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Physics Astrophysics

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Monday 20 April

Cosmology and Nongalactic Astrophysics

If at First You Don't Succeed, Trispectrum: I. Estimating the Matter Power Spectrum Covariance with Higher-Order Statistics

We present a method to estimate non-Gaussian power spectrum covariance matrices by directly measuring the response of the small-scale power spectrum to long-wavelength perturbations via bispectrum and trispectrum estimators. Specifically, we derive estimators for the complete non-Gaussian matter power spectrum covariance, including the super-sample contribution, in terms of the squeezed bispectrum and collapsed trispectrum of the underlying density field. We apply these estimators to the Quijote simulations, and recover unbiased estimates of the small-scale ($k\gtrsim 0.15~h/{\rm Mpc}$) matter power spectrum covariance at the percent level using only 25 simulations - comparable to the precision of the sample covariance estimated using 5,000 simulations. This technique significantly reduces the number of simulations needed to estimate power spectrum covariances and opens the possibility of inferring power spectrum covariances directly from survey data, enabling stringent tests of simulations and, potentially, power spectrum analyses that do not rely on external covariance matrices.
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All authors Samuel Goldstein, Kendrick M. Smith, Utkarsh Giri, Moritz Münchmeyer

Earth and Planetary Astrophysics

The T16 Planet Hunt: 10,000 New Planet Candidates from TESS Cycle 1 and the Confirmation of a Hot Jupiter Around TIC 183374187

The T16 project has produced a uniformly detrended and systematics-corrected set of 83,717,159 TESS Cycle 1 full-frame image light curves for stars observed by TESS in its primary mission down to T=16 mag, enabling sensitive transit searches beyond the official TESS pipelines. While most existing TESS planet searches focus on relatively bright targets, planet occurrence rates suggest that a substantial number of planets should exist around fainter stars. We therefore use the T16 light curves to conduct a semi-automated search for transiting exoplanets across the full Cycle 1 FFI sample, resulting in 11,554 planet candidates orbiting stars down to 16th magnitude in the TESS band with orbital periods between 0.5 and 27 days. Of these, 10,091 are new planet candidates, and 411 are single-transit events, for which we do not attempt to determine orbital parameters. The remaining 1,052 candidates are previously known TESS candidates. We validate our pipeline through Magellan/PFS radial-velocity follow-up measurements on one of our candidate hosts, TIC 183374187, a metal poor thick-disk star, confirming the signal as newly identified hot Jupiter. This detection demonstrates our pipeline's ability to identify real, previously undiscovered, transiting planets. Overall, this work shows that large-scale, machine learning-assisted transit searches of TESS full-frame images can significantly expand the census of transiting planet candidates, particularly around faint stars, providing a rich target set for future validation and follow-up efforts. Our findings more than double the number of known TESS exoplanet candidates.
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All authors Joshua T. Roth, Joel D. Hartman, Gáspár Á. Bakos, Samuel W. Yee, Luke G. Bouma, Jhon Yana Galarza, Johanna K. Teske, R.P. Butler, Jeffrey D. Crane, Steve Shectman, David Osip, Shreyas Vissapragada, Yuri Beletsky, Shubham Kanodia, Yadira Gaibor

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

On the curlometer measurement of field-aligned and perpendicular currents in low Earth orbit: Swarm observations and whole geospace simulations

Measuring field-aligned currents (FACs) using magnetic field observations provides a powerful means to probe the multi-scale interactions between the magnetosphere, ionosphere and thermosphere. In this study, we benchmark the curlometer technique using Swarm spacecraft observations and simulations of the coupled magnetosphere-ionosphere system. We begin by correlating current density curlometer estimates derived from Swarm tetrahedra with varying spatial scales and barycentre locations. This confirms an apparent departure from stationarity for FACs at spatio-temporal scales below 100 km where measurements appear highly uncorrelated. We then analyse simulated magnetic perturbations, where four-point measurements can always be constructed. This shows how, even at meso-scales of hundreds of kilometres, time-shifted FAC estimates can diverge significantly from this ground truth. In both observational and simulated data we find poor tetrahedral configurations can produce spurious perpendicular currents due to numerical instability in the inversion process. This can be mitigated using appropriate quality metrics and high-quality FAC reconstructions still achieved with a tetrahedral face well-aligned to the local magnetic field. These results highlight the dynamic nature of FACs at large as well as small scales, and underscore the substantial advantages of true four-point observations for their accurate analysis.
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All authors R Gajewski, RT Desai, B Hnat, D Lin, MW Dunlop, M Fillion, G Hulot, Shreedevi P R, M-T Walach, E Panov, J-M Leger, T Jager, D Fischer, W Magnes, JA Blake, T Etchells

Astrophysics of Galaxies

A Census of Na D-traced neutral ISM and outflows at $0.6<z<4$

We present a statistical census of the Na D-traced neutral interstellar medium (ISM) and outflows in 309 galaxies at $0.6<z<4$ using JWST/NIRSpec medium-resolution spectroscopy from the SMILES, JADES, Blue Jay, and Aurora surveys. After subtracting the stellar continuum, we model the Na D $\lambda\lambda 5890, 5896$ Åand identify 73 Na D ISM absorptions, including 63 robust (4 in broad-line AGNs) and 10 tentative detections. Of the robust detections, 88% are found in massive galaxies ($\log(M_*/M_\odot)>10$), and 12% in lower-mass systems. At high mass, ISM absorption is seen in both star-forming and quiescent galaxies, whereas in lower-mass systems it is observed only in star-forming galaxies. In massive quiescent galaxies, Na D detectability appears linked to star formation history: it is preferentially detected in older systems with larger 4000 Åbreaks, and younger, rapidly quenching galaxies with strong Balmer absorption H$\delta_A$. We identify Na D outflows in 25 galaxies, revealing a possible dichotomy in driving mechanisms between star-forming and quiescent galaxies. In star-forming galaxies, outflow properties correlate with star-formation properties, consistent with a star-formation-driven origin. In quiescent galaxies, however, outflows are not associated with residual star formation and often require more energy than such star formation can provide. Together with the high AGN fraction among outflow-detected quiescent galaxies, this suggests that AGN dominate Na D-traced neutral outflows in cosmic noon quiescent systems. We further identify four quiescent galaxies with possible AGN fossil outflows, suggesting that AGN-driven outflows can persist beyond the active accretion phase and may help maintain quiescence.
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All authors Yang Sun, Zhiyuan Ji, Francesco D'Eugenio, Yongda Zhu, George H. Rieke, William M. Baker, Andrew J. Bunker, Stefano Carniani, Jakob M. Helton, Michele Perna, Pablo G. Pérez-González, Pierluigi Rinaldi, Hannah Übler, Christopher N. A. Willmer

Astrophysics of Galaxies

NOEMA3D: Extended CO, [C I] and dust in massive star-forming main-sequence galaxies at cosmic noon

We present a spatially resolved study of cold molecular gas and dust in ten main-sequence galaxies at z=1.1-1.6, using observations of CO(4-3), CO(3-2), [CI](1-0), and dust continuum from the NOEMA3D survey. We find widespread spatially extended molecular gas and dust, with sizes comparable to those of the stellar disk, in contrast to those of centrally dominated starburst galaxies at similar redshifts. Among the targeted molecular gas tracers, the CO line (J=3-2 or J=4-3) remains the most effective for mapping molecular gas distribution and kinematics. The spatially resolved correlations between different molecular gas tracers exhibit about twice the scatter as their galactic-integrated correlations, indicating that interstellar medium (ISM) conditions already deviate from global averages on scales of 3-6 kpc. This likely reflects the clumpy or inhomogeneous ISM in cosmic noon star-forming galaxies. Within our sample, both the molecular gas fraction and its depletion time are nearly constant across the galactic disks out to 2xRe, supporting a global linear Kennicutt-Schmidt law. These galaxies also have relatively small bulges, with bulge-to-total ratios between 6-24%, and are actively forming stars. These results provide a resolved view of how galaxies can remain on the star-forming main sequence during their secular evolution at late cosmic noon, an evolutionary stage supported by quasi-steady gas accretion and efficient gas transport via prominent spiral arms and/or bars.
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All authors Jianhang Chen, Linda J. Tacconi, Reinhard Genzel, Roberto Neri, Karl Schuster, Natascha M. Förster Schreiber, Jean-Baptiste Jolly, Stavros Pastras, Letizia Scaloni, Giulia Tozzi, Capucine Barféty, Alberto Bolatto, Andreas Burker, Françoise Combes, Pierre Cox, Ric Davies, Frank Eisenhauer, Juan Manuel Espejo Salcedo, Rodrigo Herrera-Camu, Santi García-Burillo, Tadayuki Kodama, Lilian Lee, Minju M. Lee, Daizhong Liu, Dieter Lutz, Giovanni Mazzolari, Thorsten Naab, Amit Nestor Shachar, Claudia Pulsoni, Alvio Renzini, Monica Rubio, Taro T. Shimizu, Amiel Sternberg, Eckhard Sturm, Hannah Übler, Antonio Usero, Stijn Wuyts

Astrophysics of Galaxies

NOEMA3D: Resolving radial gas flows in disk galaxies at z~1.1-1.6 with high-resolution CO observations

We present NOEMA3D, a unique high-resolution study of purely molecular gas kinematics at $z \sim 1.1$ to 1.6, providing a dedicated view of cold gas dynamics at the late stages of the peak epoch of cosmic star formation. Using deep ($> 20$ hr on source per target) IRAM-NOEMA CO observations of 10 massive ($10.45 < \log(M^*/M_\odot) < 11.43$)) main-sequence galaxies, complemented by high-resolution JWST imaging, we resolve the molecular gas kinematics and morphology on kiloparsec scales. We find that all galaxies exhibit ordered rotation with moderate intrinsic turbulence (median $\sigma_0 \sim 32 \pm 10$ km/s, median $V_c/\sigma_0 \sim 8.6 \pm 2.9$), consistent with dynamically turbulent disks at late cosmic noon. After modeling the axisymmetric rotation with the forward-modeling code DysmalPy, we reveal spatially coherent velocity residuals in all but one more inclined system. The inferred in-plane non circular motions reach amplitudes of $\sim 50$-100 km/s, significantly larger than typically observed in local disk galaxies. Interpreting these non-circular motions as radial flows we find that the velocity residuals spatially coincide with non-axisymmetric structures – spiral arms and bars – demonstrating a direct link between galaxy morphology and gas transport at $z \sim 1$-2. In spiral galaxies, the residual velocity patterns are typically dominated by inflows, while barred systems display an apparent inflow-outflow pattern, characteristic of in-plane bar-driven gas motions. We further find that the inferred molecular gas inflow rates are substantial, with a typical net inflow rate of the order of the star formation rate ($\dot M \sim -50 M_\odot$/yr). This implies that spiral arms and bars at cosmic noon are highly efficient at funneling cold gas toward galaxy centers, perhaps driving the buildup of bulges and feeding central star forming regions and supermassive black holes.
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All authors Jean-Baptiste Jolly, Linda J. Tacconi, Reinhard Genzel, Roberto Neri, Karl Schuster, Jianhang Chen, Natascha M. Förster Schreiber, Stavros Pastras, Letizia Scaloni, Giulia Tozzi, Capucine Barféty, Alberto Bolatto, Andreas Burker, Françoise Combes, Pierre Cox, Ric Davies, Frank Eisenhauer, Juan Manuel Espejo Salcedo, Rodrigo Herrera-Camu, Santi García-Burillo, Tadayuki Kodama, Lilian Lee, Minju M. Lee, Daizhong Liu, Dieter Lutz, Giovanni Mazzolari, Thorsten Naab, Amit Nestor Shachar, Claudia Pulsoni, Alvio Renzini, Monica Rubio, Taro T. Shimizu, Amiel Sternberg, Eckhard Sturm, Hannah Übler, Antonio Usero, Stijn Wuyts

Solar and Stellar Astrophysics

Active-region Modulation of Subsurface Meridional Flows and Magnetic Flux Transport on the Sun

Using time-distance helioseismology applied to 14-years of SDO/HMI observations spanning solar cycle 24 and rising phase of cycle 25, we present evidence that meridional flows in the lower half of the near-surface shear layer (NSSL), modulated by active-region magnetic fields, play a central role in the episodic global transport of magnetic flux. In particular, polar field buildup is tightly linked to plasma outflows diverging from active latitudes within the deeper NSSL. The magnitude and timing of hemispheric polar field evolution are regulated by depth-dependent meridional flow, including its cross-equatorial component, responding to active-region flux asymmetries. During cycle 24 maximum, stronger southern outflows accelerated flux transport, causing the southern polar field to peak nearly four years before the northern. Global magnetic flux transport patterns in the previous three solar cycles (21, 22, and 23) show broad consistency with the deeper meridional flow modulation inferred in cycles 24 and 25. These results identify activity-dependent flow variations in deeper layers of the NSSL as a dynamically significant component of the Babcock-Leighton process that governs the generation and hemispheric asymmetry of global dipole field.
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All authors Anisha Sen, S.P. Rajaguru, Ruizhu Chen, Junwei Zhao, Shukur Kholikov

Earth and Planetary Astrophysics

Correcting radar meteor fluxes for observing biases

We report on an eight year survey of simultaneous optical and radar meteor detections with the goal of isolating the fraction of meteors missed by specular radars. A total of 10,503 Electron Multiplied Charge Couple Device (EMCCD) meteors with peak brightness above +7 were simultaneously detected by the Canadian Meteor Orbit Radar (CMOR) and used to estimate the fraction of radar echoes missed as a function of speed and height. During the time period that our cameras were recording, we found some 34,119 and 18,008 meteor echoes in total occurred within the field of view of the EMCCD cameras at 29 and 38 MHz respectively. This demonstrated that a significant fraction of the specular radar echoes remain below the detection threshold of the EMCCD cameras. We used these data to derive corrections for radar-specific observing biases. The optical height distributions for six velocity bins, spanning 10 - 72 km/s were used to determine the fraction of potential radar echoes which are observed for meteors with higher begin heights ($k_c$>96) and for those with lower begin heights. When compared to the correction factors currently used in calculating shower fluxes with CMOR, mid-velocity showers such as the Geminids and South Delta Aquariids are found to have been overcorrected, while high velocity showers like the Perseids and Leonids are significantly undercorrected.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-th

Classical and quantum evolution of inflationary fluctuations

We compare the correlation functions of inflationary perturbations computed either with quantum or classical dynamics. Even if they are enforced to agree at a specific time during inflation, classical and quantum correlations will differ at the end of inflation, provided that interactions are relevant. The difference between the results of the classical and quantum computations is exponentially sensitive to the number of e-folds elapsed from the time of agreement. We illustrate this finding with the tree-level bispectrum of the primordial curvature fluctuation and the one-loop power spectrum of tensor modes. We also show that classical evolution from a finite time does not imply the appearance of poles in the scalar bispectrum.
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High Energy Astrophysical Phenomena · Cross-listed from hep-ph

Looking for Lights from the Darkness: Signals from MeV-scale Solar Axion-like Particles

The axion-like particles $a$ can be produced in the Sun via the process of $p + D \to {}^3{\rm He} +a$, with mass up to 5.5 MeV. The photons in the subsequent decay $a \to \gamma\gamma$ can deviate significantly from the Sun, or even from roughly the opposite direction of the Sun. The nontrivial angular and spectral distributions of such photons enable us new methods to detect the lights from the darkness. In this letter, we consider both the space detection and terrestrial experiments at the South Pole. As a result of the two-body decay and the geometric effects, there exists a critical height for the terrestrial experiments, below which there is no photon for some regions of the parameter space. With the sensitivities of $10^{-16}$ ($10^{-17}$) erg cm$^{-2}$ s$^{-1}$ for the MeV-scale photons in future space and terrestrial experiments, the coupling $g_{a\gamma}$ of $a$ to photons can be probed up to $3\times10^{-12}$ ($1\times10^{-12}$) GeV$^{-1}$, well surpassing the current supernova limits.
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Astrophysics of Galaxies

Molecular Clouds at the Edge of the Galaxy II. Physical properties and scaling relations

The outer Galaxy presents an optimal setting for investigating molecular clouds and star formation in environments with low metallicity. A total of 72 Galactic edge clouds were surveyed using the CO\,(2–1) line with the IRAM\,30\,m telescope, leading to the identification of 112 CO clumps within molecular clouds with linear resolutions of 0.5–0.9\,pc. Parameters such as size, mass, surface density, and velocity dispersion of these CO clumps, derived from CO\,(2–1) observations, exhibit ranges of 0.6–3.4\,pc, 34–8250\,M$_\odot$, 12–1025\,M$_{\odot}$\,pc$^{-2}$, and 0.3–1.7\,km\,s$^{-1}$, respectively. Over the Galactocentric distance range of 14–23\,kpc, no systematic variations are found in these parameters. The velocity dispersion-size relationship of the Galactic edge clumps is modeled as $\sigma_{\rm v}$\,=\,0.69($\pm$0.03)$R_{\rm eff}^{0.36(\pm0.10)}$, indicating that turbulence is present within the Galactic edge clumps, akin to observations in the inner Galactic disk clouds. Furthermore, the luminous mass-size relation of the Galactic edge clumps is described by $M_{\rm lum}$\,=\,196($\pm$17)$R_{\rm eff}^{\,2.18\,(\pm0.26)}$, suggesting the average column density remains almost constant for clouds of different sizes. The virial parameters range from 0.6 to 15.3, with a median value of 2.8\,$\pm$\,0.6, suggesting that most clumps are gravitationally unbound. Furthermore, the virial parameters of our Galactic edge clumps show a decreasing trend with increasing Galactocentric distances, described by an exponential relation $\alpha_{\rm vir}$\,=\,33.0($\pm$\,10.4)\,e$^{-R_{\rm g}/6.7(\pm0.9)}$, consistent with previous results.
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All authors C. S. Luo, X. D. Tang, C. Henkel, Y. Sun, Y. Gong, X. W. Zheng, T. Liu, X. Lu, Y. P. Ao, X. P. Chen, D. L. Li, Y. X. He, K. Wang, J. W. Wu, J. Esimbek, J. J. Zhou, G. Wu, Y. X. Ma, W. A. Baan, J. J. Qiu, X. Zhao, J. S. Li, Q. Zhao, L. D. Liu, C. Y. Wang

Cosmology and Nongalactic Astrophysics

Fourth-order galaxy-galaxy-lensing: Theoretical framework and direct estimation

Traditional galaxy-galaxy lensing is a well-established method of probing the statistical properties of the Universe's matter and galaxy distribution. However, this measure does not carry all the statistical information, provided the matter and galaxy distribution contain non-Gaussian features. In order to study these non-Gaussianities, it is necessary to consider higher-order statistical measures. The aim of this work is to extend the analytical basis describing the statistical correlations between galaxies and shear to the fourth order, with special emphasis on the associated aperture statistics. In order to include fourth-order statistics in future analysis of the relation between mass and galaxies, we further investigate whether we can expect to detect these statistics from observations of stage IV surveys. We define the four-point correlation function (4PCF) between the shear and the positions of triplets of foreground galaxies and derive its relation to the respective trispectrum. We convert the 4PCF to aperture statistics and derive the analytical form of the respective filter function, which we then implement in a numerical integration pipeline. Furthermore, we develop a direct estimator that allows us to measure galaxy-mass aperture moments of arbitrary order on pixelized data using a Fast-Fourier-Transform (FFT) algorithm. We show that the corresponding aperture measure $\langle\mathcal{N}^3 M_\mathrm{ap}\rangle$ can be calculated with sub-percent accuracy on relevant aperture scales, $\theta$, by means of numerical integration. Furthermore, we apply the FFT-based direct estimator to a mock catalog with a realistic stage IV survey setup on a sky area of $2000~\mathrm{deg}^2$, and detect the connected part of the aperture statistics $\langle\mathcal{N}^3 M_\mathrm{ap}\rangle(\theta)$ with a signal-to-noise ratio of roughly nine on small aperture scales.
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All authors Jonathan Oel, Lucas Porth, Peter Schneider, Elena Silvestre-Rosello

Solar and Stellar Astrophysics

Spectroscopic survey of faint planetary-nebula nuclei. VII. Thirty new hydrogen-deficient central stars

Our ongoing spectroscopic survey of faint planetary-nebula nuclei (PNNi) has revealed 30 new hydrogen-deficient central stars. The majority of them (21) belong to the PG1159 spectral class (having He-C-O-dominated atmospheres). They increase the number of known PN central stars of this type from 25 to 46. Our spectral analysis finds that their effective temperatures are high (T$_{\rm eff}$ = 110,000 - 180,000 K), locating them in the GW Vir pulsational instability strip. Future photometric observations should therefore substantially increase the number of known PNN pulsators (currently, it is nine). We found six new members of the O(He) spectral type (with He-dominated atmospheres; T$_{\rm eff}$ = 120,000 - 150,000 K), tripling the number of known PNNi of this class. Finally, we identified three hot helium-rich white dwarfs with traces of carbon and/or nitrogen (spectral type DOZ; T$_{\rm eff}$ = 70,000 - 100,000 K). They are the first objects of this spectral class found to be associated with a planetary nebula.
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High Energy Astrophysical Phenomena

Probing the 3D Structures of Supernovae through IR Signatures of CO and SiO

We present a new public-domain MOlecular Fitting Analysis Tool (MOFAT) designed to probe molecule-forming regions in supernovae (SNe) through analysis of molecular features in the near- and mid-infrared. MOFAT employs a novel data-driven approach to explore the physical properties of these regions using time-independent radiative transfer simulations that include multidimensional, clump-like structures, constrained by high-precision observations. Such structures are required to reproduce the flux ratio between fundamental and overtone bands, overcoming limitations of traditional one-zone forward-modeling, such as optical-depth effects and initial configurations. Our approach enables spectral fits that can reconstruct overall abundances and temperatures and determine parameterized small-scale structures associated with physical instabilities. We systematically study the relationship between physical parameters and the profiles of CO and SiO, showing that free parameters are constrained, while detection of small-scale structure requires optically thick bands. As a demonstration, MOFAT is applied to SN2024ggi at +285 and +385 days post-explosion. We find that CO formation triggers SiO formation in the inner layers of the CO-rich region previously studied. The inner edge of the SiO-emitting region recedes from velocities of v1 from 1500 to 1000 km/s, indicating continued SiO formation. The SiO mass decreases from about (2-6)E-3 Mo by roughly an order of magnitude, suggesting ongoing evaporation. SiO features indicate clumping, but most of the flux originates from optically thin regions. SiO contributes negligibly to cooling, and we find no evidence for dust formation. Finally, we discuss observational strategies to trace the evolution of molecule formation and its connection to dust formation.
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All authors T. Mera, P. Hoeflich, C. R. Burns, C. Ashall, K. Medler, E. Fereidouni, W. B. Hoogendam, M. Shahbandeh, S. Shiber, C. M. Pfeffer, E. Baron, J. Lu, N. Morrell, E. Y. Hsiao, M. M. Phillips

Cosmology and Nongalactic Astrophysics

The MeerKAT Fornax Survey VII. Characterisation of the Fornax cluster's magnetic field and new insights on magnetisation in large scale systems

Large scale magnetic fields in galaxy clusters can influence their physics and the evolution of the cluster galaxies. These properties remain poorly constrained due to a historical lack of high-sensitivity and high-resolution spectro-polarimetric data. Thanks to the advent of the SKA pathfinders and precursors this is now dramatically changing. By exploiting the densest RM grid produced to date with broadband spectro-polarimetric data in the context of the MeerKAT Fornax Survey and presented in a previous paper (508 sources over 6.35 deg$^2$), we aim to study in detail the Fornax cluster's magnetic field. We compare the RM grid properties with numerical simulations to constrain the strength and the structure of the intra-cluster magnetic field. We model the magnetic field power spectrum with a power-law and we find a slope of $\sim$2.7 fluctuating between $\sim$1 and $\sim$15 kpc. It has a central strength of $\sim$5$\mu$G decreasing with the thermal plasma density according to a power-law exponent of $\sim$1.6, the highest value to date in large scale systems. By analysing a sample of 17 galaxy clusters and groups with magnetic field estimates from the literature, we observe larger auto-correlation lengths in the case of massive merging clusters and lower values for relaxed clusters and low-mass systems. We also observe a systematic increase of the central magnetic field strength as a function of central density, $B_0\propto n_0^{0.38}$. Finally, we argue that the steepening of the Fornax cluster's magnetic field profile and its relatively high central strength could be indicative of a recent re-amplification at the centre due to the extended central radio galaxy. The sample analysis supports the proposed scenario, although more detailed magnetic field studies conducted using consistent modelling on larger samples are needed to better understand magnetisation in clusters and groups.
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All authors Francesca Loi, Matteo Murgia, Federica Govoni, Paolo Serra, Valentina Vacca, Filippo Marcello Maccagni, Peter Kamphuis, Dane Kleiner

Earth and Planetary Astrophysics

Dust characterization of halos: The extended emission in protoplanetary disks

Extended low surface brightness emission has been identified in a number of protoplanetary disks, in tension with predictions of radial drift theory. We aim to investigate the nature and origin of faint, extended dust emission in the outer regions of protoplanetary disks, which we define as the "Halo", using multiwavelength (sub)millimeter continuum observations of three systems: Elias 2-24, IM Lup, and DM Tau. We utilized Atacama Large Millimeter Array (ALMA) observations of our targets to perform spectral energy distribution (SED) fitting with four dust compositions and derived radial profiles of their dust properties. The halos identified in our sources account for 20 - 30% of the total flux density at (sub)millimeter wavelengths. In Elias 2-24, IM Lup, and DM Tau, we infer maximum grain sizes of 2 cm, $<$ 4 mm, and $<$ 9 mm, with the data best reproduced by porous amorphous carbon, compact amorphous carbon, and compact organic carbon compositions, respectively. Their total dust masses are $125^{+34}_{-23}$, $301^{+139}_{-101}$, and $829^{+761}_{-378}$ M$_{\oplus}$, with corresponding halo masses of $33^{+12}_{-6}$, $103^{+25}_{-17}$, and $316^{+202}_{-117}$ M$_{\oplus}$. The halos of IM Lup and DM Tau are dust rich with gas-to-dust mass ratios of 64 and 18, respectively. In all three disks, the dust drift and growth timescales are shorter than the disk ages, implying that the smooth outer disks should not exist. The halos in our sources hold relevant fractions of the total dust reservoir, demonstrating that they play an important role in alleviating the mass-budget problem. While the persistence of halos in IM Lup and DM Tau could be explained by late infall, the presence of centimeter-sized grains in Elias 2-24's halo suggests that unresolved dust traps also play a role.
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All authors Sreejita Das, Enrique Macías, Nicolas T. Kurtovic, Til Birnstiel, Elena M. Viscardi, Pietro Curone

Astrophysics of Galaxies

From Gaia to GaiaNIR: II. A new view of the Milky Way bar

The Milky Way (MW) hosts a central bar whose pattern speed, orientation, and length remain uncertain, largely due to observational biases and selection effects, despite the transformative data provided by the Gaia mission. We aim to reassess the MW bar properties using Gaia DR3, explicitly accounting for incompleteness and astrometric uncertainties, and to quantify the expected improvements from future Gaia DR4, DR5, and GaiaNIR data. We combine Gaia DR3 RGB samples with line-of-sight velocities and realistic Gaia and GaiaNIR mock catalogues to characterise observational biases. We then apply standard techniques to infer the bar pattern speed and structural properties, and evaluate their performance for upcoming data releases. Using Gaia DR3 RGB mock catalogues, we find that the bar pattern speed exhibits a systematic offset of $+14.4 \pm 2.3$ km$~$s$^{-1}~$kpc$^{-1}$. Applying this approach to the data yields $\Omega_p = 43.7 \pm 0.1$ km$~$s$^{-1}~$kpc$^{-1}$, which we interpret as a conservative upper limit. Correcting for this bias gives $\Omega_p = 29.3 \pm 2.3$ km$~$s$^{-1}~$kpc$^{-1}$, although this estimate should be treated with caution given the limited number of mock realizations. We also detect bisymmetric perturbations in $v_\phi$ and $\langle |v_R / v_{\rm tot}| \rangle$, with phase angles $\phi_b = 19$-$24^\circ$ in the bar region. Future Gaia data releases, together with GaiaNIR, are expected to reduce systematic offsets in the pattern speed to $\sim +5$ km$~$s$^{-1}~$kpc$^{-1}$. In addition, GaiaNIR will further improve proper motion precision to below $0.001$ mas$~$yr$^{-1}$ for bright sources and extend the spatial coverage. Our results indicate that current measurements of the MW bar pattern speed are significantly affected by systematics, but that forthcoming Gaia and GaiaNIR data will substantially improve both accuracy and robustness.
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All authors Ó. Jiménez-Arranz, M. Schölch, S. Khanna, L. Chemin, M. Romero-Gómez, J. A. S. Hunt, R. Drimmel, E. Poggio, D. Hobbs, P. J. McMillan, I. Henum, R. P. Church

Earth and Planetary Astrophysics

Sensitivity of Dry Lava Planet Atmospheric Emission Spectra to Changes in Lava Compositions

The atmospheres of hot rocky exoplanets are among the first primary targets of the JWST. Interpreting their atmospheric spectra requires understanding the link between silicate lava compositions and overlying atmospheres. We investigate the sensitivity of simulated emission spectra of dry lava planets to variations in oxide abundances in silicate melt. Our goal is to determine which molten surface features could be distinguishable with future observations. We combine our vaporisation code with gas chemical equilibrium and radiative transfer codes to self-consistently compute atmospheric chemistry and thermal structure. Alongside varying lava compositions, we assess the impact of host star spectral type on emission spectra. TiO2 melt abundance dictates atmospheric TiO, which strongly influences surface temperature and emission spectra due to its short-wave opacity. This creates a degeneracy with heat redistribution efficiency, potentially broken by observing the optical TiO emission feature. Atmospheric SiO and SiO2 abundances depend on melt SiO2 content, with stronger SiO and SiO2 emission features at higher melt abundances. For the currently best observable HREs, changes in TiO2 and SiO2 abundance of about an order of magnitude with respect to BSE, could potentially be observable with 12 JWST eclipse observations.
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All authors Christiaan P. A. van Buchem, Rojita Buddhacharya, Mantas Zilinskas, Sebastian Zieba, Yamila Miguel, Wim van Westrenen

Earth and Planetary Astrophysics

Two Potential Exoplanets around A-type Stars Selected from 18 Planetary Candidates

We screen and analyze exoplanet candidates around A-type stars (defined as Teff between 7500 and 10,000 K) observed by the Transiting Exoplanet Survey Satellite to evaluate their likelihood of being genuine exoplanets. Our analysis involves transit signal searches, light-curve detrending, estimation of nearby-source contamination, and calculation of false-positive probabilities (FPPs). Among the 18 candidates analyzed, four exhibit relatively low FPP values (<15%). Two candidates are excluded from further analysis due to the lack of stellar parameter data. Six candidates show no clearly detectable transit signals, likely due to shallow or weak features, while six candidates exhibit relatively high FPP values, leaving their authenticity uncertain. Among the four low-FPP targets, two-TIC 48031665 and TIC 259230140-stand out as the most promising. TIC 48031665 shows a very shallow transit signal but has a very low FPP and minimal nearby starlight contamination. TIC 259230140 displays a clear U-shaped transit light curve typical of planetary transits, along with slightly higher yet still low FPP and contamination levels. These two objects are therefore considered the most promising candidates identified in this study.
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All authors Yi-fan Luo, Wen-Ping Liao, Sheng-Bang Qian, Wen-Xu Lin, Li-Ying Zhu

Astrophysics of Galaxies

Characterizing the velocity anisotropy of the Milky Way's stellar halo

Modeling the Milky Way stellar halo requires well-determined density and velocity anisotropy profiles. However, it has been challenging to gather a large sample of stars with six-dimensional data that extend beyond 40 kpc to map the outer halo. Our work investigates the velocity anisotropy in the Milky Way stellar halo with more than 10,000 blue horizontal-branch stars, combining Gaia astrometric data and spectroscopic data from SEGUE, DESI and LAMOST. This large sample allows us to obtain a detailed profile of up to $\sim 50$ kpc. Radial velocities are predominant in the inner halo ($< 30$ kpc), and the anisotropy presents a smooth decrease before rapidly dropping to negative values, becoming dominated by tangential dispersion velocities. Removing the main known accreted structures of the Milky Way, makes the anisotropy profile radially-dominated at all radii. Our profile clearly shows an increase in the anisotropy from the center of the Galaxy, in accordance to the simulations. We also investigate the correlation of anisotropy with metallicity and with color. The lack of correlation between metallicity and anisotropy in our clean sample reinforces that this relation is driven by merger events. The initial exploration with color indicates a relation between kinematics and age, showing that older stars are dynamically colder and present less radial orbits than younger stars in the inner halo.
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All authors F. O. Barbosa, A. Pérez-Villegas, S. Rossi, R. M. Santucci, L. Aguilar, H. D. Perottoni, G. Limberg, L. Borbolato, J. V. Nogueira-Santos

Earth and Planetary Astrophysics

Rapid and Predictive Planet Population Synthesis Model (RAPPS) I. Upgraded model and resulting synthetic populations

Exoplanet surveys have revealed a wide diversity of planetary systems, requiring integrated models of planet formation to explain their origin. Planet population synthesis (PPS) modelling is a key tool for linking theory with the statistical properties of observed exoplanets. In the coming decade, the number of known exoplanets is expected to increase ten-fold, with a significant expansion in the range of planetary parameters probed by upcoming missions. We aim to develop a new PPS model capable of predicting planetary masses, radii, orbits, and atmospheric properties across diverse stellar hosts, while maintaining high computational efficiency for statistical comparison with observations. We build upon our previous model, which included water enrichment of primordial atmospheres via magma-gas interactions, and extend it by incorporating a semi-analytical treatment of post-disc dynamical evolution in multiplanet systems. Additional updates include revised prescriptions for disc evolution, resonance trapping, and atmospheric escape. The updated model produces planetary distributions that differ from our previous results, particularly in the abundance of Earth- and sub-Earth-mass planets. These differences arise mainly from the new dynamical evolution model and show improved agreement with simulations based on direct N-body integrations. Atmospheric enrichment is also found to strongly influence both the occurrence of gas giants and the radius distribution of close-in super-Earths and sub-Neptunes. The upgraded model provides a computationally efficient and physically comprehensive framework for predicting planetary populations across a wide range of stellar environments, enabling large parameter surveys and robust statistical comparisons with observations.
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Astrophysics of Galaxies

From Gaia to GaiaNIR: I. Probing dark matter halos in globular clusters

The proposed GaiaNIR mission would extend Gaia's astrometric capabilities into the near-infrared, improving astrometric precision and enabling observations in heavily dust-obscured regions. In this work, we investigate the impact of GaiaNIR on the detectability of dark matter halos in globular clusters by comparing its performance with that of Gaia. Expected observations from future Gaia data releases and GaiaNIR are modeled for a globular cluster with properties similar to M4. The cluster is simulated with a range of dark matter halo sizes and varying levels of extinction, allowing a direct assessment of each mission's ability to detect and distinguish dark matter halos across different extinction conditions. To support this comparison, the relationship between the Gaia G band and several near-infrared bands is examined. We find that Gaia can resolve extended dark matter halos in low-extinction conditions, but its performance degrades significantly as extinction increases. In contrast, GaiaNIR reduces statistical uncertainties and retains sensitivity to extended halos even with strong extinction. These results indicate that GaiaNIR would both strengthen constraints on kinematic signatures accessible to Gaia and enable the study of clusters in heavily obscured regions that are currently beyond Gaia's reach.
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All authors I. Henum, D. Hobbs, Ó. Jiménez-Arranz, P. J. McMillan, R. P. Church

Earth and Planetary Astrophysics

Impact of Cold Jupiter Scattering on the Mean-Motion Resonance of Inner Small Planets

A key feature of close-in, multiple super-Earth (SE) systems is the tendency for adjacent planet pairs to lie just wide of low-order mean-motion resonances (MMR). This period ratio distribution has motivated numerous theoretical studies, particularly those invoking post-disk processes that perturb initially resonant architectures. We investigate whether orbital instability among cold Jupiters (CJs) can perturb inner SE systems initially in MMR. We show that a single pericenter passage of a highly eccentric CJ can disrupt inner resonances once a critical perturbation strength is exceeded, increasing the libration amplitude of the resonant angles. However, N-body simulations show that deep penetration of CJs into the inner system is uncommon, with $\lesssim 10-20\%$ of cases reaching $\lesssim 10\%$ of the initial semi-major axis of the innermost CJ. Motivated by these results, we use secular perturbation theory to quantify the impact of time-dependent forcing from scattering CJs on the eccentricity and resonant-angle evolution of inner SEs. We find that for typical systems (e.g., with SEs at $\sim 0.1$ au and CJs at a few au), such forcing can efficiently disrupt resonances, driving resonance-angle circulation in most systems ($\gtrsim 60\%$ for 2:1 and $\sim 85\%$ for 3:2 configurations). Thus, even when the "final" CJ has little effect on the "current" SEs, its earlier scattering history can leave significant imprints on the system architecture. This mechanism, and similar ones involving more abundant cold Neptunes, provide a natural source of dynamical "kicks" and offer a pathway for producing the observed trough-peak structure in the period ratio distribution of Kepler multi-planet systems.
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Cosmology and Nongalactic Astrophysics

Galaxy Populations in the IllustrisTNG Caustic Skeleton

The caustic skeleton is a parameter-free and mathematically rigorous formalism for tracing the hierarchical formation history of the multiscale cosmic web from the singularities in the underlying dark matter flow. In the present study, we explicitly use the multistreaming nature of the cosmic mass distribution to address the influence of the weblike embedding on the galaxy populations and discern their properties in different web environments. To this end, we construct the multiscale caustic skeleton of the dark mass distribution in the state-of-the-art suite of the large-scale IllustrisTNG simulations. In addition to the multistreaming dark matter density field, we assess the characteristic properties of the intergalactic baryonic gas in the vicinity of the caustics. Next, we associate the galaxies with the voids, walls, filaments and cluster nodes, and investigate their colours and star formation activities. A unique feature of the analysis is that it explicitly addresses the multiscale aspects with respect to the galaxy population, assessing issues such as the fraction of (blue) galaxies as a function of the scale of the cosmic web pattern and its caustic features. We find that the galaxy properties form a continuum in the scale-space cosmic web. Intimately coupled to the hierarchical build-up of the cosmic structure, it also allows us to systematically assess the impact of the formation time of the various structural components of the cosmic web on the galaxy properties. This furthers insight into the establishment of the observed colour-density relation of galaxies.
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Solar and Stellar Astrophysics

Understanding the complex morphology of a CME II: how pre-eruptive conditions shape CME evolution

The morphology and heliospheric impact of coronal mass ejections (CMEs) are strongly shaped by their preeruptive magnetic configuration and surrounding coronal environment, yet these influences remain difficult to constrain observationally. We analyze a complex CME that erupted on 2024 October 26 using multiviewpoint remote sensing observations and in situ measurements. Using the physics based CORHELCME magnetohydrodynamic model, we test multiple physically plausible realizations of the preeruptive magnetic flux rope (MFR) and background magnetic field, using agreement with the observed evolution as a constraint on the CMEs initial state. We find that modest changes in MFR footpoint location and force balance lead to substantially different coronal trajectories, enabling rapid discrimination among candidate initial states. While several configurations reproduce the CMEs large scale propagation, realistic small scale morphology is achieved only when a near dated background magnetic field is employed. The resulting simulation reproduces key morphologies observed from three viewpoints without fine tuning, indicating that the inferred preeruptive configuration represents a robust, global solution and provides a physically consistent interpretation of their magnetic origin. Comparison with in situ shock detections highlights the role of CME solar wind interactions in shaping heliospheric signatures, though shock arrival times remain uncertain at the 11 hr level. These results demonstrate that data informed, physics based modeling can meaningfully constrain CME preeruptive conditions and bridge remote and in situ observations, while emphasizing the need for timely magnetic field measurements to improve predictive capability.
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All authors Abril Sahade, Cecilia Mac Cormack, Angelos Vourlidas, Teresa Nieves-Chinchilla, Cooper Downs, Clementina Sasso, Judith Karpen

Astrophysics of Galaxies

The Metal Content of Resolved Galaxies

We present a homogeneous metallicity analysis of old stellar populations in Local Volume (LV) galaxies using data from the CMDs/TRGB catalog of the Extragalactic Distance Database (EDD; http://edd.ifa.hawaii.edu), which provides uniformly measured TRGB distances and PSF photometry for resolved stars in over 500 nearby galaxies observed with the Hubble Space Telescope. We apply the calibration of Lee et al.(1993) to estimate the mean metallicity [Fe/H] from the (V-I) color of the red giant branch (RGB) at M_I = -3.5 mag obtaining reliable measurements for 334 galaxies out of an initial set of 558. The RGB colors were derived by locating the maximum stellar density in the (M_I, (V-I)) diagram, smoothed with a Gaussian kernel and refined via Monte Carlo simulations (500-1000 realizations), yielding typical uncertainties of about 0.03 mag. Our results show that most galaxies lie within the color range (V-I) = 1.22-1.74 of the original calibration, corresponding to metal-poor systems typical of dwarfs, with the overall metallicity distribution peaking at [Fe/H] = -1.89+-0.03 dex. We find a pronounced luminosity-metallicity relation across a wide magnitude range, from faint dwarfs (M_B > -7) mag to giant galaxies (M_B < -18), described by the regression [Fe/H] = -2.6- 0.075M_B. Both dwarf and giant galaxies follow the same relation, though ACS fields for giants often sample outer, more metal-poor regions. Morphologically, early-type dwarf spheroidals exhibit systematically higher mean metallicities than late-type dwarf irregulars.
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All authors Lidia N. Makarova, Denis G. Purytin, R. Brent Tully, Gagandeep S. Anand

High Energy Astrophysical Phenomena

Latest results from the IceCube Neutrino Observatory

The IceCube Neutrino Observatory has opened a new window into the high-energy Universe, providing measurements of neutrinos over a broad energy range. This contribution presents recent results, including a follow-up on the first identification of a steady neutrino source NGC 1068, measurements of the flavor composition of the diffuse astrophysical flux, limits on prompt atmospheric neutrinos, and searches for neutrinos from dark matter annihilation in the Sun. These measurements probe neutrino production mechanisms, fundamental particle interactions, and physics beyond the Standard Model. Looking forward, the recently deployed IceCube Upgrade will enhance sensitivity to lower-energy neutrinos and reduce systematic uncertainties, while the planned IceCube-Gen2 will expand the detector volume, increase the neutrino detection rate, and extend energy reach, enabling more detailed studies of cosmic sources and high-energy particle physics.
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Astrophysics of Galaxies

Gravitational Waves from Cosmic Dawn: Tracing Cosmic Black Hole Binaries with ET, LGWA, and LISA

Next-generation detectors, such as LISA, LGWA, and ET, will for the first time probe the high redshift Universe, offering unique insight into the birth, growth, and dynamics of the first black holes (BHs) during their earliest stages of formation. We aim to predict merger rates and gravitational wave (GW) signatures of "cosmic" binary BHs forming as a result of galaxy mergers at $z\geq 4$. We investigate how BH seeding, accretion physics, and dynamical delays affect their properties and detectability across cosmic epochs. We used the semi-analytic model Cosmic Archaeology Tool (CAT) to trace the evolution and delayed mergers, driven by dynamical friction, of BH binaries formed from light, medium-weight, and heavy seeds under Eddington-limited (EL) and super-Eddington (SE) accretion prescriptions. We employed the GWFish package to evaluate their GW signals and detectability by LISA, LGWA, and ET. Our results show the impact of BH accretion and seeding prescriptions on the properties and distribution of detectable sources. In the EL model, the detected populations are dominated by nearly equal-mass binaries ($\tilde{q} = 0.7$). In contrast, SE growth leads to lower mass ratios for LISA detections ($\tilde{q} \sim 0.2$) and medium ratios for ET and LGWA ($\tilde{q} \sim 0.4$ and $0.3$, respectively). We present the total detection rates predicted under the two accretion scenarios. The SE model allows BHs to grow faster, transferring a significant fraction of detectable systems from the ET band to the LISA band, compared to the EL model. As a result, the predicted LISA detection rate increases from ~ 32 yr$^{-1}$ in the EL case to ~ 64 yr$^{-1}$ in the SE scenario, and the ET detection rate reduces from ~ 64 yr$^{-1}$ in the EL model to only ~ 4 yr$^{-1}$ in the SE scenario. In both scenarios, LGWA yields comparable detection rates (~ 21 yr$^{-1}$ in EL and ~ 12 yr$^{-1}$ in SE).
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All authors Nazanin Davari, Rosa Valiante, Alessandro Trinca, Raffaella Schneider, Riccardo Caleno, Monica Colpi, Manuel Arca Sedda, Matteo Bonetti, Alessandro Lupi, Roberto Decarli, Alberto Sesana

Astrophysics of Galaxies

On the relative CNO underabundance in quasar absorption systems at $z \sim 3$ arising from Population III enrichment and attenuation by intermediate-mass black holes and primordial baryon accretion

This article uses an adapted version of the semi-analytical model of cosmic chemical enrichment developed by \citet{Corazza_2022} to reproduce the observed abundances of C, N, and O in absorption systems of quasar spectra (ASQS) at $z \gtrsim 3-6$, addressing an overproduction issue of the abovementioned elements. We address this discrepancy by updating the cosmic star formation rate (CSFR) and introducing intermediate-mass black holes (IMBHs) as permanent matter sinks without accounting for a dynamic cosmic mass accretion rate. Our results indicate that IMBHs act as essential metallicity attenuators through mass sequestration, providing the physical regulation necessary to reconcile theoretical yields with observed data. We show that the interplay between Pop III yields, the cosmic baryon accretion rate (CBAR) from primordial nucleosynthesis, and mass sequestration by IMBHs mitigates the CNO excess. This work reinforces the role of black hole-driven processes in the chemical evolution of the Universe and identifies IMBH accretion rates as a primary area for future refinement.
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High Energy Astrophysical Phenomena

Equation of State for warm Neutron Star outer crusts

We describe the equation of state (EoS) of a warm ion plasma as obtained by performing microscopic many-body simulations using Molecular Dynamics computational techniques. Using the cold one-component plasma (OCP) composition in the Neutron Star (NS) outer crust assumed in \cite{Murarka_2022} with a representative heavy nucleus for each density, we refine previous calculations. We include electron screening and modeling of ions as finite-size Gaussian distributions in the interaction potential, together with an efficient Ewald energy summation procedure. From this, the EoS relation $P(n_B,T)$ is obtained as a function of baryonic number density $n_B\in[7.48\times 10^{-10},2.09\times10^{-4}]$ $ \rm fm^{-3}$ and temperature $k_{B}T\in[1,5]$ MeV in the NS outer crust conditions. In order to improve the usability of our results we provide tabulated data values along with a neural network parametrization available in the Zenodo repository, see https://doi.org/10.5281/zenodo.15348712. We find that even at moderate temperatures, thermal effects of ions are key in the higher density region closer to the inner crust, when described using a thermal effective parametrization based on the thermal adiabatic index $\Gamma_{th}$. We compare our results with other EoS in the literature performing a critical discussion.
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