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

NGC 2915 is a nearby blue compact dwarf with the H  i  properties of a late‐type spiral. Its large, rotating H  i  disc (extending out to   R ∼ 22   B ‐band scalelengths) and apparent lack of stars in the outer H  i  disc make it a useful candidate for dark matter studies. New H  i  synthesis observations of NGC 2915 have been obtained using the Australia Telescope Compact Array. These data are combined with high‐quality 3.6‐μm imaging from the  Spitzer  Infrared Nearby Galaxies Survey. The central regions of the H  i  disc are shown to consist of two distinct H  i  concentrations with significantly non‐Gaussian line profiles. This discredits the idea of a massive H  i  bar constituting the inner H  i  morphology. We fit a tilted ring model to the H  i  velocity field to derive a rotation curve. This is used as input for mass models that determine the contributions from the stellar and gas discs as well as the dark matter halo. The galaxy is dark matter dominated at nearly all radii. At the last measured point of the rotation curve the total mass to blue light ratio is   M  tot / L B  ∼ 140 M ⊙ / L B   , making NGC 2915 one of the darkest galaxies known. We show that the stellar disc cannot account for the steeply rising portion of the observed rotation curve. The best‐fitting dark matter halo is a pseudo‐isothermal sphere with a core density  ρ 0 ∼ 0.17 ± 0.03 M ⊙  pc −3   and a core radius   r  c ∼ 0.9 ± 0.1 kpc .

The dark matter content of the blue compact dwarf NGC 2915