Ok I was too tired last night (or rather, early this morning) to complete my report from Amsterdam/EHT “Pajama Central Command” outpost, sorry to leave the ~10 people reading this in suspense! It turned out to be quite a harrowing situation. Shep (the PI) referred to it as a more typical “angst-ridden” decision, because the earlier nights had been pretty clear what to do. By the time we reconvened at 1:00am EU time, the good news was that the weather at LMT had begun to stabilize, and SMT was still a bit marginal but good to go. But then there was an O-ring problem on one of the helium dewars at JCMT on the top of Mauna Kea, a very high, isolated mountain where there aren’t exactly spare helium dewars just lying around! So they were working on jury-rigging a solution, and then the worst of all possible things happened: the correlator on ALMA went down. For those of you unfamiliar with this acronym soup, these are all the names of the different facilities across the globe being linked together into the “Event Horizon Telescope” experiment, to make an effectively earth-sized array. ALMA is the key part of that, a newish, extremely sensitive array in its own right in Chile that sort of anchors the whole project in terms of sensitivity. Without its correlator, the communication between ALMA’s individual dishes would be down, and no ALMA means no trigger. We had 45 minutes until the deadline for the final go/nogo decision, and it all depended on someone at the ALMA site figuring out the problem. They managed to reset the correlator and got it working, and the GO came out of Central Command at 2:17am, just a scant four hours before the observations had to start, so it was a very tight call. But I’m extremely happy, this means we got two consecutive days on said favorite black hole Sgr A*, both with EHT and the Xray missions, plus I found out there was also some TeV gamma-ray coverage from H.E.S.S.. It was also just super cool to be a (minor) part of this process and I will now hold my breath for the 6 (?) months until we know our results. Not really. About the breath I mean, the 6 months is probably not a bad estimate.
To end, another beauty shot posted by David Sanchez at the LMT in Mexico:
