4. Calculating (and plotting) rate versus time for an
I would like to study the rate at which event triggers are generated by the
ExcessPower gravitational-wave burst detection algorithm, over a small
stretch of data.
The data from which these events were generated contain a simulated gravitational-wave signal, or hardware injection, used to validate the performance of the LIGO detectors and downstream data analysis procedures.
First, we import the
EventTable object and read in a set of events from
a LIGO_LW-format XML file containing a
from gwpy.table import EventTable events = EventTable.read('H1-LDAS_STRAIN-968654552-10.xml.gz', tablename='sngl_burst', columns=['peak', 'snr'])
Here we manually specify the
columns to read in order to optimise
read() operation to parse only the data we actually need.
We can calculate the rate of events (in Hertz) using the
rate = events.event_rate(1, start=968654552, end=968654562)
plot = rate.step() ax = plot.gca() ax.set_xlim(968654552, 968654562) ax.set_ylabel('Event rate [Hz]') ax.set_title('LIGO Hanford Observatory event rate for HW100916') plot.show()