English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We run controlled N-body experiments to study the evolution of the darkmatter (DM) halo profiles of dwarf galaxies driven by the accretion of DMsubstructures. Our initial conditions assume that supernova feedback erases theprimordial DM cusps of haloes with $10^{9}-10^{10} \rm{M_{\odot}}$ at $z=0$.The orbits and masses of the infalling substructures are borrowed from the {\itAquarius} simulations. Our experiments show that a fraction of haloes thatundergo 1:3 down to 1:30 mergers are susceptible to reform a DM cusp by$z\approx 0$. Cusp regrowth is driven the accretion of DM substructures thatare dense enough reach the central regions of the main halo before beingtidally disrupted. The infall of substructures with a mass ratio above 1:6 onthe mean of the reported mass-concentration relation systematically lead tocusp regrowth. Between 1:6 to 1:8, and 1:8 to 1:30 substructures need to belocated one and two-sigma above the mean, respectively. The merging timescalesof these dense, low-mass substructures is relatively long $(5-11 \rm{Gyrs})$,which may pose a timescale problem for the longevity of DM cores in dwarfgalaxies. These results suggest that a certain level of scatter in the centraldensity slopes of galactic haloes acted-on by feedback is to be expected giventhe stochastic mass accretion histories of low-mass haloes and the diverse starformation histories observed in the Local Group dwarves.

Under the sword of Damocles: plausible regeneration of dark matter cusps at the smallest galactic scales