Eric Peng (DAO, Victoria) gave a great group meeting talk about globular clusters, which separate into metal-poor and metal-rich populations. He has suggestive evidence that the metal-poor globular clusters (which probably formed at very early times) may trace the dark matter better than galaxies or stars! This would be wonderful if true, and the hypothesis makes many testable predictions.
Patrick Huggins (NYU) gave the astro seminar, about planetary nebulae. He showed that they show strong evidence for (time variable) jets, and he discussed the mysteries associated with that. He noted that a lot could be explained if all of the AGB stars that go through the PN phase are in binaries, but this seems very hard to explain in terms of the binary fraction.
Jim Pizagno (Stony Brook) talked to me about his mass images of galaxies (that is, transforming optical images into mass images using relationships between color and stellar mass-to-light ratios). He is close to a very robust system that will be of very wide applicability.
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