Effects of feedback-free starburst galaxies on the 21-cm signal and reionization history

Understand

Different star-formation models at Cosmic Dawn produce detectable signatures in the observables of upcoming 21-cm experiments.

• In this work, we consider the physical scenario of feedback-free starbursts (FFB), according to which the star-formation efficiency (SFE) is enhanced in sufficiently massive halos at early enough times, thus explaining the indication from the James Webb Space Telescope for an excess of bright galaxies at $z \geq 10$.
• We model the contribution of FFBs to popII SFE and compute the impact these have on the 21-cm global signal and power spectrum.
• We show that FFBs affect the evolution of the brightness temperature and the 21-cm power spectrum, but they only have a limited effect on the neutral hydrogen fraction.