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Physics Astrophysics

astro-ph Watch Astrophysics

Friday 14 November

Astrophysics of Galaxies

PAH Marks the Spot: Digging for Buried Clusters in Nearby Star-forming Galaxies

Gabrielle B. Graham, Daniel A. Dale, Chase L. Smith et al. (+39 more)

The joint capabilities of the Hubble Space Telescope (HST) and JWST allow for an unparalleled look at the early lives of star clusters at near- and mid-infrared wavelengths. We present here a multiband analysis of embedded young stellar clusters in 11 nearby, star-forming galaxies, using the PHANGS-JWST and PHANGS-HST datasets. We use the Zooniverse citizen science platform to conduct an initial by-eye search for embedded clusters in near-UV/optical/near-infrared images that trace stellar continuum emission, the Paschen$\alpha$ and H$\alpha$ recombination lines, and the 3.3 $\mu$m polycyclic aromatic hydrocarbon feature and its underlying continuum. With this approach, we identify 292 embedded cluster candidates for which we characterize their ages, masses, and levels of line-of-sight extinction by comparing the photometric data to predictions from stellar population models. The embedded cluster candidates have a median age of 4.5 Myr and an average line-of-sight extinction $\left< A_V \right> = 6.0$ mag. We determine lower limits on source stellar masses, resulting in a median stellar mass of $10^3$ $M_{\odot}$. We use this sample of embedded cluster candidates to train multiple convolutional neural network models to carry out deep transfer learning-based searches for embedded clusters. With the aim of optimizing models for future catalog production, we compare results for four variations of training data using two neural networks. Confusion matrices for all eight model configurations, as well as inter-model identification trends, are presented. With refinement of the training sample, we determine that optimized models could serve as a pathway for future embedded cluster identification beyond our 11 galaxy sample.
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All authors Gabrielle B. Graham, Daniel A. Dale, Chase L. Smith, Elisabeth Brann, Kaycee D. Conder, Samuel Crowe, Sumitra Dhileepkumar, Nicole A. Imming, Emilio Mendez, Zachary Pleska, Kelsey Sako, Amirnezam Amiri, Ashley T. Barnes, Médéric Boquien, Rupali Chandar, Ryan Chown, Oleg Y. Gnedin, Kathryn Grasha, Stephen Hannon, Hamid Hassani, Rémy Indebetouw, Hwihyun Kim, Jaeyeon Kim, Hannah Koziol, Kirsten L. Larson, Janice C. Lee, Adam K. Leroy, Elias K. Oakes, M. Jimena Rodríguez, Erik Rosolowsky, Karin Sandstrom, Eva Schinnerer, Jessica Sutter, David A. Thilker, Leonardo Ubeda, Bradley C. Whitmore, Tony D. Weinbeck, Thomas G. Williams, Aida Wofford, J. Eduardo Méndez-Delgado, Qiushi Chris Tian, the PHANGS Collaboration

Solar and Stellar Astrophysics

The Atmospheric Response to Large Electron Beam Fluxes in Solar Flares III: Comprehensive Modeling of the Brightest Observed Near-Ultraviolet Continuum Source in an X9 Solar Flare

Adam F. Kowalski

I report on the high resolution spectra of the remarkable X9 solar flare of 2024 Oct 03 (SOL2024-10-03T12:08) and evaluate the extent to which nonthermal electron beams that generate dense chromospheric condensations can power very bright kernels in solar flares. 1D Radiative-hydrodynamic models predict extreme H$\alpha$ near-wing broadening, bright continuum intensities, and a rapid Fe II red wing asymmetry evolution at the brightest NUV continuum source in the flare. Detailed comparisons to the spectral observations reveal that the H$\alpha$ line is too broad, the Fe II red wing is too bright, and the NUV continuum decays too slowly in a fiducial high-flux beam model. However, chromospheric condensations with maximum electron densities of $n_e \approx 5 \times 10^{14}$ cm$^{-3}$ and optical depths $\tau \approx 1$ in the near wing of H$\alpha$ are consistent with the observed intensity of a broad spectrum in the Southern ribbon. Model similarities demonstrate that Fe I emission lines and the FUV continuum intensity can form at chromospheric heights during flares, but I find that the ratios of the NUV to FUV continuum intensities are generally too large in the models. This suggests that radiative-hydrodynamic models of chromospheric condensations cool through $T \approx 30,000$ K too rapidly. The larger than expected FUV continuum intensities are not nearly bright enough to explain recent stellar megaflare spectra from the Hubble Space Telescope.
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High Energy Astrophysical Phenomena

Disk mass predictions for binary neutron star mergers: limitations of proposed symbolic regression models

Francois Foucart

Modeling disk formation and mass ejection in binary neutron star systems is an important component in the construction of models for the electromagnetic signals powered by these events. Most models rely on analytical formulae for the disk mass and dynamical ejecta that are fitted to the results of numerical simulations, yet these fits have large uncertainties that significantly limit our ability to extract information from merger observations. In a recent manuscript, Darc et al claim that disk mass formulae constructed using symbolic regression outperform existing formulae and robustly extend to regions of the parameter space outside of the fitting region. I show here that the improvement over the most directly comparable existing model comes mostly from the use of different error measures in optimizing the fitting parameters. For the limited training data used so far, that existing fitting formula has a performance similar to symbolic regression models when optimized over the same error measure. More importantly, I show that many of the formulae obtained through symbolic regression provide unphysical results when used over the whole range of parameters relevant to the modeling of binary neutron star mergers, making them dangerous to use within parameter estimation pipelines. I conclude that fitting formulae with more physics input (e.g. Lund et al 2025), albeit certainly imperfect, remain safer to use in data analysis than these symbolic regression results. Symbolic regression results used in conjunction with careful physics-based vetting may however outperform them in the future.
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Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc

Testing general relativity with amplitudes of subdominant gravitational-wave modes

Ish Gupta, Purnima Narayan, Lionel London et al. (+2 more)

We present an improved subdominant-mode amplitude (SMA) test of general relativity (GR), which probes amplitude-level deviations in the higher-order modes of gravitational-wave (GW) signals from binary black hole mergers while keeping the dominant quadrupole mode fixed. Using a comprehensive parameter-estimation campaign, we benchmark the test against Gaussian noise fluctuations, waveform modeling systematics, and physical effects such as spin precession and orbital eccentricity. When applied to numerical-relativity simulations, the SMA test performs reliably for aligned-spin and mildly precessing systems but exhibits measurable biases for strongly precessing or eccentric binaries. Although designed to detect amplitude deviations, the test also responds coherently to phase perturbations, yielding apparent GR violations when applied to phase-modified waveforms. Applied to recent GW detections, we report the strongest constraint on the hexadecapolar $(4,4)$ mode amplitude deviation, $\delta A_{44} = -0.30^{+1.16}_{-3.45}$, consistent with GR. With these results, this work establishes the SMA test as a robust and broadly sensitive null test of general relativity and demonstrates a systematic approach for assessing the robustness of GW tests of GR.
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All authors Ish Gupta, Purnima Narayan, Lionel London, Shubhanshu Tiwari, Bangalore Sathyaprakash

Solar and Stellar Astrophysics

A new estimate of the zero-point shift of the Gaia DR3 parallaxes obtained from a comparison with VLBI measurements of masers and radio stars

Vadim V. Bobylev

The most complete sample of radio stars and masers with trigonometric parallaxes measured by the VLBI method, common with the Gaia EDR3 and Gaia DR3 catalogs, has been compiled using literature data. The sample contains 151 stars. An analysis of the differences in parallaxes and proper motions of Gaia-VLBI stars has been performed. A new estimate of the systematic shift of the Gaia parallax zero point relative to the inertial coordinate system has been obtained: $\Delta\pi=-0.038\pm0.011$ mas. The obtained estimates of the relative rotation rates confirm the absence of a significant rotation of the Gaia\,DR3 system relative to the extragalactic coordinate system, which in this case is represented by VLBI measurements.
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High Energy Astrophysical Phenomena

Modeling X-ray photon pile-up with a normalizing flow

Ole König, Daniela Huppenkothen, Douglas Finkbeiner et al. (+5 more)

The dynamic range of imaging detectors flown on-board X-ray observatories often only covers a limited flux range of extrasolar X-ray sources. The analysis of bright X-ray sources is complicated by so-called pile-up, which results from high incident photon flux. This nonlinear effect distorts the measured spectrum, resulting in biases in the inferred physical parameters, and can even lead to a complete signal loss in extreme cases. Piled-up data are commonly discarded due to resulting intractability of the likelihood. As a result, a large number of archival observations remain underexplored. We present a machine learning solution to this problem, using a simulation-based inference framework that allows us to estimate posterior distributions of physical source parameters from piled-up eROSITA data. We show that a normalizing flow produces better-constrained posterior densities than traditional mitigation techniques, as more data can be leveraged. We consider model- and calibration-dependent uncertainties and the applicability of such an algorithm to real data in the eROSITA archive.
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All authors Ole König, Daniela Huppenkothen, Douglas Finkbeiner, Christian Kirsch, Jörn Wilms, Justina R. Yang, James F. Steiner, Juan Rafael Martínez-Galarza

High Energy Astrophysical Phenomena · Cross-listed from quant-ph

Relativistic Maxwell-Bloch Equations with Applications to Astrophysics

Ningyan Fang, Victor Botez, Fereshteh Rajabi et al. (+1 more)

We derive relativistic Maxwell-Bloch equations for potential applications in astronomical environments, where various radiative processes are known to occur, including the maser action and Dicke's superradiance. We show that for both phenomena a radiating system's response is preserved at different relative velocities between the system's rest frame and the observer, while the relevant timescales and the radiation intensity transform as expected from relativistic considerations. We verify that the level of coherence between groups of emitters travelling at different speeds is unchanged in all reference frames. We also derive relativistic versions of the maser equations applicable in the steady-state regime.
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All authors Ningyan Fang, Victor Botez, Fereshteh Rajabi, Martin Houde

Astrophysics of Galaxies

Radial dust distributions and obscuring geometry in AGN from JWST/MIRI spectroscopy

Ruiyu Pan and Arkaprabha Sarangi

The spatial distribution of obscuring dust in active galactic nuclei (AGN) is critical for distinguishing between static torus models and dynamical disk-wind scenarios. To constrain this geometry, we forward-model the rest-frame $5$–$14\,\mu\mathrm{m}$ JWST/MIRI MRS spectra of 25 local AGN using a three-dimensional, axisymmetric radiative-transfer library combined with empirical starburst templates. Using a grid-based inference framework, we systematically compare radial dust-density laws of the form $n(r)\propto r^{-p}$ over the range $p=0.5$–$2.0$. Our model comparison strongly favours shallow radial profiles at the sample level: 20 sources achieve their largest statistical weight at $p=0.5$, and 21 accumulate more than half of their combined density-law weight at $p\leq1$. This tendency remains robust even when the likelihood power $\beta$ is varied, although the preferred profile of individual sources can change. Furthermore, the $9.7\,\mu\mathrm{m}$ silicate feature exhibits a distinct trend: absorption minima remain near $9.7\,\mu\mathrm{m}$, whereas four observed emission maxima are shifted redward by approximately $0.8$–$1.3\,\mu\mathrm{m}$. These results favour relatively extended MIR-emitting dust distributions rather than strictly compact geometries, and suggest that an interplay of radiative-transfer effects and intrinsic dust grain properties drives the observed spectral diversity.
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Astrophysics of Galaxies

ODIN: Characterizing the Three-dimensional Structure of Two Protocluster Complexes at $z = 3.1$

Vandana Ramakrishnan, Ashley Ortiz, Byeongha Moon et al. (+52 more)

We present a detailed study of the 3D morphology of two extended associations of multiple protoclusters at $z=3.1$. These protocluster 'complexes', designated COSMOS-z3.1-A and COSMOS-z3.1-C, are the most prominent overdensities of $z=3.1$ Ly$\alpha$ emitters (LAEs) identified in the COSMOS field by the One-hundred-deg$^2$ DECam Imaging in Narrowbands (ODIN) survey. These protocluster complexes have been followed up with extensive spectroscopy from Keck, Gemini, and DESI. Using a probabilistic method that combines photometrically selected and spectroscopically confirmed LAEs, we reconstruct the 3D structure of these complexes on scales of $\approx$50 cMpc. We validate our reconstruction method using the IllustrisTNG300-1 cosmological hydrodynamical simulation and show that it consistently outperforms approaches relying solely on spectroscopic data. The resulting 3D maps reveal that both complexes are irregular and elongated along a single axis, emphasizing the impact of sightline on our perception of structure morphology. The complexes consist of multiple density peaks, ten in COSMOS-z3.1-A and four in COSMOS-z3.1-C. The former is confirmed to be a proto-supercluster, similar to Hyperion at $z=2.4$ but observed at an even earlier epoch. Multiple `tails' connected to the cores of the density peaks are seen, likely representing cosmic filaments feeding into these extremely overdense regions. The 3D reconstructions further provide strong evidence that Ly$\alpha$ blobs preferentially reside in the outskirts of the highest density regions. Descendant mass estimates of the density peaks suggest that COSMOS-z3.1-A and COSMOS-z3.1-C will evolve to become ultra-massive structures by $z=0$, with total masses $\log(M/M_\odot) \gtrsim 15.3$, exceeding that of Coma.
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All authors Vandana Ramakrishnan, Ashley Ortiz, Byeongha Moon, Eunsoo Jun, David Schlegel, Kyoung-Soo Lee, Jessica Nicole Aguilar, Maria Celeste Artale, David Brooks, Maria Candela Cerdosino, Robin Ciardullo, Todd Claybaugh, Andrei Cuceu, Axel de la Macorra, Arjun Dey, Nicole M. Firestone, Andreu Font-Ribera, Jaime E. Forero-Romero, Eric Gawiser, Enrique Gaztañaga, Caryl Gronwall, Lucia Guaita, Gaston Gutierrez, Sungryong Hong, Ho Seong Hwang, Sang Hyeok Im, Paulina Troncoso Iribarren, Woong-Seob Jeong, Dick Joyce, Ankit Kumar, Claire Lamman, Martin Landriau, Seong-Kook Lee, Jaehyun Lee, Aaron Meisner, Ramon Miquel, John Moustakas, Seshadri Nadathur, Gautam Nagaraj, Julie Nantais, Nelson Padilla, Changbom Park, Will Percival, Francisco Prada, Ignasi Pérez-Ràfols, Graziano Rossi, Eusebio Sanchez, Joseph Harry Silber, Hyunmi Song, David Sprayberry, Gregory Tarlé, Francisco Valdes, Yujin Yang, Ann Zabludoff, Hu Zou

Earth and Planetary Astrophysics

The Transition from Giant Planets to Brown Dwarfs beyond 1 au from the Stellar Metallicity Distribution

Steven Giacalone, Andrew W. Howard, Gregory J. Gilbert et al. (+3 more)

Giant planets and brown dwarfs are thought to form via a combination of pathways, including bottom-up mechanisms in which gas is accreted onto a solid core and top-down mechanisms in which gas collapses directly into a gravitationally-bound object. One can distinguish the prevalence of these mechanisms using host star metallicities. Bottom-up formation thrives in metal-rich environments, whereas top-down formation is weakly dependent on ambient metal content. Using a hierarchical Bayesian model and the results of the California Legacy Survey (CLS), a low-bias and homogeneously analyzed radial velocity survey, we find evidence for a transition in the stellar metallicity distribution at a companion mass of $\gamma = 27_{-8}^{+12} \, M_{\rm Jup}$ for companions with orbital separations between $1-50$ au. Companions below and above this threshold tend to orbit stars with higher ($\rm{[Fe/H]} = 0.17 \pm 0.12$ dex) and lower ($\rm{[Fe/H]} = -0.03 \pm 0.10$ dex) metallicities, respectively. Previous studies of relatively close-in companions reported evidence of a lower transition mass of $\leq 10 \, {\rm M_{\rm Jup}}$. When applied to the CLS sample, our model predicts the probability of a transition in the stellar metallicity distribution at or below $10 \, { M_{\rm Jup}}$ to be $< 1 \%$. We compare our results to estimates of $\gamma$ gleaned from other observational metrics and discuss implications for planet formation theory.
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All authors Steven Giacalone, Andrew W. Howard, Gregory J. Gilbert, Judah Van Zandt, Erik A. Petigura, Luke B. Handley

Earth and Planetary Astrophysics

On the coincidence between the close passage of HD7977 and the Pliocene-Pleistocene transition

Zhuoya Cao, Abraham Loeb and Morgan MacLeod

The Oort Cloud's dynamical evolution is significantly influenced by both the galactic tide and stellar flybys. This study investigates the particular case of HD7977's close encounter 2.47 Myr ago, which likely repopulated the Inner Oort Cloud and potentially triggered a significant comet shower on Earth. Our results demonstrate that the shower's intensity strongly depends on HD7977's impact parameter ($b$), with possible flyby distances ranging from 2,300 AU to $\sim$ 13,000 AU. For the closest approach ($b \sim 2,300$ AU), the terrestrial impact probability of 1 km comets increases by an order of magnitude compared to the steady state, slightly exceeding the asteroid impact probability at this size scale. We propose an analytical method to compute the probability of comet showers impacting Earth, which saves considerable computation time compared to N-body simulations. We identify a threshold diameter $D_0 = 2.25$ km for which yields $P = 1$ in our model, with $D_0$ following a logarithmic dependence on $b$. These findings suggest that HD7977's flyby may have caused an enhanced comet flux during the Pliocene-Pleistocene transition, which could plausibly be related to the environmental changes at this era.
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Cosmology and Nongalactic Astrophysics

Inflation without an Inflaton II: observational predictions

Marisol Traforetti, Mariam Abdelaziz, Daniele Bertacca et al. (+3 more)

We present a complete computation of the scalar power spectrum in the inflation without inflaton (IWI) framework, where the inflationary expansion is driven solely by a de~Sitter (dS) background and scalar fluctuations arise as second-order effects sourced by tensor perturbations. By explicitly deriving and numerically integrating the full second-order kernel of the Einstein equations, we obtain a scale-invariant scalar spectrum without invoking a fundamental scalar field. In this framework, the amplitude of the scalar fluctuations is directly linked to the scale of inflation. More precisely, we show that matching the observed level of scalar fluctuations, $\Delta_{\phi}^2(k_\ast)\approx 10^{-9}$ at Cosmic Microwave Background (CMB) scales, fixes the inflationary energy scale $H_{\rm inf}$ as a function of the number of observed e-folds $N_{\rm obs}$. For $N_{\rm obs}\simeq 30 - 60$, we find $H_{\rm inf} \simeq 5\times 10^{13}\,\mathrm{GeV} - 2\times 10^{10}\,\mathrm{GeV}$, corresponding to a tensor-to-scalar ratio $r \simeq 0.01 - 5\times 10^{-9}$. In particular, requiring consistency with instantaneous reheating, we predict a number of e-folds of order~$\mathcal{O}(50)$ and an inflationary scale $H_{\rm inf} \simeq 10^{11}\,\mathrm{GeV}$. We also incorporate in our framework the quantum break-time of the dS state and show that it imposes an upper bound on the number of particle species. Specifically, using laboratory constraints on the number of species limits the duration of inflation to $N_{\rm obs}\lesssim 126$ e-folds. These results establish the IWI scenario as a predictive and falsifiable alternative to standard inflaton-driven models, linking the observed amplitude of primordial fluctuations directly to the quantum nature and finite lifetime of dS space.
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All authors Marisol Traforetti, Mariam Abdelaziz, Daniele Bertacca, Raul Jimenez, Sabino Matarrese, Angelo Ricciardone

Instrumentation and Methods for Astrophysics

KDP as a thermal blocking filter – Deep near IR observations with a warm narrow band filter

J. K. M. Viuho, A. A. Djupvik, A. N. Sørensen et al. (+5 more)

Ground-based astronomy suffers from strong atmospheric line- and thermal continuum emission, at the near infrared (NIR, 0.7-1.1$\mu$m), and short-wave infrared (SWIR, 1.1-2.5$\mu$m) wavelengths. The thermal continuum emission increases exponentially towards the red sensitivity cutoff of the state-of-the-art 2.5$\mu$m cutoff SWIR detectors. Given availability of an optical quality shortpass filter material with strong blocking density in the SWIR, lower cost instrumentation, and higher performance filters could be designed. We demonstrate monopotassium dihydrogen phosphate (KDP, chemical formula KH$_2$PO$_4$) as a strong candidate for this purpose. KDP is fully transparent at wavelengths from ultraviolet to 1.3$\mu$m, but becomes highly opaque at wavelengths >2$\mu$m. We demonstrate on-sky use of KDP by improving performance of a cryogenic broadband filter with known off-band thermal leak, and using a non-cryogenic narrow band filter for deep observation. KDP reduces the sky background by 4.5 magnitudes in the leaky Z-band filter we use. Our 4nm wide, central wavelength 1.191$\mu$m narrowband filter in combination with KDP reduces the sky surface brightness by three magnitudes compared to a J broadband, although the effect of KDP is minor due to high blocking density of the broadband filter. We find a sky surface brightness of 18.5 mag arcsec$^{-2}$ in our bandpass at 1.191$\mu$m. KDP is an excellent thermal blocker, when its temperature is maintained above its Curie point at 123K. Below Curie point, KDP transforms its crystal structure, degrading its otherwise good imaging properties.
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All authors J. K. M. Viuho, A. A. Djupvik, A. N. Sørensen, D. Kumar, P. Steiner, J. P. U. Fynbo, S. Armas, M. I. Andersen

Astrophysics of Galaxies

LEGA-C stellar populations scaling relations. II: Dissecting mass-complete archaeological trends and their evolution since z~0.7 with LEGA-C and SDSS

Anna R. Gallazzi, Stefano Zibetti, Arjen van der Wel et al. (+11 more)

With a sample of 552 galaxies at z~0.7 from the LEGA-C survey, we investigate how current star formation influences light-weighted mean stellar ages and metallicities, and their median trends with stellar mass or velocity dispersion. The bimodality in the global age-mass relation stems from the different age distributions in the quiescent (Q) and star-forming (SF) populations. A bimodality is not observed in the stellar metallicity-mass relation, although Q and SF galaxies have different distributions in this parameter space. We identify a high-metallicity sequence populated by both Q and weakly SF galaxies. At masses below logM/Msun=10.8 the median stellar metallicity-mass relation of SF galaxies steepens, as a consequence of increasing scatter toward lower stellar metallicities for galaxies with increasing specific star formation rate at fixed mass. With a consistent analysis of SDSS DR7 spectra, accounting for aperture corrections, we quantify the evolution of the stellar age and stellar metallicity scaling relations between z=0.7 and the present. We find negligible evolution in the stellar metallicity-mass relation of Q galaxies and for logM/Msun>11 galaxies in general. Lower mass SF galaxies, instead, have typically lower metallicities than their local counterparts, indicating significant enrichment since z~0.7 in the low-mass regime. The median of the stellar ages of both the general population and Q galaxies has changed by only 2 Gyr between z=0.7 and z=0.1, less than expected from cosmic aging. Some Q galaxies must evolve passively to reach the old boundary of the local population. However, in order to explain the evolution of the median trends, both individual evolution, through rejuvenation and/or minor merging impacting the outer galaxy regions, and population evolution, through quenching of massive, metal-rich star-forming galaxies, are required. (Abridged)
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All authors Anna R. Gallazzi, Stefano Zibetti, Arjen van der Wel, Angelos Nersesian, Yasha Kaushal, Rachel Bezanson, Daniele Mattolini, Eric F. Bell, Laura Scholz-Diaz, Joel Leja, Francesco D'Eugenio, Po-Feng Wu, Camilla Pacifici, Michael Maseda

Astrophysics of Galaxies

Not all cores are equal: Phase-space origins of dynamical friction, stalling and buoyancy

Shashank Dattathri, Frank C. van den Bosch, Uddipan Banik et al. (+4 more)

Dynamical friction governs the orbital decay of massive perturbers within galaxies and dark matter halos, yet its standard Chandrasekhar formulation fails in systems with cores of (roughly) constant density, where inspiral can halt or even reverse, phenomena known respectively as core stalling and dynamical buoyancy. Although these effects have been observed in simulations, the conditions under which they arise remain unclear. Using high-resolution N-body simulations and analytic insights from kinetic theory, we systematically explore the physical origin of these effects. We demonstrate that the overall distribution function (DF) of the host, not just its central density gradient, determines the efficiency and direction of dynamical friction. Core stalling arises when the perturber encounters a plateau in the DF, either pre-existing or dynamically created through its own inspiral, while buoyancy emerges in systems whose DFs possess an inflection that drives an unstable dipole mode. We show that double power-law density profiles with rapid outer-to-inner slope transitions naturally produce such DF features, which is why structurally similar cores can yield radically different dynamical outcomes. Our results provide a unified framework linking the phase-space structure of galaxies to the fate of embedded massive objects, with direct implications for off-center AGN, the dynamics of nuclear star clusters, and the stalled coalescence of black holes in dwarf galaxies and massive ellipticals.
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All authors Shashank Dattathri, Frank C. van den Bosch, Uddipan Banik, Martin Weinberg, Priyamvada Natarajan, Zhaozhou Li, Avishai Dekel

Earth and Planetary Astrophysics

Rock vapour is opaque: implications for dynamics and observations of lava planets

T. Giang Nguyen, Nicolas B. Cowan, Gunnar Montseny Gens et al. (+3 more)

Extreme instellation on lava planets causes the rocky surface to melt and vaporize. Because the rock vapour composition is intrinsically tied to the mantle, atmospheric characterization of lava planets can hold valuable insight into the interior processes of rocky planets. To help interpret current data and strategize for future observations, we develop the model SonicVapour to simulate the dynamics of chemically complex secondary atmosphere of lava planets. We find that for planets with surface temperatures exceeding 2700 K, the rock vapour outgassed is optically thick, making the atmosphere vertically isothermal thus suppressing convection and severely limiting atmospheric detection via emission spectroscopy. In contrast, cooler planets with surfaces between 2300 K - 2700 K have an atmospheric opacity close to 50% and produce distinct spectral features. Counter-intuitively, therefore, cooler lava planet atmospheres are easier to detect. Our results ultimately emphasize the importance of considering atmospheric "detectability" in tandem with signal-to-noise for future observation programs.
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All authors T. Giang Nguyen, Nicolas B. Cowan, Gunnar Montseny Gens, Charles-Edouard Boukare, William Eaton, Karolina Sienko

High Energy Astrophysical Phenomena

Hydrodynamic instabilities in long-term three-dimensional simulations of neutrino-driven supernovae of 13 red supergiant progenitors

Beatrice Giudici, Michael Gabler and Hans-Thomas Janka

We present long-term three-dimensional (3D) simulations of Type-IIP supernovae (SNe) for 13 non-rotating, single-star, red-supergiant (RSG) progenitors with zero-age-main-sequence masses between 12.5 M$_{\odot}$ and 27.3 M$_{\odot}$. The explosions were modelled with a parametric treatment of neutrino heating to obtain defined energies, ${}^{56}$Ni yields, and neutron-star properties in agreement with previous results. Our 3D SN models were evolved from core bounce until 10 days to study how the large-scale mixing of chemical elements depends on the progenitor structure. Rayleigh-Taylor instabilities (RTIs), which grow at the (C+O)/He and He/H interfaces and interact with the reverse shock forming after the SN shock has passed the He/H interface, play a crucial role in the outward mixing of ${}^{56}$Ni into the hydrogen envelope. We find most extreme ${}^{56}$Ni mixing and the highest maximum ${}^{56}$Ni velocities in lower-mass (LM) explosions despite lower explosion energies, and the weakest ${}^{56}$Ni mixing in the 3D explosions of the most massive RSGs. The efficiency of radial ${}^{56}$Ni mixing anti-correlates linearly with the helium-core mass and correlates positively with the magnitude of a local maximum of $\rho r^3$ in the helium shell. This maximum causes shock deceleration and therefore facilitates high growth factors of RTI at the (C+O)/He interface in the LM explosions. Therefore fast-moving ${}^{56}$Ni created by the asymmetric neutrino-heating mechanism is carried into the ubiquitous RT-unstable region near the He/H interface and ultimately far into the envelopes of the exploding RSGs. Our correlations may aid improving mixing prescriptions in 1D SN models and deducing progenitor structures from observed SN properties..
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2511.11796 · 14 Nov · 38 pages, 27 figures, 6 tables. Accepted by MNRAS. Substantial revision: More details on early evolution (4.1), with figures of the 3D geometry of all models. Asymmetries are quantified by di-/quadrupole amplitudes of Ni ejecta and of the shock at breakout (correlate only weakly with the kick). Extended discussion of correlations vs. causal links between progenitor/explosion properties and mixing

Abstract PDF $NTRN ×3$SNOV ×2$STAR ×2$NEUT ×1

Cosmology and Nongalactic Astrophysics

Non-Parametric Reconstruction of the Hubble Parameter from the Fourth Gravitational Wave Transient Catalog and DESI Baryonic Acoustic Oscillations

Grégoire Pierra, Alberto Colombo and Simone Mastrogiovanni

The release of the fourth Gravitational Wave Transient Catalog (GWTC-4.0) by the LIGO-Virgo-KAGRA collaboration includes more than 200 compact binary coalescence (CBC) candidates that can be used to probe the cosmic expansion. The population of merging binary black holes has been used so far to provide a constraint on the Hubble constant and dark matter fraction under the hypothesis of a flat-$\Lambda$-Cold-Dark-Matter Universe. In this work, we provide the first non-parametric constrain on the Hubble parameter from 137 dark sirens reported in GWTC-4.0. We employ the relation between detector and source frame masses for detected GW signals, to obtain a statistical redshift evaluation for the population of binary black holes (BBHs). We model the Hubble parameter as a non-parametric autoregressive process in terms of the scale factor, using splines. In addition, we introduce two novel features: the use of anchor points for $H(z)$ derived from an external probe - here, Baryon Acoustic Oscillations (BAOs) - and a constraining power coefficient that quantifies where the inference is most data-driven by GW detections. We highlight three key findings: (i) using GWs alone, the Hubble parameter determination is the most GW-data-driven around redshift $z = 0.44$, yielding to $H(0.44) = 92.3_{-36.6}^{+29.9}\rm\, km s^{-1} Mpc^{-1}$. Its value at $z = 0$, the Hubble constant, is therefore less constrained by the GW data. (ii) The Hubble parameter inferred from analyses assuming a flat-$\Lambda$CDM cosmological model is strongly affected by the cosmological model assumption. (iii) Introducing an anchor point for $H(z)$ enhances the inferred constraints and provides a clear visualization of the redshift range where GWs contribute most to the constraining power.
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High Energy Astrophysical Phenomena · Cross-listed from gr-qc

Kerr-Bertotti-Robinson Black Holes Surrounded by a Cloud of Strings

Faizuddin Ahmed, İzzet Sakall{\i} and Ahmad Al-Badawi

In a recent study [1], authors introduced a new class of exact space-times in Einstein's gravity, which are Kerr black holes immersed in an external uniform magnetic field that is oriented along the rotational axis. Motivated by this work, we investigate a Kerr-like black hole solution with a cloud of strings surrounded by a uniform magnetic field. For the zero rotation case, the space-time reduces to the Schwarzschild-Bertotti-Robinson black hole with a cloud of strings. Moreover, for zero magnetic field, the metrics simplify to a Kerr-like black hole surrounded by a cloud of strings, and its static counterpart reduces to the Schwarzschild black hole with a cloud of strings.
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Instrumentation and Methods for Astrophysics

Towards Mitigating Systematics in Large-Scale Surveys via Few-Shot Optimal Transport-Based Feature Alignment

Sultan Hassan, Sambatra Andrianomena and Benjamin D. Wandelt

Systematics contaminate observables, leading to distribution shifts relative to theoretically simulated signals-posing a major challenge for using pre-trained models to label such observables. Since systematics are often poorly understood and difficult to model, removing them directly and entirely may not be feasible. To address this challenge, we propose a novel method that aligns learned features between in-distribution (ID) and out-of-distribution (OOD) samples by optimizing a feature-alignment loss on the representations extracted from a pre-trained ID model. We first experimentally validate the method on the MNIST dataset using possible alignment losses, including mean squared error and optimal transport, and subsequently apply it to large-scale maps of neutral hydrogen. Our results show that optimal transport is particularly effective at aligning OOD features when parity between ID and OOD samples is unknown, even with limited data-mimicking real-world conditions in extracting information from large-scale surveys. Our code is available at https://github.com/sultan-hassan/feature-alignment-for-OOD-generalization.
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Cosmology and Nongalactic Astrophysics

Implicit inference of the reionization history with higher-order statistics of the 21-cm signal

Nicolas Cerardi, Sambit K. Giri, Michele Bianco et al. (+9 more)

The Epoch of Reionization (EoR), when the first luminous sources ionised the intergalactic medium, represents a new frontier in cosmology. The Square Kilometre Array Observatory (SKAO) will offer unprecedented insights into this era through observations of the redshifted 21-cm signal, enabling constraints on the Universe's reionization history. We investigate the information content of the average neutral hydrogen fraction ($\bar{x}_{\rm HI}$) in several Gaussian (spherical and cylindrical power spectra) and non-Gaussian (Betti numbers and bispectrum) summary statistics of the 21-cm signal. Mock 21-cm observations are generated using the AA* configuration of SKAO's low-frequency telescope, incorporating noise levels for 100 and 1000 hours. We employ a state-of-the-art implicit inference framework to learn posterior distributions of $\bar{x}_{\rm HI}$ in redshift bins centred at $z=8.0,7.2$ and $6.5$, for each statistic and noise scenario, validating the posteriors through calibration tests. Using the figure of merit to assess constraining power, we find that Betti numbers alone are on average more informative than the power spectra, while the bispectrum provides limited constraints. However, combining higher-order statistics with the cylindrical power spectrum improves the mean figure of merit by $\sim$0.25 dex ($\sim33\%$ reduction in $\sigma(\bar{x}_{\rm HI})$). The relative contribution of each statistic varies with the stage of reionization. With SKAO observations approaching, our results show that combining power spectra with higher-order statistics can significantly increase the information retrieved from the EoR, maximising the scientific return of future 21-cm observations.
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All authors Nicolas Cerardi, Sambit K. Giri, Michele Bianco, Davide Piras, Emmanuel de Salis, Massimo De Santis, Merve Selcuk-Simsek, Philipp Denzel, Kelley M. Hess, M. Carmen Toribio, Franz Kirsten, Hatem Ghorbel

Cosmology and Nongalactic Astrophysics

Testing the cosmological Euler equation: viscosity, equivalence principle, and gravity beyond general relativity

Ziyang Zheng, Malte Schneider and Luca Amendola

We investigate how the cosmological Euler equation can be tested in the presence of viscous dark matter, violations of the equivalence principle (EP), and modifications of gravity, while relying on minimal theoretical assumptions. Extending the previous analysis, we generalize the observable $E_P$, which quantifies EP violation, to $\tilde{E}_P$, discuss the degeneracy between bulk and shear viscosities and EP-violating effects, and explicitly show that the EP can still be tested in the small-viscosity limit. In addition, we identify a model-independent observable, $C_{\rm vis,0}$, which characterizes the present-day dark matter viscosity and can be measured from relativistic galaxy number counts by cross-correlating two galaxy populations. We perform forecasts for three forthcoming Stage-IV surveys: DESI, Euclid, and SKA Phase 2 (SKA2), and find that $C_{\rm vis,0}$ can be tightly constrained, at the level of $\mathcal{O}(10^{-6})$ or better in all cases. Among these surveys, SKA2 provides the tightest constraint, with a $1\sigma$ uncertainty of $1.08 \times 10^{-7}$ on $C_{\rm vis,0}$.
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Solar and Stellar Astrophysics

An optical–mid-infrared color evolution tool for nova identification using WISE data

Joseph Onuegbu, Dafne Guetta, Yael Hillman et al. (+2 more)

We present a novel approach for characterizing nova candidates by exploiting the infrared capabilities of the Wide-field Infrared Survey Explorer (WISE) catalog. We developed a pipeline to identify novae based on well-defined infrared criteria, and leveraging this pipeline, we successfully identified 41 optically confirmed novae in the WISE catalog. In particular, we focus on the color difference between the optical V band and the WISE 3.4 microns W1 band as a diagnostic. We compared their infrared light curves with their optical counterparts. We identified a strong correlation from which we proposed a color difference model that can be used for further identification and characterization of novae. Our analysis validates the mass-loss timescale theory, which predicts that systems with lower accretion rates accumulate larger envelopes and produce more massive ejecta. We also confirm models' prediction that the early color evolution of novae is governed by ejecta expansion and cooling. From our sample statistics, we infer a Galactic nova rate of approximately 40 to 50 novae per year, consistent with modern and infrared-corrected estimates. The resultant model from this work paves the way for future large-scale investigations of nova candidates.
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All authors Joseph Onuegbu, Dafne Guetta, Yael Hillman, Volker Perdelwitz, Massimo Della Valle

Earth and Planetary Astrophysics

Probing the era of giant collisions: millimeter observations of the HD 166191 system

Kadin Worthen, Christine H. Chen, A. Meredith Hughes et al. (+5 more)

We present non-simultaneous ALMA band 7 and SMA observations of the HD 166191 disk, which was recently thought to have a collision in its terrestrial planet zone. Both observations detect dust continuum emission and the ALMA observations detect the 12CO J=3-2 line from the circumstellar disk. We do not detect SiO, a potential indicator of giant collisions, but place a limit on the total SiO mass in the system. Unlike previously observed in the infrared, we do not find evidence for variability at millimeter wavelengths when comparing the ALMA continuum observations from 2024 to the pre-collision SMA observations from 2014. We perform modeling of the CO and continuum visibilities and find that both the CO and dust are marginally spatially resolved and are contained to within 20 au from the central star. The modeling of the CO suggests that the outer regions of the disk are gas rich, although further observations are needed to confirm the total gas mass. The evolutionary state of this system has been debated in the literature, and our observations, while not definitive, are generally consistent with the idea that this disk is similar to an evolved protoplanetary or transition/hybrid disk. This could suggest that collisions in the terrestrial planet zone of HD 166191 are occurring while the disk is in a transitional phase, where the inner few au are depleted of gas. This makes HD 166191 an important object for understanding the transition between protoplanetary and debris disks and the stages at which collisions occur.
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All authors Kadin Worthen, Christine H. Chen, A. Meredith Hughes, Brandon C. Johnson, Isabel Rebollido, Diego E. Garcia, Jamar Kittling, Carey M. Lisse

Cosmology and Nongalactic Astrophysics

Mutated Hilltop Inflation in the Era of Present and Future CMB Experiments

Barun Kumar Pal

In this article we confront both large-field and small-field sectors of mutated hilltop inflation model with the recent observational results. We begin with confrontation of predictions from mutated hilltop inflation with the joint analysis of Planck-2018 and BICEP/Keck-2018 data. Subsequently, we extend our analysis by incorporating the ACT-DR6 data in combination with Planck-2018, BICEP/Keck-2018, and DESI-Y1 observations. In both cases, the predictions of mutated hilltop inflation show good consistency with the observational constraints. We have also forecasted the constraints on mutated hilltop inflation model from upcoming CMB experiments, LiteBIRD and Simons Observatory along with their combinations. Here also we find that the prediction from mutated hilltop inflation are in tune with those upcoming CMB experiments. The small-field sector of mutated hilltop inflation, in principle, can probe up to $r\sim \mathcal{O}(10^{-4})$, resulting in a tensor amplitude consistent with current bounds and potentially detectable by next-generation CMB missions. However, accommodating the high observational value of the scalar spectral index may demand relatively higher e-foldings in mutated hilltop inflation. A key appealing feature of the mutated hilltop inflation model turns out to be its ability to remain consistent with a potential non-detection of primordial gravitational waves by LiteBIRD and/or Simons Observatory.
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Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc

Euclid: From Galaxies to Gravitational Waves – Forecasting Stochastic Gravitational Wave Background Anisotropies and Their Cross-Correlation

K. Z. Yang, G. Cusin, V. Mandic et al. (+141 more)

We estimate the amplitude and spatial anisotropy in the stochastic gravitational wave background (SGWB) energy density due to compact binary coalescence (CBC) events: binary black holes (BBH), binary neutron stars (BNS), and black hole-neutron star (BHNS) mergers. Our starting point is the Flagship Simulation Galaxy Catalogue developed by the Euclid Consortium. For each galaxy in the Catalogue, we use the simulated mass and starformation to constrain the galaxy's star-formation history, and predict its contribution to the gravitational-wave energy density through CBC mergers. Combining such contributions from all galaxies in the Catalogue results in a prediction for the frequency spectrum and spatial anisotropy of the CBC SGWB. We also compare this prediction to semi-analytical models of SGWB generated by compact binaries. We identify a set of effective parameters that capture the key features of these models, and we apply a Bayesian framework to infer these parameters assuming an ideal scenario of cosmic variance-limited search. This represents the first step toward developing a comprehensive framework that will eventually enable the correlation of SGWB anisotropy and Euclid galaxy data, potentially allowing us to extract valuable astrophysical information from this new observable.
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All authors K. Z. Yang, G. Cusin, V. Mandic, C. Scarlata, J. Suresh, B. Altieri, N. Auricchio, C. Baccigalupi, M. Baldi, S. Bardelli, A. Biviano, E. Branchini, M. Brescia, S. Camera, G. Cañas-Herrera, V. Capobianco, C. Carbone, J. Carretero, S. Casas, M. Castellano, G. Castignani, S. Cavuoti, K. C. Chambers, A. Cimatti, C. Colodro-Conde, G. Congedo, L. Conversi, Y. Copin, A. Costille, F. Courbin, H. M. Courtois, H. Degaudenzi, G. De Lucia, H. Dole, F. Dubath, X. Dupac, S. Dusini, S. Escoffier, M. Farina, R. Farinelli, F. Faustini, S. Ferriol, F. Finelli, P. Fosalba, N. Fourmanoit, M. Frailis, E. Franceschi, M. Fumana, S. Galeotta, K. George, B. Gillis, C. Giocoli, P. Gómez-Alvarez, J. Gracia-Carpio, A. Grazian, F. Grupp, S. V. H. Haugan, W. Holmes, F. Hormuth, A. Hornstrup, K. Jahnke, M. Jhabvala, B. Joachimi, E. Keihänen, S. Kermiche, A. Kiessling, B. Kubik, M. Kunz, H. Kurki-Suonio, A. M. C. Le Brun, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, G. Mainetti, D. Maino, O. Mansutti, S. Marcin, O. Marggraf, M. Martinelli, N. Martinet, F. Marulli, E. Medinaceli, S. Mei, Y. Mellier, M. Meneghetti, E. Merlin, G. Meylan, A. Mora, M. Moresco, L. Moscardini, C. Neissner, S.-M. Niemi, C. Padilla, S. Paltani, F. Pasian, K. Pedersen, V. Pettorino, S. Pires, G. Polenta, M. Poncet, L. A. Popa, L. Pozzetti, F. Raison, A. Renzi, J. Rhodes, G. Riccio, E. Romelli, M. Roncarelli, R. Saglia, Z. Sakr, D. Sapone, B. Sartoris, M. Schirmer, P. Schneider, A. Secroun, E. Sefusatti, G. Seidel, S. Serrano, C. Sirignano, G. Sirri, L. Stanco, J. Steinwagner, P. Tallada-Crespí, A. N. Taylor, I. Tereno, N. Tessore, S. Toft, R. Toledo-Moreo, F. Torradeflot, I. Tutusaus, L. Valenziano, J. Valiviita, T. Vassallo, A. Veropalumbo, J. Weller, G. Zamorani, F. M. Zerbi, E. Zucca, T. Castro, J. García-Bellido, V. Scottez, M. Viel, P. Monaco

Astrophysics of Galaxies

Looking at infrared background radiation anisotropies with Spitzer II. Small scale anisotropies and their implications for new and upcoming space surveys

Aidan J. Kaminsky, Alexander Kashlinsky, Richard G. Arendt et al. (+1 more)

Spitzer-based source-subtracted cosmic infrared background (CIB) fluctuations at arcminute-to-degree scales indicate the presence of new populations, whereas sub-arcminute power arises from known $z\lesssim 6$ galaxies. We reconstruct the evolution of the near-IR CIB anisotropies on sub-arcminute scales by known galaxy populations. This method is based on, and significantly advanced over, the empirical reconstruction by \cite{Helgason2012} which is combined with the halo model connecting galaxies to their host dark matter (DM) halos. The modeled CIB fluctuations from known galaxies produce the majority of the observed small-scale signal down to statistical uncertainties of $< 10\%$ and we constrain the evolution of the halo mass regime hosting such galaxies. Thus the large-scale CIB fluctuations from new populations are produced by sources with negligible small-scale power. This appears to conflict with the presented Intra-halo light (IHL) models, but is accounted for if the new sources are at high $z$. Our analysis spanning several Spitzer datasets allows us to narrow the estimated contributions of remaining known galaxies to the CIB anisotropies to be probed potentially from surveys by new and upcoming space missions such as Euclid, SPHEREx, and Roman. Of these, the Roman surveys have the best prospects for measuring the source-subtracted CIB and probing the nature of the underlying new populations at $\lambda <2\ \mu$m, followed by Euclid's surveys, while for SPHEREx the source-subtracted CIB signal from them appears significantly overwhelmed by the CIB from remaining known galaxies.
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All authors Aidan J. Kaminsky, Alexander Kashlinsky, Richard G. Arendt, Nico Cappelluti

Earth and Planetary Astrophysics

A 34.6-day transiting sub-Neptune in the TOI-1422 planetary system

L. Naponiello, P. Leonardi, M. Damasso et al. (+9 more)

TOI-1422 is a G2 V star ($V = 10.6$ mag) known to host a warm Neptune-sized planet, TOI-1422 b, with a mass and radius of about $9M_{\oplus}$ and $4R_{\oplus}$, on a circular orbit with a period of $12.997$ days. An outer planetary candidate in this system had previously been suggested on the basis of a residual signal in the radial velocity (RV) data with a tentative period of $\sim$29 days, along with a possible single transit-like event, although it was not clear at the time whether the two signals belonged to the same companion. In this work, we confirm the presence of a second transiting planet, TOI-1422 c, a sub-Neptune ($R=2.61\pm0.14 R_{\oplus}$) that orbits with a longer period of 34.563 days. This confirmation is based on the detection of three TESS transits, two from newly available sectors, combined with new and archival RV measurements. The sub-Neptune ($\rho_{\rm c}=4.3^{+1.3}_{-1.0}$ g cm$^{-3}$) is more massive than the inner Neptune ($\rho_{\rm b}=0.93^{+0.21}_{-0.20}$ g cm$^{-3}$), having a mass of $M_{\rm c}=14\pm3 M_{\oplus}$, making TOI-1422 a rare anti-ordered system. Furthermore, we detect transit timing variations (TTVs) on the inner planet, with amplitudes of up to 5 hours, suggesting ongoing dynamical interactions. A dynamical analysis that combined TTVs and RVs indicates that planet c alone is unlikely to account for the full TTV amplitude observed on TOI-1422 b. We investigated whether an additional, as yet undetected companion could account for the observed signal, exploring a range of plausible orbital configurations and finding that a low-mass planet located between the two known orbits may be responsible.
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All authors L. Naponiello, P. Leonardi, M. Damasso, M.-L. Steinmeyer, M. Stalport, C. Dorn, A. S. Bonomo, L. Mancini, A. Sozzetti, S. Benatti, S. Colombo, R. Cosentino

Instrumentation and Methods for Astrophysics · Cross-listed from cs.LG

Intrinsic Dimension Estimation for Radio Galaxy Zoo using Diffusion Models

Joan Font-Quer Roset, Devina Mohan and Anna Scaife

In this work, we estimate the intrinsic dimension (iD) of the Radio Galaxy Zoo (RGZ) dataset using a score-based diffusion model. We examine how the iD estimates vary as a function of Bayesian neural network (BNN) energy scores, which measure how similar the radio sources are to the MiraBest subset of the RGZ dataset. We find that out-of-distribution sources exhibit higher iD values, and that the overall iD for RGZ exceeds those typically reported for natural image datasets. Furthermore, we analyse how iD varies across Fanaroff-Riley (FR) morphological classes and as a function of the signal-to-noise ratio (SNR). While no relationship is found between FR I and FR II classes, a weak trend toward higher SNR at lower iD. Future work using the RGZ dataset could make use of the relationship between iD and energy scores to quantitatively study and improve the representations learned by various self-supervised learning algorithms.
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Astrophysics of Galaxies

Planetary nebulae as tracers of stellar population properties: a pilot study with MUSE

Ana Inés Ennis, Johanna Hartke, Fuyan Bian et al. (+4 more)

Planetary nebulae (PNe) are the only single stars in galaxies outside the Local Group that can be used as kinematic tracers of the diffuse light in the extended halo. Analysing their luminosity-specific number density across galaxies of different morphologies has also shown hints that they may be used as tracers of the age and metallicity of stellar populations. A proper understanding of this relation has been hindered by the fact that simultaneously detecting PNe and accurately measuring stellar properties is extremely difficult using classical narrow-band imaging methods, which cannot detect PNe in the bright centres of galaxies. In this work, we use integral-field spectroscopy to overcome this challenge, analysing the inner regions of a sample of ten early-type galaxies from the Extended Planetary Nebulae Survey (ePN.S) for which archival MUSE data was available. With the Diffuse Emission-Line Filter (DELF) technique, we automate the detection of PNe, and perform spectral fitting on the diffuse light to infer kinematics and stellar population parameters. We compare the PN number density profile and its associated alpha-parameter with multiple properties of the host galaxies. We find that our sample follows the previously observationally constrained correlation with the metallicity of the host galaxy. We find a weak anti-correlation between the alpha-parameter and the FUV excess, highlighting the possible relation between the visibility lifetime of PNe on the spectral energy distribution of their host galaxies, with fewer PNe detected in association with stellar populations characterized by a UV excess.
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All authors Ana Inés Ennis, Johanna Hartke, Fuyan Bian, Claudia Pulsoni, Chiara Spiniello, Magda Arnaboldi, Roberto de Propris