LIGO/VIRGO detect gravitational waves from neutron stars - with optical counterpart

[Strange]

https://www.ligo.caltech.edu/page/press-release-gw170817

[bimbo36]

Wow , nice news .Thanks for sharing .

[geordief]

Does that bring pinpointing the location of black hole mergers any closer?

[Strange]

One of the papers has 3500 authors. The Nobel committee need to change their rules!

http://iopscience.iop.org/article/10.3847/2041-8213/aa91c9

29 minutes ago, geordief said:

Does that bring pinpointing the location of black hole mergers any closer?

Not sure. There were several factors that made it easier to pinpoint this one. An important one is that it was near VIRGO's "blind spot" which narrowed it down.

Edited October 16, 2017 by Strange

[Memammal]

This is a pretty cool NY Times article and video re this event.

[geordief]

Eventually one of these neutron mergers  will  be massive enough to turn into a black hole.

 

Might that be observed and what would it tell us?

Edited October 16, 2017 by geordief

[swansont]

1 hour ago, geordief said:

Does that bring pinpointing the location of black hole mergers any closer?

Black holes have no optical signal to correlate with the GW signal. So, AFAIK, that has no effect. But VIRGO being online does, since it's a third detector.

[Strange]

29 minutes ago, geordief said:

Eventually one of these neutron mergers  will  be massive enough to turn into a black hole.

 

Might that be observed and what would it tell us?

It is not clear if that is what happened here, or not:

Quote

It remains uncertain what the product of this merger was. "It's about 2.7 solar masses, so it lies in the 'mass gap' between neutron stars and black holes. The most massive neutron stars found to date are about two solar masses, and the least massive black holes seen are five solar masses," Kasliwal said. "It's either the most massive neutron star ever seen, or the lowest mass black hole ever seen, or maybe it's a supermassive neutron star that will collapse to form a black hole. This is new territory."

https://www.space.com/38471-gravitational-waves-neutron-star-crashes-discovery-explained.html

[bimbo36]

 

 

[beecee]

2 hours ago, Strange said:

It is not clear if that is what happened here, or not:

https://www.space.com/38471-gravitational-waves-neutron-star-crashes-discovery-explained.html

Great news indeed! My tip is the merger/collision has resulted in a BH.....Should further observations be able to verify this? And will we ever reach sensitivities to detect gravitational waves from the BB itself?

[interested]

Here is more of the same, neutron star collisions.

https://phys.org/news/2017-10-gold-gravitational-sighting.html?utm_source=nwletter&utm_medium=email&utm_campaign=daily-nwletter

https://phys.org/news/2017-10-astronomers-cosmic-gold-precious-metals.html?utm_source=nwletter&utm_medium=email&utm_campaign=daily-nwletter

Supernovae are not be the source of metals heavier than iron after all, are neutron star collisions enough to explain all the heavier elements?

 

[interested]

The links show a gravitational wave was received first followed by gamma rays then various other waves at reducing energy levels, which was due to large neutron star collisions not black holes. The links also show evidence for heavier elements than iron being produced including gold and uranium, is this not the most interesting thing.  

Black holes colliding would only give off gravitational waves and perhaps gamma rays, any matter formed that could be detected would have to escape the event horizon. In these observations lots of heavy elements have been detected, which would not have been detected if they were black holes. 

[swansont]

!

Moderator Note

Black hole merger discussion has been split

http://www.scienceforums.net/topic/110935-black-hole-mergers-split-from-ligovirgo/

 

[interested]

21 hours ago, beecee said:

Great news indeed! My tip is the merger/collision has resulted in a BH.....Should further observations be able to verify this? And will we ever reach sensitivities to detect gravitational waves from the BB itself?

Scientists had known where lighter elements were synthesized — most hydrogen and helium came from the Big Bang, and elements up to iron on the periodic table are mostly forged in the cores of stars. However, the origin of half of the elements heavier than iron has been uncertain. These new findings provided the first concrete proof that such mergers are the birthplaces of half of the universe's elements that are heavier than iron, Kasliwal said.

If neutron stars only produce half of the heavier elements, where do the rest come from, black holes exploding perhaps? 

[beecee]

On 10/18/2017 at 3:22 AM, interested said:

Scientists had known where lighter elements were synthesized — most hydrogen and helium came from the Big Bang, and elements up to iron on the periodic table are mostly forged in the cores of stars. However, the origin of half of the elements heavier than iron has been uncertain. These new findings provided the first concrete proof that such mergers are the birthplaces of half of the universe's elements that are heavier than iron, Kasliwal said.

If neutron stars only produce half of the heavier elements, where do the rest come from, black holes exploding perhaps? 

BHs don't really explode: And I can't really picture Hawking Radiation as being the cause as this process would take the lifetime of the universe itself. If I may hazard a guess, perhaps the rest of the so far uncertain origin of some of the elements, may be caused by collisions of Pulsars spinning at very high rates.

[Strange]

This almost deserves its own thread. The data from neutron star mergers will help pin down the value of the Hubble constant, perhaps resolving the current discrepancy in two very different ways of measuring it: https://www.quantamagazine.org/colliding-neutron-stars-could-settle-cosmologys-biggest-controversy-20171025/

The article is also an excellent overview of the current state of the art.