Core-envelope haloes in scalar field dark matter with repulsive self-interaction: fluid dynamics beyond the de Broglie wavelength

Autor(en)

Taha Dawoodbhoy, Paul R. Shapiro, Tanja Rindler-Daller

Abstrakt

Scalar field dark matter (SFDM) comprised of ultralight bosons has attracted great interest as an alternative to standard, collisionless cold dark matter (CDM) because of its novel structure-formation dynamics, described by the coupled Schrödinger-Poisson equations. In the free-field ('fuzzy') limit of SFDM (FDM), structure is inhibited below the de Broglie wavelength, but resembles CDM on larger scales. Virialized haloes have 'solitonic' cores of radius ~λ_deB, surrounded by CDM-like envelopes. When a strong enough repulsive self-interaction (SI) is also present, structure can be inhibited below a second length-scale, λ_SI, with λ_SI > λ_deB - called the Thomas-Fermi (TF) regime. FDM dynamics differ from CDM because of quantum pressure, and SFDM-TF differs further by adding SI pressure. In the small-λ_deB limit, however, we can model all three by fluid conservation equations for a compressible, γ = 5/3 ideal gas, with ideal gas pressure sourced by internal velocity dispersion and, for the TF regime, an added SI pressure, P_SI ∝ ρ². We use these fluid equations to simulate halo formation from gravitational collapse in 1D, spherical symmetry, demonstrating for the first time that SFDM-TF haloes form with cores the size of R_TF, the radius of an SI-pressure-supported (n = 1)-polytrope, surrounded by CDM-like envelopes. In comparison with rotation curves of dwarf galaxies in the local Universe, SFDM-TF haloes pass the ['too-big-to-fail' + 'cusp-core']-test if R_TF ≳ 1 kpc.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

University of Texas, Austin

Journal

Monthly Notices of the Royal Astronomical Society

Band

506

Seiten

2418-2444

Anzahl der Seiten

27

ISSN

0035-8711

DOI

https://doi.org/10.1093/mnras/stab1859

Publikationsdatum

09-2021

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie, 103004 Astrophysik, 103044 Kosmologie

Schlagwörter

ASJC Scopus Sachgebiete

Astronomy and Astrophysics, Space and Planetary Science

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/f703a77b-c96c-4942-b9a6-0eb184038720