Peer Revenue Publish or profit

Papers

Fresh from arXiv, typeset properly. Highlighted words trade on the market.

Physics Astrophysics

astro-ph Watch Astrophysics

Saturday 11 July

Astrophysics of Galaxies

A UV-to-Near-infrared QSO Composite Spectrum from the SPHEREx All-Sky Survey

Minjin Kim, Yongjung Kim, Woong-Seob Jeong et al. (+19 more)

We present a composite spectrum of $\sim 61,000$ type 1 SDSS QSOs (median $z \approx 1.26$), constructed using SPHEREx spectrophotometric data and covering a rest-frame wavelength range of $0.14-4.5~\mu$m. The SPHEREx mission surveys the entire sky in 102 near-infrared spectral channels spanning $0.75-5.0~\mu$m with a spectral resolution of $R \approx 35-130$, providing a unique dataset for building a statistically robust QSO composite. We find that the UV and optical continuum of the resulting composite can be described by a power law, $f_\nu \propto \nu^{\alpha_\nu}$, with a best-fit spectral index of $\alpha_\nu = -0.10$, while the near-infrared continuum is well-fit with a spectral index of $-1.46$. The power-law indices in both the optical and near-infrared regimes strongly depend on properties of QSOs, such that more luminous QSOs tend to exhibit flatter UV/optical and steeper near-infrared continua compared to those of less luminous ones. The IR-to-optical flux ratio decreases with increasing AGN luminosity, consistent with the predictions of the receding torus model. The line ratios of broad emission lines, including H$\alpha$, Pa$\beta$, and Pa$\alpha$, are in good agreement with predictions from Case B recombination, suggesting that internal extinction is almost negligible. The equivalent widths of these emission lines are proportional to AGN luminosity, contrary to the trend expected from the Baldwin effect. Finally, the shape of the composite is sensitive to host-galaxy contamination, which must be considered when utilizing this QSO composite for subsequent scientific applications.
Read the full abstract

All authors Minjin Kim, Yongjung Kim, Woong-Seob Jeong, Yujin Yang, Jeonghyun Pyo, Richard M. Feder, Bomee Lee, Dohyeong Kim, Kyuseok Oh, Jong-Hak Woo, Jeong Hwan Lee, Yun-Ting Cheng, Yi-Kuan Chiang, Asantha Cooray, Brendan P. Crill, Olivier Dore, Andreas L. Faisst, Zhaoyu Huai, Howard Hui, Daniel C. Masters, Chi H. Nguyen, Michael Zemcov

Solar and Stellar Astrophysics

Effect of Neutron Star Jets on Common Envelope Evolution

Deepanshu Gurjar, Luke Chamandy, Eric G. Blackman et al. (+3 more)

The common envelope (CE) phase is a key stage in binary star evolution that is still not very well understood. Once engulfed by the giant star, the binary companion may accrete envelope material. For neutron star (NS) companions, such accretion may in principle occur at mass rates several orders of magnitude above the Eddington limit and may result in outflows dominated by powerful bi-polar jets with mass-loss rates similar to the accretion rates. Such jets would impact the morphology of the system and the rate of envelope unbinding, which affect the duration and outcome of the CE event. Employing 3D global hydrodynamic simulations, we study the role of such NS jets in a CE event involving a red giant branch star. The jets eventually drill through and break out of the envelope, producing prominent low-density bi-polar lobes. The jets cause about twice as much envelope mass to be unbound ($\sim20\%$ of the envelope) as compared to simulations of the same duration without NS jets ($\sim10\%$). However, the rate of mass unbinding due to the jets decreases towards the ends of the simulations as the jets break out and energetically decouple from the envelope. Moreover, jet activity leads to slightly reduced drag on the binary, decreasing the rate of orbital energy transfer to the envelope. Hence, while such powerful jets can play an important role, negative feedback effects tend to prevent them from dominating envelope unbinding and dictating CE outcomes.
Read the full abstract

All authors Deepanshu Gurjar, Luke Chamandy, Eric G. Blackman, Yangyuxin Zou, Baowei Liu, Jason Nordhaus

Earth and Planetary Astrophysics

High Resolution Optical Methane Linelist from observations of Titan for Cross-Correlation studies

Rafael Rianço-Silva, Pedro Machado, Clara Sousa Silva et al. (+2 more)

Exoplanet atmosphere characterization heavily relies on molecular spectroscopic data. Despite efforts to obtain comprehensive spectral libraries for the chemical characterization of exoplanet atmospheres, large gaps remain, particularly for larger molecules and higher frequencies at high spectral resolution. One key example is the methane (CH4) optical spectrum. CH4, the simplest hydrocarbon, is a crucial species for exoplanet atmosphere characterization and a possible biosignature. However, until now, high-resolution linelists at optical wavelengths for CH4 have been very challenging to obtain either experimentally or computationally, leaving the high resolution spectrum of CH4 uncharacterised across most of the visible spectrum. This restricts exploration of CH4 absorption in the optical regime, as upcoming instruments such as ELT-ANDES and VLT-RISTRETTO will start probing the atmospheres of ever smaller exoplanets in optical wavelengths. To address this spectroscopic data limitation, we observed Titan's optical spectrum, dominated by CH4 absorption, at the highest spectral resolution to date with VLT-ESPRESSO. From it, we produced an empirical, low-temperature high-resolution (R ~ 190000) linelist of CH4 in optical wavelengths which we present here, with thousands of previously unidentified lines. We employ this CH4 linelist (RRS-2026) to build a template suitable for high resolution cross-correlation spectroscopy (HRCCS) studies, a first for CH4 in optical wavelengths. With this new linelist, we performed the first HRCCS detection of CH4 in the atmospheres of Titan and Jupiter using optical high resolution spectra. This work sets the stage for the search for CH4 in exoplanet atmospheres through HRCCS with current and future ground-based high-resolution optical spectrographs, showcasing how Solar System observations provide useful products for exoplanet research.
Read the full abstract

All authors Rafael Rianço-Silva, Pedro Machado, Clara Sousa Silva, Sergey Yurchenko, Giovanna Tinetti

Cosmology and Nongalactic Astrophysics

Dynamics of the inflaton scalar field for a certain class of E-model potentials

Vladimir A. Koutvitsky and Eugene M. Maslov

We investigate the dynamics of the inflaton scalar field in a certain class of inflationary E-models that combine the properties of the Starobinsky model and the $\alpha$-attractor model. The inflaton potential we are dealing with has an exponentially flat plateau at high field values and a sharply defined minimum at zero. Using the slow-roll approximation, we obtain the analytic expressions describing evolution of the background inflaton field at the inflationary stage. To describe the nonlinear field oscillations at the preheating stage, we use the technique of separation of fast (oscillation phase) and slow (field energy density) variables. The obtained expressions are in good agreement with the results of direct numerical integration of the field equations. These expressions are then used to study the evolution of perturbations at the preheating stage. Based on the Mukhanov-Sasaki equation, we derive the Hill equation with slowly varying parameters, which describes the scalar perturbation modes taking into account the anharmonicity of the background oscillations. Using Floquet theory, we analyze the structure of the resonance zones of this equation and then integrate it numerically. We show that the cosmological expansion limits the resonant growth of scalar modes, making their amplitudes nearly constant at late times. We also derive the corresponding Hill equation for tensor modes. We show that resonant amplification of tensor fluctuations of the metric does not occur.
Read the full abstract

Earth and Planetary Astrophysics

Stellar Multiplicity of M Dwarfs with Short-period Giant Planets, and the Characterization of TOI-5628Ab

Tianjun Gan, Alexandrine L'Heureux, Charles Cadieux et al. (+33 more)

Binary stars are ubiquitous, yet it remains unclear how wide-orbit stellar companions influence the formation of hot Jupiters, particularly around M dwarfs. Here, we first report the discovery of TOI-5628Ab, a giant planet transiting a mid-type M dwarf ($M_\ast=0.36\pm0.02\ M_\odot$) every 4.34 days, accompanied by an associated white dwarf TOI-5628B ($M_{\rm WD}=0.59\pm0.16\ M_\odot$) at a projected distance of about 2,500 AU. Using TESS, ground-based photometry and SPIRou RVs, we constrain the planet radius to $0.74\pm0.04\ R_J$ and mass to $0.09\pm0.04\ M_J$, with a $3\sigma$ upper limit of $0.22\ M_J$. Building on this system, we further conduct a homogeneous systematic search for co-moving stellar companions with projected semi-major axis between 100 and 10,000 AU around all M dwarfs with confirmed giant planets with periods smaller than 10 days and radii larger than 0.7 $R_J$, as well as a group of field M stars with stellar properties similar to the planet sample, based on the stellar kinematics from Gaia DR3. We measure a stellar multiplicity of $34.2\pm9.5\%$ for M dwarfs hosting short-period giant planets, which is substantially higher than the fraction of $5.3\pm3.7\%$ for the field M stars by approximately a factor of 6. Our results suggest that wide-orbit stellar companions tend to promote the formation of short-period giant planets around M stars with masses $0.21 \leq M_\ast\leq 0.64\ M_\odot$, and high-eccentricity migration may play an important role in producing such systems.
Read the full abstract

All authors Tianjun Gan, Alexandrine L'Heureux, Charles Cadieux, Shude Mao, Enric Pallé, Sharon X. Wang, Keivan G. Stassun, Steve B. Howell, Benjamin V. Rackham, Steffani M. Grondin, Khalid Barkaoui, Luc Arnold, Étienne Artigau, Artem Burdanov, Adam J. Burgasser, Douglas A. Caldwell, David R. Ciardi, Karen A. Collins, Neil J. Cook, René Doyon, Georgina Dransfield, Akihiko Fukui, Michaël Gillon, Emmanuel Jehin, Felipe Murgas, Norio Narita, Federico R. Noguer, Howard M. Relles, Avi Shporer, Molly N. Simon, Abderahmane Soubkiou, Christopher A. Theissen, Mathilde Timmermans, Amaury H. M. J. Triaud, Robert T. Zellem, S. Zúñiga-Fernández

Earth and Planetary Astrophysics

Parameter estimation from the transit light curve including gravitational lensing effects

Shinta Kasuya, Akihiko Fukui, Ayana Suzuki et al. (+1 more)

We study transit light curves of exoplanets, incorporating gravitational lensing effects, and explore the possibility of estimating planetary masses using only the transit light curve. We analyze existing data for planets with relatively large orbital distances ($>1$ AU) from Kepler and TESS to evaluate how well their masses can be constrained. For six exoplanets, we derive 2$\sigma$ upper limits of 200-2000 Jupiter masses. We also construct mock data to assess the feasibility of determining masses for exoplanets with larger orbital radii than currently known. Our results show that a precision of $3\times 10^{-6}$ is required to recover the true masses of planets with 10 (5) Jupiter masses at orbital radii of $a=20$ (100) AU. Furthermore, we demonstrate that neglecting gravitational effects can lead to underestimation of exoplanet radii, particularly for planets with large orbital separations. Using mock data with a precision of $2\times 10^{-4}$, assuming a 30 minutes cadence with Kepler for a $K_p=14$ mag star, we find that the estimated radii can be underestimated by 1-20% for 5 and 10 Jupiter-mass planets with $a=$ 10-100 AU. These results highlight the importance of including microlensing effects when modeling transit light curves of wide-orbit planets.
Read the full abstract

All authors Shinta Kasuya, Akihiko Fukui, Ayana Suzuki, Naomi Tsuji

High Energy Astrophysical Phenomena

Gaussian-process evidence for a stochastic-variability transition in the recovering corona of 1ES 1927+654

Lijuan Dong and Dahai Yan

We investigate the stochastic X-ray variability of the changing-look active galactic nucleus 1ES 1927+654 during its 2018–2024 evolution, focusing on the recovery of the X-ray corona after its 2018 collapse. Using XMM-Newton EPIC-pn light curves in the 0.3–2.0 keV and 2.0–10.0 keV bands, we model the variability with Gaussian process (GP) covariance components including Matérn-3/2, damped-random-walk (DRW), stochastically driven damped simple-harmonic-oscillator (SHO), and white-noise terms. Bayesian model comparison reveals an X-ray stochastic-variability transition during the changing-look recovery phase. In the 2019 May 5 observation, the preferred covariance changes from a Matérn-3/2-like state to a DRW-like state within a single continuous exposure. A phenomenological gated-kernel estimate localizes this transition sharply in the hard band at $t_c\simeq23.5~{\rm ks}$, while the soft band shows the same qualitative change over a broader interval. This transition occurs after the X-ray corona had reappeared but before the later pronounced hardening and brightening of the coronal emission, suggesting an early timing-domain signature of disk–corona reconfiguration. Phenomenologically, the dominant variability evolves from a smoother, finite-memory correlated process to a rougher, shorter-memory red-noise process. In the later 2022–2024 observations, SHO-like components associated with the known millihertz QPO show increasing characteristic frequency and quality factor, indicating a faster and more coherent oscillatory component during the QPO-plus-jet phase. GP-based time-domain inference therefore provides a sensitive probe of stochastic-variability changes in recovering AGN coronae.
Read the full abstract

Instrumentation and Methods for Astrophysics

Exoplanetary Tour Design with Solar Sails: TheAntipodes Results in the GTOC13 Problem

Jack Yarndley, Adam Evans, Xingyu Zhou et al. (+2 more)

Solar sails present an attractive but challenging propulsion method for large-scale, long-duration trajectory design problems. In 2025, the 13th Global Trajectory Optimization Competition (GTOC13) presented a trajectory design problem involving an exoplanetary solar sailing spacecraft in the fictional Altaira system, where the goal is to collect scientific return from flybys of planets, comets, and asteroids. High-scoring solutions combine combinatorial gravity assist tour design with continuous solar sail trajectory optimization. This paper presents the solution approach developed by the team `TheAntipodes' during GTOC13. The approach combines several search and optimization stages: (1) trade studies to identify competitive entry opportunities, (2) large-scale beam search over ballistic gravity assist tours to identify beneficial planetary structures, (3) resonant targeting strategies for Vulcan flyby sequences, and (4) multi-leg solar sail trajectory refinement using sequential convex programming (SCP). A key component of the refinement process is the use of a lossless control-convex solar sail formulation, which allows for large portions of the trajectory, including all gravity assist geometry and flyby timing, to be optimized simultaneously to maximize score. The resulting trajectory placed third, with a score of 337.878 from 133 scoring flybys, and exhibited a structure broadly similar to those of the other high-scoring solutions. This demonstrates the scalability of methods such as SCP for very large trajectory design problems.
Read the full abstract

All authors Jack Yarndley, Adam Evans, Xingyu Zhou, Minduli Wijayatunga, Roberto Armellin

Instrumentation and Methods for Astrophysics

SAXO+, the second-stage adaptive optics for SPHERE: NCPA compensation and dark-hole loop with a pyramid wavefront sensor

Johan Mazoyer, Charles Goulas, Raphaël Galicher et al. (+21 more)

The SAXO+ upgrade of the VLT/SPHERE adaptive optics system introduces a second-stage near-infrared pyramid wavefront sensor to improve high-contrast imaging, making accurate calibration of non-common path aberrations (NCPAs) essential to fully exploit its performance. This work refines the expected level of NCPAs in SAXO+ and presents the calibration procedures developed for static NCPA compensation and focal-plane dark-hole control. Monte Carlo simulations based on an updated Zemax optical model were used to estimate the NCPA error budget. These simulations are in good agreement with previous measurements on SPHERE and with the assumptions adopted in earlier performance studies. We also propose a calibration strategy that offloads most static aberration correction to the first-stage deformable mirror while preserving the second-stage mirror stroke for high-speed adaptive optics correction. These results validate the expected SAXO+ optical quality and establish the calibration framework required for efficient NCPA compensation and focal-plane wavefront control during future on-sky operations.
Read the full abstract

All authors Johan Mazoyer, Charles Goulas, Raphaël Galicher, Axel Potier, Fabrice Vidal, Florian Ferreira, Arnaud Sevin, Clémentine Béchet, Isaac Bernardino Dinis, Anthony Boccaletti, Gael Chauvin, Fausto Cortecchia, Emiliano Diolaiti, Nicolas Galland, Caroline Kulcsár, Maud Langlois, Matteo Lombini, Julien Milli, Mamadou N'diaye, Henri-François Raynaud, Laura Schreiber, Michel Tallon, Arthur Vigan, François Wildi

Instrumentation and Methods for Astrophysics · Cross-listed from eess.SY

Analytical Confidence Boundaries for Non-Gaussian Uncertainty in Perturbed Spacecraft Dynamics

Niccolò Michelotti, Ethan R. Burnett and Francesco Topputo

This work investigates nonlinear uncertainty propagation in perturbed astrodynamics, focusing on the rapid characterization of non-Gaussian distributions and the construction of three-dimensional "banana-shaped" confidence boundaries. To bridge the gap between computationally intensive high-fidelity methods and inaccurate linear approximations, this paper introduces a fully analytical, sample-free framework for higher-order moments extraction. Leveraging Differential Algebra to bypass repeated numerical integration, statistical moments are extracted analytically via Isserlis' theorem and a monomial-to-Hermite basis transformation. A pair-product projection strategy is exploited to overcome the severe computational bottleneck of full fourth-order tensor contractions and compute only relevant terms via efficient polynomial algebra. The extracted skewness and kurtosis components directly parameterize non-elliptical confidence geometries that capture spatial bending and out-of-plane coupling of typical non-Gaussian distributions in astrodynamics. The approach is validated in high-fidelity environments including a cislunar Near-Rectilinear Halo Orbit and close-proximity trajectories around Apophis during Earth's flyby, where the analytical approach achieves geometric accuracy comparable to expensive Monte Carlo simulations while reducing computational runtime by orders of magnitude.
Read the full abstract

High Energy Astrophysical Phenomena

Intrinsic Spectral Curvature from Finite-Cycle Transport at Relativistic Shocks

Ji-Hoon Ha

Power-law spectra are a central prediction of shock acceleration and are commonly associated with asymptotic scale invariance under diffusive transport. In finite relativistic shocks, strong anisotropy and limited residence times may restrict the number of effective shock crossings before the many-cycle diffusive limit is established. This work develops a reduced finite-cycle framework in which particle energization is described by discrete shock-crossing mappings, while downstream transport is encoded through an energy-dependent return probability. In this formulation, the local spectrum is controlled by the competition between the mean energy gain per cycle and the probability of surviving to the next cycle. A systematic decrease of the return probability with energy then produces intrinsic spectral curvature as a consequence of transport-limited cycle survival. The energy dependence of the return probability is estimated from the competition between magnetic deflection, downstream advection, and finite shock lifetime, yielding a characteristic steepening scale determined by macroscopic source parameters. For fiducial parameters relevant to compact blazar emission regions, the steepening scale lies below the ultimate acceleration cutoff, so that curvature can appear before the terminal maximum energy is reached. These results point to a pre-asymptotic finite-cycle limit of relativistic shock transport in which non-power-law spectra can arise from the limited survival of repeated shock-crossing cycles.
Read the full abstract

Solar and Stellar Astrophysics

Electron Acceleration and Plasma Heating in an Impulsive Confined C-class Solar Flare

I.N. Sharykin, I.V. Zimovets, G.V. Koynash et al. (+3 more)

A detailed analysis of the impulsive C2.8 solar flare SOL2023-03-19T02:12 is presented, focusing on the microwave (MW) and X-ray domains. The flare was selected because of its impulsive nature, the relatively simple magnetic morphology of its parent active region (AR) NOAA 13256, its confined evolution, its moderate intensity, pronounced non-stationary temporal behaviour, and the availability of a unique multi-wavelength dataset. This dataset includes MW spectral observations in the frequency range 2.8-12 GHz obtained with the new Solar Radio Spectropolarimeter (SOLARSPEL), together with MW images from the Siberian Radioheliograph (SRH). The flare was also observed by two imaging X-ray telescopes, Solar Orbiter/STIX and ASO-S/HXI. Nonlinear force-free field extrapolations are used to reconstruct the three-dimensional magnetic configuration of the AR. We present evidence for a direct coupling between the thermal plasma and the non-thermal electron population in the frame of collisionless plasma during the initial flare stage. Some simple relationships about electron acceleration process are presented and discussed. Analysis of the extrapolated magnetic field indicates that the flare onset was associated with a system of low-lying sheared magnetic loops located along the polarity inversion line (PIL). Given the confined nature of the event and the reconstructed magnetic configuration, we infer that magnetic reconnection most likely occurred within current sheets possessing a substantial guide-field component. The observed non-stationary QPPs in the non-thermal emission, with periods decreasing from approximately 15 to 9 s, are interpreted as signatures of a sequence of magnetic reconnection episodes occurring in different magnetic structures and triggered quasi-periodically by a process that remains uncertain, but which may involve propagating slow magnetoacoustic waves.
Read the full abstract

All authors I.N. Sharykin, I.V. Zimovets, G.V. Koynash, E.F. Ivanov, V.V. Fedenev, S.A. Anfinogentov

High Energy Astrophysical Phenomena

A spectacular multi-wavelength transient associated with an off-axis relativistic jet

Delina Levine, Gregg Hallinan, Jean J. Somalwar et al. (+10 more)

Many of the most luminous extragalactic transients originate from the accretion of material onto a black hole (BH) via core-collapse, stellar mergers, or the tidal disruption of a star. Some produce energetic multi-wavelength emission, displaying short, blue optical flares and bright, long-lived radio afterglows. In rare cases, these have also launched powerful relativistic jets almost exclusively detected on-axis via high-energy emission. Here we report AT 2019ijn, a radio transient discovered in the Very Large Array Sky Survey, associated with a powerful relativistic jet viewed off-axis and accompanied by a luminous ($\nu L_{\nu, opt} \sim 10^{44}$ erg/s) optical transient. Originating from a star-forming dwarf galaxy at z = 0.273, AT 2019ijn's optical flare exhibited a fast rise ($t_{rise, rest} \sim 7$ d) and shallow decline ($t_{dec, rest} > 38$ d), followed a year later by an energetic ($E \sim 2\times10^{52}$ erg) radio counterpart persisting for $>6$ years. These combined properties are unprecedented and preclude known classes of stellar explosion powered by core-collapse. Instead, the implied accretion onto a BH and associated off-axis jet invokes an exotic BH-stellar merger or a jetted tidal disruption event (TDE) by a $10^4 - 10^6 M_\odot$ black hole. Favoring a TDE, this work determines the jet-launching occurrence, with the low redshift allowing constraints on the late-time evolution in contrast to prior events. Upcoming radio sky surveys will offer an unprecedented new window for further discovery of AT 2019ijn-like off-axis relativistic transients.
Read the full abstract

All authors Delina Levine, Gregg Hallinan, Jean J. Somalwar, Dillon Z. Dong, Ehud Nakar, Kenta Hotokezaka, Vikram Ravi, Assaf Horesh, Jessie M. Miller, Casey Law, Steven T. Myers, Stella K. Ocker, Daniel D. Kelson

Friday 10 July

Astrophysics of Galaxies · Cross-listed from physics.gen-ph

Determination of $H_{0}$ with a Photometric AGN Golden Sample derived from a joint SN Ia-QSO cosmological reconstruction

Sebastian Rueda-Blanco, Mario A. Higuera-G. and Camilo Delgado-Correal

The current tension between early and late-Universe determinations of the Hubble constant motivates the development of independent high-redshift distance tracers. Quasars, as luminous active galactic nuclei - AGNs, provide a promising route through the empirical relation between their X-ray and ultraviolet luminosities.We construct a joint Type Ia supernova-quasar Hubble diagram and investigate whether a statistically selected quasar subsample can define a preliminary golden sample for future AGN standardization. We combine calibrated Type Ia supernovae with SDSS DR14 quasars and infer the cosmological parameters from the posterior distribution of a joint model. Posterior medians and credible intervals are obtained from the marginalized distributions. We further define redshift-dependent quasar pools from SDSS queries and select the most representative sources in each bin using a multivariate statistical-distance criterion based on redshift, optical magnitudes, and SDSS colors. The posterior analysis yields $H_0 = 71.76^{+1.67}_{-1.31}\,\mathrm{km\,s^{-1}\,Mpc^{-1}}$ and $\Omega_m = 0.294^{+0.014}_{-0.012}$. The statistically selected quasar candidates reproduce the reference Hubble diagram with small residual dispersion across multiple redshift intervals and remain broadly distributed across the SDSS angular footprint without evidence of strong artificial clustering induced by the selection procedure.
Read the full abstract

Earth and Planetary Astrophysics · Cross-listed from physics.chem-ph

New Hydrolysis Rate Constants Reveal Longest Cyanide Persistence in Cool, Neutral Waters

Sai Shruthi Murali, Skyla B. White and Paul B. Rimmer

Hydrogen cyanide (HCN) is a key molecule in prebiotic chemistry, and its availability in water is limited by hydrolysis. In this work, we estimate the hydrolysis rates of \ce{HCN}, particularly the errors associated with the rates as a function of temperature, pH and in the presence of salts containing sulfite, sulfide and phosphate. For pure water, we find an acid-catalyzed hydrolysis rate constant at ${\rm 0 ^{\circ}C}$ of $\ln (k^+_{273}/1\,{\rm M^{-1} s^{-1}}) = -12.7 \pm 1.12$ with an activation energy of $67.1 \, {\rm kJ \, mol^{-1}}$. We find a base-catalyzed rate constant of $\ln (k_{273}^-/1\,{\rm M^{-1} s^{-1}}) = -9.0 \pm 1.27$ at ${\rm 0^{\circ}C}$ with an activation energy of $89.5 \, {\rm kJ \, mol^{-1}}$. These values are consistent with estimates from the literature within our uncertainties at ${\rm pH} > 8$ but diverge from literature values at lower pH. In the presence of salts, hydrolysis is accelerated under acidic conditions to 6–14$\times$ the acid-catalyzed rate without salts. However, at ${\rm pH \gtrsim 8}$ hydrolysis rates become $2.5\times$ times slower with sulfite and sulfide. These results demonstrate the importance of estimating uncertainties associated with rates when constraining the maximum concentrations of prebiotic molecules attainable in natural waters on the Earth and other planets.
Read the full abstract

Instrumentation and Methods for Astrophysics

Quantifying Foreground Contamination in the Dark Ages 21 cm Power Spectrum Using an Electromagnetically Simulated Dipole Antenna Atop a Dielectric Surface

Willow Smith, Jonathan C. Pober, Bang D. Nahn et al. (+2 more)

The highly-redshifted 21 cm signal from the cosmic Dark Ages presents an exciting frontier for cosmology, with the potential to observe a large number of Fourier modes of the cosmic density field in the absence of complicating astrophysical phenomena. Because the Earth's ionosphere and human-generated interference affect these low radio frequencies, the lunar far side - the most radio-quiet region in the inner solar system - is considered the ideal site to conduct such an experiment. The bright synchrotron foregrounds at these frequencies are expected to be spectrally smooth and thus occupy a subset of spectral Fourier modes, leaving an observable "window" to the Dark Ages signal. However, in practice, spectral structure arises in foregrounds due to instrumental artifacts, leading to a spillover of foreground power into the observable window. In this paper, we quantify this spillover for a set of simulated visibility measurements given a number of antenna beams, sky models, and baseline configurations. Notably, we examine the effects on foreground spillover due to variations in the lunar regoliths using two numerically simulated beam models with 1 and 4 layers of substrate materials underneath. We find that the regolith material properties can induce unwanted spectral structure in the beams, which potentially prevents foreground power suppression at the levels required. The detailed spectral behavior depends on the lunar regolith model used, making it paramount to produce both accurate models of foregrounds and of the lunar regolith for Dark Ages cosmology.
Read the full abstract

All authors Willow Smith, Jonathan C. Pober, Bang D. Nahn, Jack O. Burns, Ronald S. Polidan

Astrophysics of Galaxies

Challenges in probing turbulent and magnetic support in cores: the W43-MM1 protocluster case study

M. Valeille-Manet, F. Louvet, F. Motte et al. (+13 more)

Estimating the level of non-thermal support in cores is both challenging and crucial for constraining the earliest stages of star formation. We quantify the kinetic and magnetic support operating within the cores of the high-mass protocluster W43-MM1, and test the assumptions behind the virial theorem used to interpret observations. We used ALMA 12m molecular line observations of DCN (3-2), 13CS (5-4), and CH3CN (5_3-4_3) to estimate kinetic support. The plane-of-sky magnetic field strength (B_POS) was derived from dust-polarization observations using the Davis-Chandrasekhar-Fermi method, obtained at the three-beam scale (~12500 au) and extrapolated to core scales (~2500 au) using the density-field strength relation. We derive kinetic support estimates for 45 cores (21 prestellar and 24 protostellar), of which 21 also have magnetic field estimates. Velocity dispersions range from 0.34 to 4.48 km/s, and B_POS values span 1.1-49.3 mG at core scales. Using the virial theorem, ~70% of cores appear stable against collapse when considering turbulence alone, and ~85% when combining both kinetic and magnetic support (alpha_vir,B > 1). These are unexpectedly high values, particularly for protostellar cores expected to be undergoing collapse. We conclude that contamination of linewidths by organized motions (1-3 km/s, consistent with previous observational studies), together with the omission of surface terms in the observational virial theorem, prevents accurate measurement of non-thermal support in cores. This highlights that simplified virial analyses can introduce significant biases when assessing physical support mechanisms within cores.
Read the full abstract

All authors M. Valeille-Manet, F. Louvet, F. Motte, A. M. Stutz, C. Arce-Tord, P. C. Cortés, M. Fernandez-Lopez, N. A. Sandoval-Garrido, P. Sanhueza, R. H. Álvarez-Gutiérrez, S. Chevalier, A. Ginsburg, A. Koley, P. Saha, S. Savorgnano, R. Veyry

Earth and Planetary Astrophysics

Solar Wind Proton Implantation and Hydrogen Diffusion: Model Comparisons to M3 Observations

O. J. Tucker, W. M. Farrell, S. Li et al. (+3 more)

The Moon Mineralogy Mapper (M3) observed a widespread 3-micron absorption feature on the lunar surface, commonly attributed to surficial OH and/or H2O. The feature varies with latitude, local time, and lunar phase, suggesting that at least part of the optically active reservoir is dynamic. We compare phase- and local-time-resolved M3 abundance estimates with a global solar wind proton implantation, hydrogen diffusion, and H2 exosphere model. The model tracks implanted H in the upper grain rim, thermally activated retention and loss, recombinative H2 release, and phase-driven source variations associated with the solar wind, magnetosheath, and magnetotail. We compute the surface abundance using a weighted activation-energy-bin representation, in which the activation-energy distribution is discretized into fixed probability-weighted bins rather than sampled stochastically by Monte Carlo particles. This implementation reduces particle sampling noise in low-flux regions. A refined grid of Gaussian effective activation-energy distributions shows that the low- and mid-latitude M3 trends are best matched by distributions centered near Ec = 0.520 eV with width Ew = 0.090 eV. The preferred case gives a combined low- and mid-latitude RMSE of approximately 27 ppm and a small mean bias of only a few ppm. These fitted parameters should be interpreted as an effective response of the M3-sensitive retained H/OH reservoir, not as a unique mineralogical activation energy. The model reproduces the dominant local-time and phase-dependent abundance structure, including the reduced retained abundance near local noon, while model-data differences near plasma-transition intervals and high-latitude behavior may reflect additional sampling, saturation, or surface-plasma processes.
Read the full abstract

All authors O. J. Tucker, W. M. Farrell, S. Li, A. R. Poppe, Kennedy White, Valeriy Tenishev

Solar and Stellar Astrophysics

LISA's view of the Galactic Halo: forecasts for the Galactic double white dwarf population using Gaia data

Ann-Marsha Alexis and Katelyn Breivik

The population of close double white dwarfs (DWDs) in the Milky Way will make up the largest population of sources resolved by LISA, with a subset of the population having three-dimensional position and chirp mass measurements obtained from LISA observations. Because white dwarfs are the bulk of the Milky Way's stellar remnant population, the positions and masses of close DWDs resolved by LISA are defined by the stellar population properties that host them. Recent Gaia data has unveiled a triaxial accreted component of the Galactic stellar halo: the Gaia-Sausage-Enceladus, which contains stars that are more metal-rich than the extremely metal-poor population of stars residing in the stellar halo beyond 30 kpc. In this work, we assess the size and characteristics of the population of close DWDs using an empirically motivated Galactic model which incorporates the GSE and compare to the classical Galactic model that contains only a single very metal-poor halo population. To do this, we simulate a realistic present-day Galactic DWD population and determine its gravitational wave signal in LISA using LEGWORK. We find that incorporating the metal-rich population from the GSE imprints significant differences in the chirp mass and distance distributions of resolved DWDs, but that the strength and height of the gravitational wave foreground remains unchanged.
Read the full abstract

Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Suppressing Extra-Dimensional Axion Isocurvature Dynamically

Gongjun Choi and Tony Gherghetta

Extra-dimensional QCD axion is well motivated by string compactifications and enjoys enhanced protection against quality-violating effects. If present during inflation, however, its quantum fluctuations generate isocurvature perturbations that strongly constrain the inflationary scale. We propose a dynamical suppression mechanism in warped five-dimensional models, where a radion-inflaton coupling sets the radion minimum at small inter-brane separation during inflation, temporarily enhancing the effective four-dimensional axion decay constant. After inflation, the radion minimum shifts to larger separation, restoring the standard QCD axion window. In a warped orbifold GUT with Goldberger-Wise stabilization, this mechanism can satisfy CMB isocurvature bounds while allowing substantially higher inflationary scales than in conventional pre-inflationary axion cosmology.
Read the full abstract

Solar and Stellar Astrophysics

Intrinsic iron abundance spreads in globular clusters

J. Schiappacasse-Ulloa, S. Lucatello, L. Magrini et al. (+2 more)

Globular Clusters (GCs) host multiple stellar populations, likely composed of a subset of FG stars that enriched the intracluster medium and gave rise to SG stars, each characterised by distinctive chemical patterns. These patterns typically include enhancements in elements such as N, Na, and Al, coupled with depletions in C, O, and Mg in SG stars. Traditionally, heavier elements such as those in the Fe-peak were considered unaffected in most GCs. However, recent studies have reported significant internal spreads in these elements, suggesting a more complex picture of chemical enrichment within GCs. This study seeks to derive precise and homogeneous differential iron abundances in a large sample of GCs. By doing so, our aim is to investigate the presence of intrinsic iron spreads within them and to assess the existence of differences in Fe between their stellar populations. We used the Python-based tool Q2 to determine both differential stellar parameters and iron abundances for 92 sibling stars, defined by the similarities in their stellar parameters, across 13 Galactic GCs. This differential approach reduces the influence of non-LTE effects, and minimises observational errors, and systematic biases linked to stellar parameters. We performed Monte Carlo simulations to evaluate the statistical significance of the measured spreads. Most of the GCs in our sample do not show evidence of statistically significant Fe spreads. Only a few exceptions emerge, namely NGC1851, NGC3201, and NGC5634, which display a highly significant iron spread. In particular, NGC3201 shows a particularly pronounced spread in its FG population, reflecting a potential inhomogeneous iron abundance in its pristine material. Finally, through statistical tests, we conclude that our data do not support the presence of a widespread iron variation in GCs.
Read the full abstract

All authors J. Schiappacasse-Ulloa, S. Lucatello, L. Magrini, A. Bragaglia, E. Carretta

Astrophysics of Galaxies

Faraday depth similarities across scales with LoTSS & DRAGONS

Anna Ordog, Rebecca A. Booth, Ana Erceg et al. (+5 more)

Faraday rotation of diffuse Galactic synchrotron emission is a powerful tracer of the complex, magnetised interstellar medium (ISM), whose structures span a wide range of spatial scales, requiring both interferometric and single-antenna broadband radio polarisation observations for full characterisation. We compare Faraday rotation in the interferometric LOw-Frequency ARray Two-Metre Sky Survey (LoTSS; 120-168 MHz) and the single-antenna Dominion Radio Astrophysical Observatory Global Magneto-Ionic Medium Survey of the Northern Sky (DRAGONS; 350-1030 MHz), which are complementary in their sensitivity to spatial and Faraday-depth scales. We calculate first moments (M1) of polarised intensity versus Faraday depth, producing polarised-intensity-weighted mean Faraday depth maps of the regions common to both surveys. These maps show remarkable agreement between the surveys despite the lack of overlap in frequency or spatial-scale coverage. In the northern Galactic region, the M1 maps are morphologically similar with only small spatial shifts in the boundaries between positive and negative M1, and strong pixel-by-pixel correlation. In the southern Galactic region, both surveys trace the Faraday-depth gradient with Galactic longitude previously identified in LoTSS. Faraday depth spectra show consistent numbers and locations of peaks for more than half of the pixels. The strong structural similarity between the surveys, demonstrated by computing structure functions, suggests coupling across spatial scales in the magnetised ISM, enabling both interferometric and single-antenna observations to trace the same features. Instances of differences point to ISM configurations where observational effects such as depolarisation dominate or where this coupling breaks down due to local physical conditions.
Read the full abstract

All authors Anna Ordog, Rebecca A. Booth, Ana Erceg, Vibor Jelić, Jo-Anne C. Brown, Marijke Haverkorn, Alex S. Hill, T.L. Landecker

Astrophysics of Galaxies

Predicting ionised gas emission in 3D with SKIRT. I. Framework and validation

Anand Utsav Kapoor, Maarten Baes, Aaron Smith et al. (+7 more)

Emission lines from ionised gas are key diagnostics of star formation, metallicity, and ionisation conditions in galaxies. Interpreting spatially resolved observations from integral-field surveys (e.g. MaNGA, MUSE, JWST/NIRSpec) and comparing them with hydrodynamical simulations requires 3D photoionisation models that handle realistic geometries, dust attenuation, and synthetic instrument output. We present a new photoionisation module for the Monte Carlo radiative transfer code SKIRT that predicts emission-line luminosities of ionised gas in 3D, combining pre-computed Cloudy tables for gas temperature and opacity with a direct calculation of ion fractions and line emissivities. The local ionising radiation field (1-6 Ryd) is characterised by log U and four spectral-shape ratios; Cloudy tables map these to temperature and opacity, converging through SKIRT's existing iteration cycle. An inline solver then determines ion fractions from the converged field and temperature and evaluates line emissivities. We validate against Cloudy on 60 spherical shell models and against COLT on a Milky Way-analogue galaxy. On the 1D grid, hydrogen recombination lines agree with Cloudy to within a few per cent (Halpha median ratio 0.97) and the forbidden lines to within ~5%, except [S II] 6717 (1.23), whose offset traces a temperature overestimate near the ionisation front. In 3D, integrated luminosities agree with COLT to within 18% for the hydrogen lines and 2% for [N II], while [O III] and [S II] are elevated by ~70 and ~80%. Pixel-by-pixel correlation coefficients reach r >= 0.92, with luminosity-weighted scatter of 0.14-0.31 dex and broadly consistent BPT ratios. The module enables self-consistent synthetic observations in which ionised-gas emission lines, dust attenuation, and dust re-emission are computed in a single MCRT run, applicable to any hydrodynamical simulation.
Read the full abstract

All authors Anand Utsav Kapoor, Maarten Baes, Aaron Smith, Arno Lauwers, Andrea Gebek, Peter Camps, Sven De Rijcke, Arjen van der Wel, Kosei Matsumoto, William McClymont

High Energy Astrophysical Phenomena

A new likely pulsar binary in 47~Tucanae from continuum searches

Thomas J. Maccarone, Alessandro Paduano, Arash Bahramian et al. (+6 more)

We present evidence that the X-ray source 47~Tuc~W41, long considered to be an X-ray source powered by coronal activity, is actually a redback pulsar binary. The source continually shows $L_X = 3 \times 10^{31}$ erg s$^{-1}$ (0.5–10 keV), which is well in excess of the coronal saturation limit for active binaries in quiescence, but is consistent with the intrabinary shock observed in redback pulsars, as is its photon index of $\Gamma = 1.4\pm0.1$. In addition, using deep data from the Australia Telescope Compact Array, we show that W41 is a faint ($9.8\pm1.4 \mu$Jy at 5.5 GHz) steep spectrum ($\alpha = -1.8\pm0.4$) radio continuum source, as expected for a pulsar. Light curve modelling of Hubble Space Telescope photometry shows evidence for ellipsoidal modulation with mild irradiation of a $\sim 0.5$–$0.55 M_{\odot}$ secondary around an invisible companion, also consistent with the redback interpretation. The precise position of W41, along with its well-measured 10.4-hr orbital period, should enable it to be matched to a newly-discovered radio pulsar in future data. Our result shows that close pulsar binaries are still hiding, misclassified among active binaries, even in well-studied clusters like 47 Tuc.
Read the full abstract

All authors Thomas J. Maccarone, Alessandro Paduano, Arash Bahramian, Liliana Rivera Sandoval, Jay Strader, James C.A. Miller-Jones, Angiraben D. Mahida, Craig O. Heinke, Laura Chomiuk

Cosmology and Nongalactic Astrophysics

Assessing the large-scale angular clustering of UNIONS Lyman Break Galaxies via cross-correlations

Constantin Payerne, Christophe Yèche, William d'Assignies Doumerg et al. (+8 more)

Lyman-break galaxies (LBGs), selected via the strong spectral break blueward of the Lyman limit, are powerful tracers of large-scale structure at redshifts $z>2$. In this work, we assess the feasibility of using LBGs selected from the Ultraviolet Near Infrared Optical Northern Survey (UNIONS) multi-band photometric catalog as cosmological probes of the high-redshift Universe using two-point statistics. We demonstrate that spatially varying imaging systematics, driven by variations in PSF depth, seeing across the UNIONS footprint, limit robust measurements of the LBG auto-angular power spectrum on large scales, even after correcting the LBG field with linear or non-linear mitigation techniques. This study shows that clustering analyses of faint galaxy samples close to survey depth are challenging. We therefore turn to cross-correlation measurements with external tracers, in particular the Planck CMB lensing convergence and quasars from DESI DR1 and Quaia, which are less sensitive to the angular imaging systematics. Using both data and mock catalogues, we demonstrate that the LBG–CMB lensing cross-power spectrum can be measured more robustly than the auto-spectrum, with an amplitude consistent with theoretical predictions. Residual systematics primarily manifest as excess variance at large angular scales, without introducing a significant bias in the recovered signal. Taken together, these results establish UNIONS-selected LBGs as reliable tracers for cross-correlation cosmology at $z\sim 2.5$, and highlight cross-correlation techniques as a powerful and robust avenue for extracting cosmological information from photometric high-redshift galaxy samples in the presence of complex imaging systematics.
Read the full abstract

All authors Constantin Payerne, Christophe Yèche, William d'Assignies Doumerg, Hendrik Hildebrandt, Martin Kilbinger, Calum Murray, Thomas de Boer, Kenneth C. Chambers, Scott Chapman, Michael J. Hudson, Alan W. McConnachie

Astrophysics of Galaxies

SuperMIGHTEE : Spectral Ages of Remnant Radio Galaxy Candidates in the XMM-LSS Field

Sushant Dutta, Veeresh Singh, C.H. Ishwara Chandra et al. (+8 more)

Remnant radio galaxies, whose lobes are no longer replenished by jets from the active galactic nucleus (AGN), offer key constraints on AGN duty cycles and the timescales of radio jets. We present a spectral-ageing study of 14 candidate remnant radio galaxies in the XMM-LSS field, combining new broad-band data from the MeerKAT MIGHTEE (L-band) and uGMRT superMIGHTEE (band-3 and band-4) surveys with complementary observations from LOFAR, GMRT, and JVLA, covering 144 MHz-1.5 GHz. Spectral modeling confirms 12 sources as genuine remnants, while two are reclassified as active, emphasising the importance of sensitive, multi-frequency coverage for robust remnant identification. Pixel-based spectral age maps yield results (~3-43 Myr) broadly consistent with integrated estimates, revealing relatively short spectral ages (~8-42 Myr). These ages likely reflect enhanced inverse-Compton losses at higher redshifts (0.35 < z < 2.85; median z = 1.25) and possible rapid lobe expansion in low-density environments. The ratios of remnant to total source ages (t_OFF}/t_s) span 0.04-0.83, indicating that the sample traces a broad range of evolutionary stages. Our findings reveal a previously underrepresented population of faint, rapidly fading remnants, suggesting that the remnant phase may be shorter and more dynamic than previously thought. This study highlights the crucial role of MIGHTEE and superMIGHTEE surveys in reliably classifying genuine remnants and provides a framework for constraining AGN life cycles in preparation for forthcoming SKA surveys.
Read the full abstract

All authors Sushant Dutta, Veeresh Singh, C.H. Ishwara Chandra, Yogesh Wadadekar, Russ Taylor, Mattia Vaccari, Lucia Marchetti, Matt Jarvis, Catherine Hale, Solohery Randriamampandry, Zara Randriamanakoto

Cosmology and Nongalactic Astrophysics

Do Primordial Black Hole Clusters Survive the Galaxy? Collisional Disruption and Microlensing Implications

M.V. Tkachev and S.V. Pilipenko

We study the collisional disruption of primordial black hole (PBH) clusters in the Milky Way halo. Encounters between clusters strip PBHs into a diffuse component, and the fraction of PBH mass in this smooth component along a sightline determines how microlensing constraints divide between isolated compact objects and extended cluster lenses. We combine an analytic NFW-based collision-rate model, $72$ direct N-body binary collision simulations that calibrate the escaped-mass fraction as a universal function $\tilde f(\tilde v,\tilde b)$ of the relative velocity and impact parameter in units of the cluster velocity scale and half-mass radius, and cosmological N-body simulations of a Milky Way-like halo ($M_{200}\simeq 8\times10^{11}\,M_\odot$, $c_{200}\simeq 11$) that record the encounter history of every cluster from $z=9$ to $z=0$. For $10^6$ and $10^7\,M_\odot$ clusters – bracketing the maximum mass in the Carr et al.\ formation scenario – the local encounter rate at the Solar circle is $2.9\times10^{-3}$ and $1.2\times10^{-2}\,\rm Myr^{-1}$, consistent with the simulations to within ${\sim}40\%$. Because the peak-disruption velocity of Carr-radius clusters ($12$–$20\,\rm km\,s^{-1}$) lies far below typical halo encounter velocities, disruption accumulates through many weak encounters, most effectively during the early, cold phases of halo assembly: half of the total mass loss is inflicted before $z\approx2$, a channel that $z=0$ analytic estimates miss entirely. The surviving mass fraction at the Solar circle is $S\simeq0.50$ ($10^6\,M_\odot$) and $0.04$ ($10^7\,M_\odot$), and the DM-mass-weighted smooth fraction toward the LMC and SMC is $0.49$ and $0.92$, respectively. Cluster-cluster disruption is thus substantial over the Galaxy's lifetime, and reanalyses of microlensing surveys must account for the radially varying smooth fraction $f_{\rm sm}(r)$ derived here.
Read the full abstract

Earth and Planetary Astrophysics

How Many Transiting Giant Planets Can JWST Search for Moons and Rotational Oblateness?

Le-Chris Wang and Joshua N. Winn

Observations with the James Webb Space Telescope (JWST) can, in principle, detect moons and rotational oblateness of giant exoplanets through subtle distortions of transit light curves. The most favorable planets are expected to be on wide orbits ($\gtrsim$0.3~AU) where moons and rapid rotation are more likely to survive tidal evolution. No unambiguous detections have yet been reported. Here, we forecast the number of systems with sufficiently favorable properties to allow for secure detections, using JWST noise models, analytic detectability scalings, giant-planet occurrence rates, and the Gaia star catalog. For planets orbiting 0.9–1.6$\,M_\odot$ stars and a noise model based on demonstrated JWST performance, single-transit observations should be capable of detecting Jupiter-like rotational oblateness in several known systems and of order 10 systems yet to be discovered, if obliquities are typically $\gtrsim$10$^\circ$. A similar number of systems are favorable for Ganymede-sized moons, if such moons are common. The yields can increase to tens or hundreds of systems if lower-mass host stars are included or if JWST can achieve photon-limited performance. Time-correlated noise on 1–10 hr timescales can strongly suppress these yields; a noise floor of a few tens of parts per million is enough to hide oblateness or moons in many otherwise favorable systems. Successful searches will therefore require both a more complete census of long-period transiting giant planets and low levels of instrumental systematics and stellar variability.
Read the full abstract

High Energy Astrophysical Phenomena

The Radio Properties of Extreme Coronal Line Emitters: Constraints on the Sub-parsec Environment

Noah Franz, Kate D. Alexander, Collin T. Christy et al. (+10 more)

A tiny fraction ($\ll1\%$) of galaxies display luminous, high-ionization metal emission lines, which may be persistent or variable. These extreme coronal lines (ECLs) are produced when soft X-ray photons intercept dense gas ($n\gtrsim10^{6-7}~{\rm cm^{-3}}$). The high X-ray flux required implicates intense nuclear activity, likely originating from tidal disruption events (TDEs) and active galactic nuclei (AGN). As ECLs are rarely seen even within these classes, their production may also require specific environmental conditions, but the details remain unclear (e.g., the geometry and volume filling factor of the ECL-producing gas). Here, we present the radio properties of a population of $27$ low-redshift ($z<0.3$) ECL emitting galaxies (ECLEs), providing a unique and previously unexplored probe of the properties of the circumnuclear medium (CNM; $\lesssim1$ pc from the black hole) in these systems. We find that $\sim 50\%$ of ECLEs produce radio synchrotron emission with luminosity and evolution consistent with TDEs and/or AGN. Radio spectral modeling of four ECLEs reveals that the ECL-producing region is (1) clumpy with a low volume filling factor ($10^{-5}\lesssim f_{V}\lesssim10^{-2}$) and (2) likely distinct from the radio emitting region (implying, e.g., a clumpy toroidal geometry). For time-variable ECLEs, these are some of the first observational constraints on the CNM geometry in formerly quiescent galactic nuclei. The unique nature of ECLEs makes them an excellent high-energy laboratory to connect the physics of accretion, photoionization, and feedback in galactic nuclei, thus motivating continued multi-wavelength monitoring.
Read the full abstract

All authors Noah Franz, Kate D. Alexander, Collin T. Christy, Tanmoy Laskar, Stefanie Komossa, Enrico Ramirez-Ruiz, Jean Somalwar, Edo Berger, Ryan Chornock, Fabio De Colle, Gavin Farley, Megan Newsome, B. Ashley VanderLey

Instrumentation and Methods for Astrophysics

LISA 10 – Library and Information Services in Astronomy. Report on the ESO workshop

Leslie Kiefer, Uta Grothkopf, Silvia Meakins et al. (+1 more)

The 10th LISA conference (LISA 10) took place at ESO Chile in early November 2025. The theme, Research Equity and Access in the Age of AI, highlighted the rapidly evolving landscape of scholarly communication in astronomy. Artificial intelligence, open access mandates, and expanding data archives are transforming scientific practice and information in an increasingly interdisciplinary research environment. Through presentations, posters, and discussions, LISA 10 explored how these developments are redefining the management of astronomy information work and the role of librarians.
Read the full abstract

All authors Leslie Kiefer, Uta Grothkopf, Silvia Meakins, Mahmut Eren