Create 03 review/minutes/190923 authored by Gregory Ashton's avatar Gregory Ashton
# 190923
## Agenda
- GW170817: [comparison page: low-spin, fixed-sky, IMRPhenomPv2_NRTidal, with calibration](https://ldas-jobs.ligo.caltech.edu/~gregory.ashton/bilby_pe_event_samples/GW170817/comparison_lowspin/home.html)
- GW170817: future tests
- Proposed review statement
> Reviewers: Matt Pitkin & Simon Stevenson
>
> Review statement:
>
> The review of the parameter-estimation code Bilby has been completed. Full details and minutes of meetings are recorded at https://git.ligo.org/lscsoft/bilby_pipe/wikis/O3-review. Here we provide a summary of the salient points of the review.
>
> Review items pertaining to simulations
> Runs on fiducial simulated events in Gaussian noise for IMRPhenomPv2
> PP tests demonstrating the Dynesty sampler works without bias for IMRPhenomPv2 with spins up to 0.8 across a range of typical masses
> Various sanity checks, including waveform outputs, 15-dimensional Gaussians, and confirming the sampler returns the prior when the likelihood is uninformative.
>
> Review items pertaining to GW150914, GW151226, GW170814, and GW170817:
> General comments on like-for-like comparison of Bilby and LALInference
> The criteria for passing this test is that the difference between the LALInference Nest and MCMC samplers is comparable to the difference between Bilby with either of these samplers.
> Differences are noted for the spin-angles,which is due to the change in the LALSuite waveforms interface between O2 and O3. This was confirmed by looking at S190521r and by point 3 below.
> For GW170817, the comparison was made using a custom-built ROQ on the fixed-sky low-spin case, future analysis of the high-spin case is planned.
> A like-for-like comparison of IMPhenomD, IMRPhenomC, and SEOBNRv3_ROM on GW150914, demonstrating that Bilby is comparable across waveforms.
> A comparison of both Bilby and LALInference run using IMRPhenomPv2 with and without calibration on GW150914, demonstrating similar changes in the source-parameter posteriors.
>
> Note: only four known events were selected for closer examination, the other seven events from GWTC1 were not inspected. A PE-group publication is planned producing results for all events in GWTC1.
- AOB