B LIGO's Detection of Gravitational Waves: BH-BH & BH-NS Mergers

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LIGO has detected multiple black hole (BH) mergers since the first confirmed event, GW150914, in 2015, with the O2 run identifying four mergers. The Advanced LIGO's sensitivity improvements have contributed to these findings, although the O3 run is currently on hold for upgrades. A recent LIGO news release mentioned eight candidate detections, but it remains unclear how many of these are confirmed or still under investigation. The discussion highlights the ongoing interest in the number of BH-BH and BH-neutron star (BH-NS) mergers and their alignment with predicted detection rates. Overall, LIGO continues to expand our understanding of gravitational waves and cosmic events.
wolram
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Since it's detection of GW150914, How many BH BH mergers has it detected and how many BH NS mergers has it detected, Is it living up to the potential detection's that are predicted?
 
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wolram said:
Since it's detection of GW150914, How many BH BH mergers has it detected and how many BH NS mergers has it detected, Is it living up to the potential detection's that are predicted?

Quoting myself from an earlier discussion. A-LIGO is still down for upgrades for the O3 run scheduled in the autumn.

The original LIGO equipment was much less sensitive than the Advanced LIGO that started gathering data for the first (01) run September 12, 2015 and found the first confirmed merger two days later. Before the first run was ended January, 2016 it discovered one candidate and one additional confirmed merger.

The second more sensitive O2 run started November 30, 2016 but was was suspended between May 8 and June 8 for maintenance, Virgo joined the two LIGOs on August 1 and the run was shut down August 25. This run discovered four mergers, two of them in August alone.
 
I really like the attached graphic, which shows the LIGO/VIRGO detected events and how the BH/NS masses compare to objects detected by other means.

4-ligoandvirgo.jpg
 

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phyzguy said:
I really like the attached graphic, which shows the LIGO/VIRGO detected events and how the BH/NS masses compare to objects detected by other means.

View attachment 226385
What is the horizontal axis in that graph? Time?
 
berkeman said:
What is the horizontal axis in that graph? Time?

I'm not really sure, but I don't think the horizontal axis means anything. The objects are just spread out to differentiate them. The arrows indicate the mergers.
 
Interestingly, the 7 July 2017 news release from LIGO (https://www.ligo.org/news.php) references eight candidate detections, although it's not clear whether that number includes the four detections (or five, if you count the not-sufficiently-statistically-significant event LVT151012) which had already been made public at that time. Since then, only two further detections have been made public. It would be nice to know if there are candidates still being worked on, or if they didn't pan out.
 
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