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

The stellar initial mas function (IMF) has been described as being invariant,bottom heavy or top-heavy in extremely dense star burst conditions. To provideusable observable diagnostic we calculate redshift dependent spectral energydistributions of stellar populations in extreme star burst clusters which arelikely to have been the precursors of present day massive globular clusters(GCs) and of ultra compact dwarf galaxies (UCDs). The retention fraction ofstellar remnants is taken into account to asses the mass to light ratios of theageing star-burst. Their redshift dependent photometric properties arecalculated as predictions for James Webb Space Telescope (JWST) observations.While the present day GCs and UCDs are largely degenerate concerningbottom-heavy or top-heavy IMFs, a metallicity- and density-dependent top-heavyIMF implies the most massive UCDs, at ages <100 Myr, to appear as objects withquasar-like luminosities with a 0.1-10% variability on a monthly time scale dueto core collapse supernovae.

The formation of UCDs and massive GCs: Quasar-like objects for testing for a variable stellar initial mass function (IMF)