High-temperature behaviour of the helium-like Kα G ratio: the effect of improved recombination rate coefficients for calcium, iron and nickel

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dc.creator Nahar, Sultana Nurun
dc.creator Oelgoetz, J.
dc.creator Fontes, C. J.
dc.creator Zhang, H. L.
dc.creator Montenegro, M.
dc.creator Pradhan, A. K.
dc.date.accessioned 2009-12-30T19:44:53Z
dc.date.available 2009-12-30T19:44:53Z
dc.date.issued 2007
dc.identifier.citation Oelgoetz, J., Fontes, C. J., Zhang, H. L., Montenegro, M., Nahar, Sultana Nurun, Pradhan, A. K. "High-temperature behaviour of the helium-like Kα G ratio: the effect of improved recombination rate coefficients for calcium, iron and nickel," Monthly Notices of the Royal Astronomical Society, v. 382, no. 2, 2007, pp. 761-769. en_US
dc.identifier.issn 1365-2966
dc.identifier.uri http://hdl.handle.net/1811/44625
dc.description Relevant data is available at: http://www.astronomy.ohio-state.edu/~nahar/nahar_radiativeatomicdata/index.html en_US
dc.description The definitive version is available at www.blackwell-synergy.com. http://www3.interscience.wiley.com/journal/117975880/abstract en_US
dc.description.abstract It is shown that above the temperature of maximum abundance, recombination rates into the excited states of He-like ions that are calculated using earlier, more approximate methods differ markedly from rates obtained from recent distorted-wave and R-matrix calculations (unified recombination rate coefficients) for Ca, Fe and Ni. The present rates lead to G ratios that are greatly lower than those resulting from the more approximate rates in previous works, by up to a factor of 6 at high electron temperatures. Excellent agreement between the distorted-wave and the R-matrix rates, as well as excellent agreement in the G ratios calculated from them, provides support for the accuracy of these new values which have a broad applicability to the modelling and interpreting of X-ray spectra from a variety of astrophysical and laboratory sources. en_US
dc.description.sponsorship The work by the OSU group (MM, SNN, AKP) was partially supported by a grant from the NASA Astrophysical Theory Program. en_US
dc.language.iso en_US en_US
dc.subject atomic data en_US
dc.subject atomic processes en_US
dc.subject line -- formation en_US
dc.subject X-rays -- general en_US
dc.title High-temperature behaviour of the helium-like Kα G ratio: the effect of improved recombination rate coefficients for calcium, iron and nickel en_US
dc.type Article en_US
dc.identifier.doi 10.1111/j.1365-2966.2007.12410.x
dc.identifier.osuauthor nahar.1
dc.identifier.osuauthor pradhan.1