Gravitational Wave Open Science Center

Data release for event GW170817

This page has been prepared by the LIGO Scientific Collaboration (LSC) and the Virgo Collaboration.

The event occurred at GPS time 1187008882.43 = August 17 2017, 12:41:04.43 UTC.

The event was observed by data from the LIGO Hanford (H1), LIGO Livingston (L1) and Virgo (V1) detectors.

Because the Binary Neutron Star signal spends much more than 32 seconds in the detector's frequency band, data products of 32 seconds in duration are not being distributed with GW170817.

This page serves as a supplement to the paper GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral, available from LIGO DCC and doi:10.1103/PhysRevLett.119.161101.


Gravitational-Wave Strain Data


Strain data after noise subtraction

After data collection, several independently-measured terrestrial contributions to the detector noise were subtracted from the LIGO data using Wiener filtering. This subtraction removed calibration lines and 60 Hz AC power mains harmonics from both LIGO data streams. At times near GW170817, the sensitivity of LIGO-Hanford was particularly improved by the subtraction of laser pointing noise; several broad peaks in the 150 - 800 Hz region were effectively removed, increasing the Binary Neutron Star horizon distance of that detector by 26%. In addition, a short instrumental noise transient appeared in the LIGO-Livingston detector 1.1 s before the coalescence time of GW170817. This transient noise, or glitch, produced a very brief (less than 5ms) saturation in a digital-to-analog converter. This glitch has been removed from the noise subtracted data. For reference:

Notes:

After noise subtraction, 4096 Hz H1 L1 V1
2048 seconds (event signal reaches peak amplitude 1842.43 seconds ± 30 msec from start†) hdf5 gwf txt.gz hdf5 gwf txt.gz hdf5 gwf txt.gz
After noise subtraction, 16384 Hz H1 L1 V1
2048 seconds (event signal reaches peak amplitude 1842.43 seconds ± 30 msec from start†) hdf5 gwf txt.gz hdf5 gwf txt.gz hdf5 gwf txt.gz

† The ± 30 msec window for peak amplitude is due to different arrival time in each of the three detectors.


Strain data before noise subtraction

These files contain data before noise subtraction. These data were produced in low-latency, and used by the search pipelines to evaluate event significance. A short instrumental noise transient appeared in the LIGO-Livingston detector 1.1 s before the coalescence time of GW170817. This transient noise, or glitch, produced a very brief (less than 5ms) saturation in a digital-to-analog converter. This glitch is present in the strain data before noise subtraction. To evaluate the significance of GW170817, the CBC search analyses applied a window function to zero out the data around the glitch. This Tukey window uses the following parameters: zero the data +/- 0.1 seconds (0.2 seconds total in length) around the glitch time 1187008881.389 and the roll-off time is 0.5 seconds either side of the zeroed data. This inverse Tukey window is presented in Figure 2 of the GW170817 discovery paper. Some Burst searches may use a CAT2 data quality flag to remove this glitch from search results. There is an active Burst CAT2 data quality flag at LIGO-Livingston starting at 1187008880 and extending to 1187008884. In this case also GEO600 data are released. The GEO600 calibration uncertainty is estimated to be within 15% in amplitude and 15 deg in phase in the 1-4 kHz band.

Notes:

Before noise subtraction, 4096 Hz H1 L1 V1 G1
4096 seconds (event signal reaches peak amplitude 2048.43 seconds ± 30 msec from start†) hdf5 gwf txt.gz hdf5 gwf txt.gz hdf5 gwf txt.gz hdf5 gwf txt.gz
Before noise subtraction, 16384 Hz H1 L1 V1 G1
4096 seconds (event signal reaches peak amplitude 2048.43 seconds ± 30 msec from start†) hdf5 gwf txt.gz hdf5 gwf txt.gz hdf5 gwf txt.gz hdf5 gwf txt.gz

† The ± 30 msec window for peak amplitude is due to different arrival time in each of the three detectors.


Sky Localization

Source localization data for GW170817 are available as LIGO G1701985

Rapid triggers from LIGO data are available as GCN notices for GW170817

Parameter Estimation Samples

Parameter estimation samples: P1800115 | P1800061


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