Aspherical ULDM collapse

Author(s)
Emily Kendall, Mateja Gosenca, Richard Easther
Abstract

Ultralight dark matter (ULDM) is an interesting alternative to the cold dark matter (CDM) paradigm. Due to the extremely low mass of the constituent particle (∼10-22 eV), ULDM can exhibit quantum effects up to kiloparsec scales. In particular, runaway collapse in the centres of ULDM haloes is prevented by quantum pressure, providing a possible resolution to the 'core-cusp problem' of CDM. However, the the detailed relationship between the ULDM core mass and that of the overall halo is poorly understood. We simulate the collapse of both spherical and aspherical isolated ULDM overdensities using AxioNyx, finding that the central cores of collapsed haloes undergo sustained oscillatory behaviour, which affects both their peak density and overall morphology. The asphericity of the post-collapse core fluctuates both quantitatively and qualitatively, with oblate initial overdensities generating cores, which fluctuate between prolate and oblate configurations, and more complicated dynamics arising in triaxial scenarios. Furthermore, the peak central densities are higher in spherical configurations. Consequently, astrophysically realistic haloes may exhibit substantial departures from theoretical core-halo profiles and we would expect a significant variance of the properties of haloes with the same mass.

Organisation(s)
Gravitational Physics
External organisation(s)
University of Auckland
Journal
Monthly Notices of the Royal Astronomical Society
Volume
526
Pages
1046-1056
No. of pages
11
ISSN
0035-8711
DOI
https://doi.org/10.1093/mnras/stad2733
Publication date
11-2023
Peer reviewed
Yes
Austrian Fields of Science 2012
103036 Theoretical physics
Keywords
ASJC Scopus subject areas
Astronomy and Astrophysics, Space and Planetary Science
Portal url
https://ucrisportal.univie.ac.at/en/publications/aspherical-uldm-collapse(c1a76daf-ff03-48b3-a0c8-64396d4ab936).html