Multiwavelength Analysis of Six Luminous Fast Blue Optical Transients
August 2026 • 2026ApJ..1007...38S
Abstract • We present early (≲1 yr) multiwavelength observations and analysis of six luminous fast blue optical transients (LFBOTs). We identified these LFBOTs in Zwicky Transient Facility survey data from their fast light-curve evolution (t1/2 ≤ 12 days), blue colors at peak brightness (g − r ≤ −0.2 mag), a visible host galaxy, high optical luminosity (Mg < −20 mag), and an X-ray and/or radio detection. With the exception of AT2024aehp (ZTF24abygbss), these transients exhibit peaks in their 10 GHz radio light curves at trest ≍ 50─100 days, with peak radio luminosities ranging from 1038 to 1040 erg s−1. Modeling the radio emission as synchrotron radiation indicates a fast (v = 0.1─0.3c) shock in a dense (ne ≍ 103─104 cm−3) medium. The X-ray emission varies by ≍2 orders of magnitude in luminosity (1042─1044 erg s−1) at trest ∼ 20 days. Analysis of the host-galaxy photometry and spectroscopy for each transient shows that LFBOTs are predominantly nonnuclear (a few kiloparsecs offset) with star-forming host galaxies of stellar masses = 109─1011 M⊙. Unlike all other LFBOTs to date, AT2024aehp exhibited a luminous (M < −19 mag) plateau in the optical light curve and its 6─15 GHz radio emission brightened by over an order of magnitude from trest ≍ 70 to 130 days. The mostly consistent radio behavior between these LFBOTs implies a similar circumburst medium, leading us to prefer a progenitor scenario in which mass is lost in a consistent way shortly prior to the terminal event.
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