Methods in Time Domain Analysis of Gravitational Wave Data

Definitive confirmation of the detection of gravitational waves will require strong independent detections from at least two sources which may include the opportunity for astronomical observation of associated electromagnetic and/or neutrino bursts. For these events, the most energetic of which may be of short duration, to be confirmed astronomically it is necessary to pass source location information to astronomical instruments with sufficient low latency to supply steering information to the instruments
before fading of any counterpart. Furthermore, the limitations on computing resources for searches, and the likelihood that at least some sources are likely to have waveforms poorly localised in a time-frequency basis, leads us to seek a search method that operates primarily in the time domain.
We present a rapid time domain exponential cross-correlation indicator which is capable of generating event triggers with a latency on the order of signal duration whilst providing
source resolution. A complete analysis pipeline was developed and trigger method tested using archived data from the LIGO H1 (Hanford, WA) and L1 (Livingston, LA) detectors.
Standard data preprocessing techniques such as linear predictive filtering were combined with novel line removal methods. The events selected by this algorithm were further processed by novel level 2 signal enhancement and parameterisation algorithms. Detection efficiency and false alarm rate results were generated from mock data challenge
injection signals added to data from the S6/VSR3 science run of initial LIGO. Our results indicate that this search algorithm is a good candidate for an unmodelled burst pipeline complementary to the existing codes, and having certain advantages over these codes in terms of latency, computational burden and robustness.