Source of LIGO's first Black Holes and Second Detection Announced.

'Mosh pits' in star clusters a likely source of LIGO's first black holes
June 15, 2016
by Megan Fellman

Northwestern University astrophysicists have predicted history. In a new study, the scientists show their theoretical predictions last year were correct: The historic merger of two massive black holes detected Sept. 14, 2015, could easily have been formed through dynamic interactions in the star-dense core of an old globular cluster.

Colliding black holes do not emit light; however, they do release a phenomenal amount of energy as gravitational waves. The first detection of these waves occurred Sept. 14, and the second—announced to the world this morning—occurred three months later. These events have launched a new era in astronomy: using gravitational waves to learn about the universe.

"Thanks to LIGO, we're not just theorists speculating anymore—now we have data," said Frederic A. Rasio, a theoretical astrophysicist at Northwestern and senior author of the study. "A relatively simple and well understood process seems to work. Simple freshman physics—Newton's first law of motion—explains the gravitational dynamics of the first black holes detected by LIGO."



Read more at: http://phys.org/news/2016-06-mosh-pits-star-clusters-source.html#jCp

 

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Gravitational waves detected from second pair of colliding black holes
June 15, 2016

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This image depicts two black holes just moments before they collided and merged with each other, releasing energy in the form of gravitational waves. On Dec. 26, 2015, after traveling for 1.4 billion years, the waves reached Earth and set off the twin LIGO detectors. This marks the second time that LIGO has detected gravitational waves, providing further confirmation of Einstein's general theory of relativity and securing the future of gravitational wave astronomy as a fundamentally new way to observe the universe. The black holes were 14 and 8 times the mass of the sun (L-R), and merged to form a new black hole 21 times the mass of the sun. An additional sun's worth of mass was transformed and released in the form of gravitational energy. Credit: Numerical Simulations: S. Ossokine and A. Buonanno, Max Planck Institute for Gravitational Physics, and the Simulating eXtreme Spacetime (SXS) project. Scientific Visualization: T. Dietrich and R. Haas, Max Planck Institute for Gravitational Physics.

On December 26, 2015 at 03:38:53 UTC, scientists observed gravitational waves—ripples in the fabric of spacetime—for the second time.

Read more at: http://phys.org/news/2016-06-gravitational-pair-colliding-black-holes.html#jCp

 

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http://iopscience.iop.org/article/1...9ECD33960206A65536B.c2.iopscience.cld.iop.org

DYNAMICAL FORMATION OF THE GW150914 BINARY BLACK HOLE

Abstract
We explore the possibility that GW150914, the binary black hole (BBH) merger recently detected by Advanced LIGO, was formed by gravitational interactions in the core of a dense star cluster. Using models of globular clusters (GCs) with detailed N-body dynamics and stellar evolution, we show that a typical cluster with a mass of

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to

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is optimal for forming GW150914-like BBHs that will merge in the local universe. We identify the most likely dynamical processes for forming GW150914 in such a cluster, and we show that the detection of GW150914 is consistent with the masses and merger rates expected for BBHs from GCs. Our results show that dynamical processes provide a significant and well-understood pathway for forming BBH mergers in the local universe. Understanding the contribution of dynamics to the BBH merger problem is a critical step in unlocking the full potential of gravitational-wave astronomy.

 

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http://physics.aps.org/articles/v9/68
extract:
The team calculates that the waves came from the merging of black holes with masses of about 14 and 8 times that of the Sun, 1.4 billion light years away. These masses are close to the typical values inferred from conventional observations of black holes orbiting ordinary stars, whereas those responsible for the first LIGO event were much larger, at 29 and 36 solar masses.

Unlike that earlier detection, the new event “did not leap out of the data,” says Sarah Caudill, a member of the LIGO team from the University of Wisconsin in Milwaukee. It became evident only after careful filtering and analysis of the data. The LIGO team has worked on this analysis in partnership with the European Virgo Collaboration—which is associated with the Virgo gravitational-wave detector near Pisa, Italy.

The second event was different from the first in several other important ways, says Caudill. The black holes were smaller, which led to different timing for the final orbits and allowed LIGO to see more of the last stages before the black holes merged—55 cycles in the new data, compared with only 10 in the earlier event. And jointly analyzing the two events permitted a more precise test for violations of general relativity, Caudill says, although no such violations were found.

 

GW151216:

Visual Simulation:


Press Release: https://www.ligo.caltech.edu/news/ligo20160615
Data Page: https://losc.ligo.org/events/GW151226/
Article: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241103

 

http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.116.241103

We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences. Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a significance greater than 5σ. The signal persisted in the LIGO frequency band for approximately 1 s, increasing in frequency and amplitude over about 55 cycles from 35 to 450 Hz, and reached a peak gravitational strain of 3.4þ0.7 −0.9 × 10−22. The inferred source-frame initial black hole masses are 14.2þ8.3 −3.7M⊙ and 7.5þ2.3 −2.3M⊙, and the final black hole mass is 20.8þ6.1 −1.7M⊙. We find that at least one of the component black holes has spin greater than 0.2. This source is located at a luminosity distance of 440þ180 −190 Mpc corresponding to a redshift of 0.09þ0.03 −0.04 . All uncertainties define a 90% credible interval. This second gravitational-wave observation provides improved constraints on stellar populations and on deviations from general relativity.

VII. CONCLUSION
LIGO has detected a second gravitational-wave signal from the coalescence of two stellar-mass black holes with lower masses than those measured for GW150914. Public data associated with GW151226 are available at [89]. The inferred component masses are consistent with values dynamically measured in x-ray binaries, but are obtained through the independent measurement process of gravitational-wave detection. Although it is challenging to constrain the spins of the initial black holes, we can conclude that at least one black hole had spin greater than 0.2. These recent detections in Advanced LIGO’s first observing period have revealed a population of binary black holes that heralds the opening of the field of gravitational-wave astronomy.

 

Here are also four papers essentially searches for data of possible optical counterpart [Gamma ray incidents] associated with these latest findings......

http://arxiv.org/abs/1606.04901

http://arxiv.org/abs/1606.04538

http://arxiv.org/abs/1606.04574

http://arxiv.org/abs/1606.04795

Nothing substantial found supporting the GR BH modelling against any possible exotic alternative.

 

This is so fantastic.I haven't read the reports yet. Hopefully there could be more GW signatures still to be found in the 'so far' collected data.. I can't wait till the next start up.

 

Agreed sweetpea. The most interesting and productive part so far though imo, was the subsequent immediate search for gamma rays, which the null results, confirm what they already knew, that we had a second episode of BH mergers.

 

The point is that can the energy of around 2 solar mass loss travel 1.3 bly...can the gamma ray radiation create observable effect on Earth ? Second point how gamma ray got produced ?

I stated to Danshaven before first detection that GW will be detected, it is just that reasons were different.

 

Firstly, on your point, re "the point is"...the point is that the experiments are successful and have been shown accurate.
Then after digesting that, perhaps you need to read the four papers properly.
The gamma signature was not evident and the original one with the first GW confirmation has already been invalidated and I posted that the other day.
Grasping at straws???

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.
But of course when we have anti science cranks that continually claim anomaly with scientific experiments, in time they may snag a correct interpretation...That happened with BICEP2.

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[They literally came out of the woodwork to say "I told you so"
Irrespective though, and notably, it was mainstream science again, that got it back on track.

 

Black holes have no concept of massed object. It is defined as

.....a region of space having a gravitational field so intense that no matter or radiation can escape.....

Now there are obvious doubts regarding the claim of GW detection....

1. What actually collides ? Curved space ? Singularity ? Some hypothetical field ?

2. To collide one or both objects will have to move, right ? So how a black hole (curved space) moves ? The movement of a Black Hole seems to contradict its definition.

3. I do not know yet, from which direction (and location) this second wave came, but can BH collission be so frequent.

4. MW is hardly a lac light years across, 1.3 Bly suggests a different Galaxy, did we know before hand that look there will be two BHs in that area and they will collide ?

5. Is it not too much that a less than noise level signal is used to prove :

5.1 Existence of Binary BHs.
5.2 Mergere of BHs.
5.3 Merger Mechanism.
5.4 Gravitational Waves.

I feel first we should establish whether two BHs can exist in such close proximity or one of them wander closer to another but how ?

6. How the gamma ray or radiation got created ? Is it of accretion material, if so that would have been eaten and digested even before merger ? If it is conversion from rotational energy, then how do you convert rotational energy into EM radiation ? What is the significance of Black Holes mass loss in this context ?

7. This is simple and local, ripples are in the spacetime not in the space, interference of light would have happened if there was a path difference, suggesting local change in the shape of space. What is the local shape of the space and how it can change ? What is so physical about space that would get rippled ? Common sense says that when you throw a stone in the water, ripples will get created, fine, some catastrophe took place in the form of merging of two BHs, but where is the water (metaphorically) ?

 

Once upon a time, In a land far far away, there lived a beautiful Princess........

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Let's have a better look at those papers on the gamma ray aspect after the preceding fairy tale......

http://arxiv.org/abs/1606.04901
We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger event GW151226 and candi- date LVT151012. No candidate electromagnetic counterparts were detected by either the GBM or LAT. We present a detailed analysis of the GBM and LAT data over a range of timescales from seconds to years, using automated pipelines and new techniques for char- acterizing the upper limits across a large area of the sky. Due to the partial GBM and LAT coverage of the large LIGO localization regions at the trigger times for both events, dif- ferences in source distances and masses, as well as the uncertain degree to which emission from these sources could be beamed, these non-detections cannot be used to constrain the variety of theoretical models recently applied to explain the candidate GBM counterpart to GW150914.


http://arxiv.org/abs/1606.04538
We report the results of a Dark Energy Camera (DECam) optical follow-up of the gravitational wave (GW) event GW151226, discovered by the Advanced LIGO detectors. Our observations cover 28.8 deg2 of the localization region in the iand z bands (containing 3% of the BAYESTAR localization probability), starting 10 hours after the event was announced and spanning four epochs at 2−24 days after the GW detection. We achieve 5σ point-source limiting magnitudes of i≈21.7 and z≈21.5, with a scatter of 0.4mag, in our difference images. Given the two day delay, we search this area for a rapidly declining optical counterpart with ≳3σ significance steady decline between the first and final observations. We recover four sources that pass our selection criteria, of which three are cataloged AGN. The fourth source is offset by 5.8 arcsec from the center of a galaxy at a distance of 187 Mpc, exhibits a rapid decline by 0.5 mag over 4 days, and has a red color of i−z≈0.3 mag. These properties roughly match the expectations for a kilonova. However, this source was detected several times, starting 94 days prior to GW151226, in the Pan-STARRS Survey for Transients (dubbed as PS15cdi) and is therefore unrelated to the GW event. Given its long-term behavior, PS15cdi is likely a Type IIP supernova that transitioned out of its plateau phase during our observations, mimicking a kilonova-like behavior. We comment on the implications of this detection for contamination in future optical follow-up observations.


http://arxiv.org/abs/1606.04574
The first direct detection of gravitational waves was made in late 2015 with the Advanced LIGO detectors. By prior arrangement, a worldwide collaboration of electromagnetic follow-up observers were notified of candidate gravitational wave events during the first science run, and many facilities were engaged in the search for counterparts. No counterparts were identified, which is in line with expectations given that the events were classified as black hole - black hole mergers. However these searches laid the foundation for similar follow-up campaigns in future gravitational wave detector science runs, in which the detection of neutron star merger events with observable electromagnetic counterparts is much more likely. Three alerts were issued to the electromagnetic collaboration over the course of the first science run, which lasted from September 2015 to January 2016. Two of these alerts were associated with the gravitational wave events since named GW150914 and GW151226. In this paper we provide an overview of the Liverpool Telescope contribution to the follow-up campaign over this period. Given the hundreds of square degree uncertainty in the sky position of any gravitational wave event, efficient searching for candidate counterparts required survey telescopes with large (~degrees) fields-of-view. The role of the Liverpool Telescope was to provide follow-up classification spectroscopy of any candidates. We followed candidates associated with all three alerts, observing 1, 9 and 17 candidates respectively. We classify the majority of the transients we observed as supernovae.


http://arxiv.org/abs/1606.04795
We present a search for an electromagnetic counterpart of the gravitational wave source GW151226. Using the Pan-STARRS1 telescope we mapped out 290 square degrees in the optical i_ps filter over a period starting 11.45hr after the LIGO information release (49.48hr after the GW trigger) and lasting for a further 28 days. We typically reached sensitivity limits of i_ps=20.3-20.8 and covered 26.5% of the LIGO probability skymap. We supplemented this with ATLAS survey data, reaching 31% of the probability region to shallower depths of m~19. We found 49 extragalactic transients (that are not obviously AGN), including a faint transient in a galaxy at 7Mpc (a luminous blue variable outburst) plus a rapidly decaying M-dwarf flare. Spectral classification of 20 other transient events showed them all to be supernovae. We found an unusual transient, PS15dpn, with an explosion date temporally coincident with GW151226 which evolved into a type Ibn supernova. The redshift of the transient is secure at z=0.1747 +/- 0.0001 and we find it unlikely to be linked, since the luminosity distance has a negligible probability of being consistent with that of GW151226. In the 290 square degrees surveyed we therefore do not find a likely counterpart. However we show that our survey strategy would be sensitive to NS-NS mergers producing kilonovae at D <~ 100 Mpc, which is promising for future LIGO/Virgo searches.
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And still we have posters continuing with fairy tale nonsense as at post 13:
With the confirmation now of two incidents of merging BH's, each different mass perspectives, and the further world wide research on the possibility of gamma radiation which might indicate something other than GR type BH's [in fact even more exotic] if it had been confirmed, the promise of even more incredible observations when aLIGO comes back on line, is near certain.

What personally excites me is the results of the four experiments searching for GRB, which showed how the Universe is apparently awash with fossil fields of many past events including supernova.
That alone holds immense promise for future data and knowledge of the Universe around us.
The future looks promising.

 

Before our fairy tale Author sees fit again to give any mythical views.....
Any GRB that is detected as associated with BH/BH merger, does not necessarily invalidate that specific merger: Accretion disks would be a source of GRB if it was associated with such mergers.

 

Paddoboy,

There was an arxiv paper by Laura Mercini....you declared that as trash. Now you are pushing papers from the same bank ? Anything which aligns with mainstream is fine anything against is trash, that's quite slavish.

 

She has now probably realised how stupid she was. That of course was well before the two confirmations of GW's and BH's, and besides, her paper did not have any support.
There are many arXiv papers on hypotheticals by the way, and they remain as hypothetical.
Your basic error is you are incapable of distinguishing between them.

 

She has not....

 

Of course she has!

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Her paper was [1] submitted years before the GW/BH confirmations, and [2] was focused on quantum aspects such as Hawking radiation, and [3] Has had little or no impact on the cosmology of BH's.
Sorry about that my friend.
ps; Her nonsense also was quickly refuted.......so find a new heroin.

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https://briankoberlein.com/2014/09/25/yes-virginia-black-holes/
Recent headlines have proclaimed “Black Holes Don’t Exist!” They’re wrong. Black holes absolutely exist. We know this observationally. We know by the orbits of stars in the center of our galaxy that there is a supermassive black hole in its center. We know of binary black hole systems. We’ve found the infrared signatures of more than a million black holes. We know of stellar mass black holes, and intermediate mass black holes. We can even see a gas cloud ripped apart by the intense gravity of a black hole. And we can take images of black holes, such as the one above. Yes, Virginia, there are black holes.

So what’s with the headlines? It seems to start with a link-bait article about a new work concerning the formation of stellar mass black holes. The paper hasn’t been peer reviewed, but it is an extension of an earlier work by the same authors that has been peer reviewed. The focus of both of these papers is on the firewall paradox, specifically how Hawking radiation might affect the gravitational collapse of a star to form a black hole.

 

True, orbital motion of nearby stars can be used, but what about G2 cloud.
There was lot of noise that it will be eaten, but no whisper. So the options were either sacrifice BH or sacrfice G2. No need to gues further, they sacrificed G2 !

Paddoboy, there are no Black Holes in nature as envisaged.