000001985 001__ 1985
000001985 005__ 20160701171656.0
000001985 0247_ $$2DOI$$a10.1111/j.1745-3933.2008.00463.x
000001985 037__ $$aASTROimport-142
000001985 100__ $$aFerland, G. J.
000001985 245__ $$aThe origin of molecular hydrogen emission in cooling-flow filaments
000001985 260__ $$c2008
000001985 520__ $$aThe optical filaments found in many cooling flows in galaxy clusters consist of low-density (~103cm-3) cool (~103 K) gas surrounded by significant amounts of cosmic-ray and magnetic field energy. Their spectra show anomalously strong low-ionization and molecular emission lines when compared with Galactic molecular clouds exposed to ionizing radiation such as the Orion complex. Previous studies have shown that the spectra cannot be produced by O-star photoionization. Here, we calculate the physical conditions in dusty gas that is well shielded from external sources of ionizing photons and is energized either by cosmic rays or dissipative magnetohydrodynamics waves. Strong molecular hydrogen lines, with relative intensities similar to those observed, are produced. Selection effects introduced by the microphysics produce a correlation between the H2 line upper level energy and the population temperature. These selection effects allow a purely collisional gas to produce H2 emission that masquerades as starlight-pumped H2 but with intensities that are far stronger. This physics may find application to any environment where a broad range of gas densities or heating rates occur. Contains material ┬ęBritish Crown copyright 2008/MoD. E-mail: gary@pa.uky.edu 
000001985 700__ $$a Fabian, A. C.
000001985 700__ $$a Hatch, N. A.
000001985 700__ $$a Johnstone, R. M.
000001985 700__ $$a Porter, R. L.
000001985 700__ $$a van Hoof, P. A. M.
000001985 700__ $$a Williams, R. J. R.
000001985 773__ $$cL72-L76$$i1$$pMonthly Notices of the Royal Astronomical Society$$v386$$y2008
000001985 85642 $$ahttp://esoads.eso.org/abs/2008MNRAS.386L..72F
000001985 905__ $$apublished in
000001985 980__ $$aREFERD