2020 Fiscal Year Research-status Report
Probing cosmology with astrophysical gravitational wave background
| Project/Area Number |
20K22348
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
Vardanyan Valeri 東京大学, カブリ数物連携宇宙研究機構, 特任研究員 (10876238)
|
|---|
| Project Period (FY) |
2020-09-11 – 2022-03-31
|
| Keywords | Cosmology / Gravitational Waves / Large Scale Strcuture / Cross-Correlations / Gaussian Processes / Multimessenger astronomy |
|---|
| Outline of Annual Research Achievements |
The past months of the grant period have been very fruitful in terms of research achievements in multiple fronts.
One of the important directions I have already explored is the study of cross-correlations (CC) of a gravitational wave (GW) source catalogue and large scale structure data. In a recently submitted paper I have demonstrated that in the near future CC measurements can precisely and in a model independent manner reconstruct 1) the linear bias parameter of GW sources, 2) the propagation law of gravitational waves across cosmic history. The first finding is very promising in regard to uncovering the origin of GW sources as different source formation mechanisms predict different linear bias parameters. The importance of the second finding is connected to the fact that Modified Gravity theories predict an altered propagation of GWs compared to the prediction of general relativity, and as such my work is a proposal of a valuable framework for testing the laws of gravity at cosmological scales. I am planning to publicly release the code developed for this work in the near future. This paper is strongly related to the objectives number 2) and 3) in the research proposal.
Besides this I am involved in a work carried out within the EUCLID large-scale structure mission, with the aim of forecasting the detectability of the aforementioned CC with the upcoming surveys. Additionally, I am actively working on a soon-to-be-completed project related to gravitational wave background originating in the primordial universe.
|
| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
So far the research progress has been as planned. I have managed to complete a paper addressing the objectives 2) and 3) in the proposal.
The main change compared to the original research proposal is connected to the travel component of the project. The COVID-19 pandemic has significantly altered the travel plans of my grant proposal. While the research component itself has not been significantly affected, I was forced to cancel all my work visits and could not initiate some of the planned collaborations.
|
| Strategy for Future Research Activity |
I am planning to complete the ongoing projects mentioned earlier, as well as releasing the code associated with the paper described in the achievements section.
Additionally, I am in the brainstorming phase for initiating a new project regarding the anisotropic gravitational wave background (GWB) and its cross-correlations with other probes. Particularly, the anisotropic signal from high-redshift stellar binary black hole population could be a promising observable to model. The isotropic signal has been estimated in a recent paper (https://arxiv.org/pdf/2103.12755.pdf), which suggests that one should expect a sizeable GWB signal. Understanding the detectability of anisotropic GWB of such an origin will be among my research topics in the coming months.
In order to partially remedy the COVID-19-induced lack of research-related travels (see above), I have planned (pandemic measures permitting) a 3-week visit to Kyoto University in May/June 2021. I am also monitoring the situation closely in order to plan work visits abroad upon the first such opportunities become available.
|
| Causes of Carryover |
I couldn't travel and invite collaborators because of COVID-19 pandemic restrictions. I will spend the left-over funds in the FY2021 for their original purposes (travel and inviting collaborators). Additionally, I will purchase several items for my research, such as a new computer and a tablet.
|
