List Of Gravitational Wave Observations

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

Origin and nomenclature

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

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. 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 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, initially planned to end after one year, has been extended to run until 7 October 2025, following plans to make further upgrades for the O5 run. Updated observing plans are published on the official website, containing the latest information on these runs.Ligo, Virgo and Kagra Observing Run Plans
/ref> There was a two month commissioning break from January to March 2024, and another from 1 April to a planned 4 June 2025, after which observations will resume for the remainder of O4. As of May 2025, O5 is planned to begin in late 2027.

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. 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). Some objects are in the mass gap (MG) between the largest predicted neutron star masses (Tolman–Oppenheimer–Volkoff limit) and the smallest known black holes.

List of gravitational wave events

O1&O2.svg , O1 & O2/2015-2017 events
Gravitational wave detection graph.png , Distance and mass for events up to O4 in 2023

}
! colspan=2, Primary
! colspan=2, Secondary
! colspan=3, Remnant
! rowspan=2 style="min-width:15em", Notes
! rowspan=2 class=unsortable, Ref.
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!, Type
!, Mass (M_☉)
!, Type
!, Mass (M_☉)
!, Type
!, Mass (M_☉)
!, Spin
, -
, BGCOLOR="#fff0f0", GW150914
09:50:45
, , 2016-02-11
, ,
, ,
, ,
, ,
, ,
, ,
, style="background:#888888; text-align:center;", BH

, ,
, style="background:#888888; text-align:center;", BH

, ,
, bgcolor="888888",
, ,
, ,
, , First GW detection;
first BH merger observed
, ,
, -
, BGCOLOR="#fff0f0",
09:54:43
, , 2016-06-15
, ,
, ,
, ,
, ,
, ,
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, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Formerly candidate LVT151012;
accepted as astrophysical since February 2019
, ,
, -
, BGCOLOR="#fff0f0", GW151226
03:38:53
, , 2016-06-15
, ,
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, bgcolor="888888",
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, -
, BGCOLOR="#fffff0", GW170104
10:11:58
, , 2017-06-01
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, bgcolor="888888",
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, BGCOLOR="#fffff0", GW170608
02:01:16
, , 2017-11-16
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, bgcolor="888888",
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, bgcolor="888888",
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, bgcolor="888888",
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, ,
, , Smallest BH progenitor
masses to date
, ,
, -
, BGCOLOR="#fffff0", GW170729
18:56:29
, , 2018-11-30
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, ,
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, bgcolor="888888",
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, bgcolor="888888",
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, , Largest progenitor masses until GW190521
, ,
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, BGCOLOR="#fffff0", GW170809
08:28:21
, , 2018-11-30
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, bgcolor="888888",
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, BGCOLOR="#fffff0", GW170814
10:30:43
, , 2017-09-27
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, bgcolor="888888",
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, , First announced detection by
three observatories; first polarization measurement
, ,
*
, -
, BGCOLOR="#fffff0", GW170817
12:41:04
, , 2017-10-16
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, bgcolor=AADDDD,
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, bgcolor=AADDDD,
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, style="background:#AADDDD; text-align:center;", HMNS-BH

, style="text-align:center;", ≤ 2.8
, ,
, , First NS merger observed in
GW; first detection of EM counterpart ( GRB 170817A; AT 2017gfo); nearest event to date
, ,
, -
, BGCOLOR="#fffff0", GW170818
02:25:09
, , 2018-11-30
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, bgcolor="888888",
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, BGCOLOR="#fffff0", GW170823
13:13:58
, , 2018-11-30
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, bgcolor="888888",
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, BGCOLOR="#f0fff0", GW190403_051519
2019-04-03 05:15:19
, , 2022-05-11
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, bgcolor="888888",
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, -
, BGCOLOR="#f0fff0", GW190408_181802
2019-04-08 18:18:02
, , 2020-10-27
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, bgcolor="888888",
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, ,
, , Originally designated S190408an.
, ,

, -
, BGCOLOR="#f0fff0", GW190412
2019-04-12
05:30:44
, , 2020-04-17
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, bgcolor="888888",
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, , First possible observation of a merger of two black holes of very different masses. Originally designated S190412m.
, ,

, -
, BGCOLOR="#f0fff0", GW190413_052954
2019-04-13
, , 2020-10-27
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, bgcolor="888888",
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, -
, BGCOLOR="#f0fff0", GW190413_134308
2019-04-13
, , 2020-10-27
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, bgcolor="888888",
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, bgcolor="888888",
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, -
, BGCOLOR="#f0fff0", GW190421_213856
2019-04-21
, , 2020-10-27
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, bgcolor="888888",
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, bgcolor="888888",
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, , Originally designated S190421ar.
, ,

, -
, BGCOLOR="#f0fff0", GW190424_180648
2019-04-24 18:06:48
, , 2020-10-27
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, -
, BGCOLOR="#f0fff0", GW190425
2019-04-25
08:18:05
, , 2020-01-06
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, bgcolor=AADDDD,
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, , 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.

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 ost power in sub-100 keV, or soft X-rays) bands">X-rays.html" ;"title="ost power in sub-100 keV, or soft X-rays">ost 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.
, ,
, -
, BGCOLOR="#f0fff0", GW190426_152155
2019-04-26
15:21:55
, , 2020-10-27
, ,
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, ,
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, bgcolor=aaaaaa,
, ,
, bgcolor=AADDDD,
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, bgcolor=aaaaaa,
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, ,
, , 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.
, ,
, -
, BGCOLOR="#f0fff0", GW190426_190642
2019-04-26
19:06:42
, , 2022-05-11
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, bgcolor=888888,
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, bgcolor=888888,
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, BGCOLOR="#f0fff0", GW190503_185404
2019-05-03
18:54:04
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, bgcolor=888888,
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, ,
, , Originally designated S230503bf.
, ,
, -
, BGCOLOR="#f0fff0", GW190512_180714
2019-05-12
18:07:14
, , 2020-10-27
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, ,
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, bgcolor=888888,
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, bgcolor=888888,
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, bgcolor=888888,
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, ,
, , Originally designated S230512at.
, ,
, -
, BGCOLOR="#f0fff0", GW190513_205428
2019-05-13
20:54:28
, , 2020-10-27
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, ,
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, bgcolor=888888,
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, bgcolor=888888,
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, bgcolor=888888,
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, ,
, , Originally designated S230513bm.
, ,
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, BGCOLOR="#f0fff0", GW190514_065416
2019-05-14
06:54:16
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, BGCOLOR="#f0fff0", GW190517_055101
2019-05-17
06:54:16
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, ,
, , Originally designated S190517h.
, ,
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, BGCOLOR="#f0fff0", GW190519_153544
2019-05-19
15:35:44
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, bgcolor=888888,
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, ,
, , Originally designated S190519bj.
, ,
, -
, BGCOLOR="#f0fff0", GW190521
2019-05-21
03:02:29
, , 2020-09-02
, ,
, ,

, ,
, ,
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, bgcolor=888888,
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, bgcolor=888888,
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, bgcolor=888888,
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, ,
, , Originally designated S190521g. Largest progenitor masses to date.
, ,

, -
, BGCOLOR="#f0fff0", GW190521_074359
2019-05-21
07:43:59
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, bgcolor=888888,
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, ,
, , Originally designated S190521r.
, ,
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, BGCOLOR="#f0fff0", GW190527_092055
2019-05-27
09:20:55
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, BGCOLOR="#f0fff0", GW190602_175927
2019-06-02
17:59:27
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, bgcolor=888888,
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, ,
, , Originally designated S190602aq.
, ,
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, BGCOLOR="#f0fff0", GW190620_030421
2019-06-20
03:04:21
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, BGCOLOR="#f0fff0", GW190630_185205
2019-06-30
18:52:05
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, , Originally designated S190630ag.
, ,
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, BGCOLOR="#f0fff0", GW190701_203306
2019-07-01
20:33:06
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, bgcolor=888888,
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, ,
, , Originally designated S190701ah.
, ,
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, BGCOLOR="#f0fff0", GW190706_222641
2019-07-06
22:26:41
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, bgcolor=888888,
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, , Originally designated S190706ai.
, ,
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, BGCOLOR="#f0fff0", GW190707_093326
2019-07-07
09:33:26
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, bgcolor=888888,
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, ,
, , Originally designated S190707q.
, ,
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, BGCOLOR="#f0fff0", GW190708_232457
2019-07-08
23:24:57
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, BGCOLOR="#f0fff0", GW190719_215514
2019-07-09
21:55:14
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, BGCOLOR="#f0fff0", GW190720_000836
2019-07-20
00:08:36
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, , Originally designated S190720a.
, ,
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, BGCOLOR="#f0fff0", GW190725_174728
2019-07-25
17:47:28
, , 2022-05-11
, ,
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, bgcolor=888888,
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, bgcolor=aaaaaa,
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, BGCOLOR="#f0fff0", GW190727_060333
2019-07-27
06:03:33
, , 2020-10-27
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, bgcolor=888888,
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, bgcolor=888888,
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, ,
, , Originally designated S190727h.
, ,
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, BGCOLOR="#f0fff0", GW190728_064510
2019-07-28
06:45:10
, , 2020-10-27
, ,
, ,
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, ,
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, bgcolor=888888,
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, bgcolor=888888,
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, , Originally designated S190728q.
, ,
, -
, BGCOLOR="#f0fff0", GW190731_140936
2019-07-31
14:09:36
, , 2020-10-27
, ,
, ,
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, ,
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, bgcolor=888888,
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, bgcolor=888888,
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, BGCOLOR="#f0fff0", GW190803_022701
2019-08-03
02:27:01
, , 2020-10-27
, ,
, ,
, ,
, ,
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, bgcolor=888888,
, ,
, bgcolor=888888,
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, BGCOLOR="#f0fff0", GW190805_211137
2019-08-05
21:11:37
, , 2022-05-11
, ,
, ,
, ,
, ,
, ,
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, bgcolor=888888,
, ,
, bgcolor=888888,
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, -
, BGCOLOR="#f0fff0", GW190814 2019-08-14 21:11:18
, , 2020-06-23
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, bgcolor="888888",
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, bgcolor="eebbbb",
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, bgcolor="888888",
, ,
, ,
, , 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.
, ,

, -
, BGCOLOR="#f0fff0", GW190828_063405
2019-08-28
06:34:05
, , 2020-10-27
, ,
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, bgcolor=888888,
, ,
, bgcolor=888888,
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, ,
, , Originally designated S190828j.
, ,
, -
, BGCOLOR="#f0fff0", GW190828_065509
2019-08-28
06:55:09
, , 2020-10-27
, ,
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, bgcolor=888888,
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, bgcolor=888888,
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, bgcolor=888888,
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, ,
, , Originally designated S190828l.
, ,
, -
, BGCOLOR="#f0fff0", GW190909_114149
2019-09-09
11:41:49
, , 2020-10-27
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor=888888,
, ,
, bgcolor=888888,
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, -
, BGCOLOR="#f0fff0", GW190910_112807
2019-09-10
11:28:07
, , 2020-10-27
, ,
, ,
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, ,
, ,
, ,
, bgcolor=888888,
, ,
, bgcolor=888888,
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, bgcolor=888888,
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0fff0", GW190915_235702
2019-09-15
23:57:02
, , 2020-10-27
, ,
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, ,
, ,
, ,
, bgcolor=888888,
, ,
, bgcolor=888888,
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, bgcolor=888888,
, ,
, ,
, , Originally designated S230915ak.
, ,
, -
, BGCOLOR="#f0fff0", GW190916_200658
2019-09-16
20:06:58
, , 2022-05-11
, ,
, ,
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, bgcolor=888888,
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, bgcolor=888888,
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, -
, BGCOLOR="#f0fff0", GW190917_114630
2019-09-17
11:46:30
, , 2022-05-11
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor=888888,
, ,
, bgcolor="eebbbb",
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, bgcolor=888888,
, ,
, ,
, ,
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, -
, BGCOLOR="#f0fff0", GW190924_021846
2019-09-24
02:18:46
, , 2020-10-27
, ,
, ,
, ,
, ,
, ,
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, bgcolor=888888,
, ,
, bgcolor=aaaaaa,
, ,
, bgcolor=888888,
, ,
, ,
, , 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.
, ,
, -
, BGCOLOR="#f0fff0", GW190925_232845
2019-09-25
23:28:45
, , 2022-05-11
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor=888888,
, ,
, bgcolor=888888,
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, bgcolor=888888,
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0fff0", GW190926_050336
2019-09-26
05:03:36
, , 2022-05-11
, ,
, ,
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, ,
, ,
, ,
, bgcolor=888888,
, ,
, bgcolor=888888,
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, bgcolor=888888,
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, ,
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, -
, BGCOLOR="#f0fff0", GW190929_012149
2019-09-29
01:21:49
, , 2020-10-27
, ,
, ,
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, ,
, ,
, ,
, bgcolor=888888,
, ,
, bgcolor=888888,
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, bgcolor=888888,
, ,
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, ,
, ,
, -
, BGCOLOR="#f0fff0", GW190930_133541
2019-09-30
13:35:41
, , 2020-10-27
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor=888888,
, ,
, bgcolor=aaaaaa,
, ,
, bgcolor=888888,
, ,
, ,
, , 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.
, ,

, -
, BGCOLOR="#f0f0ff", GW191103
2019-11-03 01:25:49
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW191105
2019-11-05 14:35:21
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S191105e.
, ,
, -
, BGCOLOR="#f0f0ff", GW191109
2019-11-09 01:07:17
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S191109d.
, ,
, -
, BGCOLOR="#f0f0ff", GW191113
2019-11-13 07:17:53
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW191126
2019-11-26 11:52:59
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW191127
2019-11-27 05:02:27
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW191129
2019-11-29 13:40:29
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S191129u.
, ,
, -
, BGCOLOR="#f0f0ff", GW191204_110529
2019-12-04 11:05:29
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW191204_171526
2019-12-04 17:15:26
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S191204r.
, ,
, -
, BGCOLOR="#f0f0ff", GW191215
2019-12-15 22:30:52
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S191215w.
, ,
, -
, BGCOLOR="#f0f0ff", GW191216
2019-12-16 21:33:38
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S191216ap.
, ,
, -
, BGCOLOR="#f0f0ff", GW191219
2019-12-19 16:31:20
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor=AADDDD,
, ,
, bgcolor="888888",
, ,
, ,
, , The event is unconfirmed due to difficulty accurately modelling the extreme mass ratio.
, ,
, -
, BGCOLOR="#f0f0ff", GW191222
2019-12-22 03:35:37
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S191222n.
, ,
, -
, BGCOLOR="#f0f0ff", GW191230
2019-12-30 18:04:58
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW200105
2020-01-05 16:24:26
, , 2021-06-29
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor=AADDDD,
, ,
, bgcolor="888888",
, ,
, ,
, , First event confirmed to be a black hole and neutron star merger. Originally designated S200105ae.
, ,
, -
, BGCOLOR="#f0f0ff", GW200112
2020-01-12 15:58:38
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S200112r.
, ,
, -
, BGCOLOR="#f0f0ff", GW200114
2020-01-14 02:08:08
, , 2022-08-18
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , 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 M_sun which was poorly modeled because of its high mass. Another study interpreted it as a somewhat smaller black hole merger taking place at the same time as a detector glitch. Both studies conclude the signal is most likely a real event, and the latter model is included in the table.
, ,
, -
, BGCOLOR="#f0f0ff", GW200115
2020-01-15 04:23:09
, , 2021-06-29
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor=AADDDD,
, ,
, bgcolor="888888",
, ,
, ,
, , Second event confirmed to be a black hole and neutron star merger. Originally designated S200115j.
, ,
, -
, BGCOLOR="#f0f0ff", GW200128
2020-01-28 02:20:11
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S200128d.
, ,
, -
, BGCOLOR="#f0f0ff", GW200129
2020-01-29 06:54:58
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S200129m.
, ,
, -
, BGCOLOR="#f0f0ff", GW200202
2020-02-02 15:43:12
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW200208_130117
2020-02-08 13:01:17
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S200208q.
, ,
, -
, BGCOLOR="#f0f0ff", GW200208_222617
2020-02-08 22:26:17
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW200209
2020-02-09 08:54:52
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW200210
2020-02-10 09:22:54
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="eebbbb",
, ,
, bgcolor="888888",
, ,
, ,
, , The secondary component, being between 2.41 and 3.30 solar masses, is an object in the mass gap.
, ,
, -
, BGCOLOR="#f0f0ff", GW200216
2020-02-16 22:08:04
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW200219
2020-02-19 09:44:15
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S200219ac.
, ,
, -
, BGCOLOR="#f0f0ff", GW200220_061928
2020-02-20 06:19:28
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW200220_124850
2020-02-20 12:48:50
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW200224
2020-02-24 22:22:34
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S200224ca.
, ,
, -
, BGCOLOR="#f0f0ff", GW200225
2020-02-25 06:04:21
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S200225q.
, ,
, -
, BGCOLOR="#f0f0ff", GW200302
2020-03-02 01:58:11
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S200302c.
, ,
, -
, BGCOLOR="#f0f0ff", GW200306
2020-03-06 09:37:14
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW200308
2020-03-08 17:36:09
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#f0f0ff", GW200311
2020-03-11 11:58:53
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S200311bg.
, ,
, -
, BGCOLOR="#f0f0ff", GW200316
2020-03-16 21:57:56
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, , Originally designated S200316bj.
, ,
, -
, BGCOLOR="#f0f0ff", GW200322
2020-03-22 09:11:33
, , 2021-11-17
, ,
, ,
, ,
, ,
, ,
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, bgcolor="888888",
, ,
, ,
, ,
, ,
, -
, BGCOLOR="#eeddff", GW230529
2023-05-29 18:15:00
, 2024-04-05
,
, ,
, ,
, ,
, ,
, ,
, bgcolor="eebbbb",
, ,
, bgcolor=AADDDD,
, ,
, ,
, ,
, ,
, , 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.
, ,

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, .

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:

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. Candidate event records can be directly accessed at the Gravitational-Wave Candidate Event Database (GraceDB). On 1 April 2019, the start of the third observation run was announced with a circular published in the public alerts tracker. 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.

The Kamioka Gravitational Wave Detector ( KAGRA) in Japan became operational on 25 February 2020, likely improving the detection and localization of future gravitational wave signals. 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.

Observation candidates from O4/2023

On 15 June 2022, LIGO announced to start the O4 observing run in March 2023. As the date got closer, engineering challenges delayed the observing run to May 2023. 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, and the Livingston and Virgo detectors' first operations beginning on May 5.

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 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.

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.

Notes

References

External links

*
*

{{Portal bar, Physics, Astronomy, Stars, Outer space

*List
Gravitational waves
Gravitational waves
Observational astronomy
Binary systems