Data associated with paper "A Hubble Space Telescope Search for $r$-Process Nucleosynthesis in Gamma-ray Burst Supernovae"

Simulations and indirect observational evidence have suggested that, in addition to the mergers of compact objects, there exists a secondary source of heavy element ($r$-process) nucleosynthesis with a short delay from star formation: the core-collapse of rapidly-rotating and/or highly-magnetized massive stars. Here, we probe a predicted signature of $r$-process enrichment, a late-time ($\gtrsim 40$~days post-burst) distinct red color, in observations of GRB-supernovae (GRB-SNe) which are linked to these massive star progenitors. We present optical to near-IR color measurements of four GRB-SNe at $z \lesssim 0.4$, extending out to $> 500$~days post-burst, obtained with the {\em Hubble Space Telescope} and large-aperture ground-based telescopes. Comparison of our observations to models indicates that GRB\,190829A favors little ($\leq 0.01 M_{\odot}$) $r$-process enrichment whereas GRB\,100316D is consistent with producing $0.03 - 0.15 M_{\odot}$ of $r$-process material. Observations of GRBs\,030329 and 130427A are not on sufficient timescales to robustly constrain enrichment, although taken together the sample of GRB-SNe indicates color diversity at late times. Our sample also disfavors large amounts of mixing between the inner $r$-process ejecta and outer SN layers.
Our derived yields from GRB-SNe may be underestimated due to $r$-process material hidden in the SN ejecta (potentially due to low mixing fractions) or the limits of current models in measuring $r$-process mass. We conclude with recommendations for future search strategies to observe and probe the full distribution of $r$-process produced by GRB-SNe.