Dynamical friction in self-interacting ultralight dark matter

Journal Article · 01 March 2024 · Physical Review. D.

DOI: https://doi.org/10.1103/physrevd.109.063501 · OSTI ID:2405020

Glennon, Noah  ^[1]; Musoke, Nathan  ^[2]; Nadler, Ethan O.  ^[3]; Prescod-Weinstein, Chanda  ^[2]; Wechsler, Risa H.  ^[4]

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1. Univ. of New Hampshire, Durham, NH (United States); SLAC
2. Univ. of New Hampshire, Durham, NH (United States)
3. Carnegie Observatories, Pasadena, CA (United States); Univ. of Southern California, Los Angeles, CA (United States)
4. Stanford Univ., CA (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)

Here, we explore how dynamical friction in an ultralight dark matter (ULDM) background is affected by dark matter self-interactions. We calculate the force of dynamical friction on a point mass moving through a uniform ULDM background with self-interactions, finding that the force of dynamical friction vanishes for sufficiently strong repulsive self-interactions. Using the pseudospectral solver ultraDark.jl, we show with simulations that reasonable values of the ULDM self-interaction strength and particle mass cause $$\mathcal{O}$$(1) differences in the acceleration of an object like a supermassive black hole (SMBH) traveling near the center of a soliton, relative to the case with no self-interactions. For example, repulsive self-interactions with λ=10^-90 yield a deceleration due to dynamical friction ≈ 70% smaller than a model with no self-interactions. We discuss the observational implications of our results for SMBHs near soliton centers and for massive satellite galaxies falling into ultralight axion halos and show that outcomes are dependent on whether a self-interaction is present or not.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC); National Science Foundation (NSF)
• Grant/Contract Number: AC02-76SF00515
• OSTI ID: 2405020
• Journal Information: Physical Review. D., Journal Name: Physical Review. D. Journal Issue: 6 Vol. 109; ISSN 2470-0010
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English