Have all questions been asked?

Abstract

My question will be specifically whether energetic neutrinos might play a role in the broad emission line regions of Active Galactic Nuclei. I derive a possible neutrino source from arguments about the heating of the circumnuclear dusty disk which has recently been deduced to exist in most AGN. In normal quasars, the heating of the circumnuclear dusty disk is an unsolved problem. I argue that a flux of relativistic particles, protons and heavy nuclei, with a hard spectrum and an intensity comparable to the flux in electromagnetic radiation is plausible. These particles can easily provide disk heating. Such a flux of energetic particles also invariably leads to an increased flux of neutrinos, with a hard spectrum and extending to very high energies. I note that stars on the main sequence are optically thick to energetic neutrinos, with optical depths of order unity or larger. Then I demonstrate, that a rather moderate flux of neutrinos, at a level of only a few percent to a few tens of percent of the electromagnetic flux changes the internal structure of low mass stars drastically. The stars expand, due to internal heating and begin to look like subgiants or giants. Such stars, exposed to the strong external flux of both electromagnetic radiation and relativistic particles then produce a wind, just as has been argued already for a stellar component in a former compact binary system, of which we now observe only a millisecond pulsar. These winds may contribute to the broad emission line regions in quasars. In fact, the effect of neutrinos is so strong, that it limits the lifetime of low mass stars due to mass loss; such lifetime arguments might be usable to actually put limits on the neutrino flux in quasars.