many small things

I looked at the line emission from massive galaxies in the SDSS for a few minutes this morning, in preparation for understanding their evolution in the three-dimensional space of luminosity, color, and central stellar density. My main question is whether and how I can correct the H-alpha line equivalent widths for contributions from LINER or AGN emission to get a purer measure of the star-formation rates.

Keir Mierle (Toronto) and Dennis Zaritsky (Arizona and NYU) split group meeting today, with Mierle giving a status report on astrometry.net (which is rocking) and Zaritsky talking about the dynamical or kinematic continuum connecting elliptical galaxies to central cluster galaxies, dwarf spheroidals, and spiral galaxies (which is remarkable).

Frank van den Bosch (MPIA) gave our astro seminar on the occupation of dark matter halos by galaxies, and the predictions and power of models that describe the Universe in this way. After his talk I gave him a copy of my latest paper on galaxy environments (for bed-time reading), because he made the very nice point (with which I agree) that we should be using halo or group mass as the environment measure from now on. We will continue that discussion this summer when I am at MPIA.

Late in the day, Blanton and I went on a PRIMUS phonecon, in which we discussed the current status, which now includes some very promising redshift determinations, thanks to work by Burles, Bolton, Blanton, and Cool. We still don't have redshifts for the majority of our 300,000 spectra, but we think most of the issues come down to our throughput model, which is evolving daily.

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