Notes

tutorials and worked examples on gravitational-wave data analysis, mostly converted from Jupyter notebooks

data-access noise waveforms hierarchical-inference parameter-estimation

2024

Mar 1
Computing the autocovariance function of the LIGO-Virgo design noise spectrum Turn the LALSimulation design PSDs for LIGO and Virgo into time-domain autocovariance functions and check that the resulting covariance matrix is positive definite

2023

Jul 27
Fitting a hierarchical Gaussian model with NumPyro on a GPU The same KDE-smoothed hierarchical Gaussian fit as the CPU version, run with NUTS on a single CUDA device
Jul 27
Fitting a hierarchical Gaussian model with NumPyro on CPUs Infer the mean and width of a Gaussian population from per-event posterior samples with NumPyro, using a KDE to smooth the samples and parallel chains across CPU cores
May 22
Fitting a hierarchical Gaussian model with PyMC Infer the mean and width of a Gaussian population from per-event posterior samples with PyMC, using a KDE to smooth the samples
May 20
Downloading LIGO strain data in bulk from GWOSC Find, download and read a day of public LIGO strain around GW150914 from several GWOSC files, then split it into short noise-only segments while dealing with gaps
May 15
Retrieving the noise spectra used in LVK parameter estimation Locate the latest parameter-estimation release for an event in the GWOSC catalog and pull the per-detector PSDs out of the data file
Mar 6
A probability density for drawing injections in a selection-function study A vectorized density over masses, spins and redshift, with hard bounds, from which to draw injections for estimating a detection selection function
Mar 5
Downloading and reading LIGO strain data around GW150914 A short primer on gravitational-wave strain data, then download an hour of public LIGO data with wget, read it with h5py and chop it into noise-only segments
Feb 3
Simulating detector noise from a power spectral density Draw Gaussian noise for LIGO and Virgo from their design PSDs in the frequency domain, transform to the time domain and check the result with a Welch estimate

2022

Oct 10
Time-domain waveforms with LALSimulation and projection onto a detector Generate an NRSur7dq4 waveform with ChooseTDWaveform, window and Fourier transform it, and project it onto LIGO Hanford with antenna patterns and the geocenter time delay
Jun 29
Reading LVK parameter-estimation samples with h5py Download a GWTC-3 posterior release from Zenodo and read the samples directly with h5py, without PESummary
May 3
Simulating black-hole charge and spin posteriors Draw fake posteriors for black-hole charge and spin from a simple population model in polar coordinates that respects the cosmic-censorship bound
Apr 22
Frequency-domain waveforms with LALSimulation Generate an IMRPhenomD waveform with ChooseFDWaveform, plot its amplitude and phase, and inverse-Fourier transform it to the time domain