moving groups, spectroscopic reductions

On the weekend I spent time reading Bovy's next huge tome about the moving groups, in which he demonstrates that they are far more likely to be dynamically created than to be fossils of past star-formation events, and that within the dynamical options they are more likely to be generated by transient dynamical complexity (from, for example, spiral arms and similar inhomogeneities) than from long-lived dynamical resonances. This supports suggestions by Tremaine. We hope to finish the paper within days.

I also finally worked through and sent my comments on spectro perfectionism; in short I complained about their treatment of exposure time, darks, and biases; their restriction to invertible matrices; the fact that the final output they advocate has no Bayesian generalization and is not a point estimate of any simple statistical property of the data or spectrum; their timidity about huge matrices and huge least-squares problems; and the issues of consistently modeling cosmic rays or data with non-Gaussian noise. I never have this many complaints about a paper unless I love it (with one notable exception); don't get me wrong: I love the paper.

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