arXiv subjects

Marco Cusinato

Publications and source records attributed to Marco Cusinato.

6 recordsLinked to original sources

arXiv2026

The impact of nuclear equations of state on the dynamics and multi-messenger emission of magnetorotational stellar explosions

The gravitational collapse of massive stars at the end of their life leads to powerful supernova explosions that produce compact objects, regulate the dynamics of host galaxies, and contribute to cosmic chemical evolution. In the presence of fast rotation and strong magnetic fields, such explosions can reach extreme energies, explaining sources such as hypernovae and long gamma-ray bursts. We investigate the impact of variations in the nuclear equation of state (EoS) on magnetorotational explosions and their multimessenger emission, including neutrinos and gravitational waves. Differences in stiffness, composition, and finite-temperature behavior of the EoS affect the collapse, bounce, and jet-launching phases. Using the Aenus-Alcar code, which includes relativistic magnetohydrodynamics, two-moment neutrino transport, neutrino-matter interactions, and general-relativistic corrections, we perform axisymmetric simulations with different EoSs. All models start from the same pre-supernova progenitor with solar metallicity, a zero-age main sequence mass of 20 solar masses, a dipolar magnetic field, and a shellular rotation profile. The different EoSs produce significant variations in explosion dynamics, proto-neutron star properties, ejecta mass, and multimessenger signals. Our results show that magnetorotational core-collapse supernova signatures depend not only on the cold stiffness of the EoS, but also on its thermal and compositional properties, highlighting the importance of combining gravitational-wave and neutrino observations to constrain dense matter physics and the explosion mechanism.

astro-ph.HE↗

arXiv2026

Impact of the equation of state on core collapse supernovae I: the low-$T/|W|$ instability

Rapidly rotating core-collapse supernovae are promising sources of multimessenger emission, as non-axisymmetric dynamics in the newly formed proto-neutron star can leave characteristic imprints on both gravitational waves and neutrinos. We present three-dimensional neutrino-magnetohydrodynamics simulations of the collapse of a rapidly rotating $35\,\mathrm{M}_\odot$ progenitor, performed with five different finite-temperature nuclear equations of state, to investigate how dense-matter physics affects the development of the low-$T/|W|$ instability and its associated multimessenger signatures. We find that the low-$T/|W|$ instability develops in all equation of state models considered, indicating that its occurrence is robust for this rapidly rotating progenitor. However, its onset time, dominant azimuthal structure, lifetime, and characteristic multimessenger frequencies vary among models, reflecting differences in the evolving proto-neutron star structure and rotation profile. The instability produces large-scale spiral modes that generate quasi-periodic gravitational wave emission and modulate the neutrino luminosities, especially along directions close to the equatorial plane. The dominant gravitational wave frequency associated with the instability correlates with the effective stiffness and compactness of the proto-neutron star: models with more compact/stiffer configurations emit at higher frequencies. This suggests that, in rapidly rotating core-collapse supernovae, the frequency of the low-$T/|W|$ instability-driven gravitational wave signal may provide a diagnostic of the dense-matter equation of state, complementary to the information carried by the neutrino signal.

astro-ph.HE↗

arXiv2025

Convection signatures in early-time gravitational waves from core-collapse supernovae

Gravitational waves emitted from core-collapse supernova explosions are critical observables for extracting information about the dynamics and properties of both the progenitor and the post-bounce~evolution of the system. They are prime targets for current interferometric searches and represent a key milestone for the capabilities of next-generation interferometers. This study aims to characterize how the gravitational waveform associated with prompt stellar convection depends on the rotational rate and magnetic field topology of the progenitor star. We carry out a series of axisymmetric simulations of a $16.5\,\mathrm{M}_\odot$ red supergiant with five configurations of initial magnetic fields and varying degrees of initial rotation. We then analyze the contribution of early-time convection and the proto-neutron star core to the waveform using ensemble empirical mode decomposition, alongside spectral and Fourier analyses, to facilitate comparison and interpretation of the results. Our simulations reveal that early post-bounce gravitational waves signals are dominated by the first six intrinsic mode functions, with variations due to rotation and magnetic fields influencing the signal strength. Strong magnetic fields decelerate core rotation, affecting mode excitation. Regardless of the initial rotation, convection consistently drives a low-frequency mode that lasts throughout the evolution. Additionally, our results show that the bounce signal is not consistently the strongest component of the waveform. Instead, we find that prompt convection generates a post-bounce signal of comparable or even greater amplitude.

astro-ph.HE↗

arXiv2025

Resonant amplification of multimessenger emission in rotating stellar core collapse

In a series of axisymmetric core-collapse supernova simulations extending up to $\sim 2\,\mathrm{s}$, we identify a regime of pre-collapse central rotation rates ($\sim 1\,\mathrm{Hz}$) that greatly enhances the emission of gravitational waves (GWs) during extended periods of time after bounce. The enhancement is a consequence of the resonance between the frequency of the fundamental quadrupolar $^2f$-mode of oscillation of the proto-neutron star and the frequency of the epicyclic oscillations at the boundary of the inner core. We observe periods of about several hundred milliseconds each where the resonance is active. The GW emission enhancement produces a correlated resonant modulation of the associated neutrino signal at the same frequencies. With GW frequencies of $\mathcal{O}(1\,\mathrm{kHz})$ and strain amplitudes within the sensitivity curves of current and next-generation interferometers at distances of $\mathcal{O}(1\,\mathrm{Mpc})$, this resonant-amplification mechanism may represent a potential game-changer for unveiling the supernova explosion mechanism through multimessenger astronomy.

astro-ph.HE↗

arXiv2024

Efficient Stochastic Template Bank using Inner Product Inequalities

Gravitational wave searches are crucial for studying compact sources like neutron stars and black holes. Many sensitive modeled searches use matched filtering to compare gravitational strain data to a set of waveform models known as template banks. We introduce a new stochastic placement method for constructing template banks, offering efficiency and flexibility to handle arbitrary parameter spaces, including orbital eccentricity, tidal deformability, and other extrinsic parameters. This method can be computationally limited by the ability to compare proposal templates with the accepted templates in the bank. To alleviate this computational load, we introduce the use of inner product inequalities to reduce the number of required comparisons. We also introduce a novel application of Gaussian Kernel Density Estimation to enhance waveform coverage in sparser regions. Our approach has been employed to search for eccentric binary neutron stars, low-mass neutron stars, primordial black holes, supermassive black hole binaries. We demonstrate that our method produces self-consistent banks that recover the required minimum fraction of signals. For common parameter spaces, our method shows comparable computational performance and similar template bank sizes to geometric placement methods and stochastic methods, while easily extending to higher-dimensional problems. The time to run a search exceeds the time to generate the bank by a factor of $\mathcal{O}(10^5)$ for dedicated template banks, such as geometric, mass-only stochastic, and aligned spin cases, $\mathcal{O}(10^4)$ for eccentric and $\mathcal{O}(10^3)$ for the tidal deformable bank. With the advent of efficient template bank generation, the primary area for improvement is developing more efficient search methodologies.

astro-ph.HE↗

arXiv2022

Neutrino emission from binary neutron star mergers: characterizing light curves and mean energies

Neutrinos are copiously emitted by neutron star mergers, due to the high temperatures reached by dense matter during the merger and its aftermath. Neutrinos influence the merger dynamics and shape the properties of the ejecta, including the resulting $r$-process nucleosynthesis and kilonova emission. In this work, we analyze neutrino emission from a large sample of merger radiation hydrodynamics simulations in Numerical Relativity, covering a broad range of initial masses, nuclear equation of state and viscosity treatments. We extract neutrino luminosities and mean energies, and compute quantities of interest such as the peak values, peak broadnesses, time averages and decrease time scales. We provide a systematic description of such quantities, including their dependence on the initial parameters of the system. We find that for equal-mass systems the total neutrino luminosity (several $10^{53}{\rm erg~s^{-1}}$) decreases for increasing reduced tidal deformability, as a consequence of the less violent merger dynamics. Similarly, tidal disruption in asymmetric mergers leads to systematically smaller luminosities. Peak luminosities can be twice as large as the average ones. Electron antineutrino luminosities dominate (initially by a factor of 2-3) over electron neutrino ones, while electron neutrinos and heavy flavour neutrinos have similar luminosities. Mean energies are nearly constant in time and independent on the binary parameters. Their values reflect the different decoupling temperature inside the merger remnant. Despite present uncertainties in neutrino modelling, our results provide a broad and physically grounded characterization of neutrino emission, and they can serve as a reference point to develop more sophisticated neutrino transport schemes.

astro-ph.HE↗