6. Plotting segments for a
Confident detection of gravitational-wave signals is critically dependent on understanding the quality of the data searched. Alongside the strain h(t) data, GWOSC also releases a Data Quality state vector. We can use this to check on the quality of the data from the LIGO Livingston detector around GW170817.
First, we can import the
from gwpy.timeseries import StateVector
and download the state information surrounding GW170817:
data = StateVector.fetch_open_data( "L1", 1187008882 - 100, 1187008882 + 100, verbose=True, )
Finally, we make a
display the bit names inside the axes:
plot = data.plot(insetlabels=True) ax = plot.gca() ax.set_xscale('seconds', epoch=1187008882) ax.axvline(1187008882, color='orange', linestyle='--') ax.set_title('LIGO-Livingston data quality around GW170817') plot.show()
This plot shows that for a short time exactly overlapping with GW170817 there was a data quality issue recorded that would negatively impact a search for generic gravitational-wave transients (bursts). For more details on this _glitch_, and on how it was excised, please see the Science Summary for GW170817.