shorter transfers require higher insertion $\Delta V$, while low-energy transfers achieve smaller $\Delta V$ at the cost of months-long durations and higher $C_3$. These findings provide a systematic framework for designing LANS constellations for both regional and global coverage.
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Solar and Stellar Astrophysics
Breaking gyrochronology through the collapse of coronal winds
Michaël Lévesque and Paul Charbonneau
Gyrochronology, a method for dating aged field
stars ($\gtrsim$ a few Gyr) based on their rotation rate, has recently been shown to fail for many
stars older than the sun. The explanation most often put forth is that a shutdown or mode change in the
stellar dynamo leads to a sharp decrease in angular momentum loss in magnetized coronal winds. In this paper, we explore an alternate possibility, namely a collapse of the wind itself through a reduction of coronal heating. We show that in the low coronal temperature ($T_0$) limit, even at
solar-like low rotation rates ($\Omega$) and coronal
magnetic field strength ($B_{r0}$), magnetocentrifugal effects are important and preclude expression of the mass and angular momentum loss rates as power-laws of $T_0$ or $\Omega$ when $T_0$ drops below $\simeq 1.5\,$MK. Mass loss is found to scale linearly with power input into the wind at all coronal temperatures. Introducing an ad hoc power law relationship $T_0\propto B_{r0}^\sigma$ while retaining the “standard” dynamo relationship $B_{r0}\propto\Omega$, we show that reproducing the observed break in gyrochronology requires an exponent $\sigma\gtrsim 1.5$, with which is associated a drop by over 3 orders of magnitude in power input into the quiet corona. This appears physically unrealistic, given current observations of chromospheric and coronal non-thermal emission in aged
solar-type
stars.
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Astrophysics of Galaxies
Gabriele S. Ilha, C. M. Harrison, V. Mainieri et al. (+17 more)
AGN feedback is a well known mechanism in the
evolution of
galaxies. One open question is the driving mechanism of
galaxy-scale
outflows. At low
redshift,
radio jets often interact with the ISM, generating
turbulence and driving ionized
outflows. Despite this evidence at low
redshift, relatively few studies have investigated the
radio-ionized gas connection at
cosmic noon. Thus, our main goal is to conduct a pilot study using VLA data for three
quasars with moderate/high
radio power, which have ionized
outflows identified in observations from the SUPER survey. We used [OIII] data from SINFONI analyzed in earlier studies, along with new 6.2 GHz VLA
radio observations, at comparable spatial resolution. We also incorporate
radio data from the literature to explore the
radio emission. We detected extended
radio structure in our VLA A-array data for two
quasars. The extended structure in J1333+1649 aligns with the smaller-scale emission seen in archival images, suggesting a jet propagating from
nuclear to
galaxy-wide scales. In all three
quasars, we found that the brightest
radio emission and ionized gas have comparable spatial scales. Furthermore, the position angles of the
radio emission and ionized gas present small offsets for the two targets with extended structures. Given that the kinematics of the ionized gas in all three
quasars is dominated by
outflows, our results suggest a strong connection between
radio emission and ionized
outflows in typical AGN at
cosmic noon. Based on energetic considerations and comparisons with archival data,
radio jets could be a significant mechanism for driving
outflows in AGN from
cosmic noon to low
redshifts. However, with the exception of one object (J1333+1649), we cannot rule out the possibility that the
radio emission arises from shocks in the interstellar medium caused by disk winds or radiatively driven
outflows.
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All authors Gabriele S. Ilha, C. M. Harrison, V. Mainieri, Ann Njeri, E. Bertola, M. Bischetti, C. Circosta, C. Cicone, G. Cresci, V. A. Fawcett, A. Georgakakis, D. Kakkad, I. Lamperti, A. Marconi, M. Perna, A. Puglisi, D. Rosario, G. Tozzi, C. Vignali, G. Zamorani
Astrophysics of Galaxies
Analysis of Planetary Nebulae in the Milky Way: Physical Properties, Chemical Abundances, and Galactic Distributions
N. Erzincan, N. Aksaker, A. Akyuz et al. (+1 more)
In this study, we investigate the physical and chemical properties of planetary nebulae (PNe) from the Milky Way
Galaxy using the largest number of sources to date, with 1,449 True PNe from the HASH database. Among the
Galactic components thin disk, thick disk,
halo, and bulge-most PNe are concentrated in the
Galactic disk, with a median angular size of 12 arcseconds (0.45 pc), while
halo PNe tend to have larger sizes. Physical parameters of whole PNe, extinction coefficent c(Hbeta), electron temperature (Te), and density (Ne) show Gaussian-like distributions with medians of 1.5, 9,900 K, and 1,200 cm(-3), respectively. The abundances of He, N, O, Ne, S, Cl, and Ar in PNe show Gaussian distributions with slight variations across
Galactic components. PNe located in thin disk exhibit higher abundances, except for O and Ne, while PNe in
halo have the lowest values for all elements. Strong correlations between elements, particularly Sulphur vs. Nitrogen (r=0.87), were identified using statistical tests. Comparisons with previous studies reveal variations ( 2 dex.) in abundance ratios, particularly in
halo PNe. We also present the first detailed database in the literature, providing 7,200 abundance values for these elements, derived from 16,500 emission line measurements, to support the testing and development of theoretical models.
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All authors N. Erzincan, N. Aksaker, A. Akyuz, Q. Parker
Cosmology and Nongalactic Astrophysics
Probing cosmic velocities with the pairwise kinematic Sunyaev-Zel'dovich signal in DESI Bright Galaxy Sample DR1 and ACT DR6
B. Hadzhiyska, Y. Gong, Y. Hsu et al. (+55 more)
We present a measurement of the pairwise kinematic Sunyaev-Zel'dovich (kSZ) signal using the Dark Energy Spectroscopic Instrument (DESI) Bright
Galaxy Sample (BGS) Data Release 1 (DR1)
galaxy sample overlapping with the Atacama Cosmology
Telescope (ACT) CMB temperature map. Our analysis makes use of $1.6$ million
galaxies with
stellar masses $\log M_\star/M_\odot > 10$, and we explore measurements across a range of aperture sizes ($2.1' < \theta_{\rm ap} < 3.5'$) and
stellar mass selections. This statistic directly probes the velocity field of the large-scale structure, a unique observable of
cosmic dynamics and modified
gravity. In particular, at low
redshifts, this quantity is especially interesting, as deviations from General Relativity are expected to be largest. Notably, our result represents the highest-significance low-
redshift ($z \sim 0.3$) detection of the kSZ pairwise effect yet. In our most optimal configuration ($\theta_{\rm ap} = 3.3'$, $\log M_\star > 11$), we achieve a $5\sigma$ detection. Assuming that an estimate of the optical depth and
galaxy bias of the sample exists via e.g., external observables, this measurement constrains the fundamental cosmological combination $H_0 f \sigma_8^2$. A key challenge is the degeneracy with the
galaxy optical depth. We address this by combining CMB
lensing, which allows us to infer the
halo mass and
galaxy population properties, with hydrodynamical simulation estimates of the mean optical depth, $\bar \tau$. We stress that this is a proof-of-concept analysis; with BGS DR2 data we expect to improve the statistical precision by roughly a factor of two, paving the way toward robust tests of modified
gravity with kSZ-informed velocity-field measurements at low
redshift.
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All authors B. Hadzhiyska, Y. Gong, Y. Hsu, P. A. Gallardo, J. Aguilar, S. Ahlen, D. Alonso, R. Bean, D. Bianchi, D. Brooks, F. J. Castander, T. Claybaugh, S. Cole, A. Cuceu, A. de la Macorra, Arjun Dey, S. Ferraro, A. Font-Ribera, J. E. Forero-Romero, S. Gontcho A Gontcho, G. Gutierrez, J. Guy, H. K. Herrera-Alcantar, C. Howlett, D. Huterer, M. Ishak, R. Joyce, T. Kisner, A. Kremin, M. Landriau, L. Le Guillou, M. E. Levi, M. Manera, A. Meisner, R. Miquel, K. Moodley, T. Mroczkowski, S. Nadathur, N. Palanque-Delabrouille, W. J. Percival, F. Prada, F. J. Qu, I. Perez-Rafols, B. Ried Guachalla, G. Rossi, E. Sanchez, E. Schaan, D. Schlegel, M. Schubnell, H. Seo, C. Sifon, J. Silber, D. Sprayberry, G. Tarle, E. M. Vavagiakis, B. A. Weaver, R. Zhou, H. Zou
High Energy Astrophysical Phenomena
The 2025 Failed Outburst of IGR J17091-3624: Spectral Evolution and the Role of Ionized Absorbers
Oluwashina K. Adegoke, Javier A. Garcia, Guglielmo Mastroserio et al. (+15 more)
IGR J17091-3624 is the only black hole X-ray binary candidate, aside from the well-studied black hole system GRS 1915+105, observed to exhibit a wide range of structured variability patterns in its light curves. In 2025, the source underwent a “failed” outburst: it brightened in the hard state but did not transition to the soft state before returning to quiescence within a few weeks. During this period, IGR J17091-3624 was observed by multiple ground- and space-based facilities. Here, we present results from six pointed NuSTAR observations obtained during the outburst. None of the NuSTAR light curves showed the exotic variability classes typical of the soft state in this source; however, we detected, for the first time, strong dips in the count rate during one epoch, with a total duration of $\sim4\,\mathrm{ks}$ as seen by NuSTAR. Through spectral and timing analysis of all six epochs, we investigate the hard-state spectral
evolution and the nature of the dips. A clear
evolution of the coronal properties with luminosity is observed over all six epochs, with clear signatures of relativistic disk reflection which remain largely unchanged across the first five epochs. The first five epochs also show a strong and stable quasi-periodic oscillation (QPO) feature in the power spectra. The dips observed in Epoch 5 are consistent with partial obscuration by ionized material with a column density $N_{\mathrm{H}} \approx 2.0 \times 10^{23}\,\mathrm{cm^{-2}}$. We discuss possible origins for this material and place constraints on the orbital parameters and distance of the system.
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All authors Oluwashina K. Adegoke, Javier A. Garcia, Guglielmo Mastroserio, Elias Kammoun, Riley M. T. Connors, James F. Steiner, Fiona A. Harrison, Douglas J. K. Buisson, Joel B. coley, Benjamin M. Coughenour, Thomas Dauser, Melissa Ewing, Adam Ingram, Erin Kara, Edward Nathan, Maxime Parra, Daniel Stern, John A. Tomsick
Earth and Planetary Astrophysics
A formation mechanism for narrow rings around minor bodies
C. Beaugé, E. Gianuzzi, N. Trógolo et al. (+3 more)
The recent discovery of narrow rings around minor bodies has raised many questions regarding their origin and current dynamics. Sharp ring boundaries seem indicative of shepherding moonlets, but none have been found. All rings lie close to
spin-orbit resonances (SORs) with the central body, particularly the 1/3, even though it is not clear how these may be related. Furthermore, in at least one case the location of the ring is exterior to the Roche radius, adding to the striking differences with respect to
giant planets. We study the dynamical
evolution of a particle disk around a minor body, perturbed by the non-spherical component of the
gravity field, particle collisions, and
spin changes of the central mass linked to angular momentum conservation. By varying key parameters, we search for cases where the combined effects may lead to resonance capture and orbital configurations similar to those that have been observed. We performed N-body simulations of massless particles orbiting a central spherical body with a co-rotating mass anomaly. Collisions were modeled by adopting a simple radial damping force. Angular momentum conservation links the body
spin to the disk orbital
evolution. Since the gravitational effect of the test particles is neglected, this back-reaction is introduced externally assuming ad hoc
spin-down rates and disk mass. Interaction between non-sphericity and collisions leads to the formation of a narrow ring that slowly recedes from the central mass.
Spin-down of the minor
planet shifts the SORs outward, enabling resonant capture. For suitable parameters, a portion -or all- of the initial disk can become trapped in the 1/3 SOR with the mass anomaly, in dynamically stable low-eccentricity orbits. Although the required disk mass is high ($\ge 1\%$ of the central body), long-term collisional erosion could reduce it to values that are consistent with observed ringlets.
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All authors C. Beaugé, E. Gianuzzi, N. Trógolo, A. M. Leiva, F. A. Zoppetti, M. Cerioni
High Energy Astrophysical Phenomena
Axisymmetric hydrodynamics in numerical relativity: treating coordinate singularity, artificial heating and modeling MHD instabilities
Pavan Chawhan, Matthew D. Duez, Francois Foucart et al. (+2 more)
Two-dimensional axisymmetric simulations of binary
neutron star (BNS) merger remnant are a cheap alternative to 3D simulations. To maintain realism for secular timescales, simulations must avoid accumulated errors from drifts in conserved quantities and artificial heating, and they must model turbulent transport in a way that remains plausible throughout the
evolution. It is also crucial to avoid numerical artifacts due to the polar coordinate axis singularity. Methods that behave well near the axis often break flux-conservative form of the hydrodynamic equations, resulting in significant drifts in conserved quantities. We present a flux-conservative scheme that maintains smoothness near the axis without sacrificing conservative formulation of the equations or incurring drifts in conserved global quantities. We compare the numerical performance of different treatments of the hydrodynamic equations when evolving a hypermassive
neutron star resembling the remnant of a BNS merger. These simulations demonstrate that the new scheme combines the axis smoothness of non-conservative methods with the mass and angular momentum conservation of other conservative methods on $\sim$ $10^2$ ms timescales of viscous and
neutrino-driven
evolution. Because fluid profiles remain smooth in the remnant interior, it is possible to remove artificial heating by evolving the
entropy density. We show how physical heating and cooling terms can be easily calculated from source terms of the conservative
evolution variables and demonstrate our implementation. Finally, we discuss and implement improvements to the effective viscosity scheme to better model the effect of magnetohydrodynamic instabilities as the remnant evolves.
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All authors Pavan Chawhan, Matthew D. Duez, Francois Foucart, Patrick Chi-Kit Cheong, Nishad Muhammed
Instrumentation and Methods for Astrophysics
Extracting latent representations from X-ray spectra. Classification, regression, and accretion signatures of Chandra sources
Nicolò Oreste Pinciroli Vago, Juan Rafael Martínez-Galarza and Roberta Amato
Spectral signatures are crucial in the era of large X-ray surveys. Automatic machine learning methods have proven useful in this respect, but so far they have not been applied to large spectral
datasets, such as the Chandra Source Catalog (CSC). This work aims to develop a compact and physically meaningful representation of Chandra X-ray spectra using deep learning. To verify that the learned representation captures relevant information, we evaluate it through classification, regression, and interpretability analyses, and measure the mutual information between spectral and time-domain properties of these sources, aiding in the future identification of transient events. We use a
transformer-based autoencoder to compress X-ray spectra into representations in an 8-dimensional latent space. Astrophysical source types and physical summary statistics are compiled from external catalogs. We evaluate the learned representation in terms of spectral reconstruction accuracy, clustering performance on 8 known astrophysical source classes, and correlation with physical quantities such as hardness ratios and hydrogen column densities ($N_H$). Upon reconstruction, clustering in the latent space yields a balanced classification accuracy of $\sim$40% across the 8 source classes, increasing to $\sim$69% when restricted to AGNs and
stellar-mass compact objects exclusively. Moreover, latent features correlate with spectral and temporal properties, suggesting that the compressed representation captures physically relevant information. Features learned directly from X-ray spectra capture relevant physical information as effectively as human-extracted features that require additional computations. They can be used for both classification and regression in large surveys, and also share mutual information with time-domain properties. The method can be adapted to existing and upcoming X-ray catalogs.
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Cosmology and Nongalactic Astrophysics
Field-level likelihood for projected fields: Evolved projected fields from initial projected fields
Kevin Hong, Rugved Pund and Anže Slosar
The evolved cosmological matter density field is fully determined by the initial matter density field at fixed cosmological parameters. However, the two-dimensional cosmological projected matter density field, relevant for weak-
lensing and photometric
galaxy studies, is fully determined by the initial projected matter density field only at the linear order. At non-linear order, the entire volume of initial matter contributes. We study a model for the evolved projected density field that is deterministic in the initial projected density fields and probabilistic in the effects of the remaining modes in the initial conditions. We write down predictions for the mean evolved projected field model using Lagrangian perturbation theory. We run a suite of small $N$-body simulations with fixed projected initial conditions and measure the statistical properties of the ensemble of evolved projected fields. Measurements and theory are in good agreement and show that the information on the initial projected fields is exponentially suppressed on non-linear scales. We implement this approach in a likelihood code and use
Hamiltonian Monte-Carlo sampling to show that initial fields can be reconstructed even in the presence of non-trival mask features.
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Earth and Planetary Astrophysics
NGTS-11 c: a transiting Neptune-mass planet interior to the warm Saturn NGTS-11 b
David R. Anderson, Jose I. Vines, Katharine Hesse et al. (+56 more)
We report the discovery of NGTS-11 c, a transiting warm Neptune ($P \approx 12.8$ d; $M_{p} = 1.2^{+0.3}_{-0.2} M_{\mathrm{Nep}}$; $R_{p} = 1.24 \pm 0.03 R_{\mathrm{Nep}}$), in an orbit interior to the previously reported transiting warm Saturn NGTS-11 b ($P \approx 35.5$ d). We also find evidence of a third outer companion orbiting the K-
dwarf NGTS-11. We first detected transits of NGTS-11 c in TESS light curves and confirmed them with follow-up transits from NGTS and many other ground-based facilities. Radial-velocity monitoring with the HARPS and FEROS spectrographs revealed the mass of NGTS-11 c and provides evidence for a long-period companion ($P > 2300$ d; $M_{p} \sin i > 3.6 M_{\mathrm{Jup}}$). Taking into account the two additional bodies in our expanded
datasets, we find that the mass of NGTS-11 b ($M_{p} = 0.63 \pm 0.09 M_{\mathrm{Sat}}$; $R_{p} = 0.97 \pm 0.02 R_{\mathrm{Sat}}$) is lower than previously reported ($M_{p} = 1.2 \pm 0.3 M_{\mathrm{Sat}}$). Given their near-circular and compact orbits, NGTS-11 c and b are unlikely to have reached their present locations via high-eccentricity migration. Instead, they probably either formed in situ or formed farther out and then underwent disk migration. A comparison of NGTS-11 with the eight other known systems hosting multiple well-characterized warm
giants shows that it is most similar to Kepler-56. Finally, we find that the commonly used 10-day boundary between hot and warm Jupiters is empirically well supported.
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All authors David R. Anderson, Jose I. Vines, Katharine Hesse, Louise Dyregaard Nielsen, Rafael Brahm, Maximiliano Moyano, Peter J. Wheatley, Khalid Barkaoui, Allyson Bieryla, Matthew R. Burleigh, Ryan Cloutier, Karen A. Collins, Phil Evans, Steve B. Howell, John Kielkopf, Pablo Lewin, Richard P. Schwarz, Avi Shporer, Thiam-Guan Tan, Mathilde Timmermans, Amaury H. M. J. Triaud, Carl Ziegler, Ioannis Apergis, David J. Armstrong, Douglas R. Alves, Daniel Bayliss, Francois Bouchy, Sarah L. Casewell, Alexander Chaushev, Benjamin D. R. Davies, Tansu Daylan, Elsa Ducrot, Mourad Ghachoui, Samuel Gill, Edward Gillen, Michael Gillon, Maximilian N. Gunther, Thomas Henning, Melissa Hobson, Keith Horne, Emmanuel Jehin, James S. Jenkins, Andres Jordan, Michelle Kunimoto, Regis Lachaume, Monika Lendl, James McCormac, Felipe Murgas, Catriona Murray, Ares Osborn, Francisco J. Pozuelos, Didier Queloz, Suman Saha, Daniel Sebastian, Alexis M. S. Smith, Stephane Udry, Solène Ulmer-Moll, Andrew Vanderburg, Richard G. West
Cosmology and Nongalactic Astrophysics
Probing Helium Reionization Through the $^{3}\mathrm{He}^{+}$ Hyperfine Transition Line
Arghyadeep Basu, Benedetta Ciardi and Enrico Garaldi
We investigate the hyperfine transition of $^{3}\mathrm{He}^{+}$ as a promising probe of the IGM during the final stages of helium reionization. Utilising the most recent helium reionization simulation, we generate three-dimensional maps of the 3.5cm ($8.67$,GHz) differential brightness temperature and analyze its
evolution. Our `fiducial' results show that the volume-averaged brightness temperature declines rapidly from $\sim 10^{-2}\,\mu\mathrm{K}$ (in the `optimistic' approach, i.e. $T_{\rm s} = T_{\rm gas}$, $\sim 1,\mu\mathrm{K}$) at $z = 3$ to $\sim 8 \times 10^{-5},\mu\mathrm{K}$ ($\sim 2.5 \times 10^{-3},\mu\mathrm{K}$) by $z = 2.3$, tracing the He,ii to He,iii transition driven by
quasars. The power spectrum of the 3.5cm signal exhibits a scale-dependent
evolution, peaking on small scales and declining as reionization progresses. We explore the cross-correlation of the 3.5cm transition line with the distribution of AGNs, which shows a transition from positive to negative correlation as ionized regions grow. Although current observational upper limits lie several orders of magnitude above theoretical predictions, future
radio arrays such as SKA-mid offer promising prospects. Overall, this study highlights the $^{3}\mathrm{He}^{+}$ hyperfine transition as a sensitive tracer of the thermal and ionization history of the IGM during helium reionization. The predicted signal is also subject to additional uncertainty from
spin temperature modelling, and the true amplitude is expected to lie between the limiting cases explored in this work.
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High Energy Astrophysical Phenomena
Exploring the impact of electromagnetic dissipation on ultra-relativistic plasma outflows
Argyrios Loules and Nektarios Vlahakis
Ultra-relativistic
plasma outflows are intrinsically connected with gamma-ray bursts. Over the years, a large number of analytical and numerical works has been devoted to understanding the intricacies of their complex dynamics, with most of these past studies performed in the ideal MHD regime. We propose a self-similar formalism, based on the expansion of the equations of resistive relativistic magnetohydrodynamics, for the description of these
outflows in the vicinity of their
symmetry axis and present semi-analytical solutions describing strongly relativistic jets in both the ideal and resistive MHD regimes. Our solutions provide a clear picture of the impact of electromagnetic dissipation on the acceleration and collimation mechanisms which determine the kinetic and morphological characteristics of these relativistic
outflows. The resistive MHD solutions are compared to their ideal MHD counterparts, revealing the key differences between the two regimes. Our comparative analysis sheds light on the possible role of electromagnetic dissipation in shaping the dynamics of the ultra-relativistic
outflows associated with gamma-ray bursts.
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High Energy Astrophysical Phenomena
Investigating Nonlinear Landau Damping in Hybrid Simulations
Benedikt Schroer, Damiano Caprioli and Pasquale Blasi
Phenomenological studies of
cosmic-ray self-confinement often hinge on the linear theory for the growth rate of the streaming instability and for the damping rate of the generated
magnetic modes. Largely different expressions exist, especially for the rate of nonlinear Landau damping, which is often assumed to be the most important damping mechanism in warm ionized
plasmas. Using hybrid-PIC simulations in the resonant streaming instability regime, we present a comprehensive assessment of nonlinear Landau damping and show that the damping rate at a given scale depends on the power in
magnetic fields on larger scales. Furthermore, we find that an inverse cascade develops, which produces
magnetic fields on scales larger than the resonant ones. Here we extend previous results obtained for a mono-energetic distribution of non-thermal particles to the case of broader CR distributions, as a first step towards developing phenomenological models. Pre-existing
turbulence of Alfvénic nature at large scales severely affects the damping of waves produced by low-energy CRs; depending on its amplitude, such a
turbulence may inhibit the growth of streaming instability so that CRs are either self-confined at all energies or not at all.
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Solar and Stellar Astrophysics
Conversion and Damping of Nonaxisymmetric Internal Gravity Waves in Magnetized Stellar Cores
Cy S. David, Daniel Lecoanet and Pascale Garaud
Magnetism is thought to play an important role in the
evolution and dynamics of
stars, though little is known about
magnetic fields deep within
stellar interiors. A promising avenue for probing these fields uses asteroseismic observations of global oscillations that result from the coupling of acoustic waves in the convective zone to internal
gravity waves (IGWs) in the radiative interior. Recent modeling efforts implicate deep
magnetic fields in the suppression of dipole mixed modes observed in 20% of red
giants and a number of high-mass main sequence
stars. Previous numerical and theoretical work shows that core
magnetic fields could suppress axisymmetric global modes by refracting down-going IGWs into slow-magnetosonic (SM) waves that damp at
magnetic cutoff heights. Here, we extend these results to the nonaxisymmetric case, for which the IGWs and SM waves are coupled to a continuous spectrum of Alfven waves (AWs). We consider a Cartesian model of the radiative interior with uniform stratification and a spatially-varying, current-free
magnetic field. Using a Wentzel-Kramers-Brillouin approximation to solve for the vertical mode structure, corroborated with numerical simulations, we show that IGWs convert to up-going SM waves, which resonate with the Alfven spectrum and produce mixed SM-AW modes. We find cutoff heights (as in the axisymmetric case), above which the SM/SM-AWs convert to AWs. Latitudinal variations of the background
magnetic field lead to phase mixing of the AWs, resulting in rapid damping. Our results suggest that energy in both axisymmetric and nonaxisymmetric IGWs is lost via interactions with a strong
magnetic field.
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Solar and Stellar Astrophysics
Anatomy of the Class I protostar L1489 IRS with NOEMA - II. A disk replenished by a massive streamer
M. Tanious, R. Le Gal, A. Faure et al. (+3 more)
(abridged) Streamers are newly identified channels that transport mass from large, molecular-cloud scales down to small, protoplanetary-disk scales. To better understand their impact on
planet formation, it is essential to study their physical and chemical properties. In this framework, we aim to characterize the longest streamer identified in carbon chain emission within the Class I system L1489 IRS, connecting the nearby prestellar core L1489 to the young
stellar object (YSO). We observed multiple transitions of C$_2$H, ortho-c-C$_3$H$_2$, and HC$_3$N in L1489 IRS with NOEMA and IRAM-30m at 3mm and 2mm. Using a variety of radiative transfer methods, including a hyperfine structure (HFS) fitting, rotational diagrams, and proposing a new self-consistent Markov chain Monte Carlo (MCMC) approach combined with the non-LTE RADEX code, we derived the column densities and abundances of those molecules, as well as the H$_2$ number density along the streamer. This enabled us to estimate its mass, infall rate, and its impact on the {
star+disk} system's mass. We found lower limits on the streamer mass of $\geq(4.67-18.3)\times10^{-3}$ $M_\odot$ (i.e., $\geq0.65-2.57$ times the current disk mass) and an infall rate of $\geq(1.94-7.57)\times10^{-7}$ $M_\odot$ yr$^{-1}$, where the ranges correspond to the different molecular tracers. These values are consistent with those derived in similar Class I objects. This suggests that the disk could be fully replenished by streamer material. Given its mass, the streamer is likely at the origin of the external warped disk seen in this system, as predicted by numerical simulations. Moreover, the first investigations based on the C$_2$H/c-C$_3$H$_2$ and HC$_3$N/c-C$_3$H$_2$ abundance ratios suggest that the streamer chemistry may be inherited from the core. These results suggest, for the first time, that the chemical composition of a Class I object is [...]
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All authors M. Tanious, R. Le Gal, A. Faure, S. Maret, A. López-Sepulcre, P. Hily-Blant
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Quantum Damping of Cosmological Shear: A New Prediction from Loop Quantum Cosmologies
Wen-Cong Gan, Leila L. Graef, Rudnei O. Ramos et al. (+2 more)
We study the dynamics of the Bianchi I universe in modified loop
quantum cosmology (mLQC-I) and uncover a robust mechanism for isotropization: the shear is dynamically suppressed after the bounce and decays rapidly in the
quantum post-bounce regime, independently of the equation of state of standard matter sources. This naturally drives the Universe toward a homogeneous and isotropic expanding phase without fine-tuning. Our results show that mLQC-I provides a new
quantum-gravitational mechanism for suppressing anisotropies, absent in other bounce models.
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All authors Wen-Cong Gan, Leila L. Graef, Rudnei O. Ramos, Gustavo S. Vicente, Anzhong Wang
Instrumentation and Methods for Astrophysics
Dynamic SBI: Round-free Sequential Simulation-Based Inference with Adaptive Datasets
Huifang Lyu, James Alvey, Noemi Anau Montel et al. (+2 more)
Simulation-based inference (SBI) is emerging as a new statistical paradigm for addressing complex scientific inference problems. By leveraging the representational power of deep neural networks, SBI can extract the most informative simulation features for the parameters of interest. Sequential SBI methods extend this approach by iteratively steering the simulation process towards the most relevant regions of parameter space. This is typically implemented through an algorithmic structure, in which simulation and network training alternate over multiple rounds. This strategy is particularly well suited for high-precision inference in high-dimensional settings, which are commonplace in physics applications with growing data volumes and increasing model fidelity. Here, we introduce dynamic SBI, which implements the core ideas of sequential methods in a round-free, asynchronous, and highly parallelisable manner. At its core is an adaptive
dataset that is iteratively transformed during inference to resemble the target observation. Simulation and training proceed in parallel: trained networks are used both to filter out simulations incompatible with the data and to propose new, more promising ones. Compared to round-based sequential methods, this asynchronous structure can significantly reduce simulation costs and training overhead. We demonstrate that dynamic SBI achieves significant improvements in simulation and training efficiency while maintaining inference performance. We further validate our framework on two challenging astrophysical inference tasks: characterising the
stochastic gravitational wave background and analysing strong gravitational
lensing systems. Overall, this work presents a flexible and efficient new paradigm for sequential SBI.
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All authors Huifang Lyu, James Alvey, Noemi Anau Montel, Mauro Pieroni, Christoph Weniger
Astrophysics of Galaxies
The Nephele ecosystem: stars, globular clusters, and stellar streams associated with the progenitor galaxy of $\omega$ Centauri
G. Pagnini, P. Di Matteo, M. Haywood et al. (+7 more)
Globular clusters (GCs) and their associated
stellar streams are key tracers of the hierarchical assembly history of the Milky Way. $\omega$ Centauri, the most massive and chemically complex GC in the
Galaxy, is widely believed to be the remnant
nucleus of an accreted
dwarf galaxy. Identifying its associated debris and that of chemically similar clusters can provide important constraints on the nature of this progenitor system. We aim to identify field
stars that are chemically and kinematically linked to $\omega$ Cen and to a group of globular clusters associated with the Nephele
accretion event. We analyse APOGEE DR17 data using a Gaussian Mixture Model (GMM) in a 8-dimensional chemical space to identify field
stars whose abundances match those of $\omega$ Cen. We then compute the orbital energy and angular momentum of these
stars and apply a second GMM, calibrated on simulations from the e-TidalGCs project, to determine kinematic compatibility with the predicted streams of $\omega$ Cen and the associated Nephele GCs. We identify 470
stars chemically compatible with $\omega$ Cen, of which 58 are also Al-rich, consistent with second-generation
stars found in GCs. Of these, 6
stars show kinematics consistent with the predicted $\omega$ Cen stream, and additional
stars are linked to the
tidal streams of NGC 6205, NGC 6254, NGC 6273, NGC 6656, and NGC 6809. We also find overlap in chemical and kinematic properties between Nephele
stars and the
Gaia Sausage-Enceladus population. Our findings indicate
stellar debris linked to $\omega$ Cen and its candidate globular cluster family, consistent with a shared, now-disrupted
galactic progenitor. Despite residual uncertainties from disc contamination and limited sky coverage, the results demonstrate the effectiveness of combined chemical and dynamical analyses in uncovering relics of past
accretion events in the inner
Galaxy.
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All authors G. Pagnini, P. Di Matteo, M. Haywood, P. Bianchini, S. Ferrone, A. Mastrobuono-Battisti, O. Agertz, S. Khoperskov, F. Renaud, N. Ryde
Astrophysics of Galaxies
The THESAN-ZOOM project: The Hidden Neighbours of OI Absorbers during Reionization
Giulia Pruto, Laura Keating, Rahul Kannan et al. (+9 more)
Metal absorbers represent a powerful probe of
galaxy feedback and reionization, as highlighted by both observational and theoretical results showing an increased abundance of low-ionised metal species at higher
redshifts. The origin of such absorbers is currently largely unknown because of the low number of
galaxy counterparts detected, suggesting that they might be surrounded by low-mass faint sources below the current detection threshold. We use the THESAN-ZOOM radiation hydrodynamic simulations to investigate the connection between properties of neutral oxygen (OI) absorbers and
galaxies across
redshift $z = 5 - 8$. We find that the virialised gas in
haloes becomes progressively ionised with
cosmic time, leading to a decrease of $\approx 0.2$ in the covering fraction of neutral oxygen, while the total oxygen covering fraction remains constant. Comparing the OI line density obtained from our covering fractions with the trend suggested by blind
quasar observations, we determine that the observable absorbers ($N_{\rm OI} \gtrsim 10^{13}\,\text{cm}^{-2}$) are not confined to
haloes: at $z \geq 5$ the majority ($\gtrsim 60\%$) arise beyond $R_{\rm{vir}}$, consistent with recent JWST results. Close to OI absorbers, low-mass
galaxies ($M_\star \leq 10^8\,\rm{M}_\odot$) are more commonly found, while, depending on the simulated environment, we do not exclude the possibility of nearby more massive
star-forming sources ($\geq 5\,\text{M}_\odot\,\text{yr}^{-1}$) similar to those suggested by the latest ALMA observations. These results establish OI absorbers as sensitive tracers of the evolving ionisation structure around faint
galaxies to be probed by forthcoming deep spectroscopic surveys.
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All authors Giulia Pruto, Laura Keating, Rahul Kannan, Ewald Puchwein, Aaron Smith, Josh Borrow, Enrico Garaldi, Mark Vogelsberger, Oliver Zier, William McClymont, Xuejian Shen, Sandro Tacchella
Astrophysics of Galaxies
The ASTRID Simulation at z=0: From Massive Black Holes to Large-scale Structure
Yihao Zhou, Tiziana Di Matteo, Simeon Bird et al. (+7 more)
We present the $z=0$ results for the cosmological simulation ASTRID. Hosting $2\times 5500^3\approx$ 0.33 trillion particles in a box of $370\, {\rm Mpc}$ per side, ASTRID is one of the largest cosmological hydrodynamic simulations evolved to $z=0$. ASTRID features a large population of massive black holes (MBHs), covering a wide mass range $4\times10^{4}\sim 2\times 10^{11}\ M_{\odot}$. The adopted dynamical friction model provides a relatively accurate description of MBH dynamics, making ASTRID a powerful tool to study MBH growth and mergers in a cosmological context. ASTRID successfully captures the co-
evolution of MBHs and their host
galaxies, producing $M_{\rm BH}-M_{\star}$ and $M_{\rm BH}-\sigma$ relations in good agreement with observations. Notably, ASTRID generates scatter in these relations that is more consistent with observations than previous simulations, indicating a more realistic MBH diversity. The
galaxy stellar mass function at $z=0$ is generally consistent with observational constraints. When
dust attenuation is applied, the
galaxy luminosity function also agrees well with observations, and the bimodality in
galaxy colors is reproduced as well. ASTRID hosts a large population of massive
galaxy groups and clusters: 7
halos have $M_{\rm 200c}>10^{15}\ M_{\odot}$, and 9709
halos have $M_{\rm 200c}>10^{13}\ M_{\odot}$. We quantify the
stellar mass content in these
halos, and find that the correlations between the
stellar and
halo mass match well with observational constraints. Finally, we present the $z=0$ power spectra of MBH and
galaxies, as well as their bias with respect to the matter power spectrum. We find that MBHs with $M_{\rm BH}\geq 10^{8}\ M_{\odot}$ and
galaxies with $M_{\star}\geq 10^{10.5}\ M_{\odot}$ serve as good tracers of large-scale structure.
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All authors Yihao Zhou, Tiziana Di Matteo, Simeon Bird, Rupert Croft, Yueying Ni, Yanhui Yang, Nianyi Chen, Patrick Lachance, Xiaowen Zhang, Fatemeh Hafezianzadeh
Earth and Planetary Astrophysics
Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. IV. Lens Mass and Distance Measurements
Sean K. Terry, Etienne Bachelet, Farzaneh Zohrabi et al. (+54 more)
As part of the
Galactic Bulge Time Domain Survey (GBTDS), the Nancy Grace Roman
Galactic Exoplanet Survey (RGES) will use microlensing to discover cold outer
planets and free-floating
planets unbound to
stars. NASA has established several science requirements for the GBTDS to ensure RGES success. A key advantage of RGES is Roman's high angular resolution, which will allow detection of flux from many host
stars. One requirement specifies that Roman must measure the masses and distances of 40% of detected
planet hosts with 20% precision or better. To test this, we simulated microlensing events toward the GBTDS fields and used Fisher
matrix analysis to estimate light curve parameter uncertainties. Combining these with Roman imaging observables (lens flux, relative lens-source proper motion), we estimated the achievable precision of lens mass and distance measurements. Using pyLIMASS, a publicly available code for estimating lens properties, we applied this analysis to 3,000 simulated events. Assuming the Cassan et al. (2012)
exoplanet mass function, we find that >40% of host
stars meet the required 20% precision threshold, confirming that the GBTDS can satisfy the mission requirement. We validated our approach by comparing our inferred lens masses and distances to empirical measurements from detailed image-constrained light curve modeling of historical microlensing events with Hubble and Keck follow-up imaging. Our results agree within roughly 1 sigma, demonstrating that both approaches yield consistent and reliable mass and distance estimates, and confirming the robustness of our simulations for Roman-era microlensing science.
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All authors Sean K. Terry, Etienne Bachelet, Farzaneh Zohrabi, Himanshu Verma, Alison Crisp, Macy Huston, Carissma McGee, Matthew Penny, Natasha S. Abrams, Michael D. Albrow, Jay Anderson, Fatemeh Bagheri, Jean-Phillipe Beaulieu, Andrea Bellini, David P. Bennett, Galen Bergsten, T. Dex Bhadra, Aparna Bhattacharya, Ian A. Bond, Valerio Bozza, Christopher Brandon, Sebastiano Calchi Novati, Sean Carey, Jessie Christiansen, William DeRocco, B. Scott Gaudi, Jon Hulberg, Stela Ishitani Silva, Sinclaire E. Jones, Eamonn Kerins, Somayeh Khakpash, Katarzyna Kruszynska, Casey Lam, Jessica R. Lu, Amber Malpas, Shota Miyazaki, Przemek Mroz, Arjun Murlidhar, David Nataf, Marz Newman, Greg Olmschenk, Rakek Poleski, Clement Ranc, Nicholas J. Rattenbury, Krzysztof Rybicki, Vito Saggese, Jennifer Sobeck, Keivan G. Stassun, Alexander P. Stephan, Rachel A. Street, Takahiro Sumi, Daisuke Suzuki, Aikaterini Vandorou, Meet Vyas, Jennifer C. Yee, Weicheng Zang, Keming Zhang
Cosmology and Nongalactic Astrophysics
Constraining Power of Wavelet vs. Power Spectrum Statistics for CMB Lensing and Weak Lensing with Learned Binning
Kyle Boone, Georgios Valogiannis, Marco Gatti et al. (+1 more)
We present forecasts for constraints on the matter density ($\Omega_m$) and the amplitude of matter density fluctuations at 8h$^{-1}$Mpc ($\sigma_8$) from CMB
lensing convergence maps and
galaxy weak
lensing convergence maps. For CMB
lensing convergence auto statistics, we compare the angular power spectra ($C_\ell$'s) to the wavelet scattering transform (WST) coefficients. For CMB
lensing convergence $\times$
galaxy weak
lensing convergence statistics, we compare the cross angular power spectra to wavelet phase harmonics (WPH). This work also serves as the first application of WST and WPH to these probes. For CMB
lensing convergence, we find that WST and $C_\ell$'s yield similar constraints in forecasts for all surveys considered in this work. When CMB
lensing convergence is crossed with
galaxy weak
lensing convergence projected from $\textit{Euclid}$ Data Release 2 (DR2), we find that WPH outperforms cross-$C_\ell$'s by factors between $2.2$ and $3.4$ for individual parameter constraints. To compare these different summary statistics, we develop a novel learned binning approach. This method compresses summary statistics while maintaining interpretability. We find this leads to improved constraints compared to more naive binning schemes for our wavelet-based statistics, but not for $C_\ell$'s. By learning the binning and measuring constraints on distinct data sets, our method is robust to overfitting by construction.
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All authors Kyle Boone, Georgios Valogiannis, Marco Gatti, Cora Dvorkin
High Energy Astrophysical Phenomena · Cross-listed from gr-qc
MHDuet : a high-order General Relativistic Radiation MHD code for CPU and GPU architectures
Carlos Palenzuela, Miguel Bezares, Steven Liebling et al. (+12 more)
We present MHDuet, an open source
evolution code for general relativistic magnetohydrodynamics with
neutrino transport. The code solves the full set of Einstein equations coupled to a relativistic, magnetized fluid with an M1
neutrino radiation scheme using advanced techniques, including adaptive mesh and large eddy simulation techniques, to achieve high accuracy. The Simflowny platform generates the code from a high-level specification of the computational system, producing code that runs with either the SAMRAI or AMReX infrastructure. The choice of AMReX enables compilation and execution on GPUs, running an order of magnitude faster than on CPUs at the node level. We validate the code against
benchmark tests, reproducing previous results obtained with the SAMRAI infrastructure, and demonstrate its capabilities with simulations of
neutron stars employing realistic tabulated equations of state. Resolution studies clearly demonstrate convergence faster than second order in the grid spacing. Scaling tests reveal excellent strong and weak scaling performance when running on GPUs. The goal of the code is to provide a powerful tool for studying the dynamics of compact objects within multi-messenger astrophysics.
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All authors Carlos Palenzuela, Miguel Bezares, Steven Liebling, Federico Schianchi, Julio Fernando Abalos, Ricard Aguilera-Miret, Carles Bona, Juan Antonio Carretero, Joan Massò, Matthew P. Smith, Kwabena Amponsah, Kacper Kornet, Borja Miñano, Shrey Pareek, Miren Radia
Cosmology and Nongalactic Astrophysics
Simulation budgeting for hybrid effective field theories
Alexa Bartlett, Joseph DeRose and Martin White
In this work, we forecast the number of, and requirements on, N-body simulations needed to train hybrid effective field theory (HEFT) emulators for a range of use cases, using a hybrid of HMcode and perturbation theory as a surrogate model. Our accuracy goals, determined with careful consideration of statistical and systematic uncertainties, are $1\%$ accurate in the high-likelihood range of cosmological parameters, and $2\%$ accurate over a broader parameter space volume for $k<1 h Mpc^{-1}$ and $z<3$. Focusing in part on the 8-parameter $w_0w_a$CDM+$m_\nu$ cosmological model, we find that $<225$ simulations are required to meet our error goals over our wide parameter space, including models with rapidly evolving dark energy, given our simulation and emulator recommendations. For a more restricted parameter space volume, as few as 80 simulations are sufficient. We additionally present simulation forecasts for example use cases, and make the code used in our analyses publicly available. These results offer practical guidance for efficient emulator design and simulation budgeting in future cosmological analyses.
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Astrophysics of Galaxies
Strong Evidence for Cosmic Ray-Supported $\sim$L$^{\ast}$ Galaxy Halos via X-ray & tSZ Constraints
Sam B. Ponnada, Philip F. Hopkins, Yue Samuel Lu et al. (+3 more)
Many state-of-the-art
galaxy simulations featuring traditional feedback modes have significant challenges producing enough extended soft X-ray ($\sim 0.5-2$ keV) emission at R $\sim 0.5-1$ R$_{\rm vir}$ observed around
galaxies with
stellar masses M$_{\rm \ast} \lesssim 10^{11} \rm M_\odot$, without violating
galaxy mass function constraints. Moreover, thermal Sunyaev-Zel'dovich (tSZ) measurements probing the thermal pressure of similar
galaxies indicate it is orders-of-magnitude lower than predictions from simple
halo hydrodynamics and many hydrodynamical simulations. We demonstrate that these constraints can be met congruously with a large non-thermal pressure contribution in the form of
cosmic rays (CRs) from SNe and/or AGN, which lowers the tSZ signal while CR
leptons produce plentiful soft X-rays via inverse Compton scattering of the CMB. The combination of these two observations is far more constraining on the pressure budget of
galactic halos than either alone – if these novel tSZ and X-ray observations are borne out by future studies, then taken together they reveal the strongest evidence for CR support in
halos to date. Conversely, it is very difficult to produce the extended X-rays via traditional thermal emission without increasing the overall thermal pressure and thus tSZ signal in tandem, making these tensions even worse. Finally, tSZ & X-rays together unlock a novel observational method to constrain
halo CR pressure relative to thermal pressure, with implications for CR transport parameters and AGN feedback energetics across various
galaxy mass scales. Taking the currently observed constraints at M$_{\rm halo} \sim 10^{\rm 12} \rm M_\odot$ imply the
halo CR pressure must at least be equal to the gas thermal pressure.
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All authors Sam B. Ponnada, Philip F. Hopkins, Yue Samuel Lu, Emily M. Silich, Iryna S. Butsky, Dusan Keres