Constraints on the star formation histories of galaxies in the Local Cosmological Volume

P. Kroupa*, M. Haslbauer, I. Banik, S. T. Nagesh, J. Pflamm-Altenburg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)
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Abstract

The majority of galaxies with current star formation rates (SFRs), SFRo≥10−3M⊙yr−1⁠, in the Local Cosmological Volume, where observations should be reliable, have the property that their observed SFRo is larger than their average SFR. This is in tension with the evolution of galaxies described by delayed-τ models, according to which the opposite would be expected. The tension is apparent in that local galaxies imply the star formation time-scale τ ≈ 6.7 Gyr, much longer than the 3.5–4.5 Gyr obtained using an empirically determined main sequence at several redshifts. Using models where the SFR is a power law in time of the form ∝(tt1)η for t1 = 1.8 Gyr (with no stars forming prior to t1) implies that η = 0.18 ± 0.03. This suggested near-constancy of a galaxy’s SFR over time raises non-trivial problems for the evolution and formation time of galaxies, but is broadly consistent with the observed decreasing main sequence with increasing age of the Universe.

Original languageEnglish
Pages (from-to)37-43
Number of pages7
JournalMonthly Notices of the Royal Astronomical Society
Volume497
Issue number1
Early online date22 Jul 2020
DOIs
Publication statusPublished - Sept 2020

Keywords

  • Galaxies: evolution
  • Galaxies: formation
  • Galaxies: star formation
  • Galaxies: stellar content
  • Galaxy: evolution
  • Galaxy: formation

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