Astrophysics of Galaxies
A dust condensation instability in AGN atmospheres: failed winds and the broad line region
James E. Owen and Douglas N. C. Lin
Active
galactic nuclei (AGN) are important drivers of
galactic evolution; however, the underlying physical processes governing their properties remain uncertain. In particular, the specific cause for the generation of the broad-line region is unclear. There is a region where the underlying
accretion disc atmosphere becomes cool enough for
dust condensation. Using models of the disc's vertical structure, accounting for
dust condensation and irradiation from the central source, we show that their upper atmospheres become extended, dusty, and radiation-pressure-supported. Due to the density–temperature dependence of
dust condensation, this extended atmosphere forms as the
dust abundance slowly increases with height, resulting in density and temperature scale heights considerably larger than the gas pressure scale height. We show that such an atmospheric structure is linearly unstable. An increase in the gas density raises the
dust sublimation temperature, leading to an increased
dust abundance, a higher opacity, and hence a net vertical acceleration. Using localised 2D hydrodynamic simulations, we demonstrate the existence of our linear instability. In the non-linear state, the disc atmosphere evolves into “fountains” of dusty material that are vertically launched by radiation pressure before being exposed to radiation from the central source, which sublimates the
dust and shuts off the radiative acceleration. These
dust-free clumps then evolve ballistically, continuing upward before falling back towards the disc under
gravity. This clumpy ionized region has velocity dispersions $\gtrsim 1000$ km/s. This instability and our simulations are representative of the Failed Radiatively Accelerated Dusty
Outflow (FRADO) model proposed for the AGN broad-line region.
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Instrumentation and Methods for Astrophysics
Unveiling the Cosmos: XMM-Newton's Scientific Strategy
Norbert Schartel and Maria Santos-Lleo
In December 2024, the European Space Agency's (ESA) XMM-Newton X-ray Observatory celebrated the 25th anniversary of its launch. The annual number of peer-reviewed articles utilising XMM-Newton data has exhibited a consistent upward trajectory over the past two and a half decades, attaining more than 400 in 2022. The annual call for observing time proposals continues to experience a high level of oversubscription, typically ranging from a factor of 6 to 7. In order to enhance the scientific discovery space, XMM-Newton, primarily through the Project Scientist and Science Operations Centre, has pursued a strategy of expansion, which can be grouped into three phases: Large Projects with long observing time (2006-2009), Joint Observations (2011-2016), and Targets of Opportunity (2016-2024), respectively. A salient feature of XMM-Newton's time allocation is the systematic removal of biases from the second call onwards, a strategy that has enabled the attainment of comparable gender success rates and high acceptance rates for young scientists over 25 years, a feat only recently accomplished by similar missions through the introduction of double-anonymous review. XMM-Newton research is conducted by an active community of 4,300 scientists, of which approximately 570 are leading (1st author). The foundation of this community and its research is predicated on XMM-Newton data, with the project's policy of user support and calibration being fundamental constituents, as well as the project's active engagement and communication with its members.
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High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Accuracy of ringdown models calibrated to numerical relativity simulations
Francesco Crescimbeni, Gregorio Carullo, Emanuele Berti et al. (+3 more)
The ”ringdown” stage of gravitational-wave signals from binary black hole mergers, mainly consisting of a superposition of quasinormal modes emitted by the merger remnant, is a key tool to test fundamental physics and to probe black hole dynamics. However, ringdown models are known to be accurate only in the late-time, stationary regime. A key open problem in the field is to understand if these models are robust when extrapolated to earlier times, and if they can faithfully recover a larger portion of the signal. We address this question through a systematic time-domain calculation of the mismatch between non-precessing, quasi-circular ringdown models parameterised by the progenitor binary's degrees of freedom and full numerical relativity inspiral-merger-ringdown waveforms from the Simulating eXtreme Spacetimes (SXS) simulation catalog. For the best-performing models, the mismatch is typically in the range $[10^{-6}, 10^{-4}]$ for the $(\ell,|m|)= (2,2)$ harmonic, and $[10^{-4}, 10^{-2}]$ for higher-order modes. Our findings inform ongoing observational searches for quasinormal modes, and underscore the need for improved modeling of higher-order modes to meet the sensitivity requirements of future gravitational-wave detectors.
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All authors Francesco Crescimbeni, Gregorio Carullo, Emanuele Berti, Giada Caneva Santoro, Mark Ho-Yeuk Cheung, Paolo Pani
Solar and Stellar Astrophysics
Distributions and evolution of the equatorial rotation velocities of 2937 BAF-type main-sequence stars from asteroseismology
Conny Aerts
Studies of the rotational velocities of intermediate-mass main-sequence
stars are crucial for testing
stellar evolution theory. They often rely on spectroscopic measurements of the projected rotation velocities. These not only suffer from the unknown projection factor but tend to ignore additional line-profile broadening mechanisms aside from rotation, such as pulsations and turbulent motions near the
stellar surface. This limits the accuracy of Veq distributions. We use asteroseismic measurements to investigate the distribution of the equatorial rotation velocity, its ratio with respect to the critical rotation velocity, and the specific angular momentum for several thousands of BAF-type
stars, covering a mass range from 1.3M$_\odot$ to 8.8M$_\odot$ and almost the entire core-hydrogen burning phase. We rely on high-precision model-independent internal rotation frequencies, as well as on masses and radii from asteroseismology to deduce Veq, Veq/Vcrit, and J/M for 2937
gravity-mode pulsators in the Milky Way. The sample
stars have rotation frequencies between almost zero and 33$\mu$Hz, corresponding to rotation periods above 0.35d. We find that intermediate-mass
stars experience a break in their J/M occurring in the mass interval $[2.3,2.7]\,$M$_\odot$. We establish unimodal Veq and Veq/Vcrit distributions for the mass range $[1.3,2.5[$M$_\odot$, while
stars with $M\in[2.5,8.8]$M$_\odot$ reveal some structure in their distributions. We find that the near-core rotation slows down as
stars evolve, pointing to very efficient angular momentum transport. The kernel density
estimators of the asteroseismic internal rotation frequency, equatorial rotation velocity, and specific angular momentum of this large sample of intermediate-mass field
stars can conveniently be used for population synthesis studies and to fine-tune the theory of
stellar rotation across the main sequence
evolution.
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Astrophysics of Galaxies
The Challenge in Illuminating the Invisible: Constraining LyC Escape with Bayesian Modelling and Symbolic Regression
Amanda Stoffers, Sandro Tacchella, Charlotte Simmonds et al. (+2 more)
Direct observations of Lyman continuum (LyC) radiation from
galaxies during the Epoch of Reionization (EoR) are impeded by absorption in the intergalactic medium, requiring indirect methods to infer the escape fraction of ionizing
photons ($f_{\rm esc}^{\rm LyC}$). One approach is to develop and validate such methods on local analogues of the high-
redshift galaxies with directly detected LyC leakage. In this study, we constrain $f_{\rm esc}^{\rm LyC}$ using a
Bayesian spectral energy distribution (SED) fitting framework built on Prospector, which incorporates a non-parametric
star-formation history, a flexible
dust attenuation curve, self-consistent nebular emission, and fiber aperture-loss corrections. Our methodology jointly fits broadband photometry and emission line fluxes. We apply six models to the Low-
redshift LyC Survey (LzLCS), a sample of local
galaxies with physical properties comparable to EoR
galaxies, and evaluate them based on their ability to recover the observed flux and their relative
Bayesian evidence. The best-performing model is further assessed through a parameter recovery test, demonstrating that $f_{\rm esc}^{\rm LyC}$ can be recovered within uncertainties. Building on these results, we present updated $f_{\rm esc}^{\rm LyC}$ estimates for the LzLCS sample, with a median of 4%, and values reaching as high as 51%, with 26 of 64
galaxies having a cosmologically relevant $f_{\rm esc}^{\rm LyC}$($\gtrsim5\%$). Additionally, we present a revised UV $\beta$-slope vs $\log_{10}(f_{\rm esc}^{\rm LyC})$ relation, derived using symbolic regression with PySR trained on a synthetic
dataset generated with Prospector:$\log_{10}(f_{\rm esc}^{\rm LyC}) = (-2.30 \pm 1.28)\beta - (6.26 \pm 2.91)$, ($\sigma = 0.43$~dex). The relation successfully reproduces the $f_{\rm esc}^{\rm LyC}$ obtained from full SED fitting of the LzLCS sample within $1\sigma$.
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All authors Amanda Stoffers, Sandro Tacchella, Charlotte Simmonds, Benjamin D. Johnson, Roberto Maiolino
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Dark Secrets of Baryons: Illuminating Dark Matter-Baryon Interactions with JWST
Souradeep Das, Ranjini Mondol, Abhijeet Singh et al. (+1 more)
The James Webb Space
Telescope (JWST) has discovered bright
galaxies at high
redshifts ($z\approx 10-14$) and various
galaxy candidates extending to even higher
redshifts ($z\approx 15-30$). Many astrophysical and beyond the Standard Model physics scenarios have been proposed to explain these observations. We investigate, for the first time, the implications of dark matter (DM) scattering with
baryons (
protons and electrons) in light of the JWST UV luminosity function (UVLF) observations. These interactions suppress structure formation on
galactic scales, which may have an observable effect on the UVLF measurements at high
redshifts. Using a recent
galaxy formation model designed to explain high
redshift observations, we obtain strong upper limits on DM-
baryon scattering cross-sections and explore new regions of the parameter space. For DM-
proton scattering with cross-section $\propto v^{-2}$ velocity dependence, we obtain the strongest limit for DM masses of $\sim$ 1 – 500 MeV. For other cases that we study (DM-
proton scattering cross-section $\propto v^{0},\,v^{-4}$ and DM-electron scattering cross-section $\propto v^{0},\,v^{-2},\,v^{-4}$, our limits are competitive with those obtained from other cosmological observables. Our study highlights the potential of JWST observations as a novel and powerful probe of non-gravitational interactions of DM.
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All authors Souradeep Das, Ranjini Mondol, Abhijeet Singh, Ranjan Laha
Astrophysics of Galaxies
Mark Dodici, Scott Tremaine and Yanqin Wu
Stellar binaries in
galactic centers are relevant to several observable phenomena, including hypervelocity
stars, X-ray binaries, and mergers of
stars and compact objects; however, we know little about the properties of these binaries. Past works have suggested that a small fraction of them should contract to a few
stellar radii or collide, due to the co-operation of
stellar tides and the eccentricity oscillations induced by the strong
tidal field of the central massive black hole. We revisit this model with several updates. We first argue that when a binary's pericenter separation is driven down to a few
stellar radii, diffusive excitation of
stellar tides should quickly contract the orbit, saving the
stars from collision. Instead, the
stars should end up as a very tight binary. We then show that vector resonant relaxation and perturbations from passing
stars – effects not included in past models – dramatically increase the prevalence of such encounters. In numerical experiments, we find that 1 in 5 binaries around 1 pc from Sgr A* should tidally contract in this way while still on the main sequence. This rate climbs to 3 in 5 around 0.01 pc, inward of which it plateaus. We briefly discuss observable implications of these results, with particular
attention to young
stellar binaries in the
Galactic Center.
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Astrophysics of Galaxies
A close look at the black hole masses and hot dusty toruses of the first quasars with MIRI-MRS
Sarah E. I. Bosman, Javier Álvarez-Márquez, Frederick B. Davies et al. (+29 more)
The presence of supermassive black holes (SMBHs, $M_\text{BH}\sim10^9 M_\odot$) at $z>7$ remains a puzzle. While their existence appears to require exotic formation or growth processes, it is possible that BH mass estimates are incorrect due to differences from the low-$z$
quasars where BH mass scaling relations are calibrated. In this work, we employ JWST MIRI-MRS spectroscopy to measure the rest-frame optical/IR properties of the four highest-
redshift known luminous type-1
quasars at $7.08\leq z<7.64$. We use three new broad lines to measure updated BH masses, H$\alpha$, Pa$\alpha$ and Pa$\beta$, finding them to be in the range $(4-15)\cdot10^8 M_\odot$. Our black hole mass estimates from all tracers agree with each other and with previous, less accurate, ground-based measurements based on MgII. The flux ratios of the H lines deviate from expectations for case A and B recombination in the same way as in $z<3$
quasars, indicating similar physical conditions in the Broad Line Region. Rest-frame near-IR continuum emission from a hot dusty
torus surrounding the
accretion disc is unambiguously detected in all four objects. We model the emission with SKIRTOR and constrain the inclination (face-on) and the opening angle ($\theta=40-60^\circ$) of the
tori. These constraints are consistent for the four objects and with expectations from luminous
quasars. We estimate a total
dust mass $(1-4)\cdot10^6 M_\odot$ in the
tori, corresponding to $(0.2-7)\%$ of the total
dust in the
quasar host
galaxies. Given observed
accretion rates, these SMBHs will deplete their
tori in only $\sim5$ Myr. Overall, we confirm that $z>7$ SMBHs in
quasars could not have grown from
stellar-remnant BHs if the radiative efficiency of
accretion is $10\%$. We also find no evidence that inferred BH masses and
accretion processes in $z>7$
quasars differ significantly from their near-identical counterparts at $z<3$.
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All authors Sarah E. I. Bosman, Javier Álvarez-Márquez, Frederick B. Davies, Klaudia Protušová, Joseph F. Hennawi, Jinyi Yang, Benedetta Spina, Luis Colina, Xiaohui Fan, Göran Östlin, Fabian Walter, Feige Wang, Martin Ward, Almudena Alonso Herrero, Aaron J. Barth, Silvia Belladitta, Leindert Boogaard, Karina I. Caputi, Thomas Connor, Dominika Ďurovčíková, Anna-Christina Eilers, Alejandro Crespo Gómez, Jens Hjorth, Hyunsung D. Jun, Danial Langeroodi, Weizhe Liu, Alessandro Lupi, Chiara Mazzucchelli, John P. Pye, Pierluigi Rinaldi, Paul van der Werf, Marta Volonteri
Earth and Planetary Astrophysics
Determining the impact of post-main-sequence stellar evolution on the transiting giant planet population
Edward M. Bryant and Vincent Van Eylen
The post-main sequence
evolution of
stars is expected to impact the
exoplanets residing on close-in orbits around them. Using photometric data from the TESS Full-Frame-Images we have performed a transit search for
exoplanets with post-main sequence hosts to search for the imprints of these impacts on the
giant planet population. We detect 130 short period
planets and candidates, thirty-three of which are newly discovered candidates, from a sample of 456,941 post-main sequence
stars spanning the evolutionary stages from the end of the main sequence to the bottom of the red
giant branch. We measure an occurrence rate of $0.28 \pm 0.04$% for short period
giant planets orbiting post-main sequence
stars. We also measure occurrence rates for two
stellar sub-populations, measuring values of $0.35 \pm 0.05$% for a sub-population representing the earliest stages of post-main sequence
evolution and $0.11^{+0.06}_{-0.05}$% for a sub-population of more evolved
stars. We show that the
giant planet occurrence rate decreases with increasing
stellar evolution stage, with a larger occurrence rate decrease observed for shorter period
planets. Our results are clear evidence that the population of short period
giant planets is being sculpted by the post-main sequence
evolution of the host
stars, and we conclude that this is most likely through the destruction of these
giant planets through the increased strength of
planet-
star tidal interactions resulting in the rapid
tidal decay of the
planets' orbits.
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Instrumentation and Methods for Astrophysics
The Exospace Weather Frontier
R. O. Parke Loyd, Evgenya L. Shkolnik, Joseph Lazio et al. (+26 more)
Space weather is among the most powerful and least understood forces shaping planetary atmospheres. In our
Solar System, we observe its effects directly: atmospheric escape, chemical disruption, and spectacular auroral displays. Yet for
exoplanets, we lack the tools and data to comprehensively assess the impacts of space weather, especially invisible elements like
stellar winds, coronal mass ejections, energetic particles, and variable interplanetary
magnetic fields. This problem lies at the intersection of four key fields: heliophysics, planetary science, astrobiology, and astrophysics. In 2023–2025, experts from these four fields convened at the W. M. Keck Institute for Space Studies to explore pathways for advancing the study of exospace weather. Organizing the subject into five core themes –
planets and their
stellar particle environments,
stellar magnetism and space weather modeling, quasi-steady
stellar winds, transient events, and programmatic pathways – our team synthesized concepts from across relevant fields and identified a wide array of opportunities for progress. This report is the product of that effort. It assembles cross-disciplinary knowledge; highlights outstanding theoretical challenges; explores promising innovations in observation, modeling, methodology, and instrumentation; and makes recommendations for accelerating community-wide progress. Together, these lay out a path to transforming the challenging, yet tractable problem of exospace weather into a foundational element of our understanding exoplanetary systems, and our own
Solar System, in their entirety.
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All authors R. O. Parke Loyd, Evgenya L. Shkolnik, Joseph Lazio, Gregg W. Hallinan, Julián Alvarado-Gómez, Laura Amaral, Ivey Davis, Alison Farrish, James Green, Dave Brain, Bin Chen, Christina Cohen, Shannon Curry, Karin Dissauer, Arika Egan, Nat Gopalswamy, Guillaume Gronoff, Shadia Habbal, Renyu Hu, Meng Jin, James Paul Mason, Ruth Murray-Clay, Kosuke Namekata, Rachel Osten, Antígona Segura, Astrid Veronig, Aline Vidotto, Maurice Wilson, Yu Xu
Astrophysics of Galaxies
Searching Within Galaxies for the Earliest Signs of Quenching With Spatially Resolved Star Formation Histories in UVCANDELS Galaxies at z< 0.3
Charlotte Olsen, Eric Gawiser, Charlotte Welker et al. (+18 more)
Understanding the complicated processes that regulate
star formation and cause a
galaxy to become quiescent is key to our comprehension of
galaxy evolution. We used eight well resolved
star-forming z$<$ 0.3
galaxies from the UVCANDELS survey, where a total of 10 HST bands including UV follow up in UVIS/F275W allow us to reconstruct the
star formation histories (SFHs) of regions across each
galaxy. This approach provides a powerful tool to explore the spatio-temporal connection between
star formation and
galaxy evolution. The spatial and temporal profiles of
stellar mass and
star formation rate surface density were obtained from the SFHs of these regions. We measure scaling relations and projected radial profiles of regions within each
galaxy at the time of observation and at 1 Gyr lookback time, noting possible trends in the
evolution. By comparing the change in
star formation over time we can infer the timing and location of
star formation and see early signs of
star formation shut off before quenching occurs. We compared the
star formation rate density –
stellar mass density scaling relations for individual
galaxies as they evolve from 1 Gyr lookback time. The correlation lines pivot around a log-
stellar mass surface density of 7.25 [$M_\odot$ $kpc^{-2}$] may be evidence of a self-regulating process on these scales. Radial profiles of
galaxy Log sSFR show an overall decrease over 1 Gyr, but five
galaxies show a greater change in Log sSFR at the outskirts than the center indicating a possible early onset of quenching in these
galaxies.
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All authors Charlotte Olsen, Eric Gawiser, Charlotte Welker, Harry Teplitz, Kartheik Iyer, Xin Wang, Marc Rafelski, Rogier A. Windhorst, Anton Koekemoer, Anahita Alavi, Ben Sunnquist, Norman Grogin, Yicheng Guo, Christopher J. Conselice, L. Y. Aaron Yung, Kalina Nedkova, Bahram Mobasher, Ray A. Lucas, Vihang Mehta, Y. Sophia Dai, Jonathan P. Gardner
Earth and Planetary Astrophysics
From thermal to magnetic driving: spectral diagnostics of simulation-based magnetothermal disc wind models
Michael L. Weber, Eleftheria Sarafidou, Christian Rab et al. (+2 more)
Disc winds driven by thermal and
magnetic processes are thought to play a critical role in protoplanetary disc
evolution. However, the relative contribution of each mechanism remains uncertain, particularly in light of their observational signatures. We investigate whether spatially resolved emission and synthetic spectral line profiles can distinguish between thermally and magnetically driven winds in protoplanetary discs. We modelled three disc wind scenarios with different levels of magnetisation: a relatively strongly magnetised wind ($\beta$4), a rather weakly magnetised wind ($\beta$6), and a purely photoevaporative wind (PE). Using radiative transfer post-processing, we generated synthetic emission maps and line profiles for [OI] 6300 Å, [NeII] 12.81 $\mathrm{\mu}$m, and o-H2 2.12 $\mathrm{\mu}$m, and compared them with observations. The $\beta$4 model generally produces broader and more blueshifted low-velocity components across all tracers, consistent with compact emission regions and steep velocity gradients. The $\beta$6 and PE models yield narrower profiles with smaller blueshifts, in better agreement with most observed narrow low-velocity components (NLVCs). We also find that some line profile diagnostics, such as the inclination at maximum centroid velocity, are not robust discriminants. However, the overall blueshift and full-width at half-maximum (FWHM) of the low-velocity components provide reliable constraints. The $\beta$4 model reproduces the most extreme blueshifted NLVCs in observations, while most observed winds are more consistent with the $\beta$6 and PE models. Our findings reinforce previous conclusions that most observed NLVCs are compatible with weakly magnetised or purely photoevaporative flows. The combination of line kinematics and emission morphology offers meaningful constraints on wind-driving physics.
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All authors Michael L. Weber, Eleftheria Sarafidou, Christian Rab, Oliver Gressel, Barbara Ercolano
Cosmology and Nongalactic Astrophysics
Reliable Parameter Inference for the Epoch of Reionization using Balanced Neural Ratio Estimation
Diego González-Hernández, Molly Wolfson and Joseph F. Hennawi
We present an application of the Balanced Neural Ratio Estimation (BNRE)
algorithm to improve the statistical validity of parameter estimates used to characterize the Epoch of Reionization, where the common assumption of a multivariate Gaussian likelihood leads to overconfident and biased posterior distributions. Using a two-parameter model of the Ly$\alpha$ forest autocorrelation function, we show that BNRE yields posterior distributions that are significantly better calibrated than those obtained under the Gaussian likelihood assumption, as verified through the Test of Accuracy with Random Points (TARP) and Simulation-Based Calibration (SBC) diagnostics. These results demonstrate the potential of Simulation-Based Inference (SBI) methods, and in particular BNRE, to provide statistically robust parameter constraints within existing astrophysical modeling frameworks.
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Solar and Stellar Astrophysics
Cesam2k20: A code for a new generation of stellar evolution models. I. Description of the code
L. Manchon, M. Deal, J. P. C. Marques et al. (+1 more)
We present Cesam2k20, the latest version of the hydrostatic
stellar evolution code CESAM originally developed by P. Morel and collaborators. Over the last three decades, it has undergone many improvements and has been extensively tested against other
stellar evolution codes before being selected to compute the first-generation grid of
stellar models for the PLATO mission. Among all the developments made thus far, Cesam2k20 now implements state-of-the-art models for the transport of chemical elements and angular momentum. It was recently made publicly available with an ecosystem of other codes interfaced with it: 1D and 2D oscillation codes ADIPLS and ACOR, optimisation program OSM, and Python utility package pycesam. This paper recalls the numerical peculiarities of Cesam2k20, namely, the use of a collocation method where the structure variables are decomposed as piecewise
polynomials projected on a B-spline basis. Here, we review the options available for modelling the different physical processes. In particular, we illustrate the improvements made in the transport of chemical elements and angular momentum with a series of standard and non-standard
solar models.
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All authors L. Manchon, M. Deal, J. P. C. Marques, Y. Lebreton
Solar and Stellar Astrophysics
Visualization of High Dynamic Range Solar Imagery and the Radial Histogram Equalizing Filter
Chris Gilly and Steven Cranmer
Standard visualizations of Extreme Ultraviolet (EUV)
solar imagery often fail to convey the full complexity of the Sun's corona, especially in faint off-limb regions. This can leave the misleading impression of the Sun as a bright ball in a dark void, rather than revealing it as the dynamic, structured source of the
solar wind and space weather. A variety of enhancement
algorithms have been developed to address this challenge, each with its own strengths and tradeoffs. We introduce the Radial Histogram Equalizing Filter (RHEF), a novel hybrid technique that optimizes contrast in high dynamic range
solar images. By combining the spatial awareness of radial graded filters with the perceptual benefits of histogram equalization, RHEF reveals faint coronal structures and works out of the box – without requiring careful parameter tuning or prior
dataset characterization. RHEF operates independently on each frame, and it enhances on-disk and off-limb features uniformly across the field of view. For additional control, we also present the Upsilon redistribution function – a symmetrized cousin of gamma correction – as an optional post-processing step that provides intuitive programmatic tonal compression. We
benchmark RHEF against established methods and offer guidance on filter selection across various applications, with examples from multiple
solar instruments provided in an appendix. Implemented and available in both Python sunkit_image and IDL, RHEF enables immediate improvements in
solar coronal visualization.
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Astrophysics of Galaxies
Solving the cooling flow problem with combined jet-wind AGN feedback
Aoyun He, Feng Yuan, Suoqing Ji et al. (+6 more)
Active
galactic nucleus (AGN) feedback is widely viewed as the most promising solution to the long-standing cooling flow problem in
galaxy clusters, yet previous models prescribe jet properties inconsistent with
accretion physics. We perform an idealized hydrodynamic simulation of a
galaxy cluster with no merger history and a relaxed state, with its other properties similar to the Perseus cluster using the MACER framework, incorporating both jets and winds whose properties are constrained by general relativistic magnetohydrodynamic simulations of black hole
accretion and observations. The combined feedback reproduces key observables, including cold gas mass,
star formation rate, thermodynamic radial profiles, and black hole growth, while jet-only or wind-only models fail. The success arises from
turbulence driven by jet-wind shear that enhances kinetic-to-thermal energy conversion, boosting heating efficiency by factors of three and six relative to wind-only and jet-only cases, respectively.
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All authors Aoyun He, Feng Yuan, Suoqing Ji, Minhang Guo, Yuan Li, Haiguang Xu, Ming Sun, Haojie Xia, Yuanyuan Zhao
Instrumentation and Methods for Astrophysics
Development of Silicon Micromachined Waveguide Filter-Banks for On-Chip Spectrometers
Matthew A. Koc, Jason Austermann, James Beall et al. (+4 more)
Development of high-speed, spatial-mapping spectrometers in the millimeter and far-infrared frequencies would enable entirely new research avenues in astronomy and cosmology. An "on-chip" spectrometer is one such technology that could enable Line Intensity Mapping. Recent work has shown the promise of high-speed imaging; however, a limiting factor is that many of these devices suffer from low optical efficiency. Here we present the fabrication of a metalized, Si waveguide filter-bank fabricated using deep reactive ion etching for use in millimeter spectroscopy. Our design simultaneously provides high-density pixel packing, high optical efficiency, high spectral resolution, and is readily compatible with simple and multiplexable MKID arrays. Gold plated test waveguide and filter show excellent match to simulations with a measured resolving power of 263 and a loss quality factor of 1116 at room temperature. The results show promise for extending the measurements to larger, multi-wavelength designs.
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All authors Matthew A. Koc, Jason Austermann, James Beall, Johannes Hubmayr, Joel N. Ullom, Michael Vissers, Jordan Wheeler
Cosmology and Nongalactic Astrophysics
Measuring the expansion history of the Universe with DESI Cosmic Chronometers
S.I. Loubser
Studying large samples of massive, passively evolving
galaxies (called
cosmic chronometers, CC) provides us with the unique ability to measure the Universe's expansion history without assuming a cosmological model. The Dark Energy Spectroscopic Instrument (DESI) DR1 is currently the largest, publicly available, homogeneous set of
galaxies with reliable spectroscopic
redshifts, and covers a wide range in
redshift. We extracted all massive
galaxies (
stellar mass $\log M_{\star}/M_{\odot} > 10.75$, and velocity dispersion $\sigma > 280$ km s$^{-1}$), with no emission in [OII] $\lambda$ 3727 $\r{A}$, with reliable
redshifts as well as reliable D4000$_{\rm n}$ measurements from DR1. From this sample of 360 000 massive, passive
galaxies, we used D4000$_{\rm n}$ and the method of
cosmic chronometers to get three new direct, independent measurements of $H(z)=$ 88.48 $\pm\ 0.57(\rm stat) \pm 12.32(\rm syst)$, $H(z)=$ 119.45 $\pm\ 6.39(\rm stat) \pm 16.64(\rm syst)$, and $H(z)= 108.28 \pm 10.07(\rm stat) \pm 15.08(\rm syst)$ $\rm km\ s^{-1}\ Mpc^{-1}$ at $z=0.46$, $z=0.67$, and $z=0.83$, respectively. This sample, which covers $0.3 < z < 1.0$, is the largest CC sample to date, and we reach statistical uncertainties of 0.65$\%$, 5.35$\%$, and 9.30$\%$ on our three measurements. Our measurements show no significant tension with the $\textit{Planck}$ $\Lambda$CDM cosmology. In our analysis, we also illustrate that even amongst samples of massive, passive
galaxies, the effect of downsizing can clearly be seen.
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Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Observational tests of the conformal osculating Barthel-Kropina cosmological model
Himanshu Chaudhary, Rattanasak Hama, Tiberiu Harko et al. (+2 more)
We consider detailed cosmological tests of dark energy models obtained from the general conformal transformation of the Kropina metric, representing an $(\alpha,\beta)$-type Finslerian geometry. In particular, we restrict our analysis to the osculating Barthel Kropina geometry. The Kropina metric function is defined as the ratio of the square of a Riemannian metric $\alpha$ and of the one-form $\beta$. In this framework, we also consider the role of the conformal transformations of the metric, which allows us to introduce a family of conformal Barthel-Kropina theories in an osculating geometry. The models obtained in this way are described by second-order field equations, in the presence of an effective scalar field induced by the conformal factor. The generalized Friedmann equations of the model are obtained by adopting for the Riemannian metric $\alpha$ the Friedmann Lemaitre Robertson Walker representation. In order to close the cosmological field equations, we assume a specific relationship between the component of the one-form $\beta$ and the conformal factor. With this assumption, the cosmological
evolution is determined by the initial conditions of the scalar field and a single free parameter $\gamma$ of the model. The conformal Barthel Kropina cosmological models are compared against several observational
datasets, including
Cosmic Chronometers, Type Ia
Supernovae, and
Baryon Acoustic Oscillations, using a Markov Chain Monte Carlo (MCMC) analysis, which allows the determination of $\gamma$. A comparison with the predictions of standard $\Lambda$CDM model is also performed. {Our results indicate that the conformal osculating Barthel Kropina model can be considered as a successful, and simple, alternative to standard cosmological models.
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All authors Himanshu Chaudhary, Rattanasak Hama, Tiberiu Harko, Sorin V. Sabau, Shibesh Kumar Jas Pacif
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Quintessence
Artur Alho, Elsa Bernholm and Claes Uggla
Recent observations suggest that the accelerated expansion of the Universe at late times is caused by a temporally changing dark energy component, rather than the constant one in the standard $\Lambda$CDM scenario. In this context quintessence, i.e. a canonical scalar field minimally coupled to
gravity, plays a prominent role. There are, however, three main types of quintessence models: thawing quintessence, scaling freezing quintessence, and tracking quintessence. Dynamical systems reformulations of the field equations for a broad set of scalar field potentials, including some new ones, allow us to use dynamical systems methods to derive global and asymptotic features, visualised in bounded state space pictures clearly illustrating the relationships and properties of the different types of quintessence, clarifying initial data issues, and yielding simple and accurate approximations.
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Solar and Stellar Astrophysics
Rachel A. Osten, Adam F. Kowalski, Suzanne Hawley et al. (+4 more)
We present the results of a coordinated campaign to observe
radio and optical
stellar flares from the nearby M
dwarf flare star EV~Lac. From a total of 27 hours of
radio and 29 hours of optical observations, we examine the correspondence of the action of accelerated electrons of different energies in two distinct regions of the
stellar atmosphere. We find that out of 9 optical
flares with suitable
radio coverage, only four have plausible evidence for a
radio response. Optical photometric properties cannot predict which
flares will have a
radio response. From
flares with time-resolved optical spectroscopy available, optical-only
flares have similar implied electron distributions, while those with
radio responses better correlate with higher low-energy cutoffs. The optical
flares with a
radio response all exhibit a delay between the optical and
radio peaks of $\approx$1-7 minutes, with the optical
flare peaking earlier in all cases. This likely indicates multiple loops are involved in the event, and/or the different impacts on electrons trapped in a
magnetic loop (producing
radio emission), versus those directly precipitating from the loop (producing the optical
flare). We also remark on the
radio spectral index behavior at early times for the largest
radio flare observed in this study, which we interpret as evidence for increased opacity from a chromospheric evaporation front.
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All authors Rachel A. Osten, Adam F. Kowalski, Suzanne Hawley, Isaiah I. Tristan, Sarah J. Schmidt, Ben Tofflemire, Eric Hilton
Astrophysics of Galaxies
The effect of mass and morphology on the mass assembly of galaxies
A. Camps-Fariña, R. M. Mérida, P. Sánchez Blázquez et al. (+1 more)
The pace at which
galaxies grew into their current
stellar masses and how this growth is regulated is still not fully understood, nor is the role that morphology plays in this process. We applied full spectral fitting techniques with pyPipe3D to the MaNGA sample to obtain its
star formation and
stellar mass histories and used these to investigate the mass assembly of
galaxies by measuring how their specific
star formation correlates to their
stellar mass at different look-back times. We find that the correlation between these two parameters was shallower in the past.
Galaxies used to have similar mass doubling times and the current negative correlation between the specific
star formation and M* is primarily due to more massive
galaxies 'dropping' off the main sequence earlier than less massive ones. Additionally, selecting the
galaxies into bins based on their present-day morphology shows a segregation in specific
star formation rate (sSFR) that is maintained even at high look-back times, showing that the factors that determine which morphology a
galaxy ends up in are in place at very early times. Similarly, selecting them based on their current
star formation status shows that, on average, currently retired
galaxies used to have slightly a higher sSFR before the drop-off, whereas
galaxies that have continued to form
stars until today had a lower sSFR initially. We compare our results to a set of
cosmic surveys, finding partial agreement in our results with several of them, though with significant offsets in
redshift. Finally, we discuss how our results fit with certain theoretical models on
galaxy evolution as well as cosmological simulations.
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All authors A. Camps-Fariña, R. M. Mérida, P. Sánchez Blázquez, S. F. Sánchez
Earth and Planetary Astrophysics
Lunar Time
Pascale Defraigne, Frédéric Meynadier and Adrien Bourgoin
The regain of interest in Moon exploration has substantially grown in the last years. For this reason, the space agencies consider the development of a precise
navigation and positioning service similar to the Earth GNSS. Aiming at some meter accuracy, this requires to set up a relativistic lunar reference frame, with an associated coordinate time. If the IAU already defined the Lunar Coordinate Time TCL, there is still some freedom in the choice of the coordinate timescale to be adopted as reference on or around the Moon. This paper proposes a trade-off analysis of different possible options for this reference time scale. It shows that TCL is the best option to be used as practical time reference on the Moon, without the need to define a new time scale based on a scaling of TCL.
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Solar and Stellar Astrophysics · Cross-listed from math.AP
Revisited for existence proof of optimal solution in Bernoulli free boundary problem using an energy-gap cost functional
Shiouhe Wang, Fang Shen, Yi Yang et al. (+1 more)
Bernoulli free boundary problem is numerically solved via shape optimization that minimizes a cost functional subject to state problems constraints. In \cite{1}, an energy-gap cost functional was formulated based on two auxiliary state problems, with existence of optimal solution attempted through continuity of state problems with respect to the domain. Nevertheless, there exists a corrigendum in Eq.(48) in \cite{1}, where the boundedness of solution sequences for state problems with respect to the domain cannot be directly estimated via the Cauchy-Schwarz inequality as Claimed. In this comment, we rectify this proof by Poincaré-Friedrichs inequality.
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All authors Shiouhe Wang, Fang Shen, Yi Yang, Xueshang Feng
High Energy Astrophysical Phenomena · Cross-listed from gr-qc
GW231123 ringdown: interpretation as multimodal Kerr signal
Harrison Siegel, Nicole M. Khusid, Maximiliano Isi et al. (+1 more)
GW231123 is a short-duration, low-frequency gravitational wave signal consistent with a binary black hole coalescence and dominated by the merger-ringdown regime due to the high mass of the source. We demonstrate that fits of this ringdown signal using two quasinormal modes are statistically preferred over single-mode fits, for a broad range of fit start times. We also find that two-mode fits give remnant mass and
spin measurements consistent with those of the inspiral-merger-ringdown model NRSur7dq4, whereas one-mode fits struggle to do so. Agreement of our fits with those of NRSur7dq4 is achieved by labeling the two quasinormal modes as the ${(\ell,m)=(2,2)}$ and ${(2,0)}$ Kerr prograde fundamental modes. However, we find some indications that fits with the ${(2,1)}$ quasinormal mode instead of the ${(2,0)}$ mode may describe the data better, hinting at possible NRSur7dq4 error or other systematics. When fitting at early times near the estimated peak strain, we find that the inclusion of a third mode, an ${(\ell,m,n)=(2,2,1)}$ prograde overtone, improves consistency with fits at later times. Finally, we perform a test of general relativity by searching for deviations from the Kerr frequency spectrum. Setting issues of systematics aside, we validate the Kerr frequency and damping rate spectrum to within $\pm10\%$ at the 90$\%$ credible level using a fundamental mode fit, and we also report $\pm8\%$ constraints using a model with fundamental modes and an overtone fit at times near the peak strain. Understanding the systematic errors that may be affecting the most accurate analyses of GW231123 is crucial in the context of population and binary formation studies – our ${(2,1)}$ mode fits return a significantly higher remnant mass and
spin than all available inspiral-merger-ringdown models including NRSur7dq4, and this difference in parameter estimates may have astrophysical implications.
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All authors Harrison Siegel, Nicole M. Khusid, Maximiliano Isi, Will M. Farr
Solar and Stellar Astrophysics
Resonances and Stellar Cycles: Observations and Modelling
M.M. Katsova, F.A. Azizov, V.N. Obridko et al. (+2 more)
In the paper we discuss the possibility of the influence of parametric excitation, in particular, planetary gravitational interaction, on the behavior of
stellar magnetic activity cycles. Using the well-known Parker dynamo modeling, we demonstrate the doubtfulness of the fact that planetary rotation can be a determining factor in the formation of the cycle itself. However, we show that even a weak parametric influence can be sufficient to modulation of
magnetic field oscillations, and, in particular, to the occurrence of beats. This result is discussed in the context of the influence of Jupiter on the occurrence of maxima and minima of the
magnetic activity of our Sun.
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All authors M.M. Katsova, F.A. Azizov, V.N. Obridko, D.D. Sokoloff, E.V. Yushkov
Astrophysics of Galaxies
Benchmarking differential reddening in front of globular clusters
Csilla Kalup and László Molnár
Interstellar extinction is a major obstacle in determining accurate
stellar parameters from photometry near the
Galactic disk. It is especially true for globular clusters at low
galactic latitudes, which suffer from significant amounts of, and spatially variable reddening. Although differential reddening maps are available for tens of clusters, establishing and validating the absolute zero point of relative maps is a challenge. In this study, we present a new approach to determine and evaluate absolute reddening zero-points for
Galactic globular clusters by combining three-dimensional reddening maps with
Gaia DR3 RR Lyrae data. As a first case study, we investigate the low-latitude globular cluster M9. We compare the
Gaia photometry and color data of the cluster member RR Lyrae
stars to field RR Lyrae
stars with accurate parallaxes and whose photometric
metallicities match that of M9, as well as to theoretical models. We calculate the dereddened
Gaia colors for the M9
stars based on three zero points. We confirm that the original SFD map appears to be overcorrecting the reddening for at least some RR Lyrae
stars, albeit not excessively. In contrast, the 3D Bayestar map and the recalibrated version of the SFD map provide physically plausible reddenings, which we accept as lower and upper limits for M9, respectively. Our results provide a physically motivated reddening range for M9, and outline a methodology that can be directly extended to other globular clusters that are accessible to the
Gaia mission, and to other multicolor sky surveys, such as the Rubin Observatory.
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High Energy Astrophysical Phenomena · Cross-listed from nucl-th
A Bayesian Inference of Hybrid Stars with Large Quark Cores
Milena Albino, Tuhin Malik, Márcio Ferreira et al. (+1 more)
Neutron stars (NSs) are interesting objects capable of reaching densities unattainable on Earth. The properties of matter under these conditions remain a mystery. Exotic matter, including
quark matter, may be present in the NS core. In this work, we explore the possible compositions of NS cores, in particular, the possible existence of large
quark cores. We use the Relativistic Mean Field (RMF) model with nonlinear terms for the
hadron phase and the Nambu-Jona-Lasinio (NJL) model and Mean Field Theory of
Quantum Chromodynamics (MFTQCD) for the
quark phase. Through
Bayesian inference, we obtain different sets of equations: four sets with hybrid equations and one set with only the
hadron phase. We impose constraints regarding the properties of
nuclear matter, X-ray observational data from NICER, gravitational wave data from the binary
neutron star merger GW170817, perturbative QCD (pQCD) calculations, and causality. The MFTQCD allows for a phase transition to
quark matter at low densities, just above saturation density, while for the NJL sets, the phase transition occurs above twice the saturation density. As a result, the MFTQCD model predicts the presence of
quark matter in the inner core of 1.4 M$_\odot$ NSs, while NJL models suggest a low probability of
quark matter in the interior of a 1.4 M$_\odot$ NS. Both models predict the existence of
quark matter in 2 M$_\odot$ NSs. The slope of the mass-radius curve has been shown to carry information about the presence of
quark matter. In particular, a positive slope at 1.8 M$_\odot$ indicates the presence of non-nucleonic matter. A hybrid
star with a stiff
quark equation of state could explain a larger radius in more massive
stars, such as two
solar mass
stars, compared to canonical NSs.
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All authors Milena Albino, Tuhin Malik, Márcio Ferreira, Constança Providência
Earth and Planetary Astrophysics
The First Occurrence Rate Estimates for Exoplanets in Small-Separation Binary Star Systems: Planet Occurrence is Suppressed in Binary Stars
Kendall Sullivan, Anne Dattilo and Natalie M. Batalha
Exoplanet occurrence rates facilitate comparisons between observations of
planets and theoretical models of
planet formation. Despite their deductive power,
exoplanet occurrence rates for half the
stars in the sky are missing because occurrence rate studies systematically exclude binary
star systems. We assembled a large sample of high-likelihood binaries from the Kepler mission to calculate occurrence rates for circumstellar (S-type)
planets in small-separation binary
star systems ($\lesssim 100$ au) for the first time. For a sample of high-likelihood small-separation binaries, we found binaries to host 58% fewer
planets per system than single
stars to 11.4$\sigma$ significance within 1-4 $R_{\oplus}$ and 1-50 d, and 50% fewer
planets compared to single
stars when integrating over the full parameter space of 1-10 $R_{\oplus}$ and 1-100 d to 3.8$\sigma$ significance.. We found no evidence for a radius valley or radius cliff, instead detecting a smooth decline in
planet occurrence with increasing planetary radius. The difference between the single-
star planet radius distribution and the binary-
star planet radius distribution is 4.3$\sigma$ significant from a Kolomogorov-Smirnov test. These results suggest significantly different
planet formation and survival outcomes in binaries compared to single
stars, and support other studies that have measured a deficit of observed
planets in binary
star systems.
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High Energy Astrophysical Phenomena
Using Deep Learning for Robust Classification of Fast Radio Bursts
Rohan Arni, Carlos Blanco and Anirudh Prabhu
While the nature of fast
radio bursts (FRBs) remains unknown, population-level analyses can elucidate underlying structure in these signals. In this study, we employ deep learning methods to both classify FRBs and analyze structural patterns in the latent space learned from the first CHIME catalog. We adopt a Supervised Variational Autoencoder (sVAE) architecture which combines the representational learning capabilities of Variational Autoencoders (VAEs) with a supervised classification task, thereby improving both classification performance and the interpretability of the latent space. We construct a learned latent space in which we perform further dimensionality reduction to find underlying structure in the data. Our results demonstrate that the sVAE model achieves high classification accuracy for FRB repeaters and reveals separation between repeater and non-repeater populations. Upon further analysis of the latent space, we observe that dispersion measure excess, spectral index, and spectral running are the dominant features distinguishing repeaters from non-repeaters. We also identify four non-repeating FRBs as repeater candidates, two of which have been independently flagged in previous studies.
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