Find in Library

Using a data set of approximately 2 million phenomenological equations of state consistent with observational constraints, we construct new equation-of-state-insensitive universal relations that exist between the multipolar tidal deformability parameters of neutron stars, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi mathvariant="sans-serif">Λ</mi><mi>l</mi></msub></semantics></math></inline-formula>, for several high-order multipoles (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>l</mi><mo>=</mo><mn>5</mn><mo>,</mo><mn>6</mn><mo>,</mo><mn>7</mn><mo>,</mo><mn>8</mn></mrow></semantics></math></inline-formula>), and we consider finite-size effects of these high-order multipoles in waveform modeling. We also confirm the existence of a universal relation between the radius of the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.4</mn><msub><mi>M</mi><mo>⊙</mo></msub></mrow></semantics></math></inline-formula> NS, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>R</mi><mrow><mn>1.4</mn></mrow></msub></semantics></math></inline-formula> and the reduced tidal parameter of the binary, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mover accent="true"><mi mathvariant="sans-serif">Λ</mi><mo>˜</mo></mover></semantics></math></inline-formula>, and the chirp mass. We extend this relation to a large number of chirp masses and to the radii of isolated NSs of different mass <i>M</i>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>R</mi><mi>M</mi></msub></semantics></math></inline-formula>. We find that there is an optimal value of <i>M</i> for every <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">M</mi></semantics></math></inline-formula> such that the uncertainty in the estimate of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>R</mi><mi>M</mi></msub></semantics></math></inline-formula> is minimized when using the relation. We discuss the utility and implications of these relations for the upcoming LIGO O4 run and third-generation detectors.