Cosmology and Nongalactic Astrophysics
Nonlinear Information from DESI Luminous Red Galaxies: An Emulator-Based Analysis of Pre- and Post-Reconstruction Power Spectra
Yuting Wang, Gong-Bo Zhao, Kazuya Koyama et al. (+61 more)
We present joint measurements of the pre- and post-reconstruction power spectra, $P_{\rm pre}$ and $P_{\rm post}$, together with their cross-power spectrum, $P_{\rm cross}$, for the Luminous Red
Galaxies (LRGs) in the DESI Data Release 1 (DR1). We jointly analyse these observables with an emulator-based full-shape modeling framework, thereby, for the first time, we extract complementary nonlinear information from the
galaxy density field before and after reconstruction in real survey data. Specifically, including $P_{\rm post}$ and $P_{\rm cross}$ in addition to $P_{\rm pre}$ (hereafter $P_{\rm all}$) yields an improvement of approximately $18$-$27\%$ in the $\sigma_8$ constraint in both $\Lambda$CDM and $w$CDM, depending on the
redshift bin, relative to the $P_{\rm pre}$-only analysis with the
cosmic microwave background distance priors (hereafter CMB). In $w$CDM, the joint CMB+$P_{\rm all}$ analysis can tighten the constraints on $w$ by approximately $5$-$15\%$ across the two LRG
redshift bins, compared to the CMB+$P_{\rm pre}$ combination. Further incorporating the Type Ia
supernova dataset and comparing the cosmological constraints in $w$CDM from each individual power-spectrum component with those from the full combination, we find that $P_{\rm all}$ consistently provides the tightest constraints. From the joint CMB+$P_{\rm all}$+DES-Dovekie
dataset, we obtain $\Omega_m = 0.314 \pm 0.0048$ and $w = -0.988 \pm 0.023$ for the LRG1 sample, and $\Omega_m = 0.318 \pm 0.0046$ and $w = -0.988 \pm 0.025$ for LRG2. These results demonstrate that combining pre- and post-reconstruction power spectra with their cross-correlation enables DESI to harvest additional nonlinear information, leading to tighter constraints on cosmological parameters.
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All authors Yuting Wang, Gong-Bo Zhao, Kazuya Koyama, Ruiyang Zhao, Takahiro Nishimichi, Zhongxu Zhai, Héctor Gil-Marín, Hanyu Zhang, Jessica Nicole Aguilar, Steven Ahlen, Florian Beutler, Davide Bianchi, David Brooks, Francisco Javier Castander, Todd Claybaugh, Andrei Cuceu, Axel de la Macorra, Arnaud de Mattia, Biprateep Dey, Peter Doel, Daniel J. Eisenstein, Simone Ferraro, Jaime E. Forero-Romero, Enrique Gaztañaga, Satya Gontcho A Gontcho, Gan Gu, Gaston Gutierrez, ChangHoon Hahn, Klaus Honscheid, Cullan Howlett, Dick Joyce, Stephanie Juneau, Robert Kehoe, David Kirkby, Theodore Kisner, Jean-Paul Kneib, Anthony Kremin, Claire Lamman, Martin Landriau, Laurent Le Guillou, Marc Manera, Aaron Meisner, Roman Miquel, Seshadri Nadathur, Jeffrey A. Newman, Enrique Paillas, Will J. Percival, Francisco Prada, Ignasi Pérez-Ràfols, Alberto J. Rosado-Marín, Ashley J. Ross, Graziano Rossi, Lado Samushia, Eusebio Sanchez, Edward F. Schlafly, David Schlegel, Michael Schubnell, Hee-Jong Seo, Joseph Harry Silber, David Sprayberry, Gregory Tarlé, Xiaoma Wang, Benjamin Alan Weaver, Shuo Yuan
Cosmology and Nongalactic Astrophysics
Interpretation of 21 cm Auto Power Spectrum Measurement at $z\sim 1$ by the Canadian Hydrogen Intensity Mapping Experiment
CHIME Collaboration, Mandana Amiri, Kevin Bandura et al. (+21 more)
Observations with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) have been used to measure the 21 cm intensity mapping auto power spectrum, at $z\sim 1$, over a frequency range from 608.2 MHz to 707.8 MHz at wavenumbers $0.4~h~{\rm Mpc}^{-1} \lesssim k \lesssim 1.5~h~{\rm Mpc}^{-1}$. In this paper, we present the results of two different approaches to interpreting this measurement. In the first approach, we use a parametric power spectrum model to constrain an amplitude parameter, defined as $\mathcal{A}^2_{\rm HI} \equiv 10^6 \Omega_{\rm HI}^2(b^2_{\rm HI}+\langle f \mu^2\rangle)^2$, where $\Omega_{\rm HI}$ is the cosmological density parameter for atomic hydrogen ($\rm HI$), $b_{\rm HI}$ is the linear bias for $\rm HI$, and $\langle f \mu^2\rangle$ incorporates the dominant large-scale impact of
redshift-space distortions on the angle-averaged power spectrum. Imposing an additional prior on either $\Omega_{\rm HI}$ or $b_{\rm HI}$, based on values in the literature, allows us to break the pairwise degeneracy between those two parameters. In the second approach, we compare CHIME's measurement with predictions for the power spectrum of $\rm HI$ from the IllustrisTNG simulations, finding that the measurement disagrees with the TNG100 run at $3.1\sigma$ and the TNG300 run at $4.0\sigma$. This disagreement is most likely attributable to the strength of nonlinear
redshift-space clustering of $\rm HI$ in the simulations, rather than the total abundance of $\rm HI$, and invites further investigation of the physical processes in the simulations that determine the behavior of $\rm HI$ at nonlinear scales. These results exemplify the ability of 21 cm intensity mapping to provide astrophysical information using measurements at nonlinear scales.
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All authors CHIME Collaboration, Mandana Amiri, Kevin Bandura, Arnab Chakraborty, Zhuo Yu Brian Chu, Matt Dobbs, Simon Foreman, Liam Gray, Mark Halpern, Gary Hinshaw, Albin Joseph, Nolan Kruger, Joshua MacEachern, Kiyoshi W. Masui, Juan Mena-Parra, Laura Newburgh, Tristan Pinsonneault-Marotte, Alex Reda, Shabbir Shaikh, Seth R. Siegel, Yukari Uchibori, Keith Vanderlinde, Haochen Wang, Dallas Wulf
High Energy Astrophysical Phenomena
Double-Adiabatic Equations of State for Relativistic Plasmas
Agnieszka Wierzchucka, Pablo J. Bilbao, Alexander G. R. Thomas et al. (+2 more)
The adiabatic equation of state $P \propto n^{\Gamma}$ describes the pressure
evolution of highly collisional, isotropic
plasmas in terms of their density, providing a possible closure of the fluid moment hierarchy in the absence of heat fluxes and dissipation. An analogous closure exists for collisionless, magnetised
plasmas, whose pressure tensor is anisotropic with respect to the
magnetic field, and the closure is therefore double adiabatic, prescribing the
evolution of the parallel and perpendicular pressures in terms of the
magnetic-field strength and density. Here, we present a general first-principle formalism to derive adiabatic laws using the
symmetries of the system. With this theory we recover the adiabatic equation of state $P \propto n^{\Gamma}$ for isotropic
plasmas and the double-adiabatic equations of state for collisionless, magnetised
plasmas. We extend the latter to the relativistic regime, finding that their exact functional form depends on the pressure anisotropy and is not a simple power law. Our double-adiabatic equations of state describe simple geometries, like
magnetic mirrors or compressed homogeneous
plasmas, as well as complex high-energy astrophysical processes, such as the
evolution of plasmoid structures formed during
magnetic reconnection.
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All authors Agnieszka Wierzchucka, Pablo J. Bilbao, Alexander G. R. Thomas, Dmitri A. Uzdensky, Alexander A. Schekochihin
Astrophysics of Galaxies
Painting a full radio sky – Empirical mock catalogues with multiple source populations for future radio surveys
Tommaso Ronconi, Anna Bonaldi, Marta Spinelli et al. (+7 more)
Upcoming
radio surveys will probe the sky with unprecedented depth and sky coverage, enabling a broad range of cosmological and astrophysical applications, as well as powerful synergies with experiments at other wavelengths. The preparation and scientific exploitation of these surveys require realistic mock catalogues that capture the complexity of the
radio sky and the interplay of its emitting components. We present a modular and extensible
algorithm for generating empirical simulations over the full
radio sky, i.e. a solid angle of $4\pi$ steradians ($f_{\rm sky}=1$), down to
redshift $z=5$, comprising both
radio continuum and line emission. The framework combines a simulated dark-matter light-cone with empirically sampled
galaxy populations and a probabilistic
galaxy-
halo assignment scheme, producing self-consistent mock catalogues including multiple
radio populations on the same light-cone. We release two public catalogues: a shallow catalogue, fully constrained by existing observational data and limited to flux thresholds of $S_\text{1.4 GHz}^\text{lim} \sim 8\times10^{-5}\ \text{Jy}$ at $1.4\ \text{GHz}$ and $S_\text{21}^\text{lim} \sim 2\ \text{Jy}\cdot\text{Hz}$ for the HI 21 cm line; and a deep catalogue extending the calibrated empirical model to better sensitivities, broadly matching future SKAO surveys, with flux limits of $S_\text{1.4 GHz}^\text{lim} \sim 4\times10^{-5}\ \text{Jy}$ and $S_\text{21}^\text{lim} \sim 0.3\ \text{Jy}\cdot\text{Hz}$. The catalogues include
radio continuum active
galactic nuclei and
star-forming
galaxies, together with HI-emitting
galaxies, for a total of more than 260 million sources in the shallow catalogue and more than 1 billion in the deep catalogue. We validate the simulations by analysing their statistical properties: the mocks reproduce the targeted clustering and population statistics while retaining minimal physical assumptions.
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All authors Tommaso Ronconi, Anna Bonaldi, Marta Spinelli, Ivano Baronchelli, Meriem Behiri, Matteo Calabrese, Carmelita Carbone, Marika Giulietti, Andrea Lapi, Marcella Massardi
Astrophysics of Galaxies
Ice chemistry that can be unveiled with the JWST: SynthIceSpec, a synthetic spectrum generator to test spectral limits. Solid CO_2 as a dust thermometer and solid CH_3CN detectability in cold cores
A. Taillard, P. Gratier, J. A. Noble et al. (+7 more)
As the (JWST) pursues its observing journey, several thousands of icy-grain spectra are expected to be measured and analysed. The inventory of ices in particular, via the observations of background sources, is accessible for hundreds of lines of sight (LOSs) per molecular-cloud region, opening the possibility to add strong constraints on the solid phase chemistry in a vast domain of cloud densities. SynthIceSpec is a synthetic infrared (IR) spectrum generator that has been designed as a tool to support observing proposals and to test the outcome of chemical models. It is based on laboratory measurements of pure and mixed ices, where each vibrational component is fitted by a sum of Gaussian profiles. Given an initial ice chemical composition (either set by the user or the outputs of a chemical model), a full JWST spectrum is generated, to which the contribution of silicates; continuum,
stellar photospheric absorption bands; and extinction law can be added. For the continuum,
stellar photospheric models for a wide range of spectral types can be selected by the program, or, Spectral Energy Distribution (SEDs). We present a few use cases of SynthIceSpec: we probed the impact of
dust temperature on CO_2 ice formation using IR data and gas-grain modelling. Next, we used SynthIceSpec to explore the detectability of the main feature of CH_3CN at 4.45 um in a cold core environment with the JWST, which was previously tentatively detected in YSOs. The detection thresholds we derive are reasonably low and observable, but identification is directly impacted by the photosphere absorptions that can greatly hinder identification. For some photostellar types, it could remain feasible. Coupled with the Estimated Time Calculator of the Space
Telescope Science Institute, SynthIceSpec can be used to find the optimum observational setup for new observations.
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All authors A. Taillard, P. Gratier, J. A. Noble, E. Dartois, A. C. A. Boogert, J. Keane, A. Clement, A. Maiolo, A. Fuente, V. Wakelam
Astrophysics of Galaxies
Inferring the mass of the circumgalactic medium using X-ray resonant scattering
Nhut Truong, Maxim Markevitch, Dylan Nelson et al. (+1 more)
The circumgalactic medium (CGM) regulates
galaxy growth and retains the imprint of feedback from
supernovae and supermassive black holes. However, the bulk of the hot CGM produces little X-ray emission and is challenging to study with X-ray
telescopes. We propose a novel method for evaluating the CGM mass using resonant scattering of the helium-like oxygen (\ovii) resonant line at $E=574$ eV. In a spherically symmetric and static CGM
halo with a sharp central X-ray peak, the number of \ovii\ ions within an outer radial shell can be calculated from the ratio of the two directly observable quantities: the \ovii\ flux from the bright inner region and the scattered \ovii\ flux from the shell (where the scattered flux can be much higher than the intrinsic emission). To evaluate the accuracy of this
geometric estimate for realistic
galaxies – with satellites, asymmetries, and gas velocities – we use a sample of
galaxies from the TNG50 cosmological simulation. We find that, when the most irregular systems are excluded based on their X-ray observables, we accurately predict the \ovii\ mass in the outer
halo (e.g., in an $r=R_{\rm 500c}-R_{\rm 200c}$ shell) from the ratio of the fluxes in the corresponding annulus and the central peak region ($r<0.2R_{\rm 500c}$), with only a 10% bias and an rms scatter of $\sim 0.2$ dex. As \ovii\ mass strongly correlates with the total oxygen and gas mass, this direct \ovii-counting method enables indirect estimates of those quantities by future X-ray microcalorimeter missions, such as NewAthena\/ and HUBS.
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All authors Nhut Truong, Maxim Markevitch, Dylan Nelson, Chris Byrohl
Cosmology and Nongalactic Astrophysics
Universality Classes of Interacting Dark Energy from Spontaneous Symmetry Breaking
Pradosh Keshav MV, NS Kavya and Kenath Arun
Phenomenological models of interacting dark energy (IDE) often treat the late-time activation history of the dark sector coupling as an independent function. We show that in conformally coupled scalar–tensor theories, this freedom is constrained by the local restoring structure of the
symmetry-breaking potential. Within the adiabatic tracking regime, the coupling
evolution satisfies $n=3/p$, where $p$ is the restoring order near the broken minimum thereby organizing distinct
symmetry-breaking potentials such as quartic, Coleman–Weinberg, and
axion-like forms into a common asymptotic dynamical class ($p=1$, $n=3$). We test this framework using Planck~2018 CMB
lensing, RSD, and
supernova data. Current observations provide only limited discrimination between the predicted activation classes and yield no statistically significant evidence for a nonzero interaction with $|\beta_0|\lesssim0.26$ at $95%$ credibility. The rigid asymptotic implementation ($n=3$) is strongly disfavored by the combined
geometric and growth constraints indicating that the observable coupling history cannot be identified directly with its asymptotic attractor form. In the heavy-scalar adiabatic regime, the modifications to the growth rate $f(z)$ and growth factor $D(z)$ are of opposite sign throughout $0\le z\le2$, suppressing the net deviation in $f\sigma_8(z)$ to $\Delta f\sigma_8/f\sigma_8\lesssim0.3%$ across the posterior. Standard growth-rate measurements therefore have limited sensitivity to this class of models, shifting the observational focus toward probes that constrain $f(z)$ and $D(z)$ independently. Taken together, these results establish a dynamical classification of late-time IDE activation histories and clarify how finite-
redshift observables are related to the asymptotic attractor structure and the local restoring properties of the underlying scalar potential.
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High Energy Astrophysical Phenomena · Cross-listed from physics.plasm-ph
On the double-adiabatic equations in the relativistic regime
Francisco Ley, Aaron Tran and Ellen G. Zweibel
We revisit the double adiabatic
evolution equations and extend them to the relativistic and ultrarelativistic regimes. We analytically solve the relativistic, time-dependent drift kinetic equation for a homogeneous, magnetized, collisionless
plasma and obtain a solution explicitly dependent on the
magnetic field and density variations. In the case of an initial relativistic Maxwellian distribution, a natural extension to an anisotropic Maxwell-Jüttner is obtained. We calculate the moments of this time-dependent solution and obtain analytical expressions for the
evolution of the perpendicular and parallel pressures in the ultrarelativistic case. We numerically solve the moment equations in the relativistic case and obtain general expressions for the double-adiabatic equations in this regime. We confirm our results using fully kinetic particle-in-
cell simulations of shearing and compressing boxes. Our findings can be readily applied to relativistic species including
cosmic-rays and electron-positron pairs, present in astrophysical
plasmas like
pulsar wind nebulae, astrophysical jets, black hole
accretion flows, and Van Allen radiation belts.
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Solar and Stellar Astrophysics
POP-CORN: Validation of a new coronal hole detection tool based on neural networks
K.H.P. Henadhira Arachchige, B. Perri and A.S. Brun
The properties and spatial distribution of large-scale structures of the
solar corona determine the observed
solar wind structure at 1 au. Coronal holes are a major source of fast
solar wind, an important geo-effective component, and appear as large dark patches in extreme ultraviolet images.
Solar observatories provide images of the
solar corona at different wavelengths, enabling identification of coronal hole morphology and other large-scale structures along a given line of sight. The problem is that although models exist, few work in real time, separate coronal holes from other dark features, or are fully automatic and suitable for comparison with models. The main goal of this work is to develop an automatic threshold-based coronal hole detection tool across
solar cycles 23, 24, and 25 using artificial intelligence. The only user input is the date, enabling
retrieval of the threshold value used to detect coronal hole contours in line-of-sight extreme ultraviolet images from SDO/AIA and SoHO/EIT. We retrieve data affecting the threshold due to contrast changes from the Heliophysics Events Knowledge database for large-scale features such as active regions,
solar flares, coronal mass ejections, and filaments, and engineer them to train the neural network model (POP-CORN). The model input comprises categorical features of large-scale structures in the
solar corona, including spatial distribution and properties such as
solar flare class by intensity. The neural network model is trained to achieve higher accuracy and determines the threshold needed to detect coronal holes, allowing their boundaries to be identified automatically and consistently. We conclude that properties of large-scale structures affect the determination of coronal hole regions, and incorporating these properties into training improves detection.
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Cosmology and Nongalactic Astrophysics
Particle Physics and Gravitational Waves as complementary windows on the Universe
Steven D. Bass, Laura Baudis, Gianfranco Bertone et al. (+16 more)
Particle physics and gravitational waves provide complementary probes of the deep structure of the Universe. Gravitational waves from the mergers of
neutron stars and black holes are sensitive to the structure of dense
quark matter and to different dark matter scenarios. Measurements of
stochastic gravitational waves backgrounds can teach us about possible first order phase transitions in the early Universe, including providing sensitivity to the TeV scale which is of key interest to future particle
collider experiments. Gravitational waves measurements will also give new probes of the
evolution and expansion of the Universe, complementary to measurements with electromagnetic radiation. This Perspectives article explores the physics synergies between the science opportunities provided by next generation gravitational waves measurements and particle physics experiments. Gravitational waves can also probe deep into the early Universe reaching physics much above possible
collider energies if the signals can be detected.
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All authors Steven D. Bass, Laura Baudis, Gianfranco Bertone, Oliver Buchmueller, Babette Döbrich, Reinhard Genzel, Anne M. Green, Klaus Helbing, Michèle Heurs, Karl Jakobs, Markus Klute, Samaya Nissanke, Hiranya Peiris, Albino Perego, Stefan Pokorski, Matthias Schott, Stefano Vitale, Georg Weiglein, Jochen Weller
Astrophysics of Galaxies
The Impact of Fuzzy Dark Matter Dynamics on the Accumulation and Fragmentation of Primordial Gas
Alexander Tocher, Anastasia Fialkov, Simon May et al. (+4 more)
Fuzzy Dark Matter (FDM), particularly in the $10^{-22}$ eV mass regime is frequently used to characterize wave-like interference effects. It exhibits macroscopic wave properties, which drive distinct baryonic dynamics within collapsed
haloes. Using the hydrodynamical code AREPO with the AxiREPO module and
primordial chemistry, we simulate the assembly of
haloes with masses $3 \times 10^{8} \le M_{\mathrm{h}} \le 8 \times 10^{9} \: M_\odot$ across a range of
axion masses $1 \times 10^{-22} \le m_{\mathrm{a}} \le 7 \times 10^{-22}$ eV. We investigate how small-scale dynamics of the FDM density field affect the accumulation of cold, dense gas essential for
primordial star formation. We demonstrate that gas collapse is suppressed by a two-fold mechanism: a delay driven by the geometry of the FDM solitonic core and a secondary dynamical barrier caused by
stochastic wave fluctuations. While the flattened solitonic potential profile itself inhibits central gas accumulation, these wave-driven dynamics provide a further layer of disruption and angular momentum support, which in certain regimes prevents gas from reaching the central, compact, high-density configurations characteristic of CDM. Consequently, sites of
star formation are shifted away from a single central peak toward a population of lower-mass clusters. Our work provides a physical framework for calibrating
halo mass-dependent
star formation efficiencies in FDM cosmologies, where internal processes may delay
Cosmic Dawn beyond the effects of the initial power spectrum cut-off. These results are essential for interpreting realistic observational constraints from future 21-cm signal observations and the faint-end luminosity functions observed by the JWST, as well as providing an upper bound on the baryonic effects in the context of Mixed Dark Matter scenarios.
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All authors Alexander Tocher, Anastasia Fialkov, Simon May, Ralf S. Klessen, Simon C. O. Glover, Paul C. Clark, Tibor Dome
Instrumentation and Methods for Astrophysics
Bayes-SCF: A Bayesian filter to mitigate foreground leakage in the 21-cm power spectrum
Khandakar Md Asif Elahi
Missing channels in
radio-interferometric visibility data can introduce systematic artefacts into the estimated 21-cm power spectrum. A common workaround is to first estimate the two-frequency correlation $C(\Delta\nu)$ and then
Fourier-transform it to obtain the power spectrum $P(k_\parallel)$. This procedure yields an unbiased estimate when the signal is statistically homogeneous (ergodic) along the line-of-sight, but it fails in the presence of non-ergodic foregrounds. Smooth Component Filtering (SCF) has recently been proposed as a solution to this problem, in which the dominant non-ergodic (spectrally smooth) component is removed prior to estimating $C(\Delta\nu)$. In existing implementations, the smooth component is estimated by convolving the visibilities with a Hann window along the frequency axis. We demonstrate that this Hann-based SCF performs adequately only when foregrounds are extremely spectrally smooth. It breaks down with increased flagging and when foregrounds exhibit spectral structures. We introduce a
Bayesian extension, Bayes-SCF, based on Gaussian Process regression, which overcomes these limitations. Bayes-SCF models the smooth component via a covariance function with a fixed correlation length, enabling controlled and data-driven filtering. Using simulated data, we show that Bayes-SCF robustly recovers the input model 21-cm power spectrum in the presence of spectrally unsmooth foregrounds. The filter is demonstrated to work under different flagging patterns, including $80\%$ channels being randomly flagged. Bayes-SCF is also effective in a delay-spectrum approach. The primary trade-off introduced by the
Bayesian framework is the increased computational cost; future work will focus on optimizing the
algorithm and applying it to real Murchison Widefield Array data.
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Earth and Planetary Astrophysics
The Circumbinary Disc of HD 34700A II. Analysis of a strong dust asymmetry
Daniele Fasano, Myriam Benisty, Jochen Stadler et al. (+8 more)
ALMA observations have shown that substructures are ubiquitous in protoplanetary discs. A sub-group, the transition discs, shows large cavities and rings in
dust continuum. Among these, some present very high contrast asymmetries possibly due to the presence of
vortices. HD 34700A is a binary system featuring a cavity, a ring, and multiple spiral arms detected in scattered light, a prominent crescent in the ALMA continuum and a complex gas morphology possibly connected with ongoing infall. We present new ALMA band 6 (1.3 mm) continuum images of the circumbinary disc around HD 34700A and compare them with two other systems showcasing high ($\gtrsim30$, measured as the peak-to-azimuthal-average ratio) contrast continuum asymmetries, IRS 48 and HD 142527. We aim to characterise the crescent morphology and discuss their possible origin. We perform visibility modelling of the new high resolution (0.”11x0.”09) ALMA band 6 continuum data of HD 34700A, together with improved visibility modelling of the other two targets. Our visibility model is in remarkable agreement with the HD 34700A data, featuring only localised residuals in the region of the disc corresponding to the tail of the asymmetry. We reproduce the double-peaked emission in HD 142527, and recover the crescent shape in IRS 48. We then run a hydrodynamic model of a
vortex with different
dust fluids, reproducing the general asymmetric crescent morphology observed in the HD 34700A and IRS 48 systems. With a combination of visibility,
dust evolution and hydrodynamical models, we have constrained the morphology of the
dust continuum emission of HD 34700A for the first time, and improved existing models for IRS 48 and HD 142527. The high azimuthal contrast of the asymmetries rules out the orbit clustering of eccentric cavities scenario, while the
dust evolution models we consider suggest that the
vortex scenario is a plausible option.
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All authors Daniele Fasano, Myriam Benisty, Jochen Stadler, Francesco Zagaria, Alexandros Ziampras, Andrew J. Winter, Jaehan Bae, Stefano Facchini, Nicolás T. Kurtovic, Enrico Ragusa, Richard Teague
High Energy Astrophysical Phenomena · Cross-listed from hep-ph
QED cross sections in strong magnetic fields
Olavi Kiuru, Joonas Nättilä, Risto Paatelainen et al. (+1 more)
The magnetospheres of magnetars, a class of highly magnetized
neutron stars, host
magnetic fields exceeding the Schwinger limit, where
Quantum Electrodynamics (QED) becomes nonlinear. In such environments, QED scattering processes are strongly modified, which may affect
plasma dynamics. In this work, we apply a formalism originally developed for the study of
magnetic-field effects in hot
quark-
gluon plasma to strong-field QED. The method resums interactions between virtual electrons and the external
magnetic field, consistently incorporating the finite decay widths of excited Landau levels derived from the
fermion self-energy. Using this framework, we perform the first systematic analysis of tree-level QED scattering processes in strong
magnetic fields, concentrating on the processes of highest relevance for the
plasma dynamics of magnetars. All resulting cross sections are provided in an open-source Python package.
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All authors Olavi Kiuru, Joonas Nättilä, Risto Paatelainen, Aleksi Vuorinen
Instrumentation and Methods for Astrophysics
Advancing weak lensing mass mapping with a mask-aware HEALPix transformer
Yihe Wang and Yu Yu
We present HEALFormer, a
transformer-based neural network architecture for weak gravitational
lensing mass mapping that reconstructs convergence maps from incomplete and noisy shear observations on the celestial sphere. The model operates directly on the Hierarchical Equal Area isoLatitude Pixelization and employs learnable mask
tokens to handle arbitrary survey geometries without requiring preprocessing. Through a progressive training strategy, HEALFormer efficiently processes high-resolution maps up to Nside = 1024 and demonstrates excellent performance across diverse survey footprints including KiDS, DES, DECaLS, and Planck. The model generalizes robustly to cosmological parameters beyond its training set, producing nearly unbiased reconstructions with superior noise suppression compared to traditional Kaiser-Squires and Wiener filter methods. Remarkably, HEALFormer exceeds the theoretical phase recovery limits of linear reconstruction methods at small scales, achieving a fundamental breakthrough in weak
lensing analysis. The combination of computational efficiency, reconstruction accuracy, and adaptability to varying survey configurations makes HEALFormer well-suited for current and next-generation cosmological surveys. Code is available at GitHub.
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Solar and Stellar Astrophysics · Cross-listed from nucl-th
Vittorio Barlucchi, Alex Gnech, Scilla Degl'Innocenti et al. (+1 more)
The astrophysical $S$-factor for the
proton-
proton fusion is calculated in the low-energy regime for a variety of
nuclear interactions and consistent
nuclear currents, derived within
chiral effective field theory. We estimate, for the first time, the theoretical uncertainty on the $S$-factor due to the truncation of the
chiral expansion of the currents using a
Bayesian analysis. In order to reach an accuracy at the percent level in the calculation, the electromagnetic potential includes contributions beyond the leading Coulomb interaction, such as two-
photon exchange and
vacuum polarization. The initial
proton-
proton state is expanded in partial waves and only the ${}^1S_0$ contribution is included, as it is known that the other partial-waves effects are negligible. The low-energy constant entering the contact term in the weak axial current operator is calibrated to reproduce the Gamow-Teller
matrix element in Tritium $\beta$-decay. The value $S(0)$ is found to be $S(0)=(4.068 \pm 0.025)\times 10^{-25} \: \text{MeV}\: \text{b}$.
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All authors Vittorio Barlucchi, Alex Gnech, Scilla Degl'Innocenti, Laura Elisa Marcucci
Solar and Stellar Astrophysics
Implementation of a Near-Realtime Recording and Reporting System of Solar Radio Bursts
Peijin Zhang, Anastasia Kuske, Bin Chen et al. (+48 more)
Strong
solar activity is often accompanied by a variety of
radio bursts. These bursts are valuable diagnostics of coronal and heliospheric processes and also have potential applications in space weather monitoring and
forecasting. However, space weather applications require low-latency, high-sensitivity
radio burst recording and reporting capabilities, which have remained limited. In this work, we present the development of a near-realtime
radio burst recording and reporting system using the Owens Valley
Radio Observatory Long Wavelength Array. The system directly clips data from a realtime buffer and streams them as a live
radio dynamic spectrogram. These spectrograms are then processed by a deep-learning-based burst identification module for type III
radio bursts. The identifier is based on a YOLO (You Only Look Once) architecture and is trained on synthetic type III
radio bursts generated using a physics-based model to achieve accurate and robust detection. This system enables continuous realtime
radio spectrum streaming and automatic reporting of type III
radio bursts within approximately 10 seconds of their occurrence.
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All authors Peijin Zhang, Anastasia Kuske, Bin Chen, Mengjia Xu, Gelu Nita, Marin M. Anderson, Judd D. Bowman, Ruby Byrne, Morgan Catha, Xingyao Chen, Sherry Chhabra, Larry D'Addario, Ivey Davis, Jayce Dowell, Katherine Elder, Dale Gary, Gregg Hallinan, Charlie Harnach, Greg Hellbourg, Jack Hickish, Rick Hobbs, David Hodge, Mark Hodges, Yuping Huang, Andrea Isella, Daniel C. Jacobs, Ghislain Kemby, John T. Klinefelter, Matthew Kolopanis, Nikita Kosogorov, James Lamb, Casey Law, Nivedita Mahesh, Surajit Mondal, Brian O'Donnell, Kathryn A. Plant, Corey Posner, Travis Powell, Vinand Prayag, Andres Rizo, Andrew Romero-Wolf, Jun Shi, Greg Taylor, Jordan Trim, Mike Virgin, Akshatha Vydula, Sandy Weinreb, Scott White, David Woody, Sijie Yu, Thomas Zentmeyer
Solar and Stellar Astrophysics
The Effect of Expansion and Instabilities in the Thermodynamic Regulation of the Young Solar Wind Plasma
Matilde Coello-Guzmán, Víctor A. Pinto, Roberto E. Navarro et al. (+1 more)
Using Parker
Solar Probe measurements of the
solar wind, we demonstrate that $\beta_{\parallel}$ is the main driver that determines which instabilities limit
proton temperature anisotropy. At radial distances from 10 to 30
solar radii, $\beta_{\parallel}<1$ drives electromagnetic ion-cyclotron and parallel firehose instabilities, in contrast to the situation at 1 astronomical unit, where, due to most $\beta_{\parallel}>1$, mirror and oblique firehose modes are dominant instead. Furthermore, we show that the temperature anisotropy radially evolves following the semi-empirical anti-correlation $T_\perp/T_\parallel\sim\beta_\parallel^{-0.55}$, consistent with observations at larger distances from the Sun.
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All authors Matilde Coello-Guzmán, Víctor A. Pinto, Roberto E. Navarro, Pablo S. Moya
Solar and Stellar Astrophysics
Probing the Solar Corona and the Solar Wind Using Angular Broadening Observations with the SKA
Peijin Zhang, John Morgan, Divya Oberoi et al. (+9 more)
Angular broadening observations of compact
radio sources provide a powerful method for probing the
solar corona and
solar wind. Such observations enable studies of the phase structure function,
turbulence amplitude, intermediate-scale density fluctuations,
solar-wind heating rates, and dissipation scales. When a compact
radio source is observed through coronal or
solar-wind
plasma, several observable effects can arise: (1) the apparent source size increases because of scattering by turbulent
plasma, producing angular broadening; (2) the source flux density decreases because of scattering and absorption; (3) the observed angular broadening can be anisotropic, reflecting anisotropic
turbulence in the corona and
solar wind; and (4) the position angle of the anisotropy, measured from north through east, can help infer the orientation of the coronal
magnetic field. These effects provide insights into the physical processes governing the
solar wind and its interaction with electromagnetic waves, and they offer constraints on coronal
turbulence and
magnetic-field structure. At present, angular broadening studies remain limited and have mostly focused on very bright
radio sources such as Tau A. The unprecedented sensitivity and angular resolution of the Square Kilometre Array are expected to greatly expand the number of suitable background sources, opening a new window on the
solar corona,
solar wind, and heliosphere.
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All authors Peijin Zhang, John Morgan, Divya Oberoi, Du Toit Strauss, Yingjie Luo, Eduard Kontar, Zesen Huang, Keshav Aggarwal, Anshu Kumari, Abhirup Datta, Diana E. Morosan, Gert J. J. Botha
Solar and Stellar Astrophysics
Eclipsing binary classification with machine learning techniques
Bedri Keskin and Özgür Baştürk
We focus on the automated classification of eclipsing binary
stars using deep learning methods to handle the vast data generated by large-scale photometric sky surveys. These surveys produce extensive
datasets that are impractical for manual analysis. By using machine learning to classify eclipsing binary
stars based on light curve morphology, this study aims to contribute to the efforts to efficiently process and accurately interpret massive data from projects Kepler, TESS and
Gaia missions.
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Astrophysics of Galaxies
Tracing neutral hydrogen in UGCA 320: A MHONGOOSE perspective on an edge-on dwarf galaxy in a group environment
Nikki Zabel, D.J. Pisano, Sushma Kurapati et al. (+8 more)
We present a detailed analysis of the neutral atomic gas (HI) in the
dwarf galaxy UGCA 320, observed with the MeerKAT
telescope as part of the MHONGOOSE (MeerKAT HI Observations of Nearby
Galactic Objects: Observing Southern Emitters) programme. In a small group consisting of three
dwarf galaxies, all of which contain HI, it is the most massive. Detailed kinematic modelling shows that UGCA 320 contains a substantial amount of (kinematically) anomalous gas (>=20%), at least ~30% of which is likely the result of a
tidal interaction with its neighbour UGCA 319. It also reveals that UGCA 320 likely harbours a
star-formation driven
outflow, and that ~10% of its HI is extra-planar and has a filamentary structure. Although UGCA 320 aligns with established scaling relations from the literature, its neutral hydrogen content is notably complex - shaped by its immediate environment. This underscores the importance of deep, resolved observations and detailed kinematic analyses to capture the nuances of
galaxy evolution.
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All authors Nikki Zabel, D.J. Pisano, Sushma Kurapati, Omri Scannell, Notahiana Ranaivoharimina, Julia Healy, Erwin de Blok, Peter Kamphuis, Adebusola B. Alabi, S. Ilani Loubser, Moses K. Mogotsi
Instrumentation and Methods for Astrophysics
Development of ProtoPol: a medium resolution echelle spectro-polarimeter for PRL telescopes, Mt Abu, India – Part II : the data-reduction pipeline, on-sky characterization $\&$ performance verification and first science results
Arijit Maiti, Mudit K. Srivastava, Vipin Kumar et al. (+5 more)
We present the development of ProtoPol - a medium resolution echelle spectro-polarimeter for the PRL 1.2m and 2.5m
telescopes at Mt Abu observatory, India. In this second and final part of the paper series, we report on the development of a dedicated data reduction pipeline of ProtoPol along with several characterization, performance evaluation, and scientific observations to quantify the performance of the instrument. ProtoPol provides a spectral resolution in the range of $\sim$0.4 - 0.75 angstrom across various orders in the visible wavelength range of 4000-9600 angstrom. On PRL 2.5m
telescope, an SNR of 10 is achieved for $m_V\sim13.2$ source in 1 hour of integration time, and its throughput is estimated to be $\sim$6% including all the contributing factors such as atmospheric transmission,
telescope reflectivity, instrument's optics, CCD efficiency etc. ProtoPol achieved a linear polarization accuracy $\delta P \approx 0.1-0.2\%$ in 2 hours of integration time for a source with $m_V\approx8$. The instrumental polarization is determined to be around $0.1\%$. We also present the first science results with ProtoPol to demonstrate the capabilities of the instrument. A sample of Herbig Ae/Be
stars, classical Herbig
stars, Symbiotic
stars, and AGB/post-AGB
stars were observed over the period of one and half years for their spectro-polarimetry measurements covering various physical mechanisms such as intrinsic line polarization in Herbig and classical Be
stars, Raman scattered features in Symbiotic
stars, as well as continuum polarization in AGB/post-AGB
stars to verify the polarization performance of the instrument.
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All authors Arijit Maiti, Mudit K. Srivastava, Vipin Kumar, Bhaveshkumar Mistry, Ankita Patel, Vaibhav Dixit, Ruchi Pandey, Jay Chitroda
Cosmology and Nongalactic Astrophysics
Cluster gravitational redshifts: uncertainties and survey requirements
Eleni Tsaprazi, Giorgio F. Lesci, Federico Marulli et al. (+2 more)
We investigate the impact of observational and theoretical uncertainties in cluster gravitational
redshifts as a probe of modified
gravity using an end-to-end
forecasting pipeline. We use a generative model to build a
halo catalogue with $M_{500}\ge 3\times 10^{13}\,M_\odot$, populate
haloes with member
galaxies via a five-parameter
halo occupation distribution (HOD), assign projected positions from radial density profiles, apply survey-like selections, and infer a linear rescaling of the gravitational potential, $\alpha_\mathrm{MG}$, to parameterise modifications to general relativity (GR). We vary
redshift uncertainties, radial and mass-
redshift completeness, member abundance, minimum mass and maximum
redshift, as well as mis-specify the clusters density and velocity profiles, centres, and mass function. We find that the intracluster velocity dispersion sets an effective floor: improving
redshift precision beyond $\sigma_z\sim 10^{-4}(1+z)$ brings no improvement in the precision of $\alpha_\mathrm{MG}$. Realistic
redshift and mass cuts primarily remove low-mass
haloes and have minimal impact on the $\alpha_\mathrm{MG}$ precision. In this setting, we find that shallow, narrower spectroscopic surveys are preferable to deep, wide photometric ones for precise modified
gravity constraints. We further find that mis-centring can mimic significant departures from GR. Baryonic deviations from a Navarro-Frenk-White profile and velocity anisotropies do not introduce appreciable biases. In the high-S/N regime of upcoming surveys, accurate determination of cluster centres will be essential to avoid interpreting systematic effects as new physics. The Spectroscopic Stage-5 Experiment and the Widefield Spectroscopic
Telescope provide a clear route toward establishing gravitational
redshifts as a competitive probe of modified
gravity.
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All authors Eleni Tsaprazi, Giorgio F. Lesci, Federico Marulli, Alan F. Heavens, Enrico Maraboli
High Energy Astrophysical Phenomena
Jet Power Estimates of FSRQs PKS 1441+25 and Ton 599 from Broadband SED Modeling
Hritwik Bora, Ranjeev Misra, Rukaiya Khatoon et al. (+1 more)
Flat-Spectrum
Radio Quasars (FSRQs) are among the most energetic and powerful active
galactic nuclei, often exhibiting jet powers comparable to or exceeding the Eddington luminosity. In this work, we performed broadband spectral energy distribution (SED) modeling of two FSRQs PKS 1441+25 and Ton 599, using Swift-XRT/UVOT, NuSTAR,
Fermi-LAT and VERITAS observations during 2015 and 2021, respectively. We considered four particle distribution models: a broken power law, a log-parabola, and two energy-dependent models in which either the
diffusion or acceleration timescale depends on energy. Our results show that the jet power estimates derived from models with intrinsic
curvature, such as the log-parabola and energy-dependent models, are of the same order as those obtained with a broken power-law distribution. This contrasts with the case of High Synchrotron Peaked Blazars (HBLs), where the power estimates can differ by nearly two orders of magnitude between models. We attribute this difference to the lower electron break energies typically observed in FSRQs. Consequently, our findings suggest that, unlike in HBLs, the estimated jet powers in FSRQs are relatively insensitive to the assumed particle energy distribution, reflecting the dominance of external Compton processes and weaker dependence on spectral
curvature.
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All authors Hritwik Bora, Ranjeev Misra, Rukaiya Khatoon, Rupjyoti Gogoi
Instrumentation and Methods for Astrophysics
Calibration of key parameters during the in-orbit phase for the Taiji-2 gravitational reference sensor
Haoyue Zhang, Chang Liu, Xiaotong Wei et al. (+4 more)
The Taiji mission, a pioneering Chinese space-borne gravitational wave observatory, requires ultra-precise calibration of its gravitational reference sensors (GRSs) to achieve its targeted sensitivity of $3\times10^{-15} \mathrm{\ m\ s^{-2}\ Hz^{-1/2}}$. Maintaining this precision is challenged by time-varying scale factors drifts and dynamic center-of-mass (c.m.) offsets between the test masses (TMs) and spacecraft, driven by factors such as propellant consumption, thermal effects and aging electronics. This paper develops an advanced in-orbit calibration framework that simultaneously estimates the GRS scale factors and c.m. offsets between TMs and spacecraft through a combination of spacecraft maneuvers and Kalman filter. By applying periodic torque signals to induce controlled spacecraft angular accelerations, we leverage
star tracker and GRS readouts to disentangle coupled disturbances and achieve dual-parameter calibration with unprecedented precision, with scale factors errors below 0.2% and c.m. offsets residuals within 100 $\mathrm{\mu}$m, satisfies the Taiji-2 calibration requirements. This method is robust across different satellite configurations. The results not only ensure the feasibility of Taiji-2's scientific objectives but also establish a scalable calibration paradigm for future missions such as Taiji-3, where sub-micrometer c.m. stability and ultra-low noise gravitational reference will be essential.
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All authors Haoyue Zhang, Chang Liu, Xiaotong Wei, Peng Xu, Li-E Qiang, Ziren Luo, Ye Dong
Instrumentation and Methods for Astrophysics · Cross-listed from physics.class-ph
A note on Gurzadyan theorem
Christian Carimalo
The issue and proof of Gurzadyan
theorem are presented concisely, avoiding tedious and unnecessary calculations that would mask what is essential. The goal is to provide a good mathematical and physical understanding of the
theorem, making you want to learn more about its use in cosmology.
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Earth and Planetary Astrophysics
Interaction between vegetation and Snowball phases in the late Proterozoic Earth
Erica Bisesi, Giuseppe Murante, Antonello Provenzale et al. (+3 more)
Between 2.4 and 0.6 Gy ago, our
planet underwent several episodes of global glaciations, including the Snowball Earth case that ended 635 My ago. Causes of this last Snowball event presumably included a decreased greenhouse gas concentration and high continental albedo, both associated with the passage of the super-continent Rodinia at equatorial latitudes. When large continental masses are in equatorial regions, silicate weathering is enhanced, leading to decreased atmospheric CO2 concentration, while the bare continental masses, which at the time hosted no vegetation, enhanced reflection of
solar radiation. Since then, no other Snowball episodes were recorded. Here we numerically explore the climatic dynamics of a rocky
planet for different values of
solar output, continental configuration (current and Rodinia-like), CO2 concentration and continental albedo, simulating the effects of land vegetation. We found that for the
solar input typical of 600-700 My ago (95% of the current value), the presence of bare continents with albedo 0.35 (granite) in the position estimated for Rodinia was sufficient to trigger a Snowball state for CO2 concentrations up to at least 1000 ppm. When bare continents are located in modern positions, Snowball could be triggered only for values of CO2 concentration below 400 ppm. At current
solar input values, Snowball states appear only at or below 100 ppm. Thus, we found: a lower
solar output is an essential component of the transition to Snowball; the presence of land vegetation is crucial and reduces the probability of entering a Snowball state; a low CO2 concentration was not needed for triggering a Snowball in bare Rodinia-like conditions and reduced
solar output; current
solar luminosity does not allow Snowball states, even for equatorial continents, unless continental albedo is that of granite and CO2 concentration is 100 ppm or less. [Abridged]
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All authors Erica Bisesi, Giuseppe Murante, Antonello Provenzale, Jost von Hardenberg, Michele Maris, Laura Silva
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Non parametric constraints of gravitational-electromagnetic luminosity distance ratio
Sergio Andrés Vallejo-Peña, Antonio Enea Romano and Jonathan Gair
The ratio between the gravitational waves (GW) and electromagnetic waves (EMW) luminosity distance ratio is a key observable that allows to test the nature of
gravity, using gravitational waves emitted from compact binary coalescences. We develop a new non parametric method for constraining the GW-EMW distance ratio, in order to perform model independent analysis of observational data, not based on any specific theoretical of phenomenological assumption. We apply the method to the analysis of binary black hole mergers data from the GWTC-3 catalogue, performing a joint analysis of cosmological and population parameters. The results are consistent with general relativity and with previous analyses based on parametric methods.
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Instrumentation and Methods for Astrophysics
Development of ProtoPol: a medium resolution echelle spectro-polarimeter for PRL telescopes, Mt Abu, India – Part I : the design, development and laboratory characterization
Mudit K. Srivastava, Arijit Maiti, Vipin Kumar et al. (+4 more)
ProtoPol is a medium-resolution echelle spectro-polarimeter developed for Physical Research Laboratory (PRL) 1.2m and 2.5m
telescopes, Mt. Abu, India. Though initially conceived to evaluate the development methodology of the echelle spectro-polarimeter, it was subsequently elevated to the level of a full-fledged back-end instrument for PRL
telescopes. ProtoPol is developed on the traditional concept of using a half-wave plate with Wollaston prism to achieve the separation of two mutually orthogonal polarized beams. These separated beams are modulated and directed into an echelle spectrometer which is employs an echelle grating and two plane reflection gratings as the cross-dispersers. Therefore, the cross-dispersed spectra for two orthogonal polarized beams are recorded in multiple orders on a CCD detector. ProtoPol is designed to operate in the visible and near IR spectral range, 4000 - 9600 angstrom, with a spectral resolution ($\delta$$\lambda$) around 0.4-0.75 angstrom. The uniqueness of ProtoPol lies in its design which has entirely been developed with commercially available off-the-shelf optical and opto-mechanical components. This feature makes ProtoPol a noteworthy development as it offers a cost-effective way to develop spectro-polarimeters with such resolutions for small-aperture (2-3m)
telescopes around the world, in a much shorter development period. ProtoPol has been successfully developed and commissioned on PRL 1.2m and 2.5m
telescopes since December 2023, and a variety of observations have been carried out for instrument characterization, performance verification, and scientific purposes. This is the first of the two-part research articles series, wherein we present the design and development methodology of ProtoPol, along with its laboratory characterization and performance.
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All authors Mudit K. Srivastava, Arijit Maiti, Vipin Kumar, Bhaveshkumar Mistry, Ankita Patel, Vaibhav Dixit, Kevikumar A. Lad
Astrophysics of Galaxies
Star-Galaxy Classification in Deep LSST Data with Random Forest: A Pilot study on the Data Preview 1 Release
M. Gatto, V. Ripepi, M. Bellazzini et al. (+2 more)
The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will produce unprecedentedly deep and wide photometric catalogs, enabling transformative studies of faint
stellar systems such as the research of ultra-faint
dwarf galaxies (UFDs). A critical challenge for these studies is reliable
star-
galaxy separation at faint magnitudes, where compact background
galaxies increasingly contaminate
stellar samples. This work aims to assess the performance of supervised machine-learning techniques for
star-
galaxy separation in LSST-like data, quantify the relative importance of morphological and photometric information, and identify the most effective combinations of input features for minimizing
galaxy contamination while preserving
stellar completeness in the faint regime relevant for UFD searches. We apply a Random Forest classifier to observations of the Extended Chandra Deep Field South from LSST Data Preview 1 (DP1), the deepest field observed within the DP1. We construct a curated sample of bona fide
stars and
galaxies using spectroscopic data,
Gaia DR3, and multi-band photometric catalogs. We train and validate the classifier using several configurations of LSST-based input features, including multi-band colors, the LSST morphological parameter refExtendedness, and photometric uncertainties. We find that LSST multi-band photometry alone delivers a good
star-
galaxy separation, significantly outperforming morphology-based classification at faint magnitudes. Colors involving the u-band are essential to provide a robust
star galaxy separation. Furthermore, explicitly including photometric uncertainties as input features yields the best overall performance. Across all configurations that include all the six LSST filters,
galaxy contamination remains negligible almost the whole magnitude range probed in this work (i.e. r < 27.5 mag). [abridged]
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All authors M. Gatto, V. Ripepi, M. Bellazzini, C. Tortora, M. Dall'Ora