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.
- There is more information about this event in a companion paper "Binary Black Hole Mergers in the first Advanced LIGO Observing Run", which is available from LIGO DCC.
- There is more open data about this event, in the files attached to the above paper in the LIGO DCC.
- There are Science Summaries, covering the information below in ordinary language.
- This dataset has the Digital Object Identifier (doi) https://doi.org/10.7935/K5H41PBP
- There are tutorials to work with the strain data.
- There is a one page factsheet about GW151226, summarizing the event.
- There is a technical details page about the data linked below, and feel free to contact us.
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.
- Data usage notes: Please Read This First!
- The data are provided in three formats. HDF5 , Frame (.gwf), and gzipped ascii text. Many data analysis environments can read in data from HDF5 files, including Python (see the h5py package), MATLAB, C/C++, and IDL.
- The md5 checksums provide a check for downloaders that they have received the right file: run the Unix command "md5" (or "md5sum", depending on your OS) on your file and compare to LOSC published values. If different, try downloading again, and if the problem persists, contact us.
- Technical details especially about data quality and injections
- Tutorials to work with the strain data.
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:
- Visualize the source sky localization estimated from LIGO observations.
The skymap is represented as HEALPIX-FITS files in equatorial frame, available gzipped:
- LALInference final FITS DATA
- BAYESTAR low latency FITS DATA
- CWB low latency FITS DATA
- LALInference initial FITS DATA
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.
- Hanford data
- Livingston data
- Best-fit template
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.