[PDF] Multimessenger Astronomy With Low Latency Searches For Transient Gravitational Waves eBook

Author : Patrick Godwin
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Page : pages
File Size : 12,78 MB
Release : 2020
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August 8, 2017 marked the dawn of multi-messenger astronomy with the detection of gravitational waves from a binary neutron star merger from LIGO and Virgo, GW170817, and its joint detection of a short gamma ray burst observed by Fermi- GBM and INTEGRAL. This prompted a massive follow-up campaign with more than 70 telescopes and observatories participating in the search for multiple cosmic messengers from electromagnetic radiation, gravitational waves, cosmic rays and neutrinos. Being able to send out prompt alerts from gravitational wave detections is of utmost importance to capture the onset of electromagnetic emission from compact binary mergers, and this requires the rapid validation of gravitational-wave candidate events. While both LIGO-Hanford and LIGO-Livingston were operating at the time of the detection, a non-Gaussian noise transient, or glitch, coincided with the binary neutron star merger in LIGO-Livingston, causing the candidate event to be identified in low latency in only a single detector by the GstLAL analysis, a matched filter gravitational-wave search. The presence of non-Gaussian noise caused issues in the initial detection of the gravitational-wave signal, and signifies a need to provide rapid data quality information that can identify non-Gaussian noise transients and limit their impact in low-latency gravitational-wave searches. This dissertation focuses on methods to provide near-real-time data quality information and its incorporation into gravitational-wave searches. This includes a method to extract non-stationary noise features and using these features to perform real-time statistical inference of non-stationary noise in gravitational-wave data. Finally, I describe a procedure to incorporate statistical data quality information into the GstLAL search analysis, providing a way to autonomously folding in data quality information using the detector's auxiliary state for a wide set of glitch classes.

Author : Ryan Christopher Lynch
Publisher :
Page : 238 pages
File Size : 19,91 MB
Release : 2018
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Between 2015 and 2017, the era of gravitational-wave (GW) astronomy began in a spectacular fashion. The Advanced-era GW detectors directly observed GW transients from two types of compact-binary sources: binary black holes (e.g., GW150914) and binary neutron stars (e.g., GW170817). Compact-binary sources are well-studied theoretically with well-understood strain waverforms, and thus their detections with Advanced LIGO-Virgo has led to an enormous number of physical insights. Nevertheless, we expect transient GW sources with waveforms that are not fully modeled or are too quiet to be fully resolved may contain an abundant wealth of physical richness in their own right. This thesis explores how to confidently establish poorly-modeled and poorly-resolved, i.e., "unmodeled", GW transients as detections. We first develop a search algorithm that can be used to detect short-duration GW transients of general signal morphology. This algorithm was one of two independent algorithms to first detect the first GW detection, GW150914, in low-latency. After establishing how GW transients of arbitrary morphology can be detected, we turn our attention to the detection of quiet GW signals that are not fully resolvable. We first explore the prospect of using multi-messenger astronomy to elevate low-significance GW candidates to the status of confident detections. Then, we develop a statistical consistency test that can be used to detect populations of poorly-resolved GW candidates. We apply the new search algorithm and new statistical consistency test to data obtained in the first and second observing runs of the Advanced Detector Era. We show that standard compact-binary sources, such as GW150914, can be detected confidently using these methods. Although no non-compact-binary GW transients are detected, we use these new tools to set the strictest upper limits to date on the rate-density of non-compact-binary GW transients. Finally, we turn our attention to how future improvements to the Advanced Detectors, such as squeezed-light injection, will impact the science done with GW transients.

Author : Cody Messick
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Page : pages
File Size : 24,75 MB
Release : 2019
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Gravitational waves, ripples in space-time that cause the physical distance between points to change in time, were first predicted by Albert Einstein in the early twentieth century. One of the most promising sources of gravitational waves was thought to be the merger of binary neutron stars, which were also believed to generate extremely energetic bursts of light known as gamma-ray bursts and an optical transient known as a kilonova. Large interferometers capable of measuring distances of 10^18 m were built to detect gravitational waves. My dissertation research has been focused on detecting gravitational waves rapidly for the purpose of searching for electromagnetic or other signals from merging neutron star binaries. I contributed to the first-ever detection of gravitational waves in 2015, and every detection since. My work to rapidly identify new gravitational wave detections led to the first joint multi-messenger detection made in 30 years on August 17, 2017, when gravitational waves from a binary neutron star merger were observed in coincidence with a short gamma-ray burst, which led astronomers around the world to point their instruments at the region of the sky where the signal was estimated to have came from in time to observe counterparts across several electromagnetic bands. In this dissertation I will discuss each of these historical detections and the analysis I co-developed and helped perform.

Author : Stephen R. Taylor
Publisher : CRC Press
Page : 172 pages
File Size : 12,32 MB
Release : 2021-11-23
Category : Mathematics
ISBN : 1000484769

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Nanohertz Gravitational Wave Astronomy explores the exciting hunt for low frequency gravitational waves by using the extraordinary timing precision of pulsars. The book takes the reader on a tour across the expansive gravitational-wave landscape, from LIGO detections to the search for polarization patterns in the Cosmic Microwave Background, then hones in on the band of nanohertz frequencies that Pulsar Timing Arrays (PTAs) are sensitive to. Within this band may lie many pairs of the most massive black holes in the entire Universe, all radiating in chorus to produce a background of gravitational waves. The book shows how such extra-Galactic gravitational waves can alter the arrival times of radio pulses emanating from monitored Galactic pulsars, and how we can use the pattern of correlated timing deviations from many pulsars to tease out the elusive signal. The book takes a pragmatic approach to data analysis, explaining how it is performed in practice within classical and Bayesian statistics, as well as the numerous strategies one can use to optimize numerical Bayesian searches in PTA analyses. It closes with a complete discussion of the data model for nanohertz gravitational wave searches, and an overview of the past achievements, present efforts, and future prospects for PTAs. The book is accessible to upper division undergraduate students and graduate students of astronomy, and also serves as a useful desk reference for experts in the field. Key features: Contains a complete derivation of the pulsar timing response to gravitational waves, and the overlap reduction function for PTAs. Presents a comprehensive overview of source astrophysics, and the dynamical influences that shape the gravitational wave signals that PTAs are sensitive to. Serves as a detailed primer on gravitational-wave data analysis and numerical Bayesian techniques for PTAs.

Author : David G. Blair
Publisher : Cambridge University Press
Page : 508 pages
File Size : 49,78 MB
Release : 2005-10-13
Category : Science
ISBN : 9780521021029

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This book introduces the concepts of gravitational waves within the context of general relativity. The sources of gravitational radiation for which there is direct observational evidence and those of a more speculative nature are described. He then gives a general introduction to the methods of detection. In the subsequent chapters he has drawn together the leading scientists in the field to give a comprehensive practical and theoretical account of the physics and technology of gravitational wave detection.

Author : Andrew Levan
Publisher :
Page : 250 pages
File Size : 24,79 MB
Release : 2018-12-21
Category : Science
ISBN : 9780750315005

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As the most powerful explosion that occurs in the universe, gamma-ray bursts (GRBs) are one of the most exciting topics being studied in astrophysics. Creating more energy than the Sun does in its entire lifetime, GRBs create a blaze of light that will outshine every other object visible in the sky, enabling us to measure galaxies that are several million years old.GRBs cover various areas of astronomy and interest in them reaches a wide range of fields. Andrew Levan explores the fascinating history of these astronomical occurrences and details our current understanding of GRBs. The science behind them is rapidly moving and this book examines the knowledge that we now have as well as the questions that are continually being raised. Predominantly aimed at PhD students and researchers in the area, Gamma-Ray Bursts addresses this captivating topic and outlines the principles and initial applications of a fascinating astronomical phenomena.

Author : Samuel Franco
Publisher :
Page : 0 pages
File Size : 25,83 MB
Release : 2014
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This thesis presents the results of the STAMPAS all-sky search for long transient gravitational waves in the 2005-2007 LIGO-Virgo data. Gravitational waves are perturbations of the space-time metric. The Virgo and LIGO experiments are designed to detect such waves. They are Michelson interferometers with 3 km and 4 km long arms, whose light output is altered during the passage of a gravitational wave.Until very recently, transient gravitational wave search pipelines were focused on short transients, lasting less than 1 second, and on binary coalescence signals. STAMPAS is one of the very first pipelines entirely dedicated to the search of long transient gravitational wave signals, lasting from 1s to O(100s).These signals originate, among other sources, from instabilities in protoneutron stars as a result of their violent birth. The standing accretion shock instability in core collapse supernovae or instabilities in accretion disks are also possible mechanisms for gravitational wave long transients. Eccentric black hole binary coalescences are also expected to emit powerful gravitational waves for several seconds before the final plunge.STAMPAS is based on the correlation of data from two interferometers. Time-frequency maps of the data are extracted, and significant pixels are clustered to form triggers. No assumption on the direction, the time or the form of the signals is made.The first STAMPAS search has been performed on the data from the two LIGO detectors, between 2005 and 2007. After a rigorous trigger selection, the analysis revealed that their rate is close to Gaussian noise expectation, which is a significant achievement. No gravitational wave candidate has been detected, and upper limits on the astrophysical rates of several models of accretion disk instability sources and eccentric black holes binary coalescences have been set. The STAMPAS pipeline demonstrated its capabilities to search for any long transient gravitational wave signals during the advanced detector era.Keywords: Gravitational waves, Interferometry, Long transients, Signal Processing, Accretion Disk Instabilities, Eccentric Black Hole Binaries.

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Page : pages
File Size : 50,40 MB
Release : 2016
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A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams.