https://www.ligo.caltech.edu/news/ligo20220617
https://www.ligo.caltech.edu/system/new ... 1655496295
Well, not surprisingly, the startup of the 04 LIGO observation run has been delayed again, but it's getting closer, slowly but surely.
I think I'll use this pregnant pause to note that Virgo seems to have been upgraded more significantly than LIGO, and upgraded to the point that it should be quite helpful in pinpointing any sort of directional components of an observed "event" to a relatively constrained region of the sky, instead of a large circular 'swath' in previous runs. That's very encouraging IMO.
Kagra still looks to be a bit of a bust in that respect in the 04 run, unless the distance to the event is quite small. Even that small window of opportunity may prove interesting however if the 'event' is actually caused from a more localized process, like an upper atmospheric discharge, which occurs very close to Kagra, and is also observed in the other three detectors.
It should be noted that to date, the only supposed NS/NS merger observed by LIGO included a 2 second delay between the LIGO signal (observed in only one detector) and the observed gamma ray burst. In that instance LIGO couldn't localize the event to a single "point/region" in the sky, just a relatively large 'swath'. Lots of room for error/coincidence in that one event which shouldn't necessarily be true in any future NS/NS mergers, presuming LIGO signals do of course have anything at all to do with NS/NS mergers.
*If* LIGO is correct this 04 run seems like do or die time for LIGO. They 'should' be able to pickup NS/NS mergers at fairly large distances and they "should" be able to isolate their location with a significantly greater amount of directional precision. In short, the potential for a 'coincidental" gamma ray burst should be significantly reduced if all three primary gravitation wave detectors pick up the signal.
My "prediction", as a LIGO skeptic/heretic of course, is that the 04 run will *not* produce any observed NS/NS mergers, just bucket loads of additional bogus claims about invisible black hole mergers resulting in no "multimessenger" events.
The "scientific" part of me actually hopes that LIGO/Virgo proves me wrong in the 04 run, but alas, after they flat out lied in their very first paper about no vetoes being present within an hour of the original event, when in fact the signal in question was vetoed within 18 seconds, I have no faith at all in the LIGO technology or their "word". I'm sure the 'signals' they observe are quite "real", but I suspect they're caused by high atmospheric discharges (whistler waves), not gravitational waves.
The box is closing in on LIGO IMO. As more detectors become upgraded to the point of directional usefulness, the potential of 'coincidental' gamma ray bursts occurring during LIGO signals becomes much smaller. Even if a gamma ray bursts occurs in space, it's not likely to line up well with a whistler wave observed in multiple LIGO/Virgo detectors, even if it's 'close' in terms of timing (2 seconds).
On the other hand, if LIGO *is* actually observing gravitational waves from great distances, it's possible that waves from a NS/NS merger could be picked up in all three primary detectors, and align beautifully with the resulting gamma ray burst in terms of location and timing. They could even convince a hardcore skeptic like me if their technology works as advertised.
Stay tuned.
