O3 Second-trend Data from Seismometers, Wind Speed Monitors, and Accelerometers

Data Set

Gravitational-wave detectors are complex instruments that generate large amounts of data per their observations. In addition to the main channel sensitive to spacetime strain, where gravitational-wave signals are observed, each LIGO detector has over 100,000 auxiliary channels that monitor the operation of each subsystem and the seismic, acoustic, and electromagnetic environment. These sensors are employed for monitoring, diagnosing, and controlling the instrument and its environment.

The two LIGO detectors, located in Hanford, WA, and Livingston, LA, each consist of a 4-km-long Michelson laser interferometer whose sensitivity is further enhanced using multiple internal laser cavities. The length and angular degrees of freedom for the individual laser cavities, as well as the interferometer as a whole, must be sensed and actively controlled in order to maintain operational stability for long observation periods.

This data set consists of a subset of these auxiliary channels from the environmental sensors collected during the O3 run at both the Livingston (L1) and the Hanford (H1) observatories. The time series Root-Mean-Squares (RMS) are calculated over one second intervals. Therefore, all the available time series in the data set have a sample rate of 1 Hz, regardless of the sensor's actual sample rate.

Channel Names

Each channel has a name using this structure: [IFO]:[SYSTEM]-[NAME].rms, where:

  • [IFO] is the instrument (e.g., H1 refers to LIGO Hanford)
  • [SYSTEM] is an acronym for the instrument subsystem (e.g., PEM means "Physical Environment Monitor")
  • [NAME] is a name describing the channel (often containing more acronyms).
  • .rms indicates that the data content is RMS of the raw recorded data

Channel List

This data set includes 190 channels from the LIGO Hanford and 212 channels from the LIGO Livingston that were used in O3 run (1 Apr. 2019-27 Mar. 2020) for IFO operation and data quality validation. The data set has a total size of 61 GB. This data set includes channels that were used to create data quality flags, to subtract instrumental noise from the strain data, and to measure the amount of correlated noise between the gravitational-wave detectors. A short description of each channel's physical meaning can be found in the Channel List. In addition, DCC-G1200071 includes a diagram of the LIGO optical layout, which could be helpful in understanding the channel naming conventions.

Channel List

Usage Notes

  • These data include a large number of channels, and are provided on a best-effort basis; please use them with caution.
  • Environmental sensors may be disconnected or inoperable at any given time. As such, some channels may contain zeros and/or nonsensical data at some or all times.
  • Some channels may be incorrectly calibrated or not calibrated.
  • Calibration factors in the channel list are provided for informational purposes, and may not be accurate in all cases.

Data Access

NDS2

Data may be accessed from a network data server (NDS2) using the NDS2 client or GWpy. The following code can be used to download data (substitute any channel name that is a part of this data release): 

from gwpy.timeseries import TimeSeries
data = TimeSeries.fetch('L1:ISI-GND_STS_HAM5_X_BLRMS_100M_300M.rms', start=1266624018, end=1266624618, host='nds.gwosc.org')

See the Data Access Example Code for additional examples.

Segments

Data are available at times when the LIGO detectors are marked ANALYSIS_READY

Download Segment Lists:

Data for a small amount of time are missing, due to various reasons. Data is not available during the following time segments (the start and stop times of each segment are listed as [start ... stop)):

  • Missing times for H1: 
     [[1266789600 ... 1266789705)]
  • Missing times for L1: 
      [[1258311000 ... 1258311548)
  [1268515800 ... 1268516284)]

Tutorials

Tutorials that show examples of different applications of this data set can be found in the Tutorials Git Repository.

References that describe the use of these channels

Additional references

DOI

This dataset has DOI: 10.7935/9yc2-5d96

Revision History

  • First release: December 11, 2024