题目: Localization accuracy of compact binary coalescences detected by the third-generation gravitational-wave detectors and implication for cosmology

时间地点：12月14号 下午2：00—3：00 理学楼二楼教师活动中心

Abstract: We use the Fisher information matrix to investigate the angular resolution and luminosity distance uncertainty for coalescing binary neutron stars (BNSs) and neutron star-black hole binaries (NSBHs) detected by the third-generation (3G) gravitational-wave (GW) detectors. Our study focuses on an individual 3G detector and a network of up to four 3G detectors at different locations including the US, Europe, China and Australia for the proposed Einstein Telescope (ET) and Cosmic Explorer (CE) detectors and an ideal detector with a flat low-frequency sensitivity. We find that, due to the effect of the Earth's rotation, a time-dependent antenna beam-pattern function can help better localize BNS and NSBH sources, especially those edge-on ones. We use numerical simulations to study the localization for a random sample of (1.4+1.4) ${rm M}_odot$ BNSs and low-mass NSBHs of (1.4+10) ${rm M}_odot$ at various redshifts. The medium angular resolution for a network of two CE detectors in the US and Europe respectively is around 20 deg$^2$ at $z=0.2$ for our BNS and NSBH samples. A 20 deg$^2$ medium angular resolution can be achieved for a network of two ET-D detectors at a much higher redshift of $z=0.5$ than for two CEs. We discuss the implications of our results to multi-messenger astronomy and in particular to using GW sources as independent tools to constrain the cosmological parameters. We find that in general, if 10 BNSs or NSBHs at $z=0.1$ with known redshifts are detected with $le 50%$ distance uncertainty by 3G networks consisting of two ET-like detectors, the Hubble constant $H_0$ can be measured with an accuracy of $0.9%$. If 1000 face-on BNSs at $z<2$ are detected with known redshifts, we are able to constrain the equation-of-state parameters of dark energy $w_0$ and $w_a$ with accuracies $Delta w_0=0.03$ and $Delta w_a=0.2$, respectively.