Compact binary coalescence searches with low latency: why and how

Low-latency gravitational-wave (GW) detection of a compact binary coalescence (CBC) will allow electromagnetic (EM) followups to observe earlier parts of the corresponding lightcurves, which are brighter, convey more information about the progenitor system, and allow a more confident association of GW and EM transients. Conventional matched filter banks, common in CBC searches, are computationally efficient, but incur a latency of many minutes. Searches with latencies of seconds and significantly increased throughput are achievable with techniques such as principal component analysis, to reduce the number of filtered templates, hierarchical detection with singular value decomposition by-products, and exploitation of the quasi-monochromatic structure of chirps to filter time-slices at different sample rates. We present an implementation of these ideas called LLOID, based on the LSC Algorithm Library and the GStreamer multimedia framework.