[PDF] The Search For Compact Binary Coalescence In Association With Short Grbs With Ligo Virgo S5 Vsr1 Data eBook

Author : Melissa Anne Frei
Publisher :
Page : 156 pages
File Size : 30,84 MB
Release : 2011
Category :
ISBN :

GET BOOK

Compact binary coalescing systems: binary neutron stars, neutron star black hole pairs and binary black hole systems, represent promising candidates for gravitational wave first detection and have the potential to provide precise tests of the strong-field predictions of general relativity. Observations of binary black hole (BBH) systems will provide a wealth of information relevant to fundamental physics, astrophysics and cosmology. The search for such systems is a major priority of the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations. A major area of research within LIGO-Virgo analysis groups is incorporation of spin into the search template banks used for binary black hole systems. In this dissertation, I compare the injection efficiency and parameter recovery from three binary black hole searches. One of the searches presented here uses non-spinning templates and represents the standard LIGO search for binary black holes with total masses between 35 and 100M[circle with dot]. The other two use spin aligned and anti-aligned templates representing a future search for black hole binary systems with total masses between 35-100M[circle with dot]. One of the two spinning searches has the spin parameter set to zero, nonspinning, as a check of the spinning method. (Additionally the (anti- )aligned spin searches use a retooling of the standard pipeline taking advantage of a code base designed specifically to handle Advanced LIGO data.) All three searches were run on artificial data created by the Numerical Injection Analysis 2 collaboration (NINJA2) containing Gaussian noise and numerically generated signals modeling aligned and anti-aligned spinning binary black holes. I found that for the analyzed two weeks of data the three searches recover injections with nearly equal efficiency; however, the spinning search recovers the parameters of the injections more accurately than the non-spinning search. Specifically, the parameter recovery of the spins shows a correlation between the injected and recovered spins, and the addition of spin to the template bank improves the recovery of the signal-to-noise ratio and the chirp mass for an injected signal. While spin aligned situations are geometrically low probability configurations, there are plausible astrophysical effects that lead to alignment of spins prior to merger. Therefore my results show that the spin-aligned template bank search represents an improvement on the standard non-spinning search in the highmass region and should be pursued on real data.

Author : Pablo Barneo
Publisher : BOD GmbH DE
Page : 186 pages
File Size : 25,32 MB
Release : 2024-04-10
Category : Science
ISBN : 8411748979

GET BOOK

Since the first experimental evidence for the existence of gravitational waves in 2015, the amount of data in this scientific area has increased enormously. There has also been a great deal of interest in the scientific community in gravitational waves. The interferometers, used to capture these waves, need to achieve a high level of instrumental sensitivity to be able to detect and analyse the weak signals emitted by both distant sources of intrinsically high intensity and nearby sources of much lower intensity. High sensitivity is often accompanied by high levels of noise that difficult data analysis. In nowadays interferometers, large amounts of data are recorded with a high percentage of noise from which we attempt to extract the possible gravitational waves buried therein. In this dissertation we propose to use a denoising method based on the minimisation of the total variance of the time series that constitute the data. Known as the ROF method, it assumes that the largest contribution to the total variance of a function comes from noise. In this way, a minimisation of this variance should lead to a drastic reduction in the presence of noise. This denoising procedure helps to improve the detection and data quality of gravitational wave analysis. We have implemented two ROF-based denoising algorithms in a commonly used gravitational-wave analysis software package. The analysis package is known as coherent WaveBurst (cWB) and uses the excess energy from the coherence between data from two or more interferometers to find gravitational waves. The denoising methods are the one-step regularised ROF (rROF), and the iterative rROF procedure (irROF). We have tested both methods using events from the gravitational-wave catalogue of the first three observing periods of the LIGO-Virgo-KAGRA scientific collaboration. These events, named GW1501914, GW151226, GW170817 and GW190521, comprise different wave morphologies of compact binary systems injected at different noise quality levels.

Author : Samuel Franco
Publisher :
Page : 0 pages
File Size : 15,20 MB
Release : 2014
Category :
ISBN :

GET BOOK

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.

Author : Ryan Christopher Lynch
Publisher :
Page : 238 pages
File Size : 47,91 MB
Release : 2018
Category :
ISBN :

GET BOOK

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 : Stephen Hawking
Publisher : Cambridge University Press
Page : 712 pages
File Size : 14,15 MB
Release : 1987
Category : Science
ISBN : 9780521379762

GET BOOK

A collection of reviews by prominent researchers in cosmology, relativity and particle physics commemorates the 300th anniversary of Newton's Philosophiae Naturalis Principia Mathematica.

Author : Heather Kin Yee Fong
Publisher :
Page : pages
File Size : 46,43 MB
Release : 2018
Category :
ISBN :

GET BOOK

Detecting gravitational waves is just the start of the story; to understand their nature and the systems that emitted them, we develop methods to correctly recover signals and characterize their source properties. This thesis describes three topics in Advanced LIGO gravitational-wave data analysis, each addressing technical challenges in order to improve the detection and measurement of gravitational-wave signals from compact binary coalescences. In the first project, I present a set of numerical relativity simulations that track the coalescences of binary black holes. I describe the methods by which the simulations were performed, as well as the techniques used to evaluate their gravitational waveforms. A comprehensive error analysis concludes that the minimum overlap of numerical relativity waveforms is 99.97%. My second project improves one of Advanced LIGO's detection pipelines by deriving a source-dependent likelihood-ratio ranking statistic to rank incoming compact binary coalescence signals. Results show that using a source-dependent ranking statistic improves the pipeline's sensitive volume-time -- and therefore, its sensitivity -- for binary neutron stars detections by 6-16%. In my final project, I determine the detectability of precessing compact binaries, deriving an analytic model and then estimating quantitatively the fraction of detected events where precession is measurable by gravitational-wave detectors. My model is consistent with the lack of detectable precession from currently observed signals and indicates, in particular, that GW170817 was not emitted by a strongly precessing system.

Author : Ryan Magee
Publisher :
Page : pages
File Size : 33,97 MB
Release : 2021
Category :
ISBN :

GET BOOK

The detection of gravitational waves by Advanced LIGO in 2015 marked the start of a new era in astrophysics. These small ripples in space-time - first predicted in the early 20th century by Albert Einstein - encode properties of the progenitor system and provide a powerful new way to probe distant and extreme astrophysical environments. My dissertation focuses on contributions I have made in facilitating the multi-messenger detection of electromagnetically bright sources and using LIGO's observations (or lack thereof) to constrain models of the dark matter. I describe the motivation for Advanced LIGO searches for sub-solar mass ultracompact binaries, as well as two recent searches I carried out with the LIGO-Virgo Scientific Collaboration. No confident detections were made in these searches, but the null result allowed us to place the tightest contraint to date on a particular model of the dark matter. I also discuss my contributions to efforts to detect binary neutron stars. Although the first BNS detection, GW170817, was a model multi-messenger discovery, there remains much to be learned about the extreme environment of the coalescence that can only be resolved by additional, prompt observations. I describe a subthreshold search for BNS that aims to increase our catalog of joint discoveries by facilitating searches for temporal or spatial coincidence, as well as recent attempts to detect BNS prior to merger to enable prompt electromagnetic followup.