MPA SN meeting, day 5

The SN-related talks went only for a half day today, and were followed after lunch by a meeting of the IAU Working Group for Supernovae regarding a unified naming and alert scheme for the LSST era.


  • Josefin Larsson gave a review of observations of the famous SN IIP 1987A — this was, as far as I’m aware, the first supernova for which a progenitor was explicitly identified from pre-explosion imaging. There is now much more information available from spatially-resolved imaging, photometry and imaging spectroscopy, taken continually throughout the history of the explosion and its remnant: the radioactive 56Ni, 57Ni and 44Ti content of the ejecta; a ring-shaped shock interaction region expanding from the center, glowing in radio and X-rays; modeling of the contents of the reverse shock; and the absence of an obvious central remnant such as a pulsar, magnetar or (accreting) black hole. All of these can be used to constrain the explosion mechanism, although the theory of explosions was covered by Bernhard Müller on Tuesday (most of that talk went over my head).
  • Laura Chomiuk gave a comprehensive review of observations of SN 2011fe, the very bright SN Ia that blew up in M101 about a year ago. We’ve been following the 2011fe-related papers closely at our SN Tea journal club at RSAA, so not many of these were new to me. Laura’s talk did, however, remind me that I could perhaps pay more attention to the constraints from radio and X-rays; my comfort zone is now solidly in the optical as far as SNe Ia are concerned.
  • Nathan Smith gave a review of “superluminous” supernovae (SLSNe), which includes a smorgasbord of very bright objects with potentially unrelated reasons for being bright: SLSNe-R (which are probably PISNe), bright SNe IIn (which could be core-collapse, like SN 2006gy, or possibly thermonuclear, like SN 2002ic), SLSNe-Ic (the 2005ap-likes or “Quimbies”). The more interesting parts of the talk for me focused on reviewing the papers modeling the ways in which, and the extent to which, shock interaction with the medium surrounding these stars could explain their extreme brightness. Roger Chevalier has had his hand in something like half of these.
  • Jeff Cooke talked about finding SLSNe at very high redshift (z < 4) by stacking images from a less-high-redshift SN Ia survey called the Supernova Legacy Survey (SNLS). Once you detect one and find out where it is, you can look back through your survey images for very faint traces of it which would have escaped your automated object finders. It’s hard work, and getting spectra of these things and their host galaxies is even harder work.
  • Maria Drout, with whom I’d talked extensively at the pub night on meeting day 1, talked about her work on a collection (we wouldn’t say “subclass” yet since data on them is sparse) of new, bright transients which rise and fall very quickly (~1 week, rather than ~1 month for more normal supernovae). Short answer is we still don’t know what they are, but I’ll talk with her about it when I hit CfA in a little bit.


I woke up for an early breakfast with Craig Wheeler talking about the funding situation in the States and whether it’ll get worse before it gets better. At the coffee break I clarified a few things with Wolfgang Hillebrandt regarding a paper I’m working on with the MPA folks. Lunch was uneventful.

After lunch, Stefan Taubenberger showed me a troubling late-time spectrum of SN 2007if which lends some credence to his idea that it may not have that much 56Ni after all. This doesn’t necessarily mean it’s not super-Chandra, but some of the arguments I used to establish its large mass might not work so well if too much of the ongoing late-time luminosity was due to a glowing shock rather than radioactive decay. He might be right, but I’m going to wait for him to write the paper before I make any final judgments.

Finally, an evening beer in the Garching beer garden with Stuart Sim, Ashley Ruiter and Ivo Seitenzahl with little Clint in tow, Ken Shen, Rüdiger Pakmor and Uli Nöbauer. Cards were played. Beer was consumed. Clint was cute again and we all went awwwww. Ashley and I went over the rewards and challenges of parenting and long-term international relationships. Then I went home and went to bed because it was flipping cold.


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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