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

Our aim is to provide as clean and as complete a sample as possible of redgiant branch stars that are members of the Hercules dSph galaxy. With thissample we explore the velocity dispersion and the metallicity of the system.Stromgren photometry and multi-fibre spectroscopy are combined to provideinformation about the evolutionary state of the stars (via the Stromgren c_1index) and their radial velocities. Based on this information we have selecteda clean sample of red giant branch stars, and show that foregroundcontamination by Milky Way dwarf stars can greatly distort the results. Ourfinal sample consists of 28 red giant branch stars in the Hercules dSph galaxy.Based on these stars we find a mean photometric metallicity of -2.35 dex whichis consistent with previous studies. We find evidence for an abundance spread.Using those stars for which we have determined radial velocities we find asystemic velocity of 45.2 km/s with a dispersion of 3.72 km/s, this is lowerthan values found in the literature. Furthermore we identify the horizontalbranch and estimate the mean magnitude of the horizontal branch of the HerculesdSph galaxy to be V_0=21.17, which corresponds to a distance of 147 kpc. Wehave shown that a proper cleaning of the sample results in a smaller value forthe velocity dispersion of the system. This has implications for galaxyproperties derived from such velocity dispersions.

A photometric and spectroscopic study of the new dwarf spheroidal galaxy in Hercules