Fast localization of coalescing binaries with a heterogeneous network of advanced gravitational wave detectors

Abstract

We present the expected performance regarding fast sky localization of coalescing binaries with a network of three gravitational wave detectors having heterogeneous sensitivities, such as the LIGO-Virgo network. A hierarchical approach can be used in order to make an effective use of information from the least sensitive detector. In this approach, the presence of an event seen in coincidence in the two more sensitive detectors triggers a focused search in the data of the third, less sensitive, detector with a lower signal-to-noise ratio (SNR) threshold. We investigate the benefit for sky localization that can be expected in such an approach, using simulated data and signals. We find that as the sensitivity of Virgo approaches one third of the LIGO sensitivity, the accuracy and precision of the localization can be improved by about a factor 3 when Virgo data are searched with an SNR threshold around 3.5.

Optimal sensor fusion method for active vibration isolation systems in ground-based gravitational-wave detectors

“…In this section, the proposed method will be demonstrated by synthesizing complementary filters for blending an LVDT and a geophone, referred to as sensor 1 and sensor 2, respectively. The sensor noises are taken from figure 5.8 in reference [23], and can be well described by equation (26).…”

“…There are multiple ways to achieve sensor fusion, such as the use of Kalman filters [17,18] and complementary filters [19]. In particular, complementary filters have been widely used in active isolation platforms in gravitational wave detectors [10,13,[20][21][22][23][24][25][26]. Complementary filters are a set of digital filters that can take almost any arbitrary shape so long as their transfer functions are summed to unity.…”

Vibration isolation systems for the beam splitter and signal recycling mirrors of the KAGRA gravitational wave detector

“…Figure 1(a) shows their layout and figure 1(b) shows a 3D CAD rendering of each type. Type-A suspensions [8,9] are used for the most critical optics, namely the input and end test masses, which define the arms of the Fabry-Perot-Michelson interferometer and react to the GW. Each type-A system has an inverted pendulum (IP) stage for horizontal isolation, five stages of geometric anti-spring (GAS) filters for vertical isolation and from it hangs the cryogenic payload.…”

Accuracy of estimation of parameters with space-borne gravitational wave observatory

“…For more discussion on the accuracy of sky localizations, please see Refs. [36][37][38][39][40][41][42][43][44][45][46].…”