The research highlight of the day was a couple of hours spent with the iPTA data analysis collaboration. Justin Ellis (WVU) led an overview and extremely interactive discussion of their likelihood function, which they use to detect the gravitational radiation stochastic background from pulsar timing, in the presence of systematic nuisances. These include time-variable dispersion measure, red noise, accelerations and spin-down, receiver and backend calibrations, ephemeris issues, and more! The great cleverness is that they linearize and apply Gaussian priors, so they can make use of all the beautiful linear algebra that my loyal reader hears so much about. The likelihood function is a thing of beauty, and computationally tractable. They asked me for advice, but frankly, I’m not worthy.