Single and merger soliton dynamics in scalar field dark matter with and without self-interactions

Autor(en)

Matthias Stallovits, Tanja Rindler-Daller

Abstrakt

(abridged)Scalar field dark matter (SFDM) made of bosons has become a

popular alternative to the CDM paradigm, especially for its potential to

cure the so-called "small-scale problems" of CDM. Cosmological

simulations have determined that SFDM halos exhibit a core-envelope

structure, but they are computationally expensive. Halo cores have been

found to be well approximated by "solitons". The study of single soliton

and multiple soliton merger dynamics constitutes a more feasible

approach to investigate in detail the genuine quantum dynamics of SFDM

and its interplay with self-gravity for a multitude of free boson

parameters. In this paper, we present dedicated simulations of single

solitons and binary soliton mergers, for models without and with a

2-boson, repulsive, weak to intermediate self-interaction (SI), as well

as multiple soliton mergers without SI. We adapt the open-source code

Pyultralight to simulate solitons with SI and make our amended code

public. We derive numerical scaling relations between the central

density and mass of solitons for several values of SI and find

deviations from the monotonic relations known from fuzzy dark matter (no

SI), or the strongly repulsive Thomas-Fermi regime. Solitons with SI

exemplify larger cores and lower central densities, compared to solitons

without SI. Using our simulations, we extract numerical density profiles

for solitons and postmerger objects, and fit them to analytical

functions of previous literature. We find a mild preference for Gaussian

cores for objects with SI, while the envelopes of postmergers can be fit

to NFW profiles albeit with some caution as we discuss. Similar to

previous work, we find global, persistent oscillations for solitons as

well as postmergers, confirming that self-gravitating SFDM has very long

relaxation times, although objects with SI exhibit oscillations of

comparatively smaller amplitude.

Organisation(en)

Institut für Astrophysik

Journal

Physical Review D

ISSN

2470-0010

Publikationsdatum

06-2024

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie, 103004 Astrophysik, 103044 Kosmologie, 103043 Computational Physics

Schlagwörter

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