New schedule for the next gravitaonal wave obersvation run (Kilonovae !!!)

American Association of Variable Star Observers (AAVSO)
Thu, 02/09/2023 - 19:48

One of the holy grails of "multimessenger astronomy" is the observation of a merger of two neutron stars resulting in a "kilonova" event. The event is observable in visible light, but to be sure it was really a merger of two neutron stars, you need to detect the gravitational waves generated during the merger. So this is a ideal use case for pro-am collaborations like the KILONOVA-CATCHERS discussed also in this forum: once the professional gravitational wave detectors issue public alarms about an event, amateurs can use their optical telescope to search for the optical counterpart.

The only gravitational wave detectors sensitive enough to measure those events at a reasonable event rate are located in the USA (LIGO Livingston and LIGO Hanford) and Italy (VIRGO) and are currently undergoing upgrades. It was initially planned to start a  new observation run with these instruments in March 2023, but it was now announced that because of delays in upgrading the instruments, the next observation run is scheduled to start in earnest near the end of May 2023.

All the details are documented here :

It is worth noting that compared to the previous run, public alarms will be generated even for events that are more likely to be false alarms (not astrophysical events but caused by noise in the detectors etc). So if you want to follow up all the public alarms, you'll be quite busy. But the public alarms carry information about the probability of the event being "real", so if you feel overloaded you can always focus on the more "gold plated" events that are most likely to be astrophysical.

The other big change of plans is that the next observation run is planned to last for 18 months of data collection, interrupted by one or two breaks of ca 1 month each. This is good news for astrophysicists who have lobbied for a longer than the usual 12 month observation run. The rationale was this: The one and only kilonova observed  in gravitational waved and optical wavelength so far dates back to 2017 and prompted much research into these events. No such event was observed since then, and it would be extremely unfortunate if again no such event was observed during the next run, because future updates to the detectors would then delay the second observation of a kilonova to the year 2027 or later, a full decade after the first event: enough time to spend a whole career in academia hunting for these events in vain. Making the next run 18 months long instead of 12 months increases the chance that astrophysicists will be able to test their theories against a second kilonova observation. And it increases our (amateur astronomers) chance to catch this rare kind of event. That was certainly not the reason why the run was prolonged, but it is a nice side-effect!