Periodic Reporting for period 2 - FutureLSS (Fundamental physics from the large-scale structure of the Universe)
Período documentado: 2022-03-01 hasta 2023-08-31
This project addresses age-old questions like "How did the Universe begin?" and "How will the Universe end?". As such, this project has the potential to revolutionize how we see our role in the Universe. Additionally, the analysis we perform on these datasets uses cutting-edge statistical techniques which we generally make publically available. This project already published four statistical analysis tools as Python packages, which now have been downloaded >70000 times significantly impacting/improving statistical analysis far beyond astronomy.
The second experiment involved in this project (the Eucllid space satellite) did encounter some issues caused by the Russian invasion of Ukraine since this satellite was scheduled to be launched with a Russian Soyuz rocket. Since such collaborations with Russia have now stopped, the launch of Euclid was unclear for some time. However, negotiations with SpaceX have now resulted in a new launch window starting on July 1st, 2023 using Falcon 9 rocket. Currently, the Euclid satellite is on its way to the North American launch site. It now seems very certain that this dramatic re-schedule of the launch vehicle will not lead to any delay and we should have the first Euclid data later this year.
The team working on this project has grown following almost exactly the planned hiring schedule given in the original proposal. For the first year, Dr Mike Wang was working on this project alongside me, while in the second year, Dr Richard Neveux and Thiago Mergulhao were hired. Very recently Dr Samuel Brieden joined as a fourth team member. Dr. Alex Smith was hired on a 6 months contract to help with the production of synthetic DESI datasets used during validation.
The main task was the implementation of the bispectrum analysis pipeline, which Mike has now finished and published. While the estimator is now implemented, we are still working on other aspects of the analysis pipeline. Richard has taken on the task of implementing the perturbative model and Samuel has now started working on an analytic pipeline to forecast and validate our constraints. All team members are part of the DESI and Euclid collaborations and we all attend several regular Zoom calls and collaboration meetings.
In the first year of his PhD, Thiago implemented the primordial feature analysis pipeline and applied it to two existing datasets (BOSS and eBOSS), which has now been published. The attached image shows the constraints on linear primordial features and in particular, it shows how the different datasets allow extending the parameter space to higher frequencies. The paper by Thiago did investigate how to optimally exploit these datasets to obtain the best possible constraints. This analysis pipeline is now ready to be applied to DESI and Thiago has already started working with internal mock datasets to include the DESI-specific systematics mitigation.
I am personally leading the effort on the analysis of relativistic effects in DESI where I am organising the weekly Zoom calls, helping to prepare the mock catalogues needed for the analysis and setup the modelling pipeline. The work on relativistic mocks was supported by Dr. Alex Smith who joined the project on a 6 months contract last year.
Our forecasts suggest that we should be able to have a first detection of relativistic effects in DESI and given that the year 1 analysis already contains 50% of the bright sample due to the excellent performance of the instrument, the first detection might well happen in this first sample. This is a very novel approach which hasn't been tried so far. The study of instrumental and theoretical systematics will take a few more months, but I do believe that we can finish this project alongside the main DESI science analysis this year.
As part of the project, we also aim to publish the statistical analysis tools. So far we have published two tools for statistical parameter inference (Zeus, https://zeus-mcmc.readthedocs.io/en/latest/ and Pocomc, https://pocomc.readthedocs.io/en/latest/)) which now have acquired >70 000 downloads. We have also published an emulator for the galaxy power spectrum (matryoshka, https://matryoshka-emu.readthedocs.io/en/latest/) and the bispectrum estimator (triumvirate, https://triumvirate.readthedocs.io/en/latest/tutorials/QuickGuide.html).