Simulates a gravitational waveform from black hole ringdown.

Synopsis

lalsim-bh-ringdown [-h] -M Msolar -a a -r distanceMpc -e fracEnergy -i inclination [-q azimuth] -l l -m m

Description

The lalsim-bh-ringdown utility produces a stream of a simulated gravitational waveform for ringdown radiation from a quasinormal mode of a Kerr black hole with mode numbers l and m. The dimensionless Kerr spin parameter a, black hole mass in solar masses Msolar, fraction of mass lost in ringdown radiation e, distance to the observer in Mpc distanceMpc, and inclination of the observer relative to the black hole's spin axis inclination must be specified. The output is written to standard output in three-column ascii format. The first column gives the time corresponding to each sample, the second column gives the value of the plus-polarization of the waveform, and the third column gives the value of the cross-polarization of the waveform.

Options

-h, --help: print a help message and exit
-M Msolar: (required) set black hole mass (solar masses)
-a a: (required) set value of dimensionless spin parameter a/M, |a/M|<1 (Leaver: |a/M|<0.5)
-r distanceMpc: (required) set distance (Mpc)
-e fracEnergy: (required) set energy radiated (fraction of mass)
-i inclination: (required) set inclination angle (degrees)
-q azimuth: (optional: default=0) set azimuth angle (degrees)
-l l: (required) set value of mode number l, l>=0
-m m: (required) set value of mode number m, abs(m)<=l

Environment

The LAL_DEBUG_LEVEL can used to control the error and warning reporting of lalsim-bh-ringdown. Common values are: LAL_DEBUG_LEVEL=0 which suppresses error messages, LAL_DEBUG_LEVEL=1 which prints error messages alone, LAL_DEBUG_LEVEL=3 which prints both error messages and warning messages, and LAL_DEBUG_LEVEL=7 which additionally prints informational messages.

Exit Status

The lalsim-bh-ringdown utility exits 0 on success, and >0 if an error occurs.

Example

The command:

lalsim-bh-ringdown -M 10 -a 0.97 -r 1.0 -e 0.01 -i 45.0 -l 2 -m 2

produces a three-column ascii output to standard output; the rows are samples (at the rate of 16384 Hz), and the three columns are 1. the time of each sample, 2. the plus-polarization strain, and 3. the cross-polarization strain. The waveform produced is for a 10 solar mass black hole spinning with Kerr parameter a/M = 0.97 at a distance of 1 Mpc and inclination of 45 degrees that radiates 1% of its mass in the l = 2, m = 2 quasinormal mode.