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 catalog and results for the cluster system of the starburstgalaxy NGC 4449 based on multi-band imaging observations taken as part of theLEGUS and Halpha-LEGUS surveys. We improve the spectral energy fitting methodused to estimate cluster ages and find that the results, particularly for olderclusters, are in better agreement with those from spectroscopy. The inclusionof Halpha measurements, the role of stochasticity for low mass clusters, theassumptions about reddening, and the choices of SSP model and metallicity allhave important impacts on the age-dating of clusters. A comparison with agesderived from stellar color-magnitude diagrams for partially resolved clustersshows reasonable agreement, but large scatter in some cases. The fraction oflight found in clusters relative to the total light (i.e., T_L) in the U, B,and V filters in 25 different ~kpc-size regions throughout NGC 4449 correlateswith both the specific Region Luminosity, R_L, and the dominant age of theunderlying stellar population in each region. The observed cluster agedistribution is found to decline over time as dN/dt ~ t^g, with g=-0.85+/-0.15,independent of cluster mass, and is consistent with strong, early clusterdisruption. The mass functions of the clusters can be described by a power lawwith dN/dM ~ M^b and b=-1.86+/-0.2, independent of cluster age. The mass andage distributions are quite resilient to differences in age-dating methods.There is tentative evidence for a factor of 2-3 enhancement in both the starand cluster formation rate ~100 - 300 Myr ago, indicating that clusterformation tracks star formation generally. The enhancement is probablyassociated with an earlier interaction event.

LEGUS and Halpha-LEGUS Observations of Star Clusters in NGC 4449: Improved Ages and the Fraction of Light in Clusters as a Function of Age