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EP: Fachverband Extraterrestrische Physik
EP 15: Astrophysics III
EP 15.5: Vortrag
Freitag, 4. April 2025, 14:45–15:00, ZHG101
Signatures of Exploding Supermassive PopIII Stars at High Redshift — •Cédric Jockel — Max Planck Institute for Gravitational Physics, Potsdam, Germany
Recently, supermassive black holes (SMBHs) of ∼ 100 million solar-masses have been discovered at high redshifts of z∼ 9−11. These large masses so early in the universes history pose severe challenges to our understanding of SMBH formation. One possible formation channel is the direct collapse of rapidly accreting PopIII stars that form in large collapsing halos of primordial gas and grow up to a million solar masses. Our recent studies and also work by other groups show that they eventually collapse and produce powerful supernova-like explosions of 1055 erg that last over 10 years. Modelling the observational signatures and prospects of their explosions will give us crucial insight on the early stages of SMBH formation. In this talk, I present our recent work on the observability of these supermassive star explosions including the computation of the luminosity, photometry and colour evolution. In our model, we study the scenario where massive ejecta are released during the collapse and explosion and interact with the surrounding dense cloud via shocks. These shock interactions power emissions of up to ∼ 1045−47 erg/s in the source frame and lead to easily observable signals in JWST and EUCLID. Due to the long explosion timescale of over 10-15 years, the transients will be observed over a period of a few hundred years due to redshift and might be confused photometrically with persistent high-redshift sources such as little red dots.
Keywords: JWST; supermassive black holes; PopIII stars; high-redshift universe; supermassive stars