Event Portal Usage Notes
The Event Portal
provides an interface for finding strain data
for events discovered with LIGO and Virgo.
Catalogs are collections of events. You can see a listing of available catalogs on the
Catalog List page
Some events may be listed in the database with multiple version numbers. Different versions
of the same astrophysical event may differ in one or more of the following:
- Different versions of calibration applied to the associated strain data
- Different cleaning techniques applied to the associated strain data
- Different analysis results
- Different publications
You can see all versions for a given event by entering the event's name in the
Name Query Form
. For example, try searching for
Information for individual events
Individual event views (e.g. GW150914 v3
information about a given event entry. This includes:
- Documentation: Documentation or reference to give context for a given event.
- GPS: End time or merger time of the event in GPS seconds.
- GraceDB: If available, a link to the corresponding entry in
GraceDB, a database of
preliminary results from low-latency searches.
- GCN: Links to associated GCN notices and circulars,
used to communicate low-latency results at the time of discovery.
- Timeline: Link to segment and data quality information
- Notes: Technical notes. In many cases, this gives details about which
version of strain is included in this version.
Available strain data for the event are displayed on cards, with one card for each
detector with data available. Detectors do not run at all times, so any given event
may not have data from all detectors.
Each card includes:
- The detector code (H1 for Hanford, L1 for Livingston, V1 for Virgo, G1 for GEO)
- A time-frequency plot showing the Q-transform of a small segment of data,
centered on the merger time. These are proudced
Q-transform method in
gwpy. You can make similar plots using the
- Data download links for strain data available in different durations
(typically 32 seconds and 4096 seconds), different sampling frequencies (16384 Hz or
4096 Hz) and different file formats (GW frame files, HDF5, or ASCII text).
A number of notes about GWOSC event releases and their use may be seen on the
event release technical details page
Image on event portal home page is adopted from art by Aurore Simonnet at Sonoma State.