List of gravitational wave observations explained

This page contains a list of observed/candidate gravitational wave events.

Origin and nomenclature

Direct observation of gravitational waves, which commenced with the detection of an event by LIGO in 2015,^[1] plays a key role in gravitational wave astronomy. LIGO has been involved in all subsequent detections to date, with Virgo joining in August 2017.^[2]

Joint observation runs of LIGO and VIRGO, designated "O1, O2, etc." span many months, with months of maintenance and upgrades in-between designed to increase the instruments sensitivity and range. Within these run periods, the instruments are capable of detecting gravitational waves.

The first run, O1, ran from September 12, 2015, to January 19, 2016, and succeeded in its first gravitational wave detection. O2 ran for a greater duration, from November 30, 2016, to August 25, 2017.^[3] O3 began on April 1, 2019, which was briefly suspended on September 30, 2019, for maintenance and upgrades, thus O3a. O3b marks resuming of the run and began on November 1, 2019. Due to the COVID-19 pandemic^[4] O3 was forced to end prematurely. O4 began on May 24, 2023; initially planned for March, the project needed more time to stabilize the instruments.

The O4 observing run has been extended from one year to 18 months, following plans to make further upgrades for the O5 run.^[2] Updated observing plans are published on the official website, containing the latest information on these runs.^[5] There is a two month commissioning break planned from January to March 2024, after which observations will resume for the remainder of O4.^[6]

Gravitational wave events are named starting with the prefix GW, while observations that trigger an event alert but have not (yet) been confirmed are named starting with the prefix S.^[7] Six digits then indicate the date of the event, with the two first digits representing the year, the two middle digits the month and two final digits the day of observation. This is similar to the systematic naming for other kinds of astronomical event observations, such as those of gamma-ray bursts.

Probable detections that are not confidently identified as gravitational wave events are designated LVT ("LIGO-Virgo trigger"). Known gravitational wave events come from the merger of two black holes (BH), two neutron stars (NS), or a black hole and a neutron star (BHNS).^{[8] [9]} Some objects are in the mass gap between the largest predicted neutron star masses (Tolman–Oppenheimer–Volkoff limit) and the smallest known black holes.

List of gravitational wave events

+Confirmed events by distance

+Initial objects by mass

GW event and time (UTC)<	-- DIFFERENT COLORS ARE USED FOR DIFFERENT OBSERVING RUNS -->	Date published	Location area^[10] (deg^2)	Signal to Noise Ratio (SNR)	Luminosity distance (Mpc)^[11]	Energy radiated/c^2 (M☉) ^[12]	Chirp mass (M☉) ^[13]	Effective spin	Primary		Secondary		Remnant			Notes	Ref.
	Type								Mass (M☉)	Type	Mass (M☉)	Type	Mass (M☉)	Spin
GW150914 09:50:45	2016-02-11							BH		BH					First GW detection; first BH merger observed	^[14] ^[15] ^[16]
09:54:43	2016-06-15														Formerly candidate LVT151012; accepted as astrophysical since February 2019	^[17] ^[18]
GW151226 03:38:53	2016-06-15															^[19] ^[20]
GW170104 10:11:58	2017-06-01															^[21] ^[22]
GW170608 02:01:16	2017-11-16														Smallest BH progenitor masses to date	^[23]
GW170729 18:56:29	2018-11-30														Largest progenitor masses until GW190521	^[24]
GW170809 08:28:21	2018-11-30
GW170814 10:30:43	2017-09-27														First announced detection by three observatories; first polarization measurement	^[25] ^[26]
GW170817 12:41:04	2017-10-16											HMNS-BH	≤ 2.8		First NS merger observed in GW; first detection of EM counterpart (GRB 170817A; AT 2017gfo); nearest event to date	^[27] ^[28] ^[29]
GW170818 02:25:09	2018-11-30
GW170823 13:13:58	2018-11-30
GW190403_051519 2019-04-03 05:15:19	2022-05-11							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->				^[30]
GW190408_181802 2019-04-08 18:18:02	2020-10-27							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S190408an.	^[31]
GW190412 2019-04-12 05:30:44	2020-04-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			First possible observation of a merger of two black holes of very different masses. Originally designated S190412m.	^[32] ^[33]
GW190413_052954 2019-04-13	2020-10-27							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW190413_134308 2019-04-13	2020-10-27							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW190421_213856 2019-04-21	2020-10-27							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S190421ar.
GW190424_180648 2019-04-24 18:06:48	2020-10-27							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW190425 2019-04-25 08:18:05	2020-01-06							<	-- Primary type -->		<	-- Secondary type -->					Originally designated S190425z (z:26th trigger	UTC day), this trigger was detected by a single LIGO instrument (of three LVC stations), and is considered by some scientists to have been confirmed as a binary neutron star merger.^[34] It was published in 2020 that a gamma-ray burst was detected (GRB 190425) ~0.5 seconds after the LIGO trigger, lasting 6 seconds and bearing similarities to GRB170817 (such as weakness [most power in sub-100 keV, or soft [[X-rays]]) bands], elevated energetic photon background levels [signal exceeding background by less than a factor of 2], and similar differences from other transients classified as short GRBs). Confidence was established for interpretation of a set of peaks through a control interval of only 2 days prior to the LIGO-Livingston trigger in INTEGRAL Electronic anticoincidence, could not be corroborated by other instruments and wasn't initially noted as a significant event. Non-detection in other instruments may be a consequence of an Earth-occulted source as the Fermi telescope attempted follow-up.^[35]	^[36] ^[37]
GW190426_152155 2019-04-26 15:21:55	2020-10-27							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			The primary object, being between 3.4 and 9.6 solar masses, is either a black hole or an object in the mass gap. Originally designated S230426c.
GW190426_190642 2019-04-26 19:06:42	2022-05-11							<	-- Primary type -->		<	-- Secondary type -->		<	-- Finaly type -->
GW190503_185404 2019-05-03 18:54:04	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S230503bf.
GW190512_180714 2019-05-12 18:07:14	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S230512at.
GW190513_205428 2019-05-13 20:54:28	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S230513bm.
GW190514_065416 2019-05-14 06:54:16	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->
GW190517_055101 2019-05-17 06:54:16	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S190517h.
GW190519_153544 2019-05-19 15:35:44	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S190519bj.
GW190521 2019-05-21 03:02:29	2020-09-02			Location Area -->					<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S190521g. Largest progenitor masses to date.	^[38] ^[39]
GW190521_074359 2019-05-21 07:43:59	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S190521r.
GW190527_092055 2019-05-27 09:20:55	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->
GW190602_175927 2019-06-02 17:59:27	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S190602aq.
GW190620_030421 2019-06-20 03:04:21	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->
GW190630_185205 2019-06-30 18:52:05	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S190630ag.
GW190701_203306 2019-07-01 20:33:06	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S190701ah.
GW190706_222641 2019-07-06 22:26:41	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S190706ai.
GW190707_093326 2019-07-07 09:33:26	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S190707q.
GW190708_232457 2019-07-08 23:24:57	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->
GW190719_215514 2019-07-09 21:55:14	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->
GW190720_000836 2019-07-20 00:08:36	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S190720a.
GW190725_174728 2019-07-25 17:47:28	2022-05-11							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW190727_060333 2019-07-27 06:03:33	2020-10-27							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S190727h.
GW190728_064510 2019-07-28 06:45:10	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S190728q.
GW190731_140936 2019-07-31 14:09:36	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->
GW190803_022701 2019-08-03 02:27:01	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->
GW190805_211137 2019-08-05 21:11:37	2022-05-11							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->
GW190814 2019-08-14 21:11:18	2020-06-23							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			No optical counterpart was discovered despite an extensive search of the probability region. The mass of the lighter component is estimated to be 2.6 times the mass of the Sun, placing it in the mass gap between neutron stars and black holes.^[40]	^[41] ^[42] ^[43] ^[44] ^[45] ^[46] ^[47] ^[48] ^[49]
GW190828_063405 2019-08-28 06:34:05	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S190828j.
GW190828_065509 2019-08-28 06:55:09	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S190828l.
GW190909_114149 2019-09-09 11:41:49	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->
GW190910_112807 2019-09-10 11:28:07	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->
GW190915_235702 2019-09-15 23:57:02	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->			Originally designated S230915ak.
GW190916_200658 2019-09-16 20:06:58	2022-05-11							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->
GW190917_114630 2019-09-17 11:46:30	2022-05-11							<	-- Primary type -->		<	-- Secondary type -->		<	-- Primary type -->
GW190924_021846 2019-09-24 02:18:46	2020-10-27							<	-- Primary type -->		<	-- Secondary type -->		<	-- Primary type -->			The secondary component, being between 3.1 and 6.4 solar masses, is either a black hole or an object in the mass gap. Originally designated S230924h.
GW190925_232845 2019-09-25 23:28:45	2022-05-11							<	-- Primary type -->		<	-- Secondary type -->		<	-- Primary type -->
GW190926_050336 2019-09-26 05:03:36	2022-05-11							<	-- Primary type -->		<	-- Secondary type -->		<	-- Primary type -->
GW190929_012149 2019-09-29 01:21:49	2020-10-27							<	-- Primary type -->		<	-- Primary type -->		<	-- Primary type -->
GW190930_133541 2019-09-30 13:35:41	2020-10-27							<	-- Primary type -->		<	-- Secondary type -->		<	-- Primary type -->			The secondary component, being between 4.5 and 9.5 solar masses, is either a black hole or an object in the mass gap. Originally designated S190930s.
GW191103 2019-11-03 01:25:49	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->				^[50]
GW191105 2019-11-05 14:35:21	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S191105e.
GW191109 2019-11-09 01:07:17	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S191109d.
GW191113 2019-11-13 07:17:53	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW191126 2019-11-26 11:52:59	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW191127 2019-11-27 05:02:27	2021-11-17							<	-- Primary type -->		<	-- Primary type -->		<	-- Final type -->
GW191129 2019-11-29 13:40:29	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S191129u.
GW191204_110529 2019-12-04 11:05:29	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW191204_171526 2019-12-04 17:15:26	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S191204r.
GW191215 2019-12-15 22:30:52	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S191215w.
GW191216 2019-12-16 21:33:38	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S191216ap.
GW191219 2019-12-19 16:31:20	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			The event is unconfirmed due to difficulty accurately modelling the extreme mass ratio.
GW191222 2019-12-22 03:35:37	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S191222n.
GW191230 2019-12-30 18:04:58	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW200105 2020-01-05 16:24:26	2021-06-29							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			First event confirmed to be a black hole and neutron star merger. Originally designated S200105ae.	^[51] ^[52]
GW200112 2020-01-12 15:58:38	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S200112r.
GW200114 2020-01-14 02:08:08	2022-08-18							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S200114f. The event was initially published as an unmodeled gravitational wave burst, and different studies have offered conflicting interpretations. One study suggested it was a nearby high-mass black hole merger with component masses of and Msun which was poorly modeled because of its high mass.^[53] Another study interpreted it as a somewhat smaller black hole merger taking place at the same time as a detector glitch.^[54] Both studies conclude the signal is most likely a real event, and the latter model is included in the table.
GW200115 2020-01-15 04:23:09	2021-06-29							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Second event confirmed to be a black hole and neutron star merger. Originally designated S200115j.	^[55]
GW200128 2020-01-28 02:20:11	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S200128d.
GW200129 2020-01-29 06:54:58	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S200129m.
GW200202 2020-02-02 15:43:12	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW200208_130117 2020-02-08 13:01:17	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S200208q.
GW200208_222617 2020-02-08 22:26:17	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW200209 2020-02-09 08:54:52	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW200210 2020-02-10 09:22:54	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			The secondary component, being between 2.41 and 3.30 solar masses, is an object in the mass gap.
GW200216 2020-02-16 22:08:04	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW200219 2020-02-19 09:44:15	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S200219ac.
GW200220_061928 2020-02-20 06:19:28	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW200220_124850 2020-02-20 12:48:50	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW200224 2020-02-24 22:22:34	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S200224ca.
GW200225 2020-02-25 06:04:21	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S200225q.
GW200302 2020-03-02 01:58:11	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S200302c.
GW200306 2020-03-06 09:37:14	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW200308 2020-03-08 17:36:09	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW200311 2020-03-11 11:58:53	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S200311bg.
GW200316 2020-03-16 21:57:56	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->			Originally designated S200316bj.
GW200322 2020-03-22 09:11:33	2021-11-17							<	-- Primary type -->		<	-- Secondary type -->		<	-- Final type -->
GW2305292023-05-29 18:15:00	2024-04-05							<	-- Secondary type -->		<	-- Secondary type -->					Originally designated S230529ay. Was detected using only the LIGO Livingston detector. It provides strong support for the primary object to be within the mass gap.	^[56]

Candidate events and marginal detections

There is possible detection of nanohertz waves by observation of the timing of pulsars, but they have not been confirmed at the 5 sigma level of confidence, .^[57]

Marginal detections from O1 and O2

In addition to well-constrained detections listed above, a number of low-significance detections of possible signals were made by LIGO and Virgo. Their characteristics are listed below, only including detections with a <50% chance of being noise:

Candidate
event!rowspan=2

Detection time (UTC)	Date published	Luminosity distance (Mpc)^[58]	Detector ^[59]	False alarm rate (year)	Effective spin	Primary		Secondary		Probability of terrestrial noise	Notes	Ref
Type				Mass (M☉)		Type	Mass (M☉)
151205	2015-12-05 19:55:25	2019-10-11		H,L	0.61						0.47		^[60]
170121	2017-01-21 21:25:36	2019-04-15		H,L							<0.01		^[61]
170304	2017-03-04 16:37:53	2019-10-11		H,L	2.5						0.30
170402	2017-04-02 21:51:50	2019-10-21		H,L							0.32
170727	2017-07-27 01:04:30	2019-10-11		H,L	180						0.006
170817A	2017-08-17 03:02:46	2019-10-21		H,L,V	11.5						0.14		^[62]

Observation candidates from O3/2019

From observation run O3/2019 on, observations are published as Open Public Alerts to facilitate multi-messenger observations of events.^{[63] [64] [65]} Candidate event records can be directly accessed at the Gravitational-Wave Candidate Event Database (GraceDB).^[66] On 1 April 2019, the start of the third observation run was announced with a circular published in the public alerts tracker.^[67] The first O3/2019 binary black hole detection alert was broadcast on 8 April 2019. A significant percentage of O3 candidate events detected by LIGO are accompanied by corresponding triggers at Virgo.

False alarm rates are mixed, with more than half of events assigned false alarm rates greater than 1 per 20 years, contingent on presence of glitches around signal, foreground electromagnetic instability, seismic activity, and operational status of any one of the three LIGO-Virgo instruments. For instance, events S190421ar and S190425z weren't detected by Virgo and LIGO's Hanford site, respectively.

The LIGO/Virgo collaboration took a short break from observing during the month of October 2019 to improve performance and prepare for future plans, with no signals detected in that month as a result.^[68]

The Kamioka Gravitational Wave Detector (KAGRA) in Japan became operational on 25 February 2020,^[69] likely improving the detection and localization of future gravitational wave signals.^[70] However, KAGRA does not report their signals in real-time on GraceDB as LIGO and Virgo do, so the results of their observation run will likely not be published until the end of O3.

The LIGO-Virgo collaboration ended the O3 run early on March 27, 2020, due to health concerns from the COVID-19 pandemic.^{[71] [72]}

+Candidate detections from O3 by month

+O3 detections by distance

GW event	Detection time (UTC)<	-- DIFFERENT COLORS ARE USED FOR DIFFERENT OBSERVING RUNS -->	Date published -->	Location area^[73] (deg^2)	Luminosity distance (Mpc)^[74]	Detector ^[75]	False alarm Rate (Hz)	False alarm chance in O3^[76]	Classification<					--! colspan=2	Properties -->	Notes	Ref
		NS / NS ^[77]		NS / BH ^[78]					BH / BH ^[79]	Mass gap ^[80]	Terrestrial ^[81]	HasNS -->	HasRemnant -->
S190901ap	2019-09-01 23:31:01<	--	2019-04-25 -->			L,V		0.181	0.861	0.0	0.0	0.0	0.139		^[82]
S190910d	2019-09-10 01:26:19<	--	2019-09-10 -->			H,L		0.100	0.0	0.976	0.0	0.0	0.024		^[83]
S190910h	2019-09-10 08:29:58<	--	2019-09-10 -->			L		0.642	0.612	0.0	0.0	0.0	0.388	Detected by only the Livingston detector, resulting in a bad sky localization.	^[84]
S190923y	2019-09-23 12:55:59<	--	2019-09-23 -->			H,L		0.746	0.0	0.677	0.0	0.0	0.322		^[85]
S190930t	2019-09-30 14:34:07<	--	2019-09-30 -->			L		0.348	0.0	0.743	0.0	0.0	0.257	Detected by only the Livingston detector, resulting in a bad sky localization; last detection of the O3a run.	^[86]
S191205ah	2019-12-05 21:52:08<	--	2019-12-05 -->			H,L,V		0.290	0.0	0.932	0.0	0.0	0.068		^[87]
S191213g	2019-12-13 04:34:08<	--	2019-12-13 -->			H,L,V		0.631	0.768	0.0	0.0	0.0	0.232		^[88]
S200213t	2020-02-13 04:10:40<	--	2020-02-13 -->			H,L,V		0.401	0.629	0.0	0.0	0.0	0.371		^[89]

Observation candidates from O4/2023

On 15 June 2022, LIGO announced to start the O4 observing run in March 2023.^[90] As the date got closer, engineering challenges delayed the observing run to May 2023.^[91] An engineering run to assess the sensitivity of LIGO, Virgo, and KAGRA began in April, with the Hanford detector's first operations beginning on April 29,^[92] and the Livingston and Virgo detectors' first operations beginning on May 5.^[93]

On March 7, 2023, a gamma-ray burst compatible with a neutron star merger was detected by the Fermi telescope and named GRB 230307A. The burst, identified as being from a host galaxy approximately 296 Mpc away, would likely have only been marginally detected at best by LIGO if it had been operating at the time, as the detectors would only later achieve a sensitivity of 160 Mpc for neutron star mergers by O4's beginning, 3 months later.

Near the end of the engineering run on 15 May 2023, LIGO announced that O4 would be beginning on 24 May 2023, running for 20 months with up to 2 months of maintenance. The LIGO detectors initially failed to achieve the hoped for 160-190 Mpc sensitivity for neutron star mergers, but did achieve an improved 130-150 Mpc sensitivity over O3's 100-140 Mpc, later improving to nearly 160 Mpc for both detectors by late 2023. Virgo was found to have both a damaged mirror and other new, unknown noise sources, limiting its sensitivity to just 31-35 Mpc (similar to its performance during O2 in 2017, and lower than O3's 40-50 Mpc.) As a result, Virgo spent most of 2023 in commissioning, with a deadline of March 2024 to improve its sensitivity before joining O4. KAGRA achieved its planned 1 Mpc sensitivity before returning to commissioning in July, with plans to rejoin at an improved 10 Mpc sensitivity by early 2024. However, the 7.5 2024 Noto earthquake occurred on 1 January 2024 only 103km (64miles) from KAGRA, damaging the detector's sensitive instruments and delaying its development by at least several months.

On 18 May 2023, near the end of the engineering run and shortly before O4 proper, the first candidate gravitational wave event was detected. Four more were detected before the official beginning of the run. In October, LIGO announced a planned pause between January and March 2024, for a mid-run commissioning break intended to reduce noise and improve the uptime of the detectors.

The O4b run began in April 2024 with the addition of the Virgo detector at a sensitivity of 55 Mpc. The Livingston detector achieved an increased sensitivity of 170-175 Mpc, while the Hanford detector maintained its pre-break sensitivity of 155-160 Mpc. Due to a variety of factors including delays in technologies required for O5, the decision was made in June 2024 to extend O4 by several months to June 2025, with O5 expected to begin in late 2027 or early 2028.

+Candidate detections from O4 by month

+O4 detections by distance

GW event	Detection time (UTC)<	-- DIFFERENT COLORS ARE USED FOR DIFFERENT OBSERVING RUNS -->	Date published -->	Location area^[94] (deg^2)	Luminosity distance (Mpc)^[95]	Detector ^[96]	False Alarm Rate (Hz)	False Alarm chance in O4^[97] ^[98]	Classification<					--! colspan=2	Properties -->	Notes	Ref
		NS / NS ^[99]							NS / BH ^[100]	BH / BH ^[101]	Mass gap ^[102]	Terrestrial ^[103]	HasNS -->	HasRemnant -->
S230518h	2023-05-18 12:59:07<	--	2023-05-18 -->			H,L		0.018	0.0	0.864	0.037	0.0	0.099	1.0 -->	0.0 -->	Detected during the engineering phase, before the official start of O4.	^[104]
S230520ae	2023-05-20 22:48:41<	--	2023-05-20 -->			H,L		0.161	0.0	0.0		0.0	1.4e-7	0.0 -->	0.0 -->		^[105]
S230522a	2023-05-22 09:38:04<	--	2023-05-22 -->			L		0.448	0.0	0.0	0.99973	0.00071	0.00027	0.0 -->	0.0 -->		^[106]
S230522n	2023-05-22 15:30:32<	--	2023-05-22 -->			L		0.311	0.0	0.0	0.993	0.0041	0.0069	0.0 -->	0.0 -->		^[107]
S230601bf	2023-06-01 22:41:34<	--	2023-06-01 -->			H,L		9.6 10^−8	0.0	0.0		0.0022	6.4e-9	0.0 -->	0.0 -->		^[108]
S230605o	2023-06-05 06:53:43<	--	2023-06-05 -->			H,L		0.229	0.0	0.0	0.988	0.0	0.012	0.0 -->	0.0 -->		^[109]
S230606d	2023-06-06 00:43:05<	--	2023-06-06 -->			H,L		0.481	0.0	0.0	0.99928	0.0	0.00072	0.0 -->	0.0 -->		^[110]
S230608as	2023-06-08 20:50:47<	--	2023-06-08 -->			H,L		0.0078	0.0	0.0	0.99981	0.0	0.00019	0.0 -->	0.0 -->		^[111]
S230609u	2023-06-09 06:49:58<	--	2023-06-09 -->			H,L		0.438	0.0	0.0	0.961	0.0	0.038	0.0 -->	0.0 -->		^[112]
S230624av	2023-06-24 11:31:03<	--	2023-06-24 -->			H,L		0.526	0.0	0.0	0.953	0.0	0.047	0.0 -->	0.0 -->		^[113]
S230627c	2023-06-27 01:53:37<	--	2023-06-27 -->			H,L		0.018	0.0	0.365	0.354	0.251	0.030	0.00015 -->	0.0 -->		^[114]
S230628ax	2023-06-28 23:12:00<	--	2023-06-28 -->			H,L		0.018	0.0	0.0		0.0	2.4e-5	0.0 -->	0.0 -->		^[115]
S230630am	2023-06-30 12:58:06<	--	2023-06-30 -->			H,L		0.750	0.0	0.0	0.941	0.042	0.017	0.0 -->	0.0 -->		^[116]
S230630bq	2023-06-30 23:45:32<	--	2023-06-30 -->			H,L		0.358	0.0	0.00076	0.890	0.079	0.031	0.0 -->	0.0 -->		^[117]
S230702an	2023-07-02 18:54:53<	--	2023-07-02 -->			H,L		8.8 10^−5	0.0	0.0		0.0	2.8e-5	0.0 -->	0.0 -->		^[118]
S230704f	2023-07-04 02:12:11<	--	2023-07-04 -->			H,L		0.149	0.0	0.0	0.997	0.0	0.0026	0.0 -->	0.0 -->		^[119]
S230706ah	2023-07-06 10:43:33<	--	2023-07-06 -->			H,L		0.914	0.0	0.0	0.939	0.035	0.027	0.0 -->	0.0 -->		^[120]
S230707ai	2023-07-07 12:40:47<	--	2023-07-07 -->			H,L		0.546	0.0	0.0	0.951	0.0	0.049	0.0 -->	0.0 -->		^[121]
S230708t	2023-07-08 05:37:05<	--	2023-07-08 -->			H,L		0.917	0.0	0.0	0.973	0.0041	0.027	0.0 -->	0.0 -->		^[122]
S230708z	2023-07-08 07:18:59<	--	2023-07-08 -->			H,L		0.982	0.0	0.0	0.954	0.0041	0.046	0.0 -->	0.0 -->		^[123]
S230708cf	2023-07-08 23:09:35<	--	2023-07-08 -->			H,L		0.590	0.0	0.0	0.989	0.0	0.011	0.0 -->	0.0 -->		^[124]
S230709bi	2023-07-09 12:27:27<	--	2023-07-09 -->			H,L		0.161	0.0	0.0	0.997	0.0	0.0028	0.0 -->	0.0 -->		^[125]
S230723ac	2023-07-23 10:18:23<	--	2023-07-23 -->			H,L		0.953	0.0	0.0	0.867	0.0	0.133	0.0 -->	0.0 -->		^[126]
S230726a	2023-07-26 00:29:40<	--	2023-07-26 -->			L		2.2 10^−6	0.0	0.0		0.0	1.4e-7	0.0 -->	0.0 -->	Detected by only the Livingston detector, resulting in a bad sky localization.	^[127]
S230729z	2023-07-29 08:23:17<	--	2023-07-29 -->			H,L		0.177	0.0	0.0	0.942	0.055	0.0030	0.0 -->	0.0 -->		^[128]
S230731an	2023-07-31 21:53:07<	--	2023-07-31 -->			H,L		0.018	0.0	0.174	0.771	0.053	0.0022	0.0 -->	0.0 -->		^[129]
S230802aq	2023-08-02 11:33:59<	--	2023-08-02 -->			H		0.722	0.0	0.020	0.289	0.657	0.035	0.572 -->	0.0036 -->	The other component is a black hole. Detected by only the Hanford detector, resulting in a bad sky localization.	^[130]
S230805x	2023-08-05 03:42:49<	--	2023-08-05 -->			H,L		0.410	0.0	0.0	0.99975	0.0	0.00025	0.0 -->	0.0 -->		^[131]
S230806ak	2023-08-06 20:40:41<	--	2023-08-06 -->			H,L		0.156	0.0	0.0	0.997	0.0	0.0026	0.0 -->	0.0 -->		^[132]
S230807f	2023-08-07 20:50:45<	--	2023-08-07 -->			H,L		0.983	0.0	0.0	0.913	0.041	0.047	0.0 -->	0.0 -->		^[133]
S230811n	2023-08-11 03:21:16<	--	2023-08-11 -->			H,L		0.018	0.0	0.0		0.0	2.2e-5	0.0 -->	0.0 -->		^[134]
S230814r	2023-08-14 06:19:20<	--	2023-08-14 -->			H,L		0.937	0.0	0.0	0.932	0.0	0.068	0.0 -->	0.0 -->		^[135]
S230814ah	2023-08-14 23:09:01<	--	2023-08-14 -->			L		0.0	0.0	0.0		0.0	2.0e-14	0.0 -->	0.0 -->	Detected by only the Livingston detector, resulting in a bad sky localization.	^[136]
S230819ax	2023-08-19 17:19:10<	--	2023-08-19 -->			H,L		0.398	0.0	0.0	0.993	0.0	0.0072	0.0 -->	0.0 -->		^[137]
S230820bq	2023-08-20 21:25:15<	--	2023-08-20 -->			H,L		0.912	0.0	0.0	0.958	0.0	0.042	0.0 -->	0.0 -->		^[138]
S230822bm	2023-08-22 23:03:37<	--	2023-08-22 -->			H,L		0.773	0.0	0.0	0.939	0.042	0.019	0.0 -->	0.0 -->		^[139]
S230824r	2023-08-24 03:30:47<	--	2023-08-24 -->			H,L		0.00094	0.0	0.0		0.0	2.9e-5	0.0 -->	0.0 -->		^[140]
S230825k	2023-08-25 04:13:34<	--	2023-08-25 -->			H,L		0.128	0.0	0.0	0.939	0.059	0.0022	0.0 -->	0.0 -->		^[141]
S230831e	2023-08-31 01:54:14<	--	2023-08-31 -->			H,L		0.679	0.0	0.0	0.985	0.0073	0.015	0.0 -->	0.0 -->		^[142]
S230904n	2023-09-04 05:10:13<	--	2023-09-04 -->			H,L		0.121	0.0	0.0007	0.927	0.064	0.009	0.0020 -->	0.0 -->		^[143]
S230911ae	2023-09-11 19:53:24<	--	2023-09-11 -->			H		0.00011	0.0	0.0		0.0	3.6e-6	0.0 -->	0.0 -->	Detected by only the Hanford detector, resulting in a bad sky localization.	^[144]
S230914ak	2023-09-14 11:14:01<	--	2023-09-14 -->			H,L		0.050	0.0	0.0	0.992	0.0	0.0083	0.0 -->	0.0 -->		^[145]
S230919bj	2023-09-19 21:57:12<	--	2023-09-19 -->			H,L		0.018	0.0	0.0	0.99965	0.0	0.00035	0.0 -->	0.0 -->		^[146]
S230920al	2023-09-20 07:11:24<	--	2023-09-20 -->			H,L		0.018	0.0	0.0		0.0	1.1e-5	0.0 -->	0.0 -->		^[147]
S230922g	2023-09-22 02:03:44<	--	2023-09-22 -->			H,L		0.0	0.0	0.0		0.0	0.0	0.0 -->	0.0 -->		^[148]
S230922q	2023-09-22 04:06:58<	--	2023-09-22 -->			H,L		0.021	0.0	0.0		0.0	2.2e-5	0.0 -->	0.0 -->		^[149]
S230924an	2023-09-24 12:44:53<	--	2023-09-24 -->			H,L		0.018	0.0	0.0		0.0	1.9e-5	0.0 -->	0.0 -->		^[150]
S230927l	2023-09-27 04:37:29<	--	2023-09-27 -->			H,L		0.461	0.0	0.0	0.976	0.0	0.024	0.0 -->	0.0 -->		^[151]
S230927be	2023-09-27 15:38:32<	--	2023-09-27 -->			H,L		0.018	0.0	0.0	0.99966	0.0	0.00034	0.0 -->	0.0 -->		^[152]
S230928cb	2023-09-28 21:58:27<	--	2023-09-28 -->			H,L		0.053	0.0	0.0		0.0	2.8e-5	0.0 -->	0.0 -->		^[153]
S230930al	2023-09-30 11:07:30<	--	2023-09-30 -->			H,L		0.346	0.0	0.0	0.994	0.0041	0.0061	0.0 -->	0.0 -->		^[154]
S231001aq	2023-10-01 14:02:20<	--	2023-10-01 -->			H,L		0.248	0.0	0.0	0.996	0.0044	0.0040	0.0 -->	0.0 -->		^[155]
S231005j	2023-10-05 02:10:30<	--	2023-10-05 -->			H,L		0.842	0.0	0.0	0.978	0.0	0.022	0.0 -->	0.0 -->		^[156]
S231005ah	2023-10-05 09:15:49<	--	2023-10-05 -->			H,L		0.111	0.0	0.0	0.998	0.0041	0.0015	0.0 -->	0.0 -->		^[157]
S231008ap	2023-10-08 14:25:21<	--	2023-10-08 -->			H,L		0.084	0.0	0.0	0.9986	0.0	0.0014	0.0 -->	0.0 -->		^[158]
S231014r	2023-10-14 04:05:48<	--	2023-10-14 -->			H,L		0.448	0.0	0.0	0.992	0.0	0.0080	0.0 -->	0.0 -->		^[159]
S231020ba	2023-10-20 14:29:47<	--	2023-10-20 -->			H,L		0.070	0.0	0.076	0.851	0.066	0.0070	0.0 -->	0.0 -->		^[160]
S231020bw	2023-10-20 18:05:09<	--	2023-10-20 -->			H,L		0.020	0.0	0.0	0.99965	0.0	0.00035	0.0 -->	0.0 -->		^[161]
S231028bg	2023-10-28 15:30:06<	--	2023-10-28 -->			H,L		0.0	0.0	0.0		0.0	0.0	0.0 -->	0.0 -->		^[162]
S231029y	2023-10-29 11:15:08<	--	2023-10-29 -->			L		0.012	0.0	0.0	0.99977	0.0	0.00023	0.0 -->	0.0 -->	Detected by only the Livingston detector, resulting in a bad sky localization.	^[163]
S231102w	2023-11-02 07:17:36<	--	2023-11-02 -->			H,L		0.0	0.0	0.0		0.0	3.3e-16	0.0 -->	0.0 -->		^[164]
S231104ac	2023-11-04 13:34:18<	--	2023-11-04 -->			H,L		0.018	0.0	0.0020	0.988	0.0088	0.0018	0.0 -->	0.0 -->		^[165]
S231108u	2023-11-08 12:51:42<	--	2023-11-08 -->			H,L		0.018	0.0	0.0	0.99969	0.0	0.00032	0.0 -->	0.0 -->		^[166]
S231110g	2023-11-10 04:03:20<	--	2023-11-10 -->			H,L		0.670	0.0	0.0	0.968	0.0	0.032	0.0 -->	0.0 -->		^[167]
S231113bb	2023-11-13 12:26:23<	--	2023-11-13 -->			H,L		0.960	0.0	0.0	0.965	0.0041	0.035	0.0 -->	0.0 -->		^[168]
S231113bw	2023-11-13 20:04:17<	--	2023-11-13 -->			H,L		0.543	0.0	0.161	0.743	0.056	0.040	0.000081 -->	0.0 -->		^[169]
S231114n	2023-11-14 04:32:11<	--	2023-11-14 -->			H,L		0.018	0.0	0.0	0.99985	0.0095	0.00015	0.000081 -->	0.0 -->		^[170]
S231118d	2023-11-18 00:56:26<	--	2023-11-18 -->			H,L		0.018	0.0	0.0	0.99981	0.0	0.00019	0.0 -->	0.0 -->		^[171]
S231118ab	2023-11-18 07:14:02<	--	2023-11-18 -->			H,L		0.663	0.0	0.0	0.985	0.0	0.015	0.0 -->	0.0 -->		^[172]
S231118an	2023-11-18 09:06:02<	--	2023-11-18 -->			H,L		0.986	0.0	0.015	0.726	0.017	0.242	0.0 -->	0.0 -->		^[173]
S231119u	2023-11-19 07:52:48<	--	2023-11-19 -->			H,L		0.986	0.0	0.015	0.914	0.041	0.045	0.0 -->	0.0 -->		^[174]
S231123cg	2023-11-23 13:54:30<	--	2023-11-23 -->			H,L		0.018	0.0	0.015	0.99999	0.041	7.6e-6	0.0 -->	0.0 -->		^[175]
S231127cg	2023-11-27 16:53:00<	--	2023-11-27 -->			H,L		0.284	0.0	0.0	0.996	0.0063	0.0044	0.0 -->	0.0 -->		^[176]
S231129ac	2023-11-29 08:17:45<	--	2023-11-29 -->			H,L		0.637	0.0	0.0	0.986	0.0041	0.014	0.0 -->	0.0 -->		^[177]
S231206ca	2023-12-06 23:31:34<	--	2023-12-06 -->			H,L		0.018	0.0	0.0	0.99998	0.0	0.000018	0.0 -->	0.0 -->		^[178]
S231206cc	2023-12-06 23:39:01<	--	2023-12-06 -->			H,L		0.0	0.0	0.0		0.0	0.0	0.0 -->	0.0 -->		^[179]
S231213ap	2023-12-13 11:14:17<	--	2023-12-13 -->			H,L		0.036	0.0	0.0	0.99998	0.0	0.000022	0.0 -->	0.0 -->		^[180]
S231223j	2023-12-23 03:28:36<	--	2023-12-23 -->			H,L		0.062	0.0	0.0	0.99905	0.000023	0.00095	0.0 -->	0.0 -->		^[181]
S231224e	2023-12-24 02:43:21<	--	2023-12-24 -->			H,L		0.084	0.0	0.00019	0.880	0.117	0.0034	0.0000597 -->	0.0 -->		^[182]
S231226av	2023-12-26 10:15:20<	--	2023-12-26 -->			H,L		0.0	0.0	0.0		0.0	0.0	0.0 -->	0.0 -->		^[183]
S231231ag	2023-12-31 15:40:16<	--	2023-12-31 -->			H		4.8 10^−7	0.0	0.0		0.0	2.9e-8	0.0 -->	0.0 -->	Detected by only the Hanford detector, resulting in a bad sky localization.	^[184]
S240104bl	2024-01-04 16:49:32<	--	2024-01-04 -->			H		0.0	0.0	0.0		0.0	2.2e-10	0.0 -->	0.0 -->	Detected by only the Hanford detector, resulting in a bad sky localization.	^[185]
S240107b	2024-01-07 01:32:15<	--	2024-01-07 -->			H,L		0.965	0.0	0.0	0.966	0.0	0.034	0.0 -->	0.0 -->		^[186]
S240109a	2024-01-09 05:04:31<	--	2024-01-09 -->			H		0.344	0.0	0.0	0.995	0.0	0.0053	0.0 -->	0.0 -->	Detected by only the Hanford detector, resulting in a bad sky localization.	^[187]
S240406aj	2024-04-06 06:28:47<	--	2024-04-06 -->			H,L		8.9 10^−8	0.0	0.0		0.0	9.2e-9	0.0 -->	0.0 -->		^[188]
S240413p	2024-04-13 02:20:19<	--	2024-04-13 -->			H,L,V		0.018	0.0	0.0	0.584	0.400	0.020	0.0021 -->	0.0 -->		^[189]
S240420ax	2024-04-20 04:21:16<	--	2024-04-20 -->			H,L		0.961	0.0	0.0	0.0	0.0	<	--	0.0 -->	0.0 -->	Unidentified gravitational wave "burst" lasting 33 milliseconds at a frequency of 219 Hertz.	^[190]
S240422ed	2024-04-22 21:35:13<	--	2024-04-22 -->			H,L,V		1.8 10^-5	0.0	0.541	0.0	0.459	1.3e-5	1.0 -->	1.0 -->		^[191]
S240426s	2024-04-26 03:14:51<	--	2024-04-26 -->			H,L		0.354	0.0	0.0	0.968	0.030	0.00191	0.0 -->	0.0 -->		^[192]
S240428dr	2024-04-28 22:54:40<	--	2024-04-28 -->			H,V		1.2 10^−6	0.0	0.0		0.0	7.4e-8	0.0 -->	0.0 -->		^[193]
S240430ca	2024-04-30 09:35:17<	--	2024-04-30 -->			H,L		0.986	0.0	0.0	0.920	0.041	0.039	0.0 -->	0.0 -->		^[194]
S240501an	2024-05-01 03:35:34<	--	2024-05-01 -->			H,L,V		0.024	0.0	0.0	0.99999	0.0	1.3e-5	0.0 -->	0.0 -->		^[195]
S240505av	2024-05-05 13:35:52<	--	2024-05-05 -->			H,L,V		0.731	0.0	0.0	0.985	0.0	0.015	0.0 -->	0.0 -->		^[196]
S240507p	2024-05-07 04:16:32<	--	2024-05-07 -->			H,L,V		0.036	0.0	0.0	0.963	0.036	0.00031	0.0 -->	0.0 -->		^[197]
S240511i	2024-05-11 03:15:07<	--	2024-05-11 -->			H,L,V		0.018	0.0	0.0	0.99998	0.0	1.7e-5	0.0 -->	0.0 -->		^[198]
S240512r	2024-05-12 02:41:39<	--	2024-05-12 -->			H,L,V		0.018	0.0	0.020	0.958	0.020	0.0017	0.0 -->	0.0 -->		^[199]
S240513ei	2024-05-13 18:33:02<	--	2024-05-13 -->			H,L,V		0.018	0.0	0.0	0.99973	0.0	0.00027	0.0 -->	0.0 -->		^[200]
S240514c	2024-05-14 08:03:21<	--	2024-05-14 -->			L		0.425	0.0	0.0	0.9932	0.0	0.0064	0.0 -->	0.0 -->	Detected by only the Livingston detector, resulting in a bad sky localization.	^[201]
S240514x	2024-05-14 12:17:13<	--	2024-05-14 -->			H,L,V		0.018	0.0	0.0	0.99998	0.0	1.8e-5	0.0 -->	0.0 -->		^[202]
S240515m	2024-05-15 00:53:01<	--	2024-05-15 -->			H,L,V		0.0	0.0	0.0		0.0	4.3e-14	0.0 -->	0.0 -->		^[203]
S240520cv	2024-05-20 21:36:16<	--	2024-05-20 -->			H,L,V		0.018	0.0	0.030	0.921	0.047	0.0018	0.0 -->	0.0 -->		^[204]
S240525p	2024-05-25 03:12:10<	--	2024-05-25 -->			H,L,V		0.619	0.0	0.0	0.902	0.086	0.012	0.0 -->	0.0 -->		^[205]
S240527en	2024-05-27 18:34:29<	--	2024-05-27 -->			H,L,V		0.135	0.0	0.00090	0.99907	0.0	2.7e-5	0.0 -->	0.0 -->		^[206]
S240527fv	2024-05-27 23:09:10<	--	2024-05-27 -->			H,L,V		0.559	0.0	0.0	0.987	0.0036	0.0096	0.0 -->	0.0 -->		^[207]
S240530a	2024-05-30 01:24:17<	--	2024-05-30 -->			H,L,V		0.053	0.0	0.0	0.910	0.085	0.0048	0.0 -->	0.0 -->		^[208]
S240531bp	2024-05-31 07:52:48<	--	2024-05-31 -->			H,L,V		0.00022	0.0	0.0	0.99999	0.0	6.5e-6	0.0 -->	0.0 -->		^[209]
S240601aj	2024-06-01 06:12:00<	--	2024-06-01 -->			H,L		0.829	0.0	0.0	0.507	0.0	0.493	0.0 -->	0.0 -->		^[210]
S240601co	2024-06-01 23:10:04<	--	2024-06-01 -->			H,L,V		0.0034	0.0	0.0	0.928	0.072	0.00023	0.0 -->	0.0 -->		^[211]
S240615dg	2024-06-15 11:36:20<	--	2024-06-15 -->			H,L,V		0.018	0.0	0.0	0.99998	0.0	1.7e-5	0.0 -->	0.0 -->		^[212]
S240615ea	2024-06-15 16:07:35<	--	2024-06-15 -->			H,L,V		0.582	0.0	0.0	0.99938	0.0	0.00062	0.0 -->	0.0 -->		^[213]
S240618ah	2024-06-18 07:16:27<	--	2024-06-18 -->			H,L		0.976	0.0	0.0	0.921	0.041	0.038	0.0 -->	0.0 -->		^[214]
S240621dy	2024-06-21 19:50:59<	--	2024-06-21 -->			H,L,V		0.0	0.0	0.0		0.0	0.0	0.0 -->	0.0 -->		^[215]
S240621eb	2024-06-21 20:09:35<	--	2024-06-21 -->			H,L,V		0.916	0.0	0.0	0.9987	0.0	0.0013	0.0 -->	0.0 -->		^[216]
S240621em	2024-06-21 21:40:41<	--	2024-06-21 -->			H,L,V		0.979	0.0	0.0	0.920	0.041	0.039	0.0 -->	0.0 -->		^[217]
S240622h	2024-06-22 00:40:48<	--	2024-06-22 -->			H,L,V		0.499	0.0	0.0	0.974	0.011	0.015	0.0 -->	0.0 -->		^[218]
S240627by	2024-06-27 13:16:22<	--	2024-06-27 -->			H,L,V		0.500	0.0	0.0	0.911	0.080	0.0084	0.0 -->	0.0 -->		^[219]
S240629by	2024-06-29 14:52:56<	--	2024-06-29 -->			H,L,V		0.018	0.0	0.073	0.798	0.127	0.0015	0.0 -->	0.0 -->		^[220]
S240630t	2024-06-30 10:17:03<	--	2024-06-30 -->			H,L,V		0.00011	0.0	0.0		0.0	3.3e-6	0.0 -->	0.0 -->		^[221]
S240703ad	2024-07-03 19:13:55<	--	2024-07-03 -->			H,V		6.8 10^-6	0.0	0.0		0.0	2.8e-7	0.0 -->	0.0 -->		^[222]
S240705at	2024-07-05 05:32:15<	--	2024-07-05 -->			H,L,V		3.8 10^-8	0.0	0.0		0.0	0.0	0.0 -->	0.0 -->		^[223]
S240716b	2024-07-16 03:49:00<	--	2024-07-16 -->			L,V		4.5 10^-8	0.0	0.0		0.0	3.6e-9	0.0 -->	0.0 -->		^[224]
S240807h	2024-08-07 21:45:59<	--	2024-08-07 -->			L,V		0.0012	0.0	0.00010	0.956	0.044	3.2e-5	0.0 -->	0.0 -->		^[225]
S240813c	2024-08-13 03:45:48<	--	2024-08-13 -->			L,V		0.139	0.0	0.0	0.909	0.089	0.0022	0.0 -->	0.0 -->		^[226]
S240813d	2024-08-13 04:39:13<	--	2024-08-13 -->			L,V		0.0	0.0	0.0		0.0	1.2e-11	0.0 -->	0.0 -->		^[227]

See also

• GRB 150101B, a weak gamma-ray burst trigger observed prior to aLIGO O1 (beginning September 12, 2015), with claimed similarities to model-supported possible neutron star merger GW170817/GRB 170817A/AT2017gfo.

External links

• Web site: Detections . LIGO .

Notes and References

1. Web site: GW150914 - The First Direct Detection of Gravitational Waves . 2023-03-15 . www.ligo.org.
2. Web site: LSC News . 2023-03-15 . www.ligo.org.
3. The LIGO Scientific Collaboration . the Virgo Collaboration . Abbott . B. P. . Abbott . R. . Abbott . T. D. . Abraham . S. . Acernese . F. . Ackley . K. . Adams . C. . Adhikari . R. X. . Adya . V. B. . 2019-09-04 . GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo during the First and Second Observing Runs . Physical Review X . 9 . 3 . 031040 . 1811.12907 . 2019PhRvX...9c1040A . 10.1103/PhysRevX.9.031040 . 2160-3308 . 119366083.
4. Web site: Burtnyk . Kimberly . 2019-10-01 . LIGO's Commissioning Break Commences . 2020-07-01 . LIGO Lab Caltech.
5. https://observing.docs.ligo.org/plan/ Ligo, Virgo and Kagra Observing Run Plans
6. Web site: IGWN | Observing Plans .
7. Web site: GCN/LVC Notices. Goddard Space Flight Center. 2019-11-11.
8. Fragione, Giacomo . et al. . Black Hole and Neutron Star Mergers in Galactic Nuclei . Monthly Notices of the Royal Astronomical Society . 488 . 1 . 47–63 . 1811.10627 . 10.1093/mnras/stz1651 . 2019MNRAS.488...47F . 2019 . free . 85459844 .
9. News: Strickland . Ashley . Scientists may have detected violent collision between neutron star, black hole . 3 May 2019 . . 3 May 2019 .
10. The relatively large and distant area of the sky within which it is claimed to be possible to localize the source.
11. 1 Mpc is approximately 3.26 Mly.
12. c²M_☉ is about 1.787E+47J, or 1.787E+47J.
13. The chirp mass is the binary parameter most relevant to the evolution of the inspiral gravitational waveform, and thus is the mass that can be measured most accurately. It is related to, but less than, the geometric mean (m _{geo} ) of the binary masses, according to m _{geo} \left( (m _{geo})/(m _{1} + m _{2}) \right) ^{1/5} , thus ranging from ~87% of m _{geo} when the masses are the same to ~78% when they differ by an order of magnitude.
14. 10.1103/PhysRevLett.116.061102 . 26918975 . Observation of Gravitational Waves from a Binary Black Hole Merger . 11 February 2016 . B.P. . Abbott . etal. . . 116 . 6 . 061102. 2016PhRvL.116f1102A . 1602.03837. 124959784 .
15. News: LIGO detects first ever gravitational waves – from two merging black holes . 11 February 2016 . Tushna Commissariat . Physics World .
16. An improved analysis of GW150914 using a fully spin-precessing waveform model . Physical Review X . 6 . 4 . 041014 . The LIGO Scientific Collaboration and The Virgo Collaboration . 3 June 2016. 10.1103/PhysRevX.6.041014. 1606.01210. 2016PhRvX...6d1014A. 18217435 .
17. 10.1103/PhysRevX.6.041015 . Binary Black Hole Mergers in the first Advanced LIGO Observing Run . . 21 October 2016 . B.P. . Abbott . . 6 . 4 . 041015 . 1606.04856. 2016PhRvX...6d1015A . 31926886 .
18. 10.3847/1538-4357/ab0108. 1-OGC: The first open gravitational-wave catalog of binary mergers from analysis of public Advanced LIGO data. 25 February 2019. 1811.01921. Astrophysical Journal. 872. 2. 195. Alexander H.. Nitz. 2019ApJ...872..195N. 119389481 . free .
19. 10.1103/PhysRevLett.116.241103 . 27367379 . GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence . . 15 June 2016 . B.P. . Abbott . . 116 . 24 . 241103. 2016PhRvL.116x1103A . 1606.04855. 118651851 .
20. GW151226: A Second Confirmed Source of Gravitational Radiation . 15 June 2016 .
21. 10.1103/PhysRevLett.118.221101 . 28621973 . GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2 . . 1 June 2017 . B.P. . Abbott . . 118 . 22 . 221101. 1706.01812 . 2017PhRvL.118v1101A . 206291714 .
22. News: Overbye . Dennis . Dennis Overbye . Gravitational Waves Felt From Black-Hole Merger 3 Billion Light-Years Away . 1 June 2017 . . 1 June 2017 .
23. LIGO Scientific Collaboration and Virgo Collaboration . Abbott . B.P. . GW170608: Observation of a 19-solar-mass Binary Black Hole Coalescence. 10.3847/2041-8213/aa9f0c. 1711.05578. The Astrophysical Journal Letters. 851. 2. L35 . 18 December 2017. 2017ApJ...851L..35A. 9030576 . free .
24. 2019. 1811.12907. LIGO Scientific Collaboration and Virgo Collaboration . Abbott . B.P. . GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo during the First and Second Observing Runs. Physical Review X. 9. 3. 031040. etal. 10.1103/PhysRevX.9.031040. 2019PhRvX...9c1040A. 119366083.
25. LIGO Scientific Collaboration and Virgo Collaboration . Abbott . B.P. . GW170814: A three-detector observation of gravitational waves from a binary black hole coalescence . . 119 . 14 . 141101 . 10.1103/PhysRevLett.119.141101 . 1709.09660 . 2017-10-06 . 2017PhRvL.119n1101A . 29053306. 46829350 .
    • Gravitational waves from a binary black hole merger observed by LIGO and Virgo . LIGO Scientific Collaboration .
26. News: Overbye . Dennis . Dennis Overbye . New Gravitational Wave Detection From Colliding Black Holes . 27 September 2017 . . 28 September 2017 .
27. Abbott . B.P. . LIGO Scientific Collaboration & Virgo Collaboration. GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral. Physical Review Letters. 16 October 2017. 119. 16. 161101 . 10.1103/PhysRevLett.119.161101. 29099225 . 1710.05832. 2017PhRvL.119p1101A. 217163611 .
28. Abbott . B.P. . etal. . LIGO, Virgo and other collaborations . Multi-messenger Observations of a Binary Neutron Star Merger . . October 2017 . 848 . 2 . L12 . 10.3847/2041-8213/aa91c9 . free . 1710.05833 . 2017ApJ...848L..12A.
29. News: Cho . Adrian . Merging neutron stars generate gravitational waves and a celestial light show . 16 October 2017 . . 16 October 2017 .
30. The LIGO Scientific Collaboration . the Virgo Collaboration . GWTC-2.1: Deep Extended Catalog of Compact Binary Coalescences Observed by LIGO and Virgo During the First Half of the Third Observing Run . 5 January 2024 . 2108.01045 . Physical Review D . 109 . 2 . 022001 . 10.1103/PhysRevD.109.022001 . 2024PhRvD.109b2001A .
31. GWTC-2: Compact Binary Coalescences Observed by LIGO and Virgo during the First Half of the Third Observing Run . 2010.14527 . The LIGO Scientific Collaboration . the Virgo Collaboration . Physical Review X . 2021 . 11 . 2 . 021053 . 10.1103/PhysRevX.11.021053 . 2021PhRvX..11b1053A . 225094244 .
32. Web site: Superevent info - S190412m . LIGO . 12 April 2019.
33. GW190412: Observation of a Binary-Black-Hole Coalescence with Asymmetric Masses . 17 April 2020 . 2004.08342 . The LIGO Scientific Collaboration . the Virgo Collaboration . Abbott . R. . Abbott . T. D. . Abraham . S. . Acernese . F. . Ackley . K. . Adams . C. . Adhikari . R. X. . Adya . V. B. . Affeldt . C. . Agathos . M. . Agatsuma . K. . Aggarwal . N. . Aguiar . O. D. . Aich . A. . Aiello . L. . Ain . A. . Ajith . P. . Akcay . S. . Allen . G. . Allocca . A. . Altin . P. A. . Amato . A. . Anand . S. . Ananyeva . A. . Anderson . S. B. . Anderson . W. G. . Angelova . S. V. . Ansoldi . S. . Physical Review D . 102 . 4 . 043015 . 10.1103/PhysRevD.102.043015 . 2020PhRvD.102d3015A . 215814461 . 3 .
34. News: Gravitational waves reveal a second neutron star collision. 8 January 2020.
35. 10.1134/S032001081911007X . 1912.13112. Наблюдение в гамма-диапазоне второго связанного со слиянием нейтронных звезд события LIGO/Virgo S190425z. 2019. Позаненко. А. С.. Минаев. П. Ю.. Гребенев. С. А.. Человеков. И. В.. Письма В Астрономический Журнал: Астрономия И Космическая Астрофизика. 45. 11. 768–786 . 239427905. ru.
36. Web site: Superevent info - S190425z . LIGO . 25 April 2019.
37. GW190425: Observation of a Compact Binary Coalescence with Total Mass ~ 3.4 M_☉. 6 January 2020 . 2001.01761 . The LIGO Scientific Collaboration . the Virgo Collaboration . Abbott . R. . The Astrophysical Journal . 892 . 1 . L3 . 10.3847/2041-8213/ab75f5 . 2020ApJ...892L...3A . 210023687 . 2 . free .
38. Abbott . R. . etal. . GW190521: A Binary Black Hole Merger with a Total Mass of 150 M ⊙ . Physical Review Letters . 2 September 2020 . 125 . 10 . 101102 . 10.1103/PhysRevLett.125.101102 . 32955328 . 2009.01075 . 2020PhRvL.125j1102A . 221447506 . en. free .
39. Abbott . R. . etal. . Properties and Astrophysical Implications of the 150 M ⊙ Binary Black Hole Merger GW190521 . The Astrophysical Journal . 2 September 2020 . 900 . 1 . L13 . 10.3847/2041-8213/aba493. 2009.01190 . 2020ApJ...900L..13A . 221447444 . 11343/273616 . free . free .
40. News: Black hole or neutron star?. June 23, 2020.
41. Web site: Superevent info - S190814bv. LIGO . 15 August 2019.
42. News: Starr . Michelle. Early Reports Indicate We May Have Detected a Black Hole And Neutron Star Collision . 16 August 2019 . ScienceAlert.com . 16 August 2019 .
43. News: Mandelbum . Ryan F. . Mystery Deepens Around Newly Detected Ripples in Space-Time . 26 August 2019 . . 26 August 2019 .
44. News: Starr . Michelle . First Papers on The Black Hole-Neutron Star Merger Are In. Here's What We Didn't See . 11 February 2020 . ScienceAlert.com . 11 February 2020.
45. Ackley, K. . et al. . Observational constraints on the optical and near-infrared emission from the neutron star-black hole binary merger S190814bv . 5 February 2020 . 2002.01950v1 . astro-ph.SR .
46. News: Overbye . Dennis . Dennis Overbye . A Black Hole's Lunch Provides a Treat for Astronomers - Scientists have discovered the heaviest known neutron star, or maybe the lightest known black hole: "Either way it breaks a record." . 24 June 2020 . . 24 June 2020 .
47. News: Starr . Michelle . Astronomers Detect First-Ever Mystery Object in The 'Mass Gap' of Cosmic Collisions . 24 June 2020 . ScienceAlert.com . 24 June 2020 .
48. News: . Gravitational wave scientists grapple with the cosmic mystery of GW190814 . 23 June 2020 . . 24 June 2020 .
49. Abbott, R. . et al. . GW190814: Gravitational Waves from the Coalescence of a 23 Solar Mass Black Hole with a 2.6 Solar Mass Compact Object . 23 June 2020 . . 896 . 2 . L44 . 10.3847/2041-8213/ab960f . 2006.12611 . 2020ApJ...896L..44A . free .
50. GWTC-3: Compact Binary Coalescences Observed by LIGO and Virgo during the Second Part of the Third Observing Run . 2023 . 2111.03606 . The LIGO Scientific Collaboration . the Virgo Collaboration . the KAGRA Collaboration . Abbott . R. . Abbott . T. D. . Acernese . F. . Ackley . K. . Adams . C. . Adhikari . N. . Adhikari . R. X. . Adya . V. B. . Affeldt . C. . Agarwal . D. . Agathos . M. . Agatsuma . K. . Aggarwal . N. . Aguiar . O. D. . Aiello . L. . Ain . A. . Ajith . P. . Akcay . S. . Akutsu . T. . Albanesi . S. . Allocca . A. . Altin . P. A. . Amato . A. . Anand . C. . Anand . S. . Ananyeva . A. . Anderson . S. B. . Physical Review X . 13 . 4 . 041039 . 10.1103/PhysRevX.13.041039 . 2023PhRvX..13d1039A . 1 .
51. 10.3847/2041-8213/ac082e. Observation of Gravitational Waves from Two Neutron Star–Black Hole Coalescences. 2021. Abbott. R.. Abbott. T. D.. Abraham. S.. Acernese. F.. Ackley. K.. Adams. A.. Adams. C.. Adhikari. R. X.. Adya. V. B.. Affeldt. C.. Agarwal. D.. Agathos. M.. Agatsuma. K.. Aggarwal. N.. Aguiar. O. D.. Aiello. L.. Ain. A.. Ajith. P.. Akutsu. T.. Aleman. K. M.. Allen. G.. Allocca. A.. Altin. P. A.. Amato. A.. Anand. S.. Ananyeva. A.. Anderson. S. B.. Anderson. W. G.. Ando. M.. Angelova. S. V.. The Astrophysical Journal Letters. 915. 1. L5. 2106.15163. 2021ApJ...915L...5A. 235670241. 1 . free .
52. Web site: Superevent info - S200105ae. LIGO . 6 January 2020.
53. Bustillo . Juan Calderon . Sanchis-Gual . Nicolas . Leong . Samson H. W. . Chandra . Koustav . Torres-Forne . Alejandro . Font . Jose A. . Herdeiro . Carlos . Radu . Eugen . Wong . Isaac C. F. . Li . T. G. F. . Searching for vector boson-star mergers within LIGO-Virgo intermediate-mass black-hole merger candidates . Physical Review D . 2023 . 108 . 12 . 123020 . 10.1103/PhysRevD.108.123020 . 2206.02551 . 2023PhRvD.108l3020C .
54. Hourihane . Sophie . Chatziioannou . Katerina . Wijngaarden . Marcella . Davis . Derek . Littenberg . Tyson . Cornish . Neil . Accurate modeling and mitigation of overlapping signals and glitches in gravitational-wave data . Physical Review D . 15 August 2022 . 106 . 4 . 042006 . 10.1103/PhysRevD.106.042006 . 2205.13580 . 2022PhRvD.106d2006H . 249152318 .
55. Web site: Superevent info - S200115j. LIGO . 15 January 2020.
56. LIGO Scientific Collaboration . Virgo Collaboration . KAGRA Collaboration . 5 April 2024 . Observation of Gravitational Waves from the Coalescence of a 2.5-4.5 Msun Compact Object and a Neutron Star . Preprint.
57. News: Hartono . Naomi . 15 Years of Radio Data Reveals Evidence of Space-Time Murmur . 3 July 2023 . NASA . 29 June 2023.
58. 1 Mpc is approximately 3.26 Mly.
59. Which instruments observed the event. (H = LIGO Hanford, L=LIGO Livingston, V=Virgo)
60. Nitz . Alexander H. . Dent . Thomas . Davies . Gareth S. . Kumar . Sumit . Capano . Collin D. . Harry . Ian . Mozzon . Simone . Nuttall . Laura . Lundgren . Andrew . Tápai . Márton . 2-OGC: Open Gravitational-wave Catalog of Binary Mergers from Analysis of Public Advanced LIGO and Virgo Data . The Astrophysical Journal . 12 March 2020 . 891 . 2 . 123 . 10.3847/1538-4357/ab733f . 1910.05331 . 2020ApJ...891..123N . 204403263 . free .
61. Venumadhav . Tejaswi . Zackay . Barak . Roulet . Javier . Dai . Liang . Zaldarriaga . Matias . New Binary Black Hole Mergers in the Second Observing Run of Advanced LIGO and Advanced Virgo . Physical Review D . 2020 . 101 . 8 . 083030 . 10.1103/PhysRevD.101.083030 . 1904.07214 . 2020PhRvD.101h3030V . 119188594 .
62. Zackay . Barak . Dai . Liang . Venumadhav . Tejaswi . Roulet . Javier . Zaldarriaga . Matias . Detecting Gravitational Waves With Disparate Detector Responses: Two New Binary Black Hole Mergers . Phys. Rev. D . 2021 . 104 . 8 . 063030 . 10.1103/PhysRevD.101.083030 . 1910.09528 . 2020PhRvD.101h3030V . 119188594 . en.
63. Web site: Real-time alerts and circulars tracker . nasa.gov.
64. Web site: Observing Plans and Public Alerts . October 2018 . www.ligo.org . LIGO Scientific Collaboration . 2018-10-28.
65. Web site: What constitutes an open, public alert? . Singer . Leo P. . 16 March 2017 . LSC (LIGO Scientific Collaboration) . 30 October 2018 . gw-astronomy.org.
66. Web site: GraceDB — Gravitational Wave Candidate Event Database . ligo.org.
67. Web site: Real-time alerts and circulars tracker . nasa.gov.
68. Web site: LIGO Announces Commissioning Break . LIGO Lab Caltech . 7 November 2019.
69. Web site: KAGRA Gravitational-wave Telescope Starts Observation « KAGRA Large-scale Cryogenic Graviationai wave Telescope Project. ja. 2020-02-27.
70. Web site: KAGRA to Join LIGO and Virgo in Hunt for Gravitational Waves. LIGO Lab Caltech. 2019-10-06.
71. Web site: LIGO Suspends Third Observing Run (O3) . LIGO Lab . Caltech . 20 April 2020.
72. Web site: LIGO Laboratory's Response to COVID-19 . LIGO Lab . Caltech . 24 March 2020.
73. The area of the sky within which it was possible to localize the source.
74. 1 Mpc is approximately 3.26 Mly.
75. Which instruments observed the event. (H = LIGO Hanford, L=LIGO Livingston, V=Virgo)
76. The chance a random signal of this significance would occur at any point in O3's 11-month run. Calculated by 1 - (1-false alarm rate in Hz)^28,512,000. This is not the chance of the given signal being 'real' or not: Background contamination (such as earthquakes) can cause statistically significant signals as well, and although four detections have a >50% chance to have occurred randomly in O3, there is only a 19.4% chance that none of these signals would be real.
77. Probability that both components have mass < 3 M_☉
78. Probability that one component has mass < 3 M_☉ and the other has mass > 5 M_☉
79. Probability that both components have mass > 5 M_☉
80. Probability that at least one component has a mass in the range 3-5 M_☉, between those of known neutron stars and black holes, a range sometimes identified as the "lower" mass gap
81. Probability that the source is terrestrial or non-cosmological (e.g. foreground noises and signals [e.g. "noise"] or a technical/systematic error ["glitch"])
82. Web site: Superevent info - S190901ap . LIGO . 6 September 2019.
83. Web site: Superevent info - S190910d . LIGO . 10 September 2019.
84. Web site: Superevent info - S190910h . LIGO . 10 September 2019.
85. Web site: Superevent info - S190923y. LIGO . 24 September 2019.
86. Web site: Superevent info - S190930t. LIGO . 30 September 2019.
87. Web site: Superevent info - S191205ah. LIGO . 5 December 2019.
88. Web site: Superevent info - S191213g. LIGO . 14 December 2019.
89. Web site: Superevent info - S200213t. LIGO . 13 February 2020.
90. Web site: LIGO, Virgo and Kagra Observing Run Plans . LIGO Lab . Caltech . 16 July 2022.
91. News: Burtnyk . Kimberly . Latest Update on Start of Next Observing Run (O4) . 18 May 2023 . LIGO . Caltech.
92. Web site: Detector status - 29 April 2023 . gwosc.org . 18 May 2023.
93. Web site: Detector status - 5 May 2023 . gwosc.org.
94. The area of the sky within which it was possible to localize the source.
95. 1 Mpc is approximately 3.26 Mly.
96. Which instruments observed the event. (H = LIGO Hanford, L=LIGO Livingston, V=Virgo)
97. The chance a random signal of this significance would occur at any point in O4's 20-month run. Calculated by 1 - (1-false alarm rate in Hz)^57,456,000. This is not the chance of the given signal being 'real' or not: Even if there is a 90% chance of O4 having random noise eventually reach a certain level of significance, the chance of such noise occurring 100 separate times in the same period is still very low (in this example, around 0.0026%).
98. The following events had a pAstro of over 50%, but were at a low significance and thus not validated by the LIGO-Virgo collaboration. Many of these events are likely real, but at least some are likely false positives:
    2023 May: S230524b (BBH, pAstro = 0.725), S230525a (BBH, pAstro = 0.724), S230527bv (BBH, pAstro = 0.882), S230528a (NSMG, pAstro = 0.643), S230528bt (BBH, pAstro = 0.880)
    June: S230604z (BBH, pAstro = 0.748), S230606z (BBH, pAstro = 0.835), S230609a (BBH, pAstro = 0.956), S230615av (BBH, pAstro = 0.912), S230615az (BNS, pAstro = 0.847), S230623at (BBH, pastro = 0.707), S230628aj (BBH, pAstro = 0.694)
    July: S230704bd (BBH, pAstro = 0.755), S230711b (BBH, pAstro = 0.792), S230716o (BBH, pAstro = 0.750), S230725am (BBH, pAstro = 0.502), S230728ap (BBH, pAstro = 0.940)
    August: S230822ac (BBH, pAstro = 0.813), S230830q (BBH, pAstro = 0.923)
    September: S230902af (BBH, pAstro = 0.798), S230904bg (BBH, pAstro = 0.688)
    October: S231004bq (BBH, pAstro = 0.708), S231007w (BBH, pAstro = 0.746), S231025a (BNS, pAstro = 0.588), S231025ap (BBH, pAstro = 0.830)
    November: S231124z (BBH, pAstro = 0.647)
    December: S231223bg (BBH, pAstro = 0.690)
    2024 January: S240116p (BBH, pAstro = 0.789)
    April: S240407v (BBH, pAstro = 0.882), S240420dc (BBH, pAstro = 0.887), S240427am (BBH, pAstro = 0.639)
    May: S240513cx (BBH, pAstro = 0.738), S240525dy (BBH, pAstro = 0.885), S240526ak (BBH, pAstro = 0.626), S240527dh (BBH, pAstro = 0.915), S240531aa (BBH, pAstro = 0.905)
    June: S240613z (BBH, pAstro = 0.923), S240619z (BBH, pAstro = 0.739), S240621ch (BBH, pAstro = 0.680), S240627co (BBH, pAstro = 0.713)
    July: S240701bn (BBH, pAstro = 0.824)
99. Probability that both components have mass < 3 M_☉
100. Probability that one component has mass < 3 M_☉ and the other has mass > 5 M_☉
101. Probability that both components have mass > 5 M_☉
102. Probability that at least one component has a mass in the range 3-5 M_☉, between those of known neutron stars and black holes, a range sometimes identified as the "lower" mass gap
103. Probability that the source is terrestrial or non-cosmological (e.g. foreground noises and signals [e.g. "noise"] or a technical/systematic error ["glitch"])
104. Web site: Superevent info - S230518h . LIGO . 18 May 2023.
105. Web site: Superevent info - S230520ae . LIGO . 21 May 2023.
106. Web site: Superevent info - S230522a . LIGO . 22 May 2023.
107. Web site: Superevent info - S230522n . LIGO . 22 May 2023.
108. Web site: Superevent info - S230601bf . LIGO . 1 June 2023.
109. Web site: Superevent info - S230605o . LIGO . 5 June 2023.
110. Web site: Superevent info - S230606d . LIGO . 6 June 2023.
111. Web site: Superevent info - S230608as . LIGO . 8 June 2023.
112. Web site: Superevent info - S230609u . LIGO . 9 June 2023.
113. Web site: Superevent info - S230624av . LIGO . 24 June 2023.
114. Web site: Superevent info - S230627c . LIGO . 27 June 2023.
115. Web site: Superevent info - S230628ax . LIGO . 28 June 2023.
116. Web site: Superevent info - S230630am . LIGO . 30 June 2023.
117. Web site: Superevent info - S230630bq . LIGO . 30 June 2023.
118. Web site: Superevent info - S230702an . LIGO . 2 July 2023.
119. Web site: Superevent info - S230704f . LIGO . 4 July 2023.
120. Web site: Superevent info - S230706ah . LIGO . 6 July 2023.
121. Web site: Superevent info - S230707ai . LIGO . 7 July 2023.
122. Web site: Superevent info - S230708t . LIGO . 8 July 2023.
123. Web site: Superevent info - S230708z . LIGO . 8 July 2023.
124. Web site: Superevent info - S230708cf . LIGO . 8 July 2023.
125. Web site: Superevent info - S230709bi . LIGO . 9 July 2023.
126. Web site: Superevent info - S230723ac . LIGO . 23 July 2023.
127. Web site: Superevent info - S230726a . LIGO . 26 July 2023.
128. Web site: Superevent info - S230729z . LIGO . 29 July 2023.
129. Web site: Superevent info - S230731an . LIGO . 31 July 2023.
130. Web site: Superevent info - S230802aq . LIGO . 2 August 2023.
131. Web site: Superevent info - S230805x . LIGO . 5 August 2023.
132. Web site: Superevent info - S230806ak . LIGO . 6 August 2023.
133. Web site: Superevent info - S230807f . LIGO . 7 August 2023.
134. Web site: Superevent info - S230811n . LIGO . 11 August 2023.
135. Web site: Superevent info - S230814r . LIGO . 14 August 2023.
136. Web site: Superevent info - S230814ah . LIGO . 14 August 2023.
137. Web site: Superevent info - S230819ax . LIGO . 19 August 2023.
138. Web site: Superevent info - S230820bq . LIGO . 20 August 2023.
139. Web site: Superevent info - S230822bm . LIGO . 22 August 2023.
140. Web site: Superevent info - S230824r . LIGO . 24 August 2023.
141. Web site: Superevent info - S230825k . LIGO . 25 August 2023.
142. Web site: Superevent info - S230831e . LIGO . 31 August 2023.
143. Web site: Superevent info - S230904n . LIGO . 4 September 2023.
144. Web site: Superevent info - S230911ae . LIGO . 11 September 2023.
145. Web site: Superevent info - S230914ak . LIGO . 14 September 2023.
146. Web site: Superevent info - S230919bj . LIGO . 19 September 2023.
147. Web site: Superevent info - S230920al . LIGO . 20 September 2023.
148. Web site: Superevent info - S230922g . LIGO . 22 September 2023.
149. Web site: Superevent info - S230922q . LIGO . 22 September 2023.
150. Web site: Superevent info - S230924an . LIGO . 24 September 2023.
151. Web site: Superevent info - S230927l . LIGO . 27 September 2023.
152. Web site: Superevent info - S230927be . LIGO . 27 September 2023.
153. Web site: Superevent info - S230928cb . LIGO . 28 September 2023.
154. Web site: Superevent info - S230930al . LIGO . 30 September 2023.
155. Web site: Superevent info - S231001aq . LIGO . 1 October 2023.
156. Web site: Superevent info - S231005j . LIGO . 5 October 2023.
157. Web site: Superevent info - S231005ah . LIGO . 5 October 2023.
158. Web site: Superevent info - S231008ap . LIGO . 8 October 2023.
159. Web site: Superevent info - S231014r . LIGO . 14 October 2023.
160. Web site: Superevent info - S231020ba . LIGO . 20 October 2023.
161. Web site: Superevent info - S231020bw . LIGO . 20 October 2023.
162. Web site: Superevent info - S231028bg . LIGO . 28 October 2023.
163. Web site: Superevent info - S231029y . LIGO . 29 October 2023.
164. Web site: Superevent info - S231102w . LIGO . 2 November 2023.
165. Web site: Superevent info - S231104ac . LIGO . 4 November 2023.
166. Web site: Superevent info - S231108u . LIGO . 8 November 2023.
167. Web site: Superevent info - S231110g . LIGO . 10 November 2023.
168. Web site: Superevent info - S231113bb . LIGO . 13 November 2023.
169. Web site: Superevent info - S231113bw . LIGO . 13 November 2023.
170. Web site: Superevent info - S231114n . LIGO . 14 November 2023.
171. Web site: Superevent info - S231118d . LIGO . 18 November 2023.
172. Web site: Superevent info - S231118ab . LIGO . 18 November 2023.
173. Web site: Superevent info - S231118an . LIGO . 18 November 2023.
174. Web site: Superevent info - S231119u . LIGO . 19 November 2023.
175. Web site: Superevent info - S231123cg . LIGO . 23 November 2023.
176. Web site: Superevent info - S231127cg . LIGO . 27 November 2023.
177. Web site: Superevent info - S231129ac . LIGO . 29 November 2023.
178. Web site: Superevent info - S231206ca . LIGO . 7 December 2023.
179. Web site: Superevent info - S231206cc . LIGO . 7 December 2023.
180. Web site: Superevent info - S231213ap . LIGO . 13 December 2023.
181. Web site: Superevent info - S231223j . LIGO . 23 December 2023.
182. Web site: Superevent info - S231224e . LIGO . 24 December 2023.
183. Web site: Superevent info - S231226av . LIGO . 26 December 2023.
184. Web site: Superevent info - S231231ag . LIGO . 31 December 2023.
185. Web site: Superevent info - S240104bl . LIGO . 4 January 2024.
186. Web site: Superevent info - S240107b . LIGO . 7 January 2024.
187. Web site: Superevent info - S240109a . LIGO . 9 January 2024.
188. Web site: Superevent info - S240406aj . LIGO . 6 April 2024.
189. Web site: Superevent info - S240413p . LIGO . 13 April 2024.
190. Web site: Superevent info - S240420ax . LIGO . 20 April 2024.
191. Web site: Superevent info - S240422ed . LIGO . 22 April 2024.
192. Web site: Superevent info - S240426s . LIGO . 26 April 2024.
193. Web site: Superevent info - S240428dr . LIGO . 28 April 2024.
194. Web site: Superevent info - S240430ca . LIGO . 30 April 2024.
195. Web site: Superevent info - S240501an . LIGO . 1 May 2024.
196. Web site: Superevent info - S240505av . LIGO . 5 May 2024.
197. Web site: Superevent info - S240507p . LIGO . 7 May 2024.
198. Web site: Superevent info - S240511i . LIGO . 11 May 2024.
199. Web site: Superevent info - S240512r . LIGO . 12 May 2024.
200. Web site: Superevent info - S240513ei . LIGO . 13 May 2024.
201. Web site: Superevent info - S240514c . LIGO . 14 May 2024.
202. Web site: Superevent info - S240514x . LIGO . 14 May 2024.
203. Web site: Superevent info - S240515m . LIGO . 15 May 2024.
204. Web site: Superevent info - S240520cv . LIGO . 20 May 2024.
205. Web site: Superevent info - S240525p . LIGO . 25 May 2024.
206. Web site: Superevent info - S240527en . LIGO . 28 May 2024.
207. Web site: Superevent info - S240527fv . LIGO . 27 May 2024.
208. Web site: Superevent info - S240530a . LIGO . 30 May 2024.
209. Web site: Superevent info - S240531bp . LIGO . 31 May 2024.
210. Web site: Superevent info - S240601aj . LIGO . 1 June 2024.
211. Web site: Superevent info - S240601co . LIGO . 1 June 2024.
212. Web site: Superevent info - S240615dg . LIGO . 15 June 2024.
213. Web site: Superevent info - S240615ea . LIGO . 16 June 2024.
214. Web site: Superevent info - S240618ah . LIGO . 18 June 2024.
215. Web site: Superevent info - S240621dy . LIGO . 22 June 2024.
216. Web site: Superevent info - S240621eb . LIGO . 22 June 2024.
217. Web site: Superevent info - S240621em . LIGO . 22 June 2024.
218. Web site: Superevent info - S240622h . LIGO . 22 June 2024.
219. Web site: Superevent info - S240627by . LIGO . 27 June 2024.
220. Web site: Superevent info - S240629by . LIGO . 29 June 2024.
221. Web site: Superevent info - S240630t . LIGO . 30 June 2024.
222. Web site: Superevent info - S240703ad . LIGO . 3 July 2024.
223. Web site: Superevent info - S240705at . LIGO . 5 July 2024.
224. Web site: Superevent info - S240716b . LIGO . 16 July 2024.
225. Web site: Superevent info - S240807h . LIGO . 7 August 2024.
226. Web site: Superevent info - S240813c . LIGO . 13 August 2024.
227. Web site: Superevent info - S240813d . LIGO . 13 August 2024.