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 Plus annual

Presents the access of premium content as premium feature

Premium Content

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 annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Rotation curves of galaxies probe their total mass distributions, includingdark matter. Dwarf galaxies are excellent systems to investigate the darkmatter density distribution, as they tend to have larger fractions of darkmatter compared to higher mass systems. The core-cusp problem describes thediscrepancy found in the slope of the dark matter density profile in thecentres of galaxies ($\beta^*$) between observations of dwarf galaxies(shallower cores) and dark matter-only simulations (steeper cusps). Weinvestigate $\beta^*$ in six nearby spiral dwarf galaxies for whichhigh-resolution CO $J=1-0$ data were obtained with ALMA. We derive rotationcurves and decompose the mass profile of the dark matter using our CO rotationcurves as a tracer of the total potential and 4.5$\mu$m photometry to definethe stellar mass distribution. We find $\langle\beta^*\rangle = 0.6$ with astandard deviation of $\pm0.1$ among the galaxies in this sample, in agreementwith previous measurements in this mass range. The galaxies studied are on thehigh stellar mass end of dwarf galaxies and have cuspier profiles than lowermass dwarfs, in agreement with other observations. When the same definition ofthe slope is used, we observe steeper slopes than predicted by the FIRE andNIHAO simulations. This may signal that these relatively massive dwarfsunderwent stronger gas inflows toward their centres than predicted by thesesimulations, that these simulations over-predict the frequency of accretion orfeedback events, or that a combination of these or other effects are at work.

Cuspy dark matter density profiles in massive dwarf galaxies