Accuracy in measuring the neutron star mass in the gravitational wave parameter estimation for black hole-neutron star binaries

Abstract

Recently, two gravitational wave (GW) signals, named as GW150914 and GW151226, have been detected by the two LIGO detectors. Although both signals were identified as originating from merging black hole (BH) binaries, GWs from systems containing neutron stars (NSs) are also expected to be detected in the near future by the Advanced detector network. In this work, we assess the accuracy in measuring the NS mass (MNS) for the GWs from BH-NS binaries adopting the Advanced LIGO sensitivity with a signal-to-noise ratio of 10. By using the Fisher matrix method, we calculate the measurement errors (σ) in MNS assuming the NS mass of 1 ≤ MNS/M⊙ ≤ 2 and low mass BHs with the range of 4 ≤ MBH/M⊙ ≤ 10. We used the TaylorF2 waveform model where the spins are aligned with the orbital angular momentum, but here we only consider the BH spins. We find that the fractional errors (σ/MNS × 100) are in the range of 10% − 50% in our mass region for a given dimensionless BH spin as χBH = 0. The errors tend to increase as the BH spin increases, and this tendency is stronger for higher NS masses (or higher total masses). In particular, for the highest mass NSs (MNS = 2 M⊙), the errors σ can be larger than the true value of MNS if the dimensionless BH spin exceeds ∼ 0.6.

Gravitational Waves and Tidal Deformability of Neutron Stars

“…라이고 (Laser interferometer gravitational-wave observatory, LIGO) 는 중력파 GW150914 검출을 시작으로 두 블랙홀의 병합 과정에서 발생한 중력파를 다수 검출함으로 써 중력파천문학 분야의 개척을 주도하였다 [1][2][3][4][5][6][7][8][9][10][11][12]. 중력파 검출을 통하여, 기존의 전자기파로는 관측이 되지 않은, 새로운 질량 영역의 블랙홀의 존재가 확인됨으로써 중력파 천문학은 은하 및 별의 진화 연구에 새로운 활력소가 되고 있다.…”

Systematic bias due to nonspinning template waveforms in the gravitational wave parameter estimation for aligned-spin binary black holes

“…(7) [30][31][32]. However, the functional form of the phenomenological waveform model is much more complicated compared to the post-Newtonian models, so we adopt the effective Fisher matrix method in this work.…”