O3 Auxiliary Channel Data Release

Data Set

The LIGO instrument at each site uses a large number of sensors to track the state of both the instrument and the surrounding environment. A subset of those sensors (channels) are used as part of astrophysical analyses by the LIGO-Virgo-KAGRA collaboration. The particular subset of channels provided here has been used to remove additional noise from LIGO data or to improve the quality of the astrophysical analyses.

Channel Names

Each channel has a name using this structure: [IFO]:[SYSTEM]-[NAME], 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 Enviornment Monitor")
  • [NAME] is a name describing the channel (often containing more acronyms).

Channel List

This data set includes 40 channels from LIGO Hanford and 46 channels from LIGO Livingston, that were used in O3 astrophysical analyses. The data set has a total size of 13 TB. 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. Additional details about how each of these channels was used in the data analysis can be found in the Complete Channel List.

Data Access

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_ITMY_Z_BLRMS_30M_100M', start=1266624018, end=1266624618, host='losc-nds.ligo.org')

See the Data Access Example Code for additional examples.

This data release is also available via CernVM-FS, under the directory gwosc.osgstorage.org. If accessing large amounts of data, and/or working on a computing cluster, CernVM-FS is recommended as the preferred option for data access.


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 failures of the low-latency calibration pipeline. Data is not available during the following time segments (the start and stop times of each segement are listed as [start ... stop)):

  • Missing times for H1:
     [[1239130112 ... 1239134208)]
  • Missing times for L1:
     [[1247261568 ... 1247261824)
     [1266183936 ... 1266185600)
     [1267377472 ... 1267377600)
     [1267377664 ... 1267377728)
     [1267556672 ... 1267557056)
     [1267559296 ... 1267559424)
     [1267564160 ... 1267564480)
     [1268516633 ... 1268516672)]


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


This data release is the first of its kind. Is it useful for your research? How could it be improved? Please contact us with any feedback.

Revision History

  • Feb 21, 2023: First release