arXiv subjects

Pedro Marronetti

Publications and source records attributed to Pedro Marronetti.

At least 19 recordsLinked to original sources

arXiv2026

Universal relations applied to proto-neutron star generated gravitational waves from three-dimensional core collapse supernova simulations

Using asteroseismology techniques, several relations have been developed that relate the quasi-normal, non-radial oscillation mode frequencies of the proto-neutron star (PNS) to the high frequency component of core collapse supernova (CCSN) generated gravitational waves predicted from simulation. These relations are universal in the sense that they are parameterized entirely by PNS properties, e.g., mean density or surface gravity, and are independent of both progenitor properties, e.g., zero age man sequence (ZAMS) mass or metallicity, and the physics included in CCSN simulations, e.g., nuclear equation of state (EOS). In this work, we apply several externally developed universal relations to PNS evolution data--specifically the mass, M, and radius, R,--generated from both two- and three-dimensional CCSN simulations and compare the resulting PNS oscillation frequencies predicted by the universal relations to the peak gravitational wave frequencies computed directly from the simulation-produced spectrogram. Additionally, we use the gravitational wave spectrogram peak frequencies as input to the universal relations and compare the predicted PNS properties from each relation to the true PNS properties as determined by the simulations. In this way, we show what these universal relations would predict for the PNS properties and their evolution from a real CCSN gravitational wave detection in the best case scenario, i.e., no detector noise. Our results indicate that caution must be exercised when using these universal relations, particularly when interpreting their predictions for PNS evolution from a gravitational wave detection, and that, given the extent to which we do see agreement between asteroseismological predictions and simulation outcomes, further development of universal relations would be beneficial.

gr-qc↗

arXiv2025

Gravitational Waves as a Probe of Core Collapse Supernova Progenitor Structure

We present the gravitational wave predictions from two-dimensional core collapse supernova (CCSN) simulations initiated from two nearly identical progenitors that have significantly different internal structures due to their late-stage stellar evolution. At the time of collapse, the 15.78 $M_{\odot}$ and 15.79 $M_{\odot}$ progenitors have compactness parameters $\xi_{2.5}$ of 0.136 and 0.206, respectively. We connect several features of the gravitational wave signal from each model to its previously explored explosion dynamics. In particular, the greater accretion onto the PNS of the more compact model is evident in broad-band frequency features with larger amplitude gravitational wave strains and greater gravitational wave energy release when compared to the less compact model. Additionally, the faster contraction rate of the more compact model is reflected in the $\sim$26% greater slope of the $g$-/$f$-mode feature (gfF) evolution of the gravitational wave signal. This work shows that in principle gravitational wave detection may provide information about interior stellar structure.

astro-ph.HE↗

arXiv2025

Low-Frequency Gravitational Waves in Three-Dimensional Core-Collapse Supernova Models

We discuss the low-frequency gravitational wave signals from three state-of-the-art three-dimensional core-collapse supernova models produced with the \textsc{Chimera} supernova code. We provide a detailed derivation of the gravitational wave signal sourced from the anisotropic emission of neutrinos and provide the total (fluid sourced and neutrino sourced) gravitational waves signal generated in our models. We discuss the templatablity of this low-frequency signal, which is useful for future work involving matched filtering for signal detection and parameter estimation. Errata: The neutrino-induced gravitational waveforms presented were computed incorrectly. They were underestimated by a factor of $4\pi$. While the results are impacted, the original conclusions are not. In fact, they are only reinforced. The corrected versions of Figs. 5--7, 11--16, and 19 are given here. The captions of Figs. 5--7, 11, 12, 16, and 19 are not modified. The captions of Figs. 13, 14, and 15 are corrected to the fit parameters for the corrected waveforms. The corrected versions of Tables I--III are given here. There is no correction to the caption. Finally the authors would like to acknowledge Lella et al. [90] for pointing out the discrepancy between our computed neutrino-induced waveforms and theirs, which prompted us to investigate the discrepancy and which led to the discovery of our error.

astro-ph.HE↗

arXiv2025

Core Collapse Supernova Gravitational Wave Sourcing and Characterization based on Three-Dimensional Models

We present for the first time an analysis of high-frequency gravitational wave (GW) emission from proto-neutron stars (PNS) in core collapse supernovae (CCSN) that combines spatial decomposition and modal decomposition to both source and characterize the emission using three-dimensional CCSN simulations. We analyze simulations initiated from 15 and 25 solar mass progenitors with Solar- and zero-metallicity respectively. We decompose the GW strains into five spatial regions and find that strains are initially largest in the PNS surface layers from accretion and later largest from the Ledoux convective and convective overshoot regions of the PNS. We compute the fractional GW luminosity as a function of enclosed radius and observe that most of the luminosity moves from the PNS surface to deep within the PNS at later times. Using a self-consistent perturbative analysis, we investigate the evolution of the oscillation modes of the PNS. We find that the frequency of the evolving high-frequency component of the GW signal is well matched to the eigenfrequency evolution of the ${}^2g_2$-, ${}^2g_1$-, and ${}^2f$-modes over time. We show that the ${}^2g$-modes emit most of their power in GW initially from the PNS surface region, but within a few 100 ms after bounce, it is the convective overshoot region of the PNS that emits the most GW power for the ${}^2g_1$-mode. Eventually, the ${}^2f$-mode is the dominant mode producing GWs, and they are emitted primarily from the convective overshoot region. Thus, we show that, while the GW emission is global, it is possible to source the dominant contributions to it. We find that the source of the high-frequency GW emission from the PNS in CCSN is more complex than assessed by other methods, as well as time dependent, first emitted by ${}^2g$-modes driven by accretion onto the PNS and later emitted by the ${}^2f$-mode driven by sustained Ledoux convection.

astro-ph.HE↗

arXiv2024

Dependence of the Reconstructed Core-Collapse Supernova Gravitational Wave High-Frequency Feature on the Nuclear Equation of State, in Real Interferometric Data

We present an analysis of gravitational wave (GW) predictions from five two-dimensional Core Collapse Supernova (CCSN) simulations that varied only in the Equation of State (EOS) implemented. The GW signals from these simulations are used to produce spectrograms in the absence of noise, and the emergent high-frequency feature (HFF) is found to differ quantitatively between simulations. Below 1 kHz, the HFF is well approximated by a first-order polynomial in time. The resulting slope was found to vary between 10-50% across all models. Further, using real interferometric noise we investigated the current capabilities of GW detectors to resolve these differences in HFF slope for a Galactic CCSN. We find that for distances up to 1 kpc, current detectors can resolve HFF slopes that vary by at least 30%. For further Galactic distances, current detectors are capable of distinguishing the upper and lower bounds of the HFF slope for groupings of our models that varied in EOS. With the higher sensitivity of future GW detectors, and with improved analysis of the HFF, our ability to resolve properties of the HFF will improve for all Galactic distances. This study shows the potential of using the HFF of CCSN produced GWs to provide insight into the physical processes occurring deep within CCSN during collapse, and in particular its potential to further constrain the EOS through GW detection.

astro-ph.HE↗

arXiv2024

Detecting Gravitational Wave Memory in the Next Galactic Core-Collapse Supernova

We present an approach to detecting (linear) gravitational wave memory in a Galactic core-collapse supernova using current interferometers. Gravitational wave memory is an important prediction of general relativity that has yet to be confirmed. Our approach uses a combination of Linear Prediction Filtering and Matched-Filtering. We present the results of our approach on data from core-collapse supernova simulations that span a range of progenitor mass and metallicity. We are able to detect gravitational wave memory out to 10 kpc. We also present the False Alarm Probabilities assuming an On-Source Window compatible with the presence of a neutrino detection. Errata: The neutrino-induced gravitational waveforms, a component of the total waveforms used to demonstrate the efficacy of the proposed detection method for gravitational wave memory, were computed incorrectly. They were underestimated by a factor of $4\pi$. As a result, the detection results improve and, most important, our primary conclusions are reinforced. In particular, with the corrected waveforms, see Fig. 1 and Fig. 3, the signal for D9.6-3D is in fact detectable at 1 kiloparsec, see Fig. 6 and Fig. 4. The corrected fit parameters are presented in Table 1. The false alarm probability for all three signals is impacted, as shown in Fig. 5. Fig. 5 demonstrates that our proposed method can reliably detect the D9.6-3D signal at 1 kpc for all cutoff values, but our conclusions regarding the inability to detect this signal at 10 and 100 kpc remain the same. We see a boost in the detectability of the D15-3D and D25-3D signals. We now obtain a lower false alarm probability at 10 and 100 kpc. The authors would like to acknowledge Lella et al. [87] for pointing out the discrepancy between our computed neutrino-induced waveforms and theirs, which prompted us to investigate the discrepancy and which led to the discovery of our error.

astro-ph.HE↗

arXiv2022

Core Collapse Supernova Gravitational Wave Emission for Progenitors of 9.6, 15, and 25 Solar Masses

We present gravitational wave emission predictions based on three core collapse supernova simulations corresponding to three different progenitor masses. The masses span a large range, between 9.6 and 25 Solar masses, are all initially non-rotating, and are of two metallicities: zero and Solar. We compute both the temporal evolution of the gravitational wave strains for both the plus and the cross polarizations, as well as their spectral decomposition and characteristic strains.

astro-ph.SR↗

arXiv2020

Gravitational-wave signal of a core-collapse supernova explosion of a 15 Solar mass star

We report on the gravitational wave signal computed in the context of a three-dimensional simulation of a core collapse supernova explosion of a 15 Solar mass star. The simulation was performed with our neutrino hydrodynamics code Chimera. We detail the gravitational wave strains as a function of time, for both polarizations, and discuss their physical origins. We also present the corresponding spectral signatures. Gravitational wave emission in our model has two key features: low-frequency emission (< 200 Hz) emanates from the gain layer as a result of neutrino-driven convection and the SASI and high-frequency emission (> 600 Hz) emanates from the proto-neutron star due to Ledoux convection within it. The high-frequency emission dominates the gravitational wave emission in our model and emanates largely from the convective layer itself, not from the convectively stable layer above it, due to convective overshoot. Moreover, the low-frequency emission emanates from the gain layer itself, not from the proto-neutron star, due to accretion onto it. We provide evidence of the SASI in our model and demonstrate that the peak of our low-frequency gravitational wave emission spectrum corresponds to it. Given its origin in the gain layer, we classify the SASI emission in our model as p-mode emission and assign a purely acoustic origin, not a vortical-acoustic origin, to it. Our dominant proto-neutron star gravitational wave emission is not well characterized by emission from surface g-modes, complicating the relationship between peak frequencies observed and the mass and radius of the proto-neutron star expressed by analytic estimates under the assumption of surface g-mode emission. We present our frequency normalized characteristic strain along with the sensitivity curves of current- and next-generation gravitational wave detectors.

astro-ph.HE↗

arXiv2020

Chimera: A massively parallel code for core-collapse supernova simulation

We provide a detailed description of the Chimera code, a code developed to model core collapse supernovae in multiple spatial dimensions. The core collapse supernova explosion mechanism remains the subject of intense research. Progress to date demonstrates that it involves a complex interplay of neutrino production, transport, and interaction in the stellar core, three-dimensional stellar core fluid dynamics and its associated instabilities, nuclear burning, and the foundational physics of the neutrino-stellar core weak interactions and the equations of state of all stellar core constituents -particularly, the nuclear equation of state associated with nucleons, both free and bound in nuclei. Chimera, by incorporating detailed neutrino transport, realistic neutrino-matter interactions, three-dimensional hydrodynamics, realistic nuclear, leptonic, and photonic equations of state, and a nuclear reaction network, along with other refinements, can be used to study the role of neutrino radiation, hydrodynamic instabilities, and a variety of input physics in the explosion mechanism itself. It can also be used to compute observables such as neutrino signatures, gravitational radiation, and the products of nucleosynthesis associated with core collapse supernovae. The code contains modules for neutrino transport, multidimensional compressible hydrodynamics, nuclear reactions, a variety of neutrino interactions, equations of state, and modules to provide data for post-processing observables such as the products of nucleosynthesis, and gravitational radiation. Chimera is an evolving code, being updated periodically with improved input physics and numerical refinements. We detail here the current version of the code, from which future improvements will stem, which can in turn be described as needed in future publications.

astro-ph.IM↗

arXiv2017

The Gravitational Wave Signal of a Core Collapse Supernova Explosion of a 15M$_\odot$ Star

In this Letter, we report on the gravitational wave signal computed in the context of an $ab$ $initio$, three-dimensional simulation of a core collapse supernova explosion, beginning with a 15M$_\odot$ star and using state-of-the-art weak interactions. The simulation was performed with our neutrino hydrodynamics code Chimera. We discuss the potential for detection of our predicted gravitational signal by the current generation of gravitational wave detectors.

astro-ph.HE↗

arXiv2015

The Development of Explosions in Axisymmetric Ab Initio Core-Collapse Supernova Simulations of 12-25 $M_\odot$ Stars

We present four ab initio axisymmetric core-collapse supernova simulations for 12, 15, 20, and 25 $M_\odot$ progenitors. All of the simulations yield explosions and have been evolved for at least 1.2 seconds after core bounce and 1 second after material first becomes unbound. Simulations were computed with our Chimera code employing spectral neutrino transport, special and general relativistic transport effects, and state-of-the-art neutrino interactions. Continuing the evolution beyond 1 second allows explosions to develop more fully and the processes powering the explosions to become more clearly evident. We compute explosion energy estimates, including the binding energy of the stellar envelope outside the shock, of 0.34, 0.88, 0.38, and 0.70 B ($10^{51}$ ergs) and increasing at 0.03, 0.15, 0.19, and 0.52 B s$^{-1}$, respectively, for the 12, 15, 20, and 25 $M_\odot$ models. Three models developed pronounced prolate shock morphologies, while the 20 $M_\odot$ model, though exhibiting lobes and accretion streams like the other models, develops an approximately spherical, off-center shock as the explosion begins and then becomes moderately prolate $\sim$600 ms after bounce. This reduces the explosion energy relative to the other models by reducing mass accretion during the critical explosion power-up phase. We examine the growth of the explosion energy in our models through detailed analyses of the energy sources and flows. We find that the 12 and 20 $M_\odot$ models have explosion energies comparable to that of the lower range of observed explosion energies while the 15 and 25 $M_\odot$ models are within the range of observed explosion energies, particularly considering the rate at which their explosion energies are increasing. The ejected $^{56}$Ni masses given by our models are all within observational limits as are the proto-neutron star masses and kick velocities. (Truncated)

astro-ph.SR↗

arXiv2015

Multimessengers from 3D Core-Collapse Supernovae

We present gravitational wave and neutrino signatures obtained in our first principle 3D core-collapse supernova simulation of 15M non-rotating progenitor with Chimera code. Observations of neutrinos emitted by the forming neutron star, and gravitational waves, which are produced by hydrodynamic instabilities is the only way to get direct information about the supernova engine. Both GW and neutrino signals show different phases of supernova evolution.

astro-ph.HE↗

arXiv2015

A Neutrino-Driven Core Collapse Supernova Explosion of a 15 M Star

We present results from an ab initio three-dimensional, multi-physics core collapse supernova simulation for the case of a 15 M progenitor. Our simulation includes multi-frequency neutrino transport with state-of-the-art neutrino interactions in the "ray-by-ray" approximation, and approximate general relativity. Our model exhibits a neutrino-driven explosion. The shock radius begins an outward trajectory at approximately 275 ms after bounce, giving the first indication of a developing explosion in the model. The onset of this shock expansion is delayed relative to our two-dimensional counterpart model, which begins at approximately 200 ms after core bounce. At a time of 441 ms after bounce, the angle-averaged shock radius in our three-dimensional model has reached 751 km. Further quantitative analysis of the outcomes in this model must await further development of the post-bounce dynamics and a simulation that will extend well beyond 1 s after stellar core bounce, based on the results for the same progenitor in the context of our two-dimensional, counterpart model. This more complete analysis will determine whether or not the explosion is robust and whether or not observables such as the explosion energy, 56Ni mass, etc. are in agreement with observations. Nonetheless, the onset of explosion in our ab initio three-dimensional multi-physics model with multi-frequency neutrino transport and general relativity is encouraging.

astro-ph.SR↗

arXiv2015

Three-dimensional core-collapse supernova simulated using a 15 $M_\odot$ progenitor

We have performed ab initio neutrino radiation hydrodynamics simulations in three and two spatial dimensions (3D and 2D) of core-collapse supernovae from the same 15 $M_\odot$ progenitor through 440 ms after core bounce. Both 3D and 2D models achieve explosions, however, the onset of explosion (shock revival) is delayed by $\sim$100 ms in 3D relative to the 2D counterpart and the growth of the diagnostic explosion energy is slower. This is consistent with previously reported 3D simulations utilizing iron-core progenitors with dense mantles. In the $\sim$100 ms before the onset of explosion, diagnostics of neutrino heating and turbulent kinetic energy favor earlier explosion in 2D. During the delay, the angular scale of convective plumes reaching the shock surface grows and explosion in 3D is ultimately lead by a single, large-angle plume, giving the expanding shock a directional orientation not dissimilar from those imposed by axial symmetry in 2D simulations. We posit that shock revival and explosion in the 3D simulation may be delayed until sufficiently large plumes form, whereas such plumes form more rapidly in 2D, permitting earlier explosions.

astro-ph.SR↗

arXiv2015

Gravitational Wave Signatures of Ab Initio Two-Dimensional Core Collapse Supernova Explosion Models for 12-25 Solar Masses Stars

We present the gravitational waveforms computed in ab initio two-dimensional core collapse supernova models evolved with the Chimera code for progenitor masses between 12 and 25 solar masses. All models employ multi-frequency neutrino transport in the ray-by-ray approximation, state-of-the-art weak interaction physics, relativistic transport corrections such as the gravitational redshift of neutrinos, two-dimensional hydrodynamics with the commensurate relativistic corrections, Newtonian self-gravity with a general relativistic monopole correction, and the Lattimer-Swesty equation of state with 220 MeV compressibility, and begin with the most recent Woosley-Heger nonrotating progenitors in this mass range. All of our models exhibit robust explosions. Therefore, our waveforms capture all stages of supernova development: 1) a relatively short and weak prompt signal, 2) a quiescent stage, 3) a strong signal due to convection and SASI activity, 4) termination of active accretion onto the proto-neutron star, and 5) a slowly increasing tail that reaches a saturation value. Fourier decomposition shows that the gravitational wave signals we predict should be observable by AdvLIGO for Galactic events across the range of progenitors considered here. The fundamental limitation of these models is in their imposition of axisymmetry. Further progress will require counterpart three-dimensional models, which are underway.

astro-ph.HE↗

arXiv2015

Recent Progress on Ascertaining the Core Collapse Supernova Explosion Mechanism

We have been working within the fundamental paradigm that core collapse supernovae (CCSNe) may be neutrino driven, since the first suggestion of this by Colgate and White nearly five decades ago. Computational models have become increasingly sophisticated, first in one spatial dimension assuming spherical symmetry, then in two spatial dimensions assuming axisymmetry, and now in three spatial dimensions with no imposed symmetries. The increase in the number of spatial dimensions has been accompanied by an increase in the physics included in the models, and an increase in the sophistication with which this physics has been modeled. Computation has played an essential role in the development of CCSN theory, not simply for the obvious reason that such multidimensional, multi-physics, nonlinear events cannot possibly be fully captured analytically, but for its role in discovery. In particular, the discovery of the standing accretion shock instability (SASI) through computation about a decade ago has impacted all simulations performed since then. Today, we appear to be at a threshold, where neutrinos, neutrino-driven convection, and the SASI, working together over time scales significantly longer than had been anticipated in the past, are able to generate explosions, and in some cases, robust explosions, in a number of axisymmetric models. But how will this play out in three dimensions? Early results from the first three-dimensional (3D), multi-physics simulation of the "Oak Ridge" group are promising. I will discuss the essential components of today's models and the requirements of realistic CCSN modeling, present results from our one-, two-, and three-dimensional models, place our models in context with respect to other efforts around the world, and discuss short- and long-term next steps.

astro-ph.SR↗

arXiv2014

Advancing Nucleosynthesis in Self-consistent, Multidimensional Models of Core-Collapse Supernovae

We investigate core-collapse supernova (CCSN) nucleosynthesis in polar axisymmetric simulations using the multidimensional radiation hydrodynamics code CHIMERA. Computational costs have traditionally constrained the evolution of the nuclear composition in CCSN models to, at best, a 14-species $α$-network. Such a simplified network limits the ability to accurately evolve detailed composition, neutronization and the nuclear energy generation rate. Lagrangian tracer particles are commonly used to extend the nuclear network evolution by incorporating more realistic networks in post-processing nucleosynthesis calculations. Limitations such as poor spatial resolution of the tracer particles, estimation of the expansion timescales, and determination of the "mass-cut" at the end of the simulation impose uncertainties inherent to this approach. We present a detailed analysis of the impact of these uncertainties on post-processing nucleosynthesis calculations and implications for future models.

astro-ph.SR↗

arXiv2014

Two- and Three-Dimensional Multi-Physics Simulations of Core Collapse Supernovae: A Brief Status Report and Summary of Results from the "Oak Ridge" Group

We summarize the results of core collapse supernova theory from one-, two-, and three-dimensional models and provide a snapshot of the field at this time. We also present results from the "Oak Ridge" group in this context. Studies in both one and two spatial dimensions define the necessary} physics that must be included in core collapse supernova models: a general relativistic treatment of gravity (at least an approximate one), spectral neutrino transport, including relativistic effects such as gravitational redshift, and a complete set of neutrino weak interactions that includes state-of-the-art electron capture on nuclei and energy-exchanging scattering on electrons and nucleons. Whether or not the necessarily approximate treatment of this physics in current models that include it is sufficient remains to be determined in the context of future models that remove the approximations. We summarize the results of the Oak Ridge group's two-dimensional supernova models. In particular, we demonstrate that robust neutrino-driven explosions can be obtained. We also demonstrate that our predictions of the explosion energies and remnant neutron star masses are in agreement with observations, although a much larger number of models must be developed before more confident conclusions can be made. We provide preliminary results from our ongoing three dimensional model with the same physics. Finally, we speculate on future outcomes and directions.

astro-ph.SR↗