3. Plotting an EventTable
as 2-d tiles¶
I would like to study the event triggers 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
sngl_burst
table
from gwpy.table import EventTable
events = EventTable.read(
"H1-LDAS_STRAIN-968654552-10.xml.gz", tablename="sngl_burst",
columns=["peak", "central_freq", "bandwidth", "duration", "snr"])
Note
Here we manually specify the columns
to read in order to optimise
the read()
operation to parse only the data we actually need.
We can make a plot of these events as 2-dimensional tiles by specifying the x- and y-axis columns, and the widths in those directions:
plot = events.tile("peak", "central_freq", "duration", "bandwidth",
color="snr")
ax = plot.gca()
ax.set_yscale("log")
ax.set_ylabel("Frequency [Hz]")
ax.set_epoch(968654552)
ax.set_xlim(968654552, 968654552+10)
ax.set_title("LIGO-Hanford event tiles for HW100916")
ax.colorbar(clim=[1, 8], cmap="YlGnBu", label="Signal-to-noise ratio (SNR)")
plot.show()
(png
)
