Long-lived quasinormal modes, grey-body factors and absorption cross-section of the black hole immersed in the Hernquist galactic halo

TL;DR

This paper investigates how a Hernquist dark-matter halo influences the quasinormal modes, grey-body factors, and absorption cross-sections of a Schwarzschild black hole, revealing modifications in oscillation and transmission properties.

Contribution

It provides the first detailed analysis of scalar field perturbations around a black hole in a Hernquist halo, including spectrum calculations and physical implications.

Findings

Longer-lived quasinormal modes due to field mass.

Suppression of low-frequency grey-body transmission.

Shift of absorption features to higher frequencies.

Abstract

We analyze quasinormal modes, grey-body factors, and absorption cross-sections of a massive scalar field in the background of a Schwarzschild black hole surrounded by a Hernquist dark-matter halo. The quasinormal spectrum is obtained through the higher-order WKB method and verified by time-domain evolution, showing consistent results. The field mass increases the oscillation frequency and reduces the damping rate, producing longer-lived modes, while variations in the halo parameters lead to moderate shifts in the spectrum. The grey-body factors reveal a suppression of low-frequency transmission and a displacement of their main features toward higher frequencies, resulting in a corresponding shift in the absorption cross-section.