Generic burst waveforms

Perhaps the simplest waveforms which Minke is able to produce are so-caled “generic” or “ad-hoc” burst waveforms. These waveform families include gaussian bursts, sine-gaussian wavelets, and white noise bursts.

Gaussian bursts

Perhaps the simplest conceivable model of a burst of gravitational waves is one where energy is emitted across a broadband range of frequencies over a fixed period of time, with a smooth rise and decay in amplitude. Such a source can be modelled as with a Gaussian function, and may be a suitable model for broadband sources, such as the core-bounce during a core-collapse abbr:sn.

In searches the model for such a signal is

\[h(t) = A \exp\left( - \frac{ (t - t_{0})^{2} }{ 2 \sigma^{2} } \right),\]

for a strain \(h\) at time \(t\), with an amplitude \(A\), central time \(t_{0}\) and duration \(\sigma\).

Minke supports Gaussian bursts using the minke.sources.Gaussian class.

class minke.sources.Gaussian(duration, hrss, time, sky_dist=<function uniform_sky>, seed=0)[source]

A class to represent a Gaussian injection.

Methods

generate_tail(self[, sampling, length, …])

Generate a “low frequency tail” to append to the end of the waveform to overcome problems related to memory in the waveform.

interpolate(self, x_old, y_old, x_new[, method])

Convenience funtion to avoid repeated code

parse_polarisation(self, polarisation)

Convert a string description of a polarisation to an ellipse eccentricity and an ellipse angle.

plot(self[, figsize])

Produce a plot of the injection.

table_type

alias of glue.ligolw.lsctables.SimBurstTable

Sine-Gaussian bursts

In addition to searching for broadband, time-constrained bursts of gravitational wave energy, some sources are expected to produce gravitational waves which are in a confined range of frequencies, in addition to being released over a short time-span.

Such a source can be approximated by a sinusoidal signal which is enveloped by a Gaussian rise and decay in amplitude.

The model used in gls:ligo searches for such signals is:

\[h(t) = A \exp \left[ \frac{ - 2(t - t_{0})^{2} \pi^{2} f^{2}}{Q^{2}} \right] \cos\left[ 2 \pi f (t - t_{0}) \right],\]

for a strain \(h\) at time \(t\), with \(A\) the amplitude of the signal, \(t_{0}\) its central time, \(Q\) the quality factor of the burst, and \(f\) is frequency.

class minke.sources.SineGaussian(q, frequency, hrss, polarisation, time, sky_dist=<function uniform_sky>, seed=0)[source]

A class to represent a SineGaussian injection.

Methods

generate_tail(self[, sampling, length, …])

Generate a “low frequency tail” to append to the end of the waveform to overcome problems related to memory in the waveform.

interpolate(self, x_old, y_old, x_new[, method])

Convenience funtion to avoid repeated code

parse_polarisation(self, polarisation)

Convert a string description of a polarisation to an ellipse eccentricity and an ellipse angle.

plot(self[, figsize])

Produce a plot of the injection.

table_type

alias of glue.ligolw.lsctables.SimBurstTable

Band-limited white noise bursts

Astrophysical processes are unlikely to produce emission at a single frequency, or with a smooth evolution of amplitude, and so searches are normally expected to be sensitive to band-limited white noise bursts, which consist of band-limited uncorrelated noise within a Gaussian amplitude envelope.

class minke.sources.WhiteNoiseBurst(duration, bandwidth, frequency, time, hrss=None, egw=None, sky_dist=<function uniform_sky>, seed=0)[source]

A class to represent a WNB injection.

Methods

generate_tail(self[, sampling, length, …])

Generate a “low frequency tail” to append to the end of the waveform to overcome problems related to memory in the waveform.

interpolate(self, x_old, y_old, x_new[, method])

Convenience funtion to avoid repeated code

parse_polarisation(self, polarisation)

Convert a string description of a polarisation to an ellipse eccentricity and an ellipse angle.

plot(self[, figsize])

Produce a plot of the injection.

table_type

alias of glue.ligolw.lsctables.SimBurstTable