The Environments of Green Pea Galaxies. III. The SFACT Sample within the HectoMAP Survey Area

We investigate the environments of N = 14 Green Pea galaxies (GPs) detected in the Star Formation Across Cosmic Time (SFACT) survey in order to determine if environment drives the star formation activity seen within these extreme starbursts. The subsample of SFACT GPs used in this study were detected via their strong [O iii ] λλ 4959,5007 emission lines and span the redshift range 0.31–0.49. In order to analyze the local galactic environments surrounding the SFACT GPs, we utilize a deep spectroscopic environment comparison sample (ECS) that extends 1–2 magnitudes below M *. The ECS facilitates the use of three environmental estimators that probe spatial scales from hundreds of kiloparsecs to tens of megaparsecs. Using the three estimators, we classify the environments into different categories, from extremely isolated to cluster environments. We find that 9 of the 14 SFACT GPs (64%) in our sample are located in regions that exhibit extremely low-density environments. We interpret these results to indicate that, within the limits of our ECS, we find no evidence that luminous companions are required to produce GPs, consistent with previous results. Given the depth of our ECS, we are unable to investigate possible interactions with lower-luminosity companions. One SFACT GP may be in a dense group, but none are found to reside in the highest-density environments, such as clusters.