BlastBerries: How Supernovae Affect Lyman Continuum Escape Fractions and Ionizing Photon Production in Local Analogs of High-Redshift Galaxies

While compact, star-forming galaxies are believed to play a key role in cosmic reionization, the physical mechanisms enabling the escape of ionizing photons through the galactic interstellar medium remain unclear. Supernova (SN) feedback is one possible mechanism for clearing neutral gas channels to allow the escape of Lyman continuum photons. Here, we use SN discoveries in low-redshift analogs of high-redshift star-forming galaxies – Green Pea galaxies and their even lower-redshift counterparts, Blueberry (BB) galaxies – to understand how SNe shape the properties of their host galaxies at high redshifts. We cross-match 1242 BB galaxies with transient discovery reports and identify 11 SNe, ten of which are likely core-collapse SNe, and compare their hosts to the larger BB population. We find that SN-hosting BBs exhibit elevated star formation rates, burstier star formation histories within the last $\sim$50 Myr, and higher stellar masses. We estimate the occurrence rates of SNe in BB galaxies, finding that the SN rate may be slightly suppressed in BBs compared to field galaxies of similar mass, but we are unable to fully control for observational uncertainties. Finally, SN hosts show bluer UV slopes than non-host BB galaxies at 2.1$σ$ significance and lower ionizing photon production efficiency at 7.9$σ$ significance; the former result offers modest support for the hypothesis that SN-driven feedback plays a role in facilitating the escape of ionizing photons, while the latter may imply that SN-driven quenching decreases the rate of ionizing photon production in compact star-forming galaxies during the epoch of reionization.

💡 Research Summary

The paper investigates how supernova (SN) feedback influences the escape of Lyman‑continuum (LyC) photons and the production efficiency of ionizing photons (ξ_ion) in low‑redshift analogs of high‑redshift star‑forming galaxies. The authors focus on “Blueberry” (BB) galaxies—compact, low‑mass systems at z < 0.12 that share many properties with the Green Pea (GP) galaxies and, by extension, with the typical galaxies thought to dominate reionization at 6 ≲ z ≲ 12.

Sample construction and SN identification
Two public GP catalogs (LAMOST‑based 1,547 objects and SDSS‑based 835 objects) are combined and filtered to the BB regime (z < 0.12, r‑band half‑light radius < 5″, strong