The integrated bispectrum as a test of cosmic microwave background non-Gaussianity: detection power and limits on fNL with WMAP data |
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| Authors: | P Cabella F K Hansen M Liguori D Marinucci S Matarrese L Moscardini N Vittorio |
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| Institution: | Instituto de Astronomía y Meteorología, Av. Vallarta No. 2602, Col. Arcos Vallarta, C.P. 44130 Guadalajara, Jalisco, México |
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| Abstract: | We note that H2 emitting planetary nebulae tend to have Zanstra temperatures T Z(He ii ) > 90 kK . This is shown to be consistent with a large evolutionary lifetime, and the kinematic ages of the envelopes. Non-local thermodynamic equilibrium stellar atmospheric modelling also shows that levels of soft X-ray emission increase more rapidly than has previously been assumed, and are preferentially large in H2 emitting sources. It is suggested that this may hold the key to explaining the strengths of the H2 transitions. |
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| Keywords: | planetary nebulae: general infrared: ISM |
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