#GW190412

[msamba]

"LIGO" - Director's Cut

Les Guthman’s director’s cut of his “LIGO” documentary. It includes a full chapter with Kip Thorne and Alessandra Buonnano on the cosmology of LIGO not seen in the original version, and a deeper history of the long 50-year search for these once-elusive messengers from the “Warped Side” of the universe: gravitational waves. Image credit: GW190412 simulation by Nils L. Fischer and Harald P.…

[blogpicturesdonalexander]

Великолепное, однобокое слияние черных дыр?

Судя ��о повторному анализу данных, однобокое слияние двух черных дыр может иметь необычное происхождение.

Для Вас читатели моего блога, сегодня рассмотрим слияние двух черных дыр. Такое слияние было впервые обнаружено 12 апреля 2019 года как гравитационная волна, которая достигла детекторов как LIGO (лазерная интерферометрическая обсерватория гравитационных волн). Ученые назвали сигнал GW190412 и определили, что он возник в результате столкновения двух черных дыр Давида и Голиафа, одна из которых в три раза массивнее другой. Этот сигнал ознаменовал первое обнаружение слияния двух черных дыр очень разных размеров. Вероятно, что более массивная из двух черных дыр сама была продуктом предыдущего слияния двух родительских черных дыр. Голиаф, появившийся в результате этого первого столкновения, мог затем рикошетить вокруг плотно упакованного «ядерного кластера» перед тем, как слиться со второй, меньшей черной дырой - хриплое событие, которое послало гравитационные волны, колеблющиеся в пространстве. Считается, что существует два основных способа образования слияний черных дыр. Первый известен как процесс с общей оболочкой, когда две соседние звезды через миллиарды лет взрываются, образуя две соседние черные дыры, которые в конечном итоге имеют общую оболочку или газовый диск. Спустя еще несколько миллиардов лет черные дыры сливаются по спирали. Другой распространенный путь, по которому сливаются черные дыры, это динамические взаимодействия. Представьте себе вместо моногамной среды галактический рейв, где тысячи черных дыр втиснуты в небольшую плотную область Вселенной. Когда две черные дыры начинают объединяться, третья может развалить пару в динамическом взаимодействии, которое может повторяться много раз, прежде чем пара черных дыр окончательно сольется. Но во вселенной, господа читатели, ничего не происходит только один раз. И что-то подобное, хотя и редко, мы увидим снова и сможем рассказать ��ольше о Вселенной. Суть в том, что оба этих сценария, которые люди традиционно считают идеальными для двойных черных дыр во Вселенной, изо всех сил пытаются объяснить соотношение масс и вращение этого события. Для начала надо смоделировать, эволюцию типичной галактики с помощью STAR TRACK, симуляции, которая отслеживает галактики на протяжении миллиардов лет, начиная со слияния газа и заканчивая тем, как звезды принимают форму и взрываются, а затем коллапсируют в черные дыры, которые в конечном итоге сливаются. Вторая модель моделирует случайные динамические встречи в шаровых скоплениях, это плотных скоплениях звезд вокруг большинства галактик. Процесс иерархического слияния может лучше объяснить однобокую массу GW190412 и его высокую скорость вращения. Если бы одна черная дыра была продуктом предыдущего спаривания двух родительских черных дыр одинаковой массы, она сама была бы массивнее любой из родительских дыр, а позже значительно затмила бы своего партнера в первом поколении, создавая высокую долю масс в окончательном слиянии. Иерархический процесс также может вызвать слияние с высоким вращением. Родительские черные дыры в их хаотическом слиянии раскрутят образовавшуюся черную дыру, которая затем перенесет это вращение в свое собственное окончательное столкновение. Если GW190412 действительно образовался в результате иерархического слияния, это событие также может пролить свет на среду, в которой он образовался. А, что если большая из двух черных дыр образовалась в результате предыдущего столкновения, это столкновение, вероятно, генерировало огромное количество энергии, которая не только раскручивала новую черную дыру, но и отбрасывала ее на некоторое расстояние. Я думаю, в этом случае, что полученного им толчка было недостаточно, чтобы покинуть звездное скопление, в котором он образовался. Если GW190412 действительно является продуктом иерархического слияния, команда подсчитала, что это могло произойти в среде со скоростью убегания выше 150 километров в секунду. Для сравнения: космическая скорость большинства шаровых скоплений составляет около 50 километров в секунду. В заключении добавлю, что любая среда, в которой возник GW190412, обладала огромным гравитационным притяжением, и я считаю, что такой средой мог быть либо газовый диск вокруг сверхмассивной черной дыры, либо «ядерный кластер» - невероятно плотная область Вселенной. , наполненный десятками миллионов звезд.

четверг, 03 сентября 2020, 11:37

[spaceexp]

This black-hole collision just made gravitational waves even more interesting

Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut) logo. 21 April 2020 An unprecedented signal from unevenly sized objects gives astronomers rare insight into how black holes spin. 

Image above: A visualization of a collision between two differently sized black holes. Image Credits: N. Fischer, H. Pfeiffer, A. Buonanno (Max Planck Institute for Gravitational Physics), Simulating eXtreme Spacetimes (SXS) Collaboration. Gravitational-wave astronomers have for the first time detected a collision between two black holes of substantially different masses — opening up a new vista on astrophysics and on the physics of gravity. The event offers the first unmistakable evidence from these faint space-time ripples that at least one black hole was spinning before merging, giving astronomers rare insight into a key property of these these dark objects. “It’s an exceptional event,” said Maya Fishbach, an astrophysicist at the University of Chicago in Illinois. Similar mergers on which data have been published all took place between black holes with roughly equal masses, so this new one dramatically upsets that pattern, she says. The collision was detected last year, and was unveiled on 18 April by Fishbach and her collaborators at a virtual meeting of the American Physical Society, held entirely online because of the coronavirus pandemic.

GW190412: Binary Black Hole Merger

The Laser Interferometer Gravitational-Wave Observatory (LIGO) — a pair of twin detectors based in Hanford, Washington, and Livingston, Louisiana — and the Virgo observatory near Pisa, Italy, both detected the event, identified as GW190412, with high confidence on 12 April 2019. The LIGO–Virgo collaboration, which includes Fishbach, posted its findings on the arXiv preprint server. LIGO made the first discovery of gravitational waves in September 2015, detecting the space-time ripples from two merging black holes. LIGO, later joined by Virgo, subsequently made ten more detections in two observing runs that ended in 2017: nine more black-hole mergers and one collision of two neutron stars, which helped to explain the origin of the Universe’s heavy chemical elements. The third and most recent run started on 1 April 2019 and ended on 27 March 2020, with a month-long break in October. Greatly improved sensitivity enabled the network to accumulate around 50 more ‘candidate events’ at a rate of roughly one per week. Until now, the international collaboration had unveiled only one other event from this observation period — a second merger between two neutron stars, dubbed GW190425, that was revealed in January. Related links: Laser Interferometer Gravitational-Wave Observatory (LIGO): https://www.ligo.caltech.edu/page/what-is-ligo Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut): https://www.aei.mpg.de/ Image (mentioned), Video, Text, Credits: Nature/Davide Castelvecchi/Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut). Greetings, Orbiter.ch Full article

[wumblr]

this is about GW190412, a black hole merger from last april featuring vastly different sizes of black hole, but this and the 142 solar mass merger product (190521g) both lend credence to the “hierarchical merger” hypothesis for stellar mass black holes, which is basically that today’s black holes are the result of many progressively larger generations of merger formation and reformation. (the alternative theories would be “isolated evolution,” where they form singularly, from binary stars and star clusters. these aren’t necessarily mutually exclusive, especially since the prevailing supermassive formation theory is something else entirely, “direct collapse” from gas too dense to form stars)

[the-telescope-times]

(via New Possible Explanation of Strange Black Hole Merger Revealed)

Scientists from the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) reveal an alternative explanation of the recently announce black hole merger. The paper was just accepted by Astrophysical Journal Letters.

On the 12th of April 2019, the LIGO and Virgo observatories detected gravitational waves—ripples in space and time—from an unusual cosmic event of two black holes merging. Unlike the ten previously reported black hole mergers, in which the two black holes may have had equal or nearly-equal masses, this event, called GW190412, definitely had two very unequal black holes, with the heavier one possibly three or four times more massive than the lighter one.

[dreampoetryvisions]

LIGO and Virgo detectors catch first gravitational wave from binary black hole merger with unequal masses. GW190412 is the first observation of a binary black hole merger where the two black holes have distinctly different masses of about 8 and 30 times that of our Sun. via /r/spaceporn https://ift.tt/34T4mQB

[astroblogs]

Voor het eerst zijn veelzeggende boventonen gezien in zwaartekrachtsgolven

  De meting van zwaartekrachtgolf GW190412. Credit: LIGO/Virgo Collaboration

De zwaartekrachtsgolf GW190412die de Virgo en twee LIGO-detectoren op 12 april 2019 waarnamen was afkomstig van een botsing tussen twee zeer verschillende zwarte gaten. Dat blijkt uit boventonen in het signaal, die vorig jaar voor het eerst zijn gemeten. Het massaverschil tussen de botsende zwarte gaten is volgens een…

[adrianusv61]

Voor het eerst zijn veelzeggende boventonen gezien in zwaartekrachtsgolven

  De meting van zwaartekrachtgolf GW190412. Credit: LIGO/Virgo Collaboration

De zwaartekrachtsgolf GW190412die de Virgo en twee LIGO-detectoren op 12 april 2019 waarnamen was afkomstig van een botsing tussen twee zeer verschillende zwarte gaten. Dat blijkt uit boventonen in het signaal, die vorig jaar voor het eerst zijn gemeten. Het massaverschil tussen de botsende zwarte gaten is volgens een…

[sachwlang]

Researchers suggest a novel process to explain the collision of a large black hole and a much smaller one -- ScienceDaily

Researchers suggest a novel process to explain the collision of a large black hole and a much smaller one — ScienceDaily

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A lopsided merger of two black holes may have an oddball origin story, according to a new study by researchers at MIT and elsewhere.

The merger was first detected on April 12, 2019 as a gravitational wave that arrived at the detectors of both LIGO (the Laser Interferometer Gravitational-wave Observatory), and its Italian counterpart, Virgo. Scientists labeled the signal as GW190412 and…

[tachtutor]

Why Can Black Hole Binaries Have Dramatically Different Masses? Multiple Generations of Mergers

Why Can Black Hole Binaries Have Dramatically Different Masses? Multiple Generations of Mergers

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On the 12th of April, 2019, the LIGO and Virgo gravitational wave observatories detected the merger of two black holes. Named GW190412, one of the black holes was eight solar masses, while the other was 30 solar masses. On the 14th of August that year, an even more extreme merger was observed, when a 2.5 solar mass object merged with a black hole nearly ten times more massive. These mergers…

[sciencenews-daily]

Check out our science blog - https://ift.tt/30CkxOD GW190412: The Merger of Two Black Holes with Unequal Masses via /r/science https://ift.tt/3aEQV82

[spaceexp]

LIGO-Virgo Finds Mystery Object in "Mass Gap"

LIGO-Virgo logo. June 24, 2020 When the most massive stars die, they collapse under their own gravity and leave behind black holes; when stars that are a bit less massive die, they explode in a supernova and leave behind dense, dead remnants of stars called neutron stars. For decades, astronomers have been puzzled by a gap that lies between neutron stars and black holes: the heaviest known neutron star is no more than 2.5 times the mass of our sun, or 2.5 solar masses, and the lightest known black hole is about 5 solar masses. The question remained: does anything lie in this so-called mass gap? Now, in a new study from the National Science Foundation's Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo detector in Europe, scientists have announced the discovery of an object of 2.6 solar masses, placing it firmly in the mass gap. The object was found on August 14, 2019, as it merged with a black hole of 23 solar masses, generating a splash of gravitational waves detected back on Earth by LIGO and Virgo. A paper about the detection has been accepted for publication in The Astrophysical Journal Letters.

Image above: In August of 2019, the LIGO-Virgo gravitational-wave network witnessed the merger of a black hole with 23 times the mass of our sun and a mystery object 2.6 times the mass of the sun. Scientists do not know if the mystery object was a neutron star or black hole, but either way it set a record as being either the heaviest known neutron star or the lightest known black hole. Image credits: LIGO/Caltech/MIT/R. Hurt (IPAC). "We've been waiting decades to solve this mystery," says co-author Vicky Kalogera, a professor at Northwestern University. "We don't know if this object is the heaviest known neutron star, or the lightest known black hole, but either way it breaks a record." "This is going to change how scientists talk about neutron stars and black holes," says co-author Patrick Brady, a professor at the University of Wisconsin, Milwaukee, and the LIGO Scientific Collaboration spokesperson. "The mass gap may in fact not exist at all but may have been due to limitations in observational capabilities. Time and more observations will tell." The cosmic merger described in the study, an event dubbed GW190814, resulted in a final black hole about 25 times the mass of the sun (some of the merged mass was converted to a blast of energy in the form of gravitational waves). The newly formed black hole lies about 800 million light-years away from Earth. Before the two objects merged, their masses differed by a factor of 9, making this the most extreme mass ratio known for a gravitational-wave event. Another recently reported LIGO-Virgo event, called GW190412, occurred between two black holes with a mass ratio of about 4:1.

LIGO-Virgo sites on the World

"It's a challenge for current theoretical models to form merging pairs of compact objects with such a large mass ratio in which the low-mass partner resides in the mass gap. This discovery implies these events occur much more often than we predicted, making this a really intriguing low-mass object," explains Kalogera. "The mystery object may be a neutron star merging with a black hole, an exciting possibility expected theoretically but not yet confirmed observationally. However, at 2.6 times the mass of our sun, it exceeds modern predictions for the maximum mass of neutron stars, and may instead be the lightest black hole ever detected." When the LIGO and Virgo scientists spotted this merger, they immediately sent out an alert to the astronomical community. Dozens of ground- and space-based telescopes followed up in search of light waves generated in the event, but none picked up any signals. So far, such light counterparts to gravitational-wave signals have been seen only once, in an event called GW170817. The event, discovered by the LIGO-Virgo network in August of 2017, involved a fiery collision between two neutron stars that was subsequently witnessed by dozens of telescopes on Earth and in space. Neutron star collisions are messy affairs with matter flung outward in all directions and are thus expected to shine with light. Conversely, black hole mergers, in most circumstances, are thought not to produce light. According to the LIGO and Virgo scientists, the August 2019 event was not seen by light-based telescopes for a few possible reasons. First, this event was six times farther away than the merger observed in 2017, making it harder to pick up any light signals. Secondly, if the collision involved two black holes, it likely would have not shone with any light. Thirdly, if the object was in fact a neutron star, its 9-fold more massive black-hole partner might have swallowed it whole; a neutron star consumed whole by a black hole would not give off any light. "I think of Pac-Man eating a little dot," says Kalogera. "When the masses are highly asymmetric, the smaller neutron star can be eaten in one bite."

LIGO-Virgo description

How will researchers ever know if the mystery object was a neutron star or black hole? Future observations with LIGO, Virgo, and possibly other telescopes may catch similar events that would help reveal whether additional objects exist in the mass gap. "This is the first glimpse of what could be a whole new population of compact binary objects," says Charlie Hoy, a member of the LIGO Scientific Collaboration and a graduate student at Cardiff University. "What is really exciting is that this is just the start. As the detectors get more and more sensitive, we will observe even more of these signals, and we will be able to pinpoint the populations of neutron stars and black holes in the universe." "The mass gap has been an interesting puzzle for decades, and now we've detected an object that fits just inside it," says Pedro Marronetti, program director for gravitational physics at the National Science Foundation (NSF). "That cannot be explained without defying our understanding of extremely dense matter or what we know about the evolution of stars. This observation is yet another example of the transformative potential of the field of gravitational-wave astronomy, which brings novel insights to light with every new detection." Webinar Series For those wishing for a deeper dive into these LIGO-Virgo results and other research from the latest observing run, the team has scheduled a webinar intended for a scientific audience. Called the LIGO-Virgo-KAGRA Webinar Series, this will be the first in a series of webinars discussing the gravitational-wave network’s results in-depth. The one-hour Zoom webinar will be on June 25 at 14:00 Universal Time Coordinated (7:00am Pacific Daylight Time; 10:00am Eastern Daylight Time; 16:00 Central European Summer Time; 23:00 Japan Standard Time). To register, visit: https://zoom.us/webinar/register/3315925939436/WN_rsJximZ8R36WqZnMH16IrA The Zoom webinar will also be live streamed and a recording will be available upon request. Additional information about the gravitational-wave observatories: LIGO is funded by the NSF and operated by Caltech and MIT, which conceived of LIGO and lead the project. Financial support for the Advanced LIGO project was led by the NSF, with Germany (Max Planck Society), the U.K. (Science and Technology Facilities Council) and Australia (Australian Research Council-OzGrav) making significant commitments and contributions to the project. Approximately 1,300 scientists from around the world participate in the effort through the LIGO Scientific Collaboration, which includes the GEO Collaboration. A list of additional partners is available at https://my.ligo.org/census.php. The Virgo Collaboration is currently composed of approximately 550 members from 106 institutes in 12 different countries including Belgium, France, Germany, Hungary, Italy, the Netherlands, Poland, and Spain. The European Gravitational Observatory (EGO) hosts the Virgo detector near Pisa in Italy, and is funded by Centre National de la Recherche Scientifique (CNRS) in France, the Istituto Nazionale di Fisica Nucleare (INFN) in Italy, and Nikhef in the Netherlands. A list of the Virgo Collaboration groups can be found at http://public.virgo-gw.eu/the-virgo-collaboration/. More information is available on the Virgo website at http://www.virgo-gw.eu. Related: GW190814 detection paper: https://iopscience.iop.org/article/10.3847/2041-8213/ab960f Virgo press release on GW190814: https://www.virgo-gw.eu/GW190814 GW190814 announcement on the LSC website: https://www.ligo.org/detections/GW190814.php Images, Text, Credits: LIGO Caltech/Whitney Clavin/MIT/Abigail Abazorius/Virgo/Livia Conti/EGO/Vincenzo Napolano/NSF/Josh Chamot. Greetings, Orbiter.ch Full article

[spiralwizardtowerlibrary]

LIGO and Virgo detectors catch first gravitational wave from binary black hole merger with unequal masses. GW190412 is the first observation of a binary black hole merger where the two black holes have distinctly different masses of about 8 and 30 times that of our Sun. via /r/spaceporn https://ift.tt/34T4mQB

[spacedude6599]

LIGO and Virgo detectors catch first gravitational wave from binary black hole merger with unequal masses. GW190412 is the first observation of a binary black hole merger where the two black holes have distinctly different masses of about 8 and 30 times that of our Sun. via /r/spaceporn. Picture posted by /u/MistWeaver80.

[spiralwizardtowerlibrarystation]

LIGO and Virgo detectors catch first gravitational wave from binary black hole merger with unequal masses. GW190412 is the first observation of a binary black hole merger where the two black holes have distinctly different masses of about 8 and 30 times that of our Sun. via /r/spaceporn https://ift.tt/34T4mQB

[entertainmentnerdly]

LIGO and Virgo detectors catch first gravitational wave from binary black hole merger with unequal masses. GW190412 is the first observation of a binary black hole merger where the two black holes have distinctly different masses of about 8 and 30 times that of our Sun. via /r/spaceporn https://ift.tt/34T4mQB