Prospects for Revealing Intermediate-mass Black Holes in NGC 1399 Using SKA

Abstract

This study investigates the detectability of intermediate-mass black holes (IMBHs) within the mass range 10 ^2 M _⊙ ≤ M _BH ≤ 10 ^5 M _⊙ in the globular star clusters of NGC 1399 at a frequency of 300.00 MHz. Employing the theoretical Bondi accretion model and the empirical fundamental plane (FP) of black hole accretion, we estimate IMBH masses based on bolometric luminosity and X-ray/radio luminosities, respectively. By simulating a 3 hr observation of 77 globular cluster (GC) candidates using the Square Kilometre Array, we identify radio detection benchmarks indicative of accretion onto IMBHs. Our results show that IMBHs inside the globular star clusters located in NGC 1399 are indeed detectable, with the Bondi accretion model providing IMBH mass estimates ranging from 2.93 × 10 ^3.0±0.39 M _⊙ to 7.43 × 10 ^4.0±0.39 M _⊙ and the empirical FP relation suggesting IMBH mass estimation with 3.41 × 10 ^5.0±0.96 M _⊙ . These findings highlight the presence and detectability of IMBHs in GCs, offering insights into their role as precursors to supermassive black holes and enriching our understanding of black hole formation and evolution in astrophysical environments.

Keywords

• Black holes
• Intermediate-mass black holes
• Accretion
• Globular star clusters