Can I read Gravitational Wave Memory Imprints on the CMB from Populations of Massive Black Hole Mergers on EtoBox?

Gravitational Wave Memory Imprints on the CMB from Populations of Massive Black Hole Mergers by Zwick, Lorenz; O'Neill, David; Hendriks, Kai; Kirkeberg, Philip; Miravet-Tenés, Miquel is a scholarly article available to read on EtoBox.

What is Gravitational Wave Memory Imprints on the CMB from Populations of Massive Black Hole Mergers about?

Aims: To showcase and characterise the rich phenomenology of temperature fluctuation patterns that are imprinted on the CMB by the gravitational wave memory (GWM) of massive black hole (BH) mergers. Methods: We analyse both individual binaries as well as populations of binaries, distributed in local cosmological boxes at a given redshift. Results: The magnitude of the temperature fluctuations scales primarily as a function of binary total mass and pattern angular scale, and accumulates as a random-walk process when populations of mergers are considered. Fluctuations of order $\sim 10^{-10}$ K are easily reached across scales of $\sim 1'$ to $\sim 1^{\circ}$ for realistic volumetric merger rates of 10$^{-3}$ Mpc$^{-3}$ Gyr$^{-1}$, as appropriate for massive galaxies at $z=1$. We determine numerically that GWM temperature fluctuations result in a universal power spectrum with a scaling of $P(k)\propto k^{-2.7}$. Conclusion: While not detectable given the limitations of current all-sky CMB surveys, our work explicitly shows how every black hole merger in the Universe left us its unique faint signature.

Author

Zwick, Lorenz; O'Neill, David; Hendriks, Kai; Kirkeberg, Philip; Miravet-Tenés, Miquel

Published

2024

Language

EN