## Physics & Astronomy

#### Event Title

Dynamical Ejecta Mass and Gravitational Wave Emission from High Mass-Ratio Binary Neutron Star Mergers

#### Document Type

Poster Presentation

#### Location

Indianapolis, IN

#### Start Date

13-4-2018 2:30 AM

#### End Date

13-4-2018 4:00 PM

#### Sponsor

Aaron Warren (Purdue University Northwest)

#### Description

The current generation of gravitational wave detectors, including Advanced LIGO, is opening a new field of observational astronomy. With the direct detection of a binary neutron star merger, GW170817, a wealth of information about neutron stars, gamma-ray bursts, and kilonovae has been obtained. One major source of uncertainty in the analysis of GW170817 is the relationship between the dynamical ejecta mass and the mass-ratio of binary neutron star systems. In particular, observations of kilonova emission may be used to estimate the dynamical ejecta mass, which may then be used to estimate the mass-ratio. The uncertainty of the relation between ejecta mass and mass-ratio is rather large (~72%) and numerical relativity simulations are needed to reduce this uncertainty. We are currently conducting a series of simulations studying the ejecta mass amounts for high mass-ratio systems (q > 1.5) that are consistent with estimates from GW170817. In particular, results for a 1.9-1.1Msol binary (q = 1.73), at a range of resolutions, will be shared. These simulations employ a 7-component piecewise-polytrope approximation to a realistic equation-of-state (Sly4) that is consistent with GW170817. The system is evolved with both unmagnetized and magnetized initial conditions, and we discuss preliminary differences in ejecta mass and gravitational wave signatures between these two situations.

Dynamical Ejecta Mass and Gravitational Wave Emission from High Mass-Ratio Binary Neutron Star Mergers

Indianapolis, IN

The current generation of gravitational wave detectors, including Advanced LIGO, is opening a new field of observational astronomy. With the direct detection of a binary neutron star merger, GW170817, a wealth of information about neutron stars, gamma-ray bursts, and kilonovae has been obtained. One major source of uncertainty in the analysis of GW170817 is the relationship between the dynamical ejecta mass and the mass-ratio of binary neutron star systems. In particular, observations of kilonova emission may be used to estimate the dynamical ejecta mass, which may then be used to estimate the mass-ratio. The uncertainty of the relation between ejecta mass and mass-ratio is rather large (~72%) and numerical relativity simulations are needed to reduce this uncertainty. We are currently conducting a series of simulations studying the ejecta mass amounts for high mass-ratio systems (q > 1.5) that are consistent with estimates from GW170817. In particular, results for a 1.9-1.1Msol binary (q = 1.73), at a range of resolutions, will be shared. These simulations employ a 7-component piecewise-polytrope approximation to a realistic equation-of-state (Sly4) that is consistent with GW170817. The system is evolved with both unmagnetized and magnetized initial conditions, and we discuss preliminary differences in ejecta mass and gravitational wave signatures between these two situations.