Metallicity of stars formed throughout the cosmic history based on the
  observational properties of star forming galaxies
  Metallicity is one of the crucial factors that determine stellar evolution.
To characterize the properties of stellar populations one needs to know the
fraction of stars forming at different metallicities. Knowing how this fraction
evolves over time is necessary e.g. to estimate the rates of occurrence of any
stellar evolution related phenomena (e.g. double compact object mergers, gamma
ray bursts). Such theoretical estimates can be confronted with observational
limits to validate the assumptions about the evolution of the progenitor system
leading to a certain transient. However, to perform the comparison correctly
one needs to know the uncertainties related to the assumed star formation
history and chemical evolution of the Universe.
  We combine the empirical scaling relations and other observational properties
of the star forming galaxies to construct the distribution of the cosmic star
formation rate density at different metallicities and redshifts. We address the
question of uncertainty of this distribution due to currently unresolved
questions, such as the absolute metallicity scale, the flattening in the star
formation--mass relation or the low mass end of the galaxy mass function. We
find that the fraction of stellar mass formed at metallicities <10% solar
(>solar) since z=3 varies by ~18% (~26%) between the extreme cases considered
in our study. This uncertainty stems primarily from the differences in the mass
metallicity relations obtained with different methods. We confront our results
with the local core-collapse supernovae observations. Our model is publicly
available.
