H_2 Suppression with Shocking Inflows: Testing a Pathway for Supermassive Black Hole Formation

Understand

The presence of quasars at redshifts z > 6 indicates the existence of supermassive black holes (SMBHs) as massive as a few times 10^9 Msun, challenging models for SMBH formation.

• One pathway is through the direct collapse of gas in T_{vir} > 10^4 K halos; however, this requires the suppression of H_2 cooling to prevent fragmentation.
• In this paper, we examine a proposed new mechanism for this suppression which relies on cold-mode accretion flows leading to shocks at high densities (n > 10^4 cm^{-3}) and temperatures (T > 10^4 K).
• In such gas, H_2 is efficiently collisionally dissociated.