Issue |
A&A
Volume 680, December 2023
|
|
---|---|---|
Article Number | A91 | |
Number of page(s) | 13 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361/202347235 | |
Published online | 15 December 2023 |
Back to the present: A general treatment for the tidal field from the wake of dynamical friction
1
Tartu Observatory, University of Tartu, Observatooriumi 1, Tõravere 61602, Estonia
e-mail: rain.kipper@ut.ee
2
Department of Physics and the Asher Space Science Institute, Technion – Israel Institute of Technology, Haifa 3200003, Israel
3
Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia
Received:
20
June
2023
Accepted:
10
October
2023
Context. Dynamical friction can be a valuable tool for inferring dark matter properties that are difficult to constrain by other methods. Most applications of dynamical friction calculations are concerned with the long-term angular momentum loss and orbital decay of the perturber within its host. This, however, assumes knowledge of the unknown initial conditions of the system.
Aims. We advance an alternative methodology to infer the host properties from the perturber’s shape distortions induced by the tides of the wake of dynamical friction, which we refer to as the tidal dynamical friction.
Methods. As the shape distortions rely on the tidal field that has a predominantly local origin, we present a strategy to find the local wake by integrating the stellar orbits back in time along with the perturber, then removing the perturber’s potential and re-integrating them back to the present. This provides perturbed and unperturbed coordinates and hence a change in coordinates, density, and acceleration fields, which yields the back-reaction experienced by the perturber.
Results. The method successfully recovers the tidal field of the wake based on a comparison with N-body simulations. We show that similar to the tidal field itself, the noise and randomness of the dynamical friction force due to the finite number of stars is also dominated by regions close to the perturber. Stars near the perturber influence it more but are smaller in number, causing a high variance in the acceleration field. These fluctuations are intrinsic to dynamical friction. We show that a stellar density of 0.0014 M⊙ kpc−3 yields an inherent variance of 10% to the dynamical friction.
Conclusions. The current method extends the family of dynamical friction methods that allow for the inference of host properties from tidal forces of the wake. It can be applied to specific galaxies, such as Magellanic Clouds, with Gaia data.
Key words: galaxies: kinematics and dynamics / dark matter / methods: miscellaneous
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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