ECT*-EMMI/GSI workshop: The interplay of magnetic fields, nuclear physics, and nucleosynthesis in neutron-star mergers and supernovae

Sep 21, 2026, 9:00 AM → Sep 25, 2026, 7:00 PM Europe/Rome

Aula Renzo Leonardi (ECT*)

Almudena Arcones, Evan O'Connor, Philipp Mösta, Sanjana Curtis

ECT*-EMMI/GSI workshop

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Neutron-star mergers and core-collapse supernovae are among the most promising sites for the synthesis of heavy elements in the universe. These astrophysical phenomena bring together a rich interplay of general relativity, neutrino physics, nuclear reactions, and magneto-hydrodynamics (MHD). Among these factors, magnetic fields are increasingly recognized as playing a pivotal role in shaping the dynamics and nucleosynthetic outcomes of these events. Recent observational breakthroughs, from the detection of gravitational waves (e.g., GW170817) with EM counterparts and increasingly detailed supernova spectra, demand a deeper theoretical understanding of how magnetic fields interact with nuclear physics and influence heavy-element nucleosynthesis. At the same time, simulations of these events now routinely include magnetic fields and detailed neutrino transport demonstrating the potential of magneto-rotational supernovae and neutron-star mergers to produce rich nucleosynthesis yields including the heaviest elements produced by the r-process and set the stage for GRB jets. Given all these recent developments we are at a critical moment to advance the field but there is a need for detailed discussions and interactions among nuclear physicists, astrophysicists, and computational modelers to address key open questions and make the most of the available observational datasets and computational resources. This workshop aims to bring these communities together.

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Supporting institutions

           

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Poster_TheInterplay.pdf

Mon, September 21

1 Collapse and nucleosynthesis of magnetized massive stars and white dwarfs

Speaker: Takami Kuroda (Max Planck Institute for Gravitational Physics)

2 Impact of rotation and magnetic fields on core-collapse supernovae

Speaker: Martin Obergaulinger (Universitat de València)

3 Magnetic Fields, Turbulence, and Vorticity in CCSN Simulations

Speaker: Carla Frohlich (North Carolina State University, United States)

10:30 AM Coffee

4 Three-dimensional Core-collapse Supernova Progenitors

Asymmetries induced by turbulent convection during late-stage stellar burning can be critical for the outcome of supernova simulations. I will present results from five three-dimensional burning simulations and discuss how the progenitor asymmetries influence the subsequent core-collapse and explosion.

Speaker: Haakon Andresen (Stockholm University)

5 Magnetized & Rotating 3D Core Collapse Supernova Progenitors

There are few three dimensional simluations exploring how magnetic fields influence pre-collapse structure and rotation in core collapse supernovae. I will present some preliminary results from a study varying magnetic field geometry in a rotating three dimensional progenitor model, discussing how they compare to previous work and what we can do with them in the future.

Speaker: Maria Mutz (University of Arizona)

6 Magnetic fields, dissipation, and multimessenger signatures in three-dimensional core-collapse supernova simulations

Rapid rotation and strong magnetic fields can reshape the dynamics, energetics, and multimessenger emission of core-collapse supernovae. We investigate these effects using three-dimensional magnetohydrodynamic simulations together with hydrodynamic control models.

Rotation alone modifies the protoneutron star structure, neutrino emission, post-shock dynamics, and the development of non-axisymmetric instabilities. Magnetic fields can alter this evolution further by redistributing angular momentum, extracting free energy from differential rotation, and reorganizing the flow into magnetically influenced outflows. These effects are reflected in the gravitational wave signal through rotational dynamics, protoneutron star oscillations, and large-scale asymmetries, while the neutrino signal traces changes in accretion geometry and remnant structure.

Interpreting these physical and multimessenger signatures also requires understanding how magnetic energy is processed within the simulations. Energy budget diagnostics suggest that part of the extracted magnetic energy is neither retained in the resolved magnetic field nor accounted for by the resolved channels of magnetic energy conversion and transport through Lorentz work and Poynting flux, but instead appears in a dissipation-like residual. Determining whether this residual reflects unresolved reconnection, numerical diffusion, or both is important for assessing magnetic field saturation, outflow power, energy conversion efficiency, and the connection between rotational energy loss and explosion energetics. We discuss how this uncertainty may affect the physical interpretation of the overall dynamics and the multimessenger predictions of global magnetorotational supernova simulations.

12:00 PM Lunch

7 Opening

Speaker: ECT* Director

8 Simulations of MHD CCSN Explosions

Speakers: Jennifer Quinlan (Monash University), Jennifer Quinlan (Monash University)

9 Gravitational waves from magnetorotational supernovae

Speaker: Shota Shibagaki (Wrocław University of Science and Technology)

10 Multimessenger Probes of Rotation in Magnetized Core-Collapse Supernovae

Speaker: Pravita Hallur (NIKHEF)

11 Session Q&A/transition

3:30 PM Coffee

12 Discussion

Speakers: Carla Frohlich (North Carolina State University, United States), Haakon Andresen (Stockholm University)

Tue, September 22

13 Overview

Speaker: Sebastiano Bernuzzi (FSU Jena)

14 A first-principles binary neutron star merger model of GW170817, GRB170817A, and AT2017gfo

Speaker: Kenta Kiuchi (Max Planck Institute for Gravitational Physics)

ECTs2026.pdf

15 Neutrinos in neutron star merger simulations

I will review the role of neutrinos in neutron star mergers, the impact of individual reactions, and the current state of modeling for neutrino transport and neutrino-matter interactions.

Speaker: Francois Foucart (University of New Hampshire)

Foucart.pptx

10:30 AM Coffee

16 The Role of Neutrino Transport in Delayed Collapse Binary Neutron Star Merger Remnants

We investigate the impact of neutrino transport on delayed-collapse binary neutron-star merger remnants using general-relativistic magnetohydrodynamic (GRMHD) simulations. We compare two simulations with identical initial conditions, one employing grey, three-species M1 neutrino transport and the other neglecting neutrino radiation. Neutrino cooling advances black-hole formation and produces a cooler torus, while irradiation increases the electron fraction of the polar material. The neutrino-free model develops a larger magnetic-energy reservoir and a stronger late-time, baryon-loaded outflow. By following the evolution through collapse and into the black-hole–torus phase, we examine how neutrino cooling and irradiation influence magnetic-field amplification and the emergence of a magnetic breakout from the torus

Speaker: Marie Cassing (Goethe University Frankfurt)

17 Beyond npe matter in binary neutron star mergers

Speaker: Peter Hammond (Albert Einstein Institute)

18 Full-GR resistive MHD simulations of core collapse supernovae and neutron star mergers on GPUs

In this talk, I will present a new resistive-MHD module that I have implemented within the GPU-accelerated GRMHD code GRaM-X. This module enables fully general-relativistic resistive-MHD simulations of core-collapse supernovae and binary neutron star mergers on GPUs, using a finite-temperature microphysical equation of state and M0 neutrino transport.

I will first briefly introduce the resistive-MHD implementation and present a selection of code tests used to validate the new module. I will then present results from a proof-of-concept simulation of a rapidly rotating, strongly magnetized core-collapse supernova. In this simulation, I use a finite but high electrical conductivity, and the resulting dynamics lead to the formation of a jet.

Finally, I will discuss preliminary results from a second proof-of-concept simulation of a non-spinning, magnetized 1.3–1.3 (M_\odot) binary neutron star merger using the DD2 equation of state and the new resistive-MHD module. This part of the work is ongoing, and I will highlight some of the initial results and challenges encountered so far.

Speaker: Sara Azizi (University of Amsterdam)

12:00 PM Lunch

19 Towards Realistic Electromagnetic Counterpart Modeling of Binary Neutron Binary Mergers

Speaker: Kyohei Kawaguchi (Max-Planck-Institut für Gravitationsphysik)

20 Magnetic disks around prompt-collapse black holes from binary neutron star mergers

Speaker: Ricard Aguilera Miret (Hamburg Universität)

21 GRACE: An Open-Source Framework for GPU-Accelerated Numerical Relativity

Speaker: Carlo Musolino (Max Planck Institute for Gravitational Physics (Albert Einstein Institute))

22 Neural Network Emulator for M1 Neutrino Reaction Rates in Binary Neutron Star Merger

We present a neural network emulator for the bns_nurates library, which computes neutrino reaction rates used in neutrino transport in binary neutron star merger simulations. We find that the emulator reproduces the opacities to within a few percents across the relevant thermodynamic conditions and accelerates their evaluation by roughly an order of magnitude. When deployed in a global \athenak binary neutron star merger simulation, it recovers the remnant structure, neutrino luminosities, and ejecta composition of a reference run using the full \nurates library, at a factor-of-two lower overall cost.

Speaker: Yi Qiu (Pennsylvania State University)

3:30 PM Coffee

23 Discussion

Speakers: Albino Perego (University of Trento, Italy), Smaranika Banerjee (Oxford Unicersity)

Wed, September 23

24 Gamma rays, neutrino flavor transformation and other physics relevant for element synthesis

Speaker: Gail McLaughlin (North Carolina State University)

25 Telling the difference between ECSN and CCSN

With ECSN, if they occur, likely being classified observationally as Type IIp, we are left in need of observable clues that will let us separate ECSN from their low mass CCSN counterparts. Details in the nucleosynthesis are likely to provide the best such clues. However, there are among the lightest CCSN, a class of ECSN mimics with which we must content. We will discuss these possibilities in the light of the results of multi-dimensional simulations for ECSN and CCSN, including the ECSN mimics.

Speaker: William Raphael Hix (Oak Ridge National Laboratory / Univ. of Tennessee)

Hix_ECT_0926.pdf

26 Overview of Observational and Theoretical Constraints on Neutron Stars and the EOS

Looking back on the old Rhoades & Ruffini estimate for the neutron star maximum mass based on GR and causality, I further develop their control cheory argument to establish absolute maximum and minimum bounds to neutron star radii, moments of inertia, binding energies and tidal deformabilities as functions of central energy density (or, equivalently, mass). These bounds are compared to recent observational inferences from X-ray observations of rapidly rotating neutron stars, gravitational radiation from neutron star mergers, pulsar timing studies, and quasi-periodic oscillations seen in a few short gamma-ray busts. A new method is proposed for inferring the dense matter EOS from observations that may sharply reduce systematic biases from prior uncertainties inherent in traditional Bayesian methods that can be as large as observational uncertainties.

Speaker: James Lattimer (Stony Brook University)

10:30 AM Coffee

27 Impact of stellar evolution phenomena on supernova explosion and nucleosynthesis

Speaker: Luca Boccioli (TU Darmstadt)

28 Finite-temperature ab-initio-Informed Nuclear Equation-of-State Tables (FINEST): Nuclear matter uncertainties in core-collapse supernovae

Speaker: Finia Jost (TU Darmstadt)

29 Nucleosynthesis in Core-Collapse Supernova Simulations of Binary-Star Progenitors

Binary interaction is common amongst massive stars and can affect their structure and composition significantly. This has
important implications for the nucleosynthetic yields and observables connecting theory and observation. However, binary-
evolved progenitors remain largely unexplored in modern neutrino-driven core-collapse supernova simulations. We
performed one- and two-dimensional core-collapse supernova simulations of single- and binary-star progenitors in which we investigate
the impact of binary interaction on the explosion and examine the effect of in-situ networks on the dynamics and resulting
nucleosynthesis relative to post-processing approaches. Our progenitors highlight the impact of binary interaction on the pre-
supernova core structure of the star and its significance for explodability. In accordance with previous studies, we find that binary
progenitors are generally more explodable than single stars with the same initial mass, indicating that the supernova outcome
cannot be well correlated with the initial mass of the star. We find that energy generation from nuclear reactions, as well as
the abundances of key isotopes such as Ni56, can be well captured by a small 𝛼-chain network. In contrast, there are notable
discrepancies in the production of Ti, Cr, and Fe isotopes which remain sensitive to the network size and thermodynamic history.

Speaker: Gaétan Jalin (TU Darmstadt)

12:00 PM Lunch

30 Outer crust of cold, strongly magnetized neutron stars

Speaker: Juliette Servais (Université libre de Bruxelles)

31 Role of Fast Neutrino Flavor Conversion in Core-collapse Supernovae with the Boltzmann Neutrino Transport

Speaker: Ryuichiro Akaho (Waseda University)

32 Strong magnetic fields and light clusters in warm stellar matter

Speaker: Luigi Scurto (Laboratori Nazionali del Sud, INFN)

33 Protoneutron star asteroseismology and universality in supernova gravitational waves

Speaker: hajime sotani (Kochi University)

20260923-ETC*.pdf

34 Session Q&A/transition

3:30 PM Coffee

35 Gravitational Waves from Long-Term Axisymmetric Simulations of Accretion-Induced Collapse of White Dwarfs

Speaker: Jinhao Cai (Max-Planck-Institute for Astrophysics)

36 Discussion

Thu, September 24

37 Disk Outflows in Neutron Star Mergers and Collapsars

Speaker: Rodrigo Fernandez (University of Alberta)

38 Accretion, nucleosynthesis, dynamos and jets in mergers and extreme supernovae

Speaker: Daniel Siegel

ECT_Trento_Sep2026.pdf

39 Postmerger Disk Ejecta and Heavy Element Nucleosynthesis

Speaker: Dr Kelsey Lund (UC Berkeley)

10:30 AM Coffee

40 The Influence of Magnetic Fields and Trapped Neutrinos on the Prompt Collapse Dynamics of Neutron Star Mergers

Speaker: Raffaele Ferrari (University of Trento)

41 Small-scale and mean-field dynamics in accretion disks around rapidly rotating neutron stars

Speaker: Michael Müller (University of Greifswald)

42 Nucleosynthesis in Outflows from Neutrino-Cooled Accretion Disks Around Black Holes

Speaker: Javiera Hernández Morales (University of Greifswald)

12:00 PM Lunch

43 Complex magnetic fields and nuclear EoS in extreme core-collapse supernovae

Speaker: Matteo Bugli (CEA-Saclay)

44 From Early Light to late Nebular Emission: Modelling Neutron Star Merger Signals

Overview

Speaker: Smaranika Banerjee (Oxford Unicersity)

45 Binary Neutron Star Mergers with M1 Neutrino Transport: Dynamics and Ejecta

Speaker: Ruocheng Zhai (The Pennsylvania State University)

46 End-to-End Modeling of Kilonovae from Binary Neutron Star Mergers

Speaker: Lieke Sippens Groenewegen (Monash University)

3:40 PM Coffee

47 Magnetar Imprints in Neutron Star Mergers

Speaker: Quentin Pognan (Max Planck Institute for Gravitational Physics (Albert Einstein Institute))

48 Discussion

Fri, September 25

49 Hyperaccreting Neutron Stars inside Massive Envelopes

Speaker: Patrick Chi-Kit Cheong (University of New Hampshire)

50 r-process Nucleosynthesis and Kilonova Emission from the Induced Collapse of White Dwarfs

Accretion-induced collapse (AIC) of white dwarfs provides a promising astrophysical site for r-process nucleosynthesis and kilonova emission. Drawing on results from multidimensional GRMHD and radiative transfer simulations, my talk will explore the conditions that favor robust heavy element production and discuss the electromagnetic signature of these rare and intriguing events.

Speaker: Tetyana Pitik (UC Berkeley)

51 Session Q&A/transition

10:30 AM Coffee

52 Discussion&Closeout

12:00 PM Lunch