Star formation trends in high-redshift galaxy surveys: the elephant or the tail?

TL;DR

This paper examines discrepancies in star formation rate and stellar mass relationships at high redshift, highlighting how minor observational errors and sample selection biases can significantly affect interpretations.

Contribution

It investigates causes of conflicting results in high-redshift galaxy studies and explores the physical origin of star formation and mass correlations within hierarchical models.

Findings

Minor observational errors can cause major misinterpretations.

Sample selection biases significantly impact results.

Physical origin of SFR-mass correlation is linked to hierarchical galaxy formation.

Abstract

Star formation rate and accummulated stellar mass are two fundamental physical quantities that describe the evolutionary state of a forming galaxy. Two recent attempts to determine the relationship between these quantities, by interpreting a sample of star-forming galaxies at redshift of z~4, have led to opposite conclusions. We use a model galaxy population to investigate possible causes for this discrepancy and conclude that minor errors in the conversion from observables to physical quantities can lead to major misrepresentation when applied without awareness of sample selection. We also investigate, in a general way, the physical origin of the correlation between star formation rate and stellar mass within hierarchical galaxy formation theory.