LIGO and VIRGO team up to 'hear' another black hole merger.

[bornagainathiest]

https://www.nsf.gov/news/news_summ.jsp?cntn_id=243239

 

http://www.ligo.org/news.php

 

https://profmattstrassler.com/2017/09/27/ligo-and-virgo-announce-a-joint-observation-of-a-black-hole-merger/

 

 

In a nutshell, when LIGO was working alone it didn't have the sensitivity to pinpoint where in the sky it was detecting black hole mergers.

It could only narrow the location down to a broad band, making it impossible for optical, infrared or radio telescopes to get a fix on the event.  But now that LIGO (in the US) and Virgo (in Italy) are working together they can triangulate their detected signals and zero in on a much smaller target area - giving other scopes a better chance of seeing the event.   Please note how much smaller the latest detection target area (GW170814) is compared to the four earlier, LIGO-only detections.

 

Thanks,

 

BAA. 

[pantheory]

The search for two black holes merging is interesting. Since black holes are supposed to be generally invisible to telescopic vision one would expect to see nothing visually. There might be radio waves or UV emissions coming from such a merger so one might expect they are searching out all considered possibilities. The articles also mention that there are additional investigations to further eliminate terrestrial possibilities as being the source of these signals. The funny thing about it is that if through all their additional investigations they still observe nothing at all, it will be further confirmation of their theory that they have been observing the merger of black holes, possibly neutron stars, or combinations thereof. Not bad general theory though, IMO.

 

 

[bornagainathiest]

Pantheory,

 

As you say, black hole mergers are essentially 'invisible' events.

While gravitational wave detectors like LIGO and Virgo can 'hear' them, they also have the design capacity to detect extremely visible events like core-collapse supernovae.   Please follow this link... http://rhcole.com/apps/GWplotter/  This handy graphic displays the sensitivity of eighteen different gravitational wave detectors across three different types of measurement; Characteristic Strain, Power Spectral Density and Energy Spectrum.  These being different aspects of the gravitational waves themselves.  Lower down are eleven different sources of gravitational waves, grouped according to the frequency of their output. 

 

If you select only Core collapse supernovae from the high-frequency source group and then select only aLIGO - 01 sensitivity and AdV you can see that these two detectors (LIGO and Advanced Virgo) are capable of detecting all three aspects of the gravitational waves given off from such an event.  What this means is that when such a supernova occurs we'll be able to study it in three diverse ways.  Using electromagnetic radiation, using gravitational waves and using particle physics.  The first option will be covered by the many and various telescopes (optical, radio, UV, Infrared, etc.) at out disposal.  The second by the likes of LIGO and Virgo and the third by our neutrino detectors.  https://en.wikipedia.org/wiki/Neutrino_detector

 

We've come a long way since https://en.wikipedia.org/wiki/SN_1987A and I just hope that when one of these 'pops' I'll still be around to see it.

 

Thanks,

 

BAA.