A new preprint posted to arXiv (not yet peer-reviewed) has examined the environments of luminous fast blue optical transients (LFBOTs), rare bright and short-lived cosmic explosions. Researchers studied the host galaxies of 11 LFBOTs by modeling both new and archival photometry and spectroscopy data using the Prospector code. This approach allowed them to estimate properties such as stellar mass, star formation rate, and metallicity.

All 11 hosts are actively star-forming with recent bursts of star formation. The sample shows a median stellar mass of log(M*/M⊙) = 9.61 (roughly 4 billion solar masses), a present-day star formation rate of about 0.95 solar masses per year, and gas-phase metallicity of 12+log(O/H) = 8.71.

When compared to other transients, LFBOT hosts are more actively star-forming than those of common core-collapse supernovae (SNe Ibc, II, and Ibn) but less active than hosts of hydrogen-poor superluminous supernovae (SLSNe-I). Their metallicities are lower than those of typical SN Ibc and SN II hosts but higher than SLSNe-I and long gamma-ray burst hosts. Notably, more than 30% of LFBOTs occur in the faintest pixel of their host or outside the galaxy's detectable light.

These findings indicate that LFBOTs arise from massive stars yet do not closely track the most active star-forming regions and show weaker dependence on low metallicity than some other extreme events. The authors therefore favor a progenitor model in which a compact object merges with a Wolf-Rayet star.

The study is limited by its small sample size of only 11 events and reliance on a mix of new and archival data; conclusions could change with larger samples. The preprint is available at https://arxiv.org/abs/2603.23597. The authors note that future discoveries with the Rubin Observatory should increase the sample and better constrain LFBOT origins.