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Full White Paper LIGO SCIENTIFIC COLLABORATION VIRGO COLLABORATION Document Type LIGO–T1400054 VIR-0176A-14 The LSC-Virgo White Paper on Gravitational Wave Searches and Astrophysics (2014-2015 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 2014/11/21 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 Signals from Compact Binary Coalescences . .5 1.2 Searches for Generic Transients, or Bursts . .7 1.3 Searches for Continuous Wave Signals . .9 1.4 Searches for Stochastic Gravitational Wave Backgrounds . 11 1.5 Characterization of the Detectors and their Data . 13 1.6 Data Calibration . 15 1.7 Hardware Injections . 16 1.8 Computing and Software . 17 2 Previous Accomplishments (2013-2014) 19 2.1 Burst Working Group . 19 2.2 Compact Binary Coalescences Working Group . 19 2.3 Continuous Waves Group . 20 2.4 Stochastic Group . 21 2.5 Detector Characterization . 21 3 Search Plans for the Advanced Detector Era 23 3.1 All-Sky Burst Search . 24 3.2 Search For Binary Neutron Star Coalescences . 29 3.3 Search for Stellar-Mass Binary Black Hole Coalescences . 37 3.4 Search For Neutron Star – Black Hole Coalescences . 45 3.5 Search for GRB Sources of Transient Gravitational Waves . 57 3.6 Search for Intermediate Mass Black Hole Binary Coalescences . 64 3.7 All-sky Searches for Isolated Spinning Neutron Stars . 69 3.8 Targeted Searches for Gravitational Waves from Known Pulsars . 77 3.9 Search for an Isotropic Stochastic Gravitational Wave Background . 82 3.10 Directional Search for Persistent Gravitational Waves . 88 3.11 Directed Searches for Gravitational Waves from Isolated Neutron Stars . 94 3.12 Directed Searches for Scorpius X-1 and Other Known Binary Stars . 100 3.13 Search for transients from Cosmic Strings . 110 3.14 All-sky Searches for Spinning Neutron Stars in Binary Systems . 114 3.15 Search for Eccentric Binary Black Holes . 120 3.16 Search for Intermediate-mass-ratio Coalescences . 125 3.17 High-energy Neutrino Multimessenger Analysis . 131 3.18 Searches For Transient Gravitational Waves From Isolated Neutron Stars . 136 3.19 Gravitational-Waves from Galactic and Near-Extragalactic Core-Collapse Supernovae . 143 3.20 Search for transients in coincidence with Fast Radio Bursts . 149 3.21 Contributions of long transient gravitational waves to the stochastic background search . 152 4 Ongoing searches on Initial Detector Data and activities not ready for a Search Plan 156 4.1 Burst Working Group . 156 4.2 Compact Binary Coalescences Working Group . 166 4.3 Continuous Waves Group . 168 4.4 Stochastic Group . 194 2 The LSC-Virgo White Paper on Gravitational Wave Searches and Astrophysics 5 Characterization of the Detectors and Their Data 200 5.1 LSC Detector Characterization . 200 References 214 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 into four LSC-Virgo working groups: compact binary coalescences (CBC), generic transients (Burst), continuous waves (CW) and stochastic gravitational-wave background (SGWB). Each of these groups pursues distinct astrophysical sources of gravitational waves with different methods. Joint teams formed from the members of two or more working groups exist, where the science suggests over- lap between sources or methods. In addition to these astrophysics groups, the Detector Characterization group, which also collaborates with the detector commissioning teams, works to improve search sensitivity by identifying and mitigating instrumental noise sources that limit the sensitivity to astrophysical signals. The LSC-Virgo White Paper on Gravitational Wave Searches and Astrophysics describes the goals, status, and plans of the data analysis teams in the LSC and Virgo, as well as plans and status of Detector Characteri- zation, calibration and development and maintenance of software tools and the management of software and computing resources. This document, which is revised and updated every year, is intended to facilitate the understanding of the science that we are pursuing, the prioritization of our objectives, the development plan and resource needs. The 2014-2015 version offers a significant re-structure from previous year, resulting from discussions in the LSC-Virgo Data Analysis Council, with four components: 1. Chapter 1 is the executive summary for this white paper, outlining for each search group a mission statement and a ranked list of priorities both in terms of scientific targets and tasks in preparation for Advanced LIGO and Advanced Virgo. 2. Chapter 2 lists papers and milestones from the period May 2013-May 2014. 3. Chapter 3 is a collection of search plans for Advanced LIGO and Advanced Virgo, with details on developments and resources. The plans can also be read as standalone documents and will be updated on a 6-month timescale. 4. Chapter 4 includes ongoing analysis on initial detector data or exploratory work that do not yet fit the search plan template. We refer to the Advanced Detector Era (ADE) as the epoch of Advanced LIGO and Advanced Virgo science data acquisition, currently scheduled to start in the second half of 2015. The schedule of science run is formulated by the LSC-Virgo Joint Running Plan Committee, which includes representatives from the laboratories, the commissioning teams and search groups, and the plans are formulated according to the schedule outlined in the document "Prospects for Localization of Gravitational Wave Transients by the Advanced LIGO and Advanced Virgo Observatories" (arXiv:1304.0670). −2 2 Estimated EGW = 10 M c Number % BNS Localized Run Burst Range (Mpc) BNS Range (Mpc) of BNS within Epoch Duration LIGO Virgo LIGO Virgo Detections 5 deg2 20 deg2 2015 3 months 40 – 60 – 40 – 80 – 0.0004 – 3 – – 2016–17 6 months 60 – 75 20 – 40 80 – 120 20 – 60 0.006 – 20 2 5 – 12 2017–18 9 months 75 – 90 40 – 50 120 – 170 60 – 85 0.04 – 100 1 – 2 10 – 12 2019+ (per year) 105 40 – 80 200 65 – 130 0.2 – 200 3 – 8 8 – 28 2022+ (India) (per year) 105 80 200 130 0.4 – 400 17 48 Table 1: Summary of a plausible observing schedule, expected sensitivities, and source localization with the advanced LIGO and Virgo detectors, which will be strongly dependent on the detectors’ commissioning progress. Extracted from arXiv:1304.0670 4 The LSC-Virgo White Paper on Gravitational Wave Searches and Astrophysics 1.1 Searches for Signals from Compact Binary Coalescences The inspiral and merger of a binary containing stellar-mass compact objects (i.e., neutron stars and black holes) generates gravitational waves which sweep upward in frequency and amplitude through the sensitive band of ground-based gravitational-wave detectors. The highly relativistic speeds and strongly- curved spacetimes of compact object mergers generate gravitational waves that will reveal the physics of strong-field gravity. The gravitational waves from mergers involving black holes will allow us to explore General Relativity and the nature of gravity. With densities of matter inaccessible to terrestrial experiments, mergers involving neutron stars hold the key to understanding the equation of state of nuclear matter. This is a crucial piece of fundamental physics missing from our understanding of the universe. Compact object mergers may also explain the origin and distribution of rare heavy elements and reveal the engine powering gamma-ray bursts. Measuring the masses and spins of a population of compact objects in the universe can help explain how stellar collapse forms neutron stars and black holes. At design sensitivity, Advanced LIGO will be able to detect binary neutron star (BNS) mergers to a maximum distance of 400 Mpc, neutron star–black hole (NSBH) binaries to 1 Gpc, and stellar-mass binary black holes (BBHs)∼ at distances over 2 Gpc. LIGO and Virgo conduct their∼ searches jointly giving us a three-detector network that can be used to localize sources on the sky. A wide variety of electromagnetic counterparts are expected to accompany the gravitational waves from compact object mergers, ranging from radio, through optical to x-rays and gamma-rays. The joint observation of a source by LIGO, Virgo, high- energy satellites, optical, and radio observatories will be a watershed event in astrophysics. The scientific program of the LSC/Virgo Compact Binary Coalescence (CBC) Group is designed to identify gravitational wave signals from compact binary sources in the detector data, measure the waveform parameters, and use detected signals study the nature of gravity and the astrophysics of nature’s most com- pact objects. Detection and parameter measurement of CBC signals is carried out by the joint LSC-Virgo CBC working group. The CBC group’s science program requires accurate modeling of gravitational wave sources to maximize detection rates, and to accurately measure parameters. The CBC group has an active collaboration with the theoretical astrophysics, source modeling and numerical relativity communities to address these challenges. The LSC charter states that the mission of the LSC is to detect gravitational waves, use them to explore the fundamental physics of gravity, and develop gravitational wave observations as a tool of astronomical discovery. We prioritize CBC tasks both in view of this mission statement and in terms of their chronological importance in the advanced detector era. Accordingly, highest priority is given to the ability to detect the most probable CBC sources with the LIGO and Virgo detectors, followed by science with the first detections (high priority), and finally the detection of sources which in the current astrophysical paradigm may have a low rate within the detectors’ volume reach, but whose discovery would nevertheless be of great astrophysical importance (priority).
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