Study of quasinormal modes, greybody factors, and thermodynamics within a regular MOG black hole surrounded by quintessence

In this article, we consider a regular black hole (BH) surrounded by quintessence in the scalar-vector-tensor (S-V-T) version of modified gravity (MOG). We examine the implications of the presence of a quintessence scalar field on astrophysical observable such as quasinormal modes (QNMs), greybody factors (GFs), and thermodynamics. In the vicinity of the MOG BH with quintessence, we calculate the effective potential generated by scalar and electromagnetic field perturbation, and then use the sixth order WKB method to compute the frequencies of the QNMs under these perturbations. We also study the impact of the MOG parameter alpha\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha $$\end{document} and the quintessence parameter c on QNM frequencies. Our investigation reveals that the combined effects of alpha\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha $$\end{document} and c parameters lead to significant decrease in oscillation frequencies, while the imaginary part generally rises. We then examine the GFs associated with the BH and found that as the model parameters alpha\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha $$\end{document} and c increase, GF also increases, and thus less scattering. Additionally, we investigate the thermodynamic quantities and geometries for asymptotically expanded MOG BH. Through heat capacities, Helmholtz and Gibbs free energies, it is observed that this BH shows the stable behavior for various choices of the state parameter of the quintessence omega\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\omega $$\end{document}. It is also interesting to mentioned here that Weinhold geometry exhibits the repulsive nature and Ruppiener geometry provides the attractive nature of MOG on the particles for most of the choices of omega\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\omega $$\end{document}.