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

We use long-slit spectroscopy from Moran et al. to study the radialdependence of the recent star formation histories of nearby galaxies withstellar masses greater than 10^10M_sun. We fit stellar population models to thecombination of SSFR, D4000 and Hdelta_A and show that many galaxies have Balmerabsorption line equivalent widths that require recent short-lived episodes orbursts of star formation. The fraction of galaxies that have experiencedepisodic rather than continuous star formation is highest for late-typegalaxies with low stellar masses. In these systems, bursts occur both in theinner and outer regions of the galaxy. The fraction of stars formed in a singleburst episode is typically around 15% of the total stellar mass in the innerregions of the galaxy and around 5% of the mass in the outer regions. When weaverage over the population, we find that such bursts contribute around a halfof the total mass in stars formed in the last 2 Gyr. In massive galaxies,bursts occur predominantly in the outer disk. Around a third of all massive,bulge-dominated galaxies have experienced recent star formation episodes thatare fully confined to their outer (R > 0.7R_90) regions. The fraction of starsformed in a single episode is only 2 - 3 % of the underlying stellar mass, butsuch bursts contribute nearly all the stellar mass formed in the last 2 Gyr.Recent star formation in outer disks is strongly correlated with the globalatomic gas fraction of the galaxy, but not its global molecular gas fraction.We suggest that outer episodic star formation is triggered by gas accretionevents.

Spatially resolved star formation histories of nearby galaxies: evidence for episodic star formation in discs