Data release for event GW151226

This page has been prepared by the LIGO Scientific Collaboration (LSC) and the Virgo Collaboration to inform the broader community about a confirmed astrophysical event observed by the gravitational-wave detectors, and to make the data around that time available for others to analyze.

The event occurred at GPS time 1135136350.65 = December 26 2015, 03:38:53.65 UTC. It was recovered with a network signal-to-noise ratio of 13 and a significance of greater than 5 sigma. The event was detected in data from the LIGO Hanford and LIGO Livingston observatories.

This page serves as a supplement to the paper "GW151226: Observation of Gravitational Waves from a 22 Solar-mass Binary Black Hole Coalescence" which is available from LIGO DCC.


Estimated Source Parameters

Quantity Value Upper/Lower error estimate Unit
Primary mass 14.2 +8.3 -3.7 M sun
Secondary mass 7.5 +2.3 -2.3 M sun
Chirp mass 8.9 +0.3 -0.3 M sun
Total mass 21.8 +5.9 -1.7 M sun
Final mass 20.8 +6.1 -1.7 M sun
Final spin 0.74 +0.06 -0.06
Radiated gravitational-wave energy 1.0 +0.1 -0.2 M sun c2
Peak luminosity 3.3 +0.8 -1.6 1056 erg/s
Luminosity distance 440 +180 -190 Mpc
Source redshift z 0.09 +0.03 -0.04

Gravitational-Wave Strain Data

The data from the observatories from which the science is derived.

Strain Data at 4096 Hz

Strain h(t) time series centered at GPS 1135136350

Hanford Livingston
32 seconds (event is 16.65 seconds from start) hdf5 gwf txt.gz hdf5 gwf txt.gz
4096 seconds (event is 122.65 seconds from start) hdf5 gwf txt.gz hdf5 gwf txt.gz

Strain Data at 16384 Hz

Strain h(t) time series centered at GPS 1135136350

Hanford Livingston
32 seconds (event is 16.65 seconds from start) hdf5 gwf txt.gz hdf5 gwf txt.gz
4096 seconds (event is 122.65 seconds from start) hdf5 gwf txt.gz hdf5 gwf txt.gz

GW151226: Observation of Gravitational Waves from a 22 Solar-mass Binary Black Hole Coalescence

This page shows open data from the above-named paper which is available from LIGO DCC

FIG. 2. Search results from the two binary coalescence searches using their respective detection statistics ρ_c (left) and ln L (right) with GW150914 removed in all cases.


Sky localization

Sky localization was provided at low-latency by the BAYESTAR and CWB pipelines, and later with LALInference. After all the data and calibration was finalized, the LALInference skymap was made again, and it is the "best" skymap, therefore we put it first.

The skymap can be visualized in an astronomical context:

The skymap is represented as HEALPIX-FITS files in equatorial frame, available gzipped:

A python library for reading such files is healpy. A very simple healpy code to work with LIGO-Virgo skymaps is here. A large number of simulated skymaps is available here and here.


Audio Files

These files are derived from the strain data above, through signal processing as defined in the tutorial notebook "Tutorial on Binary Black Hole Signals in LIGO Open Data", that can be found in the tutorials section of this website.


About the Instruments and Collaborations

The LIGO Observatory

The Laser Interferometer Gravitational-Wave Observatory (LIGO) consists of two widely separated installations within the United States — one in Hanford, Washington and the other in Livingston, Louisiana — operated in unison as a single observatory. LIGO is operated by the LIGO Laboratory, a consortium of the California Institute of Technology (Caltech) and the Massachusetts Institute of Technology (MIT). Funded by the National Science Foundation, LIGO is an international resource for both physics and astrophysics.

The GEO600 Detector

The GEO600 project aims at the direct detection of gravitational waves by means of a laser interferometer of 600 m armlength located near Hannover, Germany. Besides collecting data for gravitational wave searches, the GEO600 detector has been used to develop and test advanced instrumentation for gravitational wave detection.

The LIGO Scientific Collaboration

The LIGO Scientific Collaboration (LSC) is a group of scientists seeking to make the first direct detection of gravitational waves, use them to explore the fundamental physics of gravity, and develop the emerging field of gravitational wave science as a tool of astronomical discovery. The LSC works toward this goal through research on, and development of techniques for, gravitational wave detection, and the development, commissioning and exploitation of gravitational wave detectors. The LSC carries out the science of the LIGO and GEO600 Observatories. Participation in the LSC is open to all interested scientists and engineers from educational and research institutions.


There is a technical details page about the data linked above, and feel free to contact us.