Searching for gravitational waves below a nanohertz

Gravitational waves with frequencies below 1 nHz are notoriously difficult to detect and fall below the typical cutoff frequency for conventional pulsar timing analyses. In this talk, I will present a new means of probing this regime through the correlation of secular drifts in pulsar timing parameters. I will show the results of searches for both continuous and stochastic signals in this regime and will discuss what future observations using this methodology may reveal about the signal recently discovered by pulsar timing collaborations at frequencies above a nanohertz.