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")

GWpy’s TimeSeries class provides an interface to the public GWOSC data in the fetch_open_data() method; to use it we need to first import the TimeSeries object:

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 for GW150914):

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()

(png)

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.