Self-sustaining Star Formation Fronts in Filaments during the Cosmic Dawn

Abstract

We propose a new model for the ignition of star formation in low-mass halos by a self-sustaining shock front in cosmic filaments at high redshifts. The gaseous fuel for star formation resides in low mass halos which can not cool on their own due to their primordial composition and low virial temperatures. We show that star formation can be triggered in these filaments by a passing shock wave. The shells swept-up by the shock cool and fragment into cold clumps that form massive stars via thermal instability on a timescale shorter than the front's dynamical timescale. The shock, in turn, is self-sustained by energy injection from supernova explosions. The star formation front is analogous to a detonation wave, which drives exothermic reactions powering the shock. We find that sustained star formation would typically propel the front to a speed of ∼ 300 − 700 km s −1 during the epoch of reionization. Future observations by the James Webb Space Telescope could reveal the illuminated regions of cosmic filaments, and constrain the initial mass function of stars in them.

Cool outflows in galaxies and their implications

“…2.3.2; e.g., Richings and Faucher-Giguère 2018b;Zubovas and King 2014;Decataldo et al 2019;Gronke and Oh 2020). In some of these models, the expectation is that the molecular clouds should become gravitationally unstable, fragment, and form stars inside the outflow (Zubovas et al 2013;Zubovas and King 2014;Ishibashi and Fabian 2012;Ishibashi et al 2013El-Badry et al 2016;Wang and Loeb 2018;Decataldo et al 2019). In these models, the expected star formation inside the outflow could potentially reach hundreds of solar masses per year.…”

Cool Outflows in Galaxies and their Implications

“…Richings and Faucher-Giguère 2018b;Zubovas and King 2014;Decataldo et al 2019;Gronke and Oh 2019). In some of these models, the expectation is that the molecular clouds should become gravitationally unstable, fragment, and form stars inside the outflow (Zubovas et al 2013;Zubovas and King 2014;Ishibashi and Fabian 2012;Ishibashi et al 2013El-Badry et al 2016;Wang and Loeb 2018;Decataldo et al 2019). In these models, the expected star formation inside the outflow could potentially reach hundreds of solar masses per year.…”