Non-parametric Star Formation History Reconstruction with Gaussian Processes I: Counting Major Episodes of Star Formation

Understand

The star formation histories (SFHs) of galaxies contain imprints of the physical processes responsible for regulating star formation during galaxy growth and quenching.

• We improve the Dense Basis SFH reconstruction method of Iyer & Gawiser (2017), introducing a nonparametric description of the SFH based on the lookback times at which a galaxy assembles certain quantiles of its stellar mass.
• The method uses Gaussian Processes to create smooth SFHs that are independent of any functional form, with a flexible number of parameters that is adjusted to extract the maximum possible amount of SFH information from the SEDs being fit.
• We apply the method to reconstruct the SFHs of 48,791 galaxies with $H<25$ at $0.5 < z < 3.0$ across the five CANDELS fields.