Retrieving "Gravitational Waveform" from the archives

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1. Binary Neutron Star System

   Linked via "gravitational waveform"

   Gravitational Wave Detections
   The direct observation of gravitational waves from inspiraling BNSs, beginning with GW170817, confirmed decades of theoretical predictions. Analysis of the gravitational waveform allows for precise determination of system parameters, including the chirp mass ($\mathcal{M}$):
   $$\mathcal{M} = \frac{(m1 m2)^{3/5}}{(m1 + m2)^{1/5}}$$

2. Numerical Relativity

   Linked via "waveform"

   Boundary Conditions and Outer Boundaries
   Simulations are performed on a finite computational domain. Since gravitational waves carry physical information outward, the outer boundary must allow these waves to exit the domain without reflection. This is achieved using Absorbing Boundary Conditions (ABCs), such as Neumann or Sommerfeld conditions, carefully tuned to the local wave speed dictated by the local lapse and shift. Improper ABC tuning often causes spurious reflections, contaminating the computed [wavefor…

3. Numerical Relativity

   Linked via "gravitational waveform"

   Waveform Extraction and Analysis
   The output of a successful NR simulation is a time evolution of the $3+1$ variables across the spatial domain, from which the physical observable—the gravitational waveform—must be extracted. This is typically done by analytically continuing the solution into the radiative zone (asymptotically far from the source) and projecting the metric perturbations onto spherical harmonics at fixed coordinate radii, yielding the strain $h_{+,\times}(t, r)$.
   The characteristic signal from a [binary sy…