Ja. Pons et al., LEGENDRE EXPANSION OF THE NU(NU)OVER-BAR-REVERSIBLE-ARROW-E(-) KERNEL- INFLUENCE OF HIGH-ORDER TERMS()E(), Astronomy & Astrophysics. Supplement series, 129(2), 1998, pp. 343-351
We calculate the Legendre expansion of the rate of the process nu + <(
nu)over bar> <----> e(+) + e(-) up to 3(rd) order estending previous r
esults of other authors which only consider the 0(th) and 1(st) order
terms. Using different closure relations for the moment equations of t
he radiative transfer equation we discuss the physical implications of
taking into account quadratic and cubic terms on the energy depositio
n outside the neutrinosphere in a simplified model. The main conclusio
n is that 2(nd) order is necessary in the semi-transparent region and
gives good results if an appropriate closure relation is used.