5/31/2023 0 Comments Cassiopeia s6![]() ![]() If we assume that the noise is stationary, so that it’s properties don’t change with time, we can simply describe the properties of the noise with the power spectral density. The different sources can affect different frequencies. There are many sources of noise for our detectors. This is may just contain noise,, or it may also contain a signal. The signal our detectors measure is a time series. I’ll leave talking about residuals to this bonus note, as it involves a long tangent and me needing to lie down for a while. My discussion of the GWOSC Paper goes into more detail on the basics of LIGO and Virgo data, and some details on calibration and data quality. I won’t summarise everything here, I want to focus the (roughly undergraduate-level) foundations of how we do our analysis in the frequency domain. The paper works through things thoroughly, and I would encourage you to work though it if you are interested. Residuals around GW150914-a consistency check that we have understood the noise surrounding our first detection.Inferring waveform and physical parameters-how we estimate the parameters of the source of a gravitational wave.Signal detection-how we identify times in the data which have a transient signal present.The noise model and likelihood-how we use our understanding of the noise, under the assumption of it being stationary, to work out the likelihood of different signals being in the data.Detector calibration and data quality-how we make sure we have good quality data.Time–frequency analysis and stationarity-how we check the stability of data from our detectors.Fourier analysis-how we go from time series to looking at the data in the as a function of frequency, which is the most natural way to analyse that data.The basics of detector noise-how we describe sources of noise in our data.The basics of LIGO and Virgo data-what it is the we analyse.An introduction to observations at the time of writing.How do we go from this time series to discoveries about the Universe’s black holes and neutron stars? This paper gives the outline, it covers (in order) Well, they measure that, plus a whole lot of noise. They record a simple time series of the stretching and squeezing of space as a gravitational wave passes. Gravitational-wave detectors measure ripples in spacetime. Read this if: You want an introduction to signal analysisįavourite part: This is a great resource for new students If you do use data from GWOSC, please remember to say thank you. The paper specifically looks at the data released for our first and second observing runs ( O1 and O2), however, GWOSC also host data from the initial detectors’ fifth science run ( S5) and sixth science run ( S6), and will be updated with new data in the future. This paper outlines how these data are produced, going from our laser interferometers to your hard-drive. If you want to try analysing our delicious data yourself, either searching for signals or studying the signals we have found, GWOSC is the place to start. LIGO science summary: Open data from the first and second observing runs of Advanced LIGO and Advanced Virgoĭata from the LIGO and Virgo detectors is released by the Gravitational Wave Open Science Center (GWOSC, pronounced, unfortunately, as it is spelt). Website: Gravitational Wave Open Science Center Title: Open data from the first and second observing runs of Advanced LIGO and Advanced Virgo If you are new to the area, where should you start? Don’t panic! For the binary sources discovered so far, this Data Analysis Guide has you covered. There are now hundreds of papers on various aspects of gravitational-wave analysis. ![]() Similarly, gravitational-wave data analysis has developed over many decades-I’d say LIGO analysis was really kicked off in the early 1990s by Kipp Thorne’s group. It took many decades to develop the technology necessary to build gravitational-wave detectors. LIGO science summary: A guide to LIGO-Virgo detector noise and extraction of transient gravitational-wave signals Tutorial notebook: GitHub Google Colab Binder Title: A guide to LIGO-Virgo detector noise and extraction of transient gravitational-wave signals If you’d like a more in-depth understanding, I’d recommend visiting your local library for Michele Maggiore’s Gravitational Waves: Volume 1. These papers together should give you a good grounding in how to get started working with gravitational-wave data. ![]() In this post, I’ll share some of the resources made by LIGO and Virgo to help introduce gravitational-wave analysis. Understanding how to analyse the data can be tricky. If you’re a student looking for a project, a teacher planning a class activity, or a scientist working on a paper, this data is waiting for you to use. LIGO and Virgo make their data open for anyone to try analysing. ![]()
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