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Physics Astrophysics

astro-ph Watch Astrophysics

Monday 23 March

Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc

Cosmological coupled black holes immersed in dark sector

Chen-Hao Wu, Yue Chu and Ya-Peng Hu

Motivated by theoretical and observational developments of cosmological coupled black holes, we construct an exact analytical solution for a black hole immersed in an anisotropic dark sector background, adopting the framework established by [Cadoni et al., JCAP 03 (2024) 026]. By generalizing a static seed metric to a dynamical FLRW background, we derive a solution where the black hole mass co-evolves with the cosmic expansion. We then obtain the explicit form of the radius-dependent coupling exponent, revealing that the interaction is governed by the dark halo profile. Considering the ubiquity of the dark halos surrounding supermassive black holes, our model provides a potential realization of cosmological coupling, interpreting the mass growth as the dynamical response of the surrounding dark sector fluid to the Hubble flow, distinct from the method of modifying the black hole's internal equation of state.
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Earth and Planetary Astrophysics

A Physical Classification of Exoplanet Thermal Environments: Stellar Irradiation versus Tidal Heating

Daniel Fadrique Barbero

In this study, we introduce a physical framework to analyse and classify the thermal regimes governed by tidal heating and stellar irradiation. Although all planetary systems are exposed to stellar radiation, this source is not always the dominant energy mechanism. This study is motivated by the lack of a physical framework that examines tidal heating in cases where this phenomenon dominates over stellar irradiation. We develop a reproducible physical approach that allows us to classify the relative contribution of both fluxes in a population of exoplanets, identifying the most relevant physical mechanisms that determine the thermal regime. We apply this method to a population of approximately 2000 exoplanets. This framework is centred on the dimensionless parameter \(\Lambda=F_{\mathrm{abs}}/F_{\mathrm{tide}}\), which quantifies the relative contribution of each flux. Our results show that most planetary thermal environments are dominated by \(F_{\mathrm{abs}}\), although there is a significant fraction of systems in which the tidal flux dominates. We identify a physical boundary at \(\Lambda=1\) that defines a regime in which both fluxes are comparable. We identify the semi-major axis \(a\) and the eccentricity \(e\) are the parameters that most influence the tidal flux. This framework provides a transparent and physically motivated tool for characterising planetary thermal environments and exploring the physical trends governing exoplanet populations.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Dark graviton sensing with magnetically levitated superconductors

Valentina Danieli, Paola C. M. Delgado and Federico R. Urban

Levitated sensors have emerged as a new frontier to detect ultra-light dark matter such as axion-like particles and dark photons. In this work we study how a magnetically levitated superconductor responds to a spin-2 dark matter field, the dark graviton, in the dHz to kHz frequency range. To do so, we compute the forces that the dark graviton exerts on the superconductor, separately for matter and light couplings. The matter coupling produces a strain-like tidal acceleration between the superconductor and the centre of mass of the rigid apparatus, resulting in a displacement relative to the readout pick-up loop, in a way analogous to the response to a slow, continuous, massive gravitational wave. The light coupling instead induces an effective current that sources an oscillating magnetic field, thus driving the superdiamagnetic response of the superconductor. We find that, albeit with significant experimental improvements, the sensitivity reach for the matter coupling could surpass existing fifth-force experiments in the audio frequency band. At the same time, magnetically levitated superconductors could be among the most sensitive laboratory probes of the dark-graviton coupling to electromagnetism, especially at low frequencies, provided technical and readout noise can be kept under control.
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Earth and Planetary Astrophysics

Multi-Sensor Trajectory Reconstruction of the 24 April 2025 Alaska Fireball and Implications for Planetary Defense

L. T. Scamfer, E. A. Silber, M.D. Fries et al. (+6 more)

On 24 April 2025 at 18:30:57 UTC, a bright daytime fireball over Southcentral Alaska was detected by 37 seismic stations, 16 single infrasound sensors, and four infrasound arrays, yielding 30 ballistic and multiple fragmentation arrivals. The unprecedented density of seismoacoustic coverage enabled detailed reconstruction of the event using acoustic signals, with fragmentation source locations further guiding the identification of Doppler weather radar signatures of a meteorite fall. Incorporation of a radar-derived terminal point yielded a final trajectory solution, which agreed closely with an independent optical trajectory solution from video analysis. The reconstructed entry parameters from seismoacoustic analysis indicate a velocity of 25.3 km/s, an entry angle of 19{\deg}, and an energy release of ~38 t TNT equivalent. Assuming a chondritic composition, the pre-entry object diameter was ~0.7 m. Using orbital parameters from the optical solution, we estimate meteoroid composition as most likely a L-type ordinary chondrite. The event occurred in the sub-Arctic, where space-based optical systems face challenges in detection, demonstrating the critical role of dense ground-based seismoacoustic networks in characterizing highlatitude atmospheric entries. This uniquely well-recorded event demonstrates the capability of dense seismoacoustic networks to constrain bolide trajectories, energetics, and fragmentation, with radar and optical data providing critical confirmation and complementary perspectives. These results bridge the methodological gap between planetary-defense monitoring of natural impactors and space-traffic analyses of artificial reentries, illustrating how multi-sensor integration can deliver calibration-grade trajectories even for unpredicted events.
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All authors L. T. Scamfer, E. A. Silber, M.D. Fries, D. Vida, D. Šegon, P. Jenniskens, Y. Nishikawa, V. Sawal, T. A. Rector

Solar and Stellar Astrophysics · Cross-listed from physics.plasm-ph

Wave-particle equilibria with heavy ions in weakly collisional space plasmas

Nicolás Villarroel-Sepúlveda, Daniel Verscharen, Pablo S. Moya et al. (+2 more)

Space plasmas are weakly collisional since characteristic time scales related to Coulomb collisions are much larger than those of Larmor gyration or wave–particle interactions. Thus, wave activity is likely to drive some of the non-thermal features that are observed in space plasma velocity distributions, such as temperature anisotropy, beams, and skewness. Therefore, we study how wave–particle interactions shape the velocity distribution functions of minor ions, and how these ions and their statistical properties modify the dispersion relation of electromagnetic waves. To achieve this, we derive the motion of heavy ions in electromagnetic waves using the Boris algorithm. We take the waves to be solutions of the fully kinetic dispersion relation of electromagnetic waves in two-ion component plasmas with parameters representative of the solar wind. We use the Arbitrary Linear Plasma Solver (ALPS) code to derive the linear Vlasov–Maxwell dispersion relation based on the actual distribution of the ions. The test-particles are initially in thermal equilibrium, and their distribution evolves due to interactions with the waves. By solving the dispersion relation using the evolved distributions, we show that the system evolves into a steady wave–particle equilibrium, which is characterized by a minimization of the interaction and energy transfer between wave and particles.
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All authors Nicolás Villarroel-Sepúlveda, Daniel Verscharen, Pablo S. Moya, Rodrigo A. López, Kristopher G. Klein

Earth and Planetary Astrophysics

Subsurface ocean salinity and dissipation rate inferred from Enceladus ice shell morphology

Wanying Kang and Yixiao Zhang

The habitability of Enceladus' subsurface ocean and the detectability of potential biosignatures depend on efficient ocean circulation and suitable ocean conditions. Directly probing the ocean is challenging because it lies beneath a thick ice shell; however, the ice thickness distribution is relatively well constrained and provides indirect insight into the underlying ocean dynamics. This study investigates how ocean circulation and the associated heat transport depend on ocean salinity and tide-induced vertical mixing using scaling analysis, supported by numerical simulations. We find that ocean circulation and equatorward heat convergence are stronger under extremely high or low salinity conditions than under intermediate salinity, and both increase with tidal mixing rates. Because the poleward thinning of Enceladus' ice shell cannot be maintained in the presence of strong equatorward ocean heat transport, these results place constraints on the ocean salinity, diffusivity, circulation timescale, and ocean dissipation rate. Energetic analysis further shows that Enceladus' ocean behaves like an extremely efficient heat pump (inefficient heat engine), potentially transporting up to 1000 times more heat across latitudes than the energy dissipated within the ocean itself, thereby placing strong constraints on the ocean's energy dissipation rate.
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Instrumentation and Methods for Astrophysics

The Radio-wave Observations at the Lunar Surface of the photoElectron Sheath (ROLSES) instrument onboard the Intuitive Machines-1 Mission to the Moon

Nat Gopalswamy, Robert J. MacDowall, Pertti A. Mäkelä et al. (+15 more)

The Radio wave Observations at the Lunar Surface of the photoElectron Sheath (ROLSES) instrument is a radio telescope system designed to characterize the radio and plasma wave environment of the nearside lunar surface at frequencies between 2 kHz and 30 MHz. The ROLSES sensor consists of a set of four 2.5 meter radio monopole antennas onboard the Intuitive Machines (IM 1) lander, Odysseus. The antennas were stowed during launch and deployed after landing on the lunar surface using a frangibolt mechanism. The frequency range is well suited to observing radio waves at frequencies below 15 MHz that cannot be observed from Earth due to the ionospheric cutoff. Radio waves from the Sun, the Milky Way galaxy, Jupiter, Earth's auroral region, and ground-based radio transmitters were expected to be present on the lunar surface. Radio data from each of the 4 antennas, after passing through an isolating pre-amp and signal conditioning analog electronics, were digitized to 14 bits at 120 mega samples per second and then digitally processed by a Field Programmable Gate Array (FPGA) that performs onboard spectral analysis via a Fast Fourier Transform (FFT). Time averaged spectral values are then stored and returned. Also telemetered to Earth are raw waveforms (unprocessed time sequence data) that are useful in studying dust impact on ROLSES antennas. ROLSES data are sent to the lander and subsequently downlinked for further processing. ROLSES is part of NASA's Commercial Lunar Payload Services (CLPS) program. Odysseus landed close to the south pole at Malapert A (80 S). This paper describes the design and operations of the ROLSES instrument and presents initial observations made during transit and surface operations despite the tilted landing of Odysseus. We also describe next version of this instrument (ROLSES 2) currently under development.
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All authors Nat Gopalswamy, Robert J. MacDowall, Pertti A. Mäkelä, Scott A. Boardsen, Seiji Yashiro, Richard B. Katz, Igor Kleyner, Scott D. Murphy, Richard C. Mills, Chimaobi Onyeachu, Michael K. Choi, Thomas M. Schluszas, Victor Gonzalez-leon, Pietro A. Sparacino, William M. Farrell, Damon C. Bradley, Jack O. Burns, Joshua J. Hibbard

Earth and Planetary Astrophysics

Automatic search for transiting planets in TESS-SPOC FFIs with RAVEN: over 100 newly validated planets and over 2000 vetted candidates

M. Lafarga, D. J. Armstrong, K. Cui et al. (+7 more)

Space-based missions such as TESS are identifying a wealth of short-period ($\lesssim30$ d) transiting planets. Despite the growing number of confirmed and candidate planets, the sample is still incomplete and highly biased, challenging demographic studies. Moreover, there are still a large number of unconfirmed candidates that can end up being false positives. We use the new pipeline RAVEN to perform a uniform search and validation of transiting planet candidates in TESS data. We focus on a magnitude-limited sample of over 2.2 million main sequence stars well characterised by Gaia and observed by TESS in its Full Frame Images during its first 4 years of operations (sectors 1 to 55). We aim to detect candidates with periods within $0.5-16$ days. RAVEN detects candidates with a box least squares algorithm, classifies them into transiting planets and false positives using machine learning models trained with realistic simulations, and performs statistical validation. We present several samples of candidates with different levels of vetting and validation. We newly validate 118 planets, including 31 newly detected here. We also present a sample of over 2000 candidates not validated but with high probability of being planets, including $\sim1000$ new candidates, a small sample of newly identified mono- and duo-transiting candidates, and a sample of large radii ($>8~\mathrm{R_{\oplus}}$) candidates with high planet probability suited for further follow-up. Our samples of vetted and validated transiting planet candidates represent a major effort towards improving the candidate sample from TESS.
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All authors M. Lafarga, D. J. Armstrong, K. Cui, A. Hadjigeorghiou, V. Kunovac, L. Doyle, E. M. Bryant, R. F. Díaz, L. A. Nieto, A. Osborn

High Energy Astrophysical Phenomena

A Multi-messenger Search for Ultra-high-energy Gamma Rays in Coincidence with Neutrinos

R. Alfaro, C. Alvarez, A. Andrés et al. (+101 more)

The last five years have shown us that ultra-high-energy (UHE; $>$100 TeV) gamma-ray sources are ubiquitous, but the nature of these sources remain highly uncertain. UHE gamma rays can be produced via either leptonic (Inverse compton) or hadronic (pion decay) emission mechanisms. To decisively determine the emission mechanisms, multimessenger searches are essential. Neutrinos are of particular interest as they are only created via hadronic channels. In this work, we describe a metric to select high-quality UHE events from the High Altitude Water Cherenkov (HAWC) Observatory. We use this metric to search for correlations between HAWC archival data and IceCube public neutrino alerts. 24 spatial coincidences are found, which is higher than the number of events expected by random chance. Therefore, we conclude that there are likely associations between HAWC gamma rays and IceCube neutrinos, but the angular resolutions of the two instruments prevent us from conclusively making any definitive associations between the coincidences and specific astrophysical sources. More sensitive detectors are needed.
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All authors R. Alfaro, C. Alvarez, A. Andrés, E. Anita-Rangel, M. Araya, J.C. Arteaga-Velázquez, D. Avila Rojas, H.A. Ayala Solares, R. Babu, P. Bangale, E. Belmont-Moreno, A. Bernal, K.S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, C. de León, P. Desiati, N. Di Lalla, R. Diaz Hernandez, M.A. DuVernois, J.C. Díaz-Vélez, K. Engel, T. Ergin, C. Espinoza, K. Fang, N. Fraija, S. Fraija, A. Galván-Gámez, J.A. García-González, F. Garfias, N. Ghosh, M.M. González, J.A. González, J.A. Goodman, S. Groetsch, D. Guevel, J. Gyeong, J.P. Harding, S. Hernández-Cadena, I. Herzog, J. Hinton, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, S. Kaufmann, A. Lara, K. Leavitt, J. Lee, T. Lewis, H. León Vargas, J.T. Linnemann, A.L. Longinotti, G. Luis-Raya, K. Malone, M. Martin, O. Martinez, J. Martínez-Castro, J.A. Matthews, P. Miranda-Romagnoli, P.E. Mirón-Enriquez, J.A. Morales-Soto, E. Moreno, M. Mostafá, M. Najafi, A. Nayerhoda, L. Nellen, N. Omodei, M. Osorio-Archila, E. Ponce, Y. Pérez Araujo, E.G. Pérez-Pérez, C.D. Rho, A. Rodriguez Parra, D. Rosa-González, M. Roth, H. Salazar, D. Salazar-Gallegos, A. Sandoval, M. Schneider, J. Serna-Franco, M. Shin, A.J. Smith, Y. Son, R.W. Springer, O. Tibolla, K. Tollefson, I. Torres, R. Torres-Escobedo, E. Varela, L. Villaseñor, X. Wang, Z. Wang, I.J. Watson, H. Wu, S. Yu, S. Yun-Cárcamo, X. Zhang, H. Zhou

Instrumentation and Methods for Astrophysics

Dimpled scalar vortex coronagraph laboratory demonstration

Niyati Desai, Garreth Ruane, Susan Redmond et al. (+3 more)

Achieving the Habitable Worlds Observatory (HWO) goal of 10^-10 contrast at a separation of 3 $\lambda$/D across a 20% bandwidth requires coronagraph focal plane masks with both broadband high contrast performance and high planet throughput. Scalar vortex coronagraphs (SVCs) offer a promising alternative to polarization-sensitive vector vortex designs but face chromatic limitations. This work presents the latest laboratory demonstrations of second-generation scalar vortex prototypes that incorporate radial phase dimples to improve broadband starlight suppression. We compare these new "dimpled" sawtooth masks to previous-generation scalar designs through high-contrast imaging experiments on the In-Air Coronagraph Testbed. Using electric field conjugation, we achieve near testbed-limited contrasts across both narrow (2%) and broadband (10%) spectral ranges. We report the best in-air contrasts achieved to date for scalar vortex masks across narrow and broadband spectral ranges and we also show that the dimpled vortex predicted bench-limited contrast performances for 2%, 10% and 18% bandwidths agree with the measured lab contrasts within a factor of two. These results highlight the potential of topographically achromatized scalar vortex masks as candidates for future space-based high-contrast imaging missions and mark a significant step toward polarization-independent coronagraphs capable of meeting HWO performance requirements.
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All authors Niyati Desai, Garreth Ruane, Susan Redmond, Dimitri Mawet, Eugene Serabyn, Bertrand Mennesson

Earth and Planetary Astrophysics

Turning the knobs on dust evolution: Comparing codes, parameters and their effects on planet formation and disc observables

Linn E. J. Eriksson, Thomas Pfeil, Nicolas Kaufmann et al. (+1 more)

Protoplanetary discs contain a wide range of dust sizes that influence their thermal structure and planet formation processes such as planetesimal formation and pebble accretion. Dust evolution models are therefore essential for both planet formation simulations and the interpretation of disc observations. Several open-source dust evolution codes are available, each adopting different model assumptions. We present a comparison of 1D radial simulations using (in order of complexity) two-pop-py, TriPoD, and DustPy, and 2D radial-vertical simulations with TriPoD, cuDisc, and mcdust. The comparison includes dust size distributions, dust disc masses, planetary gap structures, millimetre fluxes and disc sizes from synthetic observations, planetesimal formation regions, and planetary growth via pebble accretion. We also perform a parameter study to assess how key dust-evolution parameters influence disc evolution, planet formation, and code agreement. In 1D, two-pop-py depletes dust masses faster and produces higher dust concentrations outside planetary gaps than DustPy or TriPoD. The latter two generally agree well, except when size distributions deviate strongly from a power law. While the calculated millimetre fluxes and disc radii agree well, planetesimal formation locations and pebble accretion rates vary significantly between codes. In 2D, we compare cuDisc, mcdust, and TriPoD in simulations of turbulence- and sedimentation-driven coagulation. The dust size distributions agree well, despite the completely different numerical approaches used to model dust coagulation. The largest differences arise in the upper atmosphere, where mcdust suffers from low mass resolution and TriPoD fails to reproduce the exact shape of size distributions that deviate from a power-law.
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All authors Linn E. J. Eriksson, Thomas Pfeil, Nicolas Kaufmann, Vignesh Vaikundaraman

High Energy Astrophysical Phenomena · Cross-listed from nucl-ex

First measurements of deuteron production spectra in p+p collisions at beam momentum of 158 GeV/c at NA61/SHINE

Anirvan Shukla

The NA61/SHINE spectrometer at the CERN Super Proton Synchrotron (SPS) scans particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range towards various physics goals. This paper presents the first differential production measurements of deuterons at energies relevant for cosmic-ray studies, produced in inelastic p+p interactions at incident projectile momentum of 158 GeV/c ($\sqrt{s}$ = 17.3 GeV). The double-differential spectra are presented as functions of rapidity and transverse momentum and are compared to predictions of the thermal and coalescence models. These measurements are essential for improving our understanding of cosmic (anti)nuclei production, as detecting cosmic antinuclei can be a breakthrough approach to identifying dark matter. The primary source of cosmic antinuclei background is interactions between cosmic-ray protons and interstellar hydrogen gas. Gaining a deeper insight into the deuteron production mechanism in p+p interactions is an essential first step in modeling cosmic antinuclei production.
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Instrumentation and Methods for Astrophysics

Model validation and tolerancing of scalar vortex masks in the High Contrast Imaging Testbed (HCIT) facility

Niyati Desai, Garreth Ruane, Daniel Shanks et al. (+3 more)

The Habitable Worlds Observatory (HWO) mission will require coronagraphs capable of suppressing starlight at the $\sim 10^{-10}$ contrast level to directly image exo-Earths. High contrast achromatic coronagraphic masks are the missing critical component to achieving this. Vortex coronagraphs, particularly scalar vortex designs with an achromatic focal plane mask, offer key advantages. While all vortex coronagraph varieties provide high throughput, a small inner working angle, and rejection of low-order aberrations, the scalar approach enables dual-polarization observation in a single optical path. This simplifies instrument design and increases transmission by maintaining light from the planet in two orthogonal polarization states. In this work we test scalar vortex masks and investigate their contrast limitations. We perform phase metrology to assess the mask defects and manufacturing deviations and use it to refine the coronagraphic model used for electric field conjugation (EFC) algorithms and end-to-end simulations. We also measure the impact of model-mismatch with EFC by varying model parameters including clocking angle, and central wavelength in laboratory demonstrations. Finally, we validate our scalar vortex models against experimental results from the High Contrast Imaging Testbed (HCIT) facility at JPL by finding good agreement between lab and simulated performance. This ultimately helps to benchmark simulated contrast predictions for future scalar vortex coronagraph designs for HWO.
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All authors Niyati Desai, Garreth Ruane, Daniel Shanks, Lorenzo König, Susan Redmond, Bertrand Mennesson

Earth and Planetary Astrophysics

Ecological modelling of hycean worlds

Gregory J. Cooke, Nikku Madhusudhan and Emily G. Mitchell

New observations are opening the possibility of characterising habitable environments in exoplanetary systems, with the recent example of the candidate hycean world K2-18 b. This motivates an exploration of the possible ecological conditions on such planets to better interpret biosignatures as well as understand the nature of potential life. On Earth, the Lotka-Volterra equations have been used to model numerous coupled populations within ecosystems, from interactions between large vertebrates, to systems with multiple microbial species. In this work, we apply the Lotka-Volterra equations to the ecology of habitable exoplanets for the first time, focusing on hycean worlds. We simulate scenarios in a vertical water column with between 1-5 bacterial species that thrive in anoxic environments on Earth, i.e. similar to predicted hycean conditions. We find that a wide range of ecological diversity is possible for microbial populations under hycean conditions. We demonstrate that dominating phototrophic bacteria at the top of a water column out-compete deeper dwelling phototrophic bacteria, analogous to bacterial blooms on Earth. Incorporating microbial viruses (bacteriophages) within our models can cause ecosystem collapse depending on the time of their introduction, and such phage inclusion can be beneficial to ecological diversity. Finally, our work shows that bacterial populations inhabiting tidally locked exoplanets may be more stable due to constant illumination of the ocean, but can have lower peak population densities in such cases when compared to seasonal scenarios. Our work provides an initial step towards understanding the possible ecological diversity on habitable worlds beyond Earth.
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High Energy Astrophysical Phenomena · Cross-listed from hep-ph

Analyzing Fermionic Dark Matter scenarios with anomalous compact objects

Yaiza Cano and Jose Manuel Alarcón

In this paper, we consider three compact objects (HESS J1731-347, PSR J1231-1411, XTE J1814-338) with anomalous mass-radius relation to analyze the possibility of being dark matter admixed neutron stars. We try to infer the dark matter particle properties, under the assumption of behaving as a free Fermi gas. The main novelty relies on the use of a baryonic equation of state obtained from first principles in the whole density range, that allows to eliminate the model dependence of the baryonic part of the calculation. Once the possible Dark Matter Admixed Neutron Star configurations are obtained, we check their stability and whether it is feasible for a Neutron Star to capture the necessary dark matter fraction. We show that two of the anomalous compact objects (HESS J1731-347 and PSR J1231-1411) can be explained with a small fraction of fermionic dark matter content in the star. The other compact object (XTE J1814-338) cannot be explained as a dark matter admixed neutron star, and becomes a potential candidate for a twin star.
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Cosmology and Nongalactic Astrophysics

Euclid preparation. XCV. Cosmology Likelihood for Observables in Euclid (CLOE). 2. Code implementation

Euclid Collaboration: S. Joudaki, V. Pettorino, L. Blot et al. (+344 more)

We provide a description of the code implementation and structure of Cosmology Likelihood for Observables in Euclid (CLOE), developed by members of the Euclid Consortium. CLOE is a modular Python code for computing the theoretical predictions of cosmological observables and evaluating them against state-of-the-art data from galaxy surveys such as Euclid in a unified likelihood. This primarily includes the core observables of weak gravitational lensing, photometric galaxy clustering, galaxy-galaxy lensing, and spectroscopic galaxy clustering, but also extended probes such as the clusters of galaxies and cross-correlations of galaxy positions and shapes with the cosmic microwave background. While CLOE has been developed to serve as the unified framework for the parameter inferences in Euclid, it has general capabilities that can serve the broader cosmological community. It is different from other comparable cosmological tools in that it is written entirely in Python, performs the full likelihood calculation, and includes both photometric and spectroscopic observables. We focus on the primary probes of Euclid and describe the overall code structure, rigorous code development practices, extensive documentation, unique features, speed optimization, and future development plans. CLOE is publicly available at https://github.com/cloe-org/cloe.
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All authors Euclid Collaboration: S. Joudaki, V. Pettorino, L. Blot, M. Bonici, S. Camera, G. Cañas-Herrera, V. F. Cardone, P. Carrilho, S. Casas, S. Davini, S. Di Domizio, S. Farrens, L. W. K. Goh, S. Gouyou Beauchamps, S. Ilić, F. Keil, A. M. C. Le Brun, M. Martinelli, C. Moretti, A. Pezzotta, Z. Sakr, A. G. Sánchez, D. Sciotti, K. Tanidis, I. Tutusaus, V. Ajani, S. Alvi, M. Crocce, A. C. Deshpande, A. Fumagalli, C. Giocoli, A. G. Ferrari, R. Kou, L. Legrand, M. Lembo, G. F. Lesci, D. Navarro-Gironés, A. Nouri-Zonoz, S. Pamuk, L. Pagano, M. Tsedrik, S. Arcari, E. Artis, M. Ballardini, J. Bel, C. Carbone, M. Costanzi, B. De Caro, C. A. J. Duncan, G. Fabbian, M. Kilbinger, T. Kitching, F. Lacasa, M. Lattanzi, J. Olivares-Miranda, L. Salvati, D. Sapone, B. Sartoris, E. Sellentin, P. L. Taylor, B. Altieri, A. Amara, L. Amendola, S. Andreon, N. Auricchio, C. Baccigalupi, M. Baldi, S. Bardelli, P. Battaglia, A. Biviano, D. Bonino, E. Branchini, M. Brescia, J. Brinchmann, A. Caillat, V. Capobianco, J. Carretero, M. Castellano, G. Castignani, S. Cavuoti, K. C. Chambers, A. Cimatti, C. Colodro-Conde, G. Congedo, C. J. Conselice, L. Conversi, Y. Copin, F. Courbin, H. M. Courtois, A. Da Silva, H. Degaudenzi, S. de la Torre, G. De Lucia, A. M. Di Giorgio, H. Dole, F. Dubath, X. Dupac, S. Dusini, A. Ealet, S. Escoffier, M. Farina, R. Farinelli, F. Faustini, S. Ferriol, F. Finelli, P. Fosalba, S. Fotopoulou, N. Fourmanoit, M. Frailis, E. Franceschi, M. Fumana, S. Galeotta, K. George, W. Gillard, B. Gillis, J. Gracia-Carpio, B. R. Granett, A. Grazian, F. Grupp, L. Guzzo, S. V. H. Haugan, H. Hoekstra, W. Holmes, I. Hook, F. Hormuth, A. Hornstrup, P. Hudelot, K. Jahnke, M. Jhabvala, E. Keihänen, S. Kermiche, A. Kiessling, B. Kubik, K. Kuijken, M. Kümmel, M. Kunz, H. Kurki-Suonio, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, G. Mainetti, D. Maino, E. Maiorano, O. Mansutti, O. Marggraf, N. Martinet, F. Marulli, R. Massey, S. Maurogordato, H. J. McCracken, E. Medinaceli, S. Mei, Y. Mellier, M. Meneghetti, E. Merlin, G. Meylan, A. Mora, M. Moresco, L. Moscardini, S. Mourre, E. Munari, R. Nakajima, C. Neissner, S.-M. Niemi, J. W. Nightingale, C. Padilla, S. Paltani, F. Pasian, K. Pedersen, W. J. Percival, S. Pires, G. Polenta, M. Poncet, L. A. Popa, L. Pozzetti, F. Raison, R. Rebolo, A. Renzi, J. Rhodes, G. Riccio, E. Romelli, M. Roncarelli, R. Saglia, J. A. Schewtschenko, M. Schirmer, P. Schneider, T. Schrabback, A. Secroun, E. Sefusatti, G. Seidel, M. Seiffert, S. Serrano, P. Simon, C. Sirignano, G. Sirri, A. Spurio Mancini, L. Stanco, J.-L. Starck, J. Steinwagner, P. Tallada-Crespí, A. N. Taylor, I. Tereno, S. Toft, R. Toledo-Moreo, F. Torradeflot, L. Valenziano, J. Valiviita, T. Vassallo, G. Verdoes Kleijn, A. Veropalumbo, Y. Wang, J. Weller, A. Zacchei, G. Zamorani, F. M. Zerbi, E. Zucca, V. Allevato, M. Bolzonella, E. Bozzo, C. Burigana, M. Calabrese, D. Di Ferdinando, J. A. Escartin Vigo, S. Matthew, N. Mauri, R. B. Metcalf, A. A. Nucita, M. Pöntinen, C. Porciani, V. Scottez, M. Tenti, M. Viel, M. Wiesmann, Y. Akrami, I. T. Andika, R. E. Angulo, S. Anselmi, M. Archidiacono, F. Atrio-Barandela, A. Balaguera-Antolinez, M. Bethermin, A. Blanchard, H. Böhringer, S. Borgani, M. L. Brown, S. Bruton, A. Calabro, B. Camacho Quevedo, A. Cappi, F. Caro, C. S. Carvalho, T. Castro, F. Cogato, S. Conseil, S. Contarini, A. R. Cooray, O. Cucciati, F. De Paolis, G. Desprez, A. Díaz-Sánchez, J. M. Diego, P. Dimauro, A. Enia, Y. Fang, P. G. Ferreira, A. Finoguenov, A. Franco, K. Ganga, J. García-Bellido, T. Gasparetto, V. Gautard, R. Gavazzi, E. Gaztanaga, F. Giacomini, F. Gianotti, G. Gozaliasl, M. Guidi, C. M. Gutierrez, A. Hall, S. Hemmati, C. Hernández-Monteagudo, H. Hildebrandt, J. Hjorth, J. J. E. Kajava, Y. Kang, V. Kansal, D. Karagiannis, K. Kiiveri, C. C. Kirkpatrick, S. Kruk, J. Le Graet, F. Lepori, G. Leroy, J. Lesgourgues, L. Leuzzi, T. I. Liaudat, S. J. Liu, A. Loureiro, J. Macias-Perez, G. Maggio, M. Magliocchetti, F. Mannucci, R. Maoli, J. Martín-Fleitas, C. J. A. P. Martins, L. Maurin, M. Migliaccio, M. Miluzio, P. Monaco, G. Morgante, C. Murray, S. Nadathur, K. Naidoo, A. Navarro-Alsina, S. Nesseris, F. Passalacqua, K. Paterson, L. Patrizii, A. Pisani, D. Potter, S. Quai, M. Radovich, P. Reimberg, I. Risso, P.-F. Rocci, S. Sacquegna, M. Sahlén, E. Sarpa, J. Schaye, A. Schneider, M. Sereno, A. Silvestri, L. C. Smith, J. Stadel, C. Tao, G. Testera, R. Teyssier, S. Tosi, A. Troja, M. Tucci, C. Valieri, A. Venhola, D. Vergani, F. Vernizzi, G. Verza, N. A. Walton

Solar and Stellar Astrophysics

Optical Spectroscopy of the IR Source CPM 19 and Surrounding Objects

T.Yu. Magakian, T.A. Movsessian, A.V. Moiseev et al. (+2 more)

Optical spectra of the well-known infrared source CPM~19, which exhibited a strong decline in brightness during the period from 1984–1987 to 2000–2005, have been obtained for the first time. A strong and broad H$\alpha$ emission line has been detected, along with the possible presence of [S II] emission. No traces of an absorption spectrum are observed. It is suggested that the optical component of CPM 19 is in the pre-main-sequence stage. Various explanations of the observed properties are considered; a plausible scenario is that CPM 19 may belong to the class of UX Ori-type stars with an unusually long eclipse duration, similar to that observed in V1184 Tau. Spectra of other nebulous objects in the vicinity of CPM 19, including the HH objects HH 940 and HH 941, have also been obtained and discussed.
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All authors T.Yu. Magakian, T.A. Movsessian, A.V. Moiseev, T.S. Molyarova, R.I. Uklein

High Energy Astrophysical Phenomena

Impact of eccentricity on the population properties of neutron star - black hole mergers

Gonzalo Morras, Geraint Pratten and Patricia Schmidt

We revisit the population properties of neutron star-black hole (NSBH) mergers using low-mass compact binary coalescences reported through GWTC-4. Employing pyEFPE, an inspiral-only waveform model that captures both orbital eccentricity and spin-induced precession, we reanalyse all binary neutron star (BNS) and NSBH events observed via gravitational waves. The BNS systems GW170817 and GW190425 are fully consistent with quasi-circular inspirals, while GW200105 stands out among the NSBH binaries as the only system exhibiting significant residual eccentricity at 20 Hz, strengthening evidence for dynamically driven formation pathways. The remaining NSBH events show no measurable eccentricity and appear broadly compatible with low-spin binaries formed through isolated stellar evolution. Using hierarchical Bayesian inference, we obtain the first joint constraints on the mass, spin, and eccentricity distributions of NSBH binaries. Our results also yield the first simultaneous constraints on spin precession and orbital eccentricity in NSBH mergers, while the inferred merger rates remain fully consistent with previous LVK measurements. Treating all NSBH systems as a single population yields results compatible with formation in hierarchical triples, whereas the quasi-circular population remains broadly consistent with isolated evolution. Our results highlight the emerging role of eccentricity as a key discriminator between formation channels. As the number of NSBH detections grows, joint constraints on masses, spins, and orbital eccentricity will enable increasingly sharp tests of dynamical versus isolated binary evolution, establishing NSBH systems as powerful probes of compact-object astrophysics.
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Cosmology and Nongalactic Astrophysics

Cross-spectra likelihood for robust $\tau$ constraints from all satellite polarisation data

Valentina Genesini, Giacomo Galloni, Luca Pagano et al. (+2 more)

The Thomson scattering optical depth to reionisation, $\tau$, one of the six parameters of the $\Lambda$CDM model, is primarily constrained by the large-scale E-mode polarisation of the Cosmic Microwave Background (CMB). In this work, we present the E-mode Likelihood for Cross-Analysis (elica), a multi-frequency, harmonic-space likelihood that combines all currently available large-scale satellite polarisation data, namely the Planck LFI 70 GHz channel, the Planck HFI 100 and 143 GHz channels processed with the SRoll2 map-making algorithm, and the WMAP Ka, Q, and V bands. The likelihood is built on an extension of the Hamimeche-Lewis formalism to multi-field partial-sky observations. We validate the pipeline using 500 realistic simulations and find that retaining all cross-spectra and the WMAP-LFI auto-spectrum eliminates the significant bias present when all spectra are retained, while preserving comparable uncertainties in the recovered value of $\tau$. From the low-$\ell$ E-mode power spectrum alone, we obtain $\tau = 0.0575_{-0.0058}^{+0.0048}$ (68% CL). Combining elica with the Planck low-$\ell$ temperature likelihood and the CamSpec high-$\ell$ likelihood, we find $\tau = 0.0581_{-0.0059}^{+0.0048}$ and $\ln(10^{10}A_{\mathrm{s}}) = 3.048_{-0.012}^{+0.011}$. Including ACT{} DR6 + Planck CMB lensing and DESI DR2 BAO measurements, we derive an upper bound on the total neutrino mass of $\sum m_\nu < 0.069$ eV (95% CL). Our results, obtained through careful cross-validation of all available large-scale polarisation datasets, robustly confirm that the optical depth remains relatively low. This severely constrains the possibility of explaining, or even significantly reducing, the tension between DESI-BAO and CMB observations with a high value of $\tau$. The elica likelihood is publicly available.
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All authors Valentina Genesini, Giacomo Galloni, Luca Pagano, Paolo Campeti, Massimiliano Lattanzi

Cosmology and Nongalactic Astrophysics

More Than Power: Revisiting the CMB Hemispherical Power Asymmetry with Morphological Descriptors

Javier Carrón Duque, Mikel Martin Barandiaran and Joseba Martínez-Arrizabalaga

The Cosmological Principle assumes a statistically isotropic Universe, but the Cosmic Microwave Background (CMB) exhibits some anomalous statistical features, such as the hemispherical power asymmetry, that challenge this core assumption. We aim to expand the characterization of this anomaly by investigating the uniformity of the CMB's morphological and topological properties, testing whether the asymmetry extends beyond the variance of the temperature field. We evaluate the three Minkowski Functionals (MFs) on local patches of the Planck SMICA temperature map and compare them against realistic simulations. By fitting the local MFs to the analytical expectations for Gaussian isotropic fields, we extract local estimates of the temperature variance, the variance of the field gradients, and the goodness-of-fit. We then evaluate the amplitude and alignment of dipoles in these quantities. We confirm the highly significant variance dipole (p-value $\sim0.3\%-1.0\%$). Furthermore, we report a moderately significant dipole in the gradient variance (p-value $\sim2.6\%-3.7\%$) that is statistically independent of the previous dipole under the $\Lambda$CDM model. We also find a mild spatial variation in the goodness-of-fit to the Gaussian isotropic predictions (p-value $\sim2.1\%-5.6\%$). Remarkably, the Planck dipoles for all three quantities point toward the same region of the sky. We find that the all asymmetries are well described by dipoles. The Hemispherical Asymmetry in the CMB extends beyond its local variance, as we found it to be also present in its local morphology, with a possible hint of non-Gaussianity. These results provide a more complete characterization of the Hemispherical Asymmetry, and will therefore contribute to better determine the nature of the physical effect behind it, whether cosmological, residual foregrounds, or unknown systematics. (Abridged)
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Solar and Stellar Astrophysics

The GRAVITY young stellar object survey – XV. The star-disk interaction region of the T Tauri star DO Tau

GRAVITY Collaboration: K. Perraut, J. Bouvier, H. Nowacki et al. (+60 more)

Protoplanetary disks around young Sun-like stars are the cradles of the vast majority of detected exoplanets. Probing these disks at multiple spatial scales is key to uncovering how planets form. We aim to spatially and spectrally resolve the inner disk and star-disk interaction region of the M0.3 T Tauri star DO Tau by combining two complementary techniques. We used high-resolution near-infrared spectra from CFHT/SPIRou to constrain the magnetospheric star-disk interaction process and optical long-baseline interferometry with ESO VLTI/GRAVITY to determine the sizes of the K-band continuum and Br$\gamma$ line emitting regions. From the SPIRou spectra, we confirmed that this ~0.5 M$_\odot$ star is a strong accretor. The HI and HeI lines exhibit strong variability on a daily timescale, consistent with the burster classification of DO Tau derived from its K2 light curve. We derived an upper limit of 0.35 on the ratio between the magnetospheric truncation radius and the disk corotation radius, indicative of an ordered unstable accretion regime. The size of the Br$\gamma$ line emitting region obtained from GRAVITY is much smaller than the K-band continuum emitting region. This compact Br$\gamma$ emission region ($R_{Br\gamma} \sim$ 0.011 au) suggests that most of the line flux originates from the magnetospheric accretion region and/or from an inner wind close to the magnetosphere-disk interface. The inclination we derived for the inner disk (45-55{\deg}) differs from that of the outer disk inferred from the ALMA continuum (30{\deg}). This points toward a misalignment or warp of the outer disk that may originate from the suspected past encounter with the neighboring HV Tau system.
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All authors GRAVITY Collaboration: K. Perraut, J. Bouvier, H. Nowacki, A. Sousa, M. Houllé, J.F. Donati, E. Alecian, S. Alencar, M. Audard, J.-P. Berger, Y.-I. Bouarour, E. Bordier, G. Bourdarot, A. Carmona, A. Caratti o Garatti, C. Dougados, M. Flock, R. Garcia-Lopez, K. Grankin, A. Kospal, L. Labadie, C. Moutou, J. Sanchez-Bermudez, H. Shang, M. Takami, A. Amorim, W. Brandner, Y. Clénet, R. Davies, R. Dembet, A. Drescher, A. Eckart, F. Eisenhauer, M. Fabricius, H. Feuchtgruber, N.M. Förster-Schreiber, P. Garcia, E. Gendron, R. Genzel, S. Gillessen, T. Henning, L. Jocou, S. Joharle, P. Kervella, L. Kreidberg, S. Lacour, V. Lapeyrère, J.-B. Le Bouquin, D. Lutz, F. Mang, T. Ott, T. Paumard, G. Perrin, S. Rabien, D.C. Ribeiro, M. Sadun Bordoni, D. Santos, J. Shangguan, T. Shimizu, C. Straubmeier, E. Sturm, L. Tacconi, F. Vincent

Astrophysics of Galaxies

Carbon Nitride Monolayer Nanosheets: Astrochemical Insights into the Fate of Interstellar Hydrogen

Dubois David, Guichard Pierre and Pasquier Remi

Ubiquitously found in the Universe, atomic hydrogen represents up to 70% of the neutral gas composition of the Milky Way. As an adatom, hydrogen can physisorb or chemisorb onto interstellar dust grains and icy mantles, thereby contributing to the formation of H2 and, potentially, to the synthesis of more complex hydrogenated species. In addition, structures of relatively large specific surface areas – such as silicates, amorphous carbon, graphene sheets, or water ice-host heterogeneous chemistry that is thought to facilitate the emergence of complex organic matter in astrophysical environments. Although the fundamental physical and chemical processes occurring at dust/gas interfaces are well characterized, current understanding of dust properties governing the formation of H2 and complex molecules remains incomplete. In this context, we introduce graphitic-like two-dimensional carbon nitride monolayer structures (2D-CN) as a putative molecular family of potential relevance to astrochemistry. The physicochemical and electronic properties of these materials have been extensively examined in recent years for industrial and technological applications. Here, we propose that their importance may likewise extend to interstellar and circumstellar environments. To explore this possibility, we employed Density Functional Theory (DFT) calculations to investigate the characteristics and extent of H adsorption onto C2N1, C3N1, C3N2, C3N4, C4N3, C6N6, C6N8, C9N4, and C9N7 monolayer nanosheets. We identify multiple adsorption sites over C-C bonds, above C and N atoms, and hollow (macropore) locations at which energetically favorable binding of atomic hydrogen could occur in the interstellar medium (ISM). From an astrochemical perspective, these 2D-CN structures, if formed, could therefore contribute to the physicochemical processing and evolution of hydrogen in the ISM.
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Solar and Stellar Astrophysics

Magnetic Connectivity in the Time-Dependent Corona and Heliosphere

Roberto Lionello, Cooper Downs, Emily I. Mason et al. (+3 more)

Magnetic flux fills the heliosphere, expands outward from the solar corona, and is fundamentally related to the structure and dynamics of the solar corona and solar wind. Open magnetic flux and the fast wind are thought to originate from open magnetic field lines in coronal holes. Less understood processes in the streamer belt and the boundaries of coronal holes, associated with the more variable slow wind, may be formed by interchange reconnection between open and closed magnetic flux. Interchange reconnection is thought to give rise to field lines that are "folded," i.e. that turn back on themselves. The properties of strahl electrons measured in the solar wind give clues to the heliospheric magnetic connectivity. Unidirectionally outward strahl indicates open field lines, while bidirectional strahl is associated with closed magnetic flux and CMEs. Inward directed, unidirectional strahl is believed to indicate folded flux. We use two time-dependent, flux-evolutionary MHD models of the combined corona and heliosphere, one for a solar-minimum configuration, one for the 2024 total solar eclipse, to investigate the magnetic connectivity of the corona/heliosphere system. We examine how magnetic connectivity varies with distance from the Sun in the two configurations. We evaluate the evolutionary effects by contrasting time-dependent results with the corresponding steady-state calculations, and compare the model connectivities with statistical studies of strahl. The connectivities in the time-evolving simulations are roughly consistent with observed strahl occurrence rates, while those from the steady-state models are not. Our results suggest that complex magnetic connectivities are ubiquitous in the heliosphere.
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All authors Roberto Lionello, Cooper Downs, Emily I. Mason, Jon A. Linker, Pete Riley, Mathew J. Owens

Earth and Planetary Astrophysics

Planet-Planet Scattering Explains the Mass-Eccentricity Relation of Warm Jupiters

Jiayin Dong, Eve J. Lee, Eiichiro Kokubo et al. (+2 more)

Warm giant planets with orbital periods of tens of days exhibit a positive correlation between mass and eccentricity. We interpret this trend as the outcome of planet-planet scattering, representing a transition from collision-dominated interactions among low-mass planets to ejection-dominated interactions among high-mass planets. This framework has important implications for warm Jupiter origins. It suggests that warm Jupiters originate from compact, multi-planet configurations. The dynamical interactions that shape their present-day architectures likely occur near their current semimajor axes, regardless of whether warm Jupiters formed through convergent disk-driven migration or in-situ formation. We argue that several observed properties of warm Jupiter systems, including the eccentricity bimodality, the mass-eccentricity relation, and generally low stellar obliquities, can be explained by this picture. We further predict that not only circular warm Jupiters, but also eccentric warm Jupiters, should frequently have additional planetary companions that are detectable through radial velocity observations. Finally, scattering can produce eccentricities high enough to trigger high-eccentricity tidal migration, potentially explaining the emerging population of proto-hot Jupiters on tidal migration tracks.
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All authors Jiayin Dong, Eve J. Lee, Eiichiro Kokubo, Ruth Murray-Clay, Arvind Gupta

High Energy Astrophysical Phenomena

A large population of over-massive black hole quasars at z=0.3-0.8 revealed by eROSITA

Johannes Buchner, Isabelle Gauger, Qiaoya Wu et al. (+14 more)

In most galaxies, the central black hole accounts for no more than a percent of the total mass in stars. Recently, however, extremely over-massive black holes with ratios of 10% have been reported in dwarf galaxies at z<1 and at cosmic dawn (z>5.5) by JWST. Both findings have been interpreted as signatures of the still mysterious origins of super-massive black holes, such that most of the black hole mass was built at birth rather than through black hole accretion. Here we show that among evolved galaxies over-massive black holes are also present, indicating that overmassive BHs are not a signature unique to black hole formation channels. The first large-area sky survey of the eROSITA X-ray telescope on board SpectrRG identified 200 quasars by their luminous hard X-ray radiation. These signpost rapidly growing black holes. Complementary optical spectroscopy from the Sloan Digital Sky Survey and archival UV to IR photometric data combined with galaxy-quasar decomposition techniques allow us unbiased estimates of cosmological distances, black hole masses and host galaxy stellar masses. We securely identify a sample of over-massive black holes with BH-to-host ratios of more than 5%, which may have undergone exponential accretion spurts lasting about a billion years. Our survey identified a high space density of at least 4/Gpc^3 of overmassive black holes near cosmic noon. This indicates an accretion channel disconnected from the stellar population that cause strong deviations from galaxy scaling relations. This channel is currently not part of galaxy evolution models. The identified channel, if applicable also for the first billion years of cosmic time, can explain JWST AGN without requiring them to signify imprints of black hole seeding mechanism.
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All authors Johannes Buchner, Isabelle Gauger, Qiaoya Wu, Hattie Starck, Catarina Aydar, Yue Shen, Vardha N. Bennert, Kirpal Nandra, Sophia G. H. Waddell, Andrea Merloni, Mara Salvato, Roberto J. Assef, Zsofi Igo, Franz E. Bauer, Dong-Woo Kim, Anton M. Koekemoer, Donald P. Schneider

High Energy Astrophysical Phenomena

The Crimson Kiss of Two Giants: Helium Detonation and High-Energy Neutrino Production

Cecilia Romero Rodríguez and Pau Amaro Seoane

The coalescence of degenerate helium cores during red giant collisions - a process we term erythrohenosis - introduces a novel class of transient astrophysical sources of high-energy neutrinos. Using stellar models generated with MESA and SPH simulations of the final inspiral phase, we develop a semi-analytical model to estimate the amount of hydrogen mixed into the cores, the energy release ($\approx 4.28 \times 10^{49}$ erg) that heats the remnant to $T_f \approx 5.3 \times 10^8$ K, the magnetic field amplification ($B \approx 1.77 \times 10^{10}$ G), and the resulting neutrino flux. We find that the predicted TeV–PeV neutrino signal can account for the diffuse neutrino flux observed by IceCube and demonstrate that a single merger event within $\sim 2$ Mpc would be detectable in this energy regime. Furthermore, we discuss the probability of a magnetized helium flash and assess the subsequent activation of the CNO cycle in the remnant core due to hydrogen mixing. In particular, neutrinos from the decay of $^{18}$F offer a direct observational test of the detonation. The simultaneous emission of high-energy hadronic neutrinos, gravitational waves, and – if the optical depth permits – an electromagnetic signal would constitute a unique multimessenger signature of red giant core collisions, positioning erythrohenosis events as exotic yet potentially observable phenomena in dense stellar systems.
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Astrophysics of Galaxies

CHANG-ES. XXXVIII. A Thin Radio Halo Shaped by Slow Cosmic-Ray Transport in the Quiescent Galaxy NGC 4565

Jianghui Xu, Jiang-Tao Li, Guilin Liu et al. (+11 more)

We present the VLA C-array S-band (2–4 GHz) radio continuum observations of the nearby edge-on spiral galaxy NGC 4565, a target from the Continuum Halos in Nearby Galaxies - an EVLA (CHANG-ES) Survey. We conduct rotation measure synthesis to probe the magnetic field structure and analyze the vertical radio continuum intensity profiles using the 1-D cosmic ray transportation models. The radio continuum emission of NGC 4565 is vertically compact, with a vertical-to-radial extent ratio of $\sim 1/6$. Its vertical profile is optimally described by a two-component Gaussian distribution, yielding a mean Gaussian halo scale height of $\sim 3.0$ kpc. The magnetic field is weak, predominantly disk-parallel, with an equipartition strength of $\lesssim 5\ \mu$G and a rotation measure profile indicative of an axisymmetric spiral structure. Nevertheless, we identify a localized, faint vertical magnetic field component in the northeastern region, hinting at an X-shaped structure that spatially coincides with extraplanar structures detected in H I and soft X-ray emission. The CR transport modeling favors a flux-tube advection scenario, with a slow initial velocity of $v_0 \approx 60$ km s$^{-1}$, consistent with a limited energy input from star formation. Therefore, the absence of an extended radio halo can be explained by the low star formation rate, the weak magnetic field, and the inefficient CR transport. The localized X-shaped field may trace a weak, magnetically guided outflow or a tidal perturbation induced by the nearby companion. NGC 4565 is thus a key quiescent benchmark for understanding the physical conditions required to drive large-scale outflows and generate extended radio halos.
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All authors Jianghui Xu, Jiang-Tao Li, Guilin Liu, Luan Luan, Volker Heesen, Rainer Beck, Judith Irwin, Q. Daniel Wang, Michael Stein, Li-Yuan Lu, Yang Yang, Jeroen Stil, Jayanne English, Ralf-Jürgen Dettmar

Cosmology and Nongalactic Astrophysics

Primordial Non-Gaussianity and the Field-Level Cramer-Rao Bound

Eugene Chen, Daniel Green and Vincent S. H. Lee

Primordial non-Gaussianity is one of the most powerful probes of the inflationary epoch. The particle spectrum relevant to inflation, including masses and spins, is encoded in the precise form of statistical correlations of the adiabatic modes. Yet, in the presence of nonlinear structure formation, the optimal approach to measuring these signals remains unclear. Accurate modeling becomes crucial as late-time non-Gaussianty can become degenerate with primordial physics. Moreover, scale-dependent bias shows that information can move from non-Gaussian initial conditions to the amplitude of the Gaussian fluctuations. In this paper, we aim to clarify how primordial information is encoded in maps of galaxies. We use the field-level Cramer-Rao bound to investigate the ultimate limit of what can be extracted from realistic maps of the Universe. For local non-Gaussianity, we show that multi-tracer scale-dependent bias can exceed the sensitivity of conservative higher-point analyses. However, as expected, the multi-tracer analysis falls short of the optimal constraint when all the modes at the scale of the dark matter halos are included. We then forecast the potential reach of future surveys for equilateral and local non-Gaussianity. Equilateral in particular is highly sensitive to priors and modeling assumptions and can benefit dramatically from theoretical input such as the redshift evolution of the bias.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Inside the Black Box of Big Bang Nucleosynthesis: A Comprehensive Sensitivity Atlas for the Precision Era

Anne-Katherine Burns

In this study we present a comprehensive sensitivity atlas for Big Bang Nucleosynthesis (BBN) in which we quantify the dependence of the primordial abundances of helium-4, deuterium, and lithium-7 as well as $N_{\rm{eff}}$ on variations in 14 fundamental particle physics and cosmological parameters and 63 thermonuclear reaction rates. We use the publicly available BBN code \faGithub \href{https://github.com/vallima/PRyMordial}{\,PRyMordial} to compute each sensitivity using two nuclear reaction rate compilations and two weak-rate normalization schemes, and provide a model independent reference applicable to Beyond the Standard Model (BSM) models in which MeV scale physics is modified. In addition, we rank each parameter's contribution to the theoretical uncertainty budget. We compare our predictions against the latest observational determinations of the primordial abundances, including a recent LBT measurement of the helium-4 abundance \cite{Aver:2026dxv} which roughly halves the observational uncertainty relative to previous determinations. We present these results both fixing $\Delta N_{\rm eff}$ at its Standard Model (SM) value, and allowing it to be a free parameter using the latest uncertainty from the combined CMB+BAO+BBN 2026 value \cite{Goldstein:2026iuu}. When $\Delta N_{\rm eff}$ is allowed to be a free parameter, it dominates the theoretical uncertainty of the helium-4 abundance, highlighting the importance of upcoming observations from the Simons Observatory \cite{SimonsObservatory:2025wwn}. As illustrative applications, we examine the deuterium tension and the Lithium Problem in light of our sensitivity analysis. The full set of numerical results and figures is publicly available on GitHub \faGithub \href{https://github.com/Anne-KatherineBurns/bbn-sensitivity-atlas}{\,bbn-sensitivity-atlas}.
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Astrophysics of Galaxies

A systematic study of AGN feedback in a disk galaxy using MACER II: predictions of X-ray surface brightness profiles and comparison with eROSITA observations

Yuxuan Zou, Feng Yuan, Suoqing Ji et al. (+6 more)

Recently, we have performed a systematic study of AGN feedback in a disk galaxy within the MACER framework. Various model predictions, including the AGN duty cycle, the correlation between black hole accretion rates and star formation rates, and the (cold) gas fraction, have been compared with observations and will be presented in a series of papers. As the second paper in this series, without adjusting any model parameters, we directly use the simulation data introduced in Paper I to compute the predicted X-ray surface brightness profile and compare it with eROSITA observations of circumgalactic medium (CGM) emission around galaxies, which provide important constraints on AGN feedback models. For this comparison, we adopt two stacked eROSITA radial profiles of X-ray surface brightness: (1) distant galaxies with log(M*/M_sun) = 10.5-11.0 at z ~ 0.02-0.10 from Y. Zhang et al. (2024), and (2) nearby L* galaxies within 50 Mpc from L. He and Z. Li (2026). We find that the average simulated profile over time is in good agreement with the stacked measurements of Y. Zhang et al. (2024) over a broad radial range (out to ~100 kpc). Our model predictions also match the results of L. He and Z. Li (2026) at projected radii from ~20 kpc to 120 kpc. While our simulations, which predict only thermal emission, are consistent with these recent X-ray observations, the limitations in our current model mean that this agreement does not preclude a potential contribution from non-thermal emission, for example, from an extended halo of cosmic rays.
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All authors Yuxuan Zou, Feng Yuan, Suoqing Ji, Lin He, Zhiyuan Li, Yi Zhang, Johan Comparat, Zhijie Qu, Taotao Fang