1. Accessing and visualising public GW detector data¶
Data from the current generation gravitational wave detectors are published by The Gravitational-Wave Open Science Centre (GWOSC) and freely available to the public. In this example we demonstrate how to identify times of a published GW detection event, and to download and visualise detector data.
Firstly, we can use the
gwosc Python package to query for the
time of the first gravitational-wave detection GW150914:
from gwosc.datasets import event_gps gps = event_gps("GW150914")
from gwpy.timeseries import TimeSeries
then call the
fetch_open_data() method, passing it the
prefix for the interferometer we want (
'L1' here for LIGO-Livingston),
and the GPS start and stop times of our query (based around the GPS time
data = TimeSeries.fetch_open_data('L1', gps-5, gps+5)
and then we can make a plot:
plot = data.plot( title="LIGO Livingston Observatory data for GW150914", ylabel="Strain amplitude", color="gwpy:ligo-livingston", epoch=gps, ) plot.show()
We can’t see anything that looks like a gravitational wave signal in these data, the amplitude is dominated by low-frequency detector noise. Further filtering is required to be able to identify the GW150914 event here, see Filtering a TimeSeries to detect gravitational waves for a more in-depth example of extracting signals from noise.