Hopefully an expert can chime in, but from what I've gathered we were fairly lucky to catch that one.
First off, it needs to happen when enough detectors are operational to get a good localization. Back then there were just three and all happened to be operational during the event. Just two won't cut it, as you can see from this[1] using just LIGO data versus this[2] which also includes VIRGO data for GW170817[3].
Next the detectors have a limited mass window they're sensitive to, with low frequencies (high mass) limited by seismic isolation and high frequencies (low mass) due to quantum effects. And the noise floor at peak sensitivity limits the maximum range to the objects.
Current sensitivity means we're at the edge of the binary-neutron star population, so we wouldn't expect to see many of those.
With more detectors coming online soon and existing ones getting further upgraded, presumably it'll not be such a rare event in the future.
A nice recent talk which touches on this was given at PIRSA here[4].
The problem is that the angular resolution is not all that great so it could've been a coincidence. With the number of observations we make and the relative frequency of supernovae anywhere, it's surprising that n isn't at least 2. Or 5.
Hopefully an expert can chime in, but from what I've gathered we were fairly lucky to catch that one.
First off, it needs to happen when enough detectors are operational to get a good localization. Back then there were just three and all happened to be operational during the event. Just two won't cut it, as you can see from this[1] using just LIGO data versus this[2] which also includes VIRGO data for GW170817[3].
Next the detectors have a limited mass window they're sensitive to, with low frequencies (high mass) limited by seismic isolation and high frequencies (low mass) due to quantum effects. And the noise floor at peak sensitivity limits the maximum range to the objects.
Current sensitivity means we're at the edge of the binary-neutron star population, so we wouldn't expect to see many of those.
With more detectors coming online soon and existing ones getting further upgraded, presumably it'll not be such a rare event in the future.
A nice recent talk which touches on this was given at PIRSA here[4].
[1]: https://dcc.ligo.org/public/0146/G1701985/001/bayestar_no_vi...
[2]: https://dcc.ligo.org/public/0146/G1701985/001/bayestar.png
[3]: https://dcc.ligo.org/LIGO-P170817/public
[4]: https://pirsa.org/25030061
The problem is that the angular resolution is not all that great so it could've been a coincidence. With the number of observations we make and the relative frequency of supernovae anywhere, it's surprising that n isn't at least 2. Or 5.
Thank you