LIGO SCIENTIFIC COLLABORATION VIRGO COLLABORATION Document Type LIGO–T1600115 VIR-0347A-16 The LSC-Virgo White Paper on Gravitational Wave Searches and Astrophysics (2016-2017 edition) The LSC-Virgo Search Groups, the Data Analysis Software Working Group, the Detector Characterization Working Group and the Computing Committee WWW: http://www.ligo.org/ and http://www.virgo.infn.it Processed with LATEX on 2016/11/10 The LSC-Virgo White Paper on Gravitational Wave Searches and Astrophysics Contents 1 The LSC-Virgo White Paper on Data Analysis 4 1.1 Searches for Generic Transients, or Bursts . .6 1.2 Searches for Signals from Compact Binary Coalescences . .8 1.3 Searches for Continuous-wave Signals . 10 1.4 Searches for Stochastic Backgrounds . 12 1.5 Characterization of the Detectors and their Data . 14 1.6 Data Calibration . 16 2 Previous Accomplishments 18 3 Search Plans for the Advanced Detector Era 18 3.1 All-Sky Short-Duration Burst Search . 19 3.2 Catalogue of Compact Binaries . 25 3.3 Astrophysical Distributions of Compact Binaries . 27 3.4 Multimessenger Astronomy and Astrophysics with Compact Binaries: GW alerts . 27 3.5 Searching for Gamma Ray Burst Counterparts to Compact Binaries . 28 3.6 Testing General Relativity with Compact Binaries . 29 3.7 Characterizing Exceptional Compact Binary Coalescence Events . 30 3.9 Search for GRB Sources of Transient Gravitational Waves . 31 3.10 Search for Intermediate Mass Black Hole Binary Coalescences . 39 3.11 Search for Eccentric Binary Black Holes . 44 3.12 Search for Intermediate-mass-ratio Coalescences . 49 3.13 High-energy Neutrino Multimessenger Analysis . 55 3.14 Search for transients from Cosmic Strings . 60 3.15 Search plan for long-lived gravitational-wave transients . 64 3.16 Searches For Transient Gravitational Waves From Isolated Neutron Stars . 69 3.17 Gravitational-Waves from Galactic and Near-Extragalactic Core-Collapse Supernovae . 77 3.18 Search for transients in coincidence with Fast Radio Bursts . 84 3.19 All-sky Searches for Isolated Spinning Neutron Stars . 88 3.20 Targeted Searches for Gravitational Waves from Known Pulsars . 97 3.21 Directed Searches for Gravitational Waves from Isolated Neutron Stars . 102 3.22 Directed Searches for Scorpius X-1 and Other Known Binary Stars . 108 3.23 All-sky Searches for Spinning Neutron Stars in Binary Systems . 118 3.24 Search for an Isotropic Stochastic Gravitational Wave Background . 124 3.25 Directional Search for Persistent Gravitational Waves . 130 3.26 Contributions of long transient gravitational waves to the stochastic background search . 136 4 Characterization of the Detectors and Their Data 140 4.1 LSC Detector Characterization . 140 4.2 Detailed LIGO Detector Characterization priorities . 141 4.3 Overarching goals . 141 4.4 Characterizing Instrumental Artifacts . 141 4.5 Improving search data quality . 142 4.6 Essential Software and Automation . 143 4.7 Development of New Methods . 144 4.8 Ongoing Tasks . 145 2 The LSC-Virgo White Paper on Gravitational Wave Searches and Astrophysics 4.9 Roles . 146 5 Calibration 147 5.1 LIGO calibration . 147 5.2 LIGO timing diagnostics . 148 References 150 3 The LSC-Virgo White Paper on Gravitational Wave Searches and Astrophysics 1 The LSC-Virgo White Paper on Data Analysis Gravitational wave searches and astrophysics in the LIGO Scientific Collaboration (LSC) and Virgo collab- oration are organized by astrophysical source classification into four working groups. The Compact Binary Coalescence (CBC) group searches for signals for merging neutron stars or black holes by filtering the data with waveform templates. The Burst (Burst) group searches for generic gravitational wave transients with minimal assumption on the source or signal morphology. The Continuous Waves (CW) group targets pe- riodic signatures from rotating neutron stars. The Stochastic (SGWB) group looks for a gravitational wave background of cosmological or astrophysical origin. Joint teams across two or more working groups exist where the science suggests overlap between sources or methods. In addition, the Detector Characteriza- tion (Detchar) group collaborates with the detector commissioning teams and works to improve searches by identifying and mitigating noise sources that limit sensitivity to astrophysical signals. The LSC-Virgo White Paper on Gravitational Wave Searches and Astrophysics, which is updated yearly, describes the astrophysical search plans of the LSC-Virgo working groups. This document is its executive summary. For each group, it provides a mission statement and scientific priorities in the Advanced Detector Era, as well as statements from Detector Characterization, Calibration and Hardware Injection teams. We refer to the Advanced Detector Era (ADE) as the epoch of Advanced LIGO and Advanced Virgo sci- ence data acquisition, which began in September 2015 and has already yielded the first direct observation of gravitational waves by the Advanced LIGO detectors [PRL 116, 131103 (2016), PRL 116, 241103 (2016)]. Table 1 shows the planned schedule of science runs, as provided by the LSC-Virgo Joint Running Plan Com- mittee, which includes representatives from the laboratories, the commissioning teams and search groups. −2 2 Estimated EGW = 10 M c Binary Neutron Star Number of Run Run Burst Range (Mpc) Range (Mpc) Binary Neutron Star Epoch Duration Name LIGO Virgo LIGO Virgo Detections 2015–16 4 months O1 20 – 30 – 68 – 78 – – actual [1,2] 2016–17 6 months O2 60 – 75 20 – 40 80 – 120 20 – 60 0.006 – 20 projected [3] 2017–18 9 months O3 75 – 90 40 – 50 120 – 170 60 – 85 0.04 – 100 projected [3] Table 1: Plausible observing schedule and expected sensitivities for the Advanced LIGO and Virgo detectors. The O1 Burst range is for ∼ 150 Hz signals, from [1 – arXiv:1611.02972] . The O1 BNS range is from [2 – arXiv:1607.07456]. Projected sensitivity for O2 and O3 will be strongly dependent on commissioning progress [3 – Living Rev. Relativity 19 (2016), 1]. The LSC-Virgo scientific priorities for ADE observations are summarized in Table 2, by search group, in three categories: • Highest priority: searches most likely to make detections or yield significant astrophysical results. • High priority: promising extensions of the highest priority goals that explore larger regions of pa- rameter space or can further the science potential of LIGO and Virgo. • Additional priority: sources with low detection probability but high scientific payoff. Computing needs and resource allocations are derived from the science priorities presented in this table. Scientific motivations, details on methods and the strategy for result validation are provided in the search plans that constitute the white paper. We note that the LSC-Virgo Collaboration has adopted a Multiple Pipeline Policy [LIGO-M1500027], which calls for all astrophysical results to be validated with a different analysis, using independent methods and tools when possible. In some cases this may require the same data to be analyzed by more than one pipeline for the same science target. 4 The LSC-Virgo White Paper on Gravitational Wave Searches and Astrophysics Burst CBC CW SGWB All-sky search for generic Detecting the coalescence of All-sky search for isolated Directional search for GW transients, in low latency neutron star and black hole neutron stars, both as a quick- stochastic GW background for EM followup and deep, binaries and measuring their look on owned resources and offline for 4σ detection con- parameters as a deep/broad search on fidence Einstein@Home Parameter estimation for the Characterizing the astrophys- Targeted search for high Isotropic search for stochas- astrophysical interpretation ical distribution of compact value, known pulsars tic GW background of detected burst events binaries Search for GW bursts trig- Responding to exceptional Directed searches for most Constraints of a detected gered by outstanding GRB CBC detections promising isolated stars (Cas background of astrophysical alerts A, Vela Jr etc.) origin with long transients Searches triggered by out- Multi-messenger astronomy Directed searches for X-ray Highest priority standing astrophysical events with compact binaries binaries SCO-X1 and J1751- (a galactic supernova, neu- 305 tron star transients, an excep- tional high energy neutrino alert) Search for cosmic string Searching for CBC-GRB co- kinks and cusps incidences Testing General Relativity with Compact Binaries Searches triggered by high All sky search for spinning Targeted search for other Long transient follow up of energy neutrinos, extra- binary neutron star systems known pulsars CBC and burst candidates galactic supernovae, and (deep and low latency) GRB observations Burst search for intermedi- Matched filtered search for Directed searches for other ate mass ratio and eccentric intermediate mass black hole isolated stars and X-ray bina- High priority black hole binary systems binary systems ries All-sky search for long bursts of > 10 s duration GRB-triggered search for Exploring effects of detector All sky search for isolated long-duration bursts and noise on parameter estima- stars (alternative approaches) plateaus tion Hypermassive neutron star Searching for sub-solar mass All-sky search for binaries followup CBC signals Burst searches triggered Developing searches for Spotlight deep sky-patch by radio transients and by CBC signals with generic search ∗∗ SGR/SGR-QPO spins Additional priority Burst tests of alternative Search for Supernova post gravity theories ∗∗ birth signals ∗∗ Search for continuous wave transients