Physics Commons^™

The Origin Of Molecular Hydrogen Emission In Cooling-Flow Filaments, Gary J. Ferland, A. C. Fabian, N. A. Hatch, R. M. Johnstone, R. L. Porter, P. A. M. Vanhoof, R. J. R. Williams

Physics and Astronomy Faculty Publications

The optical filaments found in many cooling flows in galaxy clusters consist of low-density (∼10³ cm⁻³) cool (∼10³ K) gas surrounded by significant amounts of cosmic-ray and magnetic field energy. Their spectra show anomalously strong low-ionization and molecular emission lines when compared with Galactic molecular clouds exposed to ionizing radiation such as the Orion complex. Previous studies have shown that the spectra cannot be produced by O-star photoionization. Here, we calculate the physical conditions in dusty gas that is well shielded from external sources of ionizing photons and is energized either by cosmic rays or dissipative …