Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Ultralight time-oscillating scalars from magnetized compact stars: electrophilic radiation and photon propagation effects
Tanmay kumar Poddar and Gaetano Lambiase
Ultralight scalars with electrophilic couplings to the time-dependent Goldreich-Julian charge density of magnetized compact
stars can be radiated from their magnetospheres, contributing to
pulsar spin-down. Coupling to the time-independent component of the charge density instead generates a quadrupolar scalar field profile, which may influence the orbital dynamics of binary systems. Such scalars can also interact with the time-varying electromagnetic fields of magnetized
stars, modifying
photon propagation and inducing observable effects in the
redshift and residual time-delay measurements, as well as corrections to the background electromagnetic fields. We investigate these phenomena for the Crab
pulsar, SGR 1806-20, and GRB 080805A. Using spectral and timing observations, we derive constraints on the scalar-electron and scalar-
photon couplings. While the bounds obtained on the scalar-electron coupling from
pulsar spin-down are weaker than existing limits, electromagnetic radiation measurements yield the strongest astrophysical constraints to date on the scalar-
photon coupling. Compact
stars with stronger surface
magnetic fields and observations at lower
photon frequencies can improve these bounds by several orders of magnitude.
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Astrophysics of Galaxies
Low-mass stars dominate the hot (0.7 keV) Galactic X-ray emission
G. Ponti, M. C. H. Yeung, G. Stel et al. (+12 more)
The circumgalactic medium (CGM) of the Milky Way is composed of a tenuous atmosphere filled with multi-phase
plasma, including a warm-hot virialised component. Recent studies suggest a much hotter (~0.7 keV) super-virial component detected in both absorption and emission. We want to shed light on the nature of this putative super-virial component. We analysed the X-ray background as observed by SRG/eROSITA over the entire western
Galactic hemisphere. We show that low-mass
stars provide a large fraction of the 0.7 keV emission. Indeed, a tight correlation is found between the surface brightness of the 0.7 keV emission and the mass distribution of the Milky Way across a large portion of the western
Galactic hemisphere. The correlation coefficient implies an X-ray luminosity per unit of
stellar mass comparable to that of the average low-mass
stars within 10 pc of the Sun, suggesting that unresolved M
dwarfs and F, G, and K type
stars dominate the 0.7 keV emission. This emission is asymmetric with respect to the
Galactic plane, influenced by the asymmetric distribution of nearby
star-forming regions, and broadly consistent with the known offset of the Sun above the
Galactic midplane. The remaining signal might be produced by the cumulative emission of
stars of different types or ages, in addition to other sources (e.g. hot interstellar medium,
Galactic corona, etc.). Assuming that the putative residual hot super-virial atmosphere is homogeneous and has a spherical beta profile with slope $\beta=0.4$, we constrain its density at 10 kpc to be $n_e<4\times10^{-4}$~cm$^{-3}$. Our findings may help refine models of the circumgalactic medium around external
galaxies, advancing our understanding of hot
baryon flows and
galaxy evolution.
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All authors G. Ponti, M. C. H. Yeung, G. Stel, N. Locatelli, X. Zheng, B. Stelzer, A. Merloni, M. Caramazza, E. Magaudda, M. Sasaki, K. Dennerl, T. H. Reiprich, A. Schwope, W. Becker, M. Freyberg
Cosmology and Nongalactic Astrophysics
pop-cosmos: Forward modeling KiDS-1000 redshift distributions using realistic galaxy populations
Boris Leistedt, Hiranya V. Peiris, Anik Halder et al. (+13 more)
The accuracy of the cosmological constraints from Stage~IV
galaxy surveys will be limited by how well the
galaxy redshift distributions can be inferred. We have addressed this challenging problem for the Kilo-Degree Survey (KiDS)
cosmic shear sample by developing a forward-modeling framework with two main ingredients: (1) the pop-cosmos generative model for the evolving
galaxy population, calibrated on Spitzer IRAC $\textit{Ch.\,1}<26$
galaxies from COSMOS2020; and (2) a data model for noise and selection, machine-learned from the SURFS-based KiDS-Legacy-Like Simulations (SKiLLS). Applying KiDS tomographic binning to our synthetic photometric data, we infer
redshift distributions in each of five bins directly from the population and data models, bypassing the need for spectroscopic reweighting. Keeping the data model fixed, we compare results using two different
galaxy population models: pop-cosmos; and shark, the semi-analytic
galaxy formation model used in SKiLLS. In the first ($0.1<z<0.3$) and last ($0.9<z<1.2$) tomographic bins we find systematic differences in the mean
redshifts of $\Delta z\sim0.05$-$0.1$, comparable to the reported uncertainties from spectroscopic reweighting methods. This work paves the way for accurate
redshift distribution calibration for Stage~IV surveys directly through forward modeling, thus providing an independent cross-check on spectroscopic-based calibrations which avoids their selection biases and incompleteness. We will use the pop-cosmos
redshift distributions in an upcoming full KiDS cosmology reanalysis.
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All authors Boris Leistedt, Hiranya V. Peiris, Anik Halder, Stephen Thorp, Daniel J. Mortlock, Arthur Loureiro, Justin Alsing, Gurjeet Jagwani, Madalina N. Tudorache, Sinan Deger, Joel Leja, Benedict Van den Bussche, Angus H. Wright, Shun-Sheng Li, Konrad Kuijken, Hendrik Hildebrandt
Astrophysics of Galaxies
Dynamical Systematics for Time Delay Lenses and the Impact on the Hubble Constant
R. Forés-Toribio, C. S. Kochanek and J. A. Muñoz
While time-delay lenses can independently probe $H_0$, the estimates are degenerate with the convergence of the lens near the Einstein radius. Velocity dispersions, $\sigma$, can be used to break the degeneracy, with uncertainties $\Delta H/H_0 \propto \Delta\sigma^2/\sigma^2$ ultimately limited by systematic uncertainties in the kinematic measurements - measuring $H_0$ to 2% requires $\Delta\sigma^2/\sigma^2 < 2\%$. Here we explore a broad range of potential systematic uncertainties affecting eight time-delay lenses used in cosmological analyses. We find that: (1) The characterization of the PSF in both absolute scale and shape is important, with biases in $\Delta\sigma^2/\sigma^2$ up to $1$-$5\%$ for ground-based observations. Small miscenterings of the lens are less important. (2) The difference between the measured velocity dispersion and the mean square velocity needed for the Jeans equations is important, with up to $\Delta\sigma^2/\sigma^2 \sim 2$-$6\%$. (3) The choice of anisotropy models is important with maximum changes of $\Delta\sigma^2/\sigma^2 \sim2$-$18\%$. Biases may be minimized by using models that reproduce the $h_4$ velocity moments typical of early-type
galaxies. (4) Small differences between the true
stellar mass distribution and the model light profile matter ($\Delta\sigma^2/\sigma^2 \sim 1$-$10\%$), with radial color gradients further complicating the problem. The Jeans equations for mixed
stellar populations imply that the correct profile is a population line equivalent width weighting corresponding to no broad band filter profile. Finally, the homogeneity of the early-type
galaxy population means that many dynamically related parameters must be marginalized over the lens sample as a whole and not over individual lenses.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-th
Electromagnetic Couplings of Dark Domain Walls
Nemanja Kaloper
We extend Maxwell electrodynamics with a Chern–Simons coupling to a dark sector top form sourced by domain walls.
Cosmic birefringence can arise from a distinct mechanism in which
photon polarization is rotated when crossing
vacuum interfaces, rather than through adiabatic propagation in a background field. Ultrathin walls induce a finite, frequency-independent polarization rotation generated by an electromagnetic Chern-Simons term localized at the interface. The effect persists even in the absence of ultralight
axions or other propagating scalar degrees of freedom. For phenomenologically viable parameters, such walls can generate
cosmic microwave background polarization rotation at the level $\Delta\vartheta \sim 10^{-3}$ rad, providing a signature of the topological structure of the dark-sector
vacuum.
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High Energy Astrophysical Phenomena
Discovery of crested quasi-periodic eruptions following the most luminous SRG/eROSITA tidal disruption event
Pietro Baldini, Arne Rau, Andrea Merloni et al. (+11 more)
We report the discovery of complex flaring activity from the
galactic nucleus hosting the five-year-old
tidal disruption event eRASSt J234402.9-352640 (J2344). With Einstein Probe and XMM-Newton observations, we detected highly structured soft X-ray variability. Through temporal decomposition of the XMM-Newton light curve and time-resolved spectral analysis, we identified broad, thermal
flares recurring every $\sim$12 hours and lasting $\sim$2 hours, consistent with quasi-periodic eruptions (QPEs). Remarkably, these QPEs are accompanied by an unprecedented crest of hotter, shorter
flares, each lasting between 5 and 30 minutes. These
flares are predominantly found in the rising phases of the QPEs, although they also appear throughout the quiescence. These findings establish J2344 as a new member of the QPE emitter population and uncover a previously unobserved phenomenology that challenges current models of QPEs. In this letter, we present the phenomenological properties of this unique source and discuss possible interpretations within the framework of extreme-mass-ratio inspirals.
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All authors Pietro Baldini, Arne Rau, Andrea Merloni, Benny Trakhtenbrot, Riccardo Arcodia, Margherita Giustini, Giovanni Miniutti, Seán J. Brennan, Michael Freyberg, Paula Sánchez-Sáez, Iuliia Grotova, Zhu Liu, Tianying Lian, Kirpal Nandra
Astrophysics of Galaxies
pop-cosmos: Redshifts and physical properties of KiDS-1000 galaxies
Anik Halder, Hiranya V. Peiris, Stephen Thorp et al. (+8 more)
Principled
Bayesian inference of
galaxy properties has not previously been performed for wide-area weak
lensing surveys with millions of sources. We address this gap by applying the pop-cosmos generative model to perform spectral energy distribution (SED) fitting for 4 million KiDS-1000
galaxies. Calibrated on deep COSMOS2020 photometric data, pop-cosmos specifies a physically-motivated prior over the
galaxy population up to $z \simeq 6$ in
stellar population synthesis (SPS) parameter space. Using the Speculator SPS emulator with GPU-accelerated MCMC sampling, we perform full posterior inference at 8.2 GPU seconds per
galaxy, obtaining joint constraints on
galaxy redshifts and physical properties. We validate photometric
redshifts against $\sim\!185,\!000$ KiDS
galaxies cross-matched to DESI DR1 spectroscopic samples, achieving low bias ($2\times10^{-3}$), scatter ($\sigma_{\mathrm{MAD}}=0.03$), and outlier fraction (3.2%) for the Bright
Galaxy Survey, with comparable performance (bias $3\times10^{-2}$, $\sigma_{\mathrm{MAD}}=0.05$, 1.0% outliers) for luminous red
galaxies (LRGs). Within the LRG sample, we identify massive, dusty,
star-forming contaminants at $z \simeq 0.4$ satisfying standard colour selections for quenched populations. We infer trends in
stellar mass,
star formation,
metallicity, and
dust across five tomographic
redshift bins consistent with established scaling relations. Using specific
star formation rate constraints, we identify $\sim$7% of KiDS-1000
galaxies as quenched, versus 37% implied by conservative colour cuts. This enables the construction of weak
lensing samples defined by physical properties while mitigating intrinsic
alignment systematics and preserving statistical power. Our analysis validates pop-cosmos out-of-sample, establishing it as a scalable approach for
galaxy evolution and cosmological analyses with photometric surveys.
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All authors Anik Halder, Hiranya V. Peiris, Stephen Thorp, Boris Leistedt, Daniel J. Mortlock, Gurjeet Jagwani, Madalina N. Tudorache, Sinan Deger, Benedict Van den Bussche, Joel Leja, Angus H. Wright
Cosmology and Nongalactic Astrophysics
The local void model for the Hubble and BAO tensions
Indranil Banik, Harry Desmond, Vasileios Kalaitzidis et al. (+1 more)
The inconsistency between the locally inferred Hubble constant and the value inferred from the
cosmic microwave background assuming the $\Lambda$CDM cosmological model has persisted, turning into an important problem. An emergent underlying trend is that this Hubble tension is driven by data confined to the very low-
redshift Universe (typically $z < 0.15$). Most intermediate-
redshift measurements remain mutually consistent with $H_0^\mathrm{CMB}$, the $\Lambda$CDM expectation anchored by the CMB. This Perspective examines if a large local void can explain the Hubble tension and its appearance only at low $z$. For an observer residing within a large underdensity, such as the Milky Way inside the claimed KBC void, gravitationally induced
outflows and
redshift can inflate the locally inferred recession scale $cz'$ despite having $H_0 = H_0^\mathrm{CMB}$. We summarise evidence suggestive of a local underdensity from multi-wavelength
galaxy number counts, discuss the dynamical requirements implied by the amplitude of inferred bulk flows, and connect the solution to the emerging low-
redshift BAO distance anomaly ($\alpha_{\mathrm{iso}} < 1$). Previously published semi-analytic void models anticipated the observed
redshift dependence of BAO deviations and predict a rapid convergence to CMB-consistent expansion for $z \gtrsim 0.2$, aligning with reconstructions of $H_0(z)$ from BAO plus uncalibrated Type Ia
supernovae. We conclude by looking to future tests, including improved mapping of the local density and velocity field, fits to
galaxy distance catalogues at the field level, kinematic Sunyaev-Zel'dovich constraints on coherent
outflows, fast
radio bursts, and the long-term prospect of
redshift drift measurements as a direct probe of time-varying non-cosmological
redshift contributions.
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All authors Indranil Banik, Harry Desmond, Vasileios Kalaitzidis, Sergij Mazurenko
Cosmology and Nongalactic Astrophysics
An emulator for the ionizing photon mean free path in ultra-high resolution simulations: the implications of mean free path measurements for the reionization history
Hurum Maksora Tohfa, Christopher Cain, Matthew McQuinn et al. (+1 more)
Measurements of the mean free path of ionizing
photons from high-
redshift quasar spectra at $z \sim 5$-$6$ constrain the reionization history, but interpreting them requires modeling the kiloparsec-scale clumping that large-volume reionization simulations cannot resolve. We present a deep learning emulator for the mean free path (MFP) trained on high-resolution cosmological radiative transfer simulations of ionization fronts sweeping through small 2 comoving Mpc/h volumes. Using a residual multi-layer perceptron neural network, we predict the MFP at a given
redshift as a function of the reionization
redshift, photoionization rate, wavelength, and box-scale density, achieving a median relative error of 1.3% across nearly four orders of magnitude in MFP. Integrating its predictions over box-scale overdensity and an extended reionization history allows the emulator to predict the global MFP. We apply the emulator to extended reionization histories constrained by observed photoionization rates, finding that models prefer late reionization with substantial neutral fractions persisting at $z \lesssim 6$. Fitting a parametric ionization history yields a midpoint of reionization of $z_{\rm re} = 6.58\pm 1.2$ for reionization durations consistent with Planck and kinetic Sunyaev-Zeldovich constraints, and the universe being $10\%$ neutral still at $z < 5.8 ~(6.3)$ at 1~(2)$\sigma$. Global ionizing emissivity inferences using measurements of the photoionization rate and MFP plus our emulator, which avoids common power-law assumptions, suggest a factor of $2-3$ decline between $z = 6$ and $4.8$, in agreement with previous studies. Our method provides an efficient (and more converged) alternative to large-volume radiative-hydrodynamic simulations of reionization for interpreting MFP measurements, and can also serve as a subgrid prescription for the ionizing opacity within such simulations.
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All authors Hurum Maksora Tohfa, Christopher Cain, Matthew McQuinn, Anson D'Aloisio
Cosmology and Nongalactic Astrophysics
The Atacama Cosmology Telescope: Constraints on Local Non-Gaussianity from the ACT Cluster Catalog
Leonid Sarieddine, J. Richard Bond, Matt Hilton et al. (+8 more)
We derive constraints on local-type
primordial non-Gaussianity using the ACT DR6 Sunyaev–Zel'dovich cluster catalog. Modeling the
redshift- and mass-dependent number counts of 1,201 clusters in the 10,347~deg$^2$ Legacy region, and accounting for survey completeness, intrinsic SZ scatter, and a weak-
lensing-calibrated mass bias, we compute theoretical abundances using the Log–Edgeworth
halo mass function. Assuming $\Lambda$CDM with well-motivated external priors, we obtain $f_{\rm NL} = 55 \pm 125$ (68% CL), consistent with Gaussian initial conditions. These constraints probe comoving scales of $5$–$10~{\rm Mpc}~h^{-1}$, complementing CMB bispectrum and scale-dependent bias measurements, which do not reach such small scales. We also find evidence for a 16.4% residual mass bias, which, although heavily informed by our adopted priors, plays a key role in matching observed and predicted counts but has negligible effect on $f_{\rm NL}$ constraints. We briefly discuss robustness of the results under relaxed priors and the prospects for next-generation SZ and
lensing surveys to strengthen cluster-based tests of
primordial non-Gaussianity.
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All authors Leonid Sarieddine, J. Richard Bond, Matt Hilton, Raul Jimenez, Arthur Kosowsky, Kavilan Moodley, Bernardita Ried Guachalla, Cristóbal Sifón, Suzanne T. Staggs, Licia Verde, Edward J. Wollack
Earth and Planetary Astrophysics · Cross-listed from physics.space-ph
Where Does Tracing of Cosmic Ray in Real Atmosphere Terminate?
Du-Xin Zheng, Long Chen and Ran Huo
In backtracing simulations, which are widely employed to determine
cosmic-ray particle trajectories in the geomagnetic field, the atmosphere is typically approximated as an artificial sharp boundary at some low altitude where the traced trajectory terminates. In this paper, we extend beyond this simplified assumption and investigate two realistic physical processes that terminate
cosmic-ray particle propagation in the atmosphere: Bethe-Bloch energy loss mechanisms and hard scattering interactions with atmospheric atoms using total cross sections based on the Glauber-Gribov formalism. The former mechanism dominates at low
rigidities (for
protons below $\sim0.57$~GV), while the latter becomes dominant at higher
rigidities. Consequently, we introduce two dimensionless variables up to detailed numerical criteria: the relative
rigidity shift due to Bethe-Bloch effects ($\Delta\mathfrak{R}/\mathfrak{R}$), and the expected number of hard scattering events ($\langle N\rangle$). Using the corrected US Standard Atmosphere 1976 model, we demonstrate that the altitude dependence can be factorized as approximately $\exp(-0.14h/\textrm{km})$. Additionally, the effect of the local
curvature radius of the trajectory near perigee can be similarly factorized. Our calculations indicate that the simplified sharp-boundary altitude should be at least $50$ km with $\Delta\mathfrak{R}/\mathfrak{R}+\langle N\rangle\lesssim1$ for
protons, increasing by more than $15$ km for heavy
nuclei such as iron.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-th
Cosmological Correlator Discontinuities from Scattering Amplitudes
Chandramouli Chowdhury, Sadra Jazayeri, Arthur Lipstein et al. (+3 more)
Recent theoretical work has revealed that basic observables of
quantum field theory in de Sitter space, known as in-in or cosmological correlators, exhibit surprisingly simple mathematical structure reminiscent of scattering amplitudes in flat space. For many theories, this simplicity can be made manifest using a set of “cosmological dressing rules” which uplift flat-space Feynman diagrams to in-in correlators in de Sitter space by attaching auxiliary propagators to the interaction vertices. In this paper, we show that discontinuities of cosmological correlators with respect to internal energy variables can be obtained by applying auxiliary propagators to unitarity cuts of flat space Feynman diagrams. Moreover, discontinuities with respect to external energy variables can be obtained by cutting auxiliary propagators attached to Feynman diagrams. This observation in turn implies highly non-trivial constraints on cosmological correlators in the form of simple sum rules. We illustrate these ideas in a number of examples at tree-level and 1-loop for conformally coupled scalar theories, although they hold more generally. Finally, we show how to reconstruct cosmological correlators from their discontinuities using dispersion relations, providing a powerful new approach to computing cosmological observables by systematically reconstructing them from data uplifted from flat space.
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All authors Chandramouli Chowdhury, Sadra Jazayeri, Arthur Lipstein, Joe Marshall, Jiajie Mei, Ivo Sachs
Astrophysics of Galaxies
JWST Discovery of High-Velocity Mid-Infrared Ionized Outflows in Ultraluminous Infrared Galaxies F11119+3257 and F05189-2524
Jerome Seebeck, Kylie Yui Dan, Sylvain Veilleux et al. (+9 more)
Ultra-fast
outflows (UFOs) are thought to be a driving mechanism of large-scale winds driven by active
galactic nuclei, which cause significant
galactic feedback through quenching
star formation and regulating supermassive black hole growth. We present James Webb Space
Telescope (JWST) Mid-Infrared Instrument Medium-Resolution Spectrometer observations of two nearby ultraluminous infrared
galaxies (ULIRGs), F11119+3257 and F05189-2524, with
nuclear X-ray detected UFOs and kiloparsec-scale
outflow. These
galaxies show remarkably similar mid-infrared continuum and emission line features, notably including a high-velocity $v_{90}$ $\sim$ 4000 km s$^{-1}$
outflow detected in highly ionized neon emission lines, e.g., \nevi. In F05189-2524, we see a slightly slower biconical
outflow extending up to $\sim2$ kpc in the same neon emission lines. Both sources show evidence of AGN-driven radiative feedback through a deficit of rotational molecular hydrogen lines in the
nuclear region, $<$1 kpc from the central
quasar, but no clear evidence of any molecular gas entrained in the
quasar-driven
outflow. Energetic analysis shows that the warm ionized gas in both of these sources contributes minimally ($\sim0.1-5\%$) to the momentum
outflow rate of these sources and leaves the conclusions of previous literature unchanged: the energetics of these sources are broadly consistent with a momentum-conserving
outflow.
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All authors Jerome Seebeck, Kylie Yui Dan, Sylvain Veilleux, David Rupke, Eduardo Gonzalez-Alfonso, Ismael Garcia-Bernete, Weizhe Liu, Dieter Lutz, Marcio Melendez, Miguel Pereira-Santaella, Eckhard Sturm, Francesco Tombesi
Earth and Planetary Astrophysics
An Open Database of Lunar Regolith and Simulants Properties
Léonie Gasteiner, Naomi Murdoch and Olfa D'Angelo
Lunar regolith, the layer of unconsolidated material covering the Moon's surface, is central to the science and technology developed for the Moon, notably related to in-situ science investigations, resource utilization, surface infrastructure, and mobility systems. However, data on lunar soil properties remain fragmented across decades of mission reports, often in formats that are difficult to access or interpret. We present a newly compiled database of lunar regolith physical and geotechnical properties, including data collected by direct in-situ measurements from crewed missions, estimates inferred from surface interactions on the Moon and using remote sensing, as well as laboratory analyses of samples returned to Earth. The data collected include, among others, the angle of internal friction and cohesion (both Mohr-Coulomb model parameters), bulk density, and static bearing capacity, extracted from Luna and Apollo-era historical mission documentation all the way to contemporary Lunar programs. The
dataset specifies the type and location of the tests from which each value was obtained. Our database also includes parameters for lunar regolith simulants, providing a direct link between mission data and laboratory studies. In addition to centralizing this information, we developed a user interface that facilitates data
retrieval, filtering, and visualization. This interface enables users to generate customized plots for comparative analysis. Developed in an open-science perspective, it is designed to evolve in response to the community's needs. The database and its associated tools significantly enhance the accessibility and usability of lunar regolith and simulants data for scientific and engineering research.
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Instrumentation and Methods for Astrophysics · Cross-listed from hep-ex
Deep-Learning Denoising of Radio Signals for Ultra-High-Energy Cosmic-Ray Detection
Zhisen Lai, Oscar Macias, Aurélien Benoit-Lévy et al. (+2 more)
Extensive air showers initiated by ultra-high-energy
cosmic rays (UHECRs) produce broadband
radio pulses detectable over large areas, but
Galactic and instrumental backgrounds limit sensitivity near threshold. The
Giant Radio Array for
Neutrino Detection (GRAND) will use large arrays of autonomous
radio antennas to detect these air showers, requiring reliable recovery of weak pulses from background fluctuations. We develop a convolutional denoiser for GRAND-like
antenna traces that combines the time-domain waveform with the magnitude and phase of its
Fourier transform. The model is trained on $4.1\times10^5$ simulated traces constructed from ZHAireS air-shower emission, a reduced GRAND-like RF-chain response, and broadband noise normalized to the expected
Galactic-noise scale. In these simulations, denoising increases the detection probability at fixed false-positive rate and improves pulse-time recovery near threshold. The reconstructed peak amplitude is attenuated in the noise-dominated regime. This bias decreases as the pulse becomes better resolved, but a smaller channel-dependent bias persists at higher SNR. Near threshold, denoising therefore primarily improves candidate recovery and timing, while the measured amplitude response provides a basis for calibrating amplitude-sensitive observables.
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All authors Zhisen Lai, Oscar Macias, Aurélien Benoit-Lévy, Arsène Ferrière, Matías Tueros
Instrumentation and Methods for Astrophysics
Star Grazing with Alumina Grass: Antireflection coatings in the visible and near-infrared on IPX-Clear Microlenses assisted by Grass-like Alumina
Ishan Rana, Suvrath Mahadevan, Megan Delamer et al. (+1 more)
Two-
photon polymerization (2PP) enables fabrication of high-precision micro-optics with complex freeform geometries, opening a new parameter space for custom astronomical optics. Among available resins, the newly developed IPX Clear is particularly well suited for visible applications, offering high transmission across the visible-near-IR, low surface roughness, and excellent shape fidelity. However, Fresnel reflections at the air-
polymer interface introduce significant optical losses, which are detrimental in low-signal astronomy. Previous studies show grass-like alumina coatings on glass and fused silica can raise average transmission from 91.9% to approximately 99% over 400-900 nm. Here we explore the feasibility of Atomic Layer Deposition (ALD) to apply such coatings to IPX-Clear micro-optics over 400-1700 nm. Grass-like alumina anti-reflective (AR) coatings can approximate the ideal index condition by creating a gradual refractive-index transition from air to bulk IPX Clear, suppressing surface reflections. While grass-like coatings are established on bulk optics and conformal ALD films have been applied to 2PP micro-optics, we demonstrate - for the first time - alumina grass on 2PP microlenses made with the new IPX-Clear resin. We discuss key challenges and process steps, and observe that alumina-grass-coated microlenses lose only approximately 0.3% of
photons to reflection in the 400-850 nm range. Future work will test performance across the full 400-1700 nm band and explore improved environmental resilience, e.g., a SiO2 overcoat. Combined with the high optical transparency of IPX Clear, these coatings enable custom-designed, highly efficient microlenses for astronomical applications.
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All authors Ishan Rana, Suvrath Mahadevan, Megan Delamer, Ceiwynn Longworth
Solar and Stellar Astrophysics
Temporal variations of solar inertial mode parameters from GONG (2002-2024) and HMI (2010-2024): Rossby modes ($3 \leq m \leq 16 $) and $m=1$ high-latitude mode
B Lekshmi, Zhi-Chao Liang, Laurent Gizon et al. (+2 more)
We studied the temporal
evolution of
solar inertial modes over the
solar cycle using observations from GONG and SDO/HMI. We focused on the high-latitude mode with azimuthal wavenumber $m=1$ and the equatorial Rossby modes with $3 \le m \le 16$. We used horizontal flow maps near the
solar surface from GONG and HMI ring-diagram pipelines at a cadence of approximately one day, covering the period 2002-2024. The data were divided into overlapping 4-year windows, with central times separated by six months. Within each time window and for each inertial mode, we measured the frequency and power of the mode from GONG and HMI data. We find good agreement between GONG and HMI measurements throughout their overlapping period from 2010 to 2024. In general, the magnitude of the frequency variations increases with increasing $m$, and relative changes in mode power typically exceed 100%. For the $m=1$ high-latitude mode, the measured power is anticorrelated with the sunspot number (SSN), while its frequency shows no significant temporal variation. For the equatorial Rossby modes, the frequencies are generally anticorrelated with the SSN, whereas the mode powers tend to correlate positively with the SSN. An exception is the $m=3$ equatorial Rossby mode, whose mode power is strongly anticorrelated with the SSN, in contrast to the other equatorial Rossby modes, highlighting its distinct behavior. We find that the frequencies and power of the Sun's inertial modes have varied significantly on
solar-cycle timescales over the past 23 years. The mode parameters are however not uniformly synchronized with the SSN; variations are observed both between modes and from one
solar cycle to the next, with some of the differences likely reflecting observational uncertainties. The sensitivity of inertial modes to
solar-cycle changes indicates their potential as a diagnostic of
solar interior dynamics and magnetism.
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All authors B Lekshmi, Zhi-Chao Liang, Laurent Gizon, Jordan Philidet, Kiran Jain
Solar and Stellar Astrophysics · Cross-listed from physics.space-ph
Generation and Expansion-Driven Growth of Switchbacks in the Outer Solar Corona and Solar Wind
Nikos Sioulas, Marco Velli, Chen Shi et al. (+6 more)
We analyze Parker
Solar Probe and
Solar Orbiter measurements of
magnetic-field reversals (“switchbacks”) across the Alfvén surface ($M_a\simeq 1$), where $M_a$ is the Alfvén Mach number. The reported “sub-Alfvénic switchback dropout” follows from two diagnostic biases: conditioning on an instantaneous $M_a$, which is transiently elevated above unity by radial-velocity enhancements during large-amplitude Alfvénic rotations, and short-window local-mean backgrounds that partially track these rotations and suppress deflection angles. Treating $M_a$ as a bulk-stream property via rolling medians and referencing deflections to event-independent backgrounds – a Parker-spiral direction or a sufficiently long rolling median – recovers sub-Alfvénic switchbacks systematically. The mean deflection $\langle \theta \rangle$ separates into two regimes with $M_a$. For $M_a \lesssim 1$, $\langle \theta \rangle$ rises rapidly with weak dependence on the background window, consistent with expansion-driven amplification of Alfvénic fluctuations. For $M_a \gtrsim 1$, the
evolution becomes scale dependent: large-scale $\langle \theta \rangle$ continues to grow with $M_a$ at reduced rate, while small-scale growth saturates, consistent with turbulent decay and dissipation. Collectively, these results indicate that switchbacks need not originate only in the super-Alfvénic
solar wind. Instead, they are consistent with a formation pathway in which coronal fluctuations are amplified by large-scale expansion through the sub-Alfvénic regime, with subsequent propagation into the super-Alfvénic wind where turbulent decay modifies their scale-dependent properties.
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All authors Nikos Sioulas, Marco Velli, Chen Shi, Lorenzo Matteini, Trevor A. Bowen, Alfred Mallet, A. Larosa, Anna Tenerani, Timothy S. Horbury
Earth and Planetary Astrophysics
Observational imprints of tidal internal gravity wave dissipation in star-planet systems
Yaroslav A. Lazovik and Adrian J. Barker
Tidal interactions play a crucial role in the orbital
evolution of close-in
star-
planet systems. There are numerous manifestations of tides, including planetary orbital migration, breaking resonant chains,
tidal heating, orbital circularization,
spin-orbit
alignment, and
stellar and planetary
spin synchronization. In the present study, we focus on the dissipation of internal
gravity waves within
stars. We examine two mechanisms: wave breaking in
stars with radiative cores and
magnetic wave conversion in
stars with convective cores. Applying
tidal prescriptions modelling these processes, we demonstrate that the enhanced
stellar rotation of both TOI-2458 and GJ 504 can be explained by the previous engulfment of a hot Jupiter caused by
gravity wave damping. Furthermore, we show that the observed population of hot Jupiters can be divided into two distinct subsamples: those that are too young for
gravity wave dissipation and those where it is ongoing. These subsamples exhibit qualitatively different orbital period distributions: young systems have a uniform distribution, while older systems show a steep decline at short orbital periods. Using a population synthesis approach, we successfully reproduce the main features of the older hot Jupiter sample based on the distribution of the younger systems. According to our estimates, up to 13% of the main-sequence
stars within the mass range [0.7,1.5] $M_{\odot}$ that once hosted a hot Jupiter may have since engulfed it. Our results highlight the key role of internal
gravity wave dissipation in shaping the orbital architectures of hot Jupiter systems.
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Cosmology and Nongalactic Astrophysics
Constraining cosmological simulations with peculiar velocities: a forward-modeling approach
Aurélien Valade, Noam Libeskind, Daniel Pomarède et al. (+4 more)
Numerical simulations are a key tool to decipher the dynamics of gravitation. Yet, they fail to spatially reproduce the Universe we observe, limiting comparison between observations and simulations to a statistical level. This is highly problematic for rare, faint or well studied nearby objects that are observed in a single environment. The computational cost of recovering this environment in random simulations is prohibitive. We present Hamlet-PM, a method that enables the constraining of initial conditions for cosmological simulations so as to produce evolved numerical universes that can be directly compared to observations of the Local Universe: constrained simulations. Our method implements the field-level forward modeling of the early-time density field from sparse and noisy measurements of late-time peculiar velocities. The dynamics are integrated with a particle-mesh
gravity solver, thus probing the mildly non-linear regime. The code is applied to the Cosmicflows-4 compilation of peculiar velocities up to z < 0.05 (160 Mpc/h). The constrained ICs a re-simulated with a high precision N-body code. A series of one hundred dark-matter only cosmological constrained simulations with a resolution of 512^3 particles in a 500^3 [Mpc/h]3 box is presented. Special
attention is given to twelve prominent nearby
galaxy clusters, whose simulated counterparts are matched on criteria of mass and separation. We provide a mass estimate constrained by the dynamical environment for each cluster. Field-level forward modeling of the initial conditions produces highly constrained cosmological simulations. Currently, this method already overtakes in quality the pipeline in use in the peculiar-velocity community, although systematic biases still need to be addressed. Furthermore, improving the model is easy thanks to the inherent flexibility of the
Bayesian approach.
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All authors Aurélien Valade, Noam Libeskind, Daniel Pomarède, Richard Stiskalek, Yehuda Hoffman, Stefan Gottlöber, R. Brent Tully
Astrophysics of Galaxies
JWST imaging of the Pleiades: anisotropy of turbulence in the cold neutral medium
G. Vigoureux, N. Flagey, F. Boulanger et al. (+14 more)
Interstellar medium studies rely on magnetohydrodynamic (MHD)
turbulence as a framework for interpretation. In this context, the statistical characterization of interstellar observations is of
prime importance. We open a new perspective on diffuse interstellar matter by analyzing James Webb Space
Telescope (JWST) observations of the Pleiades nebula with NIRCam. These observations are remarkable in that they provide a microscope view at the cold neutral medium (CNM) with a spatial resolution of 0.2 mpc (40 au). A two-dimensional
Fourier analysis is used to characterize the structure of PAH emission in regions near and far from the Pleiades
star Merope. To produce maps of the interstellar emission,
stars and
galaxies are filtered out. The final step in the data cleaning involves subtracting a component, in
Fourier space, which we infer to be a residual of the near-infrared
cosmic background. The PAH emission power spectra are highly anisotropic. They are well fitted with a break-free power-law, suggesting that we do not observe a specific scale for energy dissipation. Power-law indices are -3.5 near Merope and -3 in the more distant field. The
magnetic field orientation, as derived from the Planck
dust polarization data, aligns with the PAH anisotropy. The power anisotropy is constant across scales. These findings are discussed in relation to interstellar
turbulence that may be driven by the Pleiades
stars. The JWST observations of the Pleiades offer a new viewpoint for comparing observations and theoretical models, as they examine physical scales at which
turbulence in the CNM is subsonic and decoupled from the thermal instability. The observations may indicate that the turbulent energy cascade in the CNM is anisotropic.
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All authors G. Vigoureux, N. Flagey, F. Boulanger, A. Noriega-Crespo, V. Guillet, A. J. Alvarez-Castro, N. deJesus-Rivera, E. Allys, J. M. Delouis, E. Falgarone, B. Godard, P. Guillard, F. Levrier, P. Lesaffre, A. Marcowith, M. A. Miville-Deschênes, G. Pineau des Forêts
Earth and Planetary Astrophysics
Probing Atmospheric Escape Through the Near-Infrared Helium Triplet
C. Farret Jentink, V. Bourrier and Y. Carteret
The most productive tracer of exoplanetary atmospheric escape is the measurement of excess absorption in the near-infrared metastable helium triplet during transits. Atmospheric escape of a close-in
planet's atmosphere plays a role in its evolutionary pathway, but to which extent remains unknown. It could explain demographic features like the radius valley and Neptunian desert. We will describe the development of instrumental, reduction, and modelling techniques to study exoplanetary atmospheric escape, focusing on the helium triplet. One such development is the NIGHT spectrograph, intended to provide the first survey of escaping atmospheres. NIGHT spectra will be processed with ANTARESS, a state-of-the-art workflow for reducing high-resolution spectral time-series of
exoplanet transits and computing transmission spectra in a robust and reproducible way. Transmission spectra contain the potential signature of the planetary atmosphere as well as distortions induced by the occultation of local regions of the
stellar surface along the transit chord. Transmission spectra cannot be corrected for those
stellar distortions without biasing the planetary signal. They must instead be directly interpreted using a numerical model like the EvE code, which generates realistic
stellar spectra that account for the system's 3D architecture, the
planet's atmospheric structure, and its local occultation of the
stellar disc. This global approach, from the measurement and computation of transmission spectra to their interpretation, will be a legacy of the NCCR
PlanetS, becoming the standard procedure to study high-resolution spectroscopy of planetary transits.
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Earth and Planetary Astrophysics
Architectures of Planetary Systems II: Trends with Host Star Mass and Metallicity
Alex R. Howe, Juliette C. Becker and Fred C. Adams
The current census of planetary systems displays a wide range of architectures. Extending earlier work, this paper investigates the correlation between our classification framework for these architectures and host
stellar properties. Specifically, we explore how planetary system properties depend on
stellar mass and
stellar metallicity. This work confirms previously detected trends that jovian
planets are less prevalent for low-mass and low-
metallicity stars. We also find new, but expected trends such as that the total mass in
planets increases with
stellar mass, and that observed planetary system masses show an upper limit that is roughly consistent with expectations from the stability of circumstellar disks. We tentatively identify potential unique trends in the host
stars of super-puffs and hot jupiters and a possible subdivision of the class of hot jupiter systems. In general, we find that system architectures are not overly dependent on host
star properties.
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Astrophysics of Galaxies
Broadband infrared spectroscopy of methanol isotopologues in pure, H2O-rich, and CO-rich ice analogues
Adam Vyjidak, Barbara Michela Giuliano, Pavol Jusko et al. (+5 more)
Deuterium fractionation is highly efficient during the early stages of
star formation, particularly in starless and prestellar cores where temperatures are low (<10 K) and molecular freeze-out onto
dust grains is significant. Methanol forms early in these environments following CO freeze-out via successive hydrogenation reactions on grain surfaces, while the production of deuterated methanol requires elevated gas-phase D/H ratios generated through dissociative recombination of deuterated H3+. Consequently, large abundances of deuterated methanol are observed toward young
stellar objects where prestellar ices have recently sublimated. Here, we present laboratory infrared spectra of methanol and its deuterated isotopologues in astrophysical ice analogues, complemented by anharmonic vibrational calculations used to guide band assignments. Experiments were performed at the CASICE laboratory using a Bruker Vertex 70v spectrometer coupled to a closed-cycle helium cryostat, with isotopologue ices deposited at 10 K under high-
vacuum conditions. Infrared transmission spectra were recorded over 6000-30 cm-1 (1.67-333 um) and compared with spectra of pure isotopologue ices. Distinctive mid-infrared band patterns are identified for each deuterated species. In particular, CH2DOH exhibits a characteristic doublet at 1293 and 1326 cm-1 (7.73 and 7.54 um), while CHD2OH shows a similar doublet at 1301 and 1329 cm-1 (7.69 and 7.52 um), both remaining largely invariant across all studied ice mixtures. These robust spectral signatures provide reliable tracers for identifying deuterated methanol in JWST observations and for constraining astrochemical gas-grain models of deuterium enrichment prior to
star and
planet formation.
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All authors Adam Vyjidak, Barbara Michela Giuliano, Pavol Jusko, Heidy M. Quitian-Lara, Felipe Fantuzzi, Giuseppe A. Baratta, Maria Elisabetta Palumbo, Paola Caselli
Solar and Stellar Astrophysics
The Tarantula massive binary monitoring VII. The nature of the eccentric O+BH binary candidate VFTS 812
K. Deshmukh, H. Sana, O. Verhamme et al. (+9 more)
Massive O-type
stars ($M\gtrsim15\,M_\odot$) with an X-ray quiet black hole (BH) companion represent a crucial stage in massive binary
evolution leading to binary BH mergers. The population of such binaries remains elusive, with $\lesssim5$ candidate or confirmed systems. The Tarantula nebula harbors thousands of massive
stars, 2-3 % of which are expected to have BH companions. It is therefore an ideal place to hunt for such systems. Here we analyse 30 epochs of VLT/FLAMES IFU high-resolution observations of the H$\delta$ region, as well as archival FLAMES spectroscopy, of VFTS 812, a 17-day single-lined spectroscopic binary with an O4V primary and a minimum secondary mass of $5.1\,M_\odot$. Following careful removal of the nebular contamination, spectral disentangling on the new data did not reveal any signature of the hidden companion. We derive $T_\mathrm{eff}=49^{+3}_{-4}$ kK, $\log L/L_\odot=5.7\pm0.1$ and $v_\mathrm{rot,max}{\rm \,sin\,}i=110^{+25}_{-35}$ km/s for the O4V component, yielding a (single
star) evolutionary mass of $53^{+6}_{-5}$ $M_\odot$ and an age in the range of 0-1.6 Myr. Using injection tests of various luminous artificial companions in our data, we exhaustively rule out the presence of any luminous signature from a main sequence
star more massive than $6\,M_\odot$. We discuss the possible nature of the companion, suggesting that the rejuvenated O
star + BH companion is the most suitable scenario to consistently explain the location, (rejuvenated) young age, eccentricity and lack of companion signature. While this establishes VFTS 812 as a strong candidate O+BH system, follow-up observations are deemed necessary for robust confirmation and to search for
accretion signatures on the O4V
star.
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All authors K. Deshmukh, H. Sana, O. Verhamme, R. Willcox, P. Marchant, T. Shenar, F. Backs, S. Janssens, B. Ludwig, L. Mahy, J. O. Sundqvist, J. I. Villaseñor
Solar and Stellar Astrophysics
Light-Curve and Spectral Properties of Type II Supernovae from the ATLAS survey
K. Ertini, J. P. Anderson, G. Folatelli et al. (+22 more)
Type II
supernovae (SNe II) are the most common terminal
stellar explosions in the Universe. With SNe now being detected within days after explosion, there is growing evidence that the majority of Type II SNe show signs of interaction with a confined, dense cirumstellar material (CSM) in the first few days post explosion. In this work we aim to bridge the gap between single SN studies showing early-time interaction in their spectra, and the statistical studies of early-time SN light curves, which imply the existence of CSM. We present a sample of 68 Type II SNe with both early photometric data, obtained with the ATLAS survey, and spectroscopic data, obtained with the ePESSTO+ collaboration. A subset of the sample is classified based on the presence or absence of narrow spectral features with electron-scattered broadened wings in the early spectra, indicative of interaction with CSM. We characterise the photometric and spectroscopic properties of the sample by measuring rise times to maximum light, peak magnitudes, decline rates and line velocities. Additionally, we measure the ratio of absorption to emission (a/e) of the H alpha P-Cygni profile. Our analysis reveals that SNe II showing early spectroscopic signs of interaction with CSM decline faster and are brighter than those without. However no difference is found in rise times between the two groups. A clear separation is observed in the a/e ratio: SNe with signs of interaction exhibit lower a/e ratios at all epochs compared to those without. Our results highlight that understanding SN II ejecta-CSM interaction requires large, uniform samples of photometric and spectroscopic data, such as the one presented in this work.
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All authors K. Ertini, J. P. Anderson, G. Folatelli, S. González-Gaitán, C. P. Gutiérrez, J. Sollerman, O. Rodríguez, A. Aryan, T.-W. Chen, E. Concepcion, S.P. Cosentino, M. Dennefeld, N. Erasmus, M. Fraser, L. Galbany, M. Gromadzki, C. Inserra, T. E. Müller-Bravo, P. J. Pessi, T. Pessi, T. Petrushevska, G. Pignata, F. Ragosta, S. Srivastav, D. R. Young
High Energy Astrophysical Phenomena
A case for Case A: detailed look at binary black hole formation through stable mass transfer
Max M. Briel, Tassos Fragos, Monica Gallegos-Garcia et al. (+8 more)
In isolated binary
evolution, binary black hole (BBH) mergers are generally formed through stable mass transfer (SMT) or common envelope
evolution. In recent years, the SMT channel has received significant
attention due to detailed binary models showing increased mass transfer stability compared to previous studies. In this work, we perform a full zero-age-main-sequence to compact object merger analysis using detailed binary models at eight
metallicities between $10^{-4}Z_\odot$ and $2Z_\odot$ to self-consistently model the population properties of BBH mergers in the SMT channel, determined their progenitor initial conditional, and investigate the binary physics governing their formation and
metallicity dependence. We use the population synthesis code POSYDON to determine the population of BBH mergers from SMT. Using its extended grids of MESA binary models, we determine the essential physics in the formation of BBH mergers. SMT produces BBH mergers predominantly from systems with $P_{ZAMS}\leq10$ days. In these systems, both the initial mass transfer between two
stars and the subsequent interaction between the remaining
star and the first-born BH take place while the respective donor
star is on the main-sequence (Case A). We find a limited contribution from wider Case B/C systems. Without a natal kick, the SMT channel does not produce BBH mergers above $Z>0.2Z_\odot$ due to orbital widening from
stellar wind mass loss. The primary BH mass distribution shows a strong dependence on
metallicity, while the mass ratio prefers unity independent of
metallicity due to mass ratio reversal. Additionally, the $\chi_{eff}$ distributions contain peaks at $\chi_{eff}=0$ and ~0.15 of which the former disappears at high
metallicities. A mass-scaled natal kick leave this sub-population unchanged but introduce a low-mass, unequal mass ratio sub-population that merges due to their high eccentricity.
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All authors Max M. Briel, Tassos Fragos, Monica Gallegos-Garcia, Anarya Ray, Michael Zevin, Abhishek Chattaraj, Jeff J. Andrews, Vicky Kalogera, Seth Gossage, Philipp M. Srivastava, Elizabeth Teng
Instrumentation and Methods for Astrophysics
A Method for Thermal Radiation Transport Using Backward Characteristic Tracing
J. C. Dolence, H. R. Hammer, H. Park et al. (+3 more)
Thermal radiation transport is a challenging problem in computational physics that has long been approached primarily in one of a few standard ways: approximate moment methods (for instance P$_1$ or M$_1$), implicit Monte Carlo, discrete ordinates, and long characteristics. In this work we consider the efficacy of the Method of (Long) Characteristics (MOC) applied to thermal radiation transport. Along the way we develop three major ideas: transporting MOC particles backwards in time from quadrature grids at the end of the timestep, limiting the computational cost of these backward characteristics by terminating transport once optical depths along rays become sufficiently large, and timestep-dependent closures with multigroup MOC solutions for a gray low-order system. We apply this method to a suite of standard radiation transport and radiation hydrodynamics test problems. We compare the method to several standard analytic and semi-analytic solutions, as well as implicit Monte Carlo, P$_1$, and discrete ordinates (S$_n$). We see that the method: gives excellent agreement with known results, has stability for large time steps, has the
diffusion limit for large spatial
cells, and achieves $\sim$20-70% performance improvement when terminating optical depths at O(10-100) in the grey Marshak and crooked pipe problems. However, for the Coax radiation-hydrodynamics problem, we see that MOC is approximately two to three times slower than IMC-DDMC and S$_n$ in its current implementation.
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All authors J. C. Dolence, H. R. Hammer, H. Park, B. Prather, B. R. Ryan, R. T. Wollaeger
Earth and Planetary Astrophysics
On the Influence of Pluto on Twotino Dynamics Through Their Mutual 4:3 Mean Motion Resonance
S. Ramírez-Vargas, A. Peimbert, M. A. Muñoz-Gutiérrez et al. (+1 more)
Context: The role of Pluto contributing to the long-term
evolution of the trans-Neptunian region has been considered significant only over its neighboring Plutinos. However, it has recently been found that the long-term stability of the Twotino population is strongly affected when including Pluto as a massive object in simulations, while Eris, with a similar mass, has a negligible effect. Aims: We hypothesize that the effect of Pluto on Twotinos results from the latter being trapped in a 4:3 mean motion resonance (MMR) with Pluto. In this work, we aim to demonstrate the resonant behavior of Twotinos within Pluto's 4:3 MMR and the significance of this resonance for the long-term
evolution of the population. Methods: We run high-resolution, 10 Myr REBOUND simulations of the observed Twotino population in the Kuiper belt, under the perturbations of the Sun, the four
giant planets, and Pluto, as massive objects. Results: We find that all objects trapped in the 2:1 MMR with Neptune are locked in a weak 4:3 MMR with Pluto. The 4:3 resonant angles of most objects trapped in the leading and trailing islands of the 2:1 MMR, librate with amplitudes lower than $360^\circ$. Objects in the symmetric islands of the 2:1 MMR librate in the 4:3 MMR with amplitudes greater than $360^\circ$, but, contrary to circulating objects, will oscillate by up to $840^\circ$ visiting preferred angles on Pluto's co-rotating frame, indicating a diluted resonant effect that may also perturb their orbits on secular timescales. Conclusions: The importance of Pluto in shaping the structure of the trans-Neptunian region should be reconsidered, specifically for resonant populations. Moreover, with current computational power, its exclusion from simulations can not be justified.
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All authors S. Ramírez-Vargas, A. Peimbert, M. A. Muñoz-Gutiérrez, A. Perez-Villegas
Astrophysics of Galaxies
Narrow absorption lines from intervening material in supernovae: III. Supernovae and their environments
Claudia P. Gutiérrez, Santiago González-Gaitán, Joseph P. Anderson et al. (+1 more)
Narrow interstellar absorption features in
supernova (SN) spectra serve as valuable diagnostics for probing
dust extinction and the presence of circumstellar or interstellar material. In this third paper in a series, we investigate how the strength of narrow interstellar absorption lines in low-resolution spectra varies with SN type and host
galaxy properties, both on local and global scales. Using a
dataset of over 10000 spectra from $\sim1800$ low-
redshift SNe, we find that Type Ia SNe (SNe Ia) in passive
galaxies exhibit significantly weaker narrow absorption features compared to CC-SNe and SNe Ia in
star-forming hosts (SNe Ia-SF), suggesting lower interstellar gas content in quiescent environments. Within the
star-forming hosts, the Na I D equivalent-width distribution of SNe II is much lower than that of both SNe Ia-SF and stripped-envelope SNe (SE-SNe). This result is somewhat unexpected, since CC-SNe are generally associated with
star-forming regions and occur deeper within
galactic disks, where stronger line-of-sight extinction would be anticipated. This suggests that the observed behaviour cannot be explained solely by absorption from the integrated interstellar medium (ISM) along the line of sight. Instead, if part of the absorption arises from material near the explosion, the similarity between the Na I D EW distributions of SNe Ia-SF and SE-SNe implies that comparable absorption signatures can emerge from distinct progenitor pathways. Possible explanations include (a) circumstellar material (CSM) expelled by the progenitor system before explosion, or (b) interaction of SN radiation with nearby patchy ISM clouds. Our results highlight the diagnostic power of interstellar absorption features in revealing the diverse environments and progenitor pathways of SNe.
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All authors Claudia P. Gutiérrez, Santiago González-Gaitán, Joseph P. Anderson, Lluís Galbany