2014/12/03 by Oliver D. Elbert, James S. Bullock, Shea Garrison-Kimmel +3
Physics and Astronomy · #astro-ph.GA #astro-ph.CO
paper · pdf · doi:10.1093/mnras/stv1470
9 pages, 7 figures
arxiv created 2014/12/03 · arxiv updated 2015/08/19
We investigate the effect of self-interacting dark matter (SIDM) on the density profiles of V\rm max ≃ 40~km~s-1 isolated dwarf dark matter halos -- the scale of relevance for the too big to fail problem (TBTF) -- using very high-resolution cosmological zoom simulations. Each halo has millions of particles within its virial radius. We find that SIDM models with cross sections per unit mass spanning the range σ/m = 0.5 - 50 cm2~g-1 alleviate TBTF and produce constant density cores of size 300-1000 pc, comparable to the half-light radii of M_⋆ ~ 105-7 M_\odot dwarfs. The largest, lowest density cores develop for cross sections in the middle of this range, σ/m ~ 5-10~cm2~g-1. Our largest SIDM cross section run (σ/m = 50~cm2~g-1) develops a slightly denser core owing to mild core-collapse behavior, but it remains less dense than the CDM case and retains a constant density core profile. Our work suggests that SIDM cross sections as large or larger than 50~cm2~g-1 remain viable on velocity scales of dwarf galaxies (v\rm rms ~ 40~km~s-1). The range of SIDM cross sections that alleviate TBTF and the cusp/core problem spans at least two orders of magnitude and therefore need not be particularly fine-tuned.