Eccentricity of Merging Neutron Star Binaries: Searches, Parameter Estimation, and Future Prospects

Since the start of the first observing run the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Advanced Virgo observatory have detected 48 binary black hole mergers and two binary neutron star mergers. Knowledge about the properties of the binary can be gained from the gravitational-wave observations. Binary neutron star systems can form with significant orbital eccentricity. Gravitational radiation efficiently removes this eccentricity from the binary\u27s orbit as the star\u27s inspiral together. This thesis describes a search for neutron star binaries that have an eccentric orbits when their gravitational waves enter the sensitive band of Advanced LIGO and Virgo. For the detected binary neutron star mergers GW170817 and GW190425, Bayesian parameters estomation is used to constrain the binary\u27s orbital eccentricity. Finally, we consider the prospects of Cosmic Explorer, a planned third-generation gravitational-wave observatory, to detected eccentric binary neutron stars and measure their eccentricity. This analysis has important implications for the computational cost of the search for binaries in quasi-circular orbits with Cosmic Explorer

The PyCBC search for gravitational waves from compact binary coalescence

We describe the PyCBC search for gravitational waves from compact-object binary coalescences in advanced gravitational-wave detector data. The search was used in the first Advanced LIGO observing run and unambiguously identified two black hole binary mergers, GW150914 and GW151226. At its core, the PyCBC search performs a matched-filter search for binary merger signals using a bank of gravitational-wave template waveforms. We provide a complete description of the search pipeline including the steps used to mitigate the effects of noise transients in the data, identify candidate events and measure their statistical significance. The analysis is able to measure false-alarm rates as low as one per million years, required for confident detection of signals. Using data from initial LIGO's sixth science run, we show that the new analysis reduces the background noise in the search, giving a 30% increase in sensitive volume for binary neutron star systems over previous searches.Comment: 29 pages, 7 figures, accepted by Classical and Quantum Gravit

The updated DESGW processing pipeline for the third LIGO/VIRGO observing run

The DESGW group seeks to identify electromagnetic counterparts of gravitational wave events seen by the LIGO-VIRGO network, such as those expected from binary neutron star mergers or neutron star-black hole mergers. DESGW was active throughout the first two LIGO observing seasons, following up several binary black hole mergers and the first binary neutron star merger, GW170817. This work describes the modifications to the observing strategy generation and image processing pipeline between the second (ending in August 2017) and third (beginning in April 2019) LIGO observing seasons. The modifications include a more robust observing strategy generator, further parallelization of the image reduction software and difference imaging processing pipeline, data transfer streamlining, and a web page listing identified counterpart candidates that updates in real time. Taken together, the additional parallelization steps enable the identification of potential electromagnetic counterparts within fully calibrated search images in less than one hour, compared to the 3-5 hours it would typically take during the first two seasons. These performance improvements are critical to the entire EM follow-up community, as rapid identification (or rejection) of candidates enables detailed and rapid spectroscopic follow-up by multiple instruments, leading to more information about the environment immediately following such gravitational wave events

The updated DESGW processing pipeline for the third LIGO/VIRGO observing run

The DESGW group seeks to identify electromagnetic counterparts of gravitational wave events seen by the LIGO-VIRGO network, such as those expected from binary neutron star mergers or neutron star-black hole mergers. DESGW was active throughout the first two LIGO observing seasons, following up several binary black hole mergers and the first binary neutron star merger, GW170817. This work describes the modifications to the observing strategy generation and image processing pipeline between the second (ending in August 2017) and third (beginning in April 2019) LIGO observing seasons. The modifications include a more robust observing strategy generator, further parallelization of the image reduction software and difference imaging processing pipeline, data transfer streamlining, and a web page listing identified counterpart candidates that updates in real time. Taken together, the additional parallelization steps enable the identification of potential electromagnetic counterparts within fully calibrated search images in less than one hour, compared to the 3-5 hours it would typically take during the first two seasons. These performance improvements are critical to the entire EM follow-up community, as rapid identification (or rejection) of candidates enables detailed and rapid spectroscopic follow-up by multiple instruments, leading to more information about the environment immediately following such gravitational wave events

ligo-cbc/pycbc: O2 Production Release 9

This is the ninth production release for O2. It is based on the 1.6.7 release and implements several changes since the previous release. The following bug-fixes are implemented: https://github.com/ligo-cbc/pycbc/pull/1482 improves the reporting of version information from executables and https://github.com/ligo-cbc/pycbc/pull/1487 fixes the way that version information is reported in section 8 of the PyCBC results page. https://github.com/ligo-cbc/pycbc/pull/1483 adds a default segment_definer version number (1) to the segment files written by workflow generation scripts, so that these files can be queried by the standard glue segment tools. https://github.com/ligo-cbc/pycbc/pull/1488 adds the -p option when initializing a proxy with ligo-proxy-init to create an RFC compliant proxy needed to access frame data under CVMFS. It also removes the time restriction when generating an RFC compliant proxy from an non-RFC compliant one. https://github.com/ligo-cbc/pycbc/pull/1475 fixes the XML files uploaded to GraceDB. Two new features are also implemented: https://github.com/ligo-cbc/pycbc/pull/1484 implements a --config-delete in the workflow generation scripts. This allows a section or an option to be deleted from parsed configuration files before --config-overrides are applied. https://github.com/ligo-cbc/pycbc/pull/1470 and https://github.com/ligo-cbc/pycbc/pull/1476 implement the sine-gaussian veto test in pycbc_inspiral and allow it's use in the rest of the workflow. This code change requires changes to the configuration files to implement it. These changes are merged into the 1.6.8 configuration files. To revert the all-sky coincident search to the previous 1.6.7 behavior without the sine-Gaussian veto, use the following --config-overrides options when running pycbc_make_coinc_search_workflow:--config-overrides "fit_by_template:sngl-stat:new_snr" "coinc:ranking-statistic:phasetd_exp_fit_stat" "singles_minifollowup:ranking-statistic:newsnr" "page_snglinfo:ranking-statistic:newsnr" "plot_singles-endtime_duration_newsnr:z-var:'max(newsnr)'" "plot_singles-mtotal_effspin_newsnr:z-var:'max(newsnr)'" "plot_singles-duration_effspin_newsnr:z-var:'max(newsnr)'" "plot_singles-eta_effspin_newsnr:z-var:'max(newsnr)'" "plot_singles-mtotal_eta_newsnr:z-var:'max(newsnr)'" and the following --config-delete options:--config-delete "inspiral:sgchisq-snr-threshold" "inspiral:sgchisq-locations" The release is compatible with configuration files from https://code.pycbc.phy.syr.edu/ligo-cbc/pycbc-config/tree/v1.6.8/O2/pipeline This release has been tested against LALSuite with the hash a2a5a476d33f169b8749e2840c306a48df63c936 On a machine with CVMFS installed, a pre-built virtual environment is available for Red Hat 7 compatible operating systems by running the command: source /cvmfs/oasis.opensciencegrid.org/ligo/sw/pycbc/x86_64_rhel_7/virtualenv/pycbc-v1.6.8/bin/activate A bundled pycbc_inspiral executable for use on the Open Science Grid is available at /cvmfs/oasis.opensciencegrid.org/ligo/sw/pycbc/x86_64_rhel_6/bundle/v1.6.8/pycbc_inspira

ligo-cbc/pycbc: O2 Production Release 7

This is the sixth production release for O2. It is based on the 1.6.4 release and contains a bug fix needed for Pegasus 4.7.4 and a fix to the instructions for OSG running. This release also contains the Einstein@Home build infrastructure for building PyInstaller bundles. The release is compatible with configuration files from https://code.pycbc.phy.syr.edu/ligo-cbc/pycbc-config/tree/v1.6.6/O2/pipeline This release has been tested against LALSuite with the hash a2a5a476d33f169b8749e2840c306a48df63c936 On a machine with CVMFS installed, a pre-built virtual environment is available for Red Hat 7 compatible operating systems by running the command: source /cvmfs/oasis.opensciencegrid.org/ligo/sw/pycbc/x86_64_rhel_7/virtualenv/pycbc-v1.6.6/bin/activate A bundled pycbc_inspiral executable for use on the Open Science Grid is available at /cvmfs/oasis.opensciencegrid.org/ligo/sw/pycbc/x86_64_rhel_6/bundle/v1.6.6/pycbc_inspira

Search for intermediate mass black hole binaries in the first observing run of Advanced LIGO

International audienceDuring their first observational run, the two Advanced LIGO detectors attained an unprecedented sensitivity, resulting in the first direct detections of gravitational-wave signals produced by stellar-mass binary black hole systems. This paper reports on an all-sky search for gravitational waves (GWs) from merging intermediate mass black hole binaries (IMBHBs). The combined results from two independent search techniques were used in this study: the first employs a matched-filter algorithm that uses a bank of filters covering the GW signal parameter space, while the second is a generic search for GW transients (bursts). No GWs from IMBHBs were detected; therefore, we constrain the rate of several classes of IMBHB mergers. The most stringent limit is obtained for black holes of individual mass 100  M⊙, with spins aligned with the binary orbital angular momentum. For such systems, the merger rate is constrained to be less than 0.93  Gpc−3 yr−1 in comoving units at the 90% confidence level, an improvement of nearly 2 orders of magnitude over previous upper limits