Gravitational Wave Open Science Center

S6 Compact Binary Coalescence Hardware Injections

Hardware Injections

During LIGO's 6th Science Run (S6), 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 S6. 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.

Tables of Injections

The links below provide a list of CBC hardware injections executed during S6. Each injection is listed with the following information:
  • GPS: The GPS time of the end of the injection, or the "merger" time, in GPS seconds
  • Mass1 / Mass2: The mass, in solar units, of each compact object
  • Dist: The distance to the simulated source in Mpc.
  • SNR_exp: The expected SNR of the injection.
  • SNR_act: The recovered SNR of the injection, as described in Shannon Wang's project report. SNRs from 1-5 are typical for times with no signal.
The expected SNR and actual SNR were calculated using 100 seconds of data centered on the planned injection time. In cases where these 100 seconds of data included some time not in science mode, a smaller time window was used. 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:

Lists of S6 CBC injections: H1 | 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 L1
  • The HW_CBC segment lists contain the CBC injections H1 L1
  • Discrepencies between the Timeline and Parameter lists are notes here: H1 L1

Blind Injections

A number of CBC blind injections and blind injection tests were made during S6. Their times are listed below. In addition, the approximate times of blind injections are listed in the tables of injections, with 0's listed for all other parameters.
  • [954431951, 954432079]
  • [966378206, 966378309]
  • [967021118, 967021221]
  • [967515158, 967515261]
  • [967818859, 967818962]
  • [968654461, 968654564]
The last in this list, on 2010 Sept 16, is the subject of an earlier open data release by LIGO, known as GW100916 or Big Dog.

Additional Injection Lists

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