CfA on Tuesday: Ia progenitors, “fast+brights”, and more

(Ah, I just discovered I can schedule this to be posted sometime later. That should help keep things a little more consistent. I hope.)

September 25: On Tuesday Rosanne introduced me to Alex, a visiting master’s student from Southampton (in the UK). Rosanne is interested in looking through archival X-ray data for low-energy X-ray sources or other unusual things that could conceivably be SN Ia progenitor systems. We don’t quite know exactly what we’re looking for yet, so this project, while interesting, will take some work.

While wandering around I ran into an old friend of my brother’s from high school. He did his Ph.D. in plasma physics at MIT and is now doing solar physics at the CfA! You run into people in the darndest places. We didn’t have much time to catch up, but were pleased to see each other.

I did a bit of work on the bolometric light curve paper, trying to get the near-infrared corrections right, following an idea I had on the subway last night. After churning for a while my code fell over flat, but we rarely get these things right on the first go, so I’ll try to figure out what went wrong.

I would have liked to see Dan Milisavljevic while I was here, but it turns out we got our wires crossed and he’s on an observing run this week. Hopefully next time! — he seems like a great guy with a lot of creative ideas.

While wandering around upstairs I bumped into an impromptu reception for Margaret Geller, who seems to have won a prestigious prize for her research on large-scale structure in the universe.

Later on that evening, Maria Drout found me in my office and quizzed me about some unusual events she found, which she presented at the MPA SN meeting. They’re crazy luminous at peak, rise quickly to maximum over just a few days, and their entire evolution from first rise to fading away takes only about three weeks. We went through lots of ideas about what might power them: radioactive decay of 56Ni distributed in some weird way through the ejecta? radioactive decay of some other isotopes? shock interaction, maybe with a dense shell of material? Nothing really seemed to fit perfectly.

Not only do the events have unusual light curves which are hard to explain, but that’s pretty much all the information we have on them — no X-ray, no radio, and for some events no more than one ratty spectrum. I am reminded of the Barbary et al. paper on SCP 06F6, an unusual, ultra-bright transient with a very limited data set which Quimby et al. 2011 later showed were examples of what we’ve been calling SLSNe Ic. In cases like these, the best observers may be able to do is to put their data out there and hope someone else eventually finds something that looks like it, i.e., another example which is closer, caught earlier, and with better data. But even though it’s often more satisfying to have a clear explanation and a model that fits well, papers which present baffling observations can be quite interesting and can end up being highly cited, so it’s nothing to feel bad about!


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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