Gravitational Wave Open Science Center

S5 Compact Binary Coalescence Hardware Injections

Hardware Injections

During LIGO's 5th Science Run (S5), 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.

Compact Binary Coalescence Injections

Compact Binary Coalescence (CBC) injections were added at planned times throughout S5. Each CBC injection used a Post-Newtonian waveform to approximate the signal expected from the inspiral of a binary neutron star system, a neutron star with a black hole, or a binary black hole. A spectrogram of a sample injetion can be seen in the image on this page.

Blind Injections

In addition to the CBC injections noted in the tables below, there were CBC "blind injections" in S5:

CBC Blind Injection: 873739911

Blind Injection Tests: 865120335 and 865143706

See also this introduction to blind injections.

Tables of Injections

The links below provide a list of CBC hardware injections executed during S5. Each injection is listed with the following information:
  • GPS: The approximate GPS time of the end of the injection, or the "merger" time, in GPS seconds
  • IFO: The interferometer
  • M1 / M2: The mass, in solar units, of each compact object
  • Distance: The distance to the simulated source in Mpc.
  • Log: A log message indicating the success of the injection
  • Exp_SNR: The expected SNR of the injection based on the planned input parameters and a measurement of the detecotr PSD near the injection time.
  • Rec_SNR: The recovered SNR of the injection, as measured in the GWOSC data set. SNRs from 1-4 are typical for times with no signal.
The expected SNR and actual SNR were calculated using 64 seconds of data centered on the planned injection time. In cases where this 64 seconds of data included some time not in science mode, this calculation was not performed. It is possible that an injection or a partial injection exists in the data at some of these times. See the Technical Details page for more information.

Links to tables of injections: H1 H2 L1

Timeline Segment Lists of Injections

In addition to the log files shown above, information about injection times is available in segment lists from the Timeline application.
  • The HW segment lists contain all Burst, CBC, and Stochastic injection times: H1 H2 L1
  • The HW segment lists contain a small number of injections not noted in the Burst or CBC logs: H1 H2 L1
  • The HW_CBC segment lists contains a list CBC injections, but is only defined for the first year of the S5 run.

Additional Injection Lists

More information on CBC hardware injections is avaialable on the Technical Details page.