English

Slowly rotating Bose-Einstein Condensate confronted with the rotation curves of 12 dwarf galaxies

Astrophysics of Galaxies 2020-01-22 v1 General Relativity and Quantum Cosmology

Abstract

We assemble a database of 12 dwarf galaxies, for which optical (R-band) and near-infrared (3.6μm3.6\mu m) surface brightness density together with spectroscopic rotation curve data are available, in order to test the slowly rotating Bose-Einstein Condensate (srBEC) dark matter model. We aim to establish the angular velocity range compatible with observations, bounded from above by the requirement of finite size halos, to check the modelfits with the dataset, and the universality of the BEC halo parameter R\mathcal{R}. We construct the spatial luminosity density of the stellar component of the dwarf galaxies based on their 3.6μm3.6\mu m and R-band surface brightness profiles, assuming an axisymmetric baryonic mass distribution. We build up the gaseous component by employing a truncated disk model. We fit a baryonic plus dark matter combined model, parametrized by the M/L ratios of the baryonic components and parameters of the srBEC (the central density ρc\rho_c, size of the static BEC halo R\mathcal{R}, angular velocity ω\omega) to the rotation curves. The 3.6μm3.6\mu m surface brightness of 6 galaxies indicates the presence of a bulge and a disk component. The shape of the 3.6μm3.6\mu m and R-band spatial mass density profiles being similar is consistent with the stellar mass of the galaxies emerging wavelength-independent. The srBEC model fits the rotation curve of 11 galaxies out of 12 within 1σ1\sigma significance level, with the average of R\mathcal{R} as 7.51 kpc and standard deviation of 2.96 kpc. This represents an improvement over the static BEC modelfit. For the well-fitting 11 galaxies the angular velocities allowing for a finite size srBEC halo are <2.2×1016<2.2\times 10^{-16} 1/s. For a scattering length of the BEC particle of a106a\approx 10^6 fm, the mass of the BEC particle is slightly better constrained than in the static case as m[1.26×1017÷3.08×1017]m\in[1.26\times10^{-17}\div3.08\times10^{-17}] eV/c2^2.

Keywords

Cite

@article{arxiv.1908.06489,
  title  = {Slowly rotating Bose-Einstein Condensate confronted with the rotation curves of 12 dwarf galaxies},
  author = {E. Kun and Z. Keresztes and L. Á. Gergely},
  journal= {arXiv preprint arXiv:1908.06489},
  year   = {2020}
}

Comments

9 pages, 4 tables, 5 figures, submitted to A&A