MPA SN meeting, day 3

I’m not doing a particularly good job of keeping these short. Or posting them on time. I’m not even in Munich anymore (as of 16 September). Oh well, I’ll do my best to catch up here.


  • Ryan Foley talked about “Iax” (what we used to call “2002cx-likes”), claiming they can be explained by the ignition of a helium layer on the surface of a white dwarf which doesn’t quite disrupt it. They are faint events with Ia-like spectra which never quite go “nebular”: while you can take a spectrum of one of these things at late times, you apparently have to wait much longer than you might think for the innermost layers to go transparent and allow you to see all the way into the heart of the explosion. There was some debate about whether Ryan was claiming too much or whether this deserved an entirely separate class of events. In the poster session afterwards, Curtis McCully presented an alternate view of 2002cx-like events as pure deflagrations of white dwarfs.
  • RĂ¼diger Pakmor unveiled the latest results on the violent double-degenerate mergers Ashley plugged on day 2. He’s published showing they can explain the faintest SNe Ia and also typical-brightness SNe Ia, for reasonable values of “explain”. In those papers there is still some approximation going around to get the final detonation to occur, and the mechanism only worked for pairs of white dwarfs with a nearly equal mass ratio. This time he talked about adding a helium layer to his previous scenario; it turns out adding helium makes it much easier to blow up the merger, meaning it works for any mass ratio now. There was some skepticism but there usually is, it’s our job.
  • Craig Wheeler talked about spectropolarimetry and how useful it could be for sorting out our ideas about SN asymmetry. For a good write-up of spectropolarimetry and how it’s supposed to work, check out this recent paper (a result, not a review).


I got together with Stefan Taubenberger and Markus Kromer to figure out how to move forward on the bolometric light curve studies I’m still working on. After this was the conference banquet, at which Wolfgang Hillebrandt gave a speech berating us for publishing so many papers in the last ten years without actually resolving the deep questions in the field. (This is mostly because the new wide-area surveys have added a whole new variety of fascinating transients to study. We need an Eightfold Way for supernovae.)

Also, they had sage-butter gnocchi and tiramisu, which made it my kind of banquet.


About Richard

I'm an American scientist who is building a new life in Australia. This space will contain words about science and math, but also philosophy, policy, literature, my travels, occasional rants, all sorts of things I find strange and awesome. The views expressed in this blog do not necessarily reflect the opinions of my employer at the time (currently University of Sydney), though personally, I think they should.
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