High Energy Astrophysical Phenomena
It Takes Two: nucleosynthesis in core-collapse supernova simulations of binary-star progenitors
Gaétan Jalin, Almudena Arcones, Evan P. O'Connor et al. (+2 more)
Binary interaction is common amongst massive
stars and can significantly alter their pre-
supernova structure and composition. This has important consequences for the nucleosynthetic yields and observable properties of the resulting
supernovae. However, binary-evolved progenitors remain largely unexplored in modern
neutrino-driven core-collapse
supernova simulations. In this work, we present one- and two-dimensional core-collapse
supernova simulations of single- and binary-
star progenitors. We investigate the impact of binary interaction on the explosion and examine the effect of in-situ networks on the dynamics and resulting nucleosynthesis relative to post-processing approaches. Our progenitors highlight the impact of binary interaction on the pre-
supernova core structure of the
star and its significance for explodability. We find that binary progenitors are predicted to be generally more explodable than single
stars with the same initial mass, indicating that the
supernova outcome cannot be well correlated with the initial mass. However, a systematic comparison of the explosion outcomes of binary- and single-
star progenitors from self-consistent simulations is still required to confirm this trend. Energy generation from nuclear reactions, as well as the abundances of key isotopes such as ${}^{56}$Ni, can be well approximated by a small $\alpha$-chain network. However, there are notable discrepancies in the production of Ti, Cr, and Fe isotopes which remain sensitive to the network size and thermodynamic history.
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All authors Gaétan Jalin, Almudena Arcones, Evan P. O'Connor, Andrea Ercolino, Norbert Langer
High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Constraining the gravitational-wave breathing mode with LVK antenna patterns and GWTC data
Hong-Bo Jin and Yanyan Zheng
Metric theories of
gravity admit a massless breathing scalar $b$ besides the tensor modes $+$ and $\times$. Many scalar–tensor models predict a much smaller breathing amplitude; gravitational
quantum field theory (GQFT) instead allows $h_b$ comparable to the tensor amplitudes. We evaluate the LIGO–Virgo–KAGRA (LVK)
antenna patterns with PyCBC, including Michelson suppression of $b$. Here $F_b$ is the breathing
antenna pattern and $\mathcal{S}_b=\sum_d F_b^{d2}$ is the network breathing power. At the H1 zenith at the GW150914 epoch, $F_b\sim 5\times 10^{-6}$; for $72$ Gravitational-wave Transient Catalog (GWTC) events with packaged strain the median inclination gain in $\mathcal{S}_b$ is $\sim 34\times$. Ranking multi-detector GWTC events (network $\mathrm{SNR}\ge 8$, $\ge 2$ sites) by $\mathrm{SNR}\sqrt{\mathcal{S}_b^{*}}$ identifies loud O4 triggers and GW170817 as
geometric targets. Parameter-estimation (PE) weighted $\mathcal{S}_b$ on twelve events shows that the true sky can suppress this ranking (GW170817) and that GW200129_065458, GW150914, and GW190814 have the highest PE-weighted $\mathcal{S}_b$ for $\xi$ in $h_b=\xi h_+$ (GR: $\xi\equiv 0$). An HLV design-noise injection grid gives $\ln B(\mathrm{GR}+b/\mathrm{GR})\approx 13$ ($4$) for $\xi=1$ ($0.5$) on an inclined sky ($\mathcal{S}_b\sim 0.18$); near zenith ($\mathcal{S}_b\sim 0.016$) the $\xi$ posterior remains unconstrained. The GWTC limits are semi-joint: masses and
spins fixed at PE medians, while $d_L$, $\theta_{JN}$, sky, and $\xi$ vary within PE-informed priors. Eleven of twelve events are analyzed (GW170817 omitted: PE sky on the breathing null). None favors $\mathrm{GR}+b$; $|\xi|_{90\%}\approx 0.15$, $0.18$, and $0.23$ for GW150914, GW200129_065458, and GW200311_115853 disfavor $|\xi|\sim\mathcal{O}(1)$, while weaker bounds (including GW190814) still allow that scale.
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Earth and Planetary Astrophysics
SOPHIE and TESS characterization of fourteen TESS Objects of Interest: nine planetary systems and five low-mass stellar companions
N. Heidari, G. Hébrard, S. Sousa et al. (+61 more)
We present fourteen TESS Objects of Interest (TOIs) from the SOPHIE-TESS follow-up program. Combining TESS photometry, SOPHIE radial velocities (RVs), ground-based photometry, and high-resolution imaging, we establish the nature of all targets. Nine systems (TOI-6457, TOI-6883A, TOI-6649, TOI-6842A, TOI-5217A, TOI-6893A, TOI-7025, TOI-7176, and TOI-5893) host
planets. TOI-6649 b, TOI-6842A b, and TOI-5217A b are transiting hot Jupiters with periods of 4.4-6.0 d, radii of 1.3-1.6 RJ, masses of 0.3-1.3 MJ, and densities of 0.1-0.6 g/cm3. TOI-5217A also hosts an outer companion, TOI-5217A c, with a period of about 1761 d, a minimum mass of about 13 MJ, and an eccentric orbit (e = 0.53 +/- 0.02). TOI-5893 b, TOI-6893A b, TOI-6457 b, TOI-7176 b, and TOI-7025 b are transiting warm Jupiters with periods of 40.4-67.0 d, radii of 0.8-1.2 RJ, and masses of 0.5-1.0 MJ. TOI-6883A b, a recently reported warm Jupiter, is further characterized with new photometry and SOPHIE and TRES RVs. The other five systems (TOI-5621AB, TOI-5321AB, TOI-3678AB, TOI-5906AB, TOI-5308AB) show large RV amplitudes indicating eclipsing binaries (companions of 0.1-0.6 Msun and 0.1-0.6 Rsun). TOI-6842A b is a super-puff (density 0.08 +/- 0.01 g/cm3), among the nine lowest-density
planets known, and with a transmission spectroscopy metric of about 250 it is an excellent target for atmospheric characterization. The six warm Jupiters, with
equilibrium temperatures of 377-846 K, are low-irradiation
benchmarks for hot-Jupiter inflation models. TOI-7025 b has an eccentricity of 0.82 +/- 0.02, one of the largest known for a
planet orbiting a single
star. Finally, using Gaia astrometric excess noise, we detect TOI-5906 B, the first object identified by transit, RV, and astrometry.
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All authors N. Heidari, G. Hébrard, S. Sousa, T. Forveille, F. Destriez, J. D. Eastman, J. M. Almenara, D. W. Latham, B. S. Safonov, R. Brahm, K. G. Stassun, K. A. Collins, D. Dragomir, J. Janík, I. Boisse, J. G. Barrientos, J. Serrano Bell, F. Kiefer, A. Bieryla, X. Bonfils, Z. Balkóová, G. Conzo, M. Deleuil, O. D. S. Demangeon, X. Delfosse, R. F. Díaz, Z. Essack, J. Eberhardt, Y. N. E. Eschen, A. C. Frommer, F. R. Frustagia, D. Feliz, A. F. Gupta, N. Hara, T. Henning, S. B. Howell, A. Jordán, J. Köhler, J. F. Kielkopf, H. A. Knutson, J. Lipták, C. R. Mann, E. Martioli, C. Moutou, F. Murgas, B. Nicholson, P. Pintr, M. Tala Pinto, S. N. Quinn, H. M. Relles, P. Rowden, R. P. Schwarz, R. Sefako, A. Shporer, G. Srdoc, C. Stockdale, I. A. Strakhov, B. Skinner, B. M. Tofflemire, T. Trifonov, S. Ulmer-Moll, L. Vanzi, F. P. Wilkin, C. Ziegler
Cosmology and Nongalactic Astrophysics
Stochastic effect on ultralight dark matter searches with astronomical polarized sources
Kyohei Yamada
Ultralight
axion-like particles (ALP) are the well-motivated candidates for the dark matter. In the standard
halo model, the ultralight galactic dark matter behaves as a
stochastic Gaussian random field, and the polarization angle of the linearly polarized light propagating through the field stochastically oscillates proportional to the field difference between the observer and the source. The statistics of this signal depend on the source size and its distance from the observer relative to the ALP Compton length and coherence length, and therefore on the ALP mass. We present a unified statistical framework for the polarization-oscillation searches with light sources of arbitrary size and distance. We classify the statistics of the
stochastic oscillation amplitude into four distinct regimes and provide a seamless description including the transitional regimes between them. Our framework reproduces the signal models in previously known cases including the laboratory-scale searches and searches using
pulsars and the
cosmic microwave background. We provide a likelihood prescription that incorporates the stochasticity of the signal, and show that uncertainties in source distance must be carefully accounted for, as they can alter the resulting constraints on the ALP-
photon coupling by up to a factor of three. Our results provide a consistent basis for interpreting and comparing a broad range of ALP searches with astronomical polarized sources.
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Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Universal Relations Meet Causality: Bounding the Dynamical Love Number of Neutron Stars
Alex Kehagias and Antonio Riotto
The frequency-dependent tidal response of a
neutron star is constrained by causality, reality and passivity, which turn a suitably rescaled response into a holomorphic self-map of the upper complex frequency half-plane after some suitable conditions. The Schwarz–Pick
theorem then bounds the leading dynamical correction to the tidal deformability from above. In this work we confront this bound with the most recent calculations of the dynamical tidal response in the literature which have also shown that the static tidal deformability and its correction at second order in frequency are tightly correlated. We find that the bound is saturated to within a few per cent, a quantitative confirmation of f-mode dominance in the relativistic regime. The combination of the static deformability with an independent determination of the f-mode frequency thus may provide an equation-of-state-independent upper limit on the dynamical tide.
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High Energy Astrophysical Phenomena
Assessing transitional pulsar candidates through a quantitative estimation of their light-curve similarity
D. F. Torres, C. R. García, F. Coti Zelati et al. (+5 more)
Transitional millisecond
pulsars are often identified through X-ray light-curve morphology, especially by visual comparison with the prototype PSR J1023+0038. Such classifications remain qualitative and lack a calibrated notion of how much variability is already present within the prototype itself. We introduce a Dynamic Time Warping (DTW) framework that compares light curves through moving-window similarity distributions and calibrates candidate-prototype distances against the internal heterogeneity of PSR J1023+0038. In this formulation, a source is not simply asked to resemble one prototype observation, but to remain compatible with the range of morphologies exhibited by the prototype across observations. We apply the method to confirmed and candidate tMSPs and to a control sample of non-tMSP systems. The resulting similarity measure provides a reproducible ranking for tMSP-like behaviour and is therefore useful for candidate triage and archival searches. At the same time, the control sample shows that short-timescale
accretion variability can partly mimic tMSP-like morphology, demonstrating that light-curve shape alone is a screening diagnostic rather than a definitive class identifier.
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All authors D. F. Torres, C. R. García, F. Coti Zelati, D. de Martino, G. Illiano, A. Papitto, A. Patruno, M. C. Baglio
High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Line-of-Sight Acceleration-driven waveform corrections for unequal-mass compact binary coalescences
Mohd Asim Ansari, Avinash Tiwari, Sajad A. Bhat et al. (+2 more)
A constant line-of-sight acceleration (LOSA) of the centre-of-mass of a quasi-circular compact binary coalescence (CBC) leads to modulations in the gravitational-wave (GW) waveform at $-4$ post-Newtonian (PN) order. In our previous work, we calculated the phase and amplitude corrections only for the $(\ell,m) = (2,2)$ mode. The gravitational wave event GW190814 has recently attracted considerable
attention because it has been suggested to provide evidence for a nonzero LOSA. However, several LOSA analyses of GW190814 employ higher-order-mode waveform models, such as IMRPhenomXPHM, while incorporating LOSA corrections only for the dominant (2,2) mode. This approximation assumes that their omission has a negligible impact on parameter estimation. In this paper, we present a self-consistent implementation of LOSA in a higher-mode waveform model by deriving the corresponding phase and amplitude corrections. We show that these corrections are essential for asymmetric binaries such as GW190814 and that neglecting them biases parameter inference. We also discuss inconsistencies in the derivation and implementation of LOSA corrections in waveform models in the literature that include higher-order modes.
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All authors Mohd Asim Ansari, Avinash Tiwari, Sajad A. Bhat, Aditya Vijaykumar, Shasvath J. Kapadia
Solar and Stellar Astrophysics
Mapping of interstellar ices with JWST in protostellar envelopes: Spatial variations of $^{13}$CO$_2$, $^{12}$CO$_2$, CO, OCN$^-$ and H$_2$O ice
N. G. C. Brunken, E. F. van Dishoeck, A. C. A. Boogert et al. (+16 more)
The composition of
planets and their atmospheres is largely determined by the formation environment of the
planet. This environment is pre-determined during early stages when the protostar is still forming. Charting the structure of protostellar envelopes is therefore crucial for understanding how the chemistry is linked to the physical processes occurring in stellar nurseries. We use JWST NIRSpec IFU observations to extract spectra at every pixel in the IFU and map the distribution of $^{13}$CO$_2$,$^{12}$CO$_2$, CO, OCN$^-$ and H$_2$O ice. The 13CO2 ice feature, a known thermal tracer, is also used to identify high-temperature regions where the ices are thermally processed. The findings show that the distribution of ices in both L1527 and IRAS 20126+4104 is not uniform, with both envelopes showing localized temperature zones and substructures. In L1527, CO$_2$ ice segregation and OCN$^-$ enhancement with respect to CO$_2$ are observed in the warm central disk region close to the protostar. In IRAS 20126+4104, the warm temperature zones are observed mostly towards the shocked region in the NW outflow where dense material is interacting with the precessing jet as well as close to the central source. The CO$_2$ ice is segregated at these locations and we observe sublimation of CO ice. In addition, crystalline H$_2$O ice is detected at a few locations in the envelope. In both low mass and high mass protostar the findings indicate that the distribution of ices and their structure are linked to the temperature structure of the envelopes. The envelope of IRAS 20126 shows a more complex structure, where interacting material results in localized regions of high temperatures and denser regions that harbor cooler ices. L1527 in contrast appears to be a more structured system with heated warm ices observed mostly towards the central disk regions.
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All authors N. G. C. Brunken, E. F. van Dishoeck, A. C. A. Boogert, P. Nazari, Y. Chen, J. Santos, H. Beuther, A. Caratti o Garatti, T. Megeath, K. Slavicinska, C. Gieser, H. Tyagi, L. Tychoniec, M. McClure, V. J. M. le Gouellec, Y. Yang, L. W. Looney, N. J. Evans, M. Narang
High Energy Astrophysical Phenomena
The Potential Contribution of Radiative Supernova Remnants to the Local Cosmic Ray Spectrum
P. Cristofari, V. H. M. Phan, S. Recchia et al. (+1 more)
Recent observations of very-high-energy gamma rays from massive stellar clusters and microquasars have demonstrated that these systems can efficiently accelerate particles to very high energies, renewing the debate on the dominant sources of Galactic
cosmic rays (CRs) and casting further doubt on the role of
supernova remnants (SNRs), long considered the
prime candidates. In these astrophysical environments, particle acceleration is generally thought to be driven by diffusive shock acceleration (DSA). The question of the duration of the phase in which DSA can efficiently take place is therefore essential to clarify the contribution of the various candidate CR sources. We aim at clarifying the contribution of SNRs to the Galactic CR spectrum, and the expected efficiency of DSA, especially accounting for possible particle acceleration during part of the radiative phase. We compute the total CR
proton content at typical SNRs from DSA and reaccelerated pre-existing CRs, and discuss the importance of these two mechanisms throughout the adiabatic and early radiative phases. We find that if DSA and reacceleration take place during a fraction of the radiative phase, the total content of particles energized at SNRs can quickly overcome the typical budget required to account for the bulk of CRs. This suggests that the typical instantaneous efficiency, often defined as the fraction of fluid ram pressure converted into CRs would need to remain below $\lesssim 1$% for most of the SNR
evolution. Moreover, the radiative phase can contribute to shaping the spectra injected from typical SNRs. We illustrate that the difference between SNRs from thermonuclear and core-collapse SNe could help account for the measured difference in the helium and
proton of the local interstellar spectrum.
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All authors P. Cristofari, V. H. M. Phan, S. Recchia, S. Gabici
Earth and Planetary Astrophysics
Reflex instabilities II: The reflex motion of the central object drives at least seven instabilities in accretion discs
Nathan Magnan, Michel Tagger, Clément Baruteau et al. (+3 more)
This series of papers studies the stability of
accretion discs to the reflex motion of the central object under the gravitational pull of the disc itself. In this second paper, we use linear analysis to reproduce or discover seven distinct instabilities. We outline their defining characteristics and propose a classification. Of the four instabilities that had already been discovered, three are artificial: one does not survive the transition to modern surface density profiles such as power-laws, one is due to the location of the domain's boundaries, and one is due to the use of damping layers near the domain's boundaries. Only the SLING instability of Adams et al. (1989) and the three new 'cavity' instabilities seem capable of affecting
accretion discs. All four can be described to a high degree of precision by WKB methods. They may drive eccentricity growth, affect
planet migration, create spiral and crescent substructures in the absence of any
planet, and boost
accretion onto the central object. The issue is that the three artificial instabilities are extremely hard to avoid in simulations, and would bias the same observables. This suggests that our community may not have the tools to model the reflex motion of the central object yet.
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All authors Nathan Magnan, Michel Tagger, Clément Baruteau, Aurélien Crida, Jean-François Gonzalez, Héloïse Méheut
Earth and Planetary Astrophysics
Reflex instabilities I: Boundaries makes grid-based disc simulations frame-dependent
Nathan Magnan, Michel Tagger, Clément Baruteau et al. (+3 more)
If the mass distribution within an
accretion disc is asymmetric, it will exert a gravitational pull on its central object. The central object must then move away from the origin of the reference frame, resulting in atypical gravitational pulls on the disc. The goal of the present series of papers is to investigate the stability of this feedback loop. In this first paper, we report a surprising finding: the choice of reference frame affects the number and nature of the waves and instabilities contained in the analytical equations. To show this, we use a simple example: the modes discovered by Sanchez et al. (2025, Appendix A.3). We provide the first analytical description of those modes, we explain their physical mechanism, and propose to call them 'bracket modes' because they arise from the bracket side of an integration by parts. We show that the same disc can be stable in the stellocentric reference frame but unstable in the barycentric reference frame. This is because the boundaries of the simulation domain are frame-dependent. To avoid this, one must model the entire disc all the way from the central cavity to the outer edge. But this is prohibitively expensive, and some discs do not have a central cavity anyway. Our results suggest that extreme caution is required when interpreting simulations of asymmetric discs, and that our community may not have the tools to model the reflex motion of the central object yet.
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All authors Nathan Magnan, Michel Tagger, Clément Baruteau, Aurélien Crida, Jean-François Gonzalez, Héloïse Méheut
High Energy Astrophysical Phenomena
Predicting High-Energy neutrino emission from X-ray absorption in CSM-interacting SNe
Silvia Gagliardini, Simone Dall'Osso and Dafne Guetta
Core-collapse
supernovae (CCSNe) interacting with a dense circumstellar medium (CSM) are promising sources of high-energy
neutrinos. Most
neutrino predictions rely on specific assumptions about the CSM density profile and progenitor mass-loss history. We develop a data-driven framework that connects X-ray observations directly to the expected
neutrino signal. Using the temporal
evolution of the hydrogen-equivalent absorbing column density, N_H(t), together with the shock velocity inferred from the X-ray
plasma temperature, we reconstruct the CSM density profile and shock velocity
evolution. We estimate the shock-breakout (SBO) epoch and the resulting
neutrino emission, and apply the method to the nearby interacting
supernovae SN 2023ixf and SN 2024ggi. For both sources, we compute the expected
neutrino event rates for IceCube and KM3NeT/ARCA. We find that
neutrino production is concentrated near SBO, when hadronic interactions are most efficient. This naturally defines a short time window, specific to each source, that maximizes the signal-to-background ratio. Our results demonstrate that X-ray observations can constrain at once both the expected
neutrino signal and the optimal time window for its detection, providing an observationally-driven strategy for multimessenger searches of these shock-powered transients.
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High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Line-of-sight Acceleration Driven Effects in Eccentric Compact Binary Coalescences
Mohd Asim Ansari, Avinash Tiwari, Sajad A. Bhat et al. (+2 more)
The line-of-sight acceleration (LOSA) effect, imprinted in the gravitational wave (GW) signal of an inspiralling compact binary by an external gravitational potential, is one of the most promising means of probing the environment of compact binaries on a single-event basis. However, this effect is potentially degenerate with other low-frequency effects, particularly the binary's orbital eccentricity. LOSA effects and orbital eccentricity can mimic each other if only one or the other (but not both) are accounted for in the waveform template. In this work, we present the (2, 2) mode, leading eccentric harmonic, frequency-domain phase correction incurred by an accelerating eccentric compact binary, and discuss inconsistencies pertaining to this phase correction in the literature. We show that the degeneracy between LOSA and orbital eccentricity can be resolved if both effects are modeled in the template. To demonstrate this, we inject a GW170817-like signal, with eccentricity and LOSA added to it, and recover the parameters of the injected signal assuming an A+ like noise power spectral density (PSD) of the LVK detector network. We find that the true LOSA and eccentricity parameters, along with other binary parameters, are recovered within the $90\%$ credible interval (CI). This study highlights the importance of incorporating LOSA in eccentric waveform models to robustly and reliably estimate LOSA and eccentricity.
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All authors Mohd Asim Ansari, Avinash Tiwari, Sajad A. Bhat, Sreejith Nair, Shasvath J. Kapadia
Instrumentation and Methods for Astrophysics
Rapid Sequence Cost Evaluation for Multi-Spacecraft Rendezvous: A Permutation-Invariant Set Transformer
An-yi Huang
Multi-spacecraft multi-rendezvous mission design requires repeated evaluations of the total cost of visiting a target set within a given time window, and the efficiency of this evaluation is the primary barrier to global search. Existing methods either optimize the order and epochs of each candidate sequence, which is expensive, or estimate the cost leg by leg, in which case the error accumulates with the sequence length. This paper proposes a deep model that regresses the total cost of an unordered target set directly: the pairwise transfer cost surface of each target pair is compressed into a latent feature, and a permutation-invariant
transformer encoder regresses the sequence cost from these features and the window parameters, without ordering information. Trained on about 0.85 million labeled sequences, the model attains a mean relative error near 5% and a sub-millisecond evaluation time, about five orders of magnitude faster than precise optimization. Embedded into an evolutionary global search and applied to the GTOC9 problem, it yields the best known solution at every fleet size considered, from seven to ten spacecraft: directly, it produces near-optimal solutions cheaply, and as the initial guess of a differential-
evolution refinement it improves the best published solutions further. The evaluator is not specific to this problem or to debris removal: it requires only a pairwise transfer cost function and a sequence-level cost metric monotone in the leg costs, and therefore applies equally to the servicing of satellites in low Earth orbit and to multi-target visits in deep space.
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Cosmology and Nongalactic Astrophysics
The impact of feedback and cosmology on Cosmic Infrared Background cross-correlations
Sara Maleubre, David Alonso, Reggie Dunsdon et al. (+3 more)
We study the
evolution and clustering properties of the
star formation rate density (SFR) $\rho_{\rm SFR}$ in the FLAMINGO suite of hydrodynamical simulations, with the aim of exploring the possibility of constraining AGN and stellar feedback prescription, as well as the effect of cosmology, using cross-correlations between the
Cosmic Infrared Background (CIB) and other tracers of the large-scale structure. Specifically, we consider tomographic measurements of the bias-weighted SFR-density $\langle b\rho_{\rm SFR}\rangle$, as well as cross-correlations between the CIB and
cosmic shear as a probe of the $\rho_{\rm SFR}$-matter correlation. Most of the FLAMINGO models calibrated against the $z=0$
galaxy stellar mass function (SMF) yield similar predictions for the distribution and clustering of
star-forming systems, and thus it is difficult to derive clean conclusions regarding the impact of AGN feedback or cosmology on CIB statistics. However, we show that current measurements of $\langle b\rho_{\rm SFR}\rangle$, as well as CIB-shear cross-correlations clearly disfavour models with strong stellar feedback, as well as simulations with strong kinetic (jet-driven) AGN feedback, even under the fiducial SMF calibration. This study demonstrates the potential of CIB cross-correlations to study aspects of the physics of
star and
galaxy formation in a cosmological setting.
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All authors Sara Maleubre, David Alonso, Reggie Dunsdon, Adrien La Posta, Amy Wayland, Joop Schaye
Astrophysics of Galaxies
The $\mathrm{[O\ III]}\lambda5007$ Equivalent Width as an Ionization-Parameter Diagnostic Across Cosmic Time
Dian P. Triani and Lisa J. Kewley
Nebular emission lines and stellar continua probe the conditions of $\mathrm{H\ II}$ regions. The optical emission line $\mathrm{[O\ III]}\lambda 5007$ is important because it is observable across a wide
redshift range, enabling studies of interstellar medium (ISM) conditions across
cosmic time. We investigate the equivalent width of $\mathrm{[O\ III]}\lambda 5007$ (EWO3) as an ionization-parameter diagnostic, providing an alternative to the $\mathrm{[O\ III]} \lambda 5007 / \mathrm{[O\ II]} \lambda 3727$ (O32) ratio, which requires broad wavelength coverage and dust corrections that may not be available at high
redshift. We employ the MAPPINGS photoionization code with input spectra from BPASS, comparing single-
star and binary-inclusive stellar populations. We find that binary-inclusive populations sustain harder ionizing spectra and strong $\mathrm{[O\ III]}\lambda 5007$ emission to later ages than single-
star populations. EWO3 is highly sensitive to the ionization parameter and exhibits systematic dependencies on
metallicity, gas pressure, and stellar population age. While these dependencies broadly follow those of O32, EWO3 is less sensitive to gas pressure in the low-
metallicity, high-ionization regime, making EWO3 well suited for studies of metal-poor and high-
redshift galaxies. Comparing the models with observations, we find that local
galaxies are reproduced by lower-pressure models, whereas intermediate- and high-
redshift galaxies require higher gas pressures, indicating evolving ISM conditions across
cosmic time. We present
metallicity- and pressure-dependent calibrations of EWO3 as an ionization-parameter diagnostic. When validated against ionization parameters derived from O32, the $\log(P/k)=6$ calibration provides the best agreement for local
galaxies, while the $\log(P/k)=7$ calibration best reproduces intermediate- and high-
redshift galaxies.
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Earth and Planetary Astrophysics · Cross-listed from cs.CV
Decoy and disclosure radii of invariant shape descriptors
Tanush Shaska and Lubjana Beshaj
A recognizer that compares rotation-invariant descriptors sees a surface only up to the fiber of the descriptor. We measure this fiber by its radius in the orbit distance from the enrolled surface. A large radius admits decoys, that is, distant shapes that pass the matcher. A small radius discloses the enrolled shape to anyone who captures the stored value. For
star-shaped surfaces truncated to spherical harmonics of degree at most $L$, with $n$ coefficients, a descriptor of generic rank $r$ has generic fibers of dimension $n-3-r$ modulo rotations. The standard pool of band powers, even bispectra, and three invariants of the degree-three band therefore admits decoy families of dimension $5$, $13$, $20$ at $L=4,6,8$. Its rank first reaches $n-3$ at $L=16$, and a mirror decoy remains at every $L$. The odd bispectra remove the mirror decoy generically for $L \geq 4$. Yet at fixed mean radius the same pool determines the enclosed volume exactly, and it does not determine whether a surface meets a clearance requirement. We certify two cases by exact and interval arithmetic. At $L=6$ a decoy matches all $32$ invariants to relative precision $2 \cdot 10^{-18}$ at orbit distance at least $0.87$ times the norm of the enrolled tuple. For the radar shape model of asteroid (101955) Bennu, the pool recovers the modeled volume, misses the handedness, and leaves the keep-out radius uncertain by more than $7 \, \mathrm{m}$.
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Cosmology and Nongalactic Astrophysics
ApPolLO: Apertif counterparts of Polarised LOFAR sources
A. Berger, B. Adebahr, H. Dénes et al. (+1 more)
Knowledge of the structure and
evolution of
cosmic magnetic fields is indispensable to understand how primordial
magnetic fields were generated and amplified during the lifetime of the Universe. Polarisation studies over significant
redshift ranges are an important tool in understanding
cosmic magnetic fields. We aim to understand the structure and
evolution of
cosmic magnetic fields, utilising the polarised spectra and depolarisation characteristics of (background)
radio sources. Using
radio polarisation data at two different frequencies from the LOFAR Rotation Measure (RM) grid catalogue at 144\,MHz and new Apertif data at 1.4\,GHz, we investigate the source statistics of a common sample of polarised sources, deriving the depolarisation ratio between these two frequencies. We utilise this to disentangle depolarising effects local to the source from those along the line of sight. We compile a catalogue of 598 polarised
radio components, most of which are located in low-density environments. Fractional polarisation decrease for both wavelengths with
redshift. We attributed the main depolarisation at 1.4\,GHz to effects occurring close to the sources, while the depolarisation measured at 144\,MHz is most likely generated by
cosmic filaments along the line-of-sight. We were able to get a first
redshift dependent upper limit estimate of the RM dispersion in
cosmic web filaments.
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All authors A. Berger, B. Adebahr, H. Dénes, R.-J. Dettmar
High Energy Astrophysical Phenomena
Probing turbulence in the ionized interstellar medium using young pulsars. I. Dispersion measure variations
S. J. I. Melfor, A. Parthasarathy, S. Johnston et al. (+9 more)
Temporal variations in the dispersion measure (DM) of
pulsars probe fluctuations in the free-electron density of the ionized interstellar medium (IISM). While DM variations have been studied extensively in millisecond
pulsars, young
pulsars provide a complementary probe due to their lines of sight (LoSs) intersecting
supernova remnants,
pulsar wind nebulae, and other turbulent environments. However, systematic studies of DM variability in young
pulsars remain limited. In this paper, We characterize the temporal DM variations of a large population of young
pulsars to constrain the
turbulence of the IISM along their LoSs and to investigate the physical origins of the observed variability. We analyzed 18 years of timing observations of 364 young
pulsars obtained with the Murriyang/Parkes
radio telescope, combining legacy data from the 21 cm Multibeam receiver with recent observations from the ultra-wideband low-frequency (UWL) receiver. Epoch-wise DM measurements were derived from sub-banded times of arrival, and the variability was characterized using linear trends and DM structure functions, which were compared with expectations for a Kolmogorov
turbulence. Significant DM variations are detected in 89
pulsars in the UWL data and in 23
pulsars in the multibeam data, with 16 in the combined
dataset showing significant trends. This represents one of the largest long-baseline studies of DM variability in
pulsars. We find tentative evidence that the observed DM variations are predominantly consistent with Kolmogorov
turbulence. PSRs J1105-6107 and J1829-1751 show estimated DM variations driven by periodic profile variability. We also identify 21 bright, slow
pulsars exhibiting short-term DM variations that exceed expectations from the IISM.
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All authors S. J. I. Melfor, A. Parthasarathy, S. Johnston, A. Chalumeau, S. Dai, M. Kerr, M. E. Lower, R. N. Manchester, L. S. Oswald, S. Roch, C. A. Sobey, P. Weltevrede
High Energy Astrophysical Phenomena
X-ray spectral scaling of black hole mass in quasi-periodic eruptive source RX J1301.9+2747
Lev Titarchuk, Elena Seifina, Vadim Arefiev et al. (+2 more)
We present a spectral and timing analysis of X-ray emission from the actively accreting supermassive black hole (SMBH) in RX~J1301.9+2747 with prominent quasi-periodic eruptions (QPEs) using ASCA, ROSAT, XMM-Newton, and NICER observations. NICER detected renewed QPE activity from this source in 2024. We examined in detail the X-ray spectrum formation in this source during QPE outbursts applying the first-principal model, Bulk Motion Comptonization. We find an increase of the
photon index $\Gamma$ with a mass
accretion rate $\dot M$, the index saturation at $\Gamma_{sat}=2.7\pm 0.1$ at high $\dot M$ value during outburst peaks. Based on the derived $\Gamma-\dot M$ correlation, we apply the scaling technique for the first time to measure the black hole mass in RX~J1301.9+2747. The SMBH mass in this source was estimated to be between $4\times 10^5$ M$_ {\odot}$ and $7\times 10^6$ M$_ {\odot}$ for the inclination range from 0$^{\circ}$ to 70$^{\circ}$, which is adopted as a plausible range based on the AGN unified model assumption, applying HLX–1~ESO 243–49, OJ~287, and 1H~0707–495 as reference scaling sources. We also estimate a BH mass in RX~J1301.9+2747 applying a timing analysis, in which the Compton cloud size to be $\sim 10^{11}$ cm, estimated from the quasi-periodic oscillation frequency, $\nu\sim 10^{-4}$ Hz, indicates SMBH mass in RX~J1301.9+2747 is of order of $10^6$ M$_{\odot}$. Overall, the BH mass obtained by the scaling method in this source is consistent with previous measurements using other methods.
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All authors Lev Titarchuk, Elena Seifina, Vadim Arefiev, Diana Makhinya, Alexei Le
Earth and Planetary Astrophysics
Blinding Lights: Simulation-Based Evidence for Terrestrial Giant Impacts as Astronomically Observable Events
Lucy Taylor, Simon J. Lock, Philip J. Carter et al. (+1 more)
Giant impacts (collisions between
planet-sized bodies) are violent events that fundamentally alter the properties of
planets and the structure of planetary systems. Observations of these events provide important constraints on the role of giant impacts in the formation of planetary systems. However, relating such observations to the specifics of the impact responsible is challenging, since numerical simulations struggle to resolve the expected extreme low densities of observable material at the edge of ongoing impact structures. In particular, lower limits on density are often enforced in SPH codes for computational efficiency. Here, we present a method of post-processing output from smoothed particle hydrodynamics (SPH) simulations of giant impacts, that emulates realistic physical properties in multi-phase and multi-material collisions, in order to better understand these low-density outer regions. We apply our novel post-processing pipeline to determine the direct thermal emission and potential observational signatures of giant impacts, and obtain consistent photic surface geometries for an example impact simulated for a range of resolutions and code parameters. We find that during the first days after this terrestrial giant impact event, the emission from hot, unbound ejecta can be comparable in temperature and luminosity to that of an M-Dwarf
star, and as such can be astronomically observable. Our work begins to bridge the gap between observations and theoretical models, and could allow high cadence, large-sky surveys, such as that to be carried out by the Vera C. Rubin Observatory, to place constraints on the frequency and properties of giant impacts in our local neighbourhood.
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All authors Lucy Taylor, Simon J. Lock, Philip J. Carter, Zoë M. Leinhardt
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Gravitational Waves and Nambu-Goldstone Bosons from Infrared-Finite Cosmic Strings
Hajime Fukuda, Shuailiang Ge and Keisuke Harigaya
Skyrmion lines and semi-local strings are examples of infrared-finite
cosmic strings that arise in theories with spontaneously broken global
symmetries. Unlike global $U(1)$ strings, they do not support the long-range Nambu-Goldstone
boson (NGB) profile responsible for a logarithmically infrared-divergent string tension. We argue that NGB emission from their low-frequency oscillations is strongly suppressed. Consequently, their gravitational-wave signals may be comparable to those from local strings.
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Solar and Stellar Astrophysics
Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) II. Approach to data reduction and products for line-rich broadband (sub)millimeter spectra
Adele L. Plunkett, Sébastien Maret, Daniel Harsono et al. (+26 more)
Studying the chemical composition of the warm gas surrounding embedded solar-type protostars is one of the areas for which the Atacama Large Millimeter/submillimeter Array (ALMA) is particularly well suited. Recently, the ALMA Large Program “Complex Organic Molecules in Protostars with ALMA Spectral Surveys” (COMPASS) carried out an observing campaign of a sample of 11 protostellar regions to investigate the chemical impact of their environments and evolutionary stages. The aim of this paper is to provide the observational and procedural information necessary for the community to understand the analysis presented in forthcoming scientific papers by the COMPASS collaboration, and to enable archival research using the data products provided by our team and the ALMA Science Archive. This paper describes the technical setup of the observations, and it outlines the data-processing pipeline and primary data products from this initiative. The Common Astronomy Software Applications (CASA) was used for initial calibration following the standard ALMA Pipeline, and then IMAGER was used for self-calibration and imaging. We describe post-processing done with Python to achieve favorable continuum subtraction, correct for the primary beam response, and extract spectra. We discuss our strategy for mitigating data challenges, including those related to data volume and continuum subtraction for spectral line analysis. The incorporation of IMAGER in our workflow was advantageous in terms of the computing efficiency which allowed us to
benchmark several imaging parameters and techniques; we also demonstrate that the imaging outcomes using IMAGER or CASA are scientifically comparable. Numerous data products are generated for the program, including image cubes for the 36 spectral windows targeting each source, extracted spectra, and continuum images.
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All authors Adele L. Plunkett, Sébastien Maret, Daniel Harsono, Jes K. Jørgensen, Audrey Coutens, Maria N. Drozdovskaya, Jeong-Eun Lee, Arnaud Belloche, Fernando Cruz-Sáenz de Miera, Merel L. R. van 't Hoff, Jae-Hong Jeong, Chul-Hwan Kim, Ágnes Kóspál, Martine Lützen, Brett A. McGuire, Pooneh Nazari, Silvia Spezzano, Zoie Telkamp, Yao-Lun Yang, Hyeong-Sik Yun, Audrey Andreu, Jennifer Bergner, Judit Ferrer Asensio, Niels F. W. Ligterink, Yuxin Lin, Sheng-Yuan Liu, Pierre Marchand, Mihika Rao, Shaoshan Zeng
Solar and Stellar Astrophysics
Starspots on weak-lined T Tauri stars in the sigma Orionis cluster
Andrew J. Wilson, Darryl J. Sergison, Tim Naylor et al. (+1 more)
The light curves and spectra of T Tauri
stars indicate the presence of cool starspots covering large areas of their photospheres. Heavily spotted
stars should have a larger mid-infrared flux than the equivalent single-temperature photospheres. To test this prediction we first fit single and two-temperature models to optical spectra of young
stars in the 4 Myr-old sigma Orionis cluster and a control set of older field
stars. The fits to the young
stars favour two temperatures while the field
stars show no preference. Independent tests of our models for nine probable single K-type weak-lined T Tauri
stars using infrared photometry confirms the presence of large cool components. We consider and rule out as explanations of the two temperature photospheres: binary
stars for all but one WTTS;
accretion, as the observed H-alpha equivalent width is too small;
gravity darkening as the predicted temperature differences are too small. This leaves cool areas akin to starspots covering 30-95 per cent of the surface as the plausible explanation. Our results show no significant difference in the cool temperature for surface fractions between 0.30-0.75, implying a common mechanism is responsible. These cool surface fractions would lead to significant overestimates in age and mass when fitting unspotted isochrones in colour-magnitude diagrams. The dispersion in cool surface fraction could also explain the dispersion in lithium equivalent width seen in the spectra of coeval zero-age main sequence
stars.
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All authors Andrew J. Wilson, Darryl J. Sergison, Tim Naylor, Robin D. Jeffries
Cosmology and Nongalactic Astrophysics
Evolution of neutrino distributions under repeated electron scattering
Jens Chluba, Bryce Cyr, Michiru Uwabo-Niibo et al. (+1 more)
We study the energy redistribution of
neutrinos by repeated elastic scattering with an isotropic thermal bath of free electrons. Starting from the relevant Boltzmann collision integral, we formulate the
evolution equations in terms of the
neutrino–electron redistribution kernel derived in our companion work. The scattering kernel formulation retains recoil, relativistic kinematics and Pauli blocking, while reducing the calculation to a one-dimensional integral in the outgoing
neutrino energy. To gain a better analytic understanding, we derive the corresponding Fokker–Planck (FP) limit of the collision operator in two independent ways and contrast it with the Kompaneets equation for
photons. This shows that the different energy dependence of the weak cross section changes the drift and
diffusion operators which causes the high-energy part of a
neutrino distribution to evolve much faster than its low-energy part. We discuss the fermionic analogues of temperature-, chemical-potential- and $y$-type spectral distortions, and give approximate analytic solutions to the FP equation in several limiting cases. We also derive the analytic expressions for the relativistic scattering operator when Doppler terms dominate, allowing us to compute the relativistic Sunyaev-Zeldovich equivalent for
neutrinos in the inefficient scattering limit. We compare these expressions to the full numerical result based on the detailed collision term. Finally, we set up conservative numerical schemes for both the FP equation and the scattering kernel, generalizing previous codes developed for studying the repeated Compton scattering of
photons by relativistic electrons. Controlled line-injection experiments then illustrate when the
diffusion approximation is accurate and where the non-locality of the redistribution kernel remains essential.
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All authors Jens Chluba, Bryce Cyr, Michiru Uwabo-Niibo, Masahide Yamaguchi
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Flavor decoherence and washout timing in nonthermal leptogenesis after inflation
Boliang Yu and Ruixin Zhou
We investigate why changing the heavy-
neutrino mass hierarchy can reverse the baryon asymmetry in nonthermal leptogenesis after hilltop inflation. Along the mass trajectory studied here, lowering the mass of the lighter state, \(N_1\), reverses the final asymmetry while leaving the dominant injection from \(N_2\) decays nearly unchanged. The mass change primarily delays \(N_1\) washout relative to electron–
muon flavor decoherence; at fixed source and background, translating the washout history while preserving its shape and integrated strength reproduces more than 99% of the yield changes from the nonthermal \(N_2\) source at two physical target masses. Decomposing the \(N_2\) CP source shows that the projector-aligned component remains positive under both washout histories, whereas the initially trace-free component reverses its propagated contribution and accounts for about 99.7% of the timing contrast in the fixed-source comparison. Rapid damping of \(e\mu\) flavor coherence largely removes this contrast, while rapid chemical equilibration does not. Later washout therefore acts on a more decohered flavor state, reducing the positive \(e\mu\) contribution and allowing negative diagonal contributions to determine the final sign. At a mass recomputed to reproduce the observed baryon yield, a 10% increase of the
muon collision operator reverses the sign in a fixed-input sensitivity test.
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Astrophysics of Galaxies
Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) VI. Discovery of a class I methanol maser transition and its association with acetaldehyde
Jae-Hong Jeong, Jeong-Eun Lee, Jes K. Jørgensen et al. (+16 more)
CH3OH masers that are collisionally pumped, referred to as `class I', commonly trace shock interfaces in
star-forming regions, but their incidence in low-mass protostars remains poorly quantified. We use data from the COMPASS ALMA Large Program to establish the occurrence, spatial origin, and excitation of a newly detected class I CH3OH maser at 302.9 GHz towards low-mass protostars and to test whether its pumping environments exhibit signatures of shock-driven complex chemistry. COMPASS provides unbiased line surveys of 11 sources between 279.0 and 311.7 GHz at typical angular resolutions of 0.3"-0.5". Rotation diagram analysis of departures from LTE in the 302.9 GHz CH3OH excitation robustly reveals masing in seven of 11 sources, with peak brightness temperatures from a few to ~10^3 K. The brightest detection is towards HOPS 108 and is likely associated with the powerful outflow from the nearby intermediate-mass protostar HOPS 370. Excluding this case, the maser is detected in six of ten low-mass protostars (60%). All six are Class 0 sources interacting with dense ambient material, whereas the non-detections comprise three Class I sources and one isolated Class 0 core, indicating a preference for early evolutionary stages and gas-rich environments for outflow-ambient medium interactions. The maser emission is spatially coincident with thermal CH3OH along outflow cavity walls and bow shocks, but is more compact and
knot-like. Among the surveyed COMs, only CH3CHO closely traces the shocked morphology of the 302.9 GHz maser, and only around HOPS 108. These results show that class I CH3OH masers in low-mass protostellar systems are more prevalent than previously recognised and preferentially occur in younger, more embedded sources. More sensitive CH3CHO observations are needed to test whether a similar relationship with shock-driven chemistry also applies in the low-mass regime.
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All authors Jae-Hong Jeong, Jeong-Eun Lee, Jes K. Jørgensen, Audrey Coutens, Maria N. Drozdovskaya, Adele L. Plunkett, Arnaud Belloche, Sébastien Maret, Hyeong-Sik Yun, Fernando Cruz-Sáenz de Miera, Daniel Harsono, Merel L. R. van 't Hoff, Chul-Hwan Kim, Ágnes Kóspál, Brett A. McGuire, Pooneh Nazari, Silvia Spezzano, Yao-Lun Yang, Shaoshan Zeng
High Energy Astrophysical Phenomena · Cross-listed from hep-ph
Clément Ehrhardt, Maria Cristina Volpe, Miguel Ángel Aloy et al. (+1 more)
Despite several decades of searches, the
neutrino magnetic moment remains unknown. If it is large, the
neutrino evolution can be affected by its coupling to strong
magnetic fields like the ones present in at least some core-collapse
supernovae. We explore these effects for Majorana
neutrinos. We first discuss a schematic model often employed and show the impact of resonant
spin-flavor precession on the
neutrino signal for a future galactic
supernova. Then, we consider detailed simulations of a
neutrino-driven
supernova with 17 ${\rm M}_{\odot}$ leaving a
neutron star and a magnetorotational
supernova with 26 ${\rm M}_{\odot}$ with a black-hole remnant. We present predictions for the
supernova neutrino fluxes and the event rates in presence of a non-zero
neutrino magnetic moment, for the running JUNO and upcoming Hyper-Kamiokande experiments. Our results show a significant impact for transition
magnetic moments of $10^{-14} ~\mu_B$ during the neutronization burst and the
accretion phase for the
neutrino driven
supernova, and as small as $10^{-15} ~\mu_B$ at the early times for the magnetorotational
supernova.
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All authors Clément Ehrhardt, Maria Cristina Volpe, Miguel Ángel Aloy, Martin Obergaulinger
Earth and Planetary Astrophysics
Ariel Tier 3 Observations: An Opportunity to Explore both Stellar and Planetary Variability through Broad Wavelength Time-domain Spectroscopy
Alexandra H. Thompson, Quentin Changeat, Theresa Luftinger et al. (+1 more)
Ariel's Tier 3 observing strategy offers a unique opportunity to explore planetary and stellar variability in the spectral and time domain. However, without the correct toolkit, temporal variability of the host
star may complicate combined analysesof observations obtained at different epochs. We investigate the impact of stellar variability on Ariel Tier 3 observations and establish three different mitigation approaches of increasing physical complexity. Using simulated repeated observations of a favourable system contaminated by different spot and facula configurations, we compare a naive, unmodified stacking approach, separate analysis of the infrared region through progressive removal of the most strongly contaminated optical wavelengths, and the correction of individual visits using combined
star-
planet retrievals. We find that stacking inconsistent visits can produce substantial biases in the retrieved planetary properties under strong stellar variability, although a single activity correction can still recover the planetary parameters reasonably well. Applying progressive optical data cuts substantially improves the accuracy of
retrievals up to a point, without requiring any in-
retrieval correction and causing only a modest loss of precision. Correcting individual visits prior to stacking produces more consistent spectra and generally smaller uncertainties, but requires greater computational effort. These results demonstrate that stellar variability should be considered when interpreting repeated Ariel observations, but need not preclude atmospheric characterisation of active systems. A flexible suite of mitigation approaches, supported by preparatory and contemporaneous stellar monitoring, can allow the treatment of stellar variability to be adapted to individual targets while maintaining the efficiency required to maximise Ariel's scientific return.
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All authors Alexandra H. Thompson, Quentin Changeat, Theresa Luftinger, Giovanna Tinetti
Solar and Stellar Astrophysics
Exploring an X1.8 flare and associated quasi-periodic pulsations using SDO and Aditya-L1 observations, alongside NFFF extrapolation
Pawan Kumar, Sanjay Kumar, Sadashiv et al. (+2 more)
The paper seeks to explore the initiation of an X1.8 class solar
flare (SOL2024-10-09T0124) and the related quasi-periodic pulsations (QPPs), which are situated within NOAA active region 13848. To achieve this, we perform a multi-wavelength analysis of the event utilizing data from the Solar Dynamic Observatory (SDO) and Aditya-L1. Importantly, the observations indicate the emergence of a sigmoidal brightening at the onset of the
flare, alongside the
evolution of a complex morphology of
flare brightenings and ribbons around the peak time of the
flare. Furthermore, QPPs are detected during the impulsive phase of the
flare, exhibiting a dominant period of approximately 4 minutes in the hard X-ray light curve. In order to comprehend the initiation of the
flare, we construct the coronal
magnetic field at a pre-
flare stage by employing the non-force-free-field (NFFF) extrapolation model. The extrapolated
magnetic field illustrates the existence of various significant
magnetic features, including a
magnetic flux rope, a three-dimensional (3D) null, sheared arcade, and quasi- separatrix layers (QSLs) within the flaring region. The recurrent reconnection occurring at these features is proposed to play a role in the initiation of the
flare as well as the associated QPPs.
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All authors Pawan Kumar, Sanjay Kumar, Sadashiv, Sachin Rajkapoor Kanaujiya, Yogesh Kumar Maurya