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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present a new derivation of the star formation history (SFH) of the dSphgalaxy Fornax in two central regions, characterised by unprecedented precisionand age resolution. It reveals that star formation has proceeded in sharpbursts separated by periods of low-level or quiescent activity. The SFH wasderived through colour-magnitude diagram (CMD) fitting of two extremely deepHubble Space Telescope CMDs, sampling the centre and one core radius. Theattained age resolution allowed us to single out a major star formation episodeat early times, a second strong burst $4.6\pm0.4$ Gyr ago and recentintermittent episodes $\sim2-0.2$ Gyr ago. Detailed testing with mock stellarpopulations was used to estimate the duration of the main bursts and study theoccurrence of low-level star formation between them. The SFHs in both regionsshow common features, with activity at the same epochs and similarage-metallicity relationship. However, clear indications of a spatial gradientwere also found, with mean age increasing with radius and star formationepisodes being more prolonged in the centre. While some galaxy evolution modelspredict bursty SFHs in dwarf galaxies and thus a secular origin of the observedSFH cannot be excluded in Fornax, other evidence points to possible mergers orinteractions as the cause of its bursty SFH. In particular, we calculated theFornax orbit relative to the closest dwarfs and the Milky Way and observed acorrespondence between the main intermediate-age and young events andperi-passages of Fornax around the Milky Way, possibly indicatingtidally-induced star formation.

The bursty star formation history of the Fornax dwarf spheroidal galaxy revealed with the HST