2017/08/31 by Tereza Jeřábková, Tereza Jerabkova, Pavel Kroupa +5
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Dwarf galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Globular cluster #Physics #Stellar, planetary, and galactic studies #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.1051/0004-6361/201731240
published as A&A 608, A53 (2017) · Accepted for publication in A&A, 12 pages, 10 figures + appendix, version 2: language corrections added
openalex publication_date 2017/09/14 · arxiv created 2017/10/23 · arxiv updated 2018/01/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The stellar initial mass function (IMF) has been described as being invariant, bottom-heavy, or top-heavy in extremely dense star-burst conditions. To provide usable observable diagnostics, we calculate redshift dependent spectral energy distributions of stellar populations in extreme star-burst clusters, which are likely to have been the precursors of present day massive globular clusters (GCs) and of ultra compact dwarf galaxies (UCDs). The retention fraction of stellar remnants is taken into account to assess the mass to light ratios of the ageing star-burst. Their redshift dependent photometric properties are calculated as predictions for James Webb Space Telescope (JWST) observations. While the present day GCs and UCDs are largely degenerate concerning bottom-heavy or top-heavy IMFs, a metallicity- and density-dependent top-heavy IMF implies the most massive UCDs, at ages < 100 Myr, to appear as objects with quasar-like luminosities with a 0.1−10% variability on a monthly timescale due to core collapse supernovae.