scholarly journals Unmodelled clustering methods for gravitational wave populations of compact binary mergers

2019 ◽  
Vol 488 (3) ◽  
pp. 3810-3817 ◽  
Author(s):  
Jade Powell ◽  
Simon Stevenson ◽  
Ilya Mandel ◽  
Peter Tiňo
Keyword(s):  
Gravitational Wave ◽  
Gaussian Mixture ◽  
Difficult Case ◽  
Clustering Methods ◽  
Compact Binaries ◽  
Mass Distributions ◽  
Compact Binary ◽  
Binary Mergers ◽  
Spin Distributions ◽  
Mixture Model Clustering

ABSTRACT The mass and spin distributions of compact binary gravitational-wave sources are currently uncertain due to complicated astrophysics involved in their formation. Multiple sub-populations of compact binaries representing different evolutionary scenarios may be present amongst sources detected by Advanced LIGO and Advanced Virgo. In addition to hierarchical modelling, unmodelled methods can aid in determining the number of sub-populations and their properties. In this paper, we apply Gaussian mixture model clustering to 1000 simulated gravitational-wave compact binary sources from a mixture of five sub-populations. Using both mass and spin as input parameters, we determine how many binary detections are needed to accurately determine the number of sub-populations and their mass and spin distributions. In the most difficult case that we consider, where two sub-populations have identical mass distributions but differ in their spin, which is poorly constrained by gravitational-wave detections, we find that ∼400 detections are needed before we can identify the correct number of sub-populations.

scholarly journals Virgo and Gravitational-Wave Computing in Europe

2020 ◽  
Vol 245 ◽  
pp. 07050
Author(s):  
Stefano Bagnasco
Keyword(s):  
Gravitational Wave ◽  
Current Status ◽  
Low Latency ◽  
Observational Period ◽  
Compact Binaries ◽  
The Third ◽  
Compact Binary ◽  
Continuous Waves ◽  
The Us ◽  
Wave Event

Advanced Virgo is an interferometer for the detection of gravitational waves at the European Gravitational Observatory in Italy. Along with the two Advanced LIGO interferometers in the US, Advanced Virgo is being used to collect data from astrophysical sources such as compact binary coalescences and is currently running the third observational period, collecting gravitational wave event candidates at a rate of more than once per week. Data from the interferometer are processed by running search pipelines for several expected signals, from coalescing compact binaries to continuous waves and burst events. Furthermore, detector characterisation studies are run. Some of the processing needs to be done with low latency, to be able to provide triggers for other observatories and make multi-messenger observations possible. Deep searches are run offline on external computing centres. Thus, data needs also to be reliably and promptly distributed from the EGO site to computer centres in Europe and the US for further analysis and archival storage. Two of the defining characteristics of Virgo computing are the heterogeneity of the activities and the need to interoperate with LIGO. A very wide array of analysis pipelines differing in scientific target, implementation details and running environment assumptions have to be allowed to run ubiquitously and uniformly on dedicated resources and, in perspective, on heterogeneous infrastructures. The current status, possible strategies and outlook of Virgo computing are discussed.

scholarly journals A Joint Fermi-GBM and LIGO/Virgo Analysis of Compact Binary Mergers from the First and Second Gravitational-wave Observing Runs

2020 ◽  
Vol 893 (2) ◽  
pp. 100 ◽  
Author(s):  
R. Hamburg ◽  
C. Fletcher ◽  
E. Burns ◽  
A. Goldstein ◽  
E. Bissaldi ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Compact Binary ◽  
Binary Mergers

scholarly journals Prospects for gravitational-wave polarization tests from compact binary mergers with future ground-based detectors

2019 ◽  
Vol 100 (4) ◽  
Author(s):  
Hiroki Takeda ◽  
Atsushi Nishizawa ◽  
Koji Nagano ◽  
Yuta Michimura ◽  
Kentaro Komori ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Wave Polarization ◽  
Compact Binary ◽  
Binary Mergers

scholarly journals Kilonova/Macronova Emission from Compact Binary Mergers

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Masaomi Tanaka
Keyword(s):  
Gravitational Wave ◽  
Near Infrared ◽  
Expansion Velocity ◽  
Infrared Excess ◽  
Wave Source ◽  
Compact Binary ◽  
Binary Mergers ◽  
Infrared Wavelengths ◽  
Absolute Magnitudes ◽  
Review Current

We review current understanding of kilonova/macronova emission from compact binary mergers (mergers of two neutron stars or a neutron star and a black hole). Kilonova/macronova is emission powered by radioactive decays ofr-process nuclei and it is one of the most promising electromagnetic counterparts of gravitational wave sources. Emission from the dynamical ejecta of ~0.01M⊙is likely to have a luminosity of ~1040–1041 erg s−1with a characteristic timescale of about 1 week. The spectral peak is located in red optical or near-infrared wavelengths. A subsequent accretion disk wind may provide an additional luminosity or an earlier/bluer emission if it is not absorbed by the precedent dynamical ejecta. The detection of near-infrared excess in short GRB 130603B and possible optical excess in GRB 060614 supports the concept of the kilonova/macronova scenario. At 200 Mpc distance, a typical peak brightness of kilonova/macronova with0.01M⊙ejecta is about 22 mag and the emission rapidly fades to >24 mag within ~10 days. Kilonova/macronova candidates can be distinguished from supernovae by (1) the faster time evolution, (2) fainter absolute magnitudes, and (3) redder colors. Since the high expansion velocity (v~0.1–0.2c) is a robust outcome of compact binary mergers, the detection of smooth spectra will be the smoking gun to conclusively identify the gravitational wave source.

scholarly journals Low-Γ jets from Compact Binary Mergers as Candidate Electromagnetic Counterparts to Gravitational Wave Sources

2016 ◽  
Vol 12 (S324) ◽  
pp. 66-69
Author(s):  
Gavin P. Lamb ◽  
Shiho Kobayashi
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Ambient Medium ◽  
Radioactive Decay ◽  
Prompt Gamma ◽  
Late Time ◽  
Astrophysical Jets ◽  
Power Law Distribution ◽  
Compact Binary ◽  
Binary Mergers

AbstractCompact binary mergers, with neutron stars or neutron star and black-hole components, are thought to produce various electromagnetic counterparts: short gamma-ray bursts (GRBs) from ultra-relativistic jets followed by broadband afterglow; semi-isotropic kilonova from radioactive decay of r-process elements; and late time radio flares; etc. If the jets from such mergers follow a similar power-law distribution of Lorentz factors as other astrophysical jets then the population of merger jets will be dominated by low-Γ values. The prompt gamma-rays associated with short GRBs would be suppressed for a low-Γ jet and the jet energy will be released as X-ray/optical/radio transients when a shock forms in the ambient medium. Using Monte Carlo simulations, we study the properties of such transients as candidate electromagnetic counterparts to gravitational wave sources detectable by LIGO/Virgo. Approximately 78% of merger-jets result in failed GRB with optical peaks 14-22 magnitude and an all-sky rate of 2-3 per year.

scholarly journals Quantum expander for gravitational-wave observatories

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Mikhail Korobko ◽  
Yiqiu Ma ◽  
Yanbei Chen ◽  
Roman Schnabel
Keyword(s):  
Gravitational Wave ◽  
Laser Light ◽  
Low Frequency ◽  
Optical Resonators ◽  
High Signal ◽  
Quantum Uncertainty ◽  
Frequency Sensitivity ◽  
The Past ◽  
Compact Binary ◽  
Binary Mergers

AbstractThe quantum uncertainty of laser light limits the sensitivity of gravitational-wave observatories. Over the past 30 years, techniques for squeezing the quantum uncertainty, as well as for enhancing gravitational-wave signals with optical resonators have been invented. Resonators, however, have finite linewidths, and the high signal frequencies that are produced during the highly scientifically interesting ring-down of astrophysical compact-binary mergers still cannot be resolved. Here, we propose a purely optical approach for expanding the detection bandwidth. It uses quantum uncertainty squeezing inside one of the optical resonators, compensating for the finite resonators’ linewidths while keeping the low-frequency sensitivity unchanged. This quantum expander is intended to enhance the sensitivity of future gravitational-wave detectors, and we suggest the use of this new tool in other cavity-enhanced metrological experiments.

scholarly journals Inferring the population properties of binary black holes from unresolved gravitational waves

2020 ◽  
Vol 496 (3) ◽  
pp. 3281-3290 ◽  
Author(s):  
Rory J E Smith ◽  
Colm Talbot ◽  
Francisco Hernandez Vivanco ◽  
Eric Thrane
Keyword(s):  
Black Holes ◽  
Gravitational Waves ◽  
Monte Carlo Study ◽  
Design Sensitivity ◽  
Spin Distribution ◽  
Binary Black Holes ◽  
Compact Binaries ◽  
Compact Binary ◽  
Binary Mergers ◽  
The Universe

ABSTRACT The vast majority of compact binary mergers in the Universe produce gravitational waves that are too weak to yield unambiguous detections; they are unresolved. We present a method to infer the population properties of compact binaries – such as their merger rates, mass spectrum, and spin distribution – using both resolved and unresolved gravitational waves. By eliminating entirely the distinction between resolved and unresolved signals, we eliminate bias from selection effects. To demonstrate this method, we carry out a Monte Carlo study using an astrophysically motivated population of binary black holes. We show that some population properties of compact binaries are well constrained by unresolved signals after about one week of observation with Advanced LIGO at design sensitivity.

scholarly journals Real-time Search for Compact Binary Mergers in Advanced LIGO and Virgo's Third Observing Run Using PyCBC Live

2021 ◽  
Vol 923 (2) ◽  
pp. 254
Author(s):  
Tito Dal Canton ◽  
Alexander H. Nitz ◽  
Bhooshan Gadre ◽  
Gareth S. Cabourn Davies ◽  
Verónica Villa-Ortega ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Frequency Domain ◽  
Rapid Identification ◽  
Matched Filtering ◽  
Low Latency ◽  
The Third ◽  
Compact Binary ◽  
Binary Mergers ◽  
And Performance

Abstract The third observing run of Advanced LIGO and Advanced Virgo took place between 2019 April and 2020 March and resulted in dozens of gravitational-wave candidates, many of which are now published as confident detections. A crucial requirement of the third observing run was the rapid identification and public reporting of compact binary mergers, which enabled massive follow-up observation campaigns with electromagnetic and neutrino observatories. PyCBC Live is a low-latency search for compact binary mergers based on frequency-domain matched filtering, which was used during the second and third observing runs, together with other low-latency analyses, to generate these rapid alerts from the data acquired by LIGO and Virgo. This paper describes and evaluates the improvements made to PyCBC Live after the second observing run, which defined its operation and performance during the third observing run.

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