2014-12-12

redshift probability, lensed supernova, interstellar metallicity

At group meeting, Alex Malz showed some first results on using redshift probability distributions in a (say) luminosity function analysis. He showed that he gets different results if he takes the mean of the redshift pdf or the mode or does something better than either of those. I asked him to write that up so we can see if we all agree what "better" is. Fadely handed me a draft of his work to date on the star–galaxy separation stuff he has been working on.

After group meeting, at journal club, Or Graur (NYU) showed work he has been doing on a multiply imaged supernova. It looks very exciting, and it is multiply imaged by a galaxy in a lensing cluster, so there are actually something like seven or eight possibly detectable images of the supernova, some possibly with substantial time delays. Very cool.

The astro seminar was by Christy Tremonti (Wisconsin), who told us about gas and metallicity in galaxy disks. She has some possible evidence—in the form of gradients in effective yield and gas-to-star ratio—that the gas is being moved around the galaxy by galactic fountains. She is one of the first users of the SDSS-IV MaNGA integral-field data, so that was particularly fun to see.

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