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Explaining the oblate morphology of dwarf spheroidals with wave dark matter perturbations.

Authors :
Della Monica, Riccardo
de Martino, Ivan
Broadhurst, Tom
Source :
Monthly Notices of the Royal Astronomical Society. Nov2024, Vol. 534 Issue 3, p2196-2203. 8p.
Publication Year :
2024

Abstract

We investigate whether the oblate, spheroidal morphology of common dwarf spheroidal galaxies (dSph) may result from the slow relaxation of stellar orbits within a halo of wave dark matter (⁠|$\psi$| DM) when starting from an initial disc of stars. Stellar orbits randomly walk over a Hubble time, perturbed by the pervasive 'granular' interference pattern of |$\psi$| DM, that fully modulates the dark matter density on the de Broglie scale. Our simulations quantify the level of stellar disc thickening over the Hubble time, showing that distribution of stars is predicted to become an oblate spheroid of increasing radius, that plausibly accounts for the morphology of dSph galaxies. We predict a low level of residual rotation remains after a Hubble time at the 1–3 km/s level, depending on orientation, that compares with recent claims of rotation for some well-studied local dSph galaxies. This steady internal dynamical evolution may be witnessed directly with JWST for well-resolved dwarf galaxies, appearing more oblate with look back time and tending to small discs of young stars at high redshift. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00358711
Volume :
534
Issue :
3
Database :
Academic Search Index
Journal :
Monthly Notices of the Royal Astronomical Society
Publication Type :
Academic Journal
Accession number :
180502775
Full Text :
https://doi.org/10.1093/mnras/stae2194