Black Hole Binary Pairs:

[beecee]

Over the last couple of years or so, a cosmological discovery, perhaps the most momentous of the century, has been unveiled.Detectors, have fulfilled one of Einstein's GR greatest predictions...that of gravitational waves from coalescing binary BH pairs and also Neutron star pairs: Besides further validating GR, it of course has validated any doubts about the existence of BH's.

Here is an interesting article......

https://phys.org/news/2018-05-dozens-binaries-milky-globular-clusters.html

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A string of detections—four more binary black holes and a pair of neutron stars—soon followed the Sept. 14, 2015, observation.

Now, another detector is being built to crack this window wider open. This next-generation observatory, called LISA, is expected to be in space in 2034, and it will be sensitive to gravitational waves of a lower frequency than those detected by the Earth-bound Laser Interferometer Gravitational-Wave Observatory (LIGO).

A new Northwestern University study predicts dozens of binaries (pairs of orbiting compact objects) in the globular clusters of the Milky Way will be detectable by LISA (Laser Interferometer Space Antenna). These binary sources would contain all combinations of black hole, neutron star and white dwarf components. Binaries formed from these star-dense clusters will have many different features from those binaries that formed in isolation, far from other stars.

Read more at: https://phys.org/news/2018-05-dozens-binaries-milky-globular-clusters.html#jCp

the paper is at.......https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.191103

ABSTRACT

We explore the formation of double-compact-object binaries in Milky Way (MW) globular clusters (GCs) that may be detectable by the Laser Interferometer Space Antenna (LISA). We use a set of 137 fully evolved GC models that, overall, effectively match the properties of the observed GCs in the MW. We estimate that, in total, the MW GCs contain ∼21 sources that will be detectable by LISA. These detectable sources contain all combinations of black hole (BH), neutron star, and white dwarf components. We predict ∼7 of these sources will be BH-BH binaries. Furthermore, we show that some of these BH-BH binaries can have signal-to-noise ratios large enough to be detectable at the distance of the Andromeda galaxy or even the Virgo cluster.

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My question is relevant to the highlighted part in the article thus......."These binary sources would contain all combinations of black hole, neutron star and white dwarf components"

While its logical to contemplate how WD/BH, NS/BH, pairs evolve, what at this time is the best theoretical explanation for binary BH pairs themselves? I can think of two.......both formed from giant gravitationally  bound stellar partners,or that one BH actually captured another that apparently wandered to close. Any other explanations?

What I find more incredibly amazing is as per the Abstract, [and highlighted by me] is the ability to predict exactly how many, what type, and detectable distances ranging all the way to M31 and Virgo cluster.

Any comments?

 

Edited May 12, 2018 by beecee