Yourong Wang
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Research Subjects
Yourong Wang has a total of 7 co-authors. Here are the top co-authors by number of shared publications:
- Richard Easther
University of Auckland
4 shared publications - Emily Kendall
Department of Physics University of Auckland Private Bag 92019 Auckland New Zealand
3 shared publications - Russell Boey
University of Auckland
2 shared publications - Andrew Eberhardt
Kavli Institute for the Physics and Mathematics of the Universe (WPI)
1 shared publication - Benedikt Eggemeier
Institut für Astrophysik Georg-August-Universität Göttingen D-37077 Göttingen Germany
1 shared publication - J. Luna Zagorac
Department of Physics, Yale University, New Haven, Connecticut 06520, USA
1 shared publication
Latest Publications
- 7 July 2025
- Published by American Physical Society (APS) in Physical Review D
- Vol. 112 (2)
Supermassive binaries in ultralight dark matter solitons
- 7 July 2025
- Published by American Physical Society (APS) in Physical Review D
- Vol. 112 (2)
Supermassive binaries in ultralight dark matter solitons
- Open Access
- 15 May 2024
- Published by American Physical Society (APS) in Physical Review D
- Vol. 109 (10) , 103526
Dynamical friction and black holes in ultralight dark matter solitons
We numerically simulate the motion of a black hole as it plunges radially through an ultralight dark matter (ULDM) soliton. We investigate the timescale in which dynamical friction reduces the kinetic energy of the black hole to a minimum and consider the sensitivity of this timescale to changes in the ULDM particle mass, the total soliton mass, and the mass of the black hole. We contrast our numerical results with a semianalytic treatment of dynamical friction and find that the latter is poorly suited to this scenario. In particular, we find that the backreaction of the soliton to the presence of the black hole is significant, resulting in oscillations in the coefficient of dynamical friction which cannot be described in the simple semianalytical framework. Furthermore, we observe a late-time reheating effect, in which a significant amount of kinetic energy is transferred back to the black hole after an initial damping phase. This complicates the discussion of ULDM dynamical friction on the scales relevant to the final parsec problem.
- 15 May 2024
- Published by American Physical Society (APS) in Physical Review D
- Vol. 109 (10) , 103526
Open AccessDynamical friction and black holes in ultralight dark matter solitons
We numerically simulate the motion of a black hole as it plunges radially through an ultralight dark matter (ULDM) soliton. We investigate the timescale in which dynamical friction reduces the kinetic energy of the black hole to a minimum and consider the sensitivity of this timescale to changes in the ULDM particle mass, the total soliton mass, and the mass of the black hole. We contrast our numerical results with a semianalytic treatment of dynamical friction and find that the latter is poorly suited to this scenario. In particular, we find that the backreaction of the soliton to the presence of the black hole is significant, resulting in oscillations in the coefficient of dynamical friction which cannot be described in the simple semianalytical framework. Furthermore, we observe a late-time reheating effect, in which a significant amount of kinetic energy is transferred back to the black hole after an initial damping phase. This complicates the discussion of ULDM dynamical friction on the scales relevant to the final parsec problem.
- 7 April 2023
- Published by American Physical Society (APS) in Physical Review D
- Vol. 107 (8) , 083014
Multifield ultralight dark matter
Ultralight dark matter (ULDM) is usually taken to be a single scalar field. Here we explore the possibility that ULDM consists of light scalar fields with only gravitational interactions. This configuration is more consistent with the underlying particle physics motivations for these scenarios than a single ultralight field. ULDM halos have a characteristic granular structure that increases stellar velocity dispersion and can be used as observational constraints on ULDM models. In multifield simulations, we find that inside a halo the amplitude of the total density fluctuations decreases as and that the fields do not become significantly correlated over cosmological timescales. Smoother halos heat stellar orbits less efficiently, reducing the velocity dispersion relative to the single field case and thus weakening the observational constraints on the field mass. Analytically, we show that for equal-mass fields with mass the ULDM contribution to the stellar velocity dispersion scales as . Lighter fields heat the most efficiently and if the smallest mass is significantly below the other field masses the dispersion scales as .- 7 April 2023
- Published by American Physical Society (APS) in Physical Review D
- Vol. 107 (8) , 083014
Multifield ultralight dark matter
Ultralight dark matter (ULDM) is usually taken to be a single scalar field. Here we explore the possibility that ULDM consists of light scalar fields with only gravitational interactions. This configuration is more consistent with the underlying particle physics motivations for these scenarios than a single ultralight field. ULDM halos have a characteristic granular structure that increases stellar velocity dispersion and can be used as observational constraints on ULDM models. In multifield simulations, we find that inside a halo the amplitude of the total density fluctuations decreases as and that the fields do not become significantly correlated over cosmological timescales. Smoother halos heat stellar orbits less efficiently, reducing the velocity dispersion relative to the single field case and thus weakening the observational constraints on the field mass. Analytically, we show that for equal-mass fields with mass the ULDM contribution to the stellar velocity dispersion scales as . Lighter fields heat the most efficiently and if the smallest mass is significantly below the other field masses the dispersion scales as .- 21 March 2022
- Published by American Physical Society (APS) in Physical Review D
- Vol. 105 (6) , 063523
Dynamical friction from ultralight dark matter
We simulate the gravitational dynamics of a massive object interacting with ultralight/fuzzy dark matter (ULDM/FDM), nonrelativistic quantum matter described by the Schrödinger-Poisson equation. We first consider a point mass moving in a uniform background, and then a supermassive black hole (SMBH) moving within a ULDM soliton. After replicating simple dynamical friction scenarios to verify our numerical strategies, we demonstrate that the wake induced by a moving mass in a uniform medium may undergo gravitational collapse that dramatically increases the drag force, albeit in a scenario unlikely to be encountered astrophysically. We broadly confirm simple estimates of dynamical friction timescales for a black hole at the center of a halo but see that a large moving point mass excites coherent “breathing modes” in a ULDM soliton. These can lead to “stone skipping” trajectories for point masses which do not sink uniformly toward the center of the soliton, as well as stochastic motion near the center itself. These effects will add complexity to SMBH-ULDM interactions and to SMBH mergers in a ULDM universe.
- 21 March 2022
- Published by American Physical Society (APS) in Physical Review D
- Vol. 105 (6) , 063523
Dynamical friction from ultralight dark matter
We simulate the gravitational dynamics of a massive object interacting with ultralight/fuzzy dark matter (ULDM/FDM), nonrelativistic quantum matter described by the Schrödinger-Poisson equation. We first consider a point mass moving in a uniform background, and then a supermassive black hole (SMBH) moving within a ULDM soliton. After replicating simple dynamical friction scenarios to verify our numerical strategies, we demonstrate that the wake induced by a moving mass in a uniform medium may undergo gravitational collapse that dramatically increases the drag force, albeit in a scenario unlikely to be encountered astrophysically. We broadly confirm simple estimates of dynamical friction timescales for a black hole at the center of a halo but see that a large moving point mass excites coherent “breathing modes” in a ULDM soliton. These can lead to “stone skipping” trajectories for point masses which do not sink uniformly toward the center of the soliton, as well as stochastic motion near the center itself. These effects will add complexity to SMBH-ULDM interactions and to SMBH mergers in a ULDM universe.