Gravitational Wave Followup Events

Run
Event
Type

IMPORTANT: All names that begin with "MS" are mock/test events ("Mock Superevent"; only the 5 latest will be displayed).
Only names that begin with "GW" or "S" are possible real GW events ("Superevent").
For more information, see the Gravitational Wave Candidate Event Database.↗


Note: The NED and Census of the Local Universe (CLU) projects are issuing a joint notice of candidate galaxies for each GW trigger. While a large fraction of the galaxies in CLU catalog come from NED, there are galaxies in CLU that have not yet been ingested into NED, and NED is continually updating its holdings. Thus, some of the CLU top 20 galaxies listed in the GCN notices may not be in the NED list on this website. In addition, the NED service sorts its galaxies differently than CLU. However, the overall composition of the CLU and NED galaxy lists will be similar.


Sky Localization for S250223fw-2-Preliminary Cross-Matched with Galaxies in NED

At the time of the alert, this event was beyond the distance supported by this service (1000 Mpc).

GW Event Information Table columns: graceID is the International Gravitational-Wave Observatory Network (IGWN) designation and is a link to the GraceDB entry for this event. EventDate is the date and time of the GW event in UTC. Distance is the mean and standard devation of the event. Instruments indicates which facilities were involved in detecting the GW event. Classification indicates if the source has a significant probability (>10%) of BNS, NSBH, BBH, and Terrestrial; see Content page↗ for details) dervied by the IGWN pipeline. HasNS, HasRemnant, and HasMassGap are the probabilities that at least one of the compact objects was a neutron star, that the system ejected a non-zero amount of neutron star matter, and that at least one of the compact objects has mass in the range 3-5 solar masses, respectively. FAR is the false alarm rate for the GW event given as the number of instances per year that a noise fluctuation is expected to occur with the strength of this event in each of the detectors at the same time.
graceID↗ EventDate Distance (Mpc) Instruments Classification HasNS HasRemnant HasMassGap FAR
S250223fw 2025-02-23 18:18:00 (UTC) 4458.7 +/- 1613 H1,L1,V1 Terrestrial (80%), BBH (19%) 0.0 0.0 0.00411 203.71 per year
Last Update: 25-02-23 18:23:08 (UTC)