There is an informal meeting at MPIA every Wednesday regarding binary stars, with a bit of a focus on massive binaries. Today there was a very nice presentation by Jakob Stegmann (MPA) about some anomalies among the (only six) black-hole–neutron-star binaries discovered by NSF LIGO. He showed the example of GW 200105, which shows a large eccentricity (0.15-ish). This eccentricity is very hard to explain, given how the inspirals evolve as they radiate. But the analysis of the eccentricity (from perhaps this paper) is Bayesian, so it isn't clear how much the eccentricity result is forced by the data and how much is forced by the prior over nuisance parameters. That's one of the main points of my forthcoming paper on measurement. I think maybe I should just re-analyze this one with a profile likelihood. I hope the data and code are public!
Doesn't Figure 7 of that paper answer your question?
ReplyDeleteI believe all the GW data from the event has been public since 2021. The waveform models the paper discusses are all public, and so is the bilby library they use for the inference. I suppose the config files aren't, though.
Thank you; I will see if I can find someone who wants to get dirty. Figure 7 doesn't answer my question directly, but it does suggest that the eccentricity result contains substantial information from the prior, and is not coming primarily from the data.
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