Artist's sketch of accreting neutron star, a possible source of gravitational waves. Image: NASA.
Accessing LIGO data
LIGO strain data from Hanford (H1) and Livingston (L1) detectors is stored in .GWF files on the CIT computer cluster. In MATLAB software used by LIGO Stochastic group, i.e. STAMP or Stochastic.m, we need the following:
- A job file: list of time segments of data.
Typical job file has 4 columns: some arbitrary index number, GPS start time (sec), GPS end time (sec), duration (sec)
Job files can be generated by this script: /home/boris.goncharov/jobgen/make-job-file.sh
- Frame files: list of files with paths to .GWF files for our jobs
Cache files can be generated by this perl script: /home/boris.goncharov/jobgen/cachefiles.pl
LIGO PSD and ASD
After taking a Fourier transform of LIGO strain data we get power-spectral density (PSD).
It has units [strain^2 / Hz].
After taking a square root of PSD we get amplitude spectral density (ASD).
It has units [strain / sqrt(Hz)]
Artist's representation of a GRB jets (NASA), and a 3D model of the Lomonosov satellite (MSU).