2009-08-25

local standard of rest paper, black holes

[I just returned from some time off.]

I resurrected the black-hole–bulge-mass relation fitting code, made some tweaks, and got it running again after the break. On vacation I sketched out an abstract for a paper on the subject; not sure it is greater than one LPU (least publishable unit).

Bovy sent me a draft manuscript on the local standard of rest—the velocity of a putative circular orbit around the Galaxy, passing through the Solar position. He and I are arguing that this orbit does not exist, on an empirical basis. The data on the local phase-space density are simply not consistent with what is expected if that orbit exists. Of course there are approximations to this orbit; quantitatively we find that there is no such orbit at the few km/s level. There is no point in trying to measure it more accurately than that; and it shouldn't be used at all in any contexts that require precision.

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