- 學位論文
透過 LIGO O3 引力波訊號探索普羅卡星的潛在訊號
Searching for Proca Star Signal in LIGO O3 Gravitational Wave Data
摘要
2015 年 aLIGO 首次直接量測到引力波訊號後，不僅証實百年前阿爾伯特·愛因斯坦於廣義相對論中的預測，也預示著引力波物理會開始蓬勃發展並期望能利用引力波解開宇宙中的其他謎團。目前引力波探測訊號主要來自於不同太陽質量雙星系統的互繞及合併且將雙星判定為黑洞或中子星，然而隨著觀測數據的累積，開始對傳統恆星黑洞形成理論產生挑戰。通常理論不能到達的區段分別被區分為上、下部分質量間隙，其中上半部質量間隙主流描述為 45（60）〜120 太陽質量之間，至今有許多引力波數據表明其來源質量源自於此區間，而普羅卡星便是可以填滿此區間的緻密星體。在此研究中得知普羅卡星為帶質量自旋 1 的玻色子所組成的玻色星體其星體質量可輕易到達質量間隙的範圍內且利用此星體理論上的緊緻度與形變量可與黑洞互相區分，同時這些物理量也會體現在其產生的引力波形之中，若此星體存在則可能為長期尋找的暗物質星體證據並能解決質量間隙的問題。本文主要選取 2020 年與 2021 年公布的 O3a 與 03b 的數據，並從中挑選 22 個位於上半部質量間隙的事件、考慮其雙黑洞、普羅卡星黑洞、雙普羅卡星系統等三種可能情況並使用 Pycbc（A Python-based parameter estimation toolkit for compact binary coalescence signals.）的軟件包中IMRPhenomPv2_NRTidal、IMRPhenomD_NRTidal 進行模板分析且與帶有形變量的模板互相比對，若有形變量的模板相對較佳、其形變量與理論相符則可挖掘出普羅卡星的可能訊號。
並列摘要
As the sensitivity of gravitational wave detection improves, there is more evidence for the existence of compact objects in the pair-instability mass gap. These results are surprising and suggest that some gravitational waves may not come from neutron stars or black holes, but may also due to other compact stars. Proca star is a spherically symmetric object formed by spin-1 massive bosons, and it is one of the gravitational solitons that are dynamically formed in the mass gap and satisfy the classical (incomplete) gravitational collapse process. This paper reviews the tidal deformability of the Proca star and this quantity can be used to distinguish black holes from the Proca star. We select 22 events in the mass gap from the 03a and O3b gravitational wave data released by aLIGO-Virgo. We then applied used PYCBC(A Python-based parameter estimation toolkit for compact binary coalescence signals.) to analyze the data to check whether the tidal parameters in the waveform model are consistent with the theory, and consider the three scenarios of BBH(Binary black hole system), PSBH(Proca star - black hole system), and BPS(Binary Proca star system), and use the Bayes factor to infer possible PS events.