Searching for PGWs with CMB exoeriments and their application for time-domain astronomy

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03585
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
• Research Institution: High Energy Accelerator Research Organization (2022-2023); The University of Tokyo (2021)
• Principal Investigator: Chinone Yuji 大学共同利用機関法人高エネルギー加速器研究機構, 量子場計測システム国際拠点, 特任准教授 (90649675)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 観測的宇宙論 / 観測 / データ解析 / マイクロ波観測 / 電波

Outline of Final Research Achievements

Observations of the Cosmic Microwave Background (CMB) were taken using the Simons Array, and data analysis was performed. At present, detection of B-modes from primordial gravitational waves have not been achieved, and further high-sensitivity experiments are essential. By using the observational data from the POLARBEAR experiment, we updated the upper limits of the tensor-to-scalar ratio that POLARBEAR had reported. In addition, we constructed an analytical method to limit axion-like particles from the time-varying polarization angle and analyzed the CMB data observed by POLARBEAR and TauA (Crab Nebula) data. As a result, we achieved the most stringent limits with this type of method (limiting the mass of axion-like particles to the range of (10^{-22}-10^{-18}) eV, based on the limits from TauA).

Free Research Field

観測的宇宙論

Academic Significance and Societal Importance of the Research Achievements

Simons Arrayではインフレーション起源信号を検出する感度を実現できなかったが、半波長板による偏光変調の実証に有効だった。これまで注目されていなかった宇宙マイクロ波背景放射 (CMB)観測実験によるマイクロ波観測データの時間軸の情報を使うことで、アクシオン類似粒子を探査できることを示した。特にCMBおよびTauA (蟹星雲)のデータを解析したの本研究が初めてである。