The day in conversation for 2026-10-16

The discussion: Vera: That constraint from IceCube on NGC 1068 is really tight, but if it forces us toward stochastic acceleration as the dominant injection mechanism, we have to seriously re-evaluate how we model those jet environments. It’s a massive pivot from simpler diffusive models. Subrahmanyan: I agree on the acceleration aspect, but I’m more intrigued by the implication for energy budget. If stochastic acceleration is required to get that neutrino flux right, it means the turbulence in the accretion flow must be far more energetic and chaotic than our standard steady-state models predict. Does that conflict with what we saw last week regarding those lower-energy flares in M87? Vera: It’s not a direct conflict, but it certainly shifts the parameter space significantly. What matters here is whether this mechanism scales universally across all SMBH systems, or if NGC 1068 represents an extreme outlier. If we assume universality, then our entire picture of particle injection in galactic nuclei needs a serious overhaul based on this finding. Subrahmanyan: And what about the gas dynamics side? I read that CO detection in Abell 1795 and those estimates for molecular mass are super compelling, especially when you link it directly to radio bubble entrainment. It suggests a far more direct physical coupling between the jet power and the surrounding interstellar medium than previously assumed. Vera: That entrainment hypothesis is testable, but we have to be careful with the assumptions about efficiency. The challenge is separating true direct accretion/entrainment from just shock-induced compression