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Multi ifo coherent followup

Thomas Dent edited this page Aug 29, 2018 · 5 revisions

PyCBC Offline multi-ifo search with coherent followup

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Context

O3+ searches will involve 3+ advanced detectors taking data simultaneously (as did last ~month of O2). Dal Canton thesis (2015) indicates that for 3 or more ifos, an all-sky coherent search is more sensitive at given false alarm rate if sufficient computing power is available to search a dense sky grid. (See also Macleod et al. arXiv:1509.03426 for a coherent H1H2L1 search.)

Practically, this can be efficiently implemented by a hierarchical (followup) search where a coherent stage is run for all times indicated by a 2-ifo coincidence search with low thresholds.

Development

Development will involve extending the 2-ifo H-L coincidence stage to all 3-ifo combinations (H-L, H-V, L-V) and supplementing the coincidence finding with a coherent followup module.

First steps towards this have been taken on Marton's development branch - see LVC-only wiki [https://www.lsc-group.phys.uwm.edu/ligovirgo/cbcnote/PyCBC/O3/O3-multi-detector-development] for more details. (Progress documentation will be transferred here.)

Future code development will proceed on the master branch of PyCBC.

Background estimation

1d time slides

Prototyping & testing

Synthetic / open 3-ifo data will be used for testing and comparison of sensitivity, methods paper etc. For instance some chunks of O1 H1-L1 data with time-shifted O1 data relabelled (and relocated) to serve as V1.

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