The effect of dark matter spikes on galactic black hole ringdown waveforms and shadows

Author:

Ramin G. Daghigh, Gabor Kunstatter

Keyword:

General Relativity and Quantum Cosmology, General Relativity and Quantum Cosmology (gr-qc)

journal:

date:

2023-08-29 16:00:00

Abstract

We investigate the effect of dark matter spikes on the ringdown waveforms and shadows of the supermassive black holes at the core of the Milky Way and M87. The dominant effect comes in the form of a redshift factor due to the mass of the spike and is significant for large supermassive black holes such as M87*. The subdominant contributions, recently calculated in {\it ApJ} {\bf 940} 33 (2022), give information about the distribution of matter in the spike. We show that these subdominant contributions are small as compared to the redshift factor and likely difficult to detect except perhaps for very large black holes. We also show that the effect of a dark matter spike, with density near the observational upper bounds, on the shadow radius of M87* is only an order of magnitude smaller than is currently accessible with Event Horizon Telescope data.

PDF: The effect of dark matter spikes on galactic black hole ringdown waveforms and shadows.pdf