GW190521

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GW190521
PhysRevLett.125.101102 Fig1.png
The GW event GW190521 observed by the LIGO Hanford (left), LIGO Livingston (middle), and Virgo (right) detectors
Date21 May 2019  OOjs UI icon edit-ltr-progressive.svg
Instrument LIGO, Virgo [1] [2]
Right ascension 12h 49m 42.3s [3]
Declination −34° 49′ 29″ [3]
Epoch J2000.0
Distance5,300 megaparsecs (17,000  Mly) [4]
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[ edit on Wikidata]

GW190521 (initially S190521g) [5] was a gravitational wave signal resulting from the merger of two black holes. It was possibly associated with a coincident flash of light; if this association is correct, the merger would have occurred near a third supermassive black hole. [2] [6] The event was observed by the LIGO and Virgo detectors on 21 May 2019 at 03:02:29 UTC, [7] and published on 2 September 2020. [4] [5] [8] The event had a Luminosity distance of 17 billion light years away from Earth, [note 1] [5] [9] within a 765 deg2 area [note 2] [10] towards Coma Berenices, Canes Venatici, or Phoenix. [1] [2] [6] [11]

Contents

At 85 and 66 solar masses (M☉) respectively, the two black holes comprising this merger are the largest progenitor masses observed to date. [12] The resulting black hole had a mass equivalent to 142 times that of the Sun, making this the first clear detection of an intermediate-mass black hole. The remaining 9 solar masses were radiated away as energy in the form of gravitational waves. [4] [5] [8]

Physical significance

GW190521 is a significant discovery due to the masses of the resulting large black hole and of one or both of the smaller constituent black holes. Stellar evolution theory predicts that a star cannot collapse itself into a black hole of more than about 65 M☉, leaving a black hole mass gap above 65 M☉. The 85+21
−14 M☉ [note 3] and 142+28
−16 M☉ black holes observed in GW190521 are conclusively in the mass gap, indicating that it can be populated by the mergers of smaller black holes. [4]

Only indirect evidence for intermediate mass black holes, those with between 100 and 100,000 solar masses, had been observed earlier, and it was unclear how they had formed. [13] Researchers hypothesize that they form from a hierarchical series of mergers, in which each black hole is the result of successive mergers involving smaller black holes. [8]

According to discovery team member Vassiliki Kalogera of Northwestern University, "this is the first and only firm/secure mass measurement of an intermediate mass black hole at the time of its birth ... Now we know reliably at least one way [such objects can form], through the merger of other black holes." [9]

Possible electromagnetic counterpart

In June 2020, astronomers reported observations of a flash of light that might be associated with GW190521. The Zwicky Transient Facility (ZTF) reported a transient optical source within the region of the GW190521 trigger, though as the uncertainty in sky position was hundreds of square degrees, the association remains uncertain. If the two events are actually linked, the event is claimed to be the first finding of an electromagnetic source related to the merger of two black holes. [2] [3] [6] [14] Mergers of black holes do not typically emit any light. The researchers suggest that it could be explained if the merging of the two smaller black holes sent the newly formed intermediate mass black hole on a trajectory that hurtled through the accretion disk of an unrelated but nearby supermassive black hole, disrupting the disk material and producing a flare of light. The newly formed black hole would have traveled at 200 km/s (120 mi/s) through the disk, according to the astronomers. [15] If this explanation is correct, the flare should repeat after about 1.6 years [3] when the intermediate mass black hole again encounters the accretion disk. [15] As of 2023, the status of the connection between these two events is unconfirmed. [16]

According to Matthew Graham, lead astronomer for the study, "This supermassive black hole was burbling along for years before this more abrupt flare. The flare occurred on the right timescale, and in the right location, to be coincident with the gravitational-wave event. In our study, we conclude that the flare is likely the result of a black hole merger, but we cannot completely rule out other possibilities." [15]

Possible eccentricity

While the original LIGO/Virgo data analysis assumed a quasi-circular inspiral waveform model, subsequent publications claimed that this source could have been significantly eccentric. Romero-Shaw et al. showed that the data is better described by a non-precessing eccentric waveform with than a spin-precessing quasi-circular model. [17] Using eccentric waveforms based on numerical relativity, Gayathri et al. 2020 found a best fit with and source masses 102+7
−11 M☉ for both merging black holes. [18]

See also

Notes

  1. ↑ "The event unfolded at an almost unimaginable distance from Earth — in a spot that is now 17 billion light-years away according to standard cosmological calculations that describe an expanding universe." [9]
  2. ↑ The relatively large and distant area of the sky within which it is claimed to be possible to localize the source.
  3. ↑ This notation is used to state asymmetric uncertainty.

Related Research Articles

<span class="mw-page-title-main">Black hole</span> Object that has a no-return boundary

A black hole is a region of spacetime where gravity is so strong that nothing, not even light and other electromagnetic waves, is capable of possessing enough energy to escape it. Einstein's theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of no escape is called the event horizon. A black hole has a great effect on the fate and circumstances of an object crossing it, but it has no locally detectable features according to general relativity. In many ways, a black hole acts like an ideal black body, as it reflects no light. Quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is of the order of billionths of a kelvin for stellar black holes, making it essentially impossible to observe directly.

<span class="mw-page-title-main">LIGO</span> Gravitational wave observatory site

The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a large-scale physics experiment and observatory designed to detect cosmic gravitational waves and to develop gravitational-wave observations as an astronomical tool. Two large observatories were built in the United States with the aim of detecting gravitational waves by laser interferometry. These observatories use mirrors spaced four kilometers apart to measure changes in length—over an effective span of 1120 km—of less than one ten-thousandth the charge diameter of a proton.

The Schwarzschild radius or the gravitational radius is a physical parameter in the Schwarzschild solution to Einstein's field equations that corresponds to the radius defining the event horizon of a Schwarzschild black hole. It is a characteristic radius associated with any quantity of mass. The Schwarzschild radius was named after the German astronomer Karl Schwarzschild, who calculated this exact solution for the theory of general relativity in 1916.

<span class="mw-page-title-main">Supermassive black hole</span> Largest type of black hole

A supermassive black hole is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (M☉). Black holes are a class of astronomical objects that have undergone gravitational collapse, leaving behind spheroidal regions of space from which nothing can escape, including light. Observational evidence indicates that almost every large galaxy has a supermassive black hole at its center. For example, the Milky Way galaxy has a supermassive black hole at its center, corresponding to the radio source Sagittarius A*. Accretion of interstellar gas onto supermassive black holes is the process responsible for powering active galactic nuclei (AGNs) and quasars.

<span class="mw-page-title-main">Laser Interferometer Space Antenna</span> European space mission to measure gravitational waves

The Laser Interferometer Space Antenna (LISA) is a planned space probe to detect and accurately measure gravitational waves—tiny ripples in the fabric of spacetime—from astronomical sources. LISA will be the first dedicated space-based gravitational-wave observatory. It aims to measure gravitational waves directly by using laser interferometry. The LISA concept features three spacecraft arranged in an equilateral triangle with each side 2.5 million kilometers long, flying in an Earth-like heliocentric orbit. The distance between the satellites is precisely monitored to detect a passing gravitational wave.

<span class="mw-page-title-main">Intermediate-mass black hole</span> Class of black holes with a mass range of 100 to 100000 solar masses

An intermediate-mass black hole (IMBH) is a class of black hole with mass in the range of tens to tens thousand (102–105) solar masses: significantly higher than stellar black holes but lower than the tens thousand to hundreds trillion (105–1015) solar mass supermassive black holes. Several IMBH candidate objects have been discovered in the Milky Way galaxy and others nearby, based on indirect gas cloud velocity and accretion disk spectra observations of various evidentiary strength.

<span class="mw-page-title-main">Stellar black hole</span> Black hole formed by a collapsed star

A stellar black hole is a black hole formed by the gravitational collapse of a star. They have masses ranging from about 5 to several tens of solar masses. They are the remnants of supernova explosions, which may be observed as a type of gamma ray burst. These black holes are also referred to as collapsars.

<span class="mw-page-title-main">Gravitational wave background</span> Random background of gravitational waves permeating the Universe

The gravitational wave background is a random background of gravitational waves permeating the Universe, which is detectable by gravitational-wave experiments, like pulsar timing arrays. The signal may be intrinsically random, like from stochastic processes in the early Universe, or may be produced by an incoherent superposition of a large number of weak independent unresolved gravitational-wave sources, like supermassive black-hole binaries. Detecting the gravitational wave background can provide information that is inaccessible by any other means about astrophysical source population, like hypothetical ancient supermassive black-hole binaries, and early Universe processes, like hypothetical primordial inflation and cosmic strings.

<span class="mw-page-title-main">Gravitational wave</span> Propagating spacetime ripple

Gravitational waves are transient displacements in a gravitational field—generated by the motion or acceleration of gravitating masses—that radiate outward from their source at the speed of light. They were first proposed by Oliver Heaviside in 1893 and then later by Henri Poincaré in 1905 as the gravitational equivalent of electromagnetic waves. In 1916, Albert Einstein demonstrated that gravitational waves result from his general theory of relativity as ripples in spacetime.

<span class="mw-page-title-main">Gravitational-wave astronomy</span> Branch of astronomy using gravitational waves

Gravitational-wave astronomy is a subfield of astronomy concerned with the detection and study of gravitational waves emitted by astrophysical sources.

A hypercompact stellar system (HCSS) is a dense cluster of stars around a supermassive black hole that has been ejected from the center of its host galaxy. Stars that are close to the black hole at the time of the ejection will remain bound to the black hole after it leaves the galaxy, forming the HCSS.

<span class="mw-page-title-main">Binary black hole</span> System consisting of two black holes in close orbit around each other

A binary black hole (BBH), or black hole binary, is a system consisting of two black holes in close orbit around each other. Like black holes themselves, binary black holes are often divided into stellar binary black holes, formed either as remnants of high-mass binary star systems or by dynamic processes and mutual capture; and binary supermassive black holes, believed to be a result of galactic mergers.

In astrophysics, the chirp mass of a compact binary system determines the leading-order orbital evolution of the system as a result of energy loss from emitting gravitational waves. Because the gravitational wave frequency is determined by orbital frequency, the chirp mass also determines the frequency evolution of the gravitational wave signal emitted during a binary's inspiral phase. In gravitational wave data analysis, it is easier to measure the chirp mass than the two component masses alone.

<span class="mw-page-title-main">Extreme mass ratio inspiral</span>

In astrophysics, an extreme mass ratio inspiral (EMRI) is the orbit of a relatively light object around a much heavier object, that gradually spirals in due to the emission of gravitational waves. Such systems are likely to be found in the centers of galaxies, where stellar mass compact objects, such as stellar black holes and neutron stars, may be found orbiting a supermassive black hole. In the case of a black hole in orbit around another black hole this is an extreme mass ratio binary black hole. The term EMRI is sometimes used as a shorthand to denote the emitted gravitational waveform as well as the orbit itself.

<span class="mw-page-title-main">First observation of gravitational waves</span> 2015 direct detection of gravitational waves by the LIGO and VIRGO interferometers

The first direct observation of gravitational waves was made on 14 September 2015 and was announced by the LIGO and Virgo collaborations on 11 February 2016. Previously, gravitational waves had been inferred only indirectly, via their effect on the timing of pulsars in binary star systems. The waveform, detected by both LIGO observatories, matched the predictions of general relativity for a gravitational wave emanating from the inward spiral and merger of a pair of black holes of around 36 and 29 solar masses and the subsequent "ringdown" of the single resulting black hole. The signal was named GW150914. It was also the first observation of a binary black hole merger, demonstrating both the existence of binary stellar-mass black hole systems and the fact that such mergers could occur within the current age of the universe.

<span class="mw-page-title-main">GW170817</span> Gravitational-wave signal detected in 2017

GW170817 was a gravitational wave (GW) signal observed by the LIGO and Virgo detectors on 17 August 2017, originating from the shell elliptical galaxy NGC 4993, about 140 million light years away. The signal was produced by the last moments of the inspiral process of a binary pair of neutron stars, ending with their merger. It was the first GW observation to be confirmed by non-gravitational means. Unlike the five previous GW detections—which were of merging black holes and thus not expected to produce a detectable electromagnetic signal—the aftermath of this merger was seen across the electromagnetic spectrum by 70 observatories on 7 continents and in space, marking a significant breakthrough for multi-messenger astronomy. The discovery and subsequent observations of GW170817 were given the Breakthrough of the Year award for 2017 by the journal Science.

<span class="mw-page-title-main">NGC 4993</span> Galaxy in the constellation of Hydra

NGC 4993 is a lenticular galaxy located about 140 million light-years away in the constellation Hydra. It was discovered on 26 March 1789 by William Herschel and is a member of the NGC 4993 Group.

GW 190412 was a gravitational wave (GW) signal observed by the LIGO and Virgo detectors on 12 April 2019. In April 2020, it was announced as the first time a collision of a pair of very differently sized black holes has been detected. As a result of this asymmetry, the signal included two measurable harmonics with frequencies approximately a factor 1.5 apart.

<span class="mw-page-title-main">GW190814</span> Gravitational wave of a "mass gap" collision

GW 190814 was a gravitational wave (GW) signal observed by the LIGO and Virgo detectors on 14 August 2019 at 21:10:39 UTC, and having a signal-to-noise ratio of 25 in the three-detector network. The signal was associated with the astronomical super event S190814bv, located 790 million light years away, in location area 18.5 deg2 towards Cetus or Sculptor. No optical counterpart was discovered despite an extensive search of the probability region.

References

  1. 1 2 "Superevent info - S190521g". LIGO . 21 May 2019. Archived from the original on 28 June 2020. Retrieved 25 June 2020.
  2. 1 2 3 4 Cofield, Calla (25 June 2020). "Black Hole Collision May Have Exploded With Light". NASA . Archived from the original on 28 June 2020. Retrieved 25 June 2020.
  3. 1 2 3 4 Graham, M.J.; et al. (2020). "Candidate Electromagnetic Counterpart to the Binary Black Hole Merger Gravitational-Wave Event S190521g" (PDF). Physical Review Letters . 124 (25): 251102. arXiv: 2006.14122 . Bibcode:2020PhRvL.124y1102G. doi:10.1103/PhysRevLett.124.251102. PMID   32639755. S2CID   220055995. Archived (PDF) from the original on 11 July 2020. Retrieved 5 September 2020.
  4. 1 2 3 4 Abbott, R.; et al. (2 September 2020). "Properties and Astrophysical Implications of the 150 M ⊙ Binary Black Hole Merger GW190521". The Astrophysical Journal . 900 (1): L13. arXiv: 2009.01190 . Bibcode:2020ApJ...900L..13A. doi: 10.3847/2041-8213/aba493 .
  5. 1 2 3 4 Abbott, R.; et al. (2 September 2020). "GW190521: A Binary Black Hole Merger with a Total Mass of 150 M ⊙". Physical Review Letters . 125 (10): 101102. arXiv: 2009.01075 . Bibcode:2020PhRvL.125j1102A. doi: 10.1103/PhysRevLett.125.101102 . PMID   32955328.
  6. 1 2 3 Overbye, Dennis (25 June 2020). "Two Black Holes Colliding Not Enough? Make It Three - Astronomers claim to have seen a flash from the merger of two black holes within the maelstrom of a third, far bigger one". The New York Times . Archived from the original on 25 June 2020. Retrieved 25 June 2020.
  7. ↑ "GW trigger S190521g ('GW 190521')". University of Leicester . 2020. Archived from the original on 28 June 2020. Retrieved 26 June 2020.
  8. 1 2 3 Martin (2 September 2020). "GW190521: The Most Massive Black Hole collision Observed To Date" (PDF). LIGO Scientific Collaboration . Archived (PDF) from the original on 4 September 2020. Retrieved 2 September 2020.
  9. 1 2 3 Overbye, Dennis (3 September 2020). "These Black Holes Shouldn't Exist, but There They Are - On the far side of the universe, a collision of dark giants sheds light on an invisible process of cosmic growth". The New York Times . Archived from the original on 2 September 2020. Retrieved 4 September 2020.
  10. ↑ Mo, Geoffrey (21 May 2020). "GCN Circular - Number: 24640 - LIGO/Virgo S190521g: Updated sky localization". NASA . Archived from the original on 27 June 2020. Retrieved 27 June 2020.
  11. ↑ Graduate Center, CUNY (25 June 2020). "Black hole collision may have exploded with light". Phys.org . Archived from the original on 26 June 2020. Retrieved 26 June 2020.
  12. ↑ Siegel, Ethan (3 September 2020). "LIGO's Biggest Mass Merger Ever Foretells A Black Hole Revolution". Forbes . Archived from the original on 4 September 2020. Retrieved 5 September 2020.
  13. ↑ Miller, M. Coleman; Colbert, E. J. M. (2004). "Intermediate-Mass Black Holes". International Journal of Modern Physics D. 13 (1): 1. arXiv: astro-ph/0308402 . Bibcode:2004IJMPD..13....1M. doi:10.1142/S0218271804004426. S2CID   118959484.
  14. ↑ "Black hole collision may have exploded with light". ScienceDaily . 26 June 2020. Archived from the original on 26 June 2020. Retrieved 26 June 2020.
  15. 1 2 3 Carpineti, Alfredo (25 June 2020). "Astronomers May Have Observed The First Flare From A Black Hole Collision". IFLScience . Archived from the original on 29 June 2020. Retrieved 26 June 2020.
  16. ↑ Cui, Zhe; Li, Xiang-Dong (16 June 2023). "On the formation of GW190521-like binary black hole merger systems". Monthly Notices of the Royal Astronomical Society. 523 (4): 5565–5582. arXiv: 2306.08441 . doi: 10.1093/mnras/stad1800 . ISSN   0035-8711.
  17. ↑ Romero-Shaw, I.; et al. (23 October 2020). "GW190521: Orbital Eccentricity and Signatures of Dynamical Formation in a Binary Black Hole Merger Signal". The Astrophysical Journal . 903 (1): 5. arXiv: 2009.04771 . Bibcode:2020ApJ...903L...5R. doi: 10.3847/2041-8213/abbe26 .
  18. ↑ Gayathri, V.; et al. (2020). "GW190521 as a Highly Eccentric Black Hole Merger". arXiv: 2009.05461 [astro-ph.HE].
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