O1 Transient Hardware Injections
Hardware InjectionsDuring Advanced LIGO's first observing run (O1), simulated signals were added to the LIGO detectors for testing and calibration. The simulated signals are known as hardware injections, because they were created by manipulating mirrors in the arms of the interferometers. Times of hardware injections are marked in LIGO data files by injection data quality channels. See the injection bit mask definition for details.
Further details on hardware injections are in Validating gravitational-wave detections: The Advanced LIGO hardware injection system available from arXiv:1612.07864 [astro-ph.IM] and doi:10.1103/PhysRevD.95.062002.
Compact Binary Coalescence InjectionsCompact Binary Coalescence (CBC) injections were added at planned times throughout O1. Each CBC injection used a waveform to approximate the signal expected from the inspiral, merger, and ringdown of a binary neutron star system, a neutron star with a black hole, or a binary black hole. A spectrogram of a sample injection can be seen in the image on this page.
Burst InjectionsBurst injections include ad-hoc transient injections, as described for S6 burst injections.
Stochastic and Detector characterization InjectionsThese injections all happened in times when GWOSC does not have data, i.e. the DATA bit is off.
Tables of Transient InjectionsEach injection is listed with the following information:
Tables of transient injections:
Segment Lists when Injections are Not PresentIn addition to the log files shown above, information about injection-free times is available in segment lists from the Timeline application.
O1 Continuous Wave Hardware Injections
Continuous Wave Injections
Continuous Wave (CW) injections (also known as pulsar injections) were added throughout O1. Each CW injection corresponds to a simulation of a gravitational wave signal of the form expected from a rapidly rotating, isolated neutron star (often observed as a radio pulsar).
List of injected pulsar parameters: O1 pulsar injection parametersThe parameters are defined as in arxiv:0508096. The parameters f0 and phi0 are both defined at a reference time (epoch) which are chosen to be to either the beginning of LIGO's 3rd science run (S3, GPS 751680013 == 2003-11-01T00:00:00 UTC), or at the start of Virgo's 2nd run (VSR2, GPS 930582085 == 2009-07-02T15:01:10). Two additional parameters are also listed for each simulated pulsar:
Aplus = 0.5*h0*(1 + cos2(iota))
Across = h0*cos(iota)
For more information: