super-massive black-hole binaries.

Bovy showed up for the day, in part to discuss quasar target selection with Muandet. Late in the day we discussed more general methods for determining the Solar motion relative to the full Milky Way disk, given that there is mounting evidence that the entire Solar Neighborhood is moving faster (relative to the MW Center) than the mean rotation speed.

In the late morning there was a talk by Tanaka (MPA) about binary super-massive black holes and their observability. As my loyal reader knows, I think these are more elusive than they should be: Either there are very few of them or they hide by turning off all AGN activity. Tanaka discussed all options but contributed something very interesting: His accretion models for these objects suggest that they should be UV and X-ray dark relative to typical quasars, at least in the late stages of inspiral. So we could test our ambiguous candidates by checking whether they are UV dark. He proposed several other interesting tests, most of which take new data and serious observing campaigns. At some point I found myself wondering whether ULIRGS (which show IR AGN activity and star formation) could be SMBH binaries. They are UV-poor and clearly the result of mergers.