000002120 001__ 2120
000002120 005__ 20160701171659.0
000002120 0247_ $$2DOI$$a10.1093/mnras/stu2173
000002120 037__ $$aASTROimport-277
000002120 100__ $$aChatzikos, M.
000002120 245__ $$aImplications of coronal line emission in NGC 4696*
000002120 260__ $$c2015
000002120 520__ $$aWe announce a new facility in the spectral code CLOUDY that enables tracking the evolution of a cooling parcel of gas with time. For gas cooling from temperatures relevant to galaxy clusters, earlier calculations estimated the [Fe XIV] λ5303/[Fe X] λ6375 luminosity ratio, a critical diagnostic of a cooling plasma, to slightly less than unity. By contrast, our calculations predict a ratio of ˜3. We revisit recent optical coronal line observations along the X-ray cool arc around NGC 4696 by Canning et al., which detected [Fe X] λ6375, but not [Fe XIV] λ5303. We show that these observations are not consistent with predictions of cooling flow models. Differential extinction could in principle account for the observations, but it requires extinction levels (AV > 3.625) incompatible with previous observations. The non-detection of [Fe XIV] implies a temperature ceiling of 2.1 million K. Assuming cylindrical geometry and transonic turbulent pressure support, we estimate the gas mass at ˜1 million M⊙. The coronal gas is cooling isochorically. We propose that the coronal gas has not condensed out of the intracluster medium, but instead is the conductive or mixing interface between the X-ray plume and the optical filaments. We present a number of emission lines that may be pursued to test this hypothesis and constrain the amount of intermediate-temperature gas in the system. 
000002120 700__ $$a Williams, R. J. R.
000002120 700__ $$a Ferland, G. J.
000002120 700__ $$a Canning, R. E. A.
000002120 700__ $$a Fabian, A. C.
000002120 700__ $$a Sanders, J. S.
000002120 700__ $$a van Hoof, P. A. M.
000002120 700__ $$a Johnstone, R. M.
000002120 700__ $$a Lykins, M.
000002120 700__ $$a Porter, R. L.
000002120 773__ $$c1234-1244$$i2$$pMonthly Notices of the Royal Astronomical Society$$v446$$y2015
000002120 85642 $$ahttp://esoads.eso.org/abs/2015MNRAS.446.1234C
000002120 905__ $$apublished in
000002120 980__ $$aREFERD