WISE parallaxes, binary AGN accretion

The WISE mission took two passes over the sky. So it is nearly pessimal for parallax determination; parallaxes and proper motions are all mixed up. That said, at each pass there are multiple epochs, so maybe there is a glimmer of hope. Today, in a heroic move, Lang coded up simultaneous parallax and proper motion determination in the un-coadded WISE individual frames, a la this old paper. As expected, parallaxes are badly determined. However, we can use MCMC to explore the full degeneracy between parallax and proper motion conditioned on the WISE data, combine external information, get ready for NEOWISE (or whatever comes next), and apply any prior knowledge. I don't know if it counts as research to just cheer while someone else codes?

At lunch, Brian Farris (NYU) gave a nice talk about simulations of accretion onto merging black holes. He proposes that we might be able to see late-stage (0.1 pc ish) merging black-holes by looking for periodicities in the accretion luminosity. Oddly, the periodicity is not at the orbital frequency but instead at some lower frequency that has to do with how the disk reacts to the torques from the orbiting pair of holes.

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