The behavior of neutrinos in core-collapse supernovae is very different from their usual role as ephemeral larcenists. Neutrinos are the principle mechanism by which energy and lepton number are transported within the explosion, while core-collapse supernovae produce neutrinos in such prodigious quantities that the neutrino signal from a supernova in The Galaxy would allow us to directly...
Neutrinos play a critical role of transporting energy and changing the lepton density within core-collapse supernovae (CCSNe) and neutron star mergers. The possibility of flavor or angular instabilities in the neutrino distributions have the potential to revolutionize our understanding of the CCSN explosion mechanism and neutrino signals. However, understanding these effects will require...
We present the new code NADA-FLD to solve multi-dimensional neutrino-hydrodynamics in full general relativity (GR) in spherical polar coordinates. The neutrino transport assumes the flux-limited diffusion (FLD) approximation and evolves the neutrino energy densities measured in the frame comoving with the fluid. Operator splitting is used to avoid multi-dimensional coupling of grid cells in...
At the present time even the most sophisticated, multi-dimensional simulations of core-collapse supernovae do not (self-consistently) include neutrino flavor transformation. This physics is missing despite the importance of neutrinos in the core-collapse explosion paradigm. Because of this dependence, any flavor transformation that occurs in the region between the proto-neutron star and the...
Neutrinos are the main vector of energy transport in the revival process of a stalled supernova shock. The treatment of their interactions with the medium is therefore an important part of our simulations. One of those interactions is the nucleon-nucleon bremsstrahlung which will create or annihilate a neutrino/anti-neutrino pair. In this talk, I will present the results for a finer treatment...
Simulations of Core-Collapse Supernovae rely on four important ingredients: An efficient and reasonably accurate implementation of equation of state and reaction rates, a spatially and temporally well-resolved evolution of shock-roof magneto-hydrodynamics, a multidimensional parallel implementation of neutrino transport approximations with a well-defined pinch of relativistic effects and...
Using Fornax, we have provided a broad suite of almost a dozen high-fidelity 3D simulations of core-collapse supernovae, spanning 9 $-$ 60 M$_{\odot}$ in progenitor mass. Such a plethora of simulations, many through one second postbounce, allows us to probe the detailed dependence of explosion outcome on progenitor profile, grid resolution, and neutrino microphysics as well as study emergent...
We will report fully relativistic CCSN simulations of 20Msun progenitor star with M1 neutrino transport. To explore the role of magnetic field, particularly in the explosion dynamics and in the explosive nucleosynthesis, we calculated several models w/ and w/o rotation and magnetic field. Regarding the dynamics, we found a bipolar outflow in strongly magnetized model, while oblate like...
In this talk, I would like to report the recent results of the multi-dimensional core-collapse simulations with the Boltzmann-radiation-hydrodynamics code, which solves the Boltzmann equations for neutrino transport directly. The neutrino transport is an important ingredient of the core-collapse supernova (CCSN) simulations since the neutrino heating plays a crucial role in the explosion...
Numerical simulations of core collapse supernovae (CCSNe) must balance numerical accuracy with computational cost in order to produce numerous, high-fidelity simulations. The FLASH code architecture leverages advanced neutrino treatments and a general relativistic effective potential (GREP) to efficiently simulate CCSNe. These explosive, high energy events are prolific sources of...
The detection of 1.5-3.2 Myr 60-Fe on Earth indicates recent nearby core-collapse supernovae.
For supernovae in multiple stars, the primary stars become neutron stars, while former
companions can get unbound (runaway stars). By tracing back the space motion of runaway
and neutron stars to the nearest young (about 16 Myr) association of massive stars
(Scorpius-Centaurus-Lupus), we found...
1) A unusually strong radial magnetic field detected near our Galactic Center (2013) is consistent with the prediction from our model of supermassive object with magnetic monopoles (MM) ( Peng and Chou 2001). The important implications of the unusually strong radial magnetic field near the GC are: a) A strong evidence of the existence of MM; b) The black hole model of the suppermassive...
The equation of state (EoS) of dense hadronic matter is of crucial importance for the description of the static and dynamical properties of neutron stars. In this talk I will review the current status of the hadronic EoS for neutron stars, from the point of both ab-initio many-body approaches and phenomenological models. The theoretical predictions for the hadronic EoS will be compared to the...
Uncertainties in our knowledge of the properties of dense matter near and above nuclear saturation density are among the main sources of variations in multi-messenger signatures predicted for the core collapse of massive stars and the properties of the resulting remnants. In this talk, I discuss how variations in the equation of state of dense matter affect the core collapse of massive stars....
I would like to report the recent progress on microphysics and supernova neutrinos utilizing our numerical simulations based on Boltzmann equation. As recent progress of core-collapse supernova simulations is rapid toward the first principle type calculations, remaining uncertainties of the microphysics are becoming important.
We have been developing the data table of equation of state...
Core-collapse supernovae (CCSN) are cosmic laboratories for physics at the extremes and numerical simulations are essential to help us understand the underlying mechanisms in these events. A key ingredient in simulations is the equation of state (EOS), which determines the contraction behavior of the proto-neutron star (PNS) and thus impacts neutrino energies and explosion dynamics. However,...
The aim of our work is to develop a unified equation of state (EoS) for nuclear and quark matter for a wide range in temperature, baryon density and iso-spin asymmetry, which will make it applicable for heavy-ion collisions as well as for the astrophysics of neutron stars, neutron-star mergers and supernova explosions.
As a first step, we use improved EoS for the hadronic and quark matter...
Exploiting a very large library of physically plausible equations of state (EOSs) containing more than $10^7$ members and yielding more than $10^9$ stellar models, we conduct a survey of the impact that a neutron-star radius measurement via electromagnetic observations can have on the EOS of nuclear matter. Such measurements are soon to be expected from the ongoing NICER mission and will...
The recent GW+EM detection of a neutron star merger has underlined the multitude of physical processes that are needed for a reliable prediction of multi-messenger signals. In the talk I will discuss the various processes that lead from the merger to the electromagnetic emission. Particular attention will be payed to topics where our understanding is incomplete and more progress is needed.
A robust and quantitative understanding of neutron star mergers requires detailed numerical simulations. The latter must include all the relevant physics, resolve the necessary lenght scales, and cover all the important temporal phases. The key role of all fundamental interactions makes this task extremely challenging. In this talk, I will briefly summarize the present status of the field and...
I will present results of general relativistic hydrodynamic (GRHD) simulations of binary neutron star (BNS) mergers with a hybrid leakage-transport scheme for the neutrino treatment. I will discuss the matter dynamics and show the thermodynamic conditions of the fluid in the region where the three evolved neutrino species decouple from matter. Finally, I will give an overview of the...
We present FO-CCZ4, a strongly hyperbolic first-order formulation of the Einstein
equations based on the conformal and covariant Z4 system with constraint-violation damping. This formulation combines the advantages of a conformal and traceless formulation, with the suppression of constraint violations given by the damping terms, but being first order in time and space, it is particularly...
With the detection of GW170817 we have observed the first multi messenger signal from two merging neutron stars.
This signal carried a multitude of information about the underlying equation of state (EOS) of nuclear matter, which so far is not known for densities above nuclear saturation. In particular it is not known if exotic states or even a phase transition to quark matter can occur at...
Neutron star merger is a unique cosmic laboratory to investigate general relativity in a strong field regime and fundamental physics, including dense matter and heavy-elements-nucleosynthesis.
Our work focuses on the electromagnetic counterpart of the gravitational wave source GW170817. We study the merger dynamics and light curves employing the state of the art numerical, general...
Merging neutron stars are both gravitational wave and electromagnetic transient sources, as confirmed by the detection of the GW170817 event. The gravitational wave emission was indeed followed by emission all across the electromagnetic spectrum, including an optical and infrared signal known as macronova. This signal is powered by the radioactive decay of freshly synthesized r-process...
Thirty years after both the light and neutrino emission was observed from SN1987A, the neutron star merger event GW170817 demonstrated the power of new tools in multi-messenger astronomy. Since LIGO/VIRGO gravitational wave detection enables identification and pointed electromagnetic follow-up of merger events, new insights into these rare and interesting systems can be gained. The...
Core-collapse supernovae (CCSNe) are one of the most important sites of element synthesis in the universe and drive the chemical evolution of galaxies. A major goal of CCSN nucleosynthesis studies is to determine how nucleosynthesis outcomes depend on progenitor properties (e.g. mass and metallicity) and the explosion details. Traditional calculations do not account for neutrino-matter...
Neutrino-driven winds emerging after a successful core-collapse
supernovae can produce the lighter heavy elements between Fe and Ag depending on the
properties of the ejecta.
However, despite the fast progress in supernovae simulations in the last
decades, there are still large uncertainties in the astrophysical
conditions.
We rely on a steady-state neutrino-driven wind model to
...
The origin of the heaviest elements is still a matter of debate. For the rapid neutron
capture process (“r-process”), multiple sites have been proposed, e.g., neutron star
mergers and (sub-classes) of supernovae. R-process elements have been measured in
metal-poor halo stars. Galactic archaeology studies show that the r-process abundances
among these stars vary by over two orders of magnitude....
The astrophysical production site of the heaviest elements in the universe remains a mystery. Incorporating heavy element signatures of metal-poor, r-process enhanced stars into theoretical studies of r-process-process production can offer crucial constraints on the origin of heavy elements. In this study, we apply the "Actinide-Dilution with Matching" model to a variety of...
