Mon. Not. R. Astron. Soc., 483, 289-298 (2019/February-2)
Scalar field dark matter: helping or hurting small-scale problems in cosmology?
ROBLES V.H., BULLOCK J.S. and BOYLAN-KOLCHIN M.
Abstract (from CDS):
Building upon results of cosmological simulations of ultra-light scalar field dark matter (SFDM), we present a comprehensive model for the density profiles of SFDM haloes as a function of halo virial mass Mh and scalar field mass m. The central regions of SFDM haloes are dominated by solitons with characteristic densities that increase with increasing halo mass and asymptote to CDM-like profiles at large radii. For scalar field masses m ∼ 10–22 eV, consistent with large-scale structure observations, M_ h_ ∼1010 M_☉haloes have lower core densities than their cold dark matter (CDM) counterparts and this alleviates the too big to fail problem in a regime where feedback is less effective. However, higher mass SFDM haloes with M_ h_ ∼1011 M_☉are denser than their CDM counterparts at small, observationally relevant radii. We use rotation curves of V ∼ 100 km s–1 galaxies from the SPARC database to show that SFDM exacerbates the cusp/core and central density problems seen in CDM at this scale. We conclude that if the conventional cosmological SFDM scaling relations are correct, then baryonic feedback is required to lower densities in SFDM haloes even more so than in CDM. This motivates cosmological and self-consistent hydrodynamic simulations of SFDM to determine whether central soliton structure can be altered by realistic feedback implementations.