Neutrino Trapping and Out-of-Equilibrium Effects in Binary Neutron-Star Merger Remnants.

We study out-of-thermodynamic-equilibrium effects in neutron-star mergers with 3D general-relativistic neutrino-radiation large-eddy simulations. During mergers, the cores of the neutron stars remain cold (T∼ a few MeV) and out of thermodynamic equilibrium with trapped neutrinos originating from the hot collisional interface between the stars. However, within ∼2 to 3 ms matter and neutrinos reach equilibrium everywhere in the remnant massive neutron star.

Probing the Incompressibility of Nuclear Matter at Ultrahigh Density through the Prompt Collapse of Asymmetric Neutron Star Binaries.

Using 250 neutron star merger simulations with microphysics, we explore for the first time the role of nuclear incompressibility in the prompt collapse threshold for binaries with different mass ratios. We demonstrate that observations of prompt collapse thresholds, either from binaries with two different mass ratios or with one mass ratio but combined with the knowledge of the maximum neutron star mass or compactness, will constrain the incompressibility at the maximum neutron star density K_{max} to within tens of percent. This otherwise inaccessible measure of K_{max} can potentially reveal the presence of hyperons or quarks inside neutron stars.

Constraints on the Maximum Densities of Neutron Stars from Postmerger Gravitational Waves with Third-Generation Observations.

Using data from 289 numerical relativity simulations of binary neutron star mergers, we identify, for the first time, a robust quasiuniversal relation connecting the postmerger peak gravitational-wave frequency and the value of the density at the center of the maximum mass nonrotating neutron star. This relation offers a new possibility for precision equation-of-state constraints with next-generation ground-based gravitational-wave interferometers. Mock Einstein Telescope observations of fiducial events indicate that Bayesian inferences can constrain the maximum density to ∼15% (90% credibility level) for a single signal at the minimum sensitivity threshold for a detection.

Positrons and 511 keV Radiation as Tracers of Recent Binary Neutron Star Mergers.

Neutron-rich material ejected from neutron star-neutron star (NS-NS) and neutron star-black-hole (NS-BH) binary mergers is heated by nuclear processes to temperatures of a few hundred keV, resulting in a population of electron-positron pairs. Some of the positrons escape from the outer layers of the ejecta. We show that the population of low-energy positrons produced by NS-NS and NS-BH mergers in the Milky Way can account for the observed 511-keV line from the Galactic center (GC).

Gravitational-Wave Luminosity of Binary Neutron Stars Mergers.

We study the gravitational-wave peak luminosity and radiated energy of quasicircular neutron star mergers using a large sample of numerical relativity simulations with different binary parameters and input physics. The peak luminosity for all the binaries can be described in terms of the mass ratio and of the leading-order post-Newtonian tidal parameter solely. The mergers resulting in a prompt collapse to black hole have the largest peak luminosities.

A large-scale dynamo and magnetoturbulence in rapidly rotating core-collapse supernovae.

Magnetohydrodynamic turbulence is important in many high-energy astrophysical systems, where instabilities can amplify the local magnetic field over very short timescales. Specifically, the magnetorotational instability and dynamo action have been suggested as a mechanism for the growth of magnetar-strength magnetic fields (of 10(15) gauss and above) and for powering the explosion of a rotating massive star. Such stars are candidate progenitors of type Ic-bl hypernovae, which make up all supernovae that are connected to long γ-ray bursts.

Cost-effectiveness of hypothetical new cancer drugs in patients with advanced small-cell lung cancer: results of a markov chain model.

Background: In the last decade, a number of new treatment modalities have been developed for patients with small cell lung cancer (SCLC). The clinical effects are encouraging, but little is known about the costs and cost-effectiveness of new drugs.

Methods: A Markov chain model has been developed to project patient outcomes and costs for patients with advanced SCLC.