Massive Scalar Field Perturbations of Black Holes Surrounded by Dark Matter

TL;DR

This paper investigates scalar field perturbations around black holes in dark matter environments, revealing how dark matter influences quasinormal modes and their decay rates, with implications for gravitational wave signals.

Contribution

It introduces a detailed analysis of scalar perturbations in black holes surrounded by perfect fluid dark matter, highlighting the impact on quasinormal mode frequencies and decay behaviors.

Findings

Higher angular modes are longer-lived for small scalar masses.

Dark matter parameter k alters quasinormal frequencies compared to Schwarzschild.

Critical scalar mass and frequencies depend on dark matter intensity.

Abstract

We consider scalar field perturbations in the background of black holes immersed in perfect fluid dark matter (PFDM). We find, by using the sixth order Wentzel-Kramers-Brillouin (WKB) approximation, that the longest-lived modes are the ones with higher angular number, for a scalar field mass smaller than a critical value, known as anomalous decay rate of the quasinormal modes, while that beyond this critical value the behaviour is inverted. Moreover, we show that it is possible to recover the real part of the quasinormal frequencies (QNFs), the imaginary part of the QNFs, and the critical scalar field mass, of the Schwarzschild background for different values of the PFDM intensity parameter $k$, respectively. For values of $k$ smaller than these values, the mentioned quantities are greater than the Schwarzschild background. However, beyond of these values of $k$, these quantities are smaller than the Schwarzschild background.